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Sample records for angiography based approach

  1. Transbrachial artery approach for selective cerebral angiography

    Energy Technology Data Exchange (ETDEWEB)

    Touho, Hajime; Karasawa, Jun; Shishido, Hisashi; Morisako, Toshitaka; Numazawa, Shinichi; Yamada, Keisuke; Nagai, Shigeki; Shibamoto, Kenji (Osaka Neurological Inst., Toyonaka (Japan))

    1990-02-01

    Transaxillary or transbrachial approaches to the cerebral vessels have been reported, but selective angiography of all four vessels has not been possible through one route. In this report, a new technique for selective cerebral angiography with transbrachial approach is described. One hundred and twenty three patients with cerebral infarction, vertebrobasilar insufficiency, intracerebral hemorrhage, epilepsy, or cerebral tumor were examined. Those patients consisted of 85 outpatients and 38 inpatients whose age ranged from 15 years old to 82 years old. The patients were examined via the transbrachial approach (97 cases via the right brachial, 29 cases via the left). Materials included a DSA system (Digital Fluorikon 5000, General Electric Co.), a 4 French tight J-curved Simmons 80-cm catheter, a 19-gauge extra-thin-wall Seldinger needle, and a J/Straight floppy 125-cm guide-wire. Generally, the volume of the contrast agent (300 mgI/ml iopamidol) used in the common carotid artery angiogram was 6 ml, while that used in the vertebral artery angiogram was 4 ml. If catheterization of the vertebral artery or right common carotid artery was unsuccessful, about 8 ml of the contrast agent was injected into the subclavian or branchiocephalic artery. Definitive diagnosis and a decision on proper treatment of the patients can be easily obtained, and the results were clinically satisfactory. Moreover, no complications were encountered in this study. This new technique making a transbrachial approach to the cerebral vessels using the DSA system is introduced here. Neurosurgeons can use this technique easily, and they will find that it provides them with all the information they need about the patient. (author).

  2. The feasibility of left radial artery approach for coronary angiography

    Institute of Scientific and Technical Information of China (English)

    Liangbo Chen; Can Chen; Shian Huang

    2008-01-01

    Objective:To study the feasibility of the left radial approach for coronary angiography. Methods:195 patients diagnosed with coronary atherosclerotic heart disease were randomly divided for coronary angiography(CAG) into a left radial artery approach group(98 cases) and a fight radial artery approach group(97 cases) from Jan 2006 to Dec 2006. Selective coronary angiographies were performed with 5F TIG catheters. The time of puncturing, duration under X-ray fluoroscopy and of the operation, successful rates of puncturing and coronary angiography were recorded. Results:There was no difference in the time of puncturing(2.25 -F 1.58 min vs 2.19±1.62 min), duration under X-ray fluoroscopy(3.12±1.53 min vs 3.21±1.49 min) and the duration of the operation(12.87±2.52 rain vs 12.98±2.85 min), nor in the success rates of puncturing(95.91% vs 95.87%) and coronary angiography(94.90% vs 94.85%). Conclusion: Coronary angiography can be accomplished via the left radial artery approach, indicating that this is a worthwhile clinical approach.

  3. The Hunter pulmonary angiography catheter for a brachiocephalic vein approach.

    Science.gov (United States)

    Rosen, Galia; Kowalik, Karen J; Ganguli, Suverano; Hunter, David W

    2006-01-01

    The purpose of this work was to describe our experience in performing pulmonary angiography using the Hunter pulmonary catheter, manufactured by Cook, Inc., which is a modified 6F pigtail catheter with a "C-shaped" curve, designed for a brachiocephalic vein approach. One hundred twenty-three patients underwent pulmonary angiograms using the Hunter catheter between August 1997 and January 2002. Operator comments were gathered in 86 (70%) of the cases. The operator was, if possible, the most junior resident on the service. Thirty-nine operators participated in the survey. Efficacy, safety, and ease of use of the catheter were determined by operators' comments and ECG observations during the procedure. Corroborating clinical data were gathered from medical records. In 68 (79%) of the procedures that were commented upon, the operator described insertion into the pulmonary artery (PA) as easy; only 2 (2%) indicated difficulty in accessing the PA. In 41 (63%) of the bilateral angiograms that were commented upon, the operator described accessing the left PA from the right PA as easy; only 6 (9%) rated it as difficult and all were with an older technique in which the catheter was withdrawn to the pulmonary bifurcation without a wire or with only the soft tip of the wire in the pigtail and then rotated to the left main pulmonary artery. Thirty-one of the 41 patients who demonstrated premature ventricular contractions (PVCs) had a previous history of heart disease. Nineteen of the 39 patients who did not have PVCs had a history of heart disease (p = 0.018). The maneuverability and shape of the Hunter catheter make pulmonary angiography an easy procedure, even for operators with minimal experience and limited technical proficiency. PVCs demonstrated a statistically significant correlation with a positive patient history for cardiac disease, rather than being a universal risk.

  4. Safety and efficacy of transulnar approach for coronary angiography and intervention

    Institute of Scientific and Technical Information of China (English)

    LI Yun-zhi; NIE Bin; HAN Hong-ya; HU Bin; ZHOU Yu-jie; ZHAO Ying-xin; GUO Yong-he; LIU Yu-yang; SHI Dong-mei; WANG Zhi-jian; JIA De-an; YANG Shi-wei

    2010-01-01

    Background Transradial approach, which is now widely used in coronary angiography and intervention, may be advantageous with respect to the femoral access due to the lower incidence of vascular complications. Transulnar approach has been proposed for elective procedures in patients not suitable for transradial approach. The objective of this study was to evaluate the safety and efficacy of the transulnar approach versus the transradial approach for coronary angiography and intervention.Methods Two hundred and forty patients undergoing coronary angiography, followed or not by intervention, were randomized to transulnar (TUA) or transradial approach (TRA). Doppler ultrasound assessments of the forearm vessels were scheduled for all patients before procedures, 1 day and 30 days after procedures. The primary end point was access site vascular complications during hospitalization and 30 days follow-up. Major adverse cardiac events (MACE) as secondary end point was recorded till 30 days follow-up.Results Successful puncture was achieved in 98.3% (118/120) of patients in the TUA group, and in 100% (120/120) of patients in the TRA group. Coronary angiographies were performed in 40 and 39 patients in TUA and TRA group. Intervention procedures were performed in 78 and 83 patients in TUA and TRA group, respectively. The incidence of artery stenosis 1 day and 30 days after procedures was 11.0% vs. 12.3% and 5.1% vs. 6.6% in TUA and TRA group, respectively. Asymptomatic access site artery occlusion occurred in 5.1% vs.1.7% of patients 1 day and 30 days after transulnar angioplasty, and in 6.6% vs. 4.9% of patients 1 day and 30 days after transradial angioplasty. Minor bleeding was still observed at the moment of the ultrasound assessment in 5.9% and 5.7% of patients in TUA and TRA group, respectively (P=0.949). No big forearm hematoma, and A-V fistula were observed in both groups. Freedom from MACE at 30 days follow-up was observed in all patients.Conclusions The transulnar

  5. Transradial approach for coronary angiography and interventions in patients with coronary bypass grafts: tips and tricks.

    Science.gov (United States)

    Burzotta, Francesco; Trani, Carlo; Hamon, Martial; Amoroso, Giovanni; Kiemeneij, Ferdinand

    2008-08-01

    Among patients undergoing coronary procedures, patients with coronary artery bypass grafts represent an important, high risk subgroup. Routine transradial approach may be successfully adopted in these patients to reduce access-site complications. However, transradial cannulation of the grafts may result technically demanding. In this article we discuss the specific technical issues and we present a series of tips and tricks which may facilitate angiography and interventions on both internal mammary and aorto-coronary grafts.

  6. Computational hemodynamics of an implanted coronary stent based on three-dimensional cine angiography reconstruction.

    Science.gov (United States)

    Chen, Mounter C Y; Lu, Po-Chien; Chen, James S Y; Hwang, Ned H C

    2005-01-01

    Coronary stents are supportive wire meshes that keep narrow coronary arteries patent, reducing the risk of restenosis. Despite the common use of coronary stents, approximately 20-35% of them fail due to restenosis. Flow phenomena adjacent to the stent may contribute to restenosis. Three-dimensional computational fluid dynamics (CFD) and reconstruction based on biplane cine angiography were used to assess coronary geometry and volumetric blood flows. A patient-specific left anterior descending (LAD) artery was reconstructed from single-plane x-ray imaging. With corresponding electrocardiographic signals, images from the same time phase were selected from the angiograms for dynamic three-dimensional reconstruction. The resultant three-dimensional LAD artery at end-diastole was adopted for detailed analysis. Both the geometries and flow fields, based on a computational model from CAE software (ANSYS and CATIA) and full three-dimensional Navier-Stroke equations in the CFD-ACE+ software, respectively, changed dramatically after stent placement. Flow fields showed a complex three-dimensional spiral motion due to arterial tortuosity. The corresponding wall shear stresses, pressure gradient, and flow field all varied significantly after stent placement. Combined angiography and CFD techniques allow more detailed investigation of flow patterns in various segments. The implanted stent(s) may be quantitatively studied from the proposed hemodynamic modeling approach.

  7. Radiological management of blunt polytrauma with computed tomography and angiography: an integrated approach

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    Kurdziel, J.C.; Dondelinger, R.F.; Hemmer, M.

    1987-01-01

    107 polytraumatized patients, who had experienced blunt trauma have been worked up at admission with computed tomography of the thorax, abdomen and pelvis following computed tomography study of the brain: significant lesions were revealed in 98 (90%) patients. 79 (74%) patients showed trauma to the thorax, in 69 (64%) patients abdominal or pelvic trauma was evidenced. No false positive diagnosis was established. 5 traumatic findings were missed. Emergency angiography was indicated in 3 (3%) patients, following computed tomography examination. 3 other trauma patients were submitted directly to angiography without computed tomography examination during the time period this study was completed. Embolization was carried out in 5/6 patients. No thoracotomy was needed. 13 (12%) patients underwent laparotomy following computed tomography. Overall mortality during hospital stay was 14% (15/107). No patient died from visceral bleeding. Conservative management of blunt polytrauma patients can be advocated in almost 90% of visceral lesions. Computed tomography coupled with angiography and embolization represent an adequate integrated approach to the management of blunt polytrauma patients.

  8. Variable density sampling based on physically plausible gradient waveform. Application to 3D MRI angiography

    CERN Document Server

    Chauffert, Nicolas; Boucher, Marianne; Mériaux, Sébastien; CIUCIU, Philippe

    2015-01-01

    Performing k-space variable density sampling is a popular way of reducing scanning time in Magnetic Resonance Imaging (MRI). Unfortunately, given a sampling trajectory, it is not clear how to traverse it using gradient waveforms. In this paper, we actually show that existing methods [1, 2] can yield large traversal time if the trajectory contains high curvature areas. Therefore, we consider here a new method for gradient waveform design which is based on the projection of unrealistic initial trajectory onto the set of hardware constraints. Next, we show on realistic simulations that this algorithm allows implementing variable density trajectories resulting from the piecewise linear solution of the Travelling Salesman Problem in a reasonable time. Finally, we demonstrate the application of this approach to 2D MRI reconstruction and 3D angiography in the mouse brain.

  9. Angiography-based C-arm CT for the assessment of extrahepatic shunting before radioembolization

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    Heusner, Till Alexander; Hahn, S.; Forsting, M.; Antoch, G. [Inst. fuer Diagnostische und Interventionelle Radiologie und Neuroradiologie, Universitaetsklinik Essen (Germany); Hamami, M.E.; Poeppel, T.; Bockisch, A. [Klinik fuer Nuklearmedizin, Universitaetsklinik Essen (Germany); Ertle, J.; Hilgard, P. [Klinik fuer Gastroenterologie, Universitaetsklinik Essen (Germany)

    2010-07-15

    Purpose: to retrospectively assess the accuracy of angiography-based C-arm CT for the detection of extrahepatic shunting before SIRT. Materials and methods: 30 patients (mean age: 64 {+-} 12 years) with hypervascularized hepatic tumors underwent hepatic angiography, coil embolization of gastrointestinal collaterals and 99mTc-macroaggregated albumin (MAA) SPECT/CT before SIRT. Before MAA injection via a microcatheter from the intended treatment position, an angiography and angiography-based C-arm CT (XperCT trademark, Philips Healthcare) were acquired. Angiographies and XperCT trademark were performed from 48 microcatheter positions followed by MAA injections and MAA-SPECT/CT. MAA-SPECT/CT served as the reference standard for determining the accuracy of hepatic arteriography and C-arm CT for the detection of extrahepatic shunting. Results: MAA-SPECT/CT revealed extrahepatic shunting in 5 patients (17%). Hepatic arteriography yielded a true negative in 22 (73%), a false negative in 5 (17%), and an unclear result in 3 patients (10%). C-arm CT yielded a true positive in 3 (10%), true negative in 24 (80%), false positive in 1 (3%), and false negative in 2 patients (7%). The specificity and the NPV of hepatic arteriography for the detection of extrahepatic shunting were 88% and 81%, respectively. For C-arm CT the sensitivity, specificity, PPV, NPV, and accuracy for the detection of extrahepatic shunting were 60%, 96%, 75%, 92%, and 90%, respectively. Conclusion: C-arm CT offers additional information to angiography when assessing SIRT patients for extrahepatic shunting. More accurate detection of extrahepatic shunting may optimize the workflow in SIRT preparations by avoiding unnecessary repeat angiographies. (orig.)

  10. A meta-analysis of randomized controlled trials comparing left with right radial approach for coronary angiography

    Institute of Scientific and Technical Information of China (English)

    牛小伟

    2014-01-01

    Objective To compare the efficacy between left radial approach(LRA)and right radial approach(RRA)for coronary angiography(CAG).Methods The following databases were searched,including PubMed,Embase,Web of science,Cochrane Library,CBM,VIP,WAnfang databases and CNKI,from creation of database to January 2013.Two reviewers extracted data independent-

  11. Understanding phase contrast MR angiography a practical approach with Matlab examples

    CERN Document Server

    Suresh Paul, Joseph

    2016-01-01

    Providing many unique MATLAB codes and functions throughout, this book covers the basics of Magnetic Resonance Imaging (MRI), leading to an in-depth understanding of the concepts and tools required for analysis and interpretation of Phase Contrast MR Angiography (PC-MRA). The concept of PC-MRA is often difficult, but essential for practicing engineers and scientists working in MR related areas. The concepts are better understood by uniquely combining the physical principles of fluid flow and MR imaging, laid out by modeling the theory and applications using a commonly used software tool MATLAB®. The book starts with a detailed theory of PC-MRA followed by a description of various image processing methods, including detailed MATLAB codes used for their implementation. The flow concepts in the context of MR imaging are explained using MATLAB based simulations.

  12. Murine fundus fluorescein angiography: An alternative approach using a handheld camera.

    Science.gov (United States)

    Ehrenberg, Moshe; Ehrenberg, Scott; Schwob, Ouri; Benny, Ofra

    2016-07-01

    In today's modern pharmacologic approach to treating sight-threatening retinal vascular disorders, there is an increasing demand for a compact, mobile, lightweight and cost-effective fluorescein fundus camera to document the effects of antiangiogenic drugs on laser-induced choroidal neovascularization (CNV) in mice and other experimental animals. We have adapted the use of the Kowa Genesis Df Camera to perform Fundus Fluorescein Angiography (FFA) in mice. The 1 kg, 28 cm high camera has built-in barrier and exciter filters to allow digital FFA recording to a Compact Flash memory card. Furthermore, this handheld unit has a steady Indirect Lens Holder that firmly attaches to the main unit, that securely holds a 90 diopter lens in position, in order to facilitate appropriate focus and stability, for photographing the delicate central murine fundus. This easily portable fundus fluorescein camera can effectively record exceptional central retinal vascular detail in murine laser-induced CNV, while readily allowing the investigator to adjust the camera's position according to the variable head and eye movements that can randomly occur while the mouse is optimally anesthetized. This movable image recording device, with efficiencies of space, time, cost, energy and personnel, has enabled us to accurately document the alterations in the central choroidal and retinal vasculature following induction of CNV, implemented by argon-green laser photocoagulation and disruption of Bruch's Membrane, in the experimental murine model of exudative macular degeneration.

  13. Learning-based automatic detection of severe coronary stenoses in CT angiographies

    Science.gov (United States)

    Melki, Imen; Cardon, Cyril; Gogin, Nicolas; Talbot, Hugues; Najman, Laurent

    2014-03-01

    3D cardiac computed tomography angiography (CCTA) is becoming a standard routine for non-invasive heart diseases diagnosis. Thanks to its high negative predictive value, CCTA is increasingly used to decide whether or not the patient should be considered for invasive angiography. However, an accurate assessment of cardiac lesions using this modality is still a time consuming task and needs a high degree of clinical expertise. Thus, providing automatic tool to assist clinicians during the diagnosis task is highly desirable. In this work, we propose a fully automatic approach for accurate severe cardiac stenoses detection. Our algorithm uses the Random Forest classi cation to detect stenotic areas. First, the classi er is trained on 18 CT cardiac exams with CTA reference standard. Then, then classi cation result is used to detect severe stenoses (with a narrowing degree higher than 50%) in a 30 cardiac CT exam database. Features that best captures the di erent stenoses con guration are extracted along the vessel centerlines at di erent scales. To ensure the accuracy against the vessel direction and scale changes, we extract features inside cylindrical patterns with variable directions and radii. Thus, we make sure that the ROIs contains only the vessel walls. The algorithm is evaluated using the Rotterdam Coronary Artery Stenoses Detection and Quantication Evaluation Framework. The evaluation is performed using reference standard quanti cations obtained from quantitative coronary angiography (QCA) and consensus reading of CTA. The obtained results show that we can reliably detect severe stenosis with a sensitivity of 64%.

  14. Catheter Angiography

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    Full Text Available ... spaghetti. top of page How does the procedure work? Catheter angiography works much the same as a ... iodine. If angiography is essential, a variety of methods is used to decrease risk of allergy: You ...

  15. Classification-based summation of cerebral digital subtraction angiography series for image post-processing algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Schuldhaus, D; Spiegel, M; Polyanskaya, M; Hornegger, J [Pattern Recognition Lab, University Erlangen-Nuremberg (Germany); Redel, T [Siemens AG Healthcare Sector, Forchheim (Germany); Struffert, T; Doerfler, A, E-mail: martin.spiegel@informatik.uni-erlangen.de [Department of Neuroradiology, University Erlangen-Nuremberg (Germany)

    2011-03-21

    X-ray-based 2D digital subtraction angiography (DSA) plays a major role in the diagnosis, treatment planning and assessment of cerebrovascular disease, i.e. aneurysms, arteriovenous malformations and intracranial stenosis. DSA information is increasingly used for secondary image post-processing such as vessel segmentation, registration and comparison to hemodynamic calculation using computational fluid dynamics. Depending on the amount of injected contrast agent and the duration of injection, these DSA series may not exhibit one single DSA image showing the entire vessel tree. The interesting information for these algorithms, however, is usually depicted within a few images. If these images would be combined into one image the complexity of segmentation or registration methods using DSA series would drastically decrease. In this paper, we propose a novel method automatically splitting a DSA series into three parts, i.e. mask, arterial and parenchymal phase, to provide one final image showing all important vessels with less noise and moving artifacts. This final image covers all arterial phase images, either by image summation or by taking the minimum intensities. The phase classification is done by a two-step approach. The mask/arterial phase border is determined by a Perceptron-based method trained from a set of DSA series. The arterial/parenchymal phase border is specified by a threshold-based method. The evaluation of the proposed method is two-sided: (1) comparison between automatic and medical expert-based phase selection and (2) the quality of the final image is measured by gradient magnitudes inside the vessels and signal-to-noise (SNR) outside. Experimental results show a match between expert and automatic phase separation of 93%/50% and an average SNR increase of up to 182% compared to summing up the entire series.

  16. Classification-based summation of cerebral digital subtraction angiography series for image post-processing algorithms

    Science.gov (United States)

    Schuldhaus, D.; Spiegel, M.; Redel, T.; Polyanskaya, M.; Struffert, T.; Hornegger, J.; Doerfler, A.

    2011-03-01

    X-ray-based 2D digital subtraction angiography (DSA) plays a major role in the diagnosis, treatment planning and assessment of cerebrovascular disease, i.e. aneurysms, arteriovenous malformations and intracranial stenosis. DSA information is increasingly used for secondary image post-processing such as vessel segmentation, registration and comparison to hemodynamic calculation using computational fluid dynamics. Depending on the amount of injected contrast agent and the duration of injection, these DSA series may not exhibit one single DSA image showing the entire vessel tree. The interesting information for these algorithms, however, is usually depicted within a few images. If these images would be combined into one image the complexity of segmentation or registration methods using DSA series would drastically decrease. In this paper, we propose a novel method automatically splitting a DSA series into three parts, i.e. mask, arterial and parenchymal phase, to provide one final image showing all important vessels with less noise and moving artifacts. This final image covers all arterial phase images, either by image summation or by taking the minimum intensities. The phase classification is done by a two-step approach. The mask/arterial phase border is determined by a Perceptron-based method trained from a set of DSA series. The arterial/parenchymal phase border is specified by a threshold-based method. The evaluation of the proposed method is two-sided: (1) comparison between automatic and medical expert-based phase selection and (2) the quality of the final image is measured by gradient magnitudes inside the vessels and signal-to-noise (SNR) outside. Experimental results show a match between expert and automatic phase separation of 93%/50% and an average SNR increase of up to 182% compared to summing up the entire series.

  17. Classification-based summation of cerebral digital subtraction angiography series for image post-processing algorithms.

    Science.gov (United States)

    Schuldhaus, D; Spiegel, M; Redel, T; Polyanskaya, M; Struffert, T; Hornegger, J; Doerfler, A

    2011-03-21

    X-ray-based 2D digital subtraction angiography (DSA) plays a major role in the diagnosis, treatment planning and assessment of cerebrovascular disease, i.e. aneurysms, arteriovenous malformations and intracranial stenosis. DSA information is increasingly used for secondary image post-processing such as vessel segmentation, registration and comparison to hemodynamic calculation using computational fluid dynamics. Depending on the amount of injected contrast agent and the duration of injection, these DSA series may not exhibit one single DSA image showing the entire vessel tree. The interesting information for these algorithms, however, is usually depicted within a few images. If these images would be combined into one image the complexity of segmentation or registration methods using DSA series would drastically decrease. In this paper, we propose a novel method automatically splitting a DSA series into three parts, i.e. mask, arterial and parenchymal phase, to provide one final image showing all important vessels with less noise and moving artifacts. This final image covers all arterial phase images, either by image summation or by taking the minimum intensities. The phase classification is done by a two-step approach. The mask/arterial phase border is determined by a Perceptron-based method trained from a set of DSA series. The arterial/parenchymal phase border is specified by a threshold-based method. The evaluation of the proposed method is two-sided: (1) comparison between automatic and medical expert-based phase selection and (2) the quality of the final image is measured by gradient magnitudes inside the vessels and signal-to-noise (SNR) outside. Experimental results show a match between expert and automatic phase separation of 93%/50% and an average SNR increase of up to 182% compared to summing up the entire series.

  18. Advantages of a workbench reshaped AR1 mod catheter for right coronary angiography by right radial approach.

    Science.gov (United States)

    Baldi, Cesare; Mirra, Marco; Di Maio, Marco; Attisano, Tiziana; Di Muro, Michele Roberto; Vigorito, Francesco; Farina, Rosario; Polito, Maria Vincenza; Giudice, Pietro; Piscione, Federico

    2014-03-01

    Transradial approach in cardiac catheterization is increasing. In daily practice, coronary angiography via radial artery is usually performed by using catheters designed for femoral approach. The aim of this study was to evaluate advantages in the use of a workbench reshaped AR1 mod catheter, in terms of procedural duration time, number of catheters per procedure, fluoroscopy time, contrast agent administered volume, images quality and costs. Two hundred patients, submitted to coronary angiography via right radial artery in our institution, have been retrospectively reviewed. Patients have been divided in two groups, depending on whether a workbench reshaped Cordis Amplatz AR1 mod catheter (rAR1 mod), or catheters in their original shape (OC) have been employed. In the rAR1 mod group (100 patients) a lower number of catheters per procedure (1.07 ± 0.25 vs. 1.47 ± 1.65; p right coronary selective engagement (76.76% vs. 53.12%; p right coronary angiography via right radial approach is performed, the utilization of rAR1 mod catheter correlates with multiple advantages in terms of procedural parameters.

  19. The Use of an Upper-limb-artery Approach and Long Sheaths in Splanchnic Angiography and Interventional Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Shimohira, Masashi; Ogino, Hiroyuki; Mori, Yuji; Shibamoto, Yuta (Dept. of Radiology, Nagoya City Univ. Graduate School of Medical Sciences, Nagoya (Japan)); Omiya, Hiroko; Suzuki, Hirochika (Dept. of Radiology, Tsushima City Hospital, Tsushima (Japan))

    2009-08-15

    Background: The prolonged bed-rest required achieving hemostasis after splanchnic angiography and interventional procedures can be avoided if the upper limb arteries are used. In such procedures, the use of long sheaths capable of reaching the descending aorta may be advantageous. Purpose: To analyze the results of procedures that utilizes an upper-limb-artery approach and long sheaths. Material and Methods: Two hundred forty-two patients with a mean age of 64 years underwent splanchnic angiography and interventional procedures via an upper limb artery using a long sheath (85 cm, 4-French). Repeat examinations were performed on 48 patients and the total number of examinations was 296. The records of these 296 examinations were reviewed and the success rate and complications were evaluated. Results: Overall, 295 of 296 (99.7%) examinations were successful, and one (0.3%) failed. Complications and side effects occurred in six cases (2.0%), a painful sheath manipulation occurred in two examinations (0.7%), and arterial occlusion (including temporary occlusion), hematoma of the puncture site, and pseudoaneurysm occurred in two (0.7%), one (0.3%), and one (0.3%) patient, respectively. Conclusion: The use of a long sheath capable of reaching the descending aorta enables the performance of splanchnic angiography and interventional procedures via the upper limb arteries

  20. Catheter Angiography

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Catheter Angiography? Angiography is a minimally invasive medical test that helps physicians diagnose and treat medical conditions. ...

  1. Catheter Angiography

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    Full Text Available ... medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ... a tendency to bleed. top of page Additional Information and Resources Society of Interventional Radiology (SIR) - Patient ...

  2. Catheter Angiography

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    Full Text Available ... with you. top of page What are the benefits vs. risks? Benefits Angiography may eliminate the need for surgery. If ... cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk. ...

  3. Catheter Angiography

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    Full Text Available ... injection of contrast material to examine blood vessels in key areas of the body for abnormalities such ... makes it possible to combine diagnosis and treatment in a single procedure. Catheter angiography produces very detailed, ...

  4. Catheter Angiography

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    Full Text Available ... of page What are some common uses of the procedure? Catheter angiography is used to examine blood ... an hour away. top of page What does the equipment look like? The equipment typically used for ...

  5. Reconstructions with identical filling (RIF) of the heart: a physiological approach to image reconstruction in coronary CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Reinartz, S.D.; Diefenbach, B.S.; Kuhl, C.K.; Mahnken, A.H. [University Hospital, RWTH Aachen University, Department of Diagnostic and Interventional Radiology, Aachen (Germany); Allmendinger, T. [Siemens Healthcare Sector, Department of Computed Tomography, Forchheim (Germany)

    2012-12-15

    To compare image quality in coronary artery computed tomography angiography (cCTA) using reconstructions with automated phase detection and Reconstructions computed with Identical Filling of the heart (RIF). Seventy-four patients underwent ECG-gated dual source CT (DSCT) between November 2009 and July 2010 for suspected coronary heart disease (n = 35), planning of transcatheter aortic valve replacement (n = 34) or evaluation of ventricular function (n = 5). Image data sets by the RIF formula and automated phase detection were computed and evaluated with the AHA 15-segment model and a 5-grade Likert scale (1: poor, 5: excellent quality). Subgroups regarding rhythm (sinus rhythm = SR; arrhythmia = ARR) and potential premedication were evaluated by a per-segment, per-vessel and per-patient analysis. RIF significantly improved image quality in 10 of 15 coronary segments (P < 0.05). More diagnostic segments were provided by RIF regarding the entire cohort (n = 693 vs. 590, P < 0.001) and all of the subgroups (e.g. ARR: n = 143 vs. 72, P < 0.001). In arrhythmic patients (n = 19), more diagnostic vessels (e.g. LAD: n = 10 vs. 3; P < 0.014) and complete data sets (n = 7 vs. 1; P < 0.001) were produced. RIF reconstruction is superior to automatic diastolic non-edited reconstructions, especially in arrhythmic patients. RIF theory provides a physiological approach for determining the optimal image reconstruction point in ECG-gated CT angiography. (orig.)

  6. [Affine transformation-based automatic registration for peripheral digital subtraction angiography (DSA)].

    Science.gov (United States)

    Kong, Gang; Dai, Dao-Qing; Zou, Lu-Min

    2008-07-01

    In order to remove the artifacts of peripheral digital subtraction angiography (DSA), an affine transformation-based automatic image registration algorithm is introduced here. The whole process is described as follows: First, rectangle feature templates are constructed with their centers of the extracted Harris corners in the mask, and motion vectors of the central feature points are estimated using template matching technology with the similarity measure of maximum histogram energy. And then the optimal parameters of the affine transformation are calculated with the matrix singular value decomposition (SVD) method. Finally, bilinear intensity interpolation is taken to the mask according to the specific affine transformation. More than 30 peripheral DSA registrations are performed with the presented algorithm, and as the result, moving artifacts of the images are removed with sub-pixel precision, and the time consumption is less enough to satisfy the clinical requirements. Experimental results show the efficiency and robustness of the algorithm.

  7. Catheter Angiography

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    Full Text Available ... E-mail: Area code: Phone no: Thank you! Images × Image Gallery Interventional radiologist performing an angiography exam View ... address): From (your name): Your e-mail address: Personal message (optional): Bees: Wax: Notice: RadiologyInfo respects your ...

  8. Improved signal-to-noise ratio in parallel coronary artery magnetic resonance angiography using graph cuts based Bayesian reconstruction.

    Science.gov (United States)

    Singh, Gurmeet; Nguyen, Thanh; Kressler, Bryan; Spincemaille, Pascal; Raj, Ashish; Zabih, Ramin; Wang, Yi

    2006-01-01

    High resolution 3D coronary artery MR angiography is time-consuming and can benefit from accelerated data acquisition provided by parallel imaging techniques without sacrificing spatial resolution. Currently, popular maximum likelihood based parallel imaging reconstruction techniques such as the SENSE algorithm offer this advantage at the cost of reduced signal-to-noise ratio (SNR). Maximum a posteriori (MAP) reconstruction techniques that incorporate globally smooth priors have been developed to recover this SNR loss, but they tend to blur sharp edges in the target image. The objective of this study is to demonstrate the feasibility of employing edge-preserving Markov random field priors in a MAP reconstruction framework, which can be solved efficiently using a graph cuts based optimization algorithm. The preliminary human study shows that our reconstruction provides significantly better SNR than the SENSE reconstruction performed by a commercially available scanner for navigator gated steady state free precession 3D coronary magnetic resonance angiography images (n = 4).

  9. Coronary stent on coronary CT angiography: Assessment with model-based iterative reconstruction technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Chae; Kim, Yeo Koon; Chun, Eun Ju; Choi, Sang IL [Dept. of of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of)

    2016-05-15

    To assess the performance of model-based iterative reconstruction (MBIR) technique for evaluation of coronary artery stents on coronary CT angiography (CCTA). Twenty-two patients with coronary stent implantation who underwent CCTA were retrospectively enrolled for comparison of image quality between filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and MBIR. In each data set, image noise was measured as the standard deviation of the measured attenuation units within circular regions of interest in the ascending aorta (AA) and left main coronary artery (LM). To objectively assess the noise and blooming artifacts in coronary stent, we additionally measured the standard deviation of the measured attenuation and intra-luminal stent diameters of total 35 stents with dedicated software. All image noise measured in the AA (all p < 0.001), LM (p < 0.001, p = 0.001) and coronary stent (all p < 0.001) were significantly lower with MBIR in comparison to those with FBP or ASIR. Intraluminal stent diameter was significantly higher with MBIR, as compared with ASIR or FBP (p < 0.001, p = 0.001). MBIR can reduce image noise and blooming artifact from the stent, leading to better in-stent assessment in patients with coronary artery stent.

  10. Swept-source OCT Angiography of the Retinal Vasculature using Intensity Differentiation Based OMAG Algorithms

    Science.gov (United States)

    Huang, Yanping; Zhang, Qinqin; Thorell, Mariana Rossi; An, Lin; Durbin, Mary; Laron, Michal; Sharma, Utkarsh; Gregori, Giovanni; Rosenfeld, Philip J.; Wang, Ruikang K

    2014-01-01

    Background and Objective To demonstrate the feasibility of using a 1050 nm swept-source OCT (SS-OCT) system to achieve noninvasive retinal vasculature imaging in human eyes. Materials and Methods Volumetric datasets were acquired using a ZEISS 1 µm SS-OCT prototype that operated at an A-line rate of 100 kHz. A scanning protocol designed to allow for motion contrast processing, referred to as OCT angiography or optical microangiography (OMAG), was used to scan ~3 mm × 3 mm area in the central macular region of the retina within ~4.5 seconds. Intensity differentiation based OMAG algorithm was used to extract 3-D retinal functional microvasculature information. Results Intensity signal differentiation generated capillary-level resolution en face OMAG images of the retina. The parafoveal capillaries were clearly visible, thereby allowing visualization of the foveal avascular zone (FAZ) in normal subjects. Conclusion The capability of OMAG to produce retinal vascular images was demonstrated using the ZEISS 1 µm SS-OCT prototype. This technique can potentially have clinical value for studying retinal vasculature abnormalities. PMID:25230403

  11. An automatic fuzzy-based multi-temporal brain digital subtraction angiography image fusion algorithm using curvelet transform and content selection strategy.

    Science.gov (United States)

    Momeni, Saba; Pourghassem, Hossein

    2014-08-01

    Recently image fusion has prominent role in medical image processing and is useful to diagnose and treat many diseases. Digital subtraction angiography is one of the most applicable imaging to diagnose brain vascular diseases and radiosurgery of brain. This paper proposes an automatic fuzzy-based multi-temporal fusion algorithm for 2-D digital subtraction angiography images. In this algorithm, for blood vessel map extraction, the valuable frames of brain angiography video are automatically determined to form the digital subtraction angiography images based on a novel definition of vessel dispersion generated by injected contrast material. Our proposed fusion scheme contains different fusion methods for high and low frequency contents based on the coefficient characteristic of wrapping second generation of curvelet transform and a novel content selection strategy. Our proposed content selection strategy is defined based on sample correlation of the curvelet transform coefficients. In our proposed fuzzy-based fusion scheme, the selection of curvelet coefficients are optimized by applying weighted averaging and maximum selection rules for the high frequency coefficients. For low frequency coefficients, the maximum selection rule based on local energy criterion is applied to better visual perception. Our proposed fusion algorithm is evaluated on a perfect brain angiography image dataset consisting of one hundred 2-D internal carotid rotational angiography videos. The obtained results demonstrate the effectiveness and efficiency of our proposed fusion algorithm in comparison with common and basic fusion algorithms.

  12. Carotid angiography

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    Arne Torkildsen

    1950-03-01

    Full Text Available After a brief review of the history of cerebral angiography, some of the most important points concerning the percutaneous angiographic technique have been described. The value of the angiographic examination in cases of cerebral gliomas has been studied, based upon a consecutive series of 127 verified cases of hemispherical gliomas. Of 31 cases of frontal glioma, 28 could be diagnosed by the angiographic method; of 33 cases of parietal glioma, the angiograms revealed the neoplasm in 27 instances; of 39 cases of temporal glioma, the tumor could be localized in 38 cases; of 13 cases of occipital glioma, the angiographic localization of the tumor was successfull in 9 instances; of 11. cases of glioma infiltrating the corpus callosum and (or the basal ganglia, the angiographic examination was successful in only 3 cases. The angiographic examination in cases of cerebral glioma, in my experience, yields a more satisfactory result as to the localization than does the pneumography. The only exception concerns the gliomas growing in the thalamus or in the basal ganglia. These are more easily localized by means of ventriculography. As to the differential diagnosis of the gliomas, tumor vessels could, be seen both in astrocytomas and in glioblastomas. Most cases of astrocytomas were however devoid of specific tumor vessels. When present they could not be definitely distinguished from those seen in glioblastomas, but the abnormal findings were far less numerous and definitely less pronounced in astrocytomas than in glioblastomas. In most cases the astrocytomas were characterized only by displacement of blood vessels of normal appearance, while the glioblastomas frequently-presented both displacement of normal appearing blood vessels and new formed blood vessels within the neoplasm itself. The pathological blood vessels in the tumor were frequently abnormal both regarding their topographical appearance and their type. Frequent findings were arterio

  13. CT coronary angiography vs. invasive coronary angiography in CHD

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    Anja Hagen

    2012-04-01

    Full Text Available Scientific background: Various diagnostic tests including conventional invasive coronary angiography and non-invasive computed tomography (CT coronary angiography are used in the diagnosis of coronary heart disease (CHD. Research questions: The present report aims to evaluate the clinical efficacy, diagnostic accuracy, prognostic value cost-effectiveness as well as the ethical, social and legal implications of CT coronary angiography versus invasive coronary angiography in the diagnosis of CHD. Methods: A systematic literature search was conducted in electronic data bases (MEDLINE, EMBASE etc. in October 2010 and was completed with a manual search. The literature search was restricted to articles published from 2006 in German or English. Two independent reviewers were involved in the selection of the relevant publications. The medical evaluation was based on systematic reviews of diagnostic studies with invasive coronary angiography as the reference standard and on diagnostic studies with intracoronary pressure measurement as the reference standard. Study results were combined in a meta-analysis with 95 % confidence intervals (CI. Additionally, data on radiation doses from current non-systematic reviews were taken into account. A health economic evaluation was performed by modelling from the social perspective with clinical assumptions derived from the meta-analysis and economic assumptions derived from contemporary German sources. Data on special indications (bypass or in-stent-restenosis were not included in the evaluation. Only data obtained using CT scanners with at least 64 slices were considered. Results: No studies were found regarding the clinical efficacy or prognostic value of CT coronary angiography versus conventional invasive coronary angiography in the diagnosis of CHD. Overall, 15 systematic reviews with data from 44 diagnostic studies using invasive coronary angiography as the reference standard (identification of obstructive

  14. Alternative diagnoses based on CT angiography of the chest in patients with suspected pulmonary thromboembolism

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Eleci Vaz; Gazzana, Marcelo Basso; Seligman, Renato; Knorst, Marli Maria, E-mail: mknorst@gmail.com [Hospital de Clinicas de Porto Alegre, Porto Alegre, RS (Brazil); Guerra, Vinicius Andre [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Faculdade de Medicina. Programa de Pos-Graduacao em Ciencias Pneumologicas; Sarmento, Muriel Bossle; Guazzelli, Pedro Arends; Hoffmeister, Mariana Costa [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre (Brazil). Faculdade de Medicina

    2016-01-15

    Objective: To determine the prevalence of alternative diagnoses based on chest CT angiography (CTA) in patients with suspected pulmonary thromboembolism (PTE) who tested negative for PTE, as well as whether those alternative diagnoses had been considered prior to the CTA. Methods: This was a cross-sectional, retrospective study involving 191 adult patients undergoing CTA for suspected PTE between September of 2009 and May of 2012. Chest X-rays and CTAs were reviewed to determine whether the findings suggested an alternative diagnosis in the cases not diagnosed as PTE. Data on symptoms, risk factors, comorbidities, length of hospital stay, and mortality were collected. Results: On the basis of the CTA findings, PTE was diagnosed in 47 cases (24.6%). Among the 144 patients not diagnosed with PTE via CTA, the findings were abnormal in 120 (83.3%). Such findings were consistent with an alternative diagnosis that explained the symptoms in 75 patients (39.3%). Among those 75 cases, there were only 39 (20.4%) in which the same alterations had not been previously detected on chest X-rays. The most common alternative diagnosis, made solely on the basis of the CTA findings, was pneumonia (identified in 20 cases). Symptoms, risk factors, comorbidities, and the in-hospital mortality rate did not differ significantly between the patients with and without PTE. However, the median hospital stay was significantly longer in the patients with PTE than in those without (18.0 and 9.5 days, respectively; p = 0.001). Conclusions: Our results indicate that chest CTA is useful in cases of suspected PTE, because it can confirm the diagnosis and reveal findings consistent with an alternative diagnosis in a significant number of patients. (author)

  15. Alternative diagnoses based on CT angiography of the chest in patients with suspected pulmonary thromboembolism

    Science.gov (United States)

    Ferreira, Eleci Vaz; Gazzana, Marcelo Basso; Sarmento, Muriel Bossle; Guazzelli, Pedro Arends; Hoffmeister, Mariana Costa; Guerra, Vinicius André; Seligman, Renato; Knorst, Marli Maria

    2016-01-01

    Objective : To determine the prevalence of alternative diagnoses based on chest CT angiography (CTA) in patients with suspected pulmonary thromboembolism (PTE) who tested negative for PTE, as well as whether those alternative diagnoses had been considered prior to the CTA. Methods : This was a cross-sectional, retrospective study involving 191 adult patients undergoing CTA for suspected PTE between September of 2009 and May of 2012. Chest X-rays and CTAs were reviewed to determine whether the findings suggested an alternative diagnosis in the cases not diagnosed as PTE. Data on symptoms, risk factors, comorbidities, length of hospital stay, and mortality were collected. Results : On the basis of the CTA findings, PTE was diagnosed in 47 cases (24.6%). Among the 144 patients not diagnosed with PTE via CTA, the findings were abnormal in 120 (83.3%). Such findings were consistent with an alternative diagnosis that explained the symptoms in 75 patients (39.3%). Among those 75 cases, there were only 39 (20.4%) in which the same alterations had not been previously detected on chest X-rays. The most common alternative diagnosis, made solely on the basis of the CTA findings, was pneumonia (identified in 20 cases). Symptoms, risk factors, comorbidities, and the in-hospital mortality rate did not differ significantly between the patients with and without PTE. However, the median hospital stay was significantly longer in the patients with PTE than in those without (18.0 and 9.5 days, respectively; p = 0.001). Conclusions : Our results indicate that chest CTA is useful in cases of suspected PTE, because it can confirm the diagnosis and reveal findings consistent with an alternative diagnosis in a significant number of patients. PMID:26982039

  16. Alternative diagnoses based on CT angiography of the chest in patients with suspected pulmonary thromboembolism

    Directory of Open Access Journals (Sweden)

    Eleci Vaz Ferreira

    2016-02-01

    Full Text Available Objective : To determine the prevalence of alternative diagnoses based on chest CT angiography (CTA in patients with suspected pulmonary thromboembolism (PTE who tested negative for PTE, as well as whether those alternative diagnoses had been considered prior to the CTA. Methods : This was a cross-sectional, retrospective study involving 191 adult patients undergoing CTA for suspected PTE between September of 2009 and May of 2012. Chest X-rays and CTAs were reviewed to determine whether the findings suggested an alternative diagnosis in the cases not diagnosed as PTE. Data on symptoms, risk factors, comorbidities, length of hospital stay, and mortality were collected. Results : On the basis of the CTA findings, PTE was diagnosed in 47 cases (24.6%. Among the 144 patients not diagnosed with PTE via CTA, the findings were abnormal in 120 (83.3%. Such findings were consistent with an alternative diagnosis that explained the symptoms in 75 patients (39.3%. Among those 75 cases, there were only 39 (20.4% in which the same alterations had not been previously detected on chest X-rays. The most common alternative diagnosis, made solely on the basis of the CTA findings, was pneumonia (identified in 20 cases. Symptoms, risk factors, comorbidities, and the in-hospital mortality rate did not differ significantly between the patients with and without PTE. However, the median hospital stay was significantly longer in the patients with PTE than in those without (18.0 and 9.5 days, respectively; p = 0.001. Conclusions : Our results indicate that chest CTA is useful in cases of suspected PTE, because it can confirm the diagnosis and reveal findings consistent with an alternative diagnosis in a significant number of patients.

  17. Value of color Doppler ultrasound in examining angiography approach before transradial cornary angiography%彩超探查经桡动脉冠状动脉造影入路的应用价值

    Institute of Scientific and Technical Information of China (English)

    封淑文; 于华; 黄建新; 王京

    2015-01-01

    目的:评价彩超探查经桡动脉途径冠状动脉造影( transradial coronary angiography , TRA )入路的应用价值。方法择期行经桡动脉冠状动脉造影患者400例,随机分为术前彩色多普勒超声检查组(实验组)和非多普勒超声检查组(对照组),各200例。主要评价指标包括造影成功率、造影时间、不同直径造影鞘管使用率、术中及术后不良事件(如死亡、急性心肌梗死、局部血肿、假性动脉瘤、骨筋膜室综合征和桡动脉闭塞);次要评价指标包括桡动脉内径、超声下入路解剖变异发生率。结果实验组造影成功率(100%)较对照组(90%)高,但差异无统计学意义(P>0.05)。实验组造影时间比对照组缩短[(10.7±1.0)min vs (12.5±3.5)min,P<0.05]。实验组血管并发症发生率显著低于对照组;两组均未发生死亡、假性动脉瘤、桡动脉闭塞及骨筋膜室综合征。结论 TRA前应用彩超探查造影入路可提高造影成功率,缩短造影时间,减少术中桡动脉痉挛及术后局部并发症。%Objective To explore the value of Color Doppler ultrasound in examining angiography access before transradial coronary angiography ( TRA) .Methods Four hundred consecutive patients undergoing elective transradial cornary angiography were screened.They were randomly divided into ultrasound group (200 cases) and conventional group without ultrasound examination (200 cases).The primary endpoints included success rate , percentage of angiographic catheter use with different diameters ,adverse events during and after the procedure ( such as death , acute myocardial infarction , upper limb haematoma , osteofascial compartment syn-drome ,radial artery pseudoaneurysm or occlusion );the secondary endpoints were the average diameter of radial and anatomic variations of approach.Results The procedural success rates in the study group and conventional

  18. A practical approach for a patient-tailored dose protocol in coronary CT angiography using prospective ECG triggering

    NARCIS (Netherlands)

    Dijk, van J.D.; Huizing, E.D.; Jager, P.L.; Ottervanger, J.P.; Knollema, S.; Slump, C.H.; Dalen, van J.A.

    2015-01-01

    To derive and validate a practical patient-specific dose protocol to obtain an image quality, expressed by the image noise, independent of patients’ size and a better radiation dose justification in coronary CT angiography (CCTA) using prospective ECG triggering. 43 patients underwent clinically ind

  19. Quantification of the myocardial area at risk using coronary CT angiography and Voronoi algorithm-based myocardial segmentation

    Energy Technology Data Exchange (ETDEWEB)

    Kurata, Akira; Kono, Atsushi; Coenen, Adriaan; Saru-Chelu, Raluca G.; Krestin, Gabriel P. [Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands); Sakamoto, Tsuyoshi [AZE inc, Development Division, Chiyoda, Tokyo (Japan); Kido, Teruhito; Mochizuki, Teruhito [Ehime University Graduate School of Medicine, Department of Radiology, Toon, Ehime (Japan); Higashino, Hiroshi [Yotsuba Circulation Clinic, Department of Radiology, Matsuyama, Ehime (Japan); Abe, Mitsunori [Yotsuba Circulation Clinic, Department of Cardiology, Matsuyama, Ehime (Japan); Feyter, Pim J. de; Nieman, Koen [Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands); Erasmus University Medical Center, Department of Cardiology, Rotterdam (Netherlands)

    2015-01-15

    The purpose of this study was to estimate the myocardial area at risk (MAAR) using coronary computed tomography angiography (CTA) and Voronoi algorithm-based myocardial segmentation in comparison with single-photon emission computed tomography (SPECT). Thirty-four patients with coronary artery disease underwent 128-slice coronary CTA, stress/rest thallium-201 SPECT, and coronary angiography (CAG). CTA-based MAAR was defined as the sum of all CAG stenosis (>50 %) related territories (the ratio of the left ventricular volume). Using automated quantification software (17-segment model, 5-point scale), SPECT-based MAAR was defined as the number of segments with a score above zero as compared to the total 17 segments by summed stress score (SSS), difference (SDS) score map, and comprehensive SPECT interpretation with either SSS or SDS best correlating CAG findings (SSS/SDS). Results were compared using Pearson's correlation coefficient. Forty-nine stenoses were observed in 102 major coronary territories. Mean value of CTA-based MAAR was 28.3 ± 14.0 %. SSS-based, SDS-based, and SSS/SDS-based MAAR was 30.1 ± 6.1 %, 20.1 ± 15.8 %, and 26.8 ± 15.7 %, respectively. CTA-based MAAR was significantly related to SPECT-based MAAR (r = 0.531 for SSS; r = 0.494 for SDS; r = 0.814 for SSS/SDS; P < 0.05 in each). CTA-based Voronoi algorithm myocardial segmentation reliably quantifies SPECT-based MAAR. (orig.)

  20. Carotid-anterior cerebral artery anastomosis on MR angiography: a university hospital-based study

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, Akira; Saito, Naoko; Okada, Yoshitaka; Inoue, Kaiji [Saitama Medical University International Medical Center, Department of Diagnostic Radiology, Hidaka, Saitama (Japan)

    2012-01-15

    Rarely in the anterior circulation, an anastomosis of the carotid and anterior cerebral arteries occurs when an anomalous branch arises from the ophthalmic segment of the internal carotid artery and anastomoses with the A1-A2 junction of the anterior communicating artery. Right-side predominance is known. To our knowledge, the incidence of carotid-anterior cerebral artery anastomosis has not been reported, so we researched cases in our institution records to determine incidence and investigated characteristic features of the condition on magnetic resonance (MR) angiography. To isolate such cases, we retrospectively reviewed cranial MR angiographic images of 3,491 consecutive patients in our institution. We found three cases with carotid-anterior cerebral artery anastomosis (two men, one woman), representing an incidence of 0.086%. The anastomosis was on the right in all three cases. A normal A1 segment of the anterior cerebral artery (ACA) was present in two cases but could not be identified in the remaining case on MR angiographic images that included source images. Two of the three patients demonstrated associated arterial variations in their carotid systems. On MR angiography, we observed a 0.086% incidence of carotid-anterior cerebral artery anastomosis in our institution and reaffirmed the right-side predominance of this anomaly. We found a high frequency of other associated arterial variations in the carotid system. (orig.)

  1. MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Miki, Hitoshi; Hamamoto, Ken (Ehime Univ., Shigenobu (Japan). School of Medicine)

    1994-01-01

    As the result of the application of the recently developed MR techniques, the diagnosis of the morphology and the function has been possible. MR angiography (MRA) is one of these new techniques, and provides vascular anatomy and hemodynamics. At present, there is the limitation in the indication of MRA for pediatric cerebral vascular diseases. However, the frequency of clinical application of MRA is expected to increase by rapidly progressed MR techniques. Of these MRA, time-of flight (TOF) MRA, and phase contrast (PC) MRA are now being examined clinically as main MRA methods for evaluating cerebrovascular diseases, such as Moyamoya disease, arteriovenous malformation, and cerebral aneurysm. During our study, 2D and 3D TOF MRA, and 2D PC and 3D PC MRA were performed for evaluating cerebrovascular diseases. The purpose of this paper is to explain the methods of these MRA, and clinical indications of MRA by showing representative clinical cases of cerebrovascular diseases. We consider that MRA ia a useful method for detecting and following-up pediatric cerebrovascular diseases at present time. It is necessary for radiologists to know the basis and clinical indications of MRA. (author).

  2. Placing two parallel catheters by Seldinger`s approach through the femoral artery for CT angiography and CT during arterioportography. Evaluation of efficacy and safety

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kazuhiro; Goto, Yasuyuki; Saito, Toshitaka [Musashino Red Cross Hospital, Tokyo (Japan); Wakabayashi, Yukari; Abe, Kimihiko

    1998-02-01

    The purpose of this study was to evaluate the efficacy and safety of placing two parallel catheters by Seldinger`s approach through the femoral artery for CT angiography (CTA) and CT during arterioportography (CTAP). We performed an analysis of 30 patients. Two introducers were successfully placed in all cases. Only one minor complication was observed, a localized inguinal hematoma. The CTA/CTAP procedures were successful in all patients except six who had anatomical variations of the hepatic arterial supply. Our methods proved to be useful and safe for patients with standard hepatic arterial supply. (author)

  3. Comprehensive vascular imaging using optical coherence tomography-based angiography and photoacoustic tomography

    Science.gov (United States)

    Zabihian, Behrooz; Chen, Zhe; Rank, Elisabet; Sinz, Christoph; Bonesi, Marco; Sattmann, Harald; Ensher, Jason; Minneman, Michael P.; Hoover, Erich; Weingast, Jessika; Ginner, Laurin; Leitgeb, Rainer; Kittler, Harald; Zhang, Edward; Beard, Paul; Drexler, Wolfgang; Liu, Mengyang

    2016-09-01

    Studies have proven the relationship between cutaneous vasculature abnormalities and dermatological disorders, but to image vasculature noninvasively in vivo, advanced optical imaging techniques are required. In this study, we imaged a palm of a healthy volunteer and three subjects with cutaneous abnormalities with photoacoustic tomography (PAT) and optical coherence tomography with angiography extension (OCTA). Capillaries in the papillary dermis that are too small to be discerned with PAT are visualized with OCTA. From our results, we speculate that the PA signal from the palm is mostly from hemoglobin in capillaries rather than melanin, knowing that melanin concentration in volar skin is significantly smaller than that in other areas of the skin. We present for the first time OCTA images of capillaries along with the PAT images of the deeper vessels, demonstrating the complementary effective imaging depth range and the visualization capabilities of PAT and OCTA for imaging human skin in vivo. The proposed imaging system in this study could significantly improve treatment monitoring of dermatological diseases associated with cutaneous vasculature abnormalities.

  4. Influence of the Accuracy of Angiography-Based Reconstructions on Velocity and Wall Shear Stress Computations in Coronary Bifurcations: A Phantom Study.

    Directory of Open Access Journals (Sweden)

    Jelle T C Schrauwen

    Full Text Available Wall shear stress (WSS plays a key role in the onset and progression of atherosclerosis in human coronary arteries. Especially sites with low and oscillating WSS near bifurcations have a higher propensity to develop atherosclerosis. WSS computations in coronary bifurcations can be performed in angiography-based 3D reconstructions. It is essential to evaluate how reconstruction errors influence WSS computations in mildly-diseased coronary bifurcations. In mildly-diseased lesions WSS could potentially provide more insight in plaque progression.Four Plexiglas phantom models of coronary bifurcations were imaged with bi-plane angiography. The lumens were segmented by two clinically experienced readers. Based on the segmentations 3D models were generated. This resulted in three models per phantom: one gold-standard from the phantom model itself, and one from each reader. Steady-state and transient simulations were performed with computational fluid dynamics to compute the WSS. A similarity index and a noninferiority test were used to compare the WSS in the phantoms and their reconstructions. The margin for this test was based on the resolution constraints of angiography.The reconstruction errors were similar to previously reported data; in seven out of eight reconstructions less than 0.10 mm. WSS in the regions proximal and far distal of the stenosis showed a good agreement. However, the low WSS areas directly distal of the stenosis showed some disagreement between the phantoms and the readers. This was due to small deviations in the reconstruction of the stenosis that caused differences in the resulting jet, and consequently the size and location of the low WSS area.This study showed that WSS can accurately be computed within angiography-based 3D reconstructions of coronary arteries with early stage atherosclerosis. Qualitatively, there was a good agreement between the phantoms and the readers. Quantitatively, the low WSS regions directly distal to

  5. A framework for organ dose estimation in x-ray angiography and interventional radiology based on dose-related data in DICOM structured reports

    Science.gov (United States)

    Omar, Artur; Bujila, Robert; Fransson, Annette; Andreo, Pedro; Poludniowski, Gavin

    2016-04-01

    Although interventional x-ray angiography (XA) procedures involve relatively high radiation doses that can lead to deterministic tissue reactions in addition to stochastic effects, convenient and accurate estimation of absorbed organ doses has traditionally been out of reach. This has mainly been due to the absence of practical means to access dose-related data that describe the physical context of the numerous exposures during an XA procedure. The present work provides a comprehensive and general framework for the determination of absorbed organ dose, based on non-proprietary access to dose-related data by utilizing widely available DICOM radiation dose structured reports. The framework comprises a straightforward calculation workflow to determine the incident kerma and reconstruction of the geometrical relation between the projected x-ray beam and the patient’s anatomy. The latter is difficult in practice, as the position of the patient on the table top is unknown. A novel patient-specific approach for reconstruction of the patient position on the table is presented. The proposed approach was evaluated for 150 patients by comparing the estimated position of the primary irradiated organs (the target organs) with their position in clinical DICOM images. The approach is shown to locate the target organ position with a mean (max) deviation of 1.3 (4.3), 1.8 (3.6) and 1.4 (2.9) cm for neurovascular, adult and paediatric cardiovascular procedures, respectively. To illustrate the utility of the framework for systematic and automated organ dose estimation in routine clinical practice, a prototype implementation of the framework with Monte Carlo simulations is included.

  6. Prospective ECG-triggered coronary CT angiography: clinical value of noise-based tube current reduction method with iterative reconstruction.

    Directory of Open Access Journals (Sweden)

    Junlin Shen

    Full Text Available OBJECTIVES: To evaluate the clinical value of noise-based tube current reduction method with iterative reconstruction for obtaining consistent image quality with dose optimization in prospective electrocardiogram (ECG-triggered coronary CT angiography (CCTA. MATERIALS AND METHODS: We performed a prospective randomized study evaluating 338 patients undergoing CCTA with prospective ECG-triggering. Patients were randomly assigned to fixed tube current with filtered back projection (Group 1, n = 113, noise-based tube current with filtered back projection (Group 2, n = 109 or with iterative reconstruction (Group 3, n = 116. Tube voltage was fixed at 120 kV. Qualitative image quality was rated on a 5-point scale (1 = impaired, to 5 = excellent, with 3-5 defined as diagnostic. Image noise and signal intensity were measured; signal-to-noise ratio was calculated; radiation dose parameters were recorded. Statistical analyses included one-way analysis of variance, chi-square test, Kruskal-Wallis test and multivariable linear regression. RESULTS: Image noise was maintained at the target value of 35HU with small interquartile range for Group 2 (35.00-35.03HU and Group 3 (34.99-35.02HU, while from 28.73 to 37.87HU for Group 1. All images in the three groups were acceptable for diagnosis. A relative 20% and 51% reduction in effective dose for Group 2 (2.9 mSv and Group 3 (1.8 mSv were achieved compared with Group 1 (3.7 mSv. After adjustment for scan characteristics, iterative reconstruction was associated with 26% reduction in effective dose. CONCLUSION: Noise-based tube current reduction method with iterative reconstruction maintains image noise precisely at the desired level and achieves consistent image quality. Meanwhile, effective dose can be reduced by more than 50%.

  7. Registration-based filtering: An acceptable tool for noise reduction in left ventricular dynamic rotational angiography images?

    Science.gov (United States)

    Wielandts, Jean-Yves; De Buck, Stijn; Ector, Joris; Nuyens, Dieter; Maes, Frederik; Heidbuchel, Hein

    2014-03-01

    VT ablations could benefit from Dynamic 3D (4D) left ventricle (LV) visualization as road-map for anatomy-guided procedures. We developed a registration-based method that combines information of several cardiac phases to filter out noise and artifacts in low-dose 3D Rotational Angiography (3DRA) images. This also enables generation of accurate multi-phase surface models by semi-automatic segmentation (SAS). The method uses B-spline non-rigid inter-phase registration (IPR) and subsequent averaging of the registered 3DRA images of 4 cardiac phases, acquired with a slow atrial pacing protocol, and was validated on data from 5 porcine experiments. IPR parameter settings were optimized against manual delineations of the LVs using a composed similarity score (Q), dependent on DICE-coefficient, RMSDistance, Hausdorff (HD) and the percentage of inter-surface distances ≤3mm and ≤4mm. The latter are clinically acceptable error cut-off values. Validation was performed after SAS for varying voxel intensity thresholds (ISO), by comparison between models with and without prior use of IPR. Distances to the manual delineations at optimal ISO were reduced to ≤3mm for 95.6±2.7% and to ≤4mm for 97.1±2.0% of model surfaces. Improved quality was proven by significant mean Q-increase irrespective of ISO (7.6% at optimal ISO (95%CI 4.6-10.5,pmodels proved feasible, with sufficient accuracy for clinical applications, opening the perspective of more accurate overlay and guidance during ablation in locations with high degrees of movement.

  8. Magnetic resonance angiography

    Science.gov (United States)

    ... in the wall of the blood vessel) Aortic coarctation Aortic dissection Stroke Carotid artery disease Atherosclerosis of ... 13, 2016. Read More Aortic angiography Aortic dissection Coarctation of the aorta Coronary heart disease Hardening of ...

  9. Angiography with a multifunctional line scanning ophthalmoscope

    Science.gov (United States)

    Hammer, Daniel X.; Ferguson, R. Daniel; Patel, Ankit H.; Vazquez, Vanessa; Husain, Deeba

    2012-02-01

    A multifunctional line scanning ophthalmoscope (mLSO) was designed, constructed, and tested on human subjects. The mLSO could sequentially acquire wide-field, confocal, near-infrared reflectance, fluorescein angiography (FA), and indocyanine green angiography (ICGA) retinal images. The system also included a retinal tracker (RT) and a photodynamic therapy laser treatment port. The mLSO was tested in a pilot clinical study on human subjects with and without retinal disease. The instrument exhibited robust retinal tracking and high-contrast line scanning imaging. The FA and ICGA angiograms showed a similar appearance of hyper- and hypo-pigmented disease features and a nearly equivalent resolution of fine capillaries compared to a commercial flood-illumination fundus imager. An mLSO-based platform will enable researchers and clinicians to image human and animal eyes with a variety of modalities and deliver therapeutic beams from a single automated interface. This approach has the potential to improve patient comfort and reduce imaging session times, allowing clinicians to better diagnose, plan, and conduct patient procedures with improved outcomes.

  10. Effect of Left Versus Right Radial Artery Approach for Coronary Angiography on Radiation Parameters in Patients With Predictors of Transradial Access Failure.

    Science.gov (United States)

    Shah, Binita; Burdowski, Joseph; Guo, Yu; Velez de Villa, Bryan; Huynh, Andrew; Farid, Meena; Maini, Mansi; Serrano-Gomez, Claudia; Staniloae, Cezar; Feit, Frederick; Attubato, Michael J; Slater, James; Coppola, John

    2016-08-15

    Left transradial approach (TRA) for coronary angiography is associated with lower radiation parameters than right TRA in an all-comers population. The aim of this study was to determine the effects of left versus right TRA on radiation parameters in patients with predictors of TRA failure. Patients with predictors of TRA failure (≥3 of 4 following criteria: age ≥70 years, female gender, height ≤64 inches, and hypertension) referred to TRA operators were randomized to either right (n = 50) or left (n = 50) TRA, whereas those referred to transfemoral approach (TFA) operators were enrolled in a prospective registry (n = 50). The primary end point was the radiation measure of dose-area product (DAP). In an intention-to-treat analysis, DAP (34.1 Gy·cm(2) [24.9 to 45.6] vs 41.9 Gy·cm(2) [27.3 to 58.0], p = 0.08), fluoroscopy time (3.7 minutes [2.4 to 6.3] vs 5.6 minutes [3.1 to 8.7], p = 0.07), and operator radiation exposure (516 μR [275 to 967] vs 730 μR [503 to 1,165], p = 0.06) were not significantly different between left and right TRA, but total dose (411 mGy [310 to 592] vs 537 mGy [368 to 780], p = 0.03) was significantly lower with left versus right TRA. Radiation parameters were lowest in the TFA cohort (DAP 24.5 Gy·cm(2) [15.7 to 33.2], p right TRA in this select population of patients with predictors of TRA failure. All measurements of radiation were lowest in the TFA group.

  11. Equilibrium-phase MR angiography: Comparison of unspecific extracellular and protein-binding gadolinium-based contrast media with respect to image quality.

    Science.gov (United States)

    Erb-Eigner, Katharina; Taupitz, Matthias; Asbach, Patrick

    2016-01-01

    The purpose of this study was to compare contrast and image quality of whole-body equilibrium-phase high-spatial-resolution MR angiography using a non-protein-binding unspecific extracellular gadolinium-based contrast medium with that of two contrast media with different protein-binding properties. 45 patients were examined using either 15 mL of gadobutrol (non-protein-binding, n = 15), 32 mL of gadobenate dimeglumine (weakly protein binding, n = 15) or 11 mL gadofosveset trisodium (protein binding, n = 15) followed by equilibrium-phase high-spatial-resolution MR-angiography of four consecutive anatomic regions. The time elapsed between the contrast injection and the beginning of the equilibrium-phase image acquisition in the respective region was measured and was up to 21 min. Signal intensity was measured in two vessels per region and in muscle tissue. Relative contrast (RC) values were calculated. Vessel contrast, artifacts and image quality were rated by two radiologists in consensus on a five-point scale. Compared with gadobutrol, gadofosveset trisodium revealed significantly higher RC values only when acquired later than 15 min after bolus injection. Otherwise, no significant differences between the three contrast media were found regarding vascular contrast and image quality. Equilibrium-phase high-spatial-resolution MR-angiography using a weakly protein-binding or even non-protein-binding contrast medium is equivalent to using a stronger protein-binding contrast medium when image acquisition is within the first 15 min after contrast injection, and allows depiction of the vasculature with high contrast and image quality. The protein-binding contrast medium was superior for imaging only later than 15 min after contrast medium injection.

  12. MR angiography with Vasovist

    Energy Technology Data Exchange (ETDEWEB)

    Goyen, Mathias [University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20251 Hamburg (Germany)], E-mail: goyen@uke.uni-hamburg.de

    2007-12-15

    Vasovist (Gadofosveset) is the first intravascular contrast agent approved for use with magnetic resonance angiography in the European Union. This blood pool contrast agent reversibly binds to albumin providing extended intravascular enhancement compared to existing extracellular magnetic resonance contrast agents. Prior to approval, Vasovist underwent extensive clinical and pre-clinical testing to evaluate the safety and efficacy of the drug. The clinical trials program included blinded, placebo-controlled dose ranging, efficacy in a variety of vascular beds (aorto-iliac, renal, pedal), examination of potential drug interaction with warfarin, and comparison with X-ray angiography. The clinical trials show that Vasovist-enhanced MR angiography is safe and well tolerated in patients with vascular disease, effective for the detection of vascular stenosis and aneurysms, significantly more accurate (both more sensitive and specific) than non-contrast MR angiography for the diagnosis of vascular stenoses, and similar to conventional angiography for the overall characterization of vascular disease, without the need for catheterization. This review article highlights the product characteristics of Vasovist, gives an overview of the clinical development program and discusses selected clinical applications.

  13. Incremental prognostic utility of coronary CT angiography for asymptomatic patients based upon extent and severity of coronary artery calcium: Results from the COronary CT Angiography EvaluatioN For Clinical Outcomes InteRnational Multicenter (CONFIRM) Study

    NARCIS (Netherlands)

    I. Cho (Iksung); H.-J. Chang (Hyuk-Jae); B.T. Hartaigh (Bríain ó); S. Shin (Sanghoon); J.M. Sung (Ji Min); F.Y. Lin (Fay); S. Achenbach (Stephan); R. Heo (Ran); D.S. Berman (Daniel); M.J. Budoff (Matthew J.); T.Q. Callister (Tracy); M. Al-Mallah (Mouaz); F. Cademartiri (Filippo); K. Chinnaiyan (Kavitha); B.J.W. Chow (Benjamin); A.M. Dunning (Allison M.); A. Delago (Augustin); T.C. Villines (Todd); M. Hadamitzky (Martin); J. Hausleiter (Jörg); J. Leipsic (Jonathon); L.J. Shaw (Leslee); P.A. Kaufmann (Philipp A.); R.C. Cury (Ricardo); G.M. Feuchtner (Gudrun); Y.-J. Kim (Yong-Jin); E. Maffei (Erica); G.L. Raff (Gilbert); G. Pontone (Gianluca); D. Andreini (Daniele); J.K. Min (James K.)

    2015-01-01

    textabstractAim Prior evidence observed no predictive utility of coronary CT angiography (CCTA) over the coronary artery calcium score (CACS) and the Framingham risk score (FRS), among asymptomatic individuals. Whether the prognostic value of CCTA differs for asymptomatic patients, when stratified b

  14. Image quality of low mA CT pulmonary angiography reconstructed with model based iterative reconstruction versus standard CT pulmonary angiography reconstructed with filtered back projection: an equivalency trial

    Energy Technology Data Exchange (ETDEWEB)

    Montet, Xavier; Hachulla, Anne-Lise; Neroladaki, Angeliki; Botsikas, Diomidis; Becker, Christoph D. [Geneva University Hospital, Division of Radiology, Geneva 4 (Switzerland); Lador, Frederic; Rochat, Thierry [Geneva University Hospital, Division of Pulmonary Medicine, Geneva 4 (Switzerland)

    2015-06-01

    To determine whether CT pulmonary angiography (CTPA) using low mA setting reconstructed with model-based iterative reconstruction (MBIR) is equivalent to routine CTPA reconstructed with filtered back projection (FBP). This prospective study was approved by the institutional review board and patients provided written informed consent. Eighty-two patients were examined with a low mA MBIR-CTPA (100 kV, 20 mA) and 82 patients with a standard FBP-CTPA (100 kV, 250 mA). Region of interests were drawn in nine pulmonary vessels; signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. A five-point scale was used to subjectively evaluate the image quality of FBP-CTPA and low mA MBIR-CTPA. Compared to routine FBP-CTPA, low mA MBIR-CTPA showed no differences in the attenuation measured in nine pulmonary vessels, higher SNR (56 ± 19 vs 43 ± 20, p < 0.0001) and higher CNR (50 ± 17 vs 38 ± 18, p < 0.0001) despite a dose reduction of 93 % (p < 0.0001). The subjective image quality of low mA MBIR-CTPA was quoted as diagnostic in 98 % of the cases for patient with body mass index less than 30 kg/m{sup 2}. Low mA MBIR-CTPA is equivalent to routine FBP-CTPA and allows a significant dose reduction while improving SNR and CNR in the pulmonary vessels, as compared with routine FBP-CTPA. (orig.)

  15. Coronary Computed Tomography Angiography (CTA)

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z Coronary Computed Tomography Angiography (CCTA) Coronary computed tomography angiography (CCTA) ... images. These images can be viewed on a computer monitor, printed on film or transferred to a ...

  16. Noninvasive coronary artery angiography using electron beam computed tomography

    Science.gov (United States)

    Rumberger, John A.; Rensing, Benno J.; Reed, Judd E.; Ritman, Erik L.; Sheedy, Patrick F., II

    1996-04-01

    Electron beam computed tomography (EBCT), also known as ultrafast-CT or cine-CT, uses a unique scanning architecture which allows for multiple high spatial resolution electrocardiographic triggered images of the beating heart. A recent study has demonstrated the feasibility of qualitative comparisons between EBCT derived 3D coronary angiograms and invasive angiography. Stenoses of the proximal portions of the left anterior descending and right coronary arteries were readily identified, but description of atherosclerotic narrowing in the left circumflex artery (and distal epicardial disease) was not possible with any degree of confidence. Although these preliminary studies support the notion that this approach has potential, the images overall were suboptimal for clinical application as an adjunct to invasive angiography. Furthermore, these studies did not examine different methods of EBCT scan acquisition, tomographic slice thicknesses, extent of scan overlap, or other segmentation, thresholding, and interpolation algorithms. Our laboratory has initiated investigation of these aspects and limitations of EBCT coronary angiography. Specific areas of research include defining effects of cardiac orientation; defining the effects of tomographic slice thickness and intensity (gradient) versus positional (shaped based) interpolation; and defining applicability of imaging each of the major epicardial coronary arteries for quantitative definition of vessel size, cross-sectional area, taper, and discrete vessel narrowing.

  17. MR angiography (MRA)

    Energy Technology Data Exchange (ETDEWEB)

    Hasuo, Kanehiro [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

    1995-12-01

    The primary goal of vascular imaging is the visualization of morphology and hemodynamics. Catheter angiography has been regarded as a gold standard for this purpose. However, MR angiography (MRA) is now increasingly being recognized as an important noninvasive technique for the depiction of vascular diseases and is partially superseding catheter angiography. The author evaluated the usefulness of MRA in the diagnosis of cerebral aneurysms and moyamoya disease. All aneurysms 5 mm or larger in diameter could be detected and most of those less than 5 mm in diameter were also detectable with using a combination of MIP images, target MIP images and source images. In moyamoya disease, the diagnosis could be made in all. For hemodynamic changes, flow directions in the circle of Willis could be visualized by phase-contrast MRA in a normal volunteer. In addition, MRA successfully showed the patency of surgical collaterals in cases of moyamoya disease. Despite some limitations compared with catheter angiography, MRA has a high sensitivity and specificity in the diagnosis of cerebrovascular abnormalities. Furthermore, screening of cerebral aneurysms or cerebrovascular occlusive diseases seems to be a new, and important indication for MRA. (author).

  18. Evaluation of Patients’ Exposure during Angiography and Angioplasty Procedures in the Angiography Department of Shahid Madani Hospital in Tabriz

    Directory of Open Access Journals (Sweden)

    Asghar Mesbahi

    2009-03-01

    Full Text Available Introduction: Coronary angiography and angioplasty procedures lead to significant radiation exposure of patients. In the current study, the average radiation dose to patients during angiography in the Angiography Department of Shahid-Madani Hospital was determined. Materials and Methods: An image intensifier based angiography unit (Philips BH 3000 was used for angiography procedures. The accuracy of the internal dosimeter was verified. Dose-area products (DAP of patients (236 cases during fluoroscopy and cine acquisition were recorded. Analyzing the data, the average radiation doses to patients for angiography and angioplasty and also for fluoroscopy and cine acquisition were determined. Additionally, the average fluoroscopy time for all patients was estimated. Results: The average DAPs of 23.7 and 91.5 Gycm2 were estimated for angiography and angioplasty respectively. Patient doses including fluoroscopy, cine acquisition and the total dose for angiography were 2, 7.7 and 3.8 times lower than angioplasty procedures respectively. Average fluoroscopy time was 1.9 times lower for angiography compared to angioplasty. Discussion and Conclusion: Fluoroscopy time and patient dose during fluoroscopy were in good agreement with other studies. However, the dose to patients during angioplasty was higher compared to other reports. To reduce patient dose in angioplasty procedures, the use of the lowest available frame rate, smallest field size and retraining of operators and technologists are recommended.

  19. Optical Coherence Tomography Angiography in Fovea Plana.

    Science.gov (United States)

    Dolz-Marco, Rosa; Phasukkijwatana, Nopasak; Sarraf, David; Freund, K Bailey

    2016-07-01

    Fovea plana is characterized by the anatomical absence of the foveal pit in eyes with normal visual function. The authors have analyzed three cases of idiopathic fovea plana with optical coherence tomography angiography (OCTA). As previously reported, the authors found the absence of a foveal avascular zone in all cases with OCTA; however, a preserved fusion of both the superficial and the deep capillary plexuses was found around the foveal center. This novel observation cannot be detected with conventional dye-based angiography, in which the deep capillary plexus is not visualized. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:670-673.].

  20. Three-dimensional reconstruction of coronary stents in vivo based on motion compensated X-ray angiography

    Science.gov (United States)

    Schäfer, Dirk; Movassaghi, Babak; Grass, Michael; Schoonenberg, Gert; Florent, Raoul; Wink, Onno; Klein, Andrew J. P.; Chen, James Y.; Garcia, Joel; Messenger, John C.; Carroll, John D.

    2007-03-01

    The complete expansion of the stent during a percutaneous transluminal coronary angioplasty (PTCA) procedure is essential for treatment of a stenotic segment of a coronary artery. Inadequate expansion of the stent is a major predisposing factor to in-stent restenosis and acute thrombosis. Stents are positioned and deployed by fluoroscopic guidance. Although the current generation of stents are made of materials with some degree of radio-opacity to detect their location after deployment, proper stent expansion is hard to asses. In this work, we introduce a new method for the three-dimensional (3D) reconstruction of the coronary stents in-vivo utilizing two-dimensional projection images acquired during rotational angiography (RA). The acquisition protocol consist of a propeller rotation of the X-ray C-arm system of 180°, which ensures sufficient angular coverage for volume reconstruction. The angiographic projections were acquired at 30 frames per second resulting in 180 projections during a 7 second rotational run. The motion of the stent is estimated from the automatically tracked 2D coordinates of the markers on the balloon catheter. This information is used within a motion-compensated reconstruction algorithm. Therefore, projections from different cardiac phases and motion states can be used, resulting in improved signal-to-noise ratio of the stent. Results of 3D reconstructed coronary stents in vivo, with high spatial resolution are presented. The proposed method allows for a comprehensive and unique quantitative 3D assessment of stent expansion that rivals current X-ray and intravascular ultrasound techniques.

  1. Incremental prognostic utility of coronary CT angiography for asymptomatic patients based upon extent and severity of coronary artery calcium: results from the COronary CT Angiography EvaluatioN For Clinical Outcomes InteRnational Multicenter (CONFIRM) Study

    Science.gov (United States)

    Cho, Iksung; Chang, Hyuk-Jae; Ó Hartaigh, Bríain; Shin, Sanghoon; Sung, Ji Min; Lin, Fay Y.; Achenbach, Stephan; Heo, Ran; Berman, Daniel S.; Budoff, Matthew J.; Callister, Tracy Q.; Al-Mallah, Mouaz H.; Cademartiri, Filippo; Chinnaiyan, Kavitha; Chow, Benjamin J.W.; Dunning, Allison M.; DeLago, Augustin; Villines, Todd C.; Hadamitzky, Martin; Hausleiter, Joerg; Leipsic, Jonathon; Shaw, Leslee J.; Kaufmann, Philipp A.; Cury, Ricardo C.; Feuchtner, Gudrun; Kim, Yong-Jin; Maffei, Erica; Raff, Gilbert; Pontone, Gianluca; Andreini, Daniele; Min, James K.

    2015-01-01

    Aim Prior evidence observed no predictive utility of coronary CT angiography (CCTA) over the coronary artery calcium score (CACS) and the Framingham risk score (FRS), among asymptomatic individuals. Whether the prognostic value of CCTA differs for asymptomatic patients, when stratified by CACS severity, remains unknown. Methods and results From a 12-centre, 6-country observational registry, 3217 asymptomatic individuals without known coronary artery disease (CAD) underwent CACS and CCTA. Individuals were categorized by CACS as: 0–10, 11–100, 101–400, 401–1000, >1000. For CCTA analysis, the number of obstructive vessels—as defined by the per-patient presence of a ≥50% luminal stenosis—was used to grade the extent and severity of CAD. The incremental prognostic value of CCTA over and above FRS was measured by the likelihood ratio (LR) χ2, C-statistic, and continuous net reclassification improvement (NRI) for prediction, discrimination, and reclassification of all-cause mortality and non-fatal myocardial infarction. During a median follow-up of 24 months (25th–75th percentile, 17–30 months), there were 58 composite end-points. The incremental value of CCTA over FRS was demonstrated in individuals with CACS >100 (LRχ2, 25.34; increment in C-statistic, 0.24; NRI, 0.62, all P 0.05). For subgroups with CACS >100, the utility of CCTA for predicting the study end-point was evident among individuals whose CACS ranged from 101 to 400; the observed predictive benefit attenuated with increasing CACS. Conclusion Coronary CT angiography provides incremental prognostic utility for prediction of mortality and non-fatal myocardial infarction for asymptomatic individuals with moderately high CACS, but not for lower or higher CACS. PMID:25205531

  2. Use of 3D-computed tomography angiography for planning the surgical removal of pineal region meningiomas using Poppen's approach: a report of ten cases and a literature review

    Directory of Open Access Journals (Sweden)

    Li Ye

    2011-06-01

    Full Text Available Abstract Background There are several treatment approaches for pineal region meningiomas, such as Poppen's approach, Krause's approach and combinations of the two approaches. We present our experience with the use of 3D-computed tomography angiography for planning the surgical removal of pineal region meningiomas using a suboccipital transtentorial approach (Poppen's approach and evaluate the role of Poppen's approach. Methods During the period from January 2005 to June 2010, ten patients presented to us with pineal region meningioma. MRI was routinely used to define the tumor size, position, and its relevant complications while 3D-CTA was applied to define the blood supply of the tumor and the venous complex (VC shift before operations. Most of the meningiomas had developed at both sides of the tentorial plane and extended laterally with typical characteristics of a pineal region tumor. Results All tumors were completely removed surgically without any injury to the VC. Postoperative intracranial infection occurred in one case who recovered after antibiotics were given. Postoperative intraventricular hemorrhage and pneumocephalus were found in one case, but fully recovered after conservative treatment. In the nine cases of concurrent hydrocephalus, this was gradually relieved in eight patients and the single case that became aggravated was successfully treated with ventriculoperitoneal shunt. Moreover, the follow-up MRI examinations did not indicate any recurrence of the meningiomas. Conclusion We found that the use of Poppen's approach is strongly supported for the successful removal of pineal region meningiomas without serious complications.

  3. Novel methodology for 3D reconstruction of carotid arteries and plaque characterization based upon magnetic resonance imaging carotid angiography data.

    Science.gov (United States)

    Sakellarios, Antonis I; Stefanou, Kostas; Siogkas, Panagiotis; Tsakanikas, Vasilis D; Bourantas, Christos V; Athanasiou, Lambros; Exarchos, Themis P; Fotiou, Evangelos; Naka, Katerina K; Papafaklis, Michail I; Patterson, Andrew J; Young, Victoria E L; Gillard, Jonathan H; Michalis, Lampros K; Fotiadis, Dimitrios I

    2012-10-01

    In this study, we present a novel methodology that allows reliable segmentation of the magnetic resonance images (MRIs) for accurate fully automated three-dimensional (3D) reconstruction of the carotid arteries and semiautomated characterization of plaque type. Our approach uses active contours to detect the luminal borders in the time-of-flight images and the outer vessel wall borders in the T(1)-weighted images. The methodology incorporates the connecting components theory for the automated identification of the bifurcation region and a knowledge-based algorithm for the accurate characterization of the plaque components. The proposed segmentation method was validated in randomly selected MRI frames analyzed offline by two expert observers. The interobserver variability of the method for the lumen and outer vessel wall was -1.60%±6.70% and 0.56%±6.28%, respectively, while the Williams Index for all metrics was close to unity. The methodology implemented to identify the composition of the plaque was also validated in 591 images acquired from 24 patients. The obtained Cohen's k was 0.68 (0.60-0.76) for lipid plaques, while the time needed to process an MRI sequence for 3D reconstruction was only 30 s. The obtained results indicate that the proposed methodology allows reliable and automated detection of the luminal and vessel wall borders and fast and accurate characterization of plaque type in carotid MRI sequences. These features render the currently presented methodology a useful tool in the clinical and research arena.

  4. Coronary CT angiography and MR angiography of Kawasaki disease

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo [University of Ulsan College of Medicine, Department of Radiology, Asan Medical Center, 388-1 Poongnap-2dong, Songpa-gu, Seoul (Korea); Park, In-Sook; Ko, Jae Kon; Kim, Young Hwee [University of Ulsan College of Medicine, Department of Paediatric Cardiology, Asan Medical Center, Seoul (Korea)

    2006-07-15

    Although the incidence of coronary artery aneurysms has diminished in patients with Kawasaki disease, coronary artery involvement is still regarded as a major complication of the disease, significantly affecting morbidity and mortality. Recent technical advances in coronary CT angiography (CTA) and MR angiography (MRA) have led to the possibility of using these two imaging methods as minimally invasive alternatives to the more invasive diagnostic catheter angiography in evaluating coronary artery abnormalities, such as aneurysm, stenosis, and occlusion. In this article, we describe imaging techniques and findings of coronary CTA and MRA in Kawasaki disease. (orig.)

  5. CT angiography after carotid artery stenting: assessment of the utility of adaptive statistical iterative reconstruction and model-based iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Kuya, Keita; Shinohara, Yuki; Fujii, Shinya; Ogawa, Toshihide [Tottori University, Division of Radiology, Department of Pathophysiological Therapeutic Science, Faculty of Medicine, Yonago (Japan); Sakamoto, Makoto; Watanabe, Takashi [Tottori University, Division of Neurosurgery, Department of Brain and Neurosciences, Faculty of Medicine, Yonago (Japan); Iwata, Naoki; Kishimoto, Junichi [Tottori University, Division of Clinical Radiology Faculty of Medicine, Yonago (Japan); Kaminou, Toshio [Osaka Minami Medical Center, Department of Radiology, Osaka (Japan)

    2014-11-15

    Follow-up CT angiography (CTA) is routinely performed for post-procedure management after carotid artery stenting (CAS). However, the stent lumen tends to be underestimated because of stent artifacts on CTA reconstructed with the filtered back projection (FBP) technique. We assessed the utility of new iterative reconstruction techniques, such as adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR), for CTA after CAS in comparison with FBP. In a phantom study, we evaluated the differences among the three reconstruction techniques with regard to the relationship between the stent luminal diameter and the degree of underestimation of stent luminal diameter. In a clinical study, 34 patients who underwent follow-up CTA after CAS were included. We compared the stent luminal diameters among FBP, ASIR, and MBIR, and performed visual assessment of low attenuation area (LAA) in the stent lumen using a three-point scale. In the phantom study, stent luminal diameter was increasingly underestimated as luminal diameter became smaller in all CTA images. Stent luminal diameter was larger with MBIR than with the other reconstruction techniques. Similarly, in the clinical study, stent luminal diameter was larger with MBIR than with the other reconstruction techniques. LAA detectability scores of MBIR were greater than or equal to those of FBP and ASIR in all cases. MBIR improved the accuracy of assessment of stent luminal diameter and LAA detectability in the stent lumen when compared with FBP and ASIR. We conclude that MBIR is a useful reconstruction technique for CTA after CAS. (orig.)

  6. CT angiography - abdomen and pelvis

    Science.gov (United States)

    Computed tomography angiography - abdomen and pelvis; CTA - abdomen and pelvis; Renal artery - CTA; Aortic - CTA; Mesenteric CTA ... belly or pelvis Masses and tumors in the abdomen or pelvis, including cancer, when needed to help ...

  7. The role of MR angiography in neuroradiology

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Mutsumasa (Kumamoto Univ. (Japan). School of Medicine)

    1991-09-01

    Ninety-nine patients suspected of having intracranial and cervical lesions were evaluated with magnetic resonance (MR) angiography. The time of flight technique was used with 3D FIPS, including flip angle of 15-25 degrees, TR 40 msec/TE 7 msec and acquisition matrix of 256 x 256 x 32-64 with slice thickness of 5 to 8 cm. The scan time was 5 minutes and 28 seconds for images of 32 partitions and 10 minutes and 56 seconds for images of 64 partitions. MR angiography was useful for diagnosing steno-occlusive disease, arteriovenous malformation, aneurysm, moyamoya disease, brain tumor, and facial or trigeminal compression. The method has disadvantages, including signal loss due to turbulent and complex flow, lower spatial resolution, and poor delineation of the periphery and slow blood flow. Useful information was obtained in 50 patients (53.2%), when used with spin echo methods. With the technical progress of MR angiography, it will become a promising noninvasive approach to neuroradiological diagnosis, providing the useful information on intracranial and cervical lesions. (N.K.).

  8. The comparative study on diagnostic validity of cerebral aneurysm by computed tomography angiography versus digital subtraction angiography after subarachnoid hemorrhage

    Directory of Open Access Journals (Sweden)

    Masih Saboori

    2011-01-01

    Full Text Available Background: In order to declare the preoperative diagnostic value of brain aneurysms, two radiological modalities, computed tomographic angiography and digital subtraction angiography were compared. Methods: In this descriptive analytic study, diagnostic value of computed tomographic angiography (CTA was com-pared with digital subtraction angiography (DSA. Sensitivity, specificity, positive and negative predictive values were calculated and compared between the two modalities. All data were analyzed with SPSS software, version 16. Results: Mean age of patients was 49.5 ± 9.13 years. 57.9 % of subjects were female. CTA showed 89% sensitivity and 100% specificity whereas DSA demonstrated 74% sensitivity and 100% specificity. Positive predictive value of both methods was 100%, but negative predictive value of CTA and DSA was 85% and 69%, respectively. Conclusions: Based on our data, CTA is a valuable diagnostic modality for detection of brain aneurysm and su-barachnoid hemorrhage.

  9. Advanced image-based virtual monoenergetic dual-energy CT angiography of the abdomen: optimization of kiloelectron volt settings to improve image contrast

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, Moritz H.; Scholtz, Jan-Erik; Huesers, Kristina; Beeres, Martin; Bucher, Andreas M.; Kaup, Moritz; Martin, Simon S.; Fischer, Sebastian; Bodelle, Boris; Bauer, Ralf W.; Lehnert, Thomas; Vogl, Thomas J.; Wichmann, Julian L. [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany)

    2016-06-15

    To compare quantitative image quality parameters in abdominal dual-energy computed tomography angiography (DE-CTA) using an advanced image-based (Mono+) reconstruction algorithm for virtual monoenergetic imaging and standard DE-CTA. Fifty-five patients (36 men; mean age, 64.2 ± 12.7 years) who underwent abdominal DE-CTA were retrospectively included. Mono + images were reconstructed at 40, 50, 60, 70, 80, 90 and 100 keV levels and as standard linearly blended M{sub 0}.6 images (60 % 100 kV, 40 % 140 kV). The contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) of the common hepatic (CHA), splenic (SA), superior mesenteric (SMA) and left renal arteries (LRA) were objectively measured. Mono+ DE-CTA series showed a statistically superior CNR for 40, 50, 60, 70 and 80 keV (P < 0.031) compared to M{sub 0}.6 images for all investigated arteries except SMA at 80 keV (P = 0.08). CNR at 40 keV revealed a mean relative increase of 287.7 % compared to linearly blended images among all assessed arteries (P < 0.001). SNR of Mono+ images was consistently significantly higher at 40, 50, 60 and 70 keV compared to M{sub 0}.6 for CHA and SA (P < 0.009). Compared to linearly blended images, Mono+ reconstructions at low keV levels of abdominal DE-CTA datasets significantly improve quantitative image quality. (orig.)

  10. CT-angiography-based evaluation of the aortic annulus for prosthesis sizing in transcatheter aortic valve implantation (TAVI-predictive value and optimal thresholds for major anatomic parameters.

    Directory of Open Access Journals (Sweden)

    Florian Schwarz

    Full Text Available BACKGROUND/OBJECTIVES: To evaluate the predictive value of CT-derived measurements of the aortic annulus for prosthesis sizing in transcatheter aortic valve implantation (TAVI and to calculate optimal cutoff values for the selection of various prosthesis sizes. METHODS: The local IRB waived approval for this single-center retrospective analysis. Of 441 consecutive TAVI-patients, 90 were excluded (death within 30 days: 13; more than mild aortic regurgitation: 10; other reasons: 67. In the remaining 351 patients, the CoreValve (Medtronic and the Edwards Sapien XT valve (Edwards Lifesciences were implanted in 235 and 116 patients. Optimal prosthesis size was determined during TAVI by inflation of a balloon catheter at the aortic annulus. All patients had undergone CT-angiography of the heart or body trunk prior to TAVI. Using these datasets, the diameter of the long and short axis as well as the circumference and the area of the aortic annulus were measured. Multi-Class Receiver-Operator-Curve analyses were used to determine the predictive value of all variables and to define optimal cutoff-values. RESULTS: Differences between patients who underwent implantation of the small, medium or large prosthesis were significant for all except the large vs. medium CoreValve (all p's<0.05. Furthermore, mean diameter, annulus area and circumference had equally high predictive value for prosthesis size for both manufacturers (multi-class AUC's: 0.80, 0.88, 0.91, 0.88, 0.88, 0.89. Using the calculated optimal cutoff-values, prosthesis size is predicted correctly in 85% of cases. CONCLUSION: CT-based aortic root measurements permit excellent prediction of the prosthesis size considered optimal during TAVI.

  11. Angiography-based prediction of outcome after coronary artery bypass surgery versus changes in myocardial perfusion scintigraphy

    DEFF Research Database (Denmark)

    Eckardt, Rozy; Kjeldsen, Bo Juel; Haghfelt, Torben;

    2011-01-01

    The present study compared the clinical prediction of the effect of coronary artery bypass grafting (CABG) on coronary blood flow and left ventricular ejection fraction (LVEF) with changes in gated myocardial perfusion scintigraphy. A prospective group of 92 patients underwent myocardial perfusion...... predicted and observed regional changes in coronary blood flow and perfusion defects were poor. LVEF increased (by over five ejection fraction units) in almost half of the patients, but with no correlation between the predicted and the observed changes. Based on clinical and angiographic findings...... scintigraphy before and 6 months after CABG, the results being kept secret from the surgeon. Based on clinical and angiographic findings, the surgeons filled in a questionnaire indicating the predicted changes in coronary blood flow in each of the three coronary artery territories and in the LVEF. Symptomatic...

  12. Contrast-enhanced MR angiography in patients after kidney transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Huber, A.; Heuck, A.; Scheidler, J.; Holzknecht, N.; Baur, A.; Reiser, M. [Klinikum Grosshadern, Muenchen (Germany). Radiologische Klinik und Poliklinik; Stangl, M.; Theodorakis, J.; Illner, W.-D.; Land, W. [Dept. of Transplant Surgery, Klinikum Grosshadern, Muenchen (Germany)

    2001-12-01

    The aim of this study was to investigate the value of a contrast-enhanced 3D MR angiography in detecting postoperative vascular complications after kidney transplantation in comparison with digital subtraction angiography (DSA). Forty-one patients who underwent a kidney transplantation were examined with MR angiography and DSA. Contrast-enhanced MR angiography was performed as a dynamic measurement with one precontrast and three postcontrast measurements. Maximum intensity projection reconstructions were performed for all postcontrast data sets after DSA. The results were evaluated by two independent observers who were unaware of the DSA results. Twenty-three hemodynamically significant arterial stenoses were identified with DSA in the iliac arteries (n=7), the renal allograft arteries (n=12), and in their first branches (n=4). For a patient-based analysis the sensitivity and specificity, respectively, for observer 1 were 100 and 97%, and for observer 2, 100 and 93%. Respective data were 100 and 100% after a consensus evaluation by two observers. Complications involving the renal veins were detected in 2 cases and perfusion defects of the kidney parenchyma were detected in 4 cases. Contrast-enhanced MR angiography is a reliable method in identifying postoperative arterial stenoses after kidney transplantation. In addition, dynamic MR angiography can be helpful in detecting venous complications and perfusion defects in kidney allografts. (orig.)

  13. Form-based Approaches vs. Task-Based Approaches

    Directory of Open Access Journals (Sweden)

    Zahra Talebi

    2015-07-01

    Full Text Available This study aimed at investigating whether task-based approaches bear any superiority to that of more traditional ones evident in presentation-practice- and production phase .to fulfill the purpose of the study, the participants within the age range of 11-19, took part in the study. Following a pretest, treatment, and a posttest, the obtained data was analyzed using analysis of covariance (ANCOVA to examine the effects of the variables. The results of the analysis showed that participants in the PPP group did significantly better in the grammar recognition of the posttest than that of the task group. However, their counterparts in the task group gained better scores in the writing section of the test .this research study provided evidence in support of task proponents' claim in the merit of task-based activity in raising learners' implicit knowledge claiming to play the primary role in spontaneous speech.Keywords: Task-based language teaching, PPP model, focus on form, focus on meaning

  14. Magnetic resonance angiography: technical aspects of a noninvasive method for vascular study; Angiografia por ressonancia magnetica: aspectos tecnicos de um metodo de estudo vascular nao-invasivo

    Energy Technology Data Exchange (ETDEWEB)

    Caldana, Rogerio Pedreschi; Bezerra, Alexandre Sergio de Araujo; D' Ippolito, Giuseppe [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. de Diagnostico por Imagem]. E-mail: rogercal@uol.com.br; Soares, Adriano Fleury de Faria [Complexo Hospitalar Sao Luiz, Sao Paulo, SP (Brazil)

    2004-02-01

    Early magnetic resonance angiography techniques used flow-sensitive sequences to obtain contrast of the vascular structures. Three techniques are based on this approach: phase-contrast, time-of-flight and black blood techniques. However, these acquisition methods are time-consuming and more susceptible to movement artifacts, flow-related artifacts and signal loss due to stenotic lesions. They also present low sensitivity for slow flow detection. The use of paramagnetic contrast medium in magnetic resonance angiography studies provides a simple and quick way of obtaining vascular enhancement. Image contrast is based on vascular enhancement in opposition to background suppression. Important factors for the technical improvement of gadolinium-enhanced magnetic resonance angiography is a useful diagnostic tool for investigation of anatomical anomalies, stenotic and occlusive disease, and surgical complications, particularly in patients with organ transplants. Gadolinium-enhanced magnetic resonance angiography is a useful diagnostic tool for investigation of anatomical anomalies, stenotic and occlusive disease, and surgical complications, particularly in patients with organ transplants. Gadolinium-enhanced magnetic resonance angiography has the advantage of a noninvasive method since it does not require ionizing radiation or an iodine contrast medium and allows the evaluation of parenchymatous structures for additional diagnostic information. (author)

  15. Ontology Partitioning: Clustering Based Approach

    Directory of Open Access Journals (Sweden)

    Soraya Setti Ahmed

    2015-05-01

    Full Text Available The semantic web goal is to share and integrate data across different domains and organizations. The knowledge representations of semantic data are made possible by ontology. As the usage of semantic web increases, construction of the semantic web ontologies is also increased. Moreover, due to the monolithic nature of the ontology various semantic web operations like query answering, data sharing, data matching, data reuse and data integration become more complicated as the size of ontology increases. Partitioning the ontology is the key solution to handle this scalability issue. In this work, we propose a revision and an enhancement of K-means clustering algorithm based on a new semantic similarity measure for partitioning given ontology into high quality modules. The results show that our approach produces meaningful clusters than the traditional algorithm of K-means.

  16. Three-dimensional computed tomography angiography for the investigation of superficial temporal artery pseudoaneurysms--two case reports--.

    Science.gov (United States)

    Higashino, Takuya; Kawashima, Masatou; Mannoji, Hiromichi

    2005-03-01

    An 89-year-old man and a 60-year-old man presented with superficial temporal artery (STA) pseudoaneurysms which developed secondary to trauma. Conventional cerebral angiography and three-dimensional computed tomography (3D CT) angiography clearly demonstrated the STA pseudoaneurysms. The patients underwent surgical excision of the aneurysms based on the conventional cerebral angiography findings in one patient and 3D CT angiography findings in other patient. 3D CT angiography is an excellent noninvasive diagnostic method for detecting extracranial aneurysms such as STA pseudoaneurysm, especially the relationship between the aneurysm and surrounding structures, including the calvarium.

  17. Materiality in a Practice-Based Approach

    Science.gov (United States)

    Svabo, Connie

    2009-01-01

    Purpose: The paper aims to provide an overview of the vocabulary for materiality which is used by practice-based approaches to organizational knowing. Design/methodology/approach: The overview is theoretically generated and is based on the anthology Knowing in Organizations: A Practice-based Approach edited by Nicolini, Gherardi and Yanow. The…

  18. Image quality of ultra-low radiation exposure coronary CT angiography with an effective dose <0.1 mSv using high-pitch spiral acquisition and raw data-based iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Schuhbaeck, Annika; Achenbach, Stephan; Hecker, Franziska; Rixe, Johannes [University of Giessen, Department of Cardiology, Giessen (Germany); Layritz, Christian; Eisentopf, Jasmin; Pflederer, Tobias; Gauss, Soeren; Kalender, Willi; Daniel, Werner G.; Lell, Michael; Ropers, Dieter [University of Erlangen, Departments of Cardiology and Radiology, Erlangen (Germany)

    2013-03-15

    We evaluated the potential of prospectively ECG-triggered high-pitch spiral acquisition with low tube voltage and current in combination with iterative reconstruction to achieve coronary CT angiography with sufficient image quality at an effective dose below 0.1 mSv. Contrast-enhanced coronary dual source CT angiography (2 x 128 x 0.6 mm, 80 kV, 50 mAs) in prospectively ECG-triggered high-pitch spiral acquisition mode was performed in 21 consecutive individuals (body weight <100 kg, heart rate {<=}60/min). Images were reconstructed with raw data-based filtered back projection (FBP) and iterative reconstruction (IR). Image quality was assessed on a 4-point scale (1 = no artefacts, 4 = unevaluable). Mean effective dose was 0.06 {+-} 0.01 mSv. Image noise was significantly reduced in IR (128.9 {+-} 46.6 vs. 158.2 {+-} 44.7 HU). The mean image quality score was lower for IR (1.9 {+-} 1.1 vs. 2.2 {+-} 1.0, P < 0.0001). Of 292 coronary segments, 55 in FBP and 40 in IR (P = 0.12) were graded ''unevaluable''. In patients with a body weight {<=}75 kg, both in FBP and in IR, the rates of fully evaluable segments were significantly higher in comparison to patients >75 kg. Coronary CT angiography with an estimated effective dose <0.1 mSv may provide sufficient image quality in selected patients through the combination of high-pitch spiral acquisition and raw data-based iterative reconstruction. (orig.)

  19. Acute gastrointestinal bleeding: CT angiography with multi-planar reformatting.

    Science.gov (United States)

    Steiner, Kate; Gollub, Frank; Stuart, Sam; Papadopoulou, Anthie; Woodward, Nick

    2011-04-01

    Acute gastrointestinal bleeding is a common medical emergency, which carries a significant mortality. CT Angiography is an important non-invasive diagnostic tool, which can be used to plan subsequent endovascular or surgical management. The cases presented demonstrate that a meticulous and systematic approach to image interpretation is necessary, in particular, to detect focal sites of contrast extravasation and small pseudoaneurysms.

  20. The importance of peripheral angiography in elderly patients undergoing coronary angiography

    Institute of Scientific and Technical Information of China (English)

    Gianluca Rigatelli; Giorgio Rigatelli

    2005-01-01

    Objectives Early and accurate diagnosis of peripheral atherosclerosis is of paramount importance for global managerment of patients with known coronary artery disease (CAD), especially in the elderly. We sought to evaluate the prevalence and clinical relevance of significant abdominal vessel stenosis or aneurysm (AVA) in patients undergoing coronary angiography. Methods Medical records of consecutive > 75-year old patients who underwent coronary angiography at two public institutions over a 12-month period were evaluated. Angiographic results of patients who underwent coincident diagnostic abdominal aorta angiography to evaluate abdominal vessels on the basis of clinical and angiographic criteria were analyzed. Results During the study period, AVA was found in 90 (35.7% ) of 252 consecutive patients (185 males, mean age 79±5.8 years), renal artery stenosis in 13.1% of cases (33 patients), aortoiliac artery disease in 13.7 % (35 patients), and aortic aneurismal disease in 8.9% (22 patients). Logistic regression analyses revealed > 3-vessel CAD (odds ratio [OR] :9.917, P = 0.002), and > 3 risk factors (OR: 2.8, P =0. 048) as independent predictors of AVA. Conclusions Aged patients with multivessel CAD frequently have a high risk profile and multiple vascular atherosclerotic distributions, suggesting the usefulness of a mere global and comprehensive cardiovascular approach in aged patients.

  1. Hyperpolarized 13C MR angiography

    DEFF Research Database (Denmark)

    Lipsø, Hans Kasper Wigh; Magnusson, Peter; Ardenkjær-Larsen, Jan Henrik

    2016-01-01

    Magnetic resonance angiography (MRA) is a non-invasive technology that can be used for diagnosis and monitoring of cardiovascular disease; the number one cause of mortality worldwide. Hyperpolarized imaging agents provide signal enhancement of more than 10, 000 times, which implies large reduction...

  2. Assessment of anemia during CT pulmonary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Caroline, E-mail: cjung@uke.de [Department of Diagnostic and Interventional Radiology, University Hospital Eppendorf, Martinistrasse 52, 20246 Hamburg (Germany); Groth, Michael; Bley, Thorsten A.; Henes, Frank O. [Department of Diagnostic and Interventional Radiology, University Hospital Eppendorf, Martinistrasse 52, 20246 Hamburg (Germany); Treszl, András [Department of Medical Biometry and Epidemiology, University Hospital Eppendorf, Martinistrasse 52, 20246 Hamburg (Germany); Adam, Gerhard; Bannas, Peter [Department of Diagnostic and Interventional Radiology, University Hospital Eppendorf, Martinistrasse 52, 20246 Hamburg (Germany)

    2012-12-15

    Objectives: Anemia is associated with increased mortality in patients with acute symptomatic pulmonary embolism (PE). The purpose of this study was to evaluate the feasibility of Hounsfield unit (HU) measurements on the single unenhanced trigger slice of pulmonary CT angiography scans for diagnosis of anemia. Material and Methods: 150 consecutive patients (median age 64 ± 16 years) with suspected PE underwent pulmonary CT angiography. Two radiologists, blinded to laboratory results, performed HU measurements in the single unenhanced trigger scan independently by region-based analysis (ROI). HU values from ascending and descending aorta and the calculated mean of both were correlated with serum hemoglobin levels. Inter- and intraobserver variability was determined for HU measurements, and ROC analysis was performed for diagnosis of anemia. Calculated linear models were used to assess formulas for estimation of hemoglobin levels from HU measurements. Results: HU measurements revealed high intra- and interrater reliability (ICC > 0.981 and ICC > 0.965, respectively). Calculated mean HU values showed a strong correlation with serum hemoglobin levels (r = 0.734), which allowed generation of different formulas for calculation of hemoglobin levels from HU measurements. ROC analyses confirmed a high sensitivity (80.4 for men; 91.3 for women) and specificity (84.0 for men; 84.9 for women) for diagnosing anemia. Conclusion: Diagnosis of anemia and quantification of hemoglobin levels upon a single unenhanced trigger scan of pulmonary CT angiography is feasible. We suggest disclosing the anemic state in the radiological report, independent of the presence of PE, since anemia carries increased risks of morbidity and mortality.

  3. A comparison of iopamidol and iohexol in cerebral angiography.

    Science.gov (United States)

    Pelz, D M; Fox, A J; Viñuela, F; Lylyk, P

    1988-01-01

    Iopamidol and iohexol, the new nonionic low-osmolality contrast agents, have both been shown to be safe, effective, and better tolerated than conventional ionic agents for cerebral angiography. In this randomized, double-blind study involving 40 patients, these two agents were compared for adverse effects, radiographic quality, and patient tolerance. No significant differences were observed in 220 injections. Because we found iopamidol and iohexol to be equally safe and effective for cerebral angiography, the choice of which contrast agent to use should be based on other considerations.

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

    Science.gov (United States)

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

    2010-01-01

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

  5. Model based feature fusion approach

    NARCIS (Netherlands)

    Schwering, P.B.W.

    2001-01-01

    In recent years different sensor data fusion approaches have been analyzed and evaluated in the field of mine detection. In various studies comparisons have been made between different techniques. Although claims can be made for advantages for using certain techniques, until now there has been no si

  6. Perfusion Angiography in Acute Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    Fabien Scalzo

    2016-01-01

    Full Text Available Visualization and quantification of blood flow are essential for the diagnosis and treatment evaluation of cerebrovascular diseases. For rapid imaging of the cerebrovasculature, digital subtraction angiography (DSA remains the gold standard as it offers high spatial resolution. This paper lays out a methodological framework, named perfusion angiography, for the quantitative analysis and visualization of blood flow parameters from DSA images. The parameters, including cerebral blood flow (CBF and cerebral blood volume (CBV, mean transit time (MTT, time-to-peak (TTP, and Tmax, are computed using a bolus tracking method based on the deconvolution of the time-density curve on a pixel-by-pixel basis. The method is tested on 66 acute ischemic stroke patients treated with thrombectomy and/or tissue plasminogen activator (tPA and also evaluated on an estimation task with known ground truth. This novel imaging tool provides unique insights into flow mechanisms that cannot be observed directly in DSA sequences and might be used to evaluate the impact of endovascular interventions more precisely.

  7. Evaluation of angiography performed by radiographers and nurses

    Energy Technology Data Exchange (ETDEWEB)

    Chalmers, N.; Conway, B.; Andrew, H.; Parkinson, A.; Butterfield, J.S.; Fawcitt, R. A

    2002-04-01

    AIM: To evaluate out-patient angiography performed by nurses and radiographers. MATERIALS AND METHODS: A protocol for out-patient angiography performed by nurses and radiographers was drawn up and approved by the Trust's Risk Management Committee. Following training, two experienced radiographers and one nurse undertook elective peripheral or renal angiography according to the protocol on 187 patients. Angiograms were performed using a 3F catheter introduced into the abdominal aorta from a femoral approach. Patients were discharged after 2 hours and contacted by telephone the following morning. RESULTS: No patient refused consent for the procedure. One hundred and seventy-two patients underwent successful catheterization without assistance from a radiologist. Radiologist assistance was required with femoral puncture or catheter/guidewire manipulation in 15 cases (8%). Images were considered diagnostic by the reporting radiologist in all but one case. This patient was recalled for further aortogram and pressure measurements. There was a single puncture site complication due to transient stenosis of the common femoral artery at the puncture site. This is thought to have been the result of subintimal injection of local anaesthetic, and it resolved spontaneously over 30 minutes. There were no delayed complications. CONCLUSION: Experienced nurses and radiographers can rapidly acquire the skills to perform diagnostic angiography safely and efficiently. Chalmers, N. et al. (2002)

  8. E-learn Computed Tomographic Angiography

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  9. Spiral CT angiography of renal arteries: comparison with angiography

    Energy Technology Data Exchange (ETDEWEB)

    Wittenberg, G.; Kenn, W.; Tschammler, A.; Sandstede, J.; Hahn, D. [Inst. fuer Roentgendiagnostik der Universitaet Wuerzburg (Germany)

    1999-04-01

    A prospective study was carried out to determine the accuracy of spiral CT angiography (CTA) in the detection of renal artery stenosis (RAS). Eighty-two patients with arterial hypertension underwent CTA and digital subtraction angiography (DSA) to exclude RAS. For CTA a contrast medium bolus of 100-150 ml (flow rate 3 ml/s) was injected. A 24 or 40 s CTA was started at the origin of the superior mesenteric artery after a delay time determined by test bolus injection (collimation = 2 mm, pitch = 1/1.5). For stenosis detection transverse images supported by maximum intensity projections (MIP) or multiplanar reconstruction projections were used. Of 197 renal arteries examined (including 33 accessory arteries), 34 RAS were visualized using DSA. With CTA, one hemodynamic RAS was missed and one additional hemodynamic RAS was found. Sensitivity/specificity was calculated to be 94 %/98 %. For hemodynamically relevant RAS (> 50 %) the sensitivity/specificity was 96 %/99 %. CTA additionally depicted five adrenal masses. The high accuracy rate of RAS detection thus allows the use of CTA as a screening method in patients with arterial hypertension to exclude a renovascular cause. (orig.) With 2 figs., 1 tab., 25 refs.

  10. Acquisition-related motion compensation for digital subtraction angiography.

    Science.gov (United States)

    Ionasec, Razvan Ioan; Heigl, Benno; Hornegger, Joachim

    2009-06-01

    Subtraction methods in angiography are generally applied in order to enhance the visualization of blood vessels by eliminating bones and surrounding tissues from X-ray images. The main limitation of these methods is the sensitivity to patient movement, which leads to artifacts and reduces the clinical value of the subtraction images. In this paper we present a novel method for rigid motion compensation with primary application to road mapping, frequently used in image-guided interventions. Using the general concept of image-based registration, we optimize the physical position and orientation of the C-arm X-ray device, thought of as the rigid 3D transformation accounting for the patient movement. The registration is carried out using a hierarchical optimization strategy and a similarity measure based on the variance of intensity differences, which has been shown to be most suitable for fluoroscopic images. Performance evaluation demonstrated the capabilities of the proposed approach to compensate for potential intra-operative patient motion, being more resilient to the fundamental problems of pure image-based registration.

  11. Balloon-Assisted Tracking to Overcome Radial Spasm during Transradial Coronary Angiography: A Case Report

    OpenAIRE

    Verouden, N. J. W.; Kiemeneij, F.

    2014-01-01

    Spasm of the radial artery is the most important cause of failure to perform coronary angiography via the transradial approach. Spasmolytic cocktail may prevent radial artery spasm but is relatively contraindicated in patients with aortic stenosis or diminished left ventricular function. In this case report we describe a recently published technique to overcome severe radial spasm during transradial coronary angiography in a patient with moderate aortic valve stenosis.

  12. Balloon-Assisted Tracking to Overcome Radial Spasm during Transradial Coronary Angiography: A Case Report.

    Science.gov (United States)

    Verouden, N J W; Kiemeneij, F

    2014-01-01

    Spasm of the radial artery is the most important cause of failure to perform coronary angiography via the transradial approach. Spasmolytic cocktail may prevent radial artery spasm but is relatively contraindicated in patients with aortic stenosis or diminished left ventricular function. In this case report we describe a recently published technique to overcome severe radial spasm during transradial coronary angiography in a patient with moderate aortic valve stenosis.

  13. Balloon-Assisted Tracking to Overcome Radial Spasm during Transradial Coronary Angiography: A Case Report

    Directory of Open Access Journals (Sweden)

    N. J. W. Verouden

    2014-01-01

    Full Text Available Spasm of the radial artery is the most important cause of failure to perform coronary angiography via the transradial approach. Spasmolytic cocktail may prevent radial artery spasm but is relatively contraindicated in patients with aortic stenosis or diminished left ventricular function. In this case report we describe a recently published technique to overcome severe radial spasm during transradial coronary angiography in a patient with moderate aortic valve stenosis.

  14. Fragment-based approaches to enzyme inhibition

    OpenAIRE

    Ciulli, Alessio; Abell, Chris

    2007-01-01

    Fragment-based approaches have provided a new paradigm for small-molecule drug discovery. The methodology is complementary to high-throughput screening approaches, starting from fragments of low molecular complexity and high ligand efficiency, and building up to more potent inhibitors. The approach, which depends heavily on a number of biophysical techniques, is now being taken up by more groups in both industry and academia. This article describes key aspects of the process and highlights re...

  15. Clinical application of iopamidol (pamiray 300) for cerebral angiography

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Ho; Suh, Sang Hyun; Kim, Jin Na; Kim, Eung Yeop; Kim, Dong Joon; Lee, Seung Koo; Kim, Dong Ik [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2007-08-15

    The aim of this study was to assess the clinical safety and efficacy of Pamiray 300 (Iopamidol; Dongkook Pharm, Seoul, Korea) as a nonionic contrast medium for cerebral angiography. One hundred patients undergoing cerebral angiography were randomly assigned to receive Pamiray 300 after written consent had been obtained. Patients with adverse reactions were divided into two groups. One group consisted of patients with minor adverse events such as heat sensation and pain, and the other group consisted of patients with major adverse events such as dyspnea, laryngeal edema and shock. The qualities of the radiographic images were stratified into five grades by three independent radiologists. No abnormality induced by Pamiray 300 was seen by a physical and neurological examination, blood pressure measurement, electrocardiogram, respiration rate measurement and partial fraction of arterial oxygen recording. No major and severe adverse events occurred throughout the study. Patient sex, age, disease category, underlying disease and administered contrast dosage showed no statistical significance with regards to the occurrence of adverse events. The opacification of blood vessels in all patients was 'good' or 'excellent'. Based on the results of this study, Pamiray 300 is a safe, efficacious and well-tolerated contrast medium for use in cerebral angiography. Thus, Pamiray 300 can be used as a competitive medium in cerebral angiography.

  16. Flow modification in canine intracranial aneurysm model by an asymmetric stent: studies using digital subtraction angiography (DSA) and image-based computational fluid dynamics (CFD) analyses

    Science.gov (United States)

    Hoi, Yiemeng; Ionita, Ciprian N.; Tranquebar, Rekha V.; Hoffmann, Kenneth R.; Woodward, Scott H.; Taulbee, Dale B.; Meng, Hui; Rudin, Stephen

    2006-03-01

    An asymmetric stent with low porosity patch across the intracranial aneurysm neck and high porosity elsewhere is designed to modify the flow to result in thrombogenesis and occlusion of the aneurysm and yet to reduce the possibility of also occluding adjacent perforator vessels. The purposes of this study are to evaluate the flow field induced by an asymmetric stent using both numerical and digital subtraction angiography (DSA) methods and to quantify the flow dynamics of an asymmetric stent in an in vivo aneurysm model. We created a vein-pouch aneurysm model on the canine carotid artery. An asymmetric stent was implanted at the aneurysm, with 25% porosity across the aneurysm neck and 80% porosity elsewhere. The aneurysm geometry, before and after stent implantation, was acquired using cone beam CT and reconstructed for computational fluid dynamics (CFD) analysis. Both steady-state and pulsatile flow conditions using the measured waveforms from the aneurysm model were studied. To reduce computational costs, we modeled the asymmetric stent effect by specifying a pressure drop over the layer across the aneurysm orifice where the low porosity patch was located. From the CFD results, we found the asymmetric stent reduced the inflow into the aneurysm by 51%, and appeared to create a stasis-like environment which favors thrombus formation. The DSA sequences also showed substantial flow reduction into the aneurysm. Asymmetric stents may be a viable image guided intervention for treating intracranial aneurysms with desired flow modification features.

  17. Computer-based automated left atrium segmentation and volumetry from ECG-gated coronary CT angiography data. Comparison with manual slice segmentation and ultrasound planimetric methods

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, R.W.; Kraus, B.; Kerl, J.M.; Lehnert, T.; Vogl, T.J. [Universitaetsklinikum Frankfurt (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie; Bernhardt, D.; Vega-Higuera, F. [Siemens AG, Healthcare Sector, Forchheim (Germany). Computed Tomography; Ackermann, H. [Universitaetsklinikum Frankfurt (Germany). Inst. fuer Biostatistik und Mathematische Modellierung

    2010-12-15

    Purpose: Enlargement of the left atrium is a risk factor for cardiovascular or cerebrovascular events. We evaluated the performance of prototype software for fully automated segmentation and volumetry of the left atrium. Materials and Methods: In 34 retrospectively ECG-gated coronary CT angiography scans, the end-systolic (LAVsys) and end-diastolic (LAVdia) volume of the left atrium was calculated fully automatically by prototype software. Manual slice segmentation by two independent experienced radiologists served as the reference standard. Furthermore, two independent observers calculated the LAV utilizing two ultrasound planimetric methods ('area length' and 'prolate ellipse') on CTA images. Measurement periods were compared for all methods. Results: The left atrial volumes calculated with the prototype software were in excellent agreement with the results from manual slice segmentation (r = 0.97 - 0.99; p < 0.001; Bland-Altman) with excellent interobserver agreement between both radiologists (r = 0.99; p < 0.001). Ultrasound planimetric methods clearly showed a higher variation (r = 0.72 - 0.86) with moderate interobserver agreement (r = 0.51 - 0.79). The measurement period was significantly lower with the software (267 {+-} 28 sec; p < 0.001) than with ultrasound methods (431 {+-} 68 sec) or manual slice segmentation (567 {+-} 91 sec). Conclusion: The prototype software showed excellent agreement with manual slice segmentation with the least time consumption. This will facilitate the routine assessment of the LA volume from coronary CTA data and therefore risk stratification. (orig.)

  18. Transient cortical blindness after coronary artery angiography.

    Science.gov (United States)

    Terlecki, Michał; Wojciechowska, Wiktoria; Rajzer, Marek; Jurczyszyn, Artur; Bazan-Socha, Stanisława; Bryniarski, Leszek; Czarnecka, Danuta

    2013-01-01

    Coronary angiography is the current gold standard for the diagnosis of ischemic heart disease and therefore the prevalence of percutaneous coronary procedures such as angiography and angioplasty is high. The occurrence of cerebral complications after coronary angiography and coronary angioplasty is low and it mainly includes transient ischemic attack and stroke. The prevalence of transient cortical blindness after X-ray contrast media is low and it is usually seen after cerebral angiography. Until now only a few cases of transient cortical blindness have been described after coronary artery angiography. Regarding the spread of coronary angiography worldwide and in Poland this complication is uniquely rare. A 32-year-old man with multiple extrasystolic ventricular arrhythmia suggesting Brugada syndrome diagnosis according to morphology of the left bundle branch block and with decreased left ventricular ejection fraction was admitted to the First Department of Cardiology and Hypertension, Medical College of the Jagiellonian University in Krakow. Coronary angiography was performed in order to exclude ischemic etiology of the observed abnormalities. No arteriosclerotic lesions were found in coronary arteries. Transient cortical blindness was observed directly after angiography which may have been caused by the neurotoxic effect of the used X-ray contrast medium. In ophthalmologic and neurologic examination as well as in the cerebral computed tomography scan no pathologies were found. Visual impairment disappeared totally within several hours.

  19. MR angiography in abdominal neoplasms

    Energy Technology Data Exchange (ETDEWEB)

    Squillaci, E. [Dept. of Radiology, Rome-2 Univ., Hospital S. Eugenio, Rome (Italy); Crecco, M. [Dept. of Radiology, Cancer Research Inst. (Regina Elena), Rome (Italy); Grandinetti, M.L. [Dept. of Radiology, Cancer Research Inst. (Regina Elena), Rome (Italy); Maspes, F. [Dept. of Radiology, Rome-2 Univ., Hospital S. Eugenio, Rome (Italy); Lo Presti, G. [Dept. of Radiology, Rome-2 Univ., Hospital S. Eugenio, Rome (Italy); Squillaci, S. [Dept. of Radiology, Cancer Research Inst. (Regina Elena), Rome (Italy); Simonetti, G. [Dept. of Radiology, Rome-2 Univ., Hospital S. Eugenio, Rome (Italy)

    1994-10-01

    The role of magnetic resonance angiography (MRA) in the evaluation of vascular involvement was studied in 55 patients with abdominal neoplasms. A 2-D time-of-flight (TOF) technique was used in all patients. All patients underwent CT and MR examinations before MRA. Also, MR angiograms were compared with digital subtraction angiography in 22 cases, with Doppler US in 13 cases, and with surgical findings in 20 cases. In all patients with liver neoplasms (n=29) MRA demonstrated the absence of flow in the infiltrated segments. Pericapsular neovascularization was observed in 12 patients. Portal vein involvement was correctly detected in 27 patients. In all cases MRA demonstrated in relationship between the tumor and venous structures. Portosystemic shunts were visualized in 20 of 21 patients with portal hypertension. Vena cava thrombosis (3 cases), compression (5 cases), and displacement (2 cases) were correctly demonstrated. In renal (n=6) and adrenal gland (n=3) tumors renal vein compression was correctly detected in 2 cases, displacement in 1 case, and thrombosis in 3 cases, with only 1 false-positive finding. In 7 patients with pancreatic tumors MRA demonstrated splenic vein thrombosis in 2 cases and compression in 2 cases, with one false-positive finding. Our results indicate that MRA provides precise information regarding venous vascular involvement in abdominal neoplasms, but preoperative arterial mapping is still problematic. (orig.)

  20. A programmable approach to revising knowledge bases

    Institute of Scientific and Technical Information of China (English)

    LUAN Shangmin; DAI Guozhong; LI Wei

    2005-01-01

    This paper presents a programmable approach to revising knowledge bases consisting of clauses. Some theorems and lemmas are shown in order to give procedures for generating maximally consistent subsets. Then a complete procedure and an incomplete procedure for generating the maximal consistent subsets are presented, and the correctness of the procedures is also shown. Furthermore, a way to implement knowledge base revision is presented, and a prototype system is introduced. Compared with related works, the main characteristic of our approach is that the approach can be implemented by a computer program.

  1. Reduced radiation dose and improved image quality at cardiovascular CT angiography by automated attenuation-based tube voltage selection: intra-individual comparison

    Energy Technology Data Exchange (ETDEWEB)

    Krazinski, Aleksander W.; Silverman, Justin R. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Meinel, Felix G.; Geyer, Lucas L. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Ludwig-Maximilians-University Hospital, Institute for Clinical Radiology, Munich (Germany); Schoepf, U.J. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Canstein, Christian [Siemens Healthcare, CT Division, Malvern, PA (United States); De Cecco, Carlo N. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' - Polo Pontino, Department of Radiological Sciences, Oncology and Pathology, Latina (Italy)

    2014-11-15

    To evaluate the effect of automated tube voltage selection on radiation dose and image quality at cardiovascular CT angiography (CTA). We retrospectively analysed paired studies in 72 patients (41 male, 60.5 ± 16.5 years), who had undergone CTA acquisitions of the heart or aorta both before and after the implementation of an automated x-ray tube voltage selection algorithm (ATVS). All other parameters were kept identical between the two acquisitions. Subjective image quality (IQ) was rated and objective IQ was measured by image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and figure of merit (FOM). Image quality parameters and effective dose were compared between acquisitions. Overall subjective image quality improved with the percentage of cases scored as adequate or higher increasing from 79 % to 92 % after implementation of ATVS (P = 0.03). SNR (14.1 ± 5.9, 15.7 ± 6.1, P = 0.009), CNR (11.6 ± 5.3, 13.2 ± 5.6, P = 0.011), and FOM (19.9 ± 23.3, 43.8 ± 51.1, P < 0.001) were significantly higher after implementation of ATVS. Mean image noise (24.1 ± 8.4 HU, 22.7 ± 7.1 HU, P = 0.048) and mean effective dose (10.6 ± 5.9 mSv, 8.8 ± 5.0 mSv, P = 0.003) were significantly lower after implementation of ATVS. Automated tube voltage selection can operator-independently optimize cardiovascular CTA image acquisition parameters with improved image quality at reduced dose. (orig.)

  2. Comparative evaluation of 64-slice CT angiography and digital subtraction angiography in assessing the cervicocranial vasculature

    Directory of Open Access Journals (Sweden)

    Randolf Klingebiel

    2008-08-01

    Full Text Available Randolf Klingebiel1, Max Kentenich3, Hans-Christian Bauknecht3, Florian Masuhr2, Eberhard Siebert1, Markus Busch2, Georg Bohner11Department of Neuroradiology, 2Department of Neurology, 3Department of Radiology, Charité Universitary Medicine Berlin, GermanyBackground: Noninvasive 64-slice computed tomography angiography (64-MSCTA closely approximates conventional catheter angiography (DSA in terms of detail resolution. Objective: Retrospective evaluation of cervicocranial (cc 64-MSCTA in comparison with DSA in patients with presumptive cc vascular disorders.Material and methods: Twenty-four 64-MSCTA studies (32 mm detector width, slice thickness 0.5 mm, 120 kv, 150 mAs, pitch 0.75 of patients with presumptive cc vascular pathology (13 men, 11 women, mean age 38.3 ± 11.3 yrs, range 19–54 yrs were assessed in comparison with DSA studies without abnormal findings in age-matched patients (11 men, 13 women, mean age 39.7 ± 11.9 yrs, range 18–54 yrs. Study readings were performed in a blinded manner by two neuroradiologists with respect to image quality and assessibility of various cc vascular segments by using a five-point scale. Radiation exposure was calculated for 64-MSCTA.Results: Each reader assessed 384/528 different vessel segments (64-MSCTA/DSA. Superior image quality was attributed to DSA with respect to the C1 ICA–C6 ICA, A3 ACA, and P3 PCA segments as well the AICA and SCA. 64-MSCTA was scored superior for C7 ICA and V4 VA segments. A significantly increased number of nonassessable V2- and V3 VA segments in DSA studies was noted. The effective dose for 64-MSCTA amounted to 2.2 mSv.Conclusions: 64-MSCTA provides near-equivalent diagnostic information of the cc vasculature as compared with DSA. According to our results, DSA should be considered primarily when peripheral vessels (A3/P3 or ICA segments close to the skull base (C2-5 are of interest, such as in primary angiitis or stenoocclusive ICA disease, respectively.Keywords: CT-angiography

  3. Subtraction CT angiography for evaluation of intracranial aneurysms: comparison with conventional CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qi; Li, Kewei; Xie, Peng [The First Affiliated Hospital, Chongqing Medical University, Department of Neurology, Chongqing (China); Lv, Fajin; Li, Yongmei; Luo, Tianyou [The First Affiliated Hospital, Chongqing Medical University, Department of Radiology, Chongqing (China)

    2009-09-15

    The purpose of our study was to compare the diagnostic performance of subtraction computed tomography angiography (CTA) with conventional nonsubtracted CTA and digital subtraction angiography (DSA) for the detection of intracranial aneurysms. A total of 76 patients underwent both subtraction CTA and conventional CTA for the detection and therapy planning of suspected intracranial aneurysms. Subtraction and conventional CTA images were independently assessed by two readers in a blinded manner. The possibility of endovascular treatment or surgical clipping was also assessed based on information provided by CT angiograms alone. In 64 patients, 75 aneurysms were present on DSA. On a per-aneurysm basis, the sensitivity of subtraction CTA was 98.6% for reader 1, and 100% for reader 2. However, sensitivity of conventional CTA was 94.6% for reader 1, and 93.3% for reader 2. Therapeutic decisions could be made regarding 63 patients based on information provided by subtraction CTA images. However, conventional CTA provided sufficient information to make this decision for 55 patients. Conventional CTA has limited sensitivity in detecting very small aneurysms as well as aneurysms adjacent to bone. Subtraction CTA performed on a 64-row multidetector CT is an accurate and promising diagnostic tool that seems to be equivalent to 2D DSA for the detection and pretreatment planning of intracranial aneurysms. (orig.)

  4. Cranial computerized tomography and cerebral angiography in diagnosis of infarction

    Energy Technology Data Exchange (ETDEWEB)

    Zuelich, K.J.

    1988-08-05

    Discussion of the radiological means to further analysis of the pathogenesis of cerebrovascular alterations up to real stroke with infarction. Today in the first place computer-tomography even with contrast means, moreover in the form of 'angio-CT' are used. Localization, size, form, and the grade of tissue destruction may be analyzed. Furthermore perifocal edema and the stage as also the effect of vascular anastomoses for a collateral circulation may be evaluated. Invasive angiography with puncture of carotid and vertebral arteries is used only in special rare indications. Instead, digital computerized angiography (DSA) can be adopted if particular interest is in the study of intracranial arteries, even with an 'invasive' approach, e.g. by femoral catheter (Seldinger). In summarizing: For the analysis of particular problems radiological methods may assist diagnosis and therapy of cerebrovascular infarct.

  5. Dynamic cone beam CT angiography of carotid and cerebral arteries using canine model

    Energy Technology Data Exchange (ETDEWEB)

    Cai Weixing; Zhao Binghui; Conover, David; Liu Jiangkun; Ning Ruola [Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States); Department of Radiology, Shanghai 6th People' s Hospital, 600 Yishan Road, Xuhui, Shanghai (China); Koning Corporation, Lennox Tech Enterprise Center, 150 Lucius Gordon Drive Suite 112, West Henrietta, New York 14586 (United States); Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States); Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States) and Koning Corporation, Lennox Tech Enterprise Center, 150 Lucius Gordon Drive Suite 112, West Henrietta, New York 14586 (United States)

    2012-01-15

    Purpose: This research is designed to develop and evaluate a flat-panel detector-based dynamic cone beam CT system for dynamic angiography imaging, which is able to provide both dynamic functional information and dynamic anatomic information from one multirevolution cone beam CT scan. Methods: A dynamic cone beam CT scan acquired projections over four revolutions within a time window of 40 s after contrast agent injection through a femoral vein to cover the entire wash-in and wash-out phases. A dynamic cone beam CT reconstruction algorithm was utilized and a novel recovery method was developed to correct the time-enhancement curve of contrast flow. From the same data set, both projection-based subtraction and reconstruction-based subtraction approaches were utilized and compared to remove the background tissues and visualize the 3D vascular structure to provide the dynamic anatomic information. Results: Through computer simulations, the new recovery algorithm for dynamic time-enhancement curves was optimized and showed excellent accuracy to recover the actual contrast flow. Canine model experiments also indicated that the recovered time-enhancement curves from dynamic cone beam CT imaging agreed well with that of an IV-digital subtraction angiography (DSA) study. The dynamic vascular structures reconstructed using both projection-based subtraction and reconstruction-based subtraction were almost identical as the differences between them were comparable to the background noise level. At the enhancement peak, all the major carotid and cerebral arteries and the Circle of Willis could be clearly observed. Conclusions: The proposed dynamic cone beam CT approach can accurately recover the actual contrast flow, and dynamic anatomic imaging can be obtained with high isotropic 3D resolution. This approach is promising for diagnosis and treatment planning of vascular diseases and strokes.

  6. Prospectively gated axial CT coronary angiography: preliminary experiences with a novel low-dose technique

    Energy Technology Data Exchange (ETDEWEB)

    Klass, Oliver; Jeltsch, Martin; Feuerlein, Sebastian; Brunner, Horst; Brambs, Hans-Juergen; Hoffmann, Martin H.K. [University Hospital of Ulm, Department of Diagnostic and Interventional Radiology, Ulm (Germany); Nagel, Hans-Dieter [Philips Healthcare, Department of Science and Technology, Hamburg (Germany); Walker, Matthew J. [CT Clinical Science, Philips Healthcare, Cleveland, OH (United States)

    2009-04-15

    To assess image quality and radiation exposure with prospectively gated axial CT coronary angiography (PGA) compared to retrospectively gated helical techniques (RGH). Forty patients with suspected coronary artery disease (CAD) and a stable heart rate below 65 bpm underwent CT coronary angiography (CTCA) using a 64-channel CT system. The patient cohort consisted of 20 consecutive patients examined using a PGA technique and 20 patients examined using a standard RGH technique. Both groups were matched demographically according to age, gender, body mass index, and heart rate. For both groups, two independent observers assessed image quality for all coronary segments on an ordinal scale from 1 (nonassessable) to 5 (excellent quality). Image quality and radiation exposure were compared between patient groups. There were no significant differences in vessel-based image quality between the two groups (P > 0.05). Mean ({+-} SD) effective radiation exposure in the PGA group was 3.7 {+-} 0.8 mSv compared to 18.9 {+-} 3.8 mSv in the RGH group without ECG-based tube current modulation (P < 0.001). Preliminary experience shows PGA technique to be a promising approach for CTCA resulting in a substantial reduction in radiation exposure with image quality comparable to that of standard RGH technique. (orig.)

  7. Photodynamic therapy monitoring with optical coherence angiography

    Science.gov (United States)

    Sirotkina, M. A.; Matveev, L. A.; Shirmanova, M. V.; Zaitsev, V. Y.; Buyanova, N. L.; Elagin, V. V.; Gelikonov, G. V.; Kuznetsov, S. S.; Kiseleva, E. B.; Moiseev, A. A.; Gamayunov, S. V.; Zagaynova, E. V.; Feldchtein, F. I.; Vitkin, A.; Gladkova, N. D.

    2017-01-01

    Photodynamic therapy (PDT) is a promising modern approach for cancer therapy with low normal tissue toxicity. This study was focused on a vascular-targeting Chlorine E6 mediated PDT. A new angiographic imaging approach known as M-mode-like optical coherence angiography (MML-OCA) was able to sensitively detect PDT-induced microvascular alterations in the mouse ear tumour model CT26. Histological analysis showed that the main mechanisms of vascular PDT was thrombosis of blood vessels and hemorrhage, which agrees with angiographic imaging by MML-OCA. Relationship between MML-OCA-detected early microvascular damage post PDT (within 24 hours) and tumour regression/regrowth was confirmed by histology. The advantages of MML-OCA such as direct image acquisition, fast processing, robust and affordable system opto-electronics, and label-free high contrast 3D visualization of the microvasculature suggest attractive possibilities of this method in practical clinical monitoring of cancer therapies with microvascular involvement. PMID:28148963

  8. Computed tomography versus invasive coronary angiography

    DEFF Research Database (Denmark)

    Napp, Adriane E; Haase, Robert; Laule, Michael

    2017-01-01

    OBJECTIVES: More than 3.5 million invasive coronary angiographies (ICA) are performed in Europe annually. Approximately 2 million of these invasive procedures might be reduced by noninvasive tests because no coronary intervention is performed. Computed tomography (CT) is the most accurate noninva...... angiography (ICA) is the reference standard for detection of CAD. • Noninvasive computed tomography angiography excludes CAD with high sensitivity. • CT may effectively reduce the approximately 2 million negative ICAs in Europe. • DISCHARGE addresses this hypothesis in patients with low...

  9. Teaching writing through genre-based approach

    Directory of Open Access Journals (Sweden)

    Luu, Tuan Trong

    2011-01-01

    Full Text Available This research is an endeavour to examine the impact of genre-based approach on students’ writing performance as well as students’ attitudes towards the implementation of genre-based approach in writing learning. Research findings reveal that most of the students gained the control over the key features of the required recount genre in terms of social purposes, language features and schematic structure. The necessity and usefulness of the application of teaching-learning cycle into learning the recount genre was predominantly recognized among students

  10. Burden of hospital admission and repeat angiography in angina pectoris patients with and without coronary artery disease: a registry-based cohort study.

    Directory of Open Access Journals (Sweden)

    Lasse Jespersen

    Full Text Available AIMS: To evaluate risk of hospitalization due to cardiovascular disease (CVD and repeat coronary angiography (CAG in stable angina pectoris (SAP with no obstructive coronary artery disease (CAD versus obstructive CAD, and asymptomatic reference individuals. METHODS AND RESULTS: We followed 11,223 patients with no prior CVD having a first-time CAG in 1998-2009 due to SAP symptoms and 5,695 asymptomatic reference individuals from the Copenhagen City Heart Study through registry linkage for 7.8 years (median. In recurrent event survival analysis, patients with SAP had 3-4-fold higher risk of hospitalization for CVD irrespective of CAG findings and cardiovascular comorbidity. Multivariable adjusted hazard ratios(95%CI for patients with angiographically normal coronary arteries was 3.0(2.5-3.5, for angiographically diffuse non-obstructive CAD 3.9(3.3-4.6 and for 1-3-vessel disease 3.6-4.1(range(all P<0.001. Mean accumulated hospitalization time was 3.5(3.0-4.0(days/10 years follow-up in reference individuals and 4.5(3.8-5.2/7.0(5.4-8.6/6.7(5.2-8.1/6.1(5.2-7.4/8.6(6.6-10.7 in patients with angiographically normal coronary arteries/angiographically diffuse non-obstructive CAD/1-, 2-, and 3-vessel disease, respectively (all P<0.05, age-adjusted. SAP symptoms predicted repeat CAG with multivariable adjusted hazard ratios for patients with angiographically normal coronary arteries being 2.3(1.9-2.9, for angiographically diffuse non-obstructive CAD 5.5(4.4-6.8 and for obstructive CAD 6.6-9.4(range(all P<0.001. CONCLUSIONS: Patients with SAP symptoms and angiographically normal coronary arteries or angiographically diffuse non-obstructive CAD suffer from considerably greater CVD burdens in terms of hospitalization for CVD and repeat CAG compared with asymptomatic reference individuals even after adjustment for cardiac risk factors and exclusion of cardiovascular comorbidity as cause. Contrary to common perception, excluding obstructive CAD by CAG in such

  11. Dependence of Coronary 3-Dimensional Dose Maps on Coronary Topologies and Beam Set in Breast Radiation Therapy: A Study Based on CT Angiographies

    Energy Technology Data Exchange (ETDEWEB)

    Moignier, Alexandra, E-mail: alexandra.moignier@gmail.com [Institut de Radioprotection et de Sûreté Nucléaire, PRP-HOM/SDI/LEDI, Laboratoire d' Evaluation de la Dose Interne, Fontenay-aux-Roses (France); Broggio, David [Institut de Radioprotection et de Sûreté Nucléaire, PRP-HOM/SDI/LEDI, Laboratoire d' Evaluation de la Dose Interne, Fontenay-aux-Roses (France); Derreumaux, Sylvie [Institut de Radioprotection et de Sûreté Nucléaire, PRP-HOM/SER/UEM, Unité d' Expertise en radioprotection Médicale, Fontenay-aux-Roses (France); El Baf, Fida [Institut de Radioprotection et de Sûreté Nucléaire, PRP-HOM/SDI/LEDI, Laboratoire d' Evaluation de la Dose Interne, Fontenay-aux-Roses (France); Mandin, Anne-Marie [Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris, Service de Radiothérapie Oncologique, Paris (France); Girinsky, Théodore [Institut Gustave Roussy, Service de Radiothérapie Oncologique, Villejuif (France); Paul, Jean-François [Centre Chirurgical Marie-Lannelongue, Service de Radiologie, Le Plessis-Robinson (France); and others

    2014-05-01

    Purpose: In left-side breast radiation therapy (RT), doses to the left main (LM) and left anterior descending (LAD) coronary arteries are usually assessed after delineation by prior anatomic knowledge on the treatment planning computed tomography (CT) scan. In this study, dose sensitivity due to interindividual coronary topology variation was assessed, and hot spots were located. Methods and Materials: Twenty-two detailed heart models, created from heart computed tomography angiographies, were fitted into a single representative female thorax. Two breast RT protocols were then simulated into a treatment planning system: the first protocol comprised tangential and tumoral bed beams (TGs{sub T}B) at 50 + 16 Gy, the second protocol added internal mammary chain beams at 50 Gy to TGs{sub T}B (TGs{sub T}B{sub I}MC). For the heart, the LAD, and the LM, several dose indicators were calculated: dose-volume histograms, mean dose (D{sub mean}), minimal dose received by the most irradiated 2% of the volume (D{sub 2%}), and 3-dimensional (3D) dose maps. Variations of these indicators with anatomies were studied. Results: For the LM, the intermodel dispersion of D{sub mean} and D{sub 2%} was 10% and 11%, respectively, with TGs{sub T}B and 40% and 80%, respectively, with TGs{sub T}B{sub I}MC. For the LAD, these dispersions were 19% (D{sub mean}) and 49% (D{sub 2%}) with TGs{sub T}B and 35% (D{sub mean}) and 76% (D{sub 2%}) with TGs{sub T}B{sub I}MC. The 3D dose maps revealed that the internal mammary chain beams induced hot spots between 20 and 30 Gy on the LM and the proximal LAD for some coronary topologies. Without IMC beams, hot spots between 5 and 26 Gy are located on the middle and distal LAD. Conclusions: Coronary dose distributions with hot spot location and dose level can change significantly depending on coronary topology, as highlighted by 3D coronary dose maps. In clinical practice, coronary imaging may be required for a relevant coronary dose assessment

  12. RADIAL ARTERY ANOMALIES IN THE MACEDONIAN POPULATION DURING TRANSRADIAL ANGIOGRAPHY PROCEDURES

    Directory of Open Access Journals (Sweden)

    Zafirovska Biljana

    2016-07-01

    Full Text Available Objective: To assess the incidence of arterial anomalies of the radial artery in the Macedonian population registered during transradial access (TRA angiography procedures in a large series of patients. Background: Transradial angiography (TRA is now the recommended access for percutaneous coronary intervention, but technically is a more challenging approach for angiography procedures mostly due to the anatomic anomalies on the radial artery, which may influence the success rate of transradial angiographic procedures. Methods: All consecutive 19292 patients from our Center, in the period from March 2011 until December 2014 were examined. Preprocedural radial artery angiography was performed in all patients. Clinical and procedure characteristics, type and incidence of vascular anatomy variants and access site complications were analyzed. Results: Anatomical variants were present in 1625 (8.8% patients. The most frequent was high-bifurcating radial artery origin from the axillary and brachial arteries in 1017(5.5% patients, 227 (1.2% had extreme radial artery tortuosity, 176(0.95% had a full radial loop, 32(0.17% with hypoplastic radial artery and 173(0.9% had tortuous brachial, subclavian and axillary arteries. Radial artery spasm was very common in patients with present radial artery anomalies. Conclusion: Radial artery anomalies are very common in the general population. Knowing the anatomy of the radial artery helps the interventional cardiologist in successfully planning and performing this procedure. Radial artery angiography is strongly encouraged in every patient before the begining of the transradial angiography procedures.

  13. Immune based computer virus detection approaches

    Institute of Scientific and Technical Information of China (English)

    TAN Ying; ZHANG Pengtao

    2013-01-01

    The computer virus is considered one of the most horrifying threats to the security of computer systems worldwide.The rapid development of evasion techniques used in virus causes the signature based computer virus detection techniques to be ineffective.Many novel computer virus detection approaches have been proposed in the past to cope with the ineffectiveness,mainly classified into three categories:static,dynamic and heuristics techniques.As the natural similarities between the biological immune system (BIS),computer security system (CSS),and the artificial immune system (AIS) were all developed as a new prototype in the community of anti-virus research.The immune mechanisms in the BIS provide the opportunities to construct computer virus detection models that are robust and adaptive with the ability to detect unseen viruses.In this paper,a variety of classic computer virus detection approaches were introduced and reviewed based on the background knowledge of the computer virus history.Next,a variety of immune based computer virus detection approaches were also discussed in detail.Promising experimental results suggest that the immune based computer virus detection approaches were able to detect new variants and unseen viruses at lower false positive rates,which have paved a new way for the anti-virus research.

  14. Ecosystem based approaches to climate adaptation

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Jensen, Anne; Termansen, Mette

    This report analyses the prospects and barriers of applying ecosystem based approaches systematically to climate adaptation in urban areas, taking the case of green roofs in Copenhagen Municipality. It looks at planning aspects of green roofs in Copenhagen as well as citizen views and preferences...

  15. Ugi-based approaches to quinoxaline libraries.

    Science.gov (United States)

    Azuaje, Jhonny; El Maatougui, Abdelaziz; García-Mera, Xerardo; Sotelo, Eddy

    2014-08-11

    An expedient and concise Ugi-based unified approach for the rapid assembly of quinoxaline frameworks has been developed. This convergent and versatile method uses readily available commercial reagents, does not require advanced intermediates, and exhibits excellent bond-forming efficiency, thus exemplifying the operationally simple synthesis of quinoxaline libraries.

  16. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA is a noninvasive test ... of the major blood vessels throughout your body. It may be performed with or without contrast material ...

  17. Advanced Approach of Multiagent Based Buoy Communication

    Science.gov (United States)

    Gricius, Gediminas; Drungilas, Darius; Andziulis, Arunas; Dzemydiene, Dale; Voznak, Miroslav; Kurmis, Mindaugas; Jakovlev, Sergej

    2015-01-01

    Usually, a hydrometeorological information system is faced with great data flows, but the data levels are often excessive, depending on the observed region of the water. The paper presents advanced buoy communication technologies based on multiagent interaction and data exchange between several monitoring system nodes. The proposed management of buoy communication is based on a clustering algorithm, which enables the performance of the hydrometeorological information system to be enhanced. The experiment is based on the design and analysis of the inexpensive but reliable Baltic Sea autonomous monitoring network (buoys), which would be able to continuously monitor and collect temperature, waviness, and other required data. The proposed approach of multiagent based buoy communication enables all the data from the costal-based station to be monitored with limited transition speed by setting different tasks for the agent-based buoy system according to the clustering information. PMID:26345197

  18. Advanced Approach of Multiagent Based Buoy Communication

    Directory of Open Access Journals (Sweden)

    Gediminas Gricius

    2015-01-01

    Full Text Available Usually, a hydrometeorological information system is faced with great data flows, but the data levels are often excessive, depending on the observed region of the water. The paper presents advanced buoy communication technologies based on multiagent interaction and data exchange between several monitoring system nodes. The proposed management of buoy communication is based on a clustering algorithm, which enables the performance of the hydrometeorological information system to be enhanced. The experiment is based on the design and analysis of the inexpensive but reliable Baltic Sea autonomous monitoring network (buoys, which would be able to continuously monitor and collect temperature, waviness, and other required data. The proposed approach of multiagent based buoy communication enables all the data from the costal-based station to be monitored with limited transition speed by setting different tasks for the agent-based buoy system according to the clustering information.

  19. Heterogeneity of tumor vasculature and antiangiogenic intervention: insights from MR angiography and DCE-MRI.

    Directory of Open Access Journals (Sweden)

    Wenlian Zhu

    Full Text Available PURPOSE: Solid tumor vasculature is highly heterogeneous, which presents challenges to antiangiogenic intervention as well as the evaluation of its therapeutic efficacy. The aim of this study is to evaluate the spatial tumor vascular changes due to bevacizumab/paclitaxel therapy using a combination approach of MR angiography and DCE-MRI method. EXPERIMENTAL DESIGN: Tumor vasculature of MCF-7 breast tumor mouse xenografts was studied by a combination of MR angiography and DCE-MRI with albumin-Gd-DTPA. Tumor macroscopic vasculature was extracted from the early enhanced images. Tumor microvascular parameters were obtained from the pharmacokinetic modeling of the DCE-MRI data. A spatial analysis of the microvascular parameters based on the macroscopic vasculature was used to evaluate the changes of the heterogeneous vasculature induced by a 12 day bevacizumab/paclitaxel treatment in mice bearing MCF-7 breast tumor. RESULTS: Macroscopic vessels that feed the tumors were not affected by the bevacizumab/paclitaxel combination therapy. A higher portion of the tumors was within close proximity of these macroscopic vessels after the treatment, concomitant with tumor growth retardation. There was a significant decrease in microvascular permeability and vascular volume in the tumor regions near these vessels. CONCLUSION: Bevacizumab/paclitaxel combination therapy did not block the blood supply to the MCF-7 breast tumor. Such finding is consistent with the modest survival benefits of adding bevacizumab to current treatment regimens for some types of cancers.

  20. Surgical approaches for tongue base schwannoma.

    Science.gov (United States)

    Ying, Binbin; Zhu, Songsong; Qiao, Yang; Ye, Weimin; Maimaiti, Abdikerimjian; Hu, Jingzhou; Zhang, Yong

    2013-01-01

    Schwannomas (neurilemmomas) are benign nerve sheath tumor originating from Schwann cells. They are well circumscribed and rarely infiltrate and metastasize. Schwannomas of the head and neck commonly occur in the tongue followed by the palate, floor of mouth, buccal mucosa, and mandible. Tongue base schwannomas could extend to the pharyngeal cavity or the floor of the mouse, and it is difficult to differentiate between tumors of the lingual, hypoglossal, and glossopharyngeal nerves.Surgical treatment of tongue base schwannomas is difficult because of limited operative exposure. Although mandibulotomy with lip splitting could obtain good exposure, surgeons might strike a balance between exposure obtaining and morbidity following because there are intricate neurovascular anatomical relationships in this region, and mandibulotomy with lip splitting would cause significant morbidity. Surgical approach options are important for tongue base schwannoma removal. From March 2008 to March 2010, 8 patients were clinically and pathologically diagnosed with tongue base schwannomas in our department, and all underwent surgical treatment. In our experience, transoral approach was used for tongue base schwannomas extending to the floor of the mouse and suprahyroid pharyngotomy approach for those extending to the pharyngeal cavity. Follow-up was made until now. One patient who experienced transoral excision still experienced numbness in the region of the lateral tongue tip, and the other 7 patients had no postoperative long-term complications.

  1. Managing projects a team-based approach

    CERN Document Server

    Brown, Karen A

    2010-01-01

    Students today are likely to be assigned to project teams or to be project managers almost immediately in their first job. Managing Projects: A Team-Based Approach was written for a wide range of stakeholders, including project managers, project team members, support personnel, functional mangers who provide resources for projects, project customers (and customer representatives), project sponsors, project subcontractors, and anyone who plays a role in the project delivery process. The need for project management is on the rise as product life cycles compress, demand for IT systems increases, and business takes on an increasingly global character. This book adds to the project management knowledge base in a way that fills an unmet need—it shows how teams can apply many of the standard project management tools, as well as several tools that are relatively new to the field. Managing Projects: A Team-Based Approach offers the academic rigor found in most textbooks along with the practical attributes often foun...

  2. An Approach to Programming Based on Concepts

    CERN Document Server

    Savinov, Alexandr

    2007-01-01

    In this paper we describe a new approach to programming which generalizes object-oriented programming. It is based on using a new programming construct, called concept, which generalizes classes. Concept is defined as a pair of two classes: one reference class and one object class. Each concept has a parent concept which is specified using inclusion relation generalizing inheritance. We describe several important mechanisms such as reference resolution, context stack, dual methods and life-cycle management, inheritance and polymorphism. This approach to programming is positioned as a new programming paradigm and therefore we formulate its main principles and rules.

  3. A network approach based on cliques

    Science.gov (United States)

    Fadigas, I. S.; Pereira, H. B. B.

    2013-05-01

    The characterization of complex networks is a procedure that is currently found in several research studies. Nevertheless, few studies present a discussion on networks in which the basic element is a clique. In this paper, we propose an approach based on a network of cliques. This approach consists not only of a set of new indices to capture the properties of a network of cliques but also of a method to characterize complex networks of cliques (i.e., some of the parameters are proposed to characterize the small-world phenomenon in networks of cliques). The results obtained are consistent with results from classical methods used to characterize complex networks.

  4. Numerical reconstruction of pulsatile blood flow from 4D computer tomography angiography data

    CERN Document Server

    Lovas, Attila; Csobo, Elek; Szilágyi, Brigitta; Sótonyi, Péter

    2015-01-01

    We present a novel numerical algorithm developed to reconstuct pulsatile blood flow from ECG-gated CT angiography data. A block-based optimization method was constructed to solve the inverse problem corresponding to the Riccati-type ordinary differential equation that can be deduced from conservation principles and Hooke's law. Local flow rate for 5 patients was computed in 10cm long aorta segments that are located 1cm below the heart. The wave form of the local flow rate curves seems to be realistic. Our approach is suitable for estimating characteristics of pulsatile blood flow in aorta based on ECG gated CT scan thereby contributing to more accurate description of several cardiovascular lesions.

  5. Meta-analysis: diagnostic accuracy of coronary CT angiography with prospective ECG gating based on step-and-shoot, Flash and volume modes for detection of coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Linfeng; Zhou, Tao; Zhang, Ruijie; Peng, Zhaohui; Ding, Juan; Wang, Sen; Li, Min; Sun, Gang [Jinan Military General Hospital, Department of Medical Imaging, Jinan, Shandong Province (China); Xu, Lin [Jinan Military General Hospital, Department of Medical Cardiology, Jinan, Shandong Province (China)

    2014-10-15

    To investigate the diagnostic performance of coronary computed tomographic angiography (CCTA) with prospective electrocardiograph (ECG) gating based on step-and-shoot (SAS), Flash and volume imaging modes. We searched the electronic databases PubMed for all published studies regarding CCTA. We used an exact binomial rendition of the bivariate mixed-effects regression model developed for synthesis of diagnostic data. A total of 21,852 segments, 4,851 vessels and 1,375 patients were identified using database searches. Patient-level pooled sensitivity was 0.99 (95 % confidence interval [CI], 0.98-1.00); specificity was 0.88 (CI, 0.85-0.91). The results showed that the sensitivity and specificity for detection of significant stenosis did not differ in the three protocols (P = 0.24). No heterogeneity was found at the patient level for sensitivity (Q = 26.23; P = 0.12; I {sup 2} = 27.56 % [CI, 0.00-67.02 %]) and specificity (Q = 19.54; P = 0.42; I {sup 2} = 2.78 % [CI, 0.00-66.26 %]). CCTA with prospective ECG gating has similar high diagnostic value to rule out CAD in all three presented modes. (orig.)

  6. Diagnostic yield and accuracy of CT angiography, MR angiography, and digital subtraction angiography for detection of macrovascular causes of intracerebral haemorrhage: prospective, multicentre cohort study

    OpenAIRE

    van Asch, Charlotte J. J.; Birgitta K Velthuis; Rinkel, Gabriël J E; Algra, Ale; de Kort, Gerard A. P.; Witkamp, Theo D.; de Ridder, Johanna C M; van Nieuwenhuizen, Koen M.; De Leeuw, Frank Erik; Schonewille, Wouter J.; de Kort, Paul L. M.; Dippel, Diederik W; Raaymakers, Theodora W M; Hofmeijer, Jeannette; Wermer, Marieke J. H.

    2015-01-01

    Study question What are the diagnostic yield and accuracy of early computed tomography (CT) angiography followed by magnetic resonance imaging/angiography (MRI/MRA) and digital subtraction angiography (DSA) in patients with non-traumatic intracerebral haemorrhage? Methods This prospective diagnostic study enrolled 298 adults (18-70 years) treated in 22 hospitals in the Netherlands over six years. CT angiography was performed within seven days of haemorrhage. If the result was negative, MRI/MR...

  7. Trait-based approaches to zooplankton communities

    DEFF Research Database (Denmark)

    Lichtman, E.; Ohman, M.D.; Kiørboe, Thomas

    2013-01-01

    Zooplankton are major primary consumers and predators in most aquatic ecosystems. They exhibit tremendous diversity of traits, ecological strategies and, consequently, impacts on other trophic levels and the cycling of materials and energy. An adequate representation of this diversity in community...... and ecosystem models is necessary to generate realistic predictions on the functioning of aquatic ecosystems but remains extremely challenging. We propose that the use of trait-based approaches is a promising way to reduce complexity while retaining realism in developing novel descriptions of zooplankton...... traits, such as body size and motility, transcend several functions and are major determinants of zooplankton ecological strategies. Future developments of trait-based approaches to zooplankton should assemble a comprehensive matrix of key traits for diverse groups and explore it for general patterns...

  8. Materiality in a practice-based approach

    DEFF Research Database (Denmark)

    Svabo, Connie

    2009-01-01

    The paper provides an overview of the vocabulary for materiality which is used by practice-based approaches to organizational knowing. Common terms for materiality are 'artifact' and 'object'. The interaction between social and material realities is grasped as several processes: object-oriented a......The paper provides an overview of the vocabulary for materiality which is used by practice-based approaches to organizational knowing. Common terms for materiality are 'artifact' and 'object'. The interaction between social and material realities is grasped as several processes: object......-oriented activity, symbolization, embodiment, performance, alignment and mediation. Material artifacts both stabilize and destabilize organizational action. They may ensure coordination, communication, and control, but they may also create disturbance and conflict....

  9. Computed tomographic angiography or conventional coronary angiography in therapeutic decision-making

    NARCIS (Netherlands)

    Piers, Lieuwe H.; Dikkers, Riksta; Willems, Tineke P.; de Smet, Bart J. G. L.; Oudkerk, Matthijs; Zijlstra, Felix; Tio, Rene A.

    2008-01-01

    To evaluate non-invasive angiography using dual-source computed tomography (CT) for the determination of the most appropriate therapeutic strategy in patients with suspected coronary artery disease (CAD). CT angiography (Dual Source CT, Somatom Definition, Siemens Medical Systems, Forchheim, Germany

  10. Dynamic magnetic resonance angiography for localization of hyperfunctioning parathyroid glands in the reoperative neck

    Energy Technology Data Exchange (ETDEWEB)

    Aschenbach, R., E-mail: rene.aschenbach@helios-kliniken.de [HELIOS Hospital Erfurt, Department of Diagnostic and Interventional Radiology and Neuroradiology, Nordhaeuser Str. 74, 99089 Erfurt (Germany); Tuda, S. [HELIOS Hospital Erfurt, Department of Diagnostic and Interventional Radiology and Neuroradiology, Nordhaeuser Str. 74, 99089 Erfurt (Germany); Lamster, E.; Meyer, A. [HELIOS Hospital Erfurt, Department of Endocrinology, Nordhaeuser Str. 74, 99089 Erfurt (Germany); Roediger, H.; Stier, A. [HELIOS Hospital Erfurt, Department of Visceral Surgery, Nordhaeuser Str. 74, 99089 Erfurt (Germany); Conrad, E. [HELIOS Hospital Erfurt, Department of Nuclear Medicine, Nordhaeuser Str. 74, 99089 Erfurt (Germany); Basche, S.; Klisch, J. [HELIOS Hospital Erfurt, Department of Diagnostic and Interventional Radiology and Neuroradiology, Nordhaeuser Str. 74, 99089 Erfurt (Germany); Vogl, T.J. [University Hospital Frankfurt/Main, Center of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt/Main (Germany)

    2012-11-15

    Objectives: To evaluate the use of dynamic magnetic resonance angiography for localization of hyperfunctioning parathyroid glands in the reoperative neck. Methods: We retrospectively evaluated the head-neck MRIs of 30 patients with a history of hyperparathyroidism, prior head-neck surgery, and intraoperative proven adenomas. The protocol included conventional imaging with T2-weighted STIR sequences, T1w axial and coronal prior to and after contrast media administration, and dynamic magnetic resonance angiography. We compared the results from MRI, dynamic magnetic resonance angiography with 99m-Tc-Sestamibi with intraoperative findings as the gold standard. Results: In conventional MRI 19/30 true positives were detected with a sensitivity and specificity of 63.3% and 100%, respectively. However, by adding dynamic magnetic resonance angiography the detection rate increased to 28/30 true positives. Based on intraoperative findings, the sensitivity and specificity of dynamic magnetic resonance angiography were 93.3% and 100%, respectively. 99m-Tc-Sestamibi detected 24/30 true positives, sensitivity was 80%. Conclusion: The diagnostic value of MRI including dynamic magnetic resonance angiography is superior to MRI alone and superior to that of 99m-Tc-Sestamibi in the diagnostic workup of hyperfunctioning parathyroid glands when compared against intraoperative findings.

  11. Stem cell-based approaches in dentistry

    OpenAIRE

    Mitsiadis, T A; Orsini, G.; Jimenez-Rojo, L

    2015-01-01

    Repair of dental pulp and periodontal lesions remains a major clinical challenge. Classical dental treatments require the use of specialised tissue-adapted materials with still questionable efficacy and durability. Stem cell-based therapeutic approaches could offer an attractive alternative in dentistry since they can promise physiologically improved structural and functional outcomes. These therapies necessitate a sufficient number of specific stem cell populations for implantation. Dental m...

  12. An Approach to Programming Based on Concepts

    OpenAIRE

    Savinov, Alexandr

    2007-01-01

    In this paper we describe a new approach to programming which generalizes object-oriented programming. It is based on using a new programming construct, called concept, which generalizes classes. Concept is defined as a pair of two classes: one reference class and one object class. Each concept has a parent concept which is specified using inclusion relation generalizing inheritance. We describe several important mechanisms such as reference resolution, context stack, dual methods and life-cy...

  13. Tourism Planning: A Case Based Approach

    Directory of Open Access Journals (Sweden)

    Muhammad Khalid Khan

    2014-06-01

    Full Text Available This study is an attempt to investigate the tourism marketing and attraction strategies adopted by various countries. A case study based approach is adopted in this study. On the basis of investigation of tourism development strategies adopted by various countries, suggestions are also made at the end. These suggestions are aimed to increase visitors our tourists’ base in a country. These suggestions can be used by any country to increase visitors or tourists. Future directions are also given at the end.

  14. Mono-Energy Coronary Angiography with a Compact Synchrotron Source

    Science.gov (United States)

    Eggl, Elena; Mechlem, Korbinian; Braig, Eva; Kulpe, Stephanie; Dierolf, Martin; Günther, Benedikt; Achterhold, Klaus; Herzen, Julia; Gleich, Bernhard; Rummeny, Ernst; Noёl, Peter B.; Pfeiffer, Franz; Muenzel, Daniela

    2017-02-01

    X-ray coronary angiography is an invaluable tool for the diagnosis of coronary artery disease. However, the use of iodine-based contrast media can be contraindicated for patients who present with chronic renal insufficiency or with severe iodine allergy. These patients could benefit from a reduced contrast agent concentration, possibly achieved through application of a mono-energetic x-ray beam. While large-scale synchrotrons are impractical for daily clinical use, the technology of compact synchrotron sources strongly advanced during the last decade. Here we present a quantitative analysis of the benefits a compact synchrotron source can offer in coronary angiography. Simulated projection data from quasi-mono-energetic and conventional x-ray tube spectra is used for a CNR comparison. Results show that compact synchrotron spectra would allow for a significant reduction of contrast media. Experimentally, we demonstrate the feasibility of coronary angiography at the Munich Compact Light Source, the first commercial installation of a compact synchrotron source.

  15. Computed tomography angiography in patients with active gastrointestinal bleeding

    Energy Technology Data Exchange (ETDEWEB)

    Reis, Fatima Regina Silva; D' Ippolito, Giuseppe, E-mail: fatima.rsreis@gmail.com [Universidade Federal de Sao Paulo (EPM/UNIFESP), Sao Paulo, SP (Brazil). Escola Paulista de Medicina; Cardia, P.P. [Hospital Vera Cruz, Campinas, SP (Brazil)

    2015-11-15

    Gastrointestinal bleeding represents a common medical emergency, with considerable morbidity and mortality rates, and a prompt diagnosis is essential for a better prognosis. In such a context, endoscopy is the main diagnostic tool; however, in cases where the gastrointestinal hemorrhage is massive, the exact bleeding site might go undetected. In addition, a trained professional is not always present to perform the procedure. In an emergency setting, optical colonoscopy presents limitations connected with the absence of bowel preparation, so most of the small bowel cannot be assessed. Scintigraphy cannot accurately demonstrate the anatomic location of the bleeding and is not available at emergency settings. The use of capsule endoscopy is inappropriate in the acute setting, particularly in the emergency department at night, and is a highly expensive method. Digital angiography, despite its high sensitivity, is invasive, presents catheterization-related risks, in addition to its low availability at emergency settings. On the other hand, computed tomography angiography is fast, widely available and minimally invasive, emerging as a promising method in the diagnostic algorithm of these patients, being capable of determining the location and cause of bleeding with high accuracy. Based on a critical literature review and on their own experience, the authors propose a computed tomography angiography protocol to assess the patient with gastrointestinal bleeding. (author)

  16. Ectopic Origin of Coronary Arteries Diagnozed by Coronary Angiography

    Science.gov (United States)

    Krasniqi, Xhevdet; Gorani, Daut; Sejdiu, Basri; Citaku, Hajdin

    2016-01-01

    Introduction: Anomalous origin of coronary arteries from opposite sinus of Valsalva is rare finding. The incidence of anomalous origination of the left coronary artery from right sinus is 0.15% and the right coronary artery from the left sinus is 0.92%. The ectopic origin of left coronary artery or right coronary artery from opposite sinus depending on pathways and considering atherosclerotic changes are manifested with different clinical significance. Case report: We report two cases, the first case the coronary angiography showed the left coronary artery arising from the right coronary sinus, presenting with proximally and distally stenosed left anterior descending artery (LAD), associated with medial and distal stenosed right coronary artery (RCA). The second case the coronary angiography revealed the right coronary artery arising from the left coronary sinus, associated with tortuous medial and distal segments of left anterior descending artery (LAD), without atherosclerotic changes. The first case successfully underwent treatment procedures based on guidelines for revascularization. Conclusion: The coronary angiography of patients with coronary ischemia determines atherosclerotic disease with possibility of the presence of coronary artery anomalies that in cases with ectopic origin from opposite sinus continues to exist as a challenge during treatment in interventional cardiology. PMID:27482140

  17. MR angiography in diagnosis of subarachnoidal hemorrhage; Angiografia rezonansu magnetycznego w diagnostyce przyczyn krwotoku podpajeczynowkowego

    Energy Technology Data Exchange (ETDEWEB)

    Paprzycki, W.; Gradzki, J.; Sosnowski, P.; Stajgis, M.; Mularek, J.; Mularek, O. [Osrodek Diagnostyki Obrazowej IR, Akademia Medyczna, Poznan (Poland)]|[Zaklad Neuroradiologii, Akademia Medyczna, Poznan (Poland)]|[Klinika Neurologii, Akademia Medyczna, Poznan (Poland)

    1994-12-31

    During 1 year 34 patients with subarachnoidal hemorrhage history have been examined by MR angiography (MRA). MRA was obtained with a 1.0 T Magnetom Impact system (Simens) using gradient-echo FISP 3D and FLASH 2D sequences. Additional spin-echo sequences were used in group of 23 patients. Conventional angiography (CA) from direct common carotid artery approach was also performed in 25 patients, in 14 patients vertebral angiography using Seldinger technique from femoral artery approach was additionally executed. Presence of 18 intracranial aneurysms was confirmed in 16 patients, diagnosis of arteriovenous hemangioma was established in 8 cases. 7 patients with aneurysms were operated on the basis of MRA images only. There were not significant diagnostic differences between MRA and CA images in this material. (author) 9 refs, 6 figs, 3 tabs

  18. MR angiography in tuberculous meningitis

    Energy Technology Data Exchange (ETDEWEB)

    Kalita, Jayantee; Prasad, Sreeram; Maurya, Pradeep K.; Misra, Usha K. (Dept. of Neurology, Sanjay Gandhi Post Graduate Inst. of Medical Sciences, Lucknow (India)), Email: drukmisra@rediffmail.com; Kumar, Sunil (Dept. of Radiodiagnosis, Sanjay Gandhi Post Graduate Inst. of Medical Sciences, Lucknow (India))

    2012-04-15

    Background: Infarctions in tuberculous meningitis (TBM) are common but there is a paucity of studies on MR angiography (MRA). Purpose: To evaluate the pattern and predictors of MRA abnormality in patients with TBM. Material and Methods: Sixty-seven patients with TBM were subjected to clinical, laboratory, magnetic resonance imaging (MRI), and MRA evaluation. The severity of meningitis, focal deficit, CSF findings, and stroke co-morbidities were recorded. Presence of exudates, infarction, hydrocephalous, and tuberculoma on MRI were noted. On intracranial MRA, occlusion or more than 50% narrowing of proximal middle cerebral artery (MCA), anterior cerebral artery (ACA) and posterior cerebral artery (PCA), and basilar artery were considered abnormal. The MRA abnormality was correlated with clinical, laboratory, and MRI findings. Results: Sixty-seven patients, aged 3-75 years (median 34 years) were included. MRI was abnormal in 61 (91%) patients; basal exudates in 24, hydrocephalous in 23, tuberculoma in 33, and infarction in 40. MRA was abnormal in 34 (50.7%); MCA was most commonly involved (n = 21), followed by PCA (n = 14), ICA (n = 8), ACA (n 5), basilar artery (n = 5), and vertebral and superior cerebellar artery (1 each). One-fourth of the patients had abnormality in both anterior and posterior circulations. MRA abnormality was related to hydrocephalous and infarction; corresponding infarct was present in 61.8% patients; 41.7% patients with abnormal MRA developed infarct at 3 months but none with normal MRA. Conclusion: Half the patients with TBM had MRA abnormality involving both anterior and posterior circulations and 61.8% of them had corresponding infarcts

  19. Doppler Fourier Domain Optical Coherence Tomography for Label-Free Tissue Angiography

    Science.gov (United States)

    Leitgeb, Rainer A.; Szkulmowski, Maciej; Blatter, Cedric; Wojtkowski, Maciej

    Information about tissue perfusion and the vascular structure is certainly most important for assessment of tissue state or personal health and the diagnosis of any pathological conditions. It is therefore of key medical interest to have tools available for both quantitative blood flow assessment as well as qualitative vascular imaging. The strength of optical techniques is the unprecedented level of detail even for small capillary structures or microaneurysms and the possibility to combine different techniques for additional tissue spectroscopy giving insight into tissue metabolism. There is an immediate diagnostic and pharmacological demand for high-resolution, label-free, tissue angiography and flow assessment that in addition allow for precise depth gating of flow information. The most promising candidate is Doppler optical coherence tomography (DOCT) being noncontact, label free, and without employing hazardous radiation. DOCT provides fully quantitative volumetric information about blood flow together with the vascular and structural anatomy. Besides flow quantification, analysis of OCT signal fluctuations allows to contrast moving scatterers in tissue such as red blood cells from static tissue. This allows for non-invasive optical angiography and yields high resolution even for smallest capillaries. Because of the huge potential of DOCT and lable-free optical angiography for diagnosis, the last years saw a rapid increase of publications in this field with many different approaches. The present chapter gives an overview over existing Doppler OCT approaches and angiography techniques. It furthermore discusses limitations and noise issues, and gives examples for angiography in the eye and the skin.

  20. Coherent bremsstrahlung used for digital subtraction angiography

    Science.gov (United States)

    Überall, Herbert

    2007-05-01

    Digital subtraction angiography (DSA), also known as Dichromography, using synchrotron radiation beams has been developed at Stanford University (R. Hofstadter) and was subsequently taken over at the Brookhaven Synchrotron and later at Hamburg (HASYLAB) [see, e.g., W.R. Dix, Physik in unserer Zeit. 30 (1999) 160]. The imaging of coronary arteries is carried out with an iodine-based contrast agent which need not be injected into the heart. The radiation must be monochromatized and is applied above and below the K-edge of iodine (33.16 keV), with a subsequent digital subtraction of the two images. Monochromatization of the synchrotron radiation causes a loss of intensity of 10 -3. We propose instead the use of coherent bremsstrahlung [see, e.g., A.W. Saenz and H. Uberall, Phys. Rev. B25 (1982) 448] which is inherently monochromatic, furnishing a flux of 10 12 photon/sec. This requires a 10-20 MeV electron linac which can be obtained by many larger hospitals, eliminating the scheduling problems present at synchrotrons. The large, broad incoherent bremsstrahlung background underlying the monochromatic spike would lead to inadmissible overexposure of the patient. This problem can be solved with the use of Kumakhov's capillary optics [see e.g., S.B.Dabagov, Physics-Uspekhi 46 (2003) 1053]: the low-energy spiked radiation can be deflected towards the patient, while the higher energy incoherent background continues forward, avoiding the patient who is placed several meters from the source.

  1. Microfocal angiography of the pulmonary vasculature

    Science.gov (United States)

    Clough, Anne V.; Haworth, Steven T.; Roerig, David T.; Linehan, John H.; Dawson, Christopher A.

    1998-07-01

    X-ray microfocal angiography provides a means of assessing regional microvascular perfusion parameters using residue detection of vascular indicators. As an application of this methodology, we studied the effects of alveolar hypoxia, a pulmonary vasoconstrictor, on the pulmonary microcirculation to determine changes in regional blood mean transit time, volume and flow between control and hypoxic conditions. Video x-ray images of a dog lung were acquired as a bolus of radiopaque contrast medium passed through the lobar vasculature. X-ray time-absorbance curves were acquired from arterial and microvascular regions-of-interest during both control and hypoxic alveolar gas conditions. A mathematical model based on indicator-dilution theory applied to image residue curves was applied to the data to determine changes in microvascular perfusion parameters. Sensitivity of the model parameters to the model assumptions was analyzed. Generally, the model parameter describing regional microvascular volume, corresponding to area under the microvascular absorbance curve, was the most robust. The results of the model analysis applied to the experimental data suggest a significant decrease in microvascular volume with hypoxia. However, additional model assumptions concerning the flow kinematics within the capillary bed may be required for assessing changes in regional microvascular flow and mean transit time from image residue data.

  2. Matched filter based iterative adaptive approach

    Science.gov (United States)

    Nepal, Ramesh; Zhang, Yan Rockee; Li, Zhengzheng; Blake, William

    2016-05-01

    Matched Filter sidelobes from diversified LPI waveform design and sensor resolution are two important considerations in radars and active sensors in general. Matched Filter sidelobes can potentially mask weaker targets, and low sensor resolution not only causes a high margin of error but also limits sensing in target-rich environment/ sector. The improvement in those factors, in part, concern with the transmitted waveform and consequently pulse compression techniques. An adaptive pulse compression algorithm is hence desired that can mitigate the aforementioned limitations. A new Matched Filter based Iterative Adaptive Approach, MF-IAA, as an extension to traditional Iterative Adaptive Approach, IAA, has been developed. MF-IAA takes its input as the Matched Filter output. The motivation here is to facilitate implementation of Iterative Adaptive Approach without disrupting the processing chain of traditional Matched Filter. Similar to IAA, MF-IAA is a user parameter free, iterative, weighted least square based spectral identification algorithm. This work focuses on the implementation of MF-IAA. The feasibility of MF-IAA is studied using a realistic airborne radar simulator as well as actual measured airborne radar data. The performance of MF-IAA is measured with different test waveforms, and different Signal-to-Noise (SNR) levels. In addition, Range-Doppler super-resolution using MF-IAA is investigated. Sidelobe reduction as well as super-resolution enhancement is validated. The robustness of MF-IAA with respect to different LPI waveforms and SNR levels is also demonstrated.

  3. A stepwise approach to the visual interpretation of CT-based myocardial perfusion.

    Science.gov (United States)

    Mehra, Vishal C; Valdiviezo, Carolina; Arbab-Zadeh, Armin; Ko, Brian S; Seneviratne, Sujith K; Cerci, Rodrigo; Lima, Joao A C; George, Richard T

    2011-01-01

    Cardiovascular anatomic and functional testing have been longstanding and key components of cardiac risk assessment. As part of that strategy, CT-based imaging has made steady progress, with coronary computed tomography angiography (CTA) now established as the most sensitive noninvasive strategy for assessment of significant coronary artery disease. Myocardial CT perfusion imaging (CTP), as the functional equivalent of coronary CTA, is being tested in currently ongoing multicenter trials and is proposed to enhance the accuracy of coronary CTA alone. However, unlike coronary CTA that has published guidelines for interpretation and is rapidly gaining applicability in the noninvasive risk assessment paradigms, myocardial CTP is rapidly evolving, and guidance on a standard approach to its interpretation is lacking. In this article we describe a practical stepwise approach for interpretation of myocardial CTP that should add to the clinical applicability of this modality. These steps include (1) coronary CTA interpretation for potentially obstructive atherosclerosis, (2) reconstruction and preprocessing of myocardial CTP images, (3) image quality assessment and the identification of potentially confounding artifacts, (4) rest and stress image interpretation for enhancement patterns and areas of hypoattenuation, and (5) correlation of coronary anatomy and myocardial perfusion deficits. This systematic review uses already published methods from multiple clinical studies and is intended for general usage, independent of the platform used for image acquisition.

  4. Cosine-Based Clustering Algorithm Approach

    Directory of Open Access Journals (Sweden)

    Mohammed A. H. Lubbad

    2012-02-01

    Full Text Available Due to many applications need the management of spatial data; clustering large spatial databases is an important problem which tries to find the densely populated regions in the feature space to be used in data mining, knowledge discovery, or efficient information retrieval. A good clustering approach should be efficient and detect clusters of arbitrary shapes. It must be insensitive to the outliers (noise and the order of input data. In this paper Cosine Cluster is proposed based on cosine transformation, which satisfies all the above requirements. Using multi-resolution property of cosine transforms, arbitrary shape clusters can be effectively identified at different degrees of accuracy. Cosine Cluster is also approved to be highly efficient in terms of time complexity. Experimental results on very large data sets are presented, which show the efficiency and effectiveness of the proposed approach compared to other recent clustering methods.

  5. Left ventricular volume determined from scintigraphy and digital angiography by a semi-automated geometric method

    Energy Technology Data Exchange (ETDEWEB)

    Seldin, D.W.; Esser, P.D.; Nichols, A.B.; Ratner, S.J.; Alderson, P.O.

    1983-12-01

    The utility of a semi-automatic method of measuring left ventricular (LV) volume geometrically from gated blood-pool studies and digital subtraction angiography (DSA) was investigated using computerized edge detection and spatial calibration algorithms. LAO LV volumes determined from gated blood-pool studies were compared to volumes obtained from contrast left ventriculograms in 21 patients and the applicability of this method to DSA was evaluated in 25 additional patients who also had conventional left ventriculography. There was excellent correlation between the two, both for radionuclide studies and for DSA. Computer-based geometric determinations of LV volume appear to be rapid, accurate, and less dependent on subjective operator decisions than previously reported geometric approaches.

  6. RISK BASED TESTING A Fuzzy Approach

    Directory of Open Access Journals (Sweden)

    Ochin Sharma

    2011-10-01

    Full Text Available Earlier Testers used to concentrate on only functionality, usability or performance sort of testing. Many of these derived by the customer’s desire or need. Same thing was with the risk based testing. If an application used to be real time based or crucial in terms or national security or economic then it was considered to be a risk based testing candidate. But business of individual has equalimportance for the people. Hence now risked based scenario and testing is a must do strategy. But based on the various factors how will you decide when an event or activity is under risk and should be treated on priority based. In real time projects many activities cannot be decided as ‘Yes’ or ‘No’ criteria. For example in a project if any one person is left out of 10 members’ team. It cannot be treated as crucial, but if 5 members left within short span of time. This 50% breakdown in work force definitely be consider as critical, so here we can wave a red (priority signal. So fuzzy approach can be consider as an important deal with respect of risk management

  7. Solving Operator Equation Based on Expansion Approach

    Directory of Open Access Journals (Sweden)

    A. Aminataei

    2014-01-01

    Full Text Available To date, researchers usually use spectral and pseudospectral methods for only numerical approximation of ordinary and partial differential equations and also based on polynomial basis. But the principal importance of this paper is to develop the expansion approach based on general basis functions (in particular case polynomial basis for solving general operator equations, wherein the particular cases of our development are integral equations, ordinary differential equations, difference equations, partial differential equations, and fractional differential equations. In other words, this paper presents the expansion approach for solving general operator equations in the form Lu+Nu=g(x,x∈Γ, with respect to boundary condition Bu=λ, where L, N and B are linear, nonlinear, and boundary operators, respectively, related to a suitable Hilbert space, Γ is the domain of approximation, λ is an arbitrary constant, and g(x∈L2(Γ is an arbitrary function. Also the other importance of this paper is to introduce the general version of pseudospectral method based on general interpolation problem. Finally some experiments show the accuracy of our development and the error analysis is presented in L2(Γ norm.

  8. Transient cortical blindness after coronary angiography.

    Science.gov (United States)

    Alp, B N; Bozbuğa, N; Tuncer, M A; Yakut, C

    2009-01-01

    Transient cortical blindness is rarely encountered after angiography of native coronary arteries or bypass grafts. This paper reports a case of transient cortical blindness that occurred 72 h after coronary angiography in a 56-year old patient. This was the patient's fourth exposure to contrast medium. Neurological examination demonstrated cortical blindness and the absence of any focal neurological deficit. A non-contrast-enhanced computed tomographic scan of the brain revealed bilateral contrast enhancement in the occipital lobes and no evidence of cerebral haemorrhage, and magnetic resonance imaging of the brain showed no pathology. Sight returned spontaneously within 4 days and his vision gradually improved. A search of the current literature for reported cases of transient cortical blindness suggested that this is a rarely encountered complication of coronary angiography.

  9. Creative teaching an evidence-based approach

    CERN Document Server

    Sale, Dennis

    2015-01-01

    This book contains an evidence-based pedagogic guide to enable any motivated teaching/training professional to be able to teach effectively and creatively. It firstly summarises the extensive research field on human psychological functioning relating to learning and how this can be fully utilised in the design and facilitation of quality learning experiences. It then demonstrates what creativity actually 'looks like' in terms of teaching practices, modelling the underpinning processes of creative learning design and how to apply these in lesson planning. The book, having established an evidence-based and pedagogically driven approach to creative learning design, extensively focuses on key challenges facing teaching professionals today. These include utilising information technologies in blended learning formats, differentiating instruction, and developing self-directed learners who can think well. The main purpose of the book is to demystify what it means to teach creatively, explicitly demonstrating the pr...

  10. Determinants of image quality of rotational angiography for on-line assessment of frame geometry after transcatheter aortic valve implantation

    NARCIS (Netherlands)

    R. Rodríguez-Olivares (Ramón); N. El Faquir (Nahid); Z. Rahhab (Zouhair); A.M. Maugenest; N.M. van Mieghem (Nicolas); C. Schultz (Carl); G. Lauritsch (Guenter); P.P.T. de Jaegere (Peter)

    2016-01-01

    textabstractTo study the determinants of image quality of rotational angiography using dedicated research prototype software for motion compensation without rapid ventricular pacing after the implantation of four commercially available catheter-based valves. Prospective observational study including

  11. Digital subtraction angiography of the thoracic aorta

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, L.B.; Buonocore, E.; Modic, M.T.; Meaney, T.F.

    1984-02-01

    Forty-three patients with acquired and congenital abnormalities of the thoracic aorta were studied using digital subtraction angiography (DSA) after an intravenous bolus injection of 40 ml of contrast material. Abnormalities studied included coarctation, pseudocoarctation, Marfan syndrome, cervical aorta, double aortic arch, aneurysm, dissection, and tumor. Twenty-four patients also had conventional angiography. DSA was accurate in 95% of cases; in the other 5%, involving patients with acute type I dissection, the coronary arteries could not be seen. The authors concluded that in 92% of their patients, DSA could have replaced the standard aortogram.

  12. The Efficacy of Iopamidol (Pamiray 370) in Aortic and Extremity CT Angiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yoo Jin; Lee, Jong Min; Lee, Hui Joong; Park, Ji Won [Kyungpook National University Hospital, Daegu (Korea, Republic of)

    2010-01-15

    To evaluate the clinical safety and radiological feasibility of a domestic iopamidol-based contrast media (Pamiray 370) during an aortic and extremity CT angiography. Between August and December of 2008, 100 patients (M:F=51:49; mean age, 59 years) underwent an aortic and extremity CT angiography using Pamiray 370 based with informed consent. All changes in vital signs, clinical symptoms, and adverse reactions to the contrast media were monitored. Two radiologists assessed the image quality of the CT angiography. A statistical comparison was conducted using an independent t-test and a Mann-Whitney test based on the 100-patient group studied using Optiray 350. The contrast enhancement of the descending aorta in the arterial phase showed a statistically greater efficacy (p<0.001) of Pamiray 370 compared to Optiray 350, which was the routine contrast media for CT angiography for our institute. Adverse reaction signs were evident in 3%(3/100) of the subjects. All of them showed mild and transient reactions such as vomiting (n=2) and coughing (n=1), with no medical treatment required. Contrast media related symptoms including dizziness (n=7), nausea (n=3), headaches (n=2), and injection site pain (n=1), were noted in 12%(12/100). The clinical efficacy of Pamiray 370 was acceptable for the aortic and extremity CT angiography, in terms of clinical safety, tolerance, and image quality.

  13. CT angiography and CT perfusion in acute ischemic stroke

    NARCIS (Netherlands)

    Seeters, T. van

    2016-01-01

    CT angiography and CT perfusion are used in patients with acute ischemic stroke for diagnostic purposes and to select patients for treatment. In this thesis, the reproducibility of CT angiography and CT perfusion is examined, the additional value of CT angiography and CT perfusion for stroke outcome

  14. Diagnostic accuracy of 64 multislice CT angiography in the assessment of coronary in-stent restenosis: A meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sun Zhonghua [Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University of Technology, Perth, WA (Australia)], E-mail: z.sun@curtin.edu.au; Almutairi, Abdulrahman Marzouq D. [Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University of Technology, Perth, WA (Australia)

    2010-02-15

    Purpose: The aim of this study was to perform a meta-analysis of the diagnostic accuracy of 64-slice CT angiography for the detection of coronary in-stent restenosis in patients treated with coronary stents when compared to conventional coronary angiography. Materials and methods: A search of PUBMED/MEDLINE, ProQuest and Cochrane library databases for English literature was performed. Only studies comparing 64-slice CT angiography with conventional coronary angiography for the detection of coronary in-stent restenosis (more than 50% stenosis) were included for analysis. Sensitivity and specificity estimates pooled across studies were tested using a fixed effects model. Results: Fourteen studies met selection criteria for inclusion in the analysis. The mean value of assessable stents was 89%. Prevalence of in-stent restenosis following coronary stenting was 20% among these studies. Pooled estimates of the sensitivity and specificity of overall 64-slice CT angiography for the detection of coronary in-stent restenosis was 90% (95% CI: 86%, 94%) and 91% (95% CI: 90%, 93%), respectively, based on the evaluation of assessable stents. Diagnostic value of 64-slice CT angiography was found to decrease significantly when the analysis was performed with inclusion of nonassessable segments in five studies, with pooled sensitivity and specificity being 79% (95% CI: 68%, 88%) and 81% (95% CI: 77%, 84%). Stent diameter is the main factor affecting the diagnostic value of 64-slice CT angiography. Conclusion: Our results showed that 64-slice CT angiography has high diagnostic value (both sensitivity and specificity) for detection of coronary in-stent restenosis based on assessable segments when compared to conventional coronary angiography.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  16. CRosser As First choice for crossing Totally occluded coronary arteries (CRAFT Registry): Focus on conventional angiography and computed tomography angiography predictors of success

    NARCIS (Netherlands)

    H.M. Garcia-Garcia (Hector); S. Brugaletta (Salvatore); C.A.G. van Mieghem (Carlos); N. Gonzalo (Nieves); R. Diletti (Roberto); J. Gomez-Lara (Josep); F. Airoldi (Flavio); M. Carlino (Mauro); D. Tavano (Davide); A. Chieffo (Alaide); M. Montorfano (Matteo); I. Michev (Iassen); A. Colombo (Antonio); M. van der Ent (Martin); P.W.J.C. Serruys (Patrick)

    2011-01-01

    textabstractAims: We investigated the use of the CROSSER catheter, a CTO crossing device based upon high frequency mechanical vibration, as a first resort to treat patients with chronic total occlusions (CTO) while describing angiographic and computed tomography coronary angiography (CTCA) serving a

  17. Peptide Based Radiopharmaceuticals: Specific Construct Approach

    Energy Technology Data Exchange (ETDEWEB)

    Som, P; Rhodes, B A; Sharma, S S

    1997-10-21

    The objective of this project was to develop receptor based peptides for diagnostic imaging and therapy. A series of peptides related to cell adhesion molecules (CAM) and immune regulation were designed for radiolabeling with 99mTc and evaluated in animal models as potential diagnostic imaging agents for various disease conditions such as thrombus (clot), acute kidney failure, and inflection/inflammation imaging. The peptides for this project were designed by the industrial partner, Palatin Technologies, (formerly Rhomed, Inc.) using various peptide design approaches including a newly developed rational computer assisted drug design (CADD) approach termed MIDAS (Metal ion Induced Distinctive Array of Structures). In this approach, the biological function domain and the 99mTc complexing domain are fused together so that structurally these domains are indistinguishable. This approach allows construction of conformationally rigid metallo-peptide molecules (similar to cyclic peptides) that are metabolically stable in-vivo. All the newly designed peptides were screened in various in vitro receptor binding and functional assays to identify a lead compound. The lead compounds were formulated in a one-step 99mTc labeling kit form which were studied by BNL for detailed in-vivo imaging using various animals models of human disease. Two main peptides usingMIDAS approach evolved and were investigated: RGD peptide for acute renal failure and an immunomodulatory peptide derived from tuftsin (RMT-1) for infection/inflammation imaging. Various RGD based metallopeptides were designed, synthesized and assayed for their efficacy in inhibiting ADP-induced human platelet aggregation. Most of these peptides displayed biological activity in the 1-100 µM range. Based on previous work by others, RGD-I and RGD-II were evaluated in animal models of acute renal failure. These earlier studies showed that after acute ischemic injury the renal cortex displays

  18. Spinal angiography: vascular anatomy, technique, indications; Spinale Angiographie: Gefaessanatomie, Technik und Indikationsstellung

    Energy Technology Data Exchange (ETDEWEB)

    Grunwald, I.; Reith, W. [Universitaet des Saarlandes, Homburg/Saar (Germany). Abt. fuer Neuroradiologie; Thron, A. [Universitaetsklinik der RWTH Aachen (Germany). Abteilung fuer Neuroradiologie

    2001-11-01

    The indication for spinal angiography has to be closely set as in case of inadequate handling this procedure bares the risk of paraplegia. In unclear spinal symptoms lasting over a longer periode of time, spinal vascular malformation have to be considered. Spinal vascular malformations are often reversibel, especially if diagnosed early. Diagnostic methods have to include spinal angiography if other non-invasive methods do not lead to results. The main point is to consider spinal vascular malformations in unclear cases. (orig.) [German] Die Indikation zu einer spinalen Angiographie muss streng gestellt werden, da bei unsachgemaesser Durchfuehrung dieser Untersuchung die Gefahr einer bleibenden Querschnittsymptomatik besteht. Bei unklarer spinaler Symptomatik, die ueber einen laengeren Zeitraum progredient ist, muss jedoch immer auch an eine spinale Gefaessfehlbildung gedacht werden. Die durch alle diagnostischen Moeglichkeiten einschliesslich der spinalen Angiographie diagnostizierten spinalen Gefaessfehlbildungen sind haeufig kurabel, insbesondere bei frueher Diagnosestellung. Der wichtigste Punkt ist jedoch, dass differenzialdiagnostisch auch an eine spinale Gefaessfehlbildung gedacht wird. (orig.)

  19. New approaches in diffraction based optical metrology

    Science.gov (United States)

    Ebert, M.; Vanoppen, P.; Jak, M.; v. d. Zouw, G.; Cramer, H.; Nooitgedagt, T.; v. d. Laan, H.

    2016-03-01

    Requirements for on-product overlay, focus and CD uniformity continue to tighten in order to support the demands of 10nm and 7nm nodes. This results in the need for simultaneously accurate, robust and dense metrology data as input for closed-loop control solutions thereby enabling wafer-level control and high order corrections. In addition the use of opaque materials and stringent design rules drive the need for expansion of the available measurement wavelengths and metrology target design space. Diffraction based optical metrology has been established as the leading methodology for integrated as well as standalone optical metrology for overlay, focus and CD monitoring and control in state of the art chip manufacturing. We are presenting the new approaches to diffraction based optical metrology designed to meet the processing diffraction based metrology signals. In this paper we will present the new detection principle and its impact on key performance characteristics of overlay and focus measurements. We will also describe the wide range of applications of a newly introduced increased measurement spot size, enabling significant improvements to accuracy and process robustness of overlay and focus measurements. With the YS350E the optical CD measurement capability is also extended, to 10x10μm2 targets. We will discuss the performance and value of small targets in after-develop and after-etch applications.

  20. Toxidrome-based Approach to Common Poisonings

    Directory of Open Access Journals (Sweden)

    Bruno Mégarbane

    2014-03-01

    Full Text Available Poisoning remains a major cause of hospital admission into the emergency department and intensive care unit. Proper diagnosis is the cornerstone for optimal management of poisoned patients. Since the definitive analytical confirmation of the nature of the toxicant involved in the poisoning cannot be rapidly obtained in the majority of healthcare facilities, diagnosis relies on the medical history and the rigorous clinical examination of the patients well as results of the routine biological tests and the electrocardiogram. Identification of the toxidromes addresses not only the correct diagnosis but also rules out other differential diagnoses. Despite no definitive predictive value, this clinical approach facilitates making decision on empirical treatments and emergent antidotes. Pharmacodynamic tests using specific antidotes including naloxone for opioids and flumazenil for benzodiazepines and its analogues are also helpful to assess the final diagnosis in comatose patients. The objective of this article is to review the toxidrome-based approach to common poisonings before toxicological analysis enables the confirmation of the initially suspected toxic etiology.

  1. Age Classification Based On Integrated Approach

    Directory of Open Access Journals (Sweden)

    Pullela. SVVSR Kumar

    2014-05-01

    Full Text Available The present paper presents a new age classification method by integrating the features derived from Grey Level Co-occurrence Matrix (GLCM with a new structural approach derived from four distinct LBP's (4-DLBP on a 3 x 3 image. The present paper derived four distinct patterns called Left Diagonal (LD, Right diagonal (RD, vertical centre (VC and horizontal centre (HC LBP's. For all the LBP's the central pixel value of the 3 x 3 neighbourhood is significant. That is the reason in the present research LBP values are evaluated by comparing all 9 pixels of the 3 x 3 neighbourhood with the average value of the neighbourhood. The four distinct LBP's are grouped into two distinct LBP's. Based on these two distinct LBP's GLCM is computed and features are evaluated to classify the human age into four age groups i.e: Child (0-15, Young adult (16-30, Middle aged adult (31-50 and senior adult (>50. The co-occurrence features extracted from the 4-DLBP provides complete texture information about an image which is useful for classification. The proposed 4-DLBP reduces the size of the LBP from 6561 to 79 in the case of original texture spectrum and 2020 to 79 in the case of Fuzzy Texture approach.

  2. Nanotechnology-based approaches in anticancer research.

    Science.gov (United States)

    Jabir, Nasimudeen R; Tabrez, Shams; Ashraf, Ghulam Md; Shakil, Shazi; Damanhouri, Ghazi A; Kamal, Mohammad A

    2012-01-01

    Cancer is a highly complex disease to understand, because it entails multiple cellular physiological systems. The most common cancer treatments are restricted to chemotherapy, radiation and surgery. Moreover, the early recognition and treatment of cancer remains a technological bottleneck. There is an urgent need to develop new and innovative technologies that could help to delineate tumor margins, identify residual tumor cells and micrometastases, and determine whether a tumor has been completely removed or not. Nanotechnology has witnessed significant progress in the past few decades, and its effect is widespread nowadays in every field. Nanoparticles can be modified in numerous ways to prolong circulation, enhance drug localization, increase drug efficacy, and potentially decrease chances of multidrug resistance by the use of nanotechnology. Recently, research in the field of cancer nanotechnology has made remarkable advances. The present review summarizes the application of various nanotechnology-based approaches towards the diagnostics and therapeutics of cancer.

  3. Wavelet based approach for facial expression recognition

    Directory of Open Access Journals (Sweden)

    Zaenal Abidin

    2015-03-01

    Full Text Available Facial expression recognition is one of the most active fields of research. Many facial expression recognition methods have been developed and implemented. Neural networks (NNs have capability to undertake such pattern recognition tasks. The key factor of the use of NN is based on its characteristics. It is capable in conducting learning and generalizing, non-linear mapping, and parallel computation. Backpropagation neural networks (BPNNs are the approach methods that mostly used. In this study, BPNNs were used as classifier to categorize facial expression images into seven-class of expressions which are anger, disgust, fear, happiness, sadness, neutral and surprise. For the purpose of feature extraction tasks, three discrete wavelet transforms were used to decompose images, namely Haar wavelet, Daubechies (4 wavelet and Coiflet (1 wavelet. To analyze the proposed method, a facial expression recognition system was built. The proposed method was tested on static images from JAFFE database.

  4. Linear systems a measurement based approach

    CERN Document Server

    Bhattacharyya, S P; Mohsenizadeh, D N

    2014-01-01

    This brief presents recent results obtained on the analysis, synthesis and design of systems described by linear equations. It is well known that linear equations arise in most branches of science and engineering as well as social, biological and economic systems. The novelty of this approach is that no models of the system are assumed to be available, nor are they required. Instead, a few measurements made on the system can be processed strategically to directly extract design values that meet specifications without constructing a model of the system, implicitly or explicitly. These new concepts are illustrated by applying them to linear DC and AC circuits, mechanical, civil and hydraulic systems, signal flow block diagrams and control systems. These applications are preliminary and suggest many open problems. The results presented in this brief are the latest effort in this direction and the authors hope these will lead to attractive alternatives to model-based design of engineering and other systems.

  5. Sepsis management: An evidence-based approach.

    Science.gov (United States)

    Baig, Muhammad Akbar; Shahzad, Hira; Jamil, Bushra; Hussain, Erfan

    2016-03-01

    The Surviving Sepsis Campaign (SSC) guidelines have outlined an early goal directed therapy (EGDT) which demonstrates a standardized approach to ensure prompt and effective management of sepsis. Having said that, there are barriers associated with the application of evidence-based practice, which often lead to an overall poorer adherence to guidelines. Considering the global burden of disease, data from low- to middle-income countries is scarce. Asia is the largest continent but most Asian countries do not have a well-developed healthcare system and compliance rates to resuscitation and management bundles are as low as 7.6% and 3.5%, respectively. Intensive care units are not adequately equipped and financial concerns limit implementation of expensive treatment strategies. Healthcare policy-makers should be notified in order to alleviate financial restrictions and ensure delivery of standard care to septic patients.

  6. Post-mortem CT-coronary angiography

    DEFF Research Database (Denmark)

    Pøhlsgaard, Camilla; Leth, Peter Mygind

    2007-01-01

    post-mortem coronary angiography and computerized tomography.  We describe how to prepare and inject the contrast medium, and how to establish a CT-protocol that optimizes spatial resolution, low contrast resolution and noise level. Testing of the method on 6 hearts, showed that the lumen...

  7. Spinal angiography. Anatomy, technique and indications; Spinale Angiographie. Anatomie, Technik und Indikation

    Energy Technology Data Exchange (ETDEWEB)

    Reith, W.; Simgen, A.; Yilmaz, U. [Universitaetsklinikum des Saarlandes, Klinik fuer Diagnostische und Interventionelle Neuroradiologie, Homburg/Saar (Germany)

    2012-05-15

    Spinal angiography is a diagnostic modality requiring detailed knowledge of spinal vascular anatomy. The cervical spinal cord is supplied by the vertebral arteries while segmental arteries which are preserved from fetal anatomy, supply the thoracic and lumbar regions. As spinal angiography carries the risk of paraplegia the indications have to be considered very carefully. Nevertheless, spinal angiography should be performed if there is reason to suspect a spinal vascular malformation from magnetic resonance imaging (MRI). (orig.) [German] Indikationsstellung, Technik und Durchfuehrung der spinalen Angiographie erfordern detaillierte Kenntnisse der Gefaessversorgung des Spinalkanals und des Rueckenmarks. Die Gefaessversorgung des Rueckenmarks erfolgt im Bereich des Halsmarks aus den beiden Aa. vertebrales. Eine zusaetzliche arterielle Versorgung der Wirbelsaeule einschliesslich des Rueckenmarks wird ueber segmentale Arterien hergestellt, die im Bereich der Thorakal- und Lumbalregion aus der Embryonalphase als segmentale, interkostale und Lumbalarterien erhalten geblieben sind. Da die spinale Angiographie die Gefahr der Querschnittslaehmung birgt, ist eine strenge Indikation notwendig. Eine ueber laengere Zeit bestehende unklare klinische Symptomatik kann auch durch eine spinale Gefaessmalformation hervorgerufen werden. Ist durch die MRT-Bildgebung der Verdacht auf eine spinale Gefaessfehlbildung gegeben, sollte eine Angiographie durchgefuehrt werden, da diese Fehlbildungen oft kurabel sind. (orig.)

  8. A Rule-Based Approach To Prepositional Phrase Attachment Disambiguation

    CERN Document Server

    Brill, E; Brill, Eric; Resnik, Philip

    1994-01-01

    In this paper, we describe a new corpus-based approach to prepositional phrase attachment disambiguation, and present results comparing performance of this algorithm with other corpus-based approaches to this problem.

  9. Coronary CT angiography in coronary artery disease: Opportunities and challenges

    Directory of Open Access Journals (Sweden)

    Zhonghua Sun

    2016-06-01

    Full Text Available Coronary CT angiography is widely recognised as a reliable imaging modality for the diagnosis of coronary artery disease. Coronary CT angiography not only provides excellent visualisation of anatomical changes in the coronary artery with high diagnostic value in the detection of lumen stenosis or occlusion, but also offers quantitative characterisation of coronary plaque components. Furthermore, coronary CT angiography allows myocardial perfusion imaging with diagnostic value comparable to the reference standard method. Coronary CT angiography-derived haemodynamic analysis has the potential to evaluate functional significance of coronary lesions. This review article aims to provide an overview of clinical applications of coronary CT angiography in coronary artery disease.

  10. Prevalence of Unruptured Intracranial Aneurysm on MR Angiography

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Tae Yeon; Jeon, Pyoung; Kim, Keon Ha [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2011-10-15

    To evaluate the prevalence of incidentally found unruptured intracranial aneurysms (UIAs) on the brain MR angiography (MRA) from a community-based general hospital. This was a prospectively collected retrospective study, carried out from January 2004 to December 2004. The subjects included 3049 persons from a community-based hospital in whom MRA was performed according to a standardized protocol in an outpatient setting. Age- and sex-specific prevalence of UIAs was calculated. The results by MRA were compared with intra-arterial digital subtraction angiography (DSA) findings. Unruptured intracranial aneurysms were found in 137 (5%) of the 3049 patients (M:F 43:94; mean age, 60.2 years). The prevalence of UIAs was 5% (n = 94) in women and 4% (n = 43) in men, respectively (p = 0.2046) and showed no age-related increase. The most common site of aneurysm was at the distal internal carotid artery (n = 64, 39%), followed by the middle cerebral artery (n = 40, 24%). In total, 99% of aneurysms measured less than 12 mm, and 93% of aneurysms measured less than 7 mm. Direct comparisons between MRA and DSA were available in 70 patients with 83 UIAs; the results revealed two false positive and two false negative results. This community-hospital based study suggested a higher prevalence of UIAs observed by MRA than previously reported. These findings should be anticipated in the design and use of neuroimaging in clinical practice.

  11. [CT coronary angiography: indications, image acquisition, and interpretation].

    Science.gov (United States)

    Schoepf, U J; Thilo, C; Fernández, M J; Costello, P

    2008-01-01

    Intense scientific and clinical evaluation have brought about great improvements in cardiac CT. This is no longer merely an experimental technique, rather it has become a clinical application that is ready to fulfill its promise of replacing invasive cardiac catheterization in certain patient populations. Among the proven indications is the evaluation of patients with atypical chest pain, the morphological evaluation of the coronary arteries in cases of suspected congenital anomalies, and before surgical intervention, as well as the evaluation of coronary revascularizations. The use of CT angiography for the exhaustive evaluation of cardiac and non-cardiac pathology in patients with acute chest pain in the emergency department is currently being investigated. Because the heart is continuously moving, CT coronary angiography represents a greater technical challenge than other applications of CT. On the other hand, rapid technical development requires acquisition protocols to be adjusted constantly. However, users that know the general techniques of computed tomography can overcome these challenges. The aim of this article is to provide those interested and involved in CT angiography with a manual to enable them to follow our method step by step. We include considerations regarding the correct selection of patients, patient medication, radiological protection, contrast enhancement, acquisition and reconstruction parameters, image display, image analysis techniques, and the radiological report. Our recommendations are based on our experience, which runs from the evolution of multiple-row detector CT scanners for cardiac applications from its beginnings to the most modern presentations of advanced acquisition modalities, including dual-source CT, which we consider to be the precursor of this test in routine clinical practice.

  12. Coarctation of the aorta: comparison of aortic dimensions between conventional MR imaging, 3D MR angiography, and conventional angiography

    Energy Technology Data Exchange (ETDEWEB)

    Godart, Francois; Rey, Christian [Department of Paediatric Cardiology, Cardiac Hospital, University of Lille, 59037 Lille (France); Labrot, Gabrielle; McFadden, Eugene; Beregi, Jean-Paul [Department of Radiology, Cardiac Hospital, University of Lille, 59037 Lille (France); Devos, Patrick [CERIM-Department of Biostatistics, University of Lille, 59037 Lille (France)

    2002-08-01

    Magnetic resonance angiography is increasingly used as a non-invasive method in the evaluation of coarctation of the aorta. The aim of this study was to compare aortic dimensions calculated by MR angiography and those obtained by more conventional MR sequences and conventional angiography. Twenty-six consecutive patients with coarctation underwent three-dimensional MR angiography. Two independent observers retrospectively evaluated three aortic segments, site of coarctation, presence of aneurysm and existence of collateral circulation. Three aortic segments were also compared with those obtained on classical MR sequences and conventional angiography. The MR angiography was successfully performed in all showing 1 aneurysm and collateral circulation in 8 patients. Almost perfect intraobserver (r{sup 2}>0.91) and excellent interobserver (r{sup 2}>0.80) reliabilities were obtained for each aortic segment no matter which MR sequence was employed. Similarly, mainly excellent (r{sup 2}>0.80) concordance analysis was observed between MR angiography measurements and those calculated by either spin-echo/gradient-echo sequences or conventional angiography. This study demonstrates that MR angiography is a fast, accurate and reproducible method in the evaluation of coarctation of the aorta. It provides excellent anatomic information and reliably detects collateral vessels. Magnetic resonance angiography could probably replace the conventional angiography and will provide an additional diagnostic value in combination with turbo spin-echo sequence. (orig.)

  13. [Patients with hemodynamic unstable pelvic fractures in extremis: pelvic packing or angiography?].

    Science.gov (United States)

    Liñán-Padilla, A; Giráldez-Sánchez, M Á; Serrano-Toledano, D; Lázaro-Gonzálvez, A; Cano-Luís, P

    2013-01-01

    The multidisciplinary management of patients with pelvic trauma has improved prognosis, but mortality is still very high. The appropriate treatment strategy remains controversial, especially regarding the control of bleeding in patients whose clinical situation is extreme by using angiography or pelvic packing. We propose using a tool of evidence-based medicine (CAT) the benefit of the completion of pelvic packing in relation to a specific clinical question from a specific situation. What is best for the management of bleeding, extraperitoneal pelvic packing or angiography, in patients with hemodynamically unstable pelvic fracture in extremis? From this study we can conclude that angiography may improve control of bleeding in patients with arterial bleeding and hemodynamically stable but the packing has priority in patients with pelvic fractures and hemodynamic instability.

  14. Evaluation of spinal cord vessels using multi-slice CT angiography

    Institute of Scientific and Technical Information of China (English)

    陈爽; 钱建国; 冯晓源

    2004-01-01

    @@ Compared with the large number of head and neck vascular studies, computer tomography (CT) angiography of spinal vascular lesions has received relatively little attention. Several series and a few isolated cases of spinal vascular malformations demonstrated with magnetic resonance (MR) angiography have been reported.1-3 Selective digital subtraction angiography (DSA) is gold standard for diagnosis of spinal vascular lesions.4 However, it is invasive, time consuming, expensive, and dependent on the skills of the operator. Based on the DSA appearance and the surgical findings, spinal vascular malformations are generally, although not universally, classified as intradural (intramedullary and/or extramedullary) arteriovenous malformation (AVM) or arteriovenous fistula (AVF), and dural AVF. Recommended treatments of dural AVF consist of surgical obliteration and/or embolization.5-8

  15. Wide-Field OCT Angiography at 400 KHz Utilizing Spectral Splitting

    Directory of Open Access Journals (Sweden)

    Laurin Ginner

    2014-10-01

    Full Text Available Optical angiography systems based on optical coherence tomography (OCT require dense sampling in order to maintain good vascular contrast. We demonstrate a way to gain acquisition speed and spatial sampling by using spectral splitting with a swept source OCT system. This method splits the recorded spectra into two to several subspectra. Using continuous lateral scanning, the lateral sampling is then increased by the same factor. This allows increasing the field of view of OCT angiography, while keeping the same transverse resolution and measurement time. The performance of our method is demonstrated in vivo at different locations of the human retina and verified quantitatively. Spectral splitting can be applied without any changes in the optical setup, thus offering an easy way to increase the field of view of OCT in general and in particular for OCT angiography.

  16. Filtered region of interest cone-beam rotational angiography

    Energy Technology Data Exchange (ETDEWEB)

    Schafer, Sebastian; Noeel, Peter B.; Walczak, Alan M.; Hoffmann, Kenneth R. [Department of Mechanical Engineering, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Neurosurgery, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States) and Toshiba Stroke Research Center, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Neurosurgery, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Computer Science, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States) and Toshiba Stroke Research Center, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Neurosurgery, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 and Toshiba Stroke Research Center, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Mechanical Engineering, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Neurosurgery, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Computer Science, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States) and Toshiba Stroke Research Center, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States)

    2010-02-15

    Purpose: Cone-beam rotational angiography (CBRA) is widely used in the modern clinical settings. In a number of procedures, the area of interest is often considerably smaller than the field of view (FOV) of the detector, subjecting the patient to potentially unnecessary x-ray dose. The authors therefore propose a filter-based method to reduce the dose in the regions of low interest, while supplying high image quality in the region of interest (ROI). Methods: For such procedures, the authors propose a method of filtered region of interest (FROI)-CBRA. In the authors' approach, a gadolinium filter with a circular central opening is placed into the x-ray beam during image acquisition. The central region is imaged with high contrast, while peripheral regions are subjected to a substantial lower intensity and dose through beam filtering. The resulting images contain a high contrast/intensity ROI, as well as a low contrast/intensity peripheral region, and a transition region in between. To equalize the two regions' intensities, the first projection of the acquisition is performed with and without the filter in place. The equalization relationship, based on Beer's law, is established through linear regression using corresponding filtered and nonfiltered data. The transition region is equalized based on radial profiles. Results: Evaluations in 2D and 3D show no visible difference between conventional FROI-CBRA projection images and reconstructions in the ROI. CNR evaluations show similar image quality in the ROI, with a reduced CNR in the reconstructed peripheral region. In all filtered projection images, the scatter fraction inside the ROI was reduced. Theoretical and experimental dose evaluations show a considerable dose reduction; using a ROI half the original FOV reduces the dose by 60% for the filter thickness of 1.29 mm. Conclusions: These results indicate the potential of FROI-CBRA to reduce the dose to the patient while supplying the physician with

  17. Concurrency-based approaches to parallel programming

    Science.gov (United States)

    Kale, L.V.; Chrisochoides, N.; Kohl, J.; Yelick, K.

    1995-01-01

    The inevitable transition to parallel programming can be facilitated by appropriate tools, including languages and libraries. After describing the needs of applications developers, this paper presents three specific approaches aimed at development of efficient and reusable parallel software for irregular and dynamic-structured problems. A salient feature of all three approaches in their exploitation of concurrency within a processor. Benefits of individual approaches such as these can be leveraged by an interoperability environment which permits modules written using different approaches to co-exist in single applications.

  18. Types of diaphragmatic motion during hepatic angiography.

    Science.gov (United States)

    Katsuda, T; Kuroda, C; Fujita, M

    1997-01-01

    To determine the types and causes of diaphragmatic motion during hepatic angiography, the authors used transarterial cut-film portography (TAP) to study movement of the diaphragm during breath-holding. Thirty-three TAP sequences were studied, and the patients' diaphragmatic motions were classified into four categories according to the distance their diaphragms moved. Results showed that the diaphragm was stationary in 33% of the TAP studies, while perpetual motion occurred in 15% of the studies, early-phase motion occurred in 12% and late-phase motion occurred in 40%. Ten sequences showed diaphragmatic motion of more than 10 mm, with eight sequences showing caudal motion and two showing cranial motion. This article discusses the cause of diaphragmatic motion during breath-holding for hepatic angiography and presents suggestions to reduce motion artifacts during the exam.

  19. IPTV inter-destination synchronization: A network-based approach

    NARCIS (Netherlands)

    Stokking, H.M.; Deventer, M.O. van; Niamut, O.A.; Walraven, F.A.; Mekuria, R.N.

    2010-01-01

    This paper introduces a novel network-based approach to inter-destination media synchronization. The approach meets the need for synchronization in advanced TV concepts like social TV and offers high scalability, unlike conventional end-point based approaches. The solution for interdestination media

  20. Cardiac CT Angiography in Congestive Heart Failure.

    Science.gov (United States)

    Levine, Avi; Hecht, Harvey S

    2015-06-01

    Cardiac CT angiography has become an important tool for the diagnosis and treatment of congestive heart failure. Differentiation of ischemic from nonischemic cardiomyopathy; evaluation of myocardial perfusion; characterization of hypertrophic cardiomyopathy, left ventricular noncompaction, and arrhythmogenic right ventricular dysplasia; and delineation of congenital heart defects and valvular abnormalities are the primary diagnostic applications. Therapeutic use includes visualization of the coronary venous anatomy for optimal implementation of cardiac resynchronization therapy and evaluation of left ventricular assist devices and transplant vasculopathy.

  1. Optical Coherence Tomography Angiography in Retinal Diseases.

    Science.gov (United States)

    Chalam, K V; Sambhav, Kumar

    2016-01-01

    Optical coherence tomography angiography (OCTA) is a new, non-invasive imaging system that generates volumetric data of retinal and choroidal layers. It has the ability to show both structural and blood flow information. Split-spectrum amplitude-decorrelation angiography (SSADA) algorithm (a vital component of OCTA software) helps to decrease the signal to noise ratio of flow detection thus enhancing visualization of retinal vasculature using motion contrast. Published studies describe potential efficacy for OCTA in the evaluation of common ophthalmologic diseases such as diabetic retinopathy, age related macular degeneration (AMD), retinal vascular occlusions and sickle cell disease. OCTA provides a detailed view of the retinal vasculature, which allows accurate delineation of microvascular abnormalities in diabetic eyes and vascular occlusions. It helps quantify vascular compromise depending upon the severity of diabetic retinopathy. OCTA can also elucidate the presence of choroidal neovascularization (CNV) in wet AMD. In this paper, we review the knowledge, available in English language publications regarding OCTA, and compare it with the conventional angiographic standard, fluorescein angiography (FA). Finally, we summarize its potential applications to retinal vascular diseases. Its current limitations include a relatively small field of view, inability to show leakage, and tendency for image artifacts. Further larger studies will define OCTA's utility in clinical settings and establish if the technology may offer a non-invasive option of visualizing the retinal vasculature, enabling us to decrease morbidity through early detection and intervention in retinal diseases.

  2. Optical coherence tomography angiography in retinal diseases

    Directory of Open Access Journals (Sweden)

    K V Chalam

    2016-01-01

    Full Text Available Optical coherence tomography angiography (OCTA is a new, non-invasive imaging system that generates volumetric data of retinal and choroidal layers. It has the ability to show both structural and blood flow information. Split-spectrum amplitude-decorrelation angiography (SSADA algorithm (a vital component of OCTA software helps to decrease the signal to noise ratio of flow detection thus enhancing visualization of retinal vasculature using motion contrast. Published studies describe potential efficacy for OCTA in the evaluation of common ophthalmologic diseases such as diabetic retinopathy, age related macular degeneration (AMD, retinal vascular occlusions and sickle cell disease. OCTA provides a detailed view of the retinal vasculature, which allows accurate delineation of microvascular abnormalities in diabetic eyes and vascular occlusions. It helps quantify vascular compromise depending upon the severity of diabetic retinopathy. OCTA can also elucidate the presence of choroidal neovascularization (CNV in wet AMD. In this paper, we review the knowledge, available in English language publications regarding OCTA, and compare it with the conventional angiographic standard, fluorescein angiography (FA. Finally, we summarize its potential applications to retinal vascular diseases. Its current limitations include a relatively small field of view, inability to show leakage, and tendency for image artifacts. Further larger studies will define OCTA's utility in clinical settings and establish if the technology may offer a non-invasive option of visualizing the retinal vasculature, enabling us to decrease morbidity through early detection and intervention in retinal diseases.

  3. Dynamic cone beam CT angiography of carotid and cerebral arteries using canine model

    OpenAIRE

    Cai, Weixing; zhao,binghui; Conover, David; Liu, Jiangkun; Ning, Ruola

    2012-01-01

    Purpose: This research is designed to develop and evaluate a flat-panel detector-based dynamic cone beam CT system for dynamic angiography imaging, which is able to provide both dynamic functional information and dynamic anatomic information from one multirevolution cone beam CT scan.

  4. A discourse based approach in text-based machine translation

    CERN Document Server

    Ullah, Sana; Kwak, Kyung Sup

    2009-01-01

    This paper presents a theoretical research based approach to ellipsis resolution in machine translation. Moreover, the formula of discourse is applied in order to resolve ellipses. The validity of the discourse formula is analyzed by applying it to the real world text i.e. newspaper fragments. The source text is converted into mono-sentential discourses where complex discourses require further dissection either directly into primitive discourses or first into compound discourses and later into primitive ones. The procedure of dissection needs further improvement i.e. discovering as many primitive discourse forms as possible [1]. This work is further improvement to the concepts presented by Khan (Khan, 1995). Likewise, an attempt has been made to investigate new primitive discourses i.e. patterns from the given text.

  5. Dynamic CT head phantom for perfusion and angiography studies

    Science.gov (United States)

    Russell, K.; Blazeski, A.; Dannecker, K.; Lee, Q. Y.; Holscher, C.; Donahue, C.; van Kampen, W.

    2010-03-01

    Contrast imaging is a compelling enhancement for the portable, flat panel-based brain CT scanner currently under development at Xoran. Due to the relative low temporal resolution of flat panel detectors, enabling tomographic imaging on such platform requires optimizing the imaging and injection protocols. A dynamic CT head phantom was designed to facilitate this task. The Dynamic Perfusion and Angiography Model (PAM), mimics tissue attenuation in CT images, provides physiological timing for angiography and perfusion studies, and moves fluid with properties similar to those of blood. The design consists of an arterial system, which contains bifurcating vessels that feed into perfusion chambers, mimicking blood flow through capillaries and smaller vessels, and a venous system, which is symmetrical to the arterial side and drains the perfusion chambers. The variation of geometry and flow rate in the phantom provides the physiological total time that fluid spends in the head, and the difference in material densities correlates to CT numbers for biological tissues. This paper discusses the design of Dynamic PAM and shows experimental results demonstrating its ability to realistically simulate blood flow. Results of dynamic imaging studies of the phantom are also presented.

  6. A Constructivist Approach to Rule Bases

    NARCIS (Netherlands)

    Sileno, G.; Boer, A.; van Engers, T.; Loiseau, S.; Filipe, J.; Duval, B.; van den Herik, J.

    2015-01-01

    The paper presents a set of algorithms for the conversion of rule bases between priority-based and constraint-based representations. Inspired by research in precedential reasoning in law, such algorithms can be used for the analysis of a rule base, and for the study of the impact of the introduction

  7. Image Analysis in CT Angiography

    NARCIS (Netherlands)

    Manniesing, R.

    2006-01-01

    In this thesis we develop and validate novel image processing techniques for the analysis of vascular structures in medical images. First a new type of filter is proposed which is capable of enhancing vascular structures while suppressing noise in the remainder of the image. This filter is based on

  8. Dose reduction with adaptive bolus chasing computed tomography angiography.

    Science.gov (United States)

    Cai, Zhijun; Bai, Er-Wei; Wang, Ge; Sharafuddin, Melhem J; Abada, Hicham T

    2010-01-01

    Computed Tomography (CT) has become an effective diagnosis and evaluating tool in clinical; however, its radiation exposure has drawn great attention as more and more CT scans are performed every year. How to reduce the radiation dose and meanwhile keep the resultant CT images diagnosable becomes an important research topic. In this paper, we propose a dose reduction approach along with the adaptive bolus chasing CT Angiography (CTA) techniques, which are capable of tracking the contrast bolus peak over all the blood vessel segments during the CTA scan. By modulating the tube current (and collimator width) online, we can reduce the total radiation dose and maintain the contrast to noise ratio (CNR) of the blood vessel. Numerical experiments on reference DSA data sets show that by using the proposed dose reduction method, the effective radiation dose can be saved about 39%.

  9. Patient satisfaction with coronary CT angiography, myocardial CT perfusion, myocardial perfusion MRI, SPECT myocardial perfusion imaging and conventional coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Feger, S.; Rief, M.; Zimmermann, E.; Richter, F.; Roehle, R. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Dewey, M. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Institut fuer Radiologie, Berlin (Germany); Schoenenberger, E. [Medizinische Hochschule Hannover, Department of Medicine, Hannover (Germany)

    2015-07-15

    To evaluate patient acceptance of noninvasive imaging tests for detection of coronary artery disease (CAD), including single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), stress perfusion magnetic resonance imaging (MRI), coronary CT angiography (CTA) in combination with CT myocardial stress perfusion (CTP), and conventional coronary angiography (CCA). Intraindividual comparison of perception of 48 patients from the CORE320 multicentre multinational study who underwent rest and stress SPECT-MPI with a technetium-based tracer, combined CTA and CTP (both with contrast agent, CTP with adenosine), MRI, and CCA. The analysis was performed by using a validated questionnaire. Patients had significantly more concern prior to CCA than before CTA/CTP (p < 0.001). CTA/CTP was also rated as more comfortable than SPECT-MPI (p = 0.001). Overall satisfaction with CT was superior to that of MRI (p = 0.007). More patients preferred CT (46 %; p < 0.001) as a future diagnostic test. Regarding combined CTA/CTP, CTP was characterised by higher pain levels and an increased frequency of angina pectoris during the examination (p < 0.001). Subgroup analysis showed a higher degree of pain during SPECT-MPI with adenosine stress compared to physical exercise (p = 0.016). All noninvasive cardiac imaging tests are well accepted by patients, with CT being the preferred examination. (orig.)

  10. Model Mapping Approach Based on Ontology Semantics

    Directory of Open Access Journals (Sweden)

    Jinkui Hou

    2013-09-01

    Full Text Available The mapping relations between different models are the foundation for model transformation in model-driven software development. On the basis of ontology semantics, model mappings between different levels are classified by using structural semantics of modeling languages. The general definition process for mapping relations is explored, and the principles of structure mapping are proposed subsequently. The approach is further illustrated by the mapping relations from class model of object oriented modeling language to the C programming codes. The application research shows that the approach provides a theoretical guidance for the realization of model mapping, and thus can make an effective support to model-driven software development

  11. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention

    DEFF Research Database (Denmark)

    Tonino, Pim A L; De Bruyne, Bernard; Pijls, Nico H J

    2009-01-01

    BACKGROUND: In patients with multivessel coronary artery disease who are undergoing percutaneous coronary intervention (PCI), coronary angiography is the standard method for guiding the placement of the stent. It is unclear whether routine measurement of fractional flow reserve (FFR; the ratio......-eluting stents guided by angiography alone or guided by FFR measurements in addition to angiography. Before randomization, lesions requiring PCI were identified on the basis of their angiographic appearance. Patients assigned to angiography-guided PCI underwent stenting of all indicated lesions, whereas those...

  12. Aneurysmal re-rupture during selective cerebral angiography

    Energy Technology Data Exchange (ETDEWEB)

    Zaehringer, Markus; Gossmann, Axel; Krueger, Karsten; Trenschel, Gertrud; Landwehr, Peter [Department of Radiology, University of Cologne, Joseph-Stelzmann-Strasse 9, 50924 Cologne (Germany); Wedekind, Christoph [Department of Neurosurgery, University of Cologne, Joseph-Stelzmann-Strasse 9, 50924 Cologne (Germany)

    2002-07-01

    Two cases of aneurysmal re-rupture during intracranial angiography are presented. This event is accompanied by disastrous consequences with regard to the clinical condition of the patient, as is evident from the cases presented as well as from the literature. Acute alterations of intraluminal pressure as well as a time interval of less than 6 h seems to increase the risk of re-bleeding during angiography. The introduction of and the growing experience with CT and MR angiography may in the near future provide sufficient diagnostic information for surgical planning and thus help to overcome the risk of aneurysmal re-rupture during intra-arterial angiography. (orig.)

  13. Multidetector computed tomography pulmonary angiography in childhood acute pulmonary embolism

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chun Xiang; Zhang, Long Jiang; Lu, Guang Ming [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Schoepf, U.J. [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Department of Pediatrics, Charleston, SC (United States); Chowdhury, Shahryar M. [Medical University of South Carolina, Department of Pediatrics, Charleston, SC (United States); Fox, Mary A. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States)

    2015-09-15

    Pulmonary embolism is a life-threatening condition affecting people of all ages. Multidetector row CT pulmonary angiography has improved the imaging of pulmonary embolism in both adults and children and is now regarded as the routine modality for detection of pulmonary embolism. Advanced CT pulmonary angiography techniques developed in recent years, such as dual-energy CT, have been applied as a one-stop modality for pulmonary embolism diagnosis in children, as they can simultaneously provide anatomical and functional information. We discuss CT pulmonary angiography techniques, common and uncommon findings of pulmonary embolism in both conventional and dual-energy CT pulmonary angiography, and radiation dose considerations. (orig.)

  14. Abstract algebra an inquiry based approach

    CERN Document Server

    Hodge, Jonathan K; Sundstrom, Ted

    2013-01-01

    ""This book arose from the authors' approach to teaching abstract algebra. They place an emphasis on active learning and on developing students' intuition through their investigation of examples. … The text is organized in such a way that it is possible to begin with either rings or groups.""-Florentina Chirtes, Zentralblatt MATH 1295

  15. Quality of abdominal computed tomography angiography: hand versus mechanical intravenous contrast administration in children

    Energy Technology Data Exchange (ETDEWEB)

    Ayyala, Rama S.; Lee, Edward Y. [Boston Children' s Hospital and Harvard Medical School, Department of Radiology, Boston, MA (United States); Zurakowski, David [Boston Children' s Hospital and Harvard Medical School, Departments of Anesthesiology and Surgery, Boston, MA (United States)

    2015-11-15

    Abdominal CT angiography has been increasingly used for evaluation of various conditions related to abdominal vasculature in the pediatric population. However, no direct comparison has evaluated the quality of abdominal CT angiography in children using hand versus mechanical administration of intravenous (IV) contrast agent. To compare hand versus mechanical administration of IV contrast agent in the quality of abdominal CT angiography in the pediatric population. We retrospectively reviewed the electronic medical record to identify pediatric patients (≤18 years) who had abdominal CT angiography between August 2012 and August 2013. The information obtained includes: (1) type of administration of IV contrast agent (hand [group 1] versus mechanical [group 2]), (2) size (gauge) of IV catheter, (3) amount of contrast agent administered and (4) rate of contrast agent administration (ml/s). Two reviewers independently performed qualitative and quantitative evaluation of abdominal CT angiography image quality. Qualitative evaluation of abdominal CT angiography image quality was performed by visual assessment of the degree of contrast enhancement in the region of interest (ROI) based on a 4-point scale. Quantitative evaluation of each CT angiography examination was performed by measuring the Hounsfield unit (HU) using an ROI within the abdominal aorta at two levels (celiac axis and the inferior mesenteric artery) for each child. Analysis of variance (ANOVA) using the F-test was applied to compare contrast enhancement within the abdominal aorta at two levels (celiac axis and inferior mesenteric artery) between hand administration and mechanical administration of IV contrast methods with adjustment for age. We identified 46 pediatric patients (24 male, 22 female; mean age 7.3 ± 5.5 years; range 5 weeks to 18 years) with abdominal CT angiography performed during the study period. Of these patients, 16 (35%; 1.7 ± 2.2 years; range 5 weeks to 5 years) had hand

  16. Statistical analysis of motion contrast in optical coherence tomography angiography

    CERN Document Server

    Cheng, Yuxuan; Pan, Cong; Lu, Tongtong; Hong, Tianyu; Ding, Zhihua; Li, Peng

    2015-01-01

    Optical coherence tomography angiography (Angio-OCT), mainly based on the temporal dynamics of OCT scattering signals, has found a range of potential applications in clinical and scientific researches. In this work, based on the model of random phasor sums, temporal statistics of the complex-valued OCT signals are mathematically described. Statistical distributions of the amplitude differential (AD) and complex differential (CD) Angio-OCT signals are derived. The theories are validated through the flow phantom and live animal experiments. Using the model developed in this work, the origin of the motion contrast in Angio-OCT is mathematically explained, and the implications in the improvement of motion contrast are further discussed, including threshold determination and its residual classification error, averaging method, and scanning protocol. The proposed mathematical model of Angio-OCT signals can aid in the optimal design of the system and associated algorithms.

  17. An eigenvector based approach to neutrino mixing

    CERN Document Server

    Sierra, D Aristizabal; Houet, E

    2013-01-01

    We propose a model-independent analysis of the neutrino mass matrix through an expansion in terms of the eigenvectors defining the lepton mixing matrix, which we show can be parametrized as small perturbations of the tribimaximal mixing eigenvectors. This approach proves to be powerful and convenient for some aspects of lepton mixing, in particular when studying the sensitivity of the mass matrix elements to departures from their tribimaximal form. In terms of the eigenvector decomposition, the neutrino mass matrix can be understood as originating from a tribimaximal dominant structure with small departures determined by data. By implementing this approach to cases when the neutrino masses originate from different mechanisms, we show that the experimentally observed structure arises very naturally. We thus claim that the observed deviations from the tribimaximal mixing pattern might be interpreted as a possible hint of a ``hybrid'' nature of the neutrino mass matrix.

  18. Evaluating a Pivot-Based Approach for Bilingual Lexicon Extraction

    Directory of Open Access Journals (Sweden)

    Jae-Hoon Kim

    2015-01-01

    Full Text Available A pivot-based approach for bilingual lexicon extraction is based on the similarity of context vectors represented by words in a pivot language like English. In this paper, in order to show validity and usability of the pivot-based approach, we evaluate the approach in company with two different methods for estimating context vectors: one estimates them from two parallel corpora based on word association between source words (resp., target words and pivot words and the other estimates them from two parallel corpora based on word alignment tools for statistical machine translation. Empirical results on two language pairs (e.g., Korean-Spanish and Korean-French have shown that the pivot-based approach is very promising for resource-poor languages and this approach observes its validity and usability. Furthermore, for words with low frequency, our method is also well performed.

  19. Parallel Graph Transformation based on Merged Approach

    Directory of Open Access Journals (Sweden)

    Asmaa Aouat

    2013-01-01

    Full Text Available Graph transformation is one of the key concepts in graph grammar. In order to accelerate the graph transformation, the concept of parallel graph transformation has been proposed by different tools such as AGG tool. The theory of parallel graph transformation used by AGG just allows clarifying the concepts of conflict and dependency between the transformation rules. This work proposes an approach of parallel graph transformations which enables dependent transformation rules to be executed in parallel.

  20. Supraorbital eyebrow approach to skull base lesions

    Directory of Open Access Journals (Sweden)

    Fernandes Yvens Barbosa

    2002-01-01

    Full Text Available We report our experience with a supraorbital eyebrow minicraniotomy. This technique is suitable to lesions situated in the region of the anterior fossa, suprasellar cisterns, parasellar region and Sylvian fissure. A 50 mm incision in the eyebrow and a supraorbital minicraniotomy is performed. Sixteem patients harboring different lesions were operated on with good postoperative and cosmetic results. We conclude that this approach is safe and useful in selected cases.

  1. A polyhedral approach to computing border bases

    CERN Document Server

    Braun, Gábor

    2009-01-01

    Border bases can be considered to be the natural extension of Gr\\"obner bases that have several advantages. Unfortunately, to date the classical border basis algorithm relies on (degree-compatible) term orderings and implicitly on reduced Gr\\"obner bases. We adapt the classical border basis algorithm to allow for calculating border bases for arbitrary degree-compatible order ideals, which is \\emph{independent} from term orderings. Moreover, the algorithm also supports calculating degree-compatible order ideals with \\emph{preference} on contained elements, even though finding a preferred order ideal is NP-hard. Effectively we retain degree-compatibility only to successively extend our computation degree-by-degree. The adaptation is based on our polyhedral characterization: order ideals that support a border basis correspond one-to-one to integral points of the order ideal polytope. This establishes a crucial connection between the ideal and the combinatorial structure of the associated factor spaces.

  2. Evaluation of the effect of music on anxiety level of patients hospitalized in cardiac wards before angiography

    Directory of Open Access Journals (Sweden)

    Pourmovahed Zahra

    2016-08-01

    Full Text Available Background and Objective: Patients experience high levels of anxiety before angiography, which is mostly associated with irreparable effects on health status of such individuals. Use of alternative medicine to reduce stress and anxiety is of paramount importance. Therefore, this study aimed to evaluate the effect of music on anxiety level of patients hospitalized in cardiac wards before angiography. Materials and Method: This clinical trial was conducted on 70 patients admitted to cardiac wards before angiography in three selected hospitals of Shiraz, Iran in 2015. Samples were randomized convenience sampling and divided into two groups of control (n=35 and intervention (n=35. In this study, the intervention group received one hour of music before angiography for 20 minutes, whereas the usual care of ward was provided for the control group. Data was collected using the state-trait anxiety inventory (STAI by Spielberger one hour before angiography (immediately before the intervention and 20 minutes after angiography (immediately after the intervention through interviews with all the participants. Data analysis was performed in SPSS version 22 using descriptive statistics, Chi-square, as well as paired and independent-tests. Results: In this study, mean anxiety scores of patients in the intervention and control groups before the intervention were 48.45±6.63 and 48.25±6.63, respectively. After the intervention, these scores were changed to 44.28±5.21 and 49.02±7.74 in the intervention (P=0.004 and control (P=0.90 groups, respectively. Therefore, a significant difference was observed between the groups after the intervention (P=0.008. Conclusion: According to the results of this study, music before angiography could lead to a significant decrease in anxiety level of patients. Therefore, this approach could be used as an effective method to alleviate anxiety in patients.

  3. Evaluation of the effect of music on anxiety level of patients hospitalized in cardiac wards before angiography

    Directory of Open Access Journals (Sweden)

    Zahra Pourmovahed

    2016-02-01

    Full Text Available Background: Patients experience high levels of anxiety before angiography, which is mostly associated with irreparable effects on health status of such individuals. Use of alternative medicine to reduce stress and anxiety is of paramount importance. Therefore, this study aimed to evaluate the effect of music on anxiety level of patients hospitalized in cardiac wards before angiography. Methods: This clinical trial was conducted on 70 patients admitted to cardiac wards before angiography in three selected hospitals of Shiraz, Iran in 2015. Samples were selected through randomized and available sampling and divided into two groups of control (n=35 and intervention (n=35. In this study, the intervention group received one hour of music before angiography for 20 minutes, whereas the usual care of ward was provided for the control group. Data was collected using the state-trait anxiety inventory (STAI by Spielberger one hour before angiography (immediately before the intervention and 20 minutes after angiography (immediately after the intervention through interviews with all the participants. Data analysis was performed in SPSS version 22 using descriptive statistics, Chi-square, as well as paired and independent-tests. Results: In this study, mean anxiety scores of patients in the intervention and control groups before the intervention were 48.45±6.63 and 48.25±6.63, respectively. After the intervention, these scores were changed to 44.28±5.21 and 49.02±7.74 in the intervention (P=0.004 and control (P=0.90 groups, respectively. Therefore, a significant difference was observed between the groups after the intervention (P=0.008. Conclusion: According to the results of this study, music before angiography could lead to a significant decrease in anxiety level of patients. Therefore, this approach could be used as an effective method to alleviate anxiety in patients.

  4. Contrast-enhanced MR angiography of abdominal vessels: Is there still a role for angiography?

    Energy Technology Data Exchange (ETDEWEB)

    Vosshenrich, R.; Fischer, U. [Department of Radiology, Georg-August-Universitaet Goettingen (Germany)

    2002-01-01

    The purpose of this review article is to describe recent advantages in contrast-enhanced (CE) three-dimensional (3D) magnetic resonance angiography (MRA) in comparison with other vascular imaging techniques, and to discuss their current clinical applications for the imaging of abdominal vessels. Principles and technical considerations are presented and clinical applications are reviewed for different vascular diseases. In ruptured aortic aneurysms and acute dissections CT is the method of first choice. Contrast-enhanced 3D MRA can be well used for therapeutic planning and follow-up in patients with stable disease. A comprehensive MR examination including CE 3D MRA, MR urography and MR nephrogram has the potential to replace the conventional studies for the evaluation of renal vascular disease. It is an accurate method for imaging the origins of coeliac and superior mesenteric arteries, although the image resolution is too low for reliable assessment of the inferior mesenteric artery. Contrast-enhanced 3D MRA has emerged as the method of choice for studying the portal venous system in liver transplant recipients, in patients with portal hypertension and in cases with abdominal tumours for preoperative evaluation. Additional non-invasive flow measurements are useful in monitoring portal hypertension. The abdominal veins can be well imaged using unenhanced MR techniques. Imaging may be facilitated with intravascular contrast media. Contrast-enhanced 3D MRA can replace intra-arterial DSA for diagnosis, therapy planning and follow-up in patients with abdominal vascular disease. Catheter-based arteriography will still be used for interventional procedures such as percutaneous transluminal angioplasty, stent placement and embolisation. (orig.)

  5. A Task-based Approach to Materials Development

    OpenAIRE

    2010-01-01

    The purpose of this chapter is to present a task-based approach to materials development. In the first part of the chapter, I sketch out the evolution of task based language teaching, drawing on a distinction between synthetic and analytical approaches to syllabus design first articulated by Wilkins (1976).

  6. A strength-based approach to teacher professional development

    NARCIS (Netherlands)

    Zwart, Rosanne; Korthagen, Fred A J; Attema-Noordewier, Saskia

    2015-01-01

    Based on positive psychology, self-determination theory and a perspective on teacher quality, this study proposes and examines a strength-based approach to teacher professional development. A mixed method pre-test/post-test design was adopted to study perceived outcomes of the approach for 93 teache

  7. A strength-based approach to teacher professional development

    NARCIS (Netherlands)

    Zwart, Rosanne C.; Korthagen, Fred A J; Attema-Noordewier, Saskia

    2014-01-01

    Based on positive psychology, self-determination theory and a perspective on teacher quality, this study proposes and examines a strength-based approach to teacher professional development. A mixed method pre-test/post-test design was adopted to study perceived outcomes of the approach for 93 teache

  8. Thinning based Antialiasing Approach for Visual Saliency of Digital Images

    NARCIS (Netherlands)

    Rukundo, O.

    2015-01-01

    A thinning based approach for spatial antialiasing (TAA) has been proposed for visual saliency of digital images. This TAA approach is based on edge-matting and digital compositing strategies. Prior to edgematting the image edges are detected using ant colony optimization (ACO) algorithm and then th

  9. EFL Reading Instruction: Communicative Task-Based Approach

    Science.gov (United States)

    Sidek, Harison Mohd

    2012-01-01

    The purpose of this study was to examine the overarching framework of EFL (English as a Foreign Language) reading instructional approach reflected in an EFL secondary school curriculum in Malaysia. Based on such analysis, a comparison was made if Communicative Task-Based Language is the overarching instructional approach for the Malaysian EFL…

  10. A Task-based Approach to Materials Development

    Directory of Open Access Journals (Sweden)

    David Nunan

    2010-07-01

    Full Text Available The purpose of this chapter is to present a task-based approach to materials development. In the first part of the chapter, I sketch out the evolution of task based language teaching, drawing on a distinction between synthetic and analytical approaches to syllabus design first articulated by Wilkins (1976.

  11. A Strength-Based Approach to Teacher Professional Development

    Science.gov (United States)

    Zwart, Rosanne C.; Korthagen, Fred A. J.; Attema-Noordewier, Saskia

    2015-01-01

    Based on positive psychology, self-determination theory and a perspective on teacher quality, this study proposes and examines a strength-based approach to teacher professional development. A mixed method pre-test/post-test design was adopted to study perceived outcomes of the approach for 93 teachers of six primary schools in the Netherlands and…

  12. Antirandom Testing: A Distance-Based Approach

    Directory of Open Access Journals (Sweden)

    Shen Hui Wu

    2008-01-01

    Full Text Available Random testing requires each test to be selected randomly regardless of the tests previously applied. This paper introduces the concept of antirandom testing where each test applied is chosen such that its total distance from all previous tests is maximum. This spans the test vector space to the maximum extent possible for a given number of vectors. An algorithm for generating antirandom tests is presented. Compared with traditional pseudorandom testing, antirandom testing is found to be very effective when a high-fault coverage needs to be achieved with a limited number of test vectors. The superiority of the new approach is even more significant for testing bridging faults.

  13. MR angiography is a great boon for children with moyamoya disease

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Takashi; Wakisaka, Shinichiro; Kodama, Takao; Watanabe, Katsushi (Miyazaki Medical Coll., Kiyotake (Japan))

    1993-04-01

    Magnetic resonance angiography (MRA) films of 15 pediatric patients with moyamoya disease diagnosed with conventional angiography and of 11 children with suspected moyamoya disease were reviewed to evaluate the ability of MRA to demonstrate vascular abnormalities. We performed MRA with a superconductive 1.5-tesla MR system which employs a 3D-field echo technique based on the time-of-flight (TOF) effect. The typical MRA findings of moyamoya disease were; stenosis or obstruction of the terminal segment of the internal carotid arteries and the proximal segments of the anterior and middle cerebral arteries, plus well-developed basal moyamoya vessels, ophthalmic arteries, posterior cerebral arteries and leptomeningeal anastomoses. Retrograde filling through the superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis was visible, but fine vessels through the encephalo-myo-synangiosis were rarely seen. Stenosis of the artery was over-diagnosed because of the exaggerated turbulent flow seen in MRA. The natural course of asymptomatic, early stage, unilateral and hemorrhagic types of moyamoya disease and its pathophysiology are still unknown. MRA is a much better way to obtain anatomical and physiological information about the vascular structure and blood flow without any stress to the patient than is conventional angiography. Therefore, it promises to become a valuable alternative to conventional angiography not only for the diagnosis of moyamoya disease but also for treatment planning. (author).

  14. Multi-section CT angiography compared with digital subtraction angiography in diagnosing major arterial hemorrhage in inflammatory pancreatic disease

    Energy Technology Data Exchange (ETDEWEB)

    Hyare, Harpreet [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom)]. E-mail: hhyare@doctors.org.uk; Desigan, Sharmini [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom); Nicholl, Helen [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom); Guiney, Michael J. [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom); Brookes, Jocelyn A. [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom); Lees, William R. [Department of Imaging, University College London Hospitals NHS Foundation Trust, University College Hospital, 235 Euston Road, London NW1 2BU (United Kingdom)

    2006-08-15

    Purpose: Major arterial hemorrhage is an uncommon but serious complication of pancreatitis with high morbidity and mortality. Digital subtraction angiography (DSA) has long been the gold standard for the detection of a visceral artery pseudoaneurysm or for the site of active bleeding in patients with pancreatitis. Multi-section CT angiography is a minimally invasive technique which can provide high-resolution and high-contrast images of the arterial lumen and wall, with a much lower risk of complication and morbidity compared to DSA. The aim of this study was to determine the accuracy of multi-section CT angiography for the diagnosis of arterial complications of inflammatory pancreatitic disease. Materials and methods: A retrospective analysis of all patients undergoing visceral angiography for major bleeding as a complication of pancreatitis between 1998 and 2004 was performed. Twenty-nine studies in 25 patients (20 males, 5 females) with a mean age of 50.9 years (range 11-67 years) were identified where multi-section CT angiography was performed in the 24 h preceding the digital subtraction angiogram. Results: Digital subtraction angiography detected a pseudoaneurysm or contrast extravasation in 19 studies and no bleeding was demonstrated in 9 studies. CT angiography correctly identified the site and type of bleeding in 18 of the 19 positive studies. CT angiography detected extravasation of contrast in one study that was not demonstrated on digital subtraction angiography. The sensitivity and specificity for multi-section CT angiography for the detection of major arterial bleeding on a background of pancreatitis were 0.947 and 0.900, respectively. Conclusion: Multi-section CT angiography is a sensitive and accurate technique for the detection of major arterial hemorrhage in inflammatory pancreatic disease and should be considered as the first investigation in the management of these patients.

  15. A model-based multisensor data fusion knowledge management approach

    Science.gov (United States)

    Straub, Jeremy

    2014-06-01

    A variety of approaches exist for combining data from multiple sensors. The model-based approach combines data based on its support for or refutation of elements of the model which in turn can be used to evaluate an experimental thesis. This paper presents a collection of algorithms for mapping various types of sensor data onto a thesis-based model and evaluating the truth or falsity of the thesis, based on the model. The use of this approach for autonomously arriving at findings and for prioritizing data are considered. Techniques for updating the model (instead of arriving at a true/false assertion) are also discussed.

  16. [Intraoperative verification of a perforator flap vascularization by indocyanine green angiography].

    Science.gov (United States)

    Royer, E; Rausky, J; Binder, J-P; May, P; Virzi, D; Revol, M

    2014-02-01

    After Koshima and Soeda first described perforator flaps in 1988, Wei has improved the technique by describing the "free style perforator flap". These flaps have the advantage of being performed on all skin perforators and in reducing donor site morbidity. The disadvantage, however is that the size of their angiosome is not defined and the evaluation of their relay on the experience of the surgeon. An evaluation of the size of an angiosome by conducting intraoperative angiography is proposed. Intraoperative angiography is performed after injection of indocyanine green. Stimulation of the indocyanine green by infrared causes the emission of fluorescent radiation. This fluorescence is then detected by a specific camera that displays real-time visualization of the skin's perfusion. We present the case of a 39-year-old patient who had an open tibial pilon fracture, for which we performed a pedicled propeller flap based on a posterior tibial perforator. Angiography was used to determine accurately the optimal skin perfusion of the propeller flap, which was based on a perforator from the posterior tibial artery. Angiography identified several levels of skin perfusion with a high fluorescence, intermediate and absent. The non-vascularized part of the skin paddle was resected. Given the unreliability of this technique, hypoperfused area was retained. Debridment of this area, however was necessary at day 5 postoperative with repositionning of the flap. Indocyanine green angiography may be a useful decision-making tool for intraoperative surgeon. It allows to adjust the size of the propeller flap's skin paddle to it angiosome. However, this evaluation method needs to be improved with the introduction of a quantitative threshold.

  17. A New Text Location Approach Based Wavelet

    Institute of Scientific and Technical Information of China (English)

    Weihua Li; Zhen Fang; Shuozhong Wang

    2002-01-01

    With the advancement of content-based retrieval technology, the importance of semantics for text information contained in images attracts many researchers. An algorithm which will automatically locate the textual regions in the input image will facilitate the retrieving task, and the optical character recognizer can then be applied to only those regions of the image which contain text. In this paper a new text location method based wavelet is described, which can be used to locate textual regions from complex image and video frame. Experimental results show that the textual regions in image can be located effectively and quickly.

  18. Evolutionary algorithm based configuration interaction approach

    CERN Document Server

    Chakraborty, Rahul

    2016-01-01

    A stochastic configuration interaction method based on evolutionary algorithm is designed as an affordable approximation to full configuration interaction (FCI). The algorithm comprises of initiation, propagation and termination steps, where the propagation step is performed with cloning, mutation and cross-over, taking inspiration from genetic algorithm. We have tested its accuracy in 1D Hubbard problem and a molecular system (symmetric bond breaking of water molecule). We have tested two different fitness functions based on energy of the determinants and the CI coefficients of determinants. We find that the absolute value of CI coefficients is a more suitable fitness function when combined with a fixed selection scheme.

  19. Web Based ‘C’ IDE: Approach

    Directory of Open Access Journals (Sweden)

    Sravanthi Emani

    2012-03-01

    Full Text Available A Web based environment has been designed to execute C programs without explicitly installing any compilers on the machine, thus addressing the concerns of portability and accessibility. Theenvironment runs on a Linux server, uses password authentication and provides each user with separate project directories to store all his programs. These can be accessed and modified by the respective useronly. The entered code can be compiled and executed easily without using licensed software for the same. This saves installation time as well as memory of the client machine. The configuration of the machineneed not be an issue as the system is web based and thus platform independent.

  20. Face Recognition Based on Nonlinear Feature Approach

    Directory of Open Access Journals (Sweden)

    Eimad E.A. Abusham

    2008-01-01

    Full Text Available Feature extraction techniques are widely used to reduce the complexity high dimensional data. Nonlinear feature extraction via Locally Linear Embedding (LLE has attracted much attention due to their high performance. In this paper, we proposed a novel approach for face recognition to address the challenging task of recognition using integration of nonlinear dimensional reduction Locally Linear Embedding integrated with Local Fisher Discriminant Analysis (LFDA to improve the discriminating power of the extracted features by maximize between-class while within-class local structure is preserved. Extensive experimentation performed on the CMU-PIE database indicates that the proposed methodology outperforms Benchmark methods such as Principal Component Analysis (PCA, Fisher Discrimination Analysis (FDA. The results showed that 95% of recognition rate could be obtained using our proposed method.

  1. Coronary CT angiography in symptomatic patients

    Energy Technology Data Exchange (ETDEWEB)

    Becker, C.R. [Inst. of Radiologic Diagnostic, Univ. of Munich, Klinikum Grosshadern, Munich (Germany)

    2005-02-01

    The currently best available spatial and temporal resolution for retrospectively ECG gated coronary multi-detector-row CT angiography is 0.4 mm and 165 ms, respectively. These acquisition parameters are already rather close to cardiac catheter. Studies so far compared non-invasive coronary CT and convention angiography for the detection of coronary artery stenoses. The most promising result reported by all authors was the high negative predictive value of the CTA. It now needs to be determined if CTA is a reliable tool to rule out coronary artery stenoses in a patient cohort with low likelihood of CAD, such as those with atypical chest pain or ambiguous stress test. CTA may furthermore establish as a rapid and widely available tool to detect vulnerable plaques or intracoronary thrombus in patients with acute coronary syndrome and unstable angina. In patients with chronic stable angina, tools that determine myocardial ischemia under stress such as SPECT and MRI are probably better suited to determine the relevance of coronary artery stenoses. In this particular cohort, by displaying the extent and morphology of coronary atherosclerosis, CTA may help to direct the therapy to either intervention or surgery. (orig.)

  2. Magnetic resonance angiography in suspected cerebral vasculitis

    Energy Technology Data Exchange (ETDEWEB)

    Demaerel, Philippe; De Ruyter, Nele; Wilms, Guido [Department of Radiology, Universitair Ziekenhuis, KU Leuven, 3000, Leuven (Belgium); Maes, Frederik [Department of Medical Imaging Computing, Universitair Ziekenhuis, KU Leuven, 3000, Leuven (Belgium); Velghe, Beatrijs [Department of Radiology, Ziekenhuis Oost-Limburg, Schiepse Bos 6, 3600, Genk (Belgium)

    2004-06-01

    The purpose of this study was to determine the technical capacity and diagnostic accuracy of 3D time-of-flight magnetic resonance angiography (MRA) in suspected cerebral vasculitis in a retrospective analysis of MRA and digital subtraction angiography (DSA) in 14 young patients with clinical and/or radiological suspicion of cerebral vasculitis. A total of nine arteries were evaluated in each patient. Consensus review of DSA by three observers was the reference standard. The sensitivity for detecting a stenosis varied from 62 to 79% for MRA and from 76 to 94% for DSA, depending on the observer. The specificity for detecting a stenosis varied from 83 to 87% for MRA and from 83 to 97% for DSA. Using the criterion ''more than two stenoses in at least two separate vascular distributions'' to consider the examination as being true positive, the false-positive rates for MRA and DSA were comparable. MRA plays a role as the first angiographical examination in the diagnostic work-up of suspected cerebral vasculitis. When more than two stenoses in at least two separate vascular distributions are depicted on MRA, DSA is not expected to add a significant diagnostic contribution in a patient with suspected cerebral vasculitis. DSA remains necessary when MRA is normal or when less than three stenoses are seen. (orig.)

  3. Non-contrast-enhanced MR angiography of the abdomen

    Energy Technology Data Exchange (ETDEWEB)

    Miyazaki, Mitsue, E-mail: mmiyazaki@tmriusa.com [Toshiba Medical Research Institute, USA, 706N. Deerpath Dr., Vernon Hills, IL 60061 (United States); Isoda, Hiroyoshi [Toshiba Medical Research Institute, USA, 706N. Deerpath Dr., Vernon Hills, IL 60061 (United States); Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University, Kyoto (Japan)

    2011-10-15

    Non-contrast-enhanced magnetic resonance angiography (MRA) techniques have experienced a resurgence of interest in the MR community, in part because of safety concerns related to the possible link between gadolinium-based contrast agents and nephrogenic systemic fibrosis (NSF). In abdominal MRA, NSF is of particular concern, given that many of the patients may have renal disease. After introducing various non-contrast-enhanced MRA techniques, this article focuses on MRA applications in the abdomen, specifically the renal arteries and portal and hepatic veins. Developments on the horizon are discussed, including techniques that provide standardization of renal artery imaging, challenges in imaging of the hepatic arteries, and further advancement at 3 T.

  4. K-Edge Subtraction Angiography with Synchrotron X-Rays

    CERN Document Server

    Giacomini, J C

    1996-01-01

    The purpose of this project was to utilize dual energy, monochromatic X-rays produced from synchrotrons radiation in order to obtain noninvasive medical imaging. The application of synchrotrons radiation to medical imaging is based on the principle of iodine dichromography, first described by Bertil Jacobson of the Karolinska Institute in 1953. Medical imaging using synchrotrons radiation and K-edge dichromography was pioneered at Stanford University under the leadership of Dr. Ed Rubenstein, and the late Nobel Laureate in Physics, Dr. Robert Hofstadter. With progressive refinements in hardware, clinical-quality images were obtained of human coronary arteries utilizing peripheral injections of iodinated contrast agent. These images even now are far superior to those being presented by investigators using MRI as an imaging tool for coronary arteries. However, new supplies and instruments in the cardiac catheterization laboratory have served to transform coronary angiography into an outpatient procedure, with r...

  5. Algebraic Verification Method for SEREs Properties via Groebner Bases Approaches

    Directory of Open Access Journals (Sweden)

    Ning Zhou

    2013-01-01

    Full Text Available This work presents an efficient solution using computer algebra system to perform linear temporal properties verification for synchronous digital systems. The method is essentially based on both Groebner bases approaches and symbolic simulation. A mechanism for constructing canonical polynomial set based symbolic representations for both circuit descriptions and assertions is studied. We then present a complete checking algorithm framework based on these algebraic representations by using Groebner bases. The computational experience result in this work shows that the algebraic approach is a quite competitive checking method and will be a useful supplement to the existent verification methods based on simulation.

  6. Moyamoya disease: diagnosis with three-dimensional CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, K. (Dept. of Radiology, National Defense Medical Coll., Saitama (Japan) Dept. of Radiology, Kyorin Univ. School of Medicine, Tokyo (Japan)); Makita, K. (Dept. of Radiology, National Defense Medical Coll., Saitama (Japan) Dept. of Radiology, Social Health Insurance Medical Center, Tokyo (Japan)); Furui, S. (Dept. of Radiology, National Defense Medical Coll., Saitama (Japan) Dept. of Diagnostic Radiology, Toranomon Kyosai Hospital, Tokyo (Japan))

    1994-08-01

    Our purpose was to assess the value of three-dimensional (3D) CT angiography in the diagnosis of moyamoya disease. We studied seven patients with moyamoya disease proved by conventional angiography. Three-dimensional (3D) CT angiography was performed using rapid sequence or helical (spiral) scanning in conjunction with a bolus injection of intravenous contrast medium. All seven patients could be diagnosed as having moyamoya disease on the basis of the following 3D CT angiographic findings: poor visualisation of the main trunks and/or major branches of anterior and middle cerebral arteries (7 patients); dilated leptomeningeal anastomotic channels from the posterior cerebral arteries (4); and demonstration of ''moyamoya vessels'' in the basal ganglia (2). Although conventional angiography remains the principal imaging technique for demonstrating anatomical changes in detail, less invasive 3D CT angiography provides a solid means of diagnosing moyamoya disease when it is suspected on CT, MRI, or clinical grounds. (orig.)

  7. One Piece Orbitozygomatic Approach Based on the Sphenoid Ridge Keyhole

    DEFF Research Database (Denmark)

    Spiriev, Toma; Poulsgaard, Lars; Fugleholm, Kaare

    2016-01-01

    The one-piece orbitozygomatic (OZ) approach is traditionally based on the McCarty keyhole. Here, we present the use of the sphenoid ridge keyhole and its possible advantages as a keyhole for the one-piece OZ approach. Using transillumination technique the osteology of the sphenoid ridge was exami......The one-piece orbitozygomatic (OZ) approach is traditionally based on the McCarty keyhole. Here, we present the use of the sphenoid ridge keyhole and its possible advantages as a keyhole for the one-piece OZ approach. Using transillumination technique the osteology of the sphenoid ridge...

  8. SLAM - Based Approach to Dynamic Ship Positioning

    Directory of Open Access Journals (Sweden)

    Krzysztof Wrobel

    2014-03-01

    Full Text Available Dynamically positioned vessels, used by offshore industry, use not only satellite navigation but also different positioning systems, often referred to as reference' systems. Most of them use multiple technical devices located outside the vessel which creates some problems with their accessibility and performance. In this paper, a basic concept of reference system independent from any external device is presented, basing on hydroacoustics and Simultaneous Localization and Mapping (SLAM method. Theoretical analysis of its operability is also performed.

  9. Nanotechnology-Based Approach in Tuberculosis Treatment

    Science.gov (United States)

    Neyaz, Md. Kausar; Das, Shilpi

    2017-01-01

    Tuberculosis, commonly known as TB, is the second most fatal infectious disease after AIDS, caused by bacterium called Mycobacterium tuberculosis. Prolonged treatment, high pill burden, low compliance, and stiff administration schedules are factors that are responsible for emergence of MDR and XDR cases of tuberculosis. Till date, only BCG vaccine is available which is ineffective against adult pulmonary TB, which is the most common form of disease. Various unique antibodies have been developed to overcome drug resistance, reduce the treatment regimen, and elevate the compliance to treatment. Therefore, we need an effective and robust system to subdue technological drawbacks and improve the effectiveness of therapeutic drugs which still remains a major challenge for pharmaceutical technology. Nanoparticle-based ideology has shown convincing treatment and promising outcomes for chronic infectious diseases. Different types of nanocarriers have been evaluated as promising drug delivery systems for various administration routes. Controlled and sustained release of drugs is one of the advantages of nanoparticle-based antituberculosis drugs over free drug. It also reduces the dosage frequency and resolves the difficulty of low poor compliance. This paper reviews various nanotechnology-based therapies which can be used for the treatment of TB. PMID:28210505

  10. Media approach to gender-based violence

    Directory of Open Access Journals (Sweden)

    Mršević Zorica

    2012-01-01

    Full Text Available The author grounds her research and the latter analysis on continually conducted daily press-clipping of seven main printed daily newspapers and two main electronic media in Serbia, within the three years period (2009 - 2011. An analysis of media reports on gender based violence, with particular focus on the most frequent domestic violence cases within the two years period, 2010 to 2011 is presented. As the best of media reports on gender based violence, the author stressed out its „whistle blower“ role - media are the main source of information on cases, dimensions and forms of gender based violence. Also the worse moments of media reporting in the mentioned period are presented - when the violence was justified or when reality is deformed by presenting these cases as romantic love stories. For example, in 2010 the worst was reporting on the „Pajčin/Kapisoda“ case, while in 2011 it was the „Ponjiger“ case. In the end, the author also warned on the worrysome fact of sudden dissapearance of media reports on partners’ murdering their wives after the last such report published in mid-october 2011, which could mean that now we have a new problem of diminished freedom of media.

  11. Co-registration of optical coherence tomography and X-ray angiography in percutaneous coronary intervention

    DEFF Research Database (Denmark)

    Hebsgaard, Lasse; Nielsen, Troels Munck; Tu, Shengxian;

    2014-01-01

    . Computer based online co-registration may aid the target segment identification. Methods The DOCTOR fusion study was a prospective, single arm, observational study including patients admitted for elective PCI. Optical coherence tomography (OCT) was acquired pre-stent implantation for sizing of stents...... to the computer-based co-registration, segments of the target lesion indicated on OCT were left uncovered by stent in 14 patients (70%). Conclusion Computer based online co-registration of OCT and angiography is feasible. Frequent inaccuracies in operator based registration indicate that computer aided co......Background Intracoronary imaging provides accurate lesion delineation and precise measurements for sizing and positioning of coronary stents. During percutaneous coronary intervention (PCI), it may be challenging to identify corresponding segments between intracoronary imaging and angiography...

  12. A New Text Location Approach Based Wavelet

    Institute of Scientific and Technical Information of China (English)

    Weihua Li; Zhen Fang; Shuozhong Wang

    2002-01-01

    With the advancement of content-based retrieval technology, the importance of semantics for text information contained in images attracts many researchers. An algorithm which will automatically locate the textual regions in the input image will facilitate the retrieving task, and the optical character recognizer can then be applied to only those regions of the image which contain text. In this paper a new text location method is described, which can be used to locate textual regions from complex image and video frame. Experimental results show that the textual regions in image can be located effectively and quickly.

  13. Workflow-based approaches to neuroimaging analysis.

    Science.gov (United States)

    Fissell, Kate

    2007-01-01

    Analysis of functional and structural magnetic resonance imaging (MRI) brain images requires a complex sequence of data processing steps to proceed from raw image data to the final statistical tests. Neuroimaging researchers have begun to apply workflow-based computing techniques to automate data analysis tasks. This chapter discusses eight major components of workflow management systems (WFMSs): the workflow description language, editor, task modules, data access, verification, client, engine, and provenance, and their implementation in the Fiswidgets neuroimaging workflow system. Neuroinformatics challenges involved in applying workflow techniques in the domain of neuroimaging are discussed.

  14. Efficacy of Patient Selection for Diagnostic Coronary Angiography in Suspected Coronary Artery Disease

    Directory of Open Access Journals (Sweden)

    Francisco Flávio Costa Filho

    2015-11-01

    Full Text Available AbstractBackground:Guidelines recommend that in suspected stable coronary artery disease (CAD, a clinical (non-invasive evaluation should be performed before coronary angiography.Objective:We assessed the efficacy of patient selection for coronary angiography in suspected stable CAD.Methods:We prospectively selected consecutive patients without known CAD, referred to a high-volume tertiary center. Demographic characteristics, risk factors, symptoms and non-invasive test results were correlated to the presence of obstructive CAD. We estimated the CAD probability based on available clinical data and the incremental diagnostic value of previous non-invasive tests.Results:A total of 830 patients were included; median age was 61 years, 49.3% were males, 81% had hypertension and 35.5% were diabetics. Non-invasive tests were performed in 64.8% of the patients. At coronary angiography, 23.8% of the patients had obstructive CAD. The independent predictors for obstructive CAD were: male gender (odds ratio [OR], 3.95; confidence interval [CI] 95%, 2.70 - 5.77, age (OR for 5 years increment, 1.15; CI 95%, 1.06 - 1.26, diabetes (OR, 2.01; CI 95%, 1.40 - 2.90, dyslipidemia (OR, 2.02; CI 95%, 1.32 - 3.07, typical angina (OR, 2.92; CI 95%, 1.77 - 4.83 and previous non-invasive test (OR 1.54; CI 95% 1.05 - 2.27.Conclusions:In this study, less than a quarter of the patients referred for coronary angiography with suspected CAD had the diagnosis confirmed. A better clinical and non-invasive assessment is necessary, to improve the efficacy of patient selection for coronary angiography.

  15. Ethics education for health professionals: a values based approach.

    Science.gov (United States)

    Godbold, Rosemary; Lees, Amanda

    2013-11-01

    It is now widely accepted that ethics is an essential part of educating health professionals. Despite a clear mandate to educators, there are differing approaches, in particular, how and where ethics is positioned in training programmes, underpinning philosophies and optimal modes of assessment. This paper explores varying practices and argues for a values based approach to ethics education. It then explores the possibility of using a web-based technology, the Values Exchange, to facilitate a values based approach. It uses the findings of a small scale study to signal the potential of the Values Exchange for engaging, meaningful and applied ethics education.

  16. Similarity-Based Approaches to Natural Language Processing

    CERN Document Server

    Lee, L

    1997-01-01

    This thesis presents two similarity-based approaches to sparse data problems. The first approach is to build soft, hierarchical clusters: soft, because each event belongs to each cluster with some probability; hierarchical, because cluster centroids are iteratively split to model finer distinctions. Our second approach is a nearest-neighbor approach: instead of calculating a centroid for each class, as in the hierarchical clustering approach, we in essence build a cluster around each word. We compare several such nearest-neighbor approaches on a word sense disambiguation task and find that as a whole, their performance is far superior to that of standard methods. In another set of experiments, we show that using estimation techniques based on the nearest-neighbor model enables us to achieve perplexity reductions of more than 20 percent over standard techniques in the prediction of low-frequency events, and statistically significant speech recognition error-rate reduction.

  17. Dictionary based Approach to Edge Detection

    CERN Document Server

    Chandra, Nitish

    2015-01-01

    Edge detection is a very essential part of image processing, as quality and accuracy of detection determines the success of further processing. We have developed a new self learning technique for edge detection using dictionary comprised of eigenfilters constructed using features of the input image. The dictionary based method eliminates the need of pre or post processing of the image and accounts for noise, blurriness, class of image and variation of illumination during the detection process itself. Since, this method depends on the characteristics of the image, the new technique can detect edges more accurately and capture greater detail than existing algorithms such as Sobel, Prewitt Laplacian of Gaussian, Canny method etc which use generic filters and operators. We have demonstrated its application on various classes of images such as text, face, barcodes, traffic and cell images. An application of this technique to cell counting in a microscopic image is also presented.

  18. An Event Based Approach To Situational Representation

    CERN Document Server

    Ashish, Naveen; Mehrotra, Sharad; Venkatasubramanian, Nalini

    2009-01-01

    Many application domains require representing interrelated real-world activities and/or evolving physical phenomena. In the crisis response domain, for instance, one may be interested in representing the state of the unfolding crisis (e.g., forest fire), the progress of the response activities such as evacuation and traffic control, and the state of the crisis site(s). Such a situation representation can then be used to support a multitude of applications including situation monitoring, analysis, and planning. In this paper, we make a case for an event based representation of situations where events are defined to be domain-specific significant occurrences in space and time. We argue that events offer a unifying and powerful abstraction to building situational awareness applications. We identify challenges in building an Event Management System (EMS) for which traditional data and knowledge management systems prove to be limited and suggest possible directions and technologies to address the challenges.

  19. Ameliorated GA approach for base station planning

    Science.gov (United States)

    Wang, Andong; Sun, Hongyue; Wu, Xiaomin

    2011-10-01

    In this paper, we aim at locating base station (BS) rationally to satisfy the most customs by using the least BSs. An ameliorated GA is proposed to search for the optimum solution. In the algorithm, we mesh the area to be planned according to least overlap length derived from coverage radius, bring into isometric grid encoding method to represent BS distribution as well as its number and develop select, crossover and mutation operators to serve our unique necessity. We also construct our comprehensive object function after synthesizing coverage ratio, overlap ratio, population and geographical conditions. Finally, after importing an electronic map of the area to be planned, a recommended strategy draft would be exported correspondingly. We eventually import HongKong, China to simulate and yield a satisfactory solution.

  20. [Management of large marine ecosystem based on ecosystem approach].

    Science.gov (United States)

    Chu, Jian-song

    2011-09-01

    Large marine ecosystem (LME) is a large area of ocean characterized by distinct oceanology and ecology. Its natural characteristics require management based on ecosystem approach. A series of international treaties and regulations definitely or indirectly support that it should adopt ecosystem approach to manage LME to achieve the sustainable utilization of marine resources. In practices, some countries such as Canada, Australia, and U.S.A. have adopted ecosystem-based approach to manage their oceans, and some international organizations such as global environment fund committee have carried out a number of LME programs based on ecosystem approach. Aiming at the sustainable development of their fisheries, the regional organizations such as Caribbean Community have established regional fisheries mechanism. However, the adoption of ecosystem approach to manage LME is not only a scientific and legal issue, but also a political matter largely depending on the political will and the mutual cooperation degree of related countries.

  1. Swept Source OCT Angiography of Neovascular Macular Telangiectasia Type 2

    Science.gov (United States)

    Zhang, Qinqin; Wang, Ruikang K.; Chen, Chieh-Li; Legarreta, Andrew D.; Durbin, Mary K.; An, Lin; Sharma, Utkarsh; Stetson, Paul F.; Legarreta, John E.; Roisman, Luiz; Gregori, Giovanni; Rosenfeld, Philip J.

    2015-01-01

    Objective To image subretinal neovascularization in proliferative macular telangiectasia type 2 (MacTel2) using swept source optical coherence tomography based microangiography (OMAG). Study Design Patients with MacTel2 were enrolled in a prospective, observational study known as the MacTel Project and evaluated using a high-speed 1050nm swept-source OCT (SS-OCT) prototype system. The OMAG algorithm generated en face flow images from three retinal layers, as well as the region bounded by the outer retina and Bruch’s membrane, the choriocapillaris, and the remaining choroidal vasculature. The en face OMAG images were compared to images from fluorescein angiography (FA) and indocyanine green angiography (ICGA). Results Three eyes with neovascular MacTel2 were imaged. The neovascularization was best identified from the en face OMAG images that included a layer between the outer retinal boundary and Bruch’s membrane. OMAG images identified these abnormal vessels better than FA and were comparable to the images obtained using ICGA. In all three cases, OMAG identified choroidal vessels communicating with the neovascularization, and these choroidal vessels were evident in the two cases with ICGA imaging. In one case, monthly injections of bevacizumab reduced the microvascular complexity of the neovascularization, as well as the telangiectatic changes within the retinal microvasculature. In another case, less frequent bevacizumab therapy was associated with growth of the subretinal neovascular complex. Conclusions OMAG imaging provided detailed, depth-resolved information about subretinal neovascularization in MacTel2 eyes demonstrating superiority to FA imaging and similarities to ICGA imaging for documenting the retinal microvascular changes, the size and extent of the neovascular complex, the communications between the neovascular complex and the choroidal circulation, and the response to monthly bevacizumab therapy. PMID:26457402

  2. Comparison of magnetic resonance angiography and conventional angiography in sickle cell disease: clinical significance and realibility

    Energy Technology Data Exchange (ETDEWEB)

    Kandeel, A.Y. [Dept. of Radiology, Mansoura Univ. Hospital (Egypt); Zimmerman, R.A. [Dept. of Radiology, The Children`s Hospital of Philadelphia, PA (United States); Ohene-Frempong, K. [Div. of Hematology, The Children`s Hospital of Philadelphia, PA (United States)

    1996-07-01

    We retrospectively reviewed the medical records and conventional angiograms of 21 patients with known sickle cell disease, who underwent a total of 50 magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) studies. MRA and conventional angiography were assessed separately for evidence of stenosis or occulusion. Follow up MRI/MRA studies were also assessed for evidence of progression, regression or stability of the disease in these patients. In the carotid circulation, MRA made the correct diagnosis in 85% of the vessels evaluated with a sensitivity of 80.5% and a specificity of 94%. MRA was also found to show evidence of disease progression, more often than did MRI or the clinical condition of the patients. (orig.)

  3. Content-based, Task-based, and Participatory Approaches (I)

    Institute of Scientific and Technical Information of China (English)

    Diane Larsen-Freeman

    2012-01-01

    1. Introduction In this chapter we will be investigating three more approaches that make communication central: content-based instruction, task-based instruction, and the participatory approach. The approaches we examine in this chapter do not begin with functions, or approaches we examine in this chapter don't begin with functions, or indeed, any other language items. Instead, they give priority to process over predetermined linguistic content. In these approaches rather than "learning to use English",

  4. Enuresis in children: a case based approach.

    Science.gov (United States)

    Baird, Drew C; Seehusen, Dean A; Bode, David V

    2014-10-15

    Enuresis is defined as intermittent urinary incontinence during sleep in a child at least five years of age. Approximately 5% to 10% of all seven-year-olds have enuresis, and an estimated 5 to 7 million children in the United States have enuresis. The pathophysiology of primary nocturnal enuresis involves the inability to awaken from sleep in response to a full bladder, coupled with excessive nighttime urine production or a decreased functional capacity of the bladder. Initial evaluation should include a history, physical examination, and urinalysis. Several conditions, such as constipation, obstructive sleep apnea, diabetes mellitus, diabetes insipidus, chronic kidney disease, and psychiatric disorders, are associated with enuresis. If identified, these conditions should be evaluated and treated. Treatment of primary monosymptomatic enuresis (i.e., the only symptom is nocturnal bed-wetting in a child who has never been dry) begins with counseling the child and parents on effective behavioral modifications. First-line treatments for enuresis include bed alarm therapy and desmopressin. The choice of therapy is based on the child's age and nighttime voiding patterns, and the desires of the child and family. Referral to a pediatric urologist is indicated for children with primary enuresis refractory to standard and combination therapies, and for children with some secondary causes of enuresis, including urinary tract malformations, recurrent urinary tract infections, or neurologic disorders.

  5. Cognitive neuroscience of creativity: EEG based approaches.

    Science.gov (United States)

    Srinivasan, Narayanan

    2007-05-01

    Cognitive neuroscience of creativity has been extensively studied using non-invasive electrical recordings from the scalp called electroencephalograms (EEGs) and event related potentials (ERPs). The paper discusses major aspects of performing research using EEG/ERP based experiments including the recording of the signals, removing noise, estimating ERP signals, and signal analysis for better understanding of the neural correlates of processes involved in creativity. Important factors to be kept in mind to record clean EEG signal in creativity research are discussed. The recorded EEG signal can be corrupted by various sources of noise and methodologies to handle the presence of unwanted artifacts and filtering noise are presented followed by methods to estimate ERPs from the EEG signals from multiple trials. The EEG and ERP signals are further analyzed using various techniques including spectral analysis, coherence analysis, and non-linear signal analysis. These analysis techniques provide a way to understand the spatial activations and temporal development of large scale electrical activity in the brain during creative tasks. The use of this methodology will further enhance our understanding the processes neural and cognitive processes involved in creativity.

  6. Simulation-Based Constructivist Approach for Education Leaders

    Science.gov (United States)

    Shapira-Lishchinsky, Orly

    2015-01-01

    The purpose of this study was to reflect the leadership strategies that may arise using a constructivist approach based on organizational learning. This approach involved the use of simulations that focused on ethical tensions in school principals' daily experiences, and the development of codes of ethical conduct to reduce these tensions. The…

  7. A Semantics-Based Approach to Retrieving Biomedical Information

    DEFF Research Database (Denmark)

    Andreasen, Troels; Bulskov, Henrik; Zambach, Sine

    2011-01-01

    This paper describes an approach to representing, organising, and accessing conceptual content of biomedical texts using a formal ontology. The ontology is based on UMLS resources supplemented with domain ontologies developed in the project. The approach introduces the notion of ‘generative...

  8. Three-dimensional CT angiography with volume rendering for the dignosis of multiple intracranial aneurysms

    Institute of Scientific and Technical Information of China (English)

    FANG Bing; LI Tie-lin; ZHANG Jian-min; DUAN Chuan-zhi; WANG Qiu-jing; ZAO Qing-ping

    2004-01-01

    Objective:To evaluate the importance of 3D-CTA with volume rendering for the diagnosis of multiple intracranial aneurysms. Methods: Axial source images were obtained by helical CT scanning and reconstruction of 3D-CTA images was done by volume rendering technique in conjunction with multiplanar reformation. Results: In the past one year,there were 10 patients diagnosed as having multiple intracranial aneurysms by 3D-CTA and altogether 24 aneurysms were visualized,including 10 small aneurysms(≤5mm.Three dimensional CT angiography with volume rendering demonstrated aneurysms very well and provided useful information concerning the site,shape,size and spatial relationship with the surrounding vessels and bone anatomy. Conclusion: Three-dimensional CT angiography with volume rendering is a quick,reliable,and relatively noninvasive method for diagnosing multiple intracranial aneurysms.It delineates detailed aneurysmal morphology,and provides useful information for planning microsurgical approaches.

  9. Coronary magnetic resonance angiography and vessel wall imaging in children with Kawasaki disease

    Energy Technology Data Exchange (ETDEWEB)

    Greil, Gerald F.; Hofbeck, Michael; Sieverding, Ludger [University of Tuebingen, Department of Pediatric Cardiology, Children' s Hospital, Tuebingen (Germany); Seeger, Achim; Miller, Stephan; Claussen, Claus D. [University of Tuebingen, Department of Diagnostic Radiology, Tuebingen (Germany); Botnar, Rene M. [Technical University Munich, Department of Nuclear Medicine, Cardiovascular Division, Munich (Germany)

    2007-07-15

    In patients with Kawasaki disease (KD) serial evaluation of the distribution and size of coronary artery aneurysms (CAA) is necessary for risk stratification and therapeutic management. To apply whole-heart coronary MR angiography (CMRA) and black-blood coronary vessel wall imaging in children with KD. Six children (mean age 4.6 years, range 2.5-7.8 years) with KD underwent CMRA using a free-breathing, T2-prepared, three-dimensional steady-state free-precession (3D-SSFP), whole-heart approach with navigator gating and tracking. Vessel walls were imaged with an ECG-triggered and navigator-gated double inversion recovery (DIR) black-blood segmented turbo spin-echo sequence. There was complete agreement between CMRA and conventional angiography (n=6) in the detection of CAA (n=15). Excellent agreement was found between the two techniques in determining the maximal diameter (mean difference 0.2{+-}0.7 mm), length (mean difference 0.1{+-}0.8 mm) and distance from the ostium (mean difference -0.8{+-}2.1 mm) of the CAAs. In all subjects with a CAA, abnormally thickened vessel walls were found (2.5{+-}0.5 mm). CMRA accurately defines CAA in free-breathing sedated children with KD using the whole-heart approach and detects abnormally thickened vessel walls. This technique may reduce the need for serial X-ray coronary angiography, and improve risk stratification and monitoring of therapy. (orig.)

  10. Model Construct Based Enterprise Model Architecture and Its Modeling Approach

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In order to support enterprise integration, a kind of model construct based enterprise model architecture and its modeling approach are studied in this paper. First, the structural makeup and internal relationships of enterprise model architecture are discussed. Then, the concept of reusable model construct (MC) which belongs to the control view and can help to derive other views is proposed. The modeling approach based on model construct consists of three steps, reference model architecture synthesis, enterprise model customization, system design and implementation. According to MC based modeling approach a case study with the background of one-kind-product machinery manufacturing enterprises is illustrated. It is shown that proposal model construct based enterprise model architecture and modeling approach are practical and efficient.

  11. A New Detection Approach Based on the Maximum Entropy Model

    Institute of Scientific and Technical Information of China (English)

    DONG Xiaomei; XIANG Guang; YU Ge; LI Xiaohua

    2006-01-01

    The maximum entropy model was introduced and a new intrusion detection approach based on the maximum entropy model was proposed. The vector space model was adopted for data presentation. The minimal entropy partitioning method was utilized for attribute discretization. Experiments on the KDD CUP 1999 standard data set were designed and the experimental results were shown. The receiver operating characteristic(ROC) curve analysis approach was utilized to analyze the experimental results. The analysis results show that the proposed approach is comparable to those based on support vector machine(SVM) and outperforms those based on C4.5 and Naive Bayes classifiers. According to the overall evaluation result, the proposed approach is a little better than those based on SVM.

  12. Patient radiation dose from computed tomography angiography and digital subtraction angiography of the brain

    Science.gov (United States)

    Netwong, Y.; Krisanachinda, A.

    2016-03-01

    The 64-row multidetector computed tomography angiography (64-MDCTA) provides vascular image quality of the brain similar to digital subtraction angiography (DSA), but the effective dose of CTA is lower than DSA studied in phantom. The purpose of this study is to evaluate the effective dose from 64-MDCTA and DSA. Effective dose (according to ICRP 103) from 64-MDCTA and DSA flat panel detector for cerebral vessels examination of the brain using standard protocols as recommended by the manufacturer was calculated for 30 cases of MDCTA (15 male and 15 female).The mean patient age was 49.5 (23-89) yrs. 30 cases of DSA (14 male and 16 female), the mean patient age was 46.8 (21-81) yrs. For CTA, the mean effective dose was 3.7 (2.82- 5.19) mSv. For DSA, the mean effective dose was 5.78 (3.3-10.06) mSv. The effective dose of CTA depends on the scanning protocol and scan length. Low tube current can reduce patient dose whereas the number of exposures and number of series in 3D rotational angiography (3D RA) resulted in increasing effective dose in DSA patients.

  13. Multislice CT angiography of interrupted aortic arch

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Dong Hyun; Goo, Hyun Woo [Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea); Seo, Dong-Man; Yun, Tae-Jin; Park, Jeong-Jun [Asan Medical Center, University of Ulsan College of Medicine, Department of Paediatric Cardiac Surgery, Seoul (Korea); Park, In-Sook; Ko, Jae Kon; Kim, Young Hwee [Asan Medical Center, University of Ulsan College of Medicine, Department of Paediatric Cardiology, Seoul (Korea)

    2008-01-15

    Interrupted aortic arch (IAA) is defined as complete luminal and anatomic discontinuity between the ascending and descending aorta. Because almost all patients with IAA become critically ill during the neonatal period, they should undergo urgent corrective surgery. This clinical urgency necessitates a fast and accurate noninvasive diagnostic method. Although echocardiography remains the primary imaging tool for this purpose, it is not always sufficient for planning surgical correction of IAA, principally due to a limited acoustic window and the inexperience of imagers. In this context, multislice CT angiography is regarded as an appropriate imaging technique complementary to echocardiography because it is fast, accurate, and objective for the diagnosis of IAA. In this article we describe what cardiac radiologists should know about IAA in their clinical practice, including clinicopathological features, CT features with contemporary surgical methods and postoperative complications, and differentiation from coarctation of the aorta and aortic arch atresia. (orig.)

  14. Radial pseudoaneurysm following diagnostic coronary angiography

    Directory of Open Access Journals (Sweden)

    Shankar Laudari

    2015-06-01

    Full Text Available The radial artery access has gained popularity as a method of diagnostic coronary catheterization compared to femoral artery puncture in terms of vascular complications and early ambulation. However, very rare complication like radial artery pseudoaneurysm may occur following cardiac catheterization which may give rise to serious consequences. Here, we report a patient with radial pseudoaneurysm following diagnostic coronary angiography. Adequate and correct methodology of compression of radial artery following puncture for maintaining hemostasis is the key to prevention.DOI: http://dx.doi.org/10.3126/jcmsn.v10i3.12776 Journal of College of Medical Sciences-Nepal, 2014, Vol-10, No-3, 48-50

  15. Evaluating a Focus-Based Approach to Anaphora Resolution

    CERN Document Server

    Azzam, S; Gaizauskas, R J; Azzam, Saliha; Humphreys, Kevin; Gaizauskas, Robert

    1998-01-01

    We present an approach to anaphora resolution based on a focusing algorithm, and implemented within an existing MUC (Message Understanding Conference) Information Extraction system, allowing quantitative evaluation against a substantial corpus of annotated real-world texts. Extensions to the basic focusing mechanism can be easily tested, resulting in refinements to the mechanism and resolution rules. Results are compared with the results of a simpler heuristic-based approach.

  16. An ecosystem-based fisheries assessment and forecasting approach

    OpenAIRE

    Zhang, Chang Ik

    2009-01-01

    A comprehensive ecosystem-based approach is required to holistically assess, forecast and manage fisheries resources and their associated habitats by considering ecological interactions of target species with predators, competitors, and prey species, interactions between fishes and their habitats, and the effects of fishing on these processes. A pragmatic ecosystem-based approach was developed for the assessment of fisheries resources involving three management objectives: sustainability, bio...

  17. Self-Optical Coherence Tomography and Angiography

    Directory of Open Access Journals (Sweden)

    Ahmad M. Mansour

    2017-02-01

    Full Text Available Purpose: To present a new concept of self-optical coherence tomography (OCT and self-OCT angiography. Methods: The operator sits in the patient seat and manipulates the instrument body via the joystick with the dominant hand, while the dominant index is ready to press the capture button and while focusing on the fixation target. One senior ophthalmologist judged various OCT machines for ease of self-scan during a major ophthalmic convention. Separately, self-scans were also captured using a single OCT machine by one senior ophthalmologist and 5 junior optometrists and the scans were analyzed for both centration and image quality value (IQV, and compared to regular scans done by an operator. Results: Ten available OCT machines were tested for their ability to allow self-OCT. Machines that had one or more features of auto-alignment, auto-focus, and auto-shoot were ideal for self-OCT or self-OCT angiography. Self-scans done by the ophthalmologist (total 27 scans of right eye, mean IQV = 32.6, and 24 left eyes, mean IQV = 37.3, done over 9 months and 5 optometrists (total 24 scans, mean 34.8 done in one session were comparable to scans (total 11, mean IQV = 38.1 done by an operator for image quality. Decentration was very common in self-scans of the macula (37% right eye and 46% left eye versus 0% for scans of the right eye done by an operator. Conclusions: Self-OCT scans of the macular region can be done with good image quality but are often decentered. Advantages include privacy, potential use by ophthalmic health professionals, airspace station officers, and possible future home self-imaging of macula.

  18. Multidetector CT angiography in Takayasu arteritis

    Energy Technology Data Exchange (ETDEWEB)

    Khandelwal, Niranjan; Kalra, Naveen [Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, Chandigarh 160012 (India); Garg, Mandeep Kumar, E-mail: gargmandeep@hotmail.com [Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, Chandigarh 160012 (India); Kang, Mandeep; Lal, Anupam [Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, Chandigarh 160012 (India); Jain, Sanjay [Department of Internal Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh 160012 (India); Suri, Sudha [Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, Chandigarh 160012 (India)

    2011-02-15

    Objective: To analyse the spectrum of Takayasu's arteritis (TA) on multidetector CT angiography (MDCTA). Materials and methods: A retrospective analysis of the MDCTA findings was performed on 15 patients clinically diagnosed as Takayasu's arteritis. The spectrum and incidence of imaging findings on CTA were compared to studies in literature on catheter angiography in Takayasu's arteritis. Laboratory parameters were available in nine patients. The disease was considered active if erythrocyte sedimentation rate (ESR) levels were elevated and 'C' reactive protein (CRP) was positive. An attempt was made to correlate disease activity with the imaging findings. Results: Ascending aorta, arch of aorta and descending thoracic aorta were involved in 14 out of 15 (93%) patients. The wall thickness varied between 1 and 10 mm with maximal involvement in arch and descending thoracic aorta. Major neck vessels were involved in 11 (73%) patients with most pronounced changes seen in the brachiocephalic trunk, left common carotid artery (CCA) and left subclavian artery (SCA). Abdominal aorta and its branches were involved in all the 11 (100%) patients in whom abdominal CTA was performed. Celiac axis and SMA were involved in 10 (91%) and seven (64%) patients, respectively while renal artery stenosis was present in five (45%) patients. In six patients, ESR was elevated and CRP was positive indicating active disease. All patients in whom the laboratory parameters were available showed mural thickening in the aorta and at least one of the neck vessels except for one patient with inactive disease who had aortic mural thickening only. Conclusion: MDCTA provides information about both the vessel wall and lumen in patients with Takayasu's disease.

  19. Digital subtraction angiography of the cerebral vessels by intraarterial injection

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Izumi; Kikuchi, Haruhiko; Karasawa, Jun; Mitsugi, Toru; Naruo, Yoshito; Takamiya, Makoto (National Cardiovascular Center, Suita, Osaka (Japan))

    1984-10-01

    Three hundred and fifty-seven digital subtraction angiography (DSA) were performed in 184 neurosurgical patients by intraarterial injection. Examinations consisted of 192 carotid angiography, 110 vertebral angiography, 23 aortography, 11 spinal angiography and 21 other angiography. In all examinations, visualization of the vessels was excellent and the complications were never experienced. High contrast sensitivity of DSA resulted in better visualization of tumor stains, phlebogram, and arteries in cerebral arteriovenous malformations with large shunt blood flow than conventional angiography. Selective catheterization into each cerebral arteries was not necessarily demanded for good opacification of the vessels because of high sensitivity. High contrast sensitivity also permitted low concentration of contrast material, small dose of contrast material, and slow injection rate. Low concentration of contrast material reduced pain and heat during injection especially in the external carotid and vertebral angiography. Using slow injection, recoiling of catheter into the aorta was reduced, so that injection from the innominate and subclavian arteries for visualization of origin of the cerebral arteries were always successful. Full study of cerebral arteries by Seldinger's method, if necessary, was easily achieved using DSA even in patient with high age or with severe atherosclerosis. Bolus injection of small dose of contrast material as well as serial imaging was helpful in evaluating hemodynamics in the lesion. Real time display of DSA reduced the time required for angiography and was very convenient for artificial embolization. Besides these advantages, DSA became comparable to conventional angiography in spacial resolution by use of intraarterial injection and could be a preoperative genuine examination as well as a screening method.

  20. A Programmable Approach to Maintenance of a Finite Knowledge Base

    Institute of Scientific and Technical Information of China (English)

    LUAN ShangMin(栾尚敏); DAI GuoZhong(戴国忠); LI Wei(李未)

    2003-01-01

    In this paper, we present a programmable method of revising a finite clause set. We first present a procedure whose formal parameters are a consistent clause set Γ and a clause A and whose output is a set of minimal subsets of Γ which are inconsistent with A. The maximal consistent subsets can be generated from all minimal inconsistent subsets. We develop a prototype system based on the above procedure, and discuss the implementation of knowledge base maintenance. At last, we compare the approach presented in this paper with other related approaches. The main characteristic of the approach is that it can be implemented by a computer program.

  1. Isolated retinal cotton wool spot after coronary angiography

    Science.gov (United States)

    Kopsachilis, Nikolaos; Brar, Manpreet; Marinescu, Anca I. C.; Sivaprasad, Sobha

    2013-01-01

    Visual symptoms after coronary angiography are rarely encountered and mostly related to contrast induced transient cortical blindness or retinal artery occlusions. We report an intriguing case of a 50-year-old woman, who presented with vision deterioration in her right eye 12 h after coronary angiography for cardiac palpitation. Fundoscopy and optical coherence tomography scan revealed an isolated parafoveal cotton wool spot in her right eye that has totally resolved 6 weeks after initial presentation. This is the first case report of this rare post coronary angiography complication. PMID:23772127

  2. Transient cortical blindness following vertebral angiography: a case report.

    Science.gov (United States)

    Lo, Lai Wan; Chan, Ho Fung; Ma, Ka Fai; Cheng, Lik Fai; Chan, Tony Kt

    2015-02-01

    Transient cortical blindness (TCB) is a rare but well-known complication of cerebral angiography. Its pathophysiology remains uncertain. We would like to report a case of TCB in a patient during a follow up vertebral angiogram for post-coil embolization of left posterior inferior cerebellar artery aneurysm. Patient's vision was resumed spontaneously within 24 hours after angiography, with no residual neurological deficit in subsequent clinical follow up. Multi-modality imaging evaluation including vertebral angiography, brain CT and MRI performed on same day are presented.

  3. Isolated retinal cotton wool spot after coronary angiography

    Directory of Open Access Journals (Sweden)

    Nikolaos Kopsachilis

    2013-01-01

    Full Text Available Visual symptoms after coronary angiography are rarely encountered and mostly related to contrast induced transient cortical blindness or retinal artery occlusions. We report an intriguing case of a 50-year-old woman, who presented with vision deterioration in her right eye 12 h after coronary angiography for cardiac palpitation. Fundoscopy and optical coherence tomography scan revealed an isolated parafoveal cotton wool spot in her right eye that has totally resolved 6 weeks after initial presentation. This is the first case report of this rare post coronary angiography complication.

  4. Content-based, Task-based, and Participatory Approaches (II)

    Institute of Scientific and Technical Information of China (English)

    Diane Larsen-Freeman

    2012-01-01

    4. Participatory Approach Although it originated in the early sixties with the work of Paulo Freire, and therefore antedates modern versions of content-based and task-based approaches, it was not until the 1980s that the participatory approach started being widely discussed in the language teaching literature.

  5. Integrating Ontological Data Sources Using Viewpoints-Based Approach

    Directory of Open Access Journals (Sweden)

    Bouchra Boulkroun

    2016-12-01

    Full Text Available Within the development of Internet and intranets, information integration from various data sources becomes increasingly important and more challenging issue. Recently, the trend in data integration has favored the semantic integration using ontologies. However, the existing ontology-based approaches do not support the aspect of data multi-representations, which is important in the development of multi-user applications. The motivation of this paper is to address a novel semantic integration approach based on ontologies and viewpoints paradigms. This contribution combines the advantages of existing ontology-based integration approaches while avoiding their drawbacks. The proposed integration approach is evaluated using query processing. Profiles are introduced to offer answers to users according to their viewpoints and choices.

  6. Local fractal dimension based approaches for colonic polyp classification.

    Science.gov (United States)

    Häfner, Michael; Tamaki, Toru; Tanaka, Shinji; Uhl, Andreas; Wimmer, Georg; Yoshida, Shigeto

    2015-12-01

    This work introduces texture analysis methods that are based on computing the local fractal dimension (LFD; or also called the local density function) and applies them for colonic polyp classification. The methods are tested on 8 HD-endoscopic image databases, where each database is acquired using different imaging modalities (Pentax's i-Scan technology combined with or without staining the mucosa) and on a zoom-endoscopic image database using narrow band imaging. In this paper, we present three novel extensions to a LFD based approach. These extensions additionally extract shape and/or gradient information of the image to enhance the discriminativity of the original approach. To compare the results of the LFD based approaches with the results of other approaches, five state of the art approaches for colonic polyp classification are applied to the employed databases. Experiments show that LFD based approaches are well suited for colonic polyp classification, especially the three proposed extensions. The three proposed extensions are the best performing methods or at least among the best performing methods for each of the employed databases. The methods are additionally tested by means of a public texture image database, the UIUCtex database. With this database, the viewpoint invariance of the methods is assessed, an important features for the employed endoscopic image databases. Results imply that most of the LFD based methods are more viewpoint invariant than the other methods. However, the shape, size and orientation adapted LFD approaches (which are especially designed to enhance the viewpoint invariance) are in general not more viewpoint invariant than the other LFD based approaches.

  7. A Comparison of Filter-based Approaches for Model-based Prognostics

    Data.gov (United States)

    National Aeronautics and Space Administration — Model-based prognostics approaches use domain knowledge about a system and its failure modes through the use of physics-based models. Model-based prognosis is...

  8. Rotational micro-CT using a clinical C-arm angiography gantry

    Energy Technology Data Exchange (ETDEWEB)

    Patel, V.; Hoffmann, K. R.; Ionita, C. N.; Keleshis, C.; Bednarek, D. R.; Rudin, S. [Toshiba Stroke Research Center, Department of Physics, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Neurosurgery, Department of Physics, Department of Physiology and Biophysics, Department of Mechanical and Aerospace Engineering, and Department of Computer Science, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Neurosurgery, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Electrical Engineering, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Radiology, Department of Neurosurgery, Department of Physics, and Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Radiology, Department of Neurosurgery, Department of Physiology and Biophysics, Department of Mechanical and Aerospace Engineering, and Department of Electrical Engineering, State University of New York at Buffalo, Buffalo, New York 14214 (United States)

    2008-10-15

    Rotational angiography (RA) gantries are used routinely to acquire sequences of projection images of patients from which 3D renderings of vascular structures are generated using Feldkamp cone-beam reconstruction algorithms. However, these systems have limited resolution (<4 lp/mm). Micro-computed tomography (micro-CT) systems have better resolution (>10 lp/mm) but to date have relied either on rotating object imaging or small bore geometry for small animal imaging, and thus are not used for clinical imaging. The authors report here the development and use of a 3D rotational micro-angiography (RMA) system created by mounting a micro-angiographic fluoroscope (MAF) [35 {mu}m pixel, resolution >10 lp/mm, field of view (FOV)=3.6 cm] on a standard clinical FPD-based RA gantry (Infinix, Model RTP12303J-G9E, Toshiba Medical Systems Corp., Tustin, CA). RA image sequences are obtained using the MAF and reconstructed. To eliminate artifacts due to image truncation, lower-dose (compared to MAF acquisition) full-FOV (FFOV) FPD RA sequences (194 {mu}m pixel, FOV=20 cm) were also obtained to complete the missing data. The RA gantry was calibrated using a helical bead phantom. To ensure high-quality high-resolution reconstruction, the high-resolution images from the MAF were aligned spatially with the lower-dose FPD images, and the pixel values in the FPD image data were scaled to match those of the MAF. Images of a rabbit with a coronary stent placed in an artery in the Circle of Willis were obtained and reconstructed. The MAF images appear well aligned with the FPD images (average correlation coefficient before and after alignment: 0.65 and 0.97, respectively) Greater details without any visible truncation artifacts are seen in 3D RMA (MAF-FPD) images than in those of the FPD alone. The FWHM of line profiles of stent struts (100 {mu}m diameter) are approximately 192{+-}21 and 313{+-}38 {mu}m for the 3D RMA and FPD data, respectively. In addition, for the dual-acquisition 3D RMA

  9. Knowledge-based biomedical word sense disambiguation: comparison of approaches

    Directory of Open Access Journals (Sweden)

    Aronson Alan R

    2010-11-01

    Full Text Available Abstract Background Word sense disambiguation (WSD algorithms attempt to select the proper sense of ambiguous terms in text. Resources like the UMLS provide a reference thesaurus to be used to annotate the biomedical literature. Statistical learning approaches have produced good results, but the size of the UMLS makes the production of training data infeasible to cover all the domain. Methods We present research on existing WSD approaches based on knowledge bases, which complement the studies performed on statistical learning. We compare four approaches which rely on the UMLS Metathesaurus as the source of knowledge. The first approach compares the overlap of the context of the ambiguous word to the candidate senses based on a representation built out of the definitions, synonyms and related terms. The second approach collects training data for each of the candidate senses to perform WSD based on queries built using monosemous synonyms and related terms. These queries are used to retrieve MEDLINE citations. Then, a machine learning approach is trained on this corpus. The third approach is a graph-based method which exploits the structure of the Metathesaurus network of relations to perform unsupervised WSD. This approach ranks nodes in the graph according to their relative structural importance. The last approach uses the semantic types assigned to the concepts in the Metathesaurus to perform WSD. The context of the ambiguous word and semantic types of the candidate concepts are mapped to Journal Descriptors. These mappings are compared to decide among the candidate concepts. Results are provided estimating accuracy of the different methods on the WSD test collection available from the NLM. Conclusions We have found that the last approach achieves better results compared to the other methods. The graph-based approach, using the structure of the Metathesaurus network to estimate the relevance of the Metathesaurus concepts, does not perform well

  10. Integration of Task-Based Approaches in a TESOL Course

    Science.gov (United States)

    Chien, Chin-Wen

    2014-01-01

    Under task-based language teaching (TBLT), language learners engage in purposeful, problem-oriented, and outcome-driven tasks that are comparable to real-world activities. This qualitative case study discusses the integration of a task-based approach into a TESOL course in a language teacher education program in Taiwan with regard to 39…

  11. Assessing a New Approach to Class-Based Affirmative Action

    Science.gov (United States)

    Gaertner, Matthew N.

    2011-01-01

    In November, 2008, Colorado and Nebraska voted on amendments that sought to end race-based affirmative action at public universities. In anticipation of the vote, Colorado's flagship public institution--The University of Colorado at Boulder (CU)--explored statistical approaches to support class-based affirmative action. This paper details CU's…

  12. A SEMINAR-DISCUSSION-BASED APPROACH TOWARD LINGUISTICS

    Institute of Scientific and Technical Information of China (English)

    郎勇

    2002-01-01

    In this article, based on the experience of many years of teaching Linguistics courses to undergraduates, postgraduates and in-service teacher trainees, we argue that taking a seminar-discussion-based approach is a better way to achieve students' full involvement and understanding.

  13. Evaluation of the pedal artery: comparison of three-dimensional gadolinium-enhanced MR angiography with digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Min; Kang, Sung Gwon; Byun, Joo Nam; Kim, Young Cheol; Choi, Jeong Yeol; Kim, Dong Hyun [College of Medicine, Chosun Univ., Kwangju (Korea, Republic of)

    2002-07-01

    To compare the three-dimensional gadolinium-enhanced MR angiography with digital subtraction angiography (DSA) for evaluation of the pedal artery. In 12 extremities of 11 patients, both digital subtraction angiography (DSA) and contrast-enhanced MR angiography (CE-MR angiography) were performed during the same week. Among ten of the 11 patients, the following conditions were present: atherosclerosis (n=4), diabetic foot (n=3), Buerger's disease (n=1), calciphylactic arteriopathy (n=1) and arteriovenous malformation of the foot (n=1). The remaining patient underwent angiography prior to flap surgery. For MR angiography, a 1.5T system using an extremity or head coil was used. A three-dimensional FISP (fast imaging with steady state precession) sequence was obtained before enhancement, followed by four sequential acquisitions (scan time, 20 secs, scan interval time, 10 secs) 10 seconds after intravenous bolus injection of normal saline (total 10 cc), following intravenous administration of gadolinium (0.02 mmol/kg, 3 ml/sec). Arterial segments of the ankle and foot were classified as the anterior or posterior tibial artery, the distal peroneal artery, the medial or lateral plantar artery, the pedal arch, and the dorsalis pedis artery. Two radiologists independently analysed visualization of each arteraial segment and the mean of visible arterial segments in one extreminty using CE-MR angiography and DSA. Among 84 arterial segments, 16 were invisible at both CE-MR angiography and DSA, while 39 were demonstrated by both modalities. Twenty-six segments were visible only at CE-MR angiography and three only at DSA. CE-MR angiography displayed a higher number of arterial segments than DSA (mean, 5.42 vs. mean 3.50, respectively), a difference which was statistically significant (p<0.000). The difference between each arterial segment was not statistically significant, except for the dorsalis pedis artery (t test, p<0.000). In that it provides additional information for

  14. System identification based approach to dynamic weighing revisited

    Science.gov (United States)

    Niedźwiecki, Maciej; Meller, Michał; Pietrzak, Przemysław

    2016-12-01

    Dynamic weighing, i.e., weighing of objects in motion, without stopping them on the weighing platform, allows one to increase the rate of operation of automatic weighing systems, used in industrial production processes, without compromising their accuracy. Since the classical identification-based approach to dynamic weighing, based on the second-order mass-spring-damper model of the weighing system, does not yield satisfactory results when applied to conveyor belt type checkweighers, several extensions of this technique are examined. Experiments confirm that when appropriately modified the identification-based approach becomes a reliable tool for dynamic mass measurement in checkweighers.

  15. Intravenous coronary angiography using electron beam computed tomography

    NARCIS (Netherlands)

    Rensing, B J; Bongaerts, A H; van Geuns, R J; van Ooijen, P M; Oudkerk, M; de Feyter, P J

    1999-01-01

    Intravenous coronary angiography with electron beam computed tomography (EBCT) allows for the noninvasive visualisation of coronary arteries. With dedicated computer hardware and software, three-dimensional renderings of the coronary arteries, veins, and other cardiac structures can be constructed f

  16. A Brief Introduction of Task-based Approach

    Institute of Scientific and Technical Information of China (English)

    王丹

    2012-01-01

    The task-based language teaching approach is one of the syllabus models that have been proposed in the last twenty years or so. Task-based syllabus represent a particular realization of communicative language teaching. Task-based teaching/learning helps develop students’ communicative competence, enabling them to communicate effectively in real communicating world and engage in interaction. The most active element in the process of the task-based teaching is the learner’ creativity. By exploiting this kind of creativity, learning can be made significantly more efficient and more interesting. It is well-known that the task-based teaching/learning have a rich potential for promoting successful second language learning than the traditional teaching/learning. Task-based approach is reflected not only in China but also in some other countries, such as America, Canada, Singapore, Hong Kong and son on.

  17. An Integrated Approach for Creating Service-Based Interactive Applications

    Science.gov (United States)

    Feldmann, Marius; Janeiro, Jordan; Nestler, Tobias; Hübsch, Gerald; Jugel, Uwe; Preussner, André; Schill, Alexander

    While the implementation of business logic and business processes based on service-oriented architectures is well-understood and covered by existing development approaches, integrated concepts that empower users to exploit the Internet of Services to create complex interactive applications are missing. In this paper, we present an integrated approach that fills this gap. Our approach builds upon service annotations that add meta-information related to user interface generation, service dependencies, and service composition to existing service descriptions. Services can be composed visually to complex interactive applications based on these annotations without the need to write any code. The application code is generated completely from the service composition description. Our approach is able to support heterogeneous target environments ranging from client/server architectures to mobile platforms.

  18. Analysis of Kernel Approach in Fuzzy-Based Image Classifications

    Directory of Open Access Journals (Sweden)

    Mragank Singhal

    2013-03-01

    Full Text Available This paper presents a framework of kernel approach in the field of fuzzy based image classification in remote sensing. The goal of image classification is to separate images according to their visual content into two or more disjoint classes. Fuzzy logic is relatively young theory. Major advantage of this theory is that it allows the natural description, in linguistic terms, of problems that should be solved rather than in terms of relationships between precise numerical values. This paper describes how remote sensing data with uncertainty are handled with fuzzy based classification using Kernel approach for land use/land cover maps generation. The introduction to fuzzification using Kernel approach provides the basis for the development of more robust approaches to the remote sensing classification problem. The kernel explicitly defines a similarity measure between two samples and implicitly represents the mapping of the input space to the feature space.

  19. Digital subtraction angiography in pediatric cerebrovascular occlusive disease

    Energy Technology Data Exchange (ETDEWEB)

    Faerber, E.N.; Griska, L.A.B.; Swartz, J.D.; Capitanio, M.A.; Popky, G.L.

    1984-08-01

    While conventional angiography has been used to demonstrate cerebrovascular occlusive disease in the past, digital subtraction angiography (DSA) is capable of showing progressive vascular involvement with ease, simplicity, and extremely low morbidity, making it particularly well suited for children and outpatients either alone or coordinated with computed tomography. The authors discuss the usefulness and advantages of DSA as demonstrated in 7 infants and children with hemiplegia, 4 of whom had sickle-cell disease.

  20. A Moving Human Tracking Approach Based on Semantic Interaction

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ning; FANG Bao-hong; SUN Fu-liang

    2007-01-01

    In order to deal with partical occlusion, a semantic interaction based moving human tracking approach is put forward. Firstly human is modeled as moving blobs which are described as blob descriptions. Then moving blobs are updated and verified by projecting these descriptions. The approach exploits improved fast gauss transform and chooses source and target samples to reduce compute cost. Multi-moving human can be tracked simply and part occlusion can be done well.

  1. An Eavesdropping Detecting Approach Based on Mode-Mode Correlation

    Institute of Scientific and Technical Information of China (English)

    XIONG Jin; ZENG Gui-Hua; ZHOU Nan-Run

    2005-01-01

    @@ We find that second-order coherence as well as a Hanbury-Brown-Twiss intensity interferometer may provide an optimal approach for eavesdropping detection in the quantum key distribution based on two-mode squeezed'vacuum states. With this approach, eavesdropping can be easily detected without sacrificing extra secret bits as the test key. In addition, the efficiency of the quantum key distribution protocol is enhanced greatly.

  2. LMI Approach to Observer-based FD Systems Designing

    Institute of Scientific and Technical Information of China (English)

    钟麦英; 汤兵勇; 丁·史蒂芬·先春

    2001-01-01

    Increasing the robustness to the unknown uncertainty and simultaneously enhancing the sensibility to the faults is one of the important issues considered in the fault detection development. Considering the L2-gain of residual system, this paper deals the observer-based fault detection problem. By using of H∞ control theory,an LMI approach to design fault detection observer is given. A numerical example is used to illustrate the effectiveness of the proposed approach.

  3. RESEARCH ON NEGOTIATION-BASED PARTNER SELECTION APPROACH

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The key problem in the construction of virtual enterprises (VEs) is how to select appropriate partners. The negotiation-based approach is proposed to support partner selection in the construction of VEs . The negotiation model is discussed from three main aspects respectively, i.e., negotiation protocol, negotiation goal and negotiation decision-making model. And the generic mathematical description of the negotiation model is formally presented. Finally, a simple example is used to validate the approach's availability.

  4. Diagnosing intracranial vasculitis: The roles of MR and angiography

    Energy Technology Data Exchange (ETDEWEB)

    Harris, K.G.; Tran, D.D.; Sickels, W.J.; Cornell, S.H.; Yuh, W.T.C. (Univ. of Iowa College of Medicine, Iowa City, IA (United States))

    1994-02-01

    To describe our experience with MR and angiography in diagnosing intracranial vasculitis and to test the hypothesis that MR can be used to screen for patients unlikely to have vasculitis. Ninety-two patients who had angiography with [open quotes]exclude vasculitis[close quotes] as the indication or who had angiography and a clinical diagnosis of vasculitis were identified. Angiograms of all 92 patients and the MRs of the 70 patients who had both studies were reviewed. Eleven patients had intracranial vasculitis. Angiography showed characteristic changes in 8. MR performed in 9 of 11 vasculitis cases, was significantly abnormal in all 9. Among 70 patients who had both studies, 19 had MR that was completely normal or showed only incidental findings. None of these 19 was diagnosed with vasculitis. The diagnostic yield of angiography performed to exclude vasculitis was only 6%. Evaluation for intracranial vasculitis should include MR. A negative MR excludes intracranial vasculitis more definitively than does a negative angiogram and makes the likelihood of finding vasculitis with angiography negligible. 23 refs., 5 figs., 4 tabs.

  5. The role of CT angiography in the evaluation of pediatric renovascular hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Kurian, Jessica [The Perelman School of Medicine, University of Pennsylvania, Department of Radiology, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States); The Children' s Hospital at Montefiore, Bronx, NY (United States); Epelman, Monica [The Perelman School of Medicine, University of Pennsylvania, Department of Radiology, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States); Nemours Children' s Hospital, Department of Radiology, Orlando, FL (United States); Darge, Kassa; Nijs, Els [The Perelman School of Medicine, University of Pennsylvania, Department of Radiology, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States); Meyers, Kevin [The Perelman School of Medicine, University of Pennsylvania, Division of Nephrology, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States); Hellinger, Jeffrey C. [The Perelman School of Medicine, University of Pennsylvania, Department of Radiology, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States); New York Cardiovascular Institute and Lenox Hill Radiology, New York, NY (United States)

    2013-04-15

    Historically, the evaluation of renovascular hypertension has been accomplished by US, renal scintigraphy and digital subtraction angiography. Based on its high accuracy reported in adults renal CT angiography (CTA) with pediatric-appropriate low radiation dose techniques has become an important tool in the workup of renovascular hypertension in children. Renal CTA has several advantages over more conventional imaging modalities, including rapid and non-invasive acquisition, high resolution and easy reproducibility. Additionally, in our experience high-quality renal CTA can be performed using low-dose radiation exposures and can be acquired without sedation in most instances. This article illustrates by examples the usefulness of renal CTA for diagnosis of childhood renovascular hypertension and provides an overview of renal CTA findings in the most common childhood renovascular diseases. (orig.)

  6. CT angiography versus 3D rotational angiography in patients with subarachnoid hemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Bechan, R.S.; Peluso, J.P.; Sluzewski, M.; Rooij, W.J. van [Sint Elisabeth Ziekenhuis Tilburg, Department of Radiology, Tilburg (Netherlands); Rooij, S.B. van [Medisch Centrum Alkmaar, Department of Radiology, Alkmaar (Netherlands); Sprengers, M.E.; Majoie, C.B. [Academisch Medisch Centrum, Department of Radiology, Amsterdam (Netherlands)

    2015-12-15

    CT angiography (CTA) is increasingly used as primary diagnostic tool to replace digital subtraction angiography (DSA) in patients with subarachnoid hemorrhage (SAH). However, 3D rotational angiography (3DRA) has substituted DSA as a reference standard. In this prospective observational study, we compare CTA with 3DRA of all cerebral vessels in a large cohort of patients with SAH. Of 179 consecutive patients with SAH admitted between March 2013 and July 2014, 139 underwent 64- to 256-detector row CTA followed by complete cerebral 3DRA within 24 h. In 86 patients (62 %), 3DRA was performed under general anesthesia. Two observers from outside hospitals reviewed CTA data. In 118 of 139 patients (85 %), 3DRA diagnosed the cause of hemorrhage: 113 ruptured aneurysms, three arterial dissections, one micro-arteriovenous malformation (AVM), and one reversible vasoconstriction syndrome. On CTA, both observers missed all five non-aneurysmal causes of SAH. Sensitivity of CTA in depicting ruptured aneurysms was 0.88-0.91, and accuracy was 0.88-0.92. Of 113 ruptured aneurysms, 28 were ≤3 mm (25 %) and of 95 additional aneurysms, 71 were ≤3 mm (75 %). Sensitivity of depicting aneurysms ≤3 mm was 0.28-0.43. Of 95 additional aneurysms, the two raters missed 65 (68 %) and 58 (61 %). Sensitivity in detection was lower in aneurysms of the internal carotid artery than in other locations. CTA had some limitations as primary diagnostic tool in patients with SAH. All non-aneurysmal causes for SAH and one in ten ruptured aneurysms were missed. Performance of CTA was poor in aneurysms ≤3 mm. The majority of additional aneurysms were not depicted on CTA. (orig.)

  7. A discrete Lagrangian based direct approach to macroscopic modelling

    Science.gov (United States)

    Sarkar, Saikat; Nowruzpour, Mohsen; Reddy, J. N.; Srinivasa, A. R.

    2017-01-01

    A direct discrete Lagrangian based approach, designed at a length scale of interest, to characterize the response of a body is proposed. The main idea is to understand the dynamics of a deformable body via a Lagrangian corresponding to a coupled interaction of rigid particles in the reduced dimension. We argue that the usual practice of describing the laws of a deformable body in the continuum limit is redundant, because for most of the practical problems, analytical solutions are not available. Since continuum limit is not taken, the framework automatically relaxes the requirement of differentiability of field variables. The discrete Lagrangian based approach is illustrated by deriving an equivalent of the Euler-Bernoulli beam model. A few test examples are solved, which demonstrate that the derived non-local model predicts lower deflections in comparison to classical Euler-Bernoulli beam solutions. We have also included crack propagation in thin structures for isotropic and anisotropic cases using the Lagrangian based approach.

  8. A Variance Based Active Learning Approach for Named Entity Recognition

    Science.gov (United States)

    Hassanzadeh, Hamed; Keyvanpour, Mohammadreza

    The cost of manually annotating corpora is one of the significant issues in many text based tasks such as text mining, semantic annotation and generally information extraction. Active Learning is an approach that deals with reduction of labeling costs. In this paper we proposed an effective active learning approach based on minimal variance that reduces manual annotation cost by using a small number of manually labeled examples. In our approach we use a confidence measure based on the model's variance that reaches a considerable accuracy for annotating entities. Conditional Random Field (CRF) is chosen as the underlying learning model due to its promising performance in many sequence labeling tasks. The experiments show that the proposed method needs considerably fewer manual labeled samples to produce a desirable result.

  9. An Open Science Approach to Gis-Based Paleoenvironment Data

    Science.gov (United States)

    Willmes, C.; Becker, D.; Verheul, J.; Yener, Y.; Zickel, M.; Bolten, A.; Bubenzer, O.; Bareth, G.

    2016-06-01

    Paleoenvironmental studies and according information (data) are abundantly published and available in the scientific record. However, GIS-based paleoenvironmental information and datasets are comparably rare. Here, we present an Open Science approach for creating GIS-based data and maps of paleoenvironments, and Open Access publishing them in a web based Spatial Data Infrastructure (SDI), for access by the archaeology and paleoenvironment communities. We introduce an approach to gather and create GIS datasets from published non-GIS based facts and information (data), such as analogous maps, textual information or figures in scientific publications. These collected and created geo-datasets and maps are then published, including a Digital Object Identifier (DOI) to facilitate scholarly reuse and citation of the data, in a web based Open Access Research Data Management Infrastructure. The geo-datasets are additionally published in an Open Geospatial Consortium (OGC) standards compliant SDI, and available for GIS integration via OGC Open Web Services (OWS).

  10. User-based and Cognitive Approaches to Knowledge Organization

    DEFF Research Database (Denmark)

    Hjørland, Birger

    2013-01-01

    In the 1970s and 1980s, forms of user-based and cognitive approaches to knowledge organization came to the forefront as part of the overall development in library and information science and in the broader society. The specific nature of userbased approaches is their basis in the empirical studies......’s PageRank are not based on the empirical studies of users. In knowledge organization, the Book House System is one example of a system based on user studies. In cognitive science the important WordNet database is claimed to be based on psychological research. This article considers such examples....... The role of the user is often confused with the role of subjectivity. Knowledge organization systems cannot be objective and must therefore, by implication, be based on some kind of subjectivity. This subjectivity should, however, be derived from collective views in discourse communities rather than...

  11. Mindfulness-based approaches: are they all the same?

    Science.gov (United States)

    Chiesa, Alberto; Malinowski, Peter

    2011-04-01

    Mindfulness-based approaches are increasingly employed as interventions for treating a variety of psychological, psychiatric and physical problems. Such approaches include ancient Buddhist mindfulness meditations such as Vipassana and Zen meditations, modern group-based standardized meditations, such as mindfulness-based stress reduction and mindfulness-based cognitive therapy, and further psychological interventions, such as dialectical behavioral therapy and acceptance and commitment therapy. We review commonalities and differences of these interventions regarding philosophical background, main techniques, aims, outcomes, neurobiology and psychological mechanisms. In sum, the currently applied mindfulness-based interventions show large differences in the way mindfulness is conceptualized and practiced. The decision to consider such practices as unitary or as distinct phenomena will probably influence the direction of future research.

  12. Patients' Views of Cardiac Computed Tomography Angiography Compared With Conventional Coronary Angiography

    DEFF Research Database (Denmark)

    Sandgaard, Niels C F; Diederichsen, Axel Cosmus Pyndt; Petersen, Henrik;

    2012-01-01

    : For comparison of CTA and invasive coronary angiography (CA), a total of 127 patients referred for CA for the suspicion of coronary artery disease were included in the study. Three months later the patients received a simple structured questionnaire addressing their views and preferences with regard to CTA...... versus CA. RESULTS: A total of 122 of 127 patients agreed to participate in the study. Pain or bleeding at the puncture site the day after the procedure was significantly more prevalent after CA than CTA (pain, 53% vs 2%; bleeding, 75% vs 22%). More patients had to stay home from work after CA...

  13. A cloud model-based approach for water quality assessment.

    Science.gov (United States)

    Wang, Dong; Liu, Dengfeng; Ding, Hao; Singh, Vijay P; Wang, Yuankun; Zeng, Xiankui; Wu, Jichun; Wang, Lachun

    2016-07-01

    Water quality assessment entails essentially a multi-criteria decision-making process accounting for qualitative and quantitative uncertainties and their transformation. Considering uncertainties of randomness and fuzziness in water quality evaluation, a cloud model-based assessment approach is proposed. The cognitive cloud model, derived from information science, can realize the transformation between qualitative concept and quantitative data, based on probability and statistics and fuzzy set theory. When applying the cloud model to practical assessment, three technical issues are considered before the development of a complete cloud model-based approach: (1) bilateral boundary formula with nonlinear boundary regression for parameter estimation, (2) hybrid entropy-analytic hierarchy process technique for calculation of weights, and (3) mean of repeated simulations for determining the degree of final certainty. The cloud model-based approach is tested by evaluating the eutrophication status of 12 typical lakes and reservoirs in China and comparing with other four methods, which are Scoring Index method, Variable Fuzzy Sets method, Hybrid Fuzzy and Optimal model, and Neural Networks method. The proposed approach yields information concerning membership for each water quality status which leads to the final status. The approach is found to be representative of other alternative methods and accurate.

  14. A Market-Based Approach to Multi-factory Scheduling

    Science.gov (United States)

    Vytelingum, Perukrishnen; Rogers, Alex; MacBeth, Douglas K.; Dutta, Partha; Stranjak, Armin; Jennings, Nicholas R.

    In this paper, we report on the design of a novel market-based approach for decentralised scheduling across multiple factories. Specifically, because of the limitations of scheduling in a centralised manner - which requires a center to have complete and perfect information for optimality and the truthful revelation of potentially commercially private preferences to that center - we advocate an informationally decentralised approach that is both agile and dynamic. In particular, this work adopts a market-based approach for decentralised scheduling by considering the different stakeholders representing different factories as self-interested, profit-motivated economic agents that trade resources for the scheduling of jobs. The overall schedule of these jobs is then an emergent behaviour of the strategic interaction of these trading agents bidding for resources in a market based on limited information and their own preferences. Using a simple (zero-intelligence) bidding strategy, we empirically demonstrate that our market-based approach achieves a lower bound efficiency of 84%. This represents a trade-off between a reasonable level of efficiency (compared to a centralised approach) and the desirable benefits of a decentralised solution.

  15. Aqueous Angiography: Real-Time and Physiologic Aqueous Humor Outflow Imaging.

    Directory of Open Access Journals (Sweden)

    Sindhu Saraswathy

    Full Text Available Trabecular meshwork (TM bypass surgeries attempt to enhance aqueous humor outflow (AHO to lower intraocular pressure (IOP. While TM bypass results are promising, inconsistent success is seen. One hypothesis for this variability rests upon segmental (non-360 degrees uniform AHO. We describe aqueous angiography as a real-time and physiologic AHO imaging technique in model eyes as a way to simulate live AHO imaging.Pig (n = 46 and human (n = 6 enucleated eyes were obtained, orientated based upon inferior oblique insertion, and pre-perfused with balanced salt solution via a Lewicky AC maintainer through a 1mm side-port. Fluorescein (2.5% was introduced intracamerally at 10 or 30 mm Hg. With an angiographer, infrared and fluorescent (486 nm images were acquired. Image processing allowed for collection of pixel information based on intensity or location for statistical analyses. Concurrent OCT was performed, and fixable fluorescent dextrans were introduced into the eye for histological analysis of angiographically active areas.Aqueous angiography yielded high quality images with segmental patterns (p<0.0001; Kruskal-Wallis test. No single quadrant was consistently identified as the primary quadrant of angiographic signal (p = 0.06-0.86; Kruskal-Wallis test. Regions of high proximal signal did not necessarily correlate with regions of high distal signal. Angiographically positive but not negative areas demonstrated intrascleral lumens on OCT images. Aqueous angiography with fluorescent dextrans led to their trapping in AHO pathways.Aqueous angiography is a real-time and physiologic AHO imaging technique in model eyes.

  16. Wall-to-lumen ratio of intracranial arteries measured by indocyanine green angiography

    Science.gov (United States)

    Nakagawa, Daichi; Shojima, Masaaki; Yoshino, Masanori; Kin, Taichi; Imai, Hideaki; Nomura, Seiji; Saito, Toki; Nakatomi, Hirofumi; Oyama, Hiroshi; Saito, Nobuhito

    2016-01-01

    Background: The wall-to-lumen ratio (WLR) is an important parameter in vascular medicine because it indicates the character of vascular wall as well as the degree of stenosis. Despite the advances in medical imaging technologies, it is still difficult to measure the thin-walled normal intracranial arteries, and the reports on the WLR of normal intracranial artery are limited. It might be possible to calculate the WLR using the indocyanine green (ICG) angiography, which is used to observe intracranial vessels during microsurgery. Purpose: To evaluate the WLR of normal intracranial arteries using ICG angiography. Materials and Methods: From the three cases in which ICG angiography was recorded with a ruler during microsurgery, 20 measurement points were chosen for the analysis. The ICG was injected intravenously with a dose of 0.2 mg/kg, and the vessels were inspected at high magnification using an operating microscope equipped with near-infrared illumination system. The vessel outer diameter and the luminal diameter were measured using the images before and after the ICG arrival based on the pixel ratio method using a ruler as reference, respectively. The WLR was calculated as 0.5 × (vessel outer diameter − vessel luminal diameter). Results: The WLR (mean ± standard deviation) of normal intracranial arteries was 0.086 ± 0.022. The WLR tended to be high in small arteries. Conclusion: The WLR of normal intracranial arteries calculated using ICG angiography was consistent with the WLR reported in the previous reports based on human autopsy.

  17. 3D-shaded surface rendering of gadolinium-enhanced MR angiography in congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Okuda, S.; Kikinis, R.; Dumanli, H. [Surgical Planning Laboratory, Department of Radiology, Brigham and Women' s Hospital, Boston, MA (United States); Department of Radiology, Harvard Medical School, Boston, MA (United States); Geva, T.; Powell, A.J. [Department of Cardiology, Children' s Hospital, Boston, MA (United States); Department of Pediatrics, Harvard Medical School, Boston, MA (United States); Chung, T. [Department of Radiology, Children' s Hospital, Boston, MA (United States)

    2000-08-01

    Background. Gadolinium-enhanced three-dimensional (3D) MR angiography is a useful imaging technique for patients with congenital heart disease. Objective. This study sought to determine the added value of creating 3D shaded surface displays compared to standard maximal intensity projection (MIP) and multiplanar reformatting (MPR) techniques when analyzing 3D MR angiography data. Materials and methods. Seventeen patients (range, 3 months to 51 years old) with a variety of congenital cardiovascular defects underwent gadolinium-enhanced 3D MR angiography of the thorax. Color-coded 3D shaded surface models were rendered from the image data using manual segmentation and computer-based algorithms. Models could be rotated, translocated, or zoomed interactively by the viewer. Information available from the 3D models was compared to analysis based on viewing standard MIP/MPR displays. Results. Median postprocessing time for the 3D models was 6 h (range, 3-25 h) compared to approximately 20 min for MIP/MPR viewing. No additional diagnostic information was gained from 3D model analysis. All major findings with MIP/MPR postprocessing were also apparent on the 3D models. Qualitatively, the 3D models were more easily interpreted and enabled adjacent vessels to be distinguished more readily. Conclusion. Routine use of 3D shaded surface reconstructions for visualization of contrast enhanced MR angiography in congenital heart disease cannot be recommended. 3D surface rendering may be more useful for presenting complex anatomy to an audience unfamiliar with congenital heart disease and as an educational tool. (orig.)

  18. Use of coronary CT angiography in the diagnosis of patients with suspected coronary artery disease: findings and clinical indications

    Institute of Scientific and Technical Information of China (English)

    Zhong-Hua Sun; Yu-Pin Liu; Dong-Jin Zhou; Yan Qi

    2012-01-01

    Objective To investigate the clinical applications of coronary CT angiography in patients with suspected coronary artery disease and identify factors that affect CT findings. Methods Medical records of patients suspected of coronary artery disease over a period of 12 months from a tertiary teaching hospital were retrospectively reviewed. Patient age, sex (male/female), duration of symptoms and abnormal rates of coronary CT angiography scans were analysed to investigate the relationship among these parameters. The patients by age were duration of symptoms was also classified into five groups: less than one week, one week to one month, one to three months, three to six months and more than six months. Results Of the 880 patient records reviewed, 800 met the above study criteria. Five hundred and forty nine patients demonstrated abnormal CT findings (68.6%). There was no significant difference in the percentage of abnormal CT findings based on patient sex and the duration of symptoms (P = 0.14). The abnormal rates of coronary CT angiography, however, increased significantly with increasing age (P < 0.001); with patients over 65 years of age 2.5 times more likely to have an abnormal CT scan relative to a patient under 45 years. A significant difference was found between abnormal coronary CT angiography and the duration of symptoms (P = 0.012). Conclusions Our results indicate coronary CT angiography findings are significantly related to the patient age group and duration of symptoms. Clinical referral for coronary CT angiography of patients with suspected coronary artery disease needs to be justified with regard to the judicious use of this imaging modality.

  19. Posterior Chamber Hemorrhage during Fluorescein Angiography

    Directory of Open Access Journals (Sweden)

    Manuel A. P. Vilela

    2015-01-01

    Full Text Available This paper provides the first reported case of acute posterior chamber hemorrhage during fluorescein angiography (FA. This is a case review with serial color photographs of the anterior segment. A 76-year-old male was referred for angiographic control of age-related macular degeneration. He was pseudophakic OU, BCVA 20/40 OU. He had mild hypertension, but not diabetes. He had had two previous angiograms without adverse effects. Difficulty was experienced in obtaining the images owing to a progressive reduction in the transparency of the media. A dense hemorrhage in the posterior chamber of the right eye was found, involving the visual axis. Thorough biomicroscopy, gonioscopy, and ultrasonic biomicroscopy showed that part of one of the haptics of the right intraocular lens (IOL was touching and tearing the posterior face of the iris, without any visible synechiae, iris, or angle neovascularization. Anterior segment FA and posterior ultrasonography were normal. No similar case has been described in the literature involving dense progressive bleeding located in the capsular bag and posterior chamber, without any detectable triggering ocular event other than mydriasis and fluorescein injection. Contact of the iris or sulcus with part of the intraocular lens, aggravated by the intense use of mydriatics during the FA procedure, probably caused bleeding to happen.

  20. MR imaging and angiography in tuberculous meningitis

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, R.K. [Sanjay Gandhi Postgraduate Inst. of Medical Sciences, Lucknow (India). MR Section; Gupta, S. [Sanjay Gandhi Postgraduate Inst. of Medical Sciences, Lucknow (India). MR Section; Singh, D. [Sanjay Gandhi Postgraduate Inst. of Medical Sciences, Lucknow (India). Dept. of Neurology; Sharma, B. [Sanjay Gandhi Postgraduate Inst. of Medical Sciences, Lucknow (India). Dept. of Neurology; Kohli, A. [King George Medical Coll., Lucknow (India). Dept. of Paediatrics; Gujral, R.B. [Sanjay Gandhi Postgraduate Inst. of Medical Sciences, Lucknow (India). MR Section

    1994-02-01

    MRI was performed on 26 patients with tuberculous meningitis, with particular reference to document the cranial nerve abnormalities. MR angiography (MRA) was performed in 20 of the patients. Meningeal enhancement in the basal cisterns or over the convexity of brain was seen in all patients; two show ependymal enhancement. Tuberculomas, single (3), multiple (12) or military (2) were detected in 17 patients. Of the 9 patients with cranial nerve palsies, 7 showed contrast enhancement with or without thickening of the involved nerve. Abnormality signal intensity of the involved nerve was seen on proton density and T{sub 2}-weighted images in one of these patients. MRA revealed focal arterial narrowing in 10 patients, the vessels commonly affected being the terminal segment of the internal carotid artery and the proximal segments of the middle and anterior cerebral arteries. One patient also had a small aneurysm of the proximal middle cerebral artery. Infarcts, haemorrhagic (8) or bland (6), were detected in 14 patients; most were the basal ganglia and internal capsules, large middle or anterior cerebral arterial territory infarcts being seen in only two cases. (orig.)

  1. Posterior encephalopathy with vasospasm: MRI and angiography

    Energy Technology Data Exchange (ETDEWEB)

    Weidauer, S.; Gaa, J.; Lanfermann, H.; Zanella, F.E. [Institute of Neuroradiology, University of Frankfurt, Schleusenweg 2-16, 60528, Frankfurt (Germany); Sitzer, M.; Hefner, R. [Department of Neurology, University of Frankfurt, Schleusenweg 2-16, 60528, Frankfurt (Germany)

    2003-12-01

    Posterior encephalopathy is characterised by headache, impairment of consciousness, seizures and progressive visual loss. MRI shows bilateral, predominantly posterior, cortical and subcortical lesions with a distribution. Our aim was to analyse the MRI lesion pattern and angiographic findings because the pathophysiology of posterior encephalopathy is incompletely understood. We report three patients with clinical and imaging findings consistent with posterior encephalopathy who underwent serial MRI including diffusion-weighted imaging (DWI) and construction of apparent diffusion coefficient (ADC) maps, and four-vessel digital subtraction angiography (DSA). DWI revealed symmetrical subcortical and cortical parieto-occipital high signal. High and also low ADCs indicated probable vasogenic and cytotoxic oedema. On follow-up there was focal cortical laminar necrosis, while the white-matter lesions resolved almost completely, except in the arterial border zones. DSA revealed diffuse arterial narrowing, slightly more marked in the posterior circulation. These findings suggest that posterior encephalopathy may in some cases be due to diffuse, severe vasospasm affecting especially in the parieto-occipital grey matter, with its higher vulnerability to ischemia. Cerebral vasospasm due to digitoxin intoxication, resulting in posterior encephalopathy, has not yet been described previously. (orig.)

  2. Ellipse Fitting Based Approach for Extended Object Tracking

    Directory of Open Access Journals (Sweden)

    Borui Li

    2014-01-01

    Full Text Available With the increase of sensors’ resolution, traditional object tracking technology, which ignores object’s physical extension, gradually becomes inappropriate. Extended object tracking (EOT technology is able to obtain more information about the object through jointly estimating both centroid’s dynamic state and physical extension of the object. Random matrix based approach is a promising method for EOT. It uses ellipse/ellipsoid to describe the physical extension of the object. In order to reduce the physical extension estimation error when object maneuvers, the relationship between ellipse/ellipsoid and symmetrical positive definite matrix is analyzed at first. On this basis, ellipse/ellipsoid fitting based approach (EFA for EOT is proposed based on the measurement model and centroid’s dynamic model of random matrix based EOT approach. Simulation results show that EFA is effective. The physical extension estimation error of EFA is lower than those of random matrix based approaches when object maneuvers. Besides, the estimation error of centroid’s dynamic state of EFA is also lower.

  3. The Process - based Approach in English Writing Class%The Process-based Approach in English Writing Class

    Institute of Scientific and Technical Information of China (English)

    秦梅

    2007-01-01

    English writing is gaining high attention and emphasis in our college syllabus. It is a complicated process of written communication. In the process, the four basic skills-speaking, reading, listening and writing are organically integrated together. This paper is about the processbased approach in English writing class and its aim to emphasize the importance of process -based approach to writing. There are four parts in this paper. I start with a brief introduction to the importance of writing. Next, I will introduce my practice in English writing class. Then I will comment on the process approach and then make a little revision.

  4. A multiparameter chaos control method based on OGY approach

    Energy Technology Data Exchange (ETDEWEB)

    Souza de Paula, Aline [Universidade Federal do Rio de Janeiro, COPPE - Department of Mechanical Engineering, 21.941.972 - Rio de Janeiro - RJ, P.O. Box 68.503 (Brazil)], E-mail: alinesp@ufrj.br; Amorim Savi, Marcelo [Universidade Federal do Rio de Janeiro, COPPE - Department of Mechanical Engineering, 21.941.972 - Rio de Janeiro - RJ, P.O. Box 68.503 (Brazil)], E-mail: savi@mecanica.ufrj.br

    2009-05-15

    Chaos control is based on the richness of responses of chaotic behavior and may be understood as the use of tiny perturbations for the stabilization of a UPO embedded in a chaotic attractor. Since one of these UPO can provide better performance than others in a particular situation the use of chaos control can make this kind of behavior to be desirable in a variety of applications. The OGY method is a discrete technique that considers small perturbations promoted in the neighborhood of the desired orbit when the trajectory crosses a specific surface, such as a Poincare section. This contribution proposes a multiparameter semi-continuous method based on OGY approach in order to control chaotic behavior. Two different approaches are possible with this method: coupled approach, where all control parameters influences system dynamics although they are not active; and uncoupled approach that is a particular case where control parameters return to the reference value when they become passive parameters. As an application of the general formulation, it is investigated a two-parameter actuation of a nonlinear pendulum control employing coupled and uncoupled approaches. Analyses are carried out considering signals that are generated by numerical integration of the mathematical model using experimentally identified parameters. Results show that the procedure can be a good alternative for chaos control since it provides a more effective UPO stabilization than the classical single-parameter approach.

  5. Intelligent Transportation and Evacuation Planning A Modeling-Based Approach

    CERN Document Server

    Naser, Arab

    2012-01-01

    Intelligent Transportation and Evacuation Planning: A Modeling-Based Approach provides a new paradigm for evacuation planning strategies and techniques. Recently, evacuation planning and modeling have increasingly attracted interest among researchers as well as government officials. This interest stems from the recent catastrophic hurricanes and weather-related events that occurred in the southeastern United States (Hurricane Katrina and Rita). The evacuation methods that were in place before and during the hurricanes did not work well and resulted in thousands of deaths. This book offers insights into the methods and techniques that allow for implementing mathematical-based, simulation-based, and integrated optimization and simulation-based engineering approaches for evacuation planning. This book also: Comprehensively discusses the application of mathematical models for evacuation and intelligent transportation modeling Covers advanced methodologies in evacuation modeling and planning Discusses principles a...

  6. [Internet-based approaches in the therapy of eating disorders].

    Science.gov (United States)

    Fichter, M M; Quadflieg, N; Nisslmüller, K; Lindner, S; Voderholzer, U; Wünsch-Leiteritz, W; Osen, B; Huber, T; Zahn, S; Meermann, R; Irrgang, V; Bleichner, F

    2011-09-01

    Recent technological developments of communication media offer new approaches to diagnostic and therapeutic interactions with patients. One major development is Internet-based primary prevention in vulnerable individuals not yet suffering as well as the development of new therapeutic approaches for affected individuals based on the experiences of guided self-help through CD, DVD or bibliotherapy. The eating disorder literature shows several interesting, partly controlled and randomized, studies on bulimia nervosa, a few studies on binge eating disorder and no studies on anorexia nervosa. As part of the German Eating Disorder Network on Psychotherapy (EDNET) a 9-month Internet-based relapse prevention program for patients with anorexia nervosa after inpatient treatment was evaluated. Conception, first experiences and first results of the Internet-based relapse prevention program for anorexia nervosa are reported.

  7. User-based and Cognitive Approaches to Knowledge Organization

    DEFF Research Database (Denmark)

    Hjørland, Birger

    2013-01-01

    In the 1970s and 1980s, forms of user-based and cognitive approaches to knowledge organization came to the forefront as part of the overall development in library and information science and in the broader society. The specific nature of userbased approaches is their basis in the empirical studies...... of users or the principle that users need to be involved in the construction of knowledge organization systems. It might seem obvious that user-friendly systems should be designed on user studies or user involvement, but extremely successful systems such as Apple’s iPhone, Dialog’s search system and Google......’s PageRank are not based on the empirical studies of users. In knowledge organization, the Book House System is one example of a system based on user studies. In cognitive science the important WordNet database is claimed to be based on psychological research. This article considers such examples...

  8. Preoperative evaluation of neurovascular relationship by using contrast-enhanced and unenhanced 3D time-of-flight MR angiography in patients with trigeminal neuralgia

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Zhou; Zhiling, Liu; Chuanfu, Li; Qingshi Zeng (Dept. of Radiology, Qilu Hospital of Shandong Univ., Jinan (China)), email: zengqingshi@yahoo.cn; Chuncheng, Qu (Dept. of Neurosurgery, the Second Hospital of Shandong Univ., Jinan (China)); Shilei, Ni (Dept. of Neurosurgery, Qilu Hospital of Shandong Univ., Jinan (China))

    2011-10-15

    Background Microvascular decompression is an etiological strategy for the therapy of trigeminal neuralgia (TN). Preoperative identification of neurovascular compression, therefore, could have an impact on the determination of appropriate treatment for TN. Purpose To evaluate the value of contrast-enhanced and unenhanced three-dimensional (3D) time-of-flight (TOF) MR angiography in the visualization of neurovascular relationship in patients with TN. Material and Methods Thirty-seven patients with unilateral TN underwent unenhanced and contrast-enhanced 3D TOF MR angiography with a 3.0-T MR system. Images were reviewed by a radiologist blinded to clinical details. Vascular contact with the trigeminal nerve was identified, and the nature of the involved vessels (artery or vein) was determined. All patients underwent microvascular decompression. Results In 37 patients with TN, contrast-enhanced 3D TOF MR angiography identified surgically verified neurovascular contact in 35 of 36 symptomatic nerves, and there was no false-positive. Based on surgical findings, the sensitivity of MR imaging was 97.2% and specificity 100%. The nature of the offending vessel was correctly identified in 94.4% of the patients by using the combination of contrast-enhanced and unenhanced MR angiography. Conclusion Contrast-enhanced 3D TOF MR angiography is useful in the detection of vascular contact with the trigeminal nerve in patients with TN, and this MR imaging in combination with unenhanced MR angiography could help in the identification of the nature of the responsible vessels

  9. Low-dose prospective ECG-triggering dual-source CT angiography in infants and children with complex congenital heart disease: first experience

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Zhaoping; Wang, Ximing; Duan, Yanhua; Wu, Lebin; Wu, Dawei; Chao, Baoting; Liu, Cheng; Xu, Zhuodong [Shandong University, Shandong Medical Imaging Research Institute, Jinan, Shandong (China); Li, Hongxin; Liang, Fei [Shandong Provincial Hospital, Department of Cardiovascular Surgery, Jinan, Shandong (China); Xu, Jian; Chen, Jiuhong [Siemens. Ltd. China, CT Research Collaboration, Beijing (China)

    2010-10-15

    To explore the clinical value of low-dose prospective ECG-triggering dual-source CT (DSCT) angiography in infants and children with complex congenital heart disease (CHD) compared with transthoracic echocardiography (TTE). Thirty-five patients (mean age: 16 months, range: 2 months to 6 years; male 15; mean weight: 12 kg) underwent low-dose prospective ECG-triggering DSCT angiography and TTE. Surgeries were performed in 29 patients, and conventional cardiac angiography (CCA) was performed in 8 patients. The accuracy was calculated based on the surgical and/or CCA findings. The overall imaging quality was evaluated on a five-point scale. A total of 146 separate cardiovascular deformities were confirmed. DSCT missed three atrial septal defects and a patent ductus arteriosus. The accuracy of DSCT angiography and TTE was 97.3% (142/146) and 92.5% (135/146), respectively. Overall test parameters for DSCT angiography and TTE were similar (sensitivity, 97.3% vs 92.5%; specificity, 99.8% vs 99.8%). The average subjective image quality score was 4.3 {+-} 0.7. The mean effective dose was 0.38 {+-} 0.09 mSv. Prospective ECG-triggering DSCT angiography with a very low effective radiation dose allows the accurate diagnosis of anomalies in infants and children with complex CHD compared with TTE. It has great promise to become a commonly used second-line technique for complex CHD. (orig.)

  10. A New ETL Approach Based on Data Virtualization

    Institute of Scientific and Technical Information of China (English)

    郭树盛; 袁子牧; 孙傲冰; 岳强

    2015-01-01

    ETL (Extract-Transform-Load) usually includes three phases: extraction, transformation, and loading. In building data warehouse, it plays the role of data injection and is the most time-consuming activity. Thus it is necessary to improve the performance of ETL. In this paper, a new ETL approach, TEL (Transform-Extract-Load) is proposed. The TEL approach applies virtual tables to realize the transformation stage before extraction stage and loading stage, without data staging area or staging database which stores raw data extracted from each of the disparate source data systems. The TEL approach reduces the data transmission load, and improves the performance of query from access layers. Experimental results based on our proposed benchmarks show that the TEL approach is feasible and practical.

  11. Diabetic Macular Ischemia Diagnosis: Comparison between Optical Coherence Tomography Angiography and Fluorescein Angiography

    Science.gov (United States)

    Lima, Talita Toledo; Louzada, Ricardo Noguera; Rassi, Alessandra Thome; Isaac, David Leonardo Cruvinel; Avila, Marcos

    2016-01-01

    Purpose. To compare fluorescein angiography (FA) and optical coherence tomography angiography (OCTA) images of foveal avascular zone (FAZ) in patients with diabetic retinopathy (DR) with and without diabetic macular ischemia (DMI). Methods. The Wilcoxon signed-rank test was used to compare area measurements and p values of <0.05 were considered statistically significant. FA and OCTA images were independently graded by 2 observers that reached agreement regarding quantitative DMI according established protocols. The ischemic area was divided into “large” macular ischemia (superior to 0.32 mm2) and “small” (inferior to 0.32 mm2) groups. Quantitative analyses of the FAZ were performed using custom software. Results. Thirty-four eyes from 34 diabetic patients were enrolled. Subjects with DMI presented a mean area on FA and OCTA of 0.68 ± 0.53 mm2 and 0.58 ± 0.35 mm2, respectively (p = 0.1374). Patients without DMI presented a mean area on FA and OCTA of 0.19 ± 0.67 mm2 and 0.20 ± 0.79 mm2, respectively (p = 0.9594). The ICC for the FAZ measurements between the 2 observers on FA and OCTA was 0.96 and 0.92, respectively. Conclusion. OCTA represents a novel technique for the diagnosis of DMI and it may become an alternative to FA for this purpose. PMID:27891250

  12. A Mindfulness-Based Approach to the Treatment of Insomnia

    OpenAIRE

    Ong, Jason; Sholtes, David

    2010-01-01

    Mindfulness meditation has emerged as a novel approach to emotion regulation and stress reduction that has several health benefits. Preliminary work has been conducted on mindfulness-based therapy for insomnia (MBT-I), a meditation-based program for individuals suffering from chronic sleep disturbance. This treatment integrates behavioral treatments for insomnia with the principles and practices of mindfulness meditation. A case illustration of a chronic insomnia sufferer demonstrates the app...

  13. Complexity, Networking, & Effects-Based Approaches to Operations

    Science.gov (United States)

    2006-06-01

    40 Figure 10. Miller’s Living Systems Model ....................................47 Figure 11. State versus Non- State Living Systems...human organizations and to apply it in an effects-based context. State and non- state living systems The model described above extrapolates quite... STATE LIVING SYSTEMS MODEL 52 Complexity, Networking, and Effects-Based Approaches to Operations The living systems model organizations such as the

  14. A chaos-based approach for information hiding security

    OpenAIRE

    Bahi, Jacques M.; Guyeux, Christophe

    2010-01-01

    This paper introduces a new framework for data hiding security. Contrary to the existing ones, the approach introduced here is not based on probability theory. In this paper, a scheme is considered as secure if its behavior is proven unpredictable. The objective of this study is to enrich the existing notions of data hiding security with a new rigorous and practicable one. This new definition of security is based on the notion of topological chaos. It could be used to reinforce the confidence...

  15. An Efficient Audio Classification Approach Based on Support Vector Machines

    Directory of Open Access Journals (Sweden)

    Lhoucine Bahatti

    2016-05-01

    Full Text Available In order to achieve an audio classification aimed to identify the composer, the use of adequate and relevant features is important to improve performance especially when the classification algorithm is based on support vector machines. As opposed to conventional approaches that often use timbral features based on a time-frequency representation of the musical signal using constant window, this paper deals with a new audio classification method which improves the features extraction according the Constant Q Transform (CQT approach and includes original audio features related to the musical context in which the notes appear. The enhancement done by this work is also lay on the proposal of an optimal features selection procedure which combines filter and wrapper strategies. Experimental results show the accuracy and efficiency of the adopted approach in the binary classification as well as in the multi-class classification.

  16. From equation to inequality using a function-based approach

    Science.gov (United States)

    Verikios, Petros; Farmaki, Vassiliki

    2010-06-01

    This article presents features of a qualitative research study concerning the teaching and learning of school algebra using a function-based approach in a grade 8 class, of 23 students, in 26 lessons, in a state school of Athens, in the school year 2003-2004. In this article, we are interested in the inequality concept and our aim is to investigate if and how our approach could facilitate students to comprehend inequality and to solve problems related to this concept. Data analysis showed that, in order to comprehend the new concept, the students should make a transition from equation to inequality. The role of the situation context proved decisive in this transition and in making sense of involved symbols. Also, students used function representations as problem-solving strategies in problems that included inequalities. However, the extension of the function-based approach in solving an abstract equation or inequality proved problematic for the students.

  17. A concept-based approach to text categorization

    NARCIS (Netherlands)

    Schijvenaars, B.J.A.; Schuemie, M.J.; Mulligen, E.M. van; Weeber, M.; Jelier, R.; Mons, B.; Kors, J.A.; Kraaij, W.

    2005-01-01

    The Biosemantics group (Erasmus University Medical Center, Rotterdam) participated in the text categorization task of the Genomics Track. We followed a thesaurus-based approach, using the Collexis indexing system, in combination with a simple classification algorithm to assign a document to one of t

  18. An Evidence-Based Approach to Introductory Chemistry

    Science.gov (United States)

    Johnson, Philip

    2014-01-01

    Drawing on research into students' understanding, this article argues that the customary approach to introductory chemistry has created difficulties for students. Instead of being based on the notion of "solids, liquids and gases", introductory chemistry should be structured to develop the concept of a substance. The concept of a…

  19. Non-frontal model based approach to forensic face recognition

    NARCIS (Netherlands)

    Dutta, Abhishek; Veldhuis, Raymond; Spreeuwers, Luuk

    2012-01-01

    In this paper, we propose a non-frontal model based approach which ensures that a face recognition system always gets to compare images having similar view (or pose). This requires a virtual suspect reference set that consists of non-frontal suspect images having pose similar to the surveillance vie

  20. From Equation to Inequality Using a Function-Based Approach

    Science.gov (United States)

    Verikios, Petros; Farmaki, Vassiliki

    2010-01-01

    This article presents features of a qualitative research study concerning the teaching and learning of school algebra using a function-based approach in a grade 8 class, of 23 students, in 26 lessons, in a state school of Athens, in the school year 2003-2004. In this article, we are interested in the inequality concept and our aim is to…

  1. Saccharide-based Approach to Green Metallic Nanostructure Synthesis

    DEFF Research Database (Denmark)

    Engelbrekt, Christian; Sørensen, Karsten Holm; Jensen, Palle Skovhus

    A green approach to solution synthesis of metallic nanoparticles has been developed using harmless and bioapplicable chemicals as well as moderate temperatures. Metal precursors are reduced by glucose/buffers and sterically stabilized by starch. The saccharide based procedure is highly diverse...

  2. Knowledge-based Approach for Event Extraction from Arabic Tweets

    Directory of Open Access Journals (Sweden)

    Mohammad AL-Smadi

    2016-06-01

    Full Text Available Tweets provide a continuous update on current events. However, Tweets are short, personalized and noisy, thus raises more challenges for event extraction and representation. Extracting events out of Arabic tweets is a new research domain where few examples – if any – of previous work can be found. This paper describes a knowledge-based approach for fostering event extraction out of Arabic tweets. The approach uses an unsupervised rule-based technique for event extraction and provides a named entity disambiguation of event related entities (i.e. person, organization, and location. Extracted events and their related entities are populated to the event knowledge base where tagged tweets’ entities are linked to their corresponding entities represented in the knowledge base. Proposed approach was evaluated on a dataset of 1K Arabic tweets covering different types of events (i.e. instant events and interval events. Results show that the approach has an accuracy of, 75.9% for event trigger extraction, 87.5% for event time extraction, and 97.7% for event type identification.

  3. Employers' Approaches to Work-Based Training in Britain.

    Science.gov (United States)

    Hillage, Jim

    1996-01-01

    The British Labour Force Survey indicates that work-based training is skewed toward service sector occupations and high-level workers. Few employers have a formal or systematic training approach. Lower-skilled, more disadvantaged workers have the least access to education and training. (SK)

  4. Agile Service Development: A Rule-Based Method Engineering Approach

    NARCIS (Netherlands)

    Hoppenbrouwers, Stijn; Zoet, Martijn; Versendaal, Johan; Weerd, Inge van de

    2011-01-01

    Agile software development has evolved into an increasingly mature software development approach and has been applied successfully in many software vendors’ development departments. In this position paper, we address the broader agile service development. Based on method engineering principles we de

  5. Training Team Problem Solving Skills: An Event-Based Approach.

    Science.gov (United States)

    Oser, R. L.; Gualtieri, J. W.; Cannon-Bowers, J. A.; Salas, E.

    1999-01-01

    Discusses how to train teams in problem-solving skills. Topics include team training, the use of technology, instructional strategies, simulations and training, theoretical framework, and an event-based approach for training teams to perform in naturalistic environments. Contains 68 references. (Author/LRW)

  6. An Approach to Quality Estimation in Model-Based Development

    DEFF Research Database (Denmark)

    Holmegaard, Jens Peter; Koch, Peter; Ravn, Anders Peter

    2004-01-01

    We present an approach to estimation of parameters for design space exploration in Model-Based Development, where synthesis of a system is done in two stages. Component qualities like space, execution time or power consumption are defined in a repository by platform dependent values. Connectors...

  7. An approach for activity-based DEVS model specification

    DEFF Research Database (Denmark)

    Alshareef, Abdurrahman; Sarjoughian, Hessam S.; Zarrin, Bahram

    2016-01-01

    activity-based behavior modeling of parallel DEVS atomic models. We consider UML activities and actions as fundamental units of behavior modeling, especially in the presence of recent advances in the UML 2.5 specifications. We describe in detail how to approach activity modeling with a set of elemental...

  8. Graphene metamaterials based tunable terahertz absorber: effective surface conductivity approach.

    Science.gov (United States)

    Andryieuski, Andrei; Lavrinenko, Andrei V

    2013-04-08

    In this paper we present the efficient design of functional thin-film metamaterial devices with the effective surface conductivity approach. As an example, we demonstrate a graphene based perfect absorber. After formulating the requirements to the perfect absorber in terms of surface conductivity we investigate the properties of graphene wire medium and graphene fishnet metamaterials and demonstrate both narrowband and broadband tunable absorbers.

  9. Graphene metamaterials based tunable terahertz absorber: effective surface conductivity approach

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Lavrinenko, Andrei

    2013-01-01

    In this paper we present the efficient design of functional thin-film metamaterial devices with the effective surface conductivity approach. As an example, we demonstrate a graphene based perfect absorber. After formulating the requirements to the perfect absorber in terms of surface conductivity...... we investigate the properties of graphene wire medium and graphene fishnet metamaterials and demonstrate both narrowband and broadband tunable absorbers....

  10. A sampling-based approach to probabilistic pursuit evasion

    KAUST Repository

    Mahadevan, Aditya

    2012-05-01

    Probabilistic roadmaps (PRMs) are a sampling-based approach to motion-planning that encodes feasible paths through the environment using a graph created from a subset of valid positions. Prior research has shown that PRMs can be augmented with useful information to model interesting scenarios related to multi-agent interaction and coordination. © 2012 IEEE.

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

    Institute of Scientific and Technical Information of China (English)

    Zhonghua Sun

    2011-01-01

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

  12. Clinical applications of MR digital subtraction angiography for the evaluation of intracranial vascular and tumorous lesions

    Energy Technology Data Exchange (ETDEWEB)

    Katase, Shichiro; Tsuchiya, Kazuhiro; Hachiya, Junichi [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine

    2001-07-01

    MR digital subtraction angiography (MR DSA), which is performed by a rapid two-dimensional T1-weighted sequence in combination with bolus injection of gadolinium-based contrast agent was applied to the evaluation of cerebral arteriovenous malformations (AVMs), brain tumors (intraaxial and extraaxial tumors), and other vascular lesions. This study was performed to evaluate the clinical usefulness of the method in the diagnosis of these lesions. We studied 19 cases of cerebral AVM, 36 cases of intraaxial tumor (metastatic brain tumors in 14, glioblastomas in five, astrocytomas in eight, malignant lymphomas in four, pineal tumors in two, and other tumors, in three), 34 cases of extraaxial tumor (meningiomas in 29, and pituitary adenomas in five), and 10 cases of other vascular lesions (cerebral aneurysms in five, venous thrombosis in two, and other lesion in three). For cerebral AVMs, the feeder, nidus, and drainer were evaluated on a 4 - point grading scale (0=poor, 1=fair, 2=good, 3=excellent), and the results obtained were compared with those of conventional cerebral angiography or MR angiography using the postcontrast three-dimensional time-of-flight method. Brain tumors were classified into six enhancement patterns, and were compared with the findings of conventional cerebral angiography. Other vascular lesions were assessed visually. All cases were evaluated independently by two radiologists, and inter-observer agreement was assessed using the {kappa}-test. In all cerebral AVM cases, the hemodynamics of the feeder, nidus, and drainer could be observed. In all but five brain tumor cases, tumor stain could be confirmed in MR DSA images. The findings of tumor stain corresponded to those of cerebral angiographic images. For other vascular lesions, results of lesion detection and lesion morphology were almost in congruence with other methods. MR DSA provides information on the hemodynamics of vascular and tumorous lesions. When used in conjunction with routine MR

  13. The diagnostic accuracy of time-of-flight MR angiography in diagnosing Moyamoya disease

    Energy Technology Data Exchange (ETDEWEB)

    Shono, Tadahisa; Ikezaki, Kiyonobu; Matsushima, Toshio; Inoue, Tooru; Fujii, Kiyotaka; Fukui, Masashi [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

    1995-09-01

    Conventional cerebral angiography is essential for achieving the diagnosis of Moyamoya disease. It is, however, an invasive examination, especially for the pediatric patients. In this paper, we report on the results of an investigation as to whether MRA is able to accurately visualize the steno-occlusive changes in the carotid fork and the basal moyamoya vessels less invasively. Twenty patients among them, 16 children who were diagnosed as having Moyamoya disease with conventional angiography underwent MRI and MRA using a 1.5T MR unit (Signa, G.E.). Angiographically, 37 sides were determined to be in stage 3. MRA was performed using two-dimensional time-of-flight (2D-TOF), 3D-TOF, and gadolinium (Gd)-enhanced 3D-TOF methods. The 3D-TOF MRAs showed almost equal sensitivity to that of conventional angiography for the detection of steno-occlusive changes in the carotid fork. However, it was difficult to visualize the moyamoya vessels clearly. Further, 3D-TOF, 2D-TOF, and Gd-enhanced 3D-TOF methods depicted the moyamoya vessels in 65%, 79%, and 80% of the examined sides, respectively. In contrast, MRI visualized the moyamoya vessels as multiple flow voids in the basal ganglia in 38 of 40 sides (95%). Based on the above findings, it was thus concluded that approximately 90% of the stage 3 Moyamoya disease cases could be diagnosed by a combination of 3D-TOF MRA and MRI without the use of conventional angiography. (author).

  14. Cerebral angiography in patients with complicated migraine

    Energy Technology Data Exchange (ETDEWEB)

    Zeiler, K.; Wessely, P.; Holzner, F.

    1985-08-01

    38 patients (mean age: 29 years) were investigated by means of complete 4-vessel angiography: all of them were suffering from complicated migraine without detectable vascular malformation. Stenoses of the great craniocervical vessels were found in 11 patients (28.9%), but there was not a single case of vascular occlusion. A correlation between the localization of the stenosis, the localization of the headache and the presumed region of the transient cerebral function disturbance was found only in a few patients. Concerning the morphological changes of the small intracranial arterial branches, there was hardly an difference between clinically affected and non-affected territories of the middle cerebral artery. The angiograms of the 38 cases of complicated migraine were compared with the angiograms of 40 patients suffering from strokes in the young and those of 49 patients with transient ischaemic attacks. There were remarkably fewer stenoses or occlusions in the great craniocervical arteries of patients suffering from complicated migraine (28.9%) than in the vessels of cases of stroke in the young (52.5%). However, the incidence was comparable with the results in patients with transient ischaemic attacks (34.7%). The degree of morphological changes in the small intracranial arterial branches is likely to depend primarily on the patient's age and less on the diagnosis. The results suggest that in almost 30% of patients with complicated migraine - even at juvenile age-stenoses of the great craniocervical vessels might be found. However, considering the fact that most of the stenoses are without haemodynamic significance and their localization is not in agreement with the clinical data, the pathogenetic value of these vessel wall changes is highly questionable. (Author).

  15. Digital subtraction angiography in cerebral infarction

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sin Young; Kim, Ji Hun; Suh, Hong Kil; Kim, Hyo Heon; Kwack, Eun Young; Lee, Il Seong [College of Medicine Hallym University, Seoul (Korea, Republic of)

    1995-01-15

    The usefulness and radiographic findings of the angiography in cerebral infarction are well known. We attempted to evaluate the angiographic causes, findings, and the usefulness of DSA in cerebral infarction. The authors reviewed retrospectively DSA images of 51 patients who were diagnosed as having cerebral infarction by brain CT and/or MRI and clinical settings. DSA was performed in all 51 patients, and in 3 patients, conventional angiogram was also done. Both carotid DSA images were obtained in AP, lateral, oblique projections, and one or both vertebral DSA images in AP and lateral. The authors reviewed the patient's charts for symptoms, operative findings and final diagnosis, and analysed DSA findings of cerebral atherosclerosis with focus on 6 major cerebral arteries. Among the 51 patients of cerebral infarction 43 patients (84.3%) had cerebral atherosclerosis, 1 dissecting aneurysm, 1 moyamoya disease and 6 negative in angiogram. DSA findings of cerebral atherosclerosis were multiple narrowing in 42 patients (97.7%), tortuosity in 22 (51.2%), dilatation in 14, occlusion in 12, avascular region in 8, collaterals in 7, ulcer in 6, and delayed washout of contrast media in 3. In cerebral atherosclerosis, internal carotid artery was involved in 37 patients (86.0%), middle cerebral artery in 29 (67.4%) posterior cerebral artery in 28, anterior cerebral artery in 26, vertebral artery in 22, and basilar artery in 15. Intracranial involvement of cerebral atherosclerosis (64.9%) was more common than extracranial involvement (16.2%). In cerebral infarction MRA may be the screening test, but for more precise evaluation of vascular abnormality and its extent, DSA should be considered.

  16. Variation-based approach to image segmentation Variation-based approach to image segmentation

    Institute of Scientific and Technical Information of China (English)

    张永平; 郑南宁; 赵荣椿

    2001-01-01

    A new approach to image segmentation is presented using a variation framework. Regarding the edge points as interpolating points and minimizing an energy functional to interpolate a smooth threshold surface it carries out the image segmentation. In order to preserve the edge information of the original image in the threshold surface, without unduly sharping the edge of the image, a non-convex energy functional is adopted. A relaxation algorithm with the property of global convergence, for solving the optimization problem, is proposed by introducing a binary energy. As a result the non-convex optimization problem is transformed into a series of convex optimization problems, and the problem of slow convergence or nonconvergence is solved. The presented method is also tested experimentally. Finally the method of determining the parameters in optimizing is also explored.   

  17. 循证护理模式在全脑血管造影术患者围术期舒适管理中的应用%Application of Evidence-based Nursing to Comfort Management of the Patients with Aortocranial Angiography during Perioperative Period

    Institute of Scientific and Technical Information of China (English)

    苏舒曼

    2014-01-01

    Objective:To explore the effects of evidence-based nursing applied to comfort management of the patients with aortocranial angiography during perioperative period. Methods:Eighty patients were randomized into the control group and the observation group. The control group received routine nursing, and the observation group evidence-based nursing, comfort degree after the surgery and satisfaction degree to the care of both groups were compared. Results:The ratio and the degree of discomfort in the observation group were less, the complications of puncture places in the observation group were notable lower than these of the control group (P<0.05). Satisfaction degree of the patients to the care was improved remarkably. Conclusion:The application of evidence-based nursing to comfort management of the patients with aortocranial angiography during perioperative period could clearly re-duce the discomfort and complications after the operation, at the same time, increase satisfaction degree of the pa-tients.%目的:探讨循证护理模式在全脑血管造影术患者围术期舒适管理中的应用效果。方法:将80例患者随机分为对照组40例和观察组40例。对照组采用常规护理模式,观察组采用循证护理模式,比较2组患者术后的舒适度及对护理工作的满意度。结果:观察组发生不适的比例及程度均较轻,穿刺部位并发症明显低于对照组(P<0.05)。患者对护理工作的满意度明显提高。结论:将循证护理的理念融入全脑血管造影术围术期舒适护理管理过程中,能够明显减轻术后的不适,减少并发症发生,同时提高患者的满意度。

  18. An Efficient Soft Set-Based Approach for Conflict Analysis.

    Directory of Open Access Journals (Sweden)

    Edi Sutoyo

    Full Text Available Conflict analysis has been used as an important tool in economic, business, governmental and political dispute, games, management negotiations, military operations and etc. There are many mathematical formal models have been proposed to handle conflict situations and one of the most popular is rough set theory. With the ability to handle vagueness from the conflict data set, rough set theory has been successfully used. However, computational time is still an issue when determining the certainty, coverage, and strength of conflict situations. In this paper, we present an alternative approach to handle conflict situations, based on some ideas using soft set theory. The novelty of the proposed approach is that, unlike in rough set theory that uses decision rules, it is based on the concept of co-occurrence of parameters in soft set theory. We illustrate the proposed approach by means of a tutorial example of voting analysis in conflict situations. Furthermore, we elaborate the proposed approach on real world dataset of political conflict in Indonesian Parliament. We show that, the proposed approach achieves lower computational time as compared to rough set theory of up to 3.9%.

  19. An Efficient Soft Set-Based Approach for Conflict Analysis

    Science.gov (United States)

    Sutoyo, Edi; Mungad, Mungad; Hamid, Suraya; Herawan, Tutut

    2016-01-01

    Conflict analysis has been used as an important tool in economic, business, governmental and political dispute, games, management negotiations, military operations and etc. There are many mathematical formal models have been proposed to handle conflict situations and one of the most popular is rough set theory. With the ability to handle vagueness from the conflict data set, rough set theory has been successfully used. However, computational time is still an issue when determining the certainty, coverage, and strength of conflict situations. In this paper, we present an alternative approach to handle conflict situations, based on some ideas using soft set theory. The novelty of the proposed approach is that, unlike in rough set theory that uses decision rules, it is based on the concept of co-occurrence of parameters in soft set theory. We illustrate the proposed approach by means of a tutorial example of voting analysis in conflict situations. Furthermore, we elaborate the proposed approach on real world dataset of political conflict in Indonesian Parliament. We show that, the proposed approach achieves lower computational time as compared to rough set theory of up to 3.9%. PMID:26928627

  20. An Efficient Soft Set-Based Approach for Conflict Analysis.

    Science.gov (United States)

    Sutoyo, Edi; Mungad, Mungad; Hamid, Suraya; Herawan, Tutut

    2016-01-01

    Conflict analysis has been used as an important tool in economic, business, governmental and political dispute, games, management negotiations, military operations and etc. There are many mathematical formal models have been proposed to handle conflict situations and one of the most popular is rough set theory. With the ability to handle vagueness from the conflict data set, rough set theory has been successfully used. However, computational time is still an issue when determining the certainty, coverage, and strength of conflict situations. In this paper, we present an alternative approach to handle conflict situations, based on some ideas using soft set theory. The novelty of the proposed approach is that, unlike in rough set theory that uses decision rules, it is based on the concept of co-occurrence of parameters in soft set theory. We illustrate the proposed approach by means of a tutorial example of voting analysis in conflict situations. Furthermore, we elaborate the proposed approach on real world dataset of political conflict in Indonesian Parliament. We show that, the proposed approach achieves lower computational time as compared to rough set theory of up to 3.9%.

  1. The cortex-based alignment approach to TMS coil positioning.

    Science.gov (United States)

    Duecker, Felix; Frost, Martin A; de Graaf, Tom A; Graewe, Britta; Jacobs, Christianne; Goebel, Rainer; Sack, Alexander T

    2014-10-01

    TMS allows noninvasive manipulation of brain activity in healthy participants and patients. The effectiveness of TMS experiments critically depends on precise TMS coil positioning, which is best for most brain areas when a frameless stereotactic system is used to target activation foci based on individual fMRI data. From a purely scientific perspective, individual fMRI-guided TMS is thus the method of choice to ensure optimal TMS efficiency. Yet, from a more practical perspective, such individual functional data are not always available, and therefore alternative TMS coil positioning approaches are often applied, for example, based on functional group data reported in Talairach coordinates. We here propose a novel method for TMS coil positioning that is based on functional group data, yet only requires individual anatomical data. We used cortex-based alignment (CBA) to transform individual anatomical data to an atlas brain that includes probabilistic group maps of two functional regions (FEF and hMT+/V5). Then, these functional group maps were back-transformed to the individual brain anatomy, preserving functional-anatomical correspondence. As a proof of principle, the resulting CBA-based functional targets in individual brain space were compared with individual FEF and hMT+/V5 hotspots as conventionally localized with individual fMRI data and with targets based on Talairach coordinates as commonly done in TMS research in case only individual anatomical data are available. The CBA-based approach significantly improved localization of functional brain areas compared with traditional Talairach-based targeting. Given the widespread availability of CBA schemes and preexisting functional group data, the proposed procedure is easy to implement and at no additional measurement costs. However, the accuracy of individual fMRI-guided TMS remains unparalleled, and the CBA-based approach should only be the method of choice when individual functional data cannot be obtained or

  2. 分频幅去相干血管成像%Optical coherence tomography angiography with split-spectrum amplitude decorrelation angiography

    Institute of Scientific and Technical Information of China (English)

    王倩; 魏文斌

    2016-01-01

    Optical coherence tomography angiography (OCTA) is a new method of analysis based on high-resolution imaging techniques whereby the retinal and choroidal circulation can be visualized without the need to injecting any contrast agent.OCTA operates on the principle that,all other elements remaining the same,the only difference between sequentially obtained OCT cross-sectional scans in a particular eye is attributed to motion of erythrocytes within the retinal and choroidal vasculature.Recently,a new algorithm——split-spectrum amplitude decorrelation angiography (SSADA) has been used in OCTA.It can identify movement orthogonal or transversal to the OCT beam,quantifying flow independent of the Doppler angle.An additional advantage of the amplitude-based technology,in comparison with the phase-based,is that the latter is more significantly degraded by image noise and background tissue motion.OCTA with SSADA has been widely used in various kinds of ocular diseases,such as choroidal neovascularization,diabetic retinopathy and retinal vascular occlusions and it is very important in the diagnosis and follow up in those diseases.%相干光断层扫描血管成像(optical coherence tomography angiography,OCTA)通过比较同一位置的不同扫描,去除不变的结构,即可在不使用造影剂的情况下观察到有红细胞流动的视网膜和脉络膜血管结构.目前,一种新的运算方法——分频幅去相干血管成像(split-spectrum amplitude decorrelation angiography,SSADA)的应用,大大改善了OCTA的信噪比.与其他OCTA不同的是,SSADA OCT可获取与OCT光波平行或垂直的血流信号,不依赖多普勒角,并且图像噪音、组织运动等噪音较小.目前SSADA OCT已越来越多地应用于多种眼部疾病中,如脉络膜新生血管性疾病、糖尿病视网膜病变,视网膜血管阻塞等,在这些疾病的诊断、随访中均有重要意义.

  3. An Ontology Based Approach to Implement the Online Recommendation System

    Directory of Open Access Journals (Sweden)

    Vijayakumar Mohanraj

    2011-01-01

    Full Text Available Problem statement: Every web user has different intent when accessing the information on website. The primary goal of recommendation system is to anticipate the user intent and recommend the web pages that contain user expected information. Effective recommendation of web pages involves two important challenges: accurately identifying the user intent and predict the result show that novel web usage mining method and ontological concept scoring algorithm based on website domain ontological profile helps the recommendation system imminent navigation pattern in such a way that it provides required content while users browse the predicted navigation. Approach: We present a ontology based approach to implement recommendation system that involves applying innovative web usage mining on log system to discover all possible imminent navigation patterns of current user and resolve any uncertainties in discovering the navigation pattern by applying ontological concept based similarity comparison and scoring algorithm. Results: result show that novel web usage mining method and ontological concept scoring algorithm based on website domain ontological profile helps the recommendation system to predict and present most relevant navigation pattern to users. Conclusion: our recommendation system confirms that ontology based approach should be used to ensure excellent accuracy in predicting and capturing future navigation pattern of web user.

  4. Image-Based Learning Approach Applied to Time Series Forecasting

    Directory of Open Access Journals (Sweden)

    J. C. Chimal-Eguía

    2012-06-01

    Full Text Available In this paper, a new learning approach based on time-series image information is presented. In order to implementthis new learning technique, a novel time-series input data representation is also defined. This input datarepresentation is based on information obtained by image axis division into boxes. The difference between this newinput data representation and the classical is that this technique is not time-dependent. This new information isimplemented in the new Image-Based Learning Approach (IBLA and by means of a probabilistic mechanism thislearning technique is applied to the interesting problem of time series forecasting. The experimental results indicatethat by using the methodology proposed in this article, it is possible to obtain better results than with the classicaltechniques such as artificial neuronal networks and support vector machines.

  5. A new approach toward object-based change detection

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Object-based change detection has been the hotspot in remote sensing image processing.A new approach toward object-based change detection is proposed.The two different temporal images are unitedly segmented using the mean shift procedure to obtain corresponding objects.Then change detection is implemented based on the integration of corresponding objects’ intensity and texture differences.Experiments are conducted on both panchromatic images and multispectral images and the results show that the integrated measure is robust with respect to illumination changes and noise.Supplementary color detection is conducted to determine whether the color of the unchanged objects changes or not when dealing with multispectral images.Some verification work is carried out to show the accuracy of the proposed approach.

  6. Colorimetry-based edge preservation approach for color image enhancement

    Science.gov (United States)

    Suresh, Merugu; Jain, Kamal

    2016-07-01

    "Subpixel-based downsampling" is an approach that can implicitly enhance perceptible image resolution of a downsampled image by managing subpixel-level representation preferably with individual pixel. A subpixel-level representation for color image sample at edge region and color image representation is focused with the problem of directional filtration based on horizontal and vertical orientations using colorimetric color space with the help of saturation and desaturation pixels. A diagonal tracing algorithm and an edge preserving approach with colorimetric color space were used for color image enhancement. Since, there exist high variations at the edge regions, it could not be considered as constant or zero, and when these variations are random the need to compensate these to minimum value and then process for image representation. Finally, the results of the proposed method show much better image information as compared with traditional direct pixel-based methods with increased luminance and chrominance resolutions.

  7. EVALUATING HUMAN CAPITAL IN A KNOWLEDGE – BASED APPROACH

    Directory of Open Access Journals (Sweden)

    Emanoil MUSCALU

    2014-04-01

    Full Text Available The widespread enthusiasm for a knowledge-based approach to understanding the nature of a business and the possible basis for sustained competitive advantage have renewed interest in human capital evaluation or measurement. While many attempts have been made to develop methods for measuring intellectual capital, none have been widely adopted in the business world. In the knowledge-based organizations, and generally, in the information society, human capital is recognized as the fundamental factor of overall progress, and experts agree that long-term investment in human capital has strong drive-propagation effects at the individual, organizational, national and global level. In this paper, we consider that a knowledge-based approach can offer new possibilities and answers to illustrate the importance of evaluation the human capital and knowledge assets by consistently generating added value in the business world.

  8. Practice-Based Interdisciplinary Approach and Environmental Research

    Directory of Open Access Journals (Sweden)

    Ranjan Kumar Datta

    2017-03-01

    Full Text Available Interdisciplinary researchers and educators, as community members, creators of knowledge, and environmental activists and practitioners, have a responsibility to build a bridge between community practice, academic scholarship, and professional contributions aimed at establishing environmental sustainability. In this paper, I focus on an undervalued area of environmental politics, practices, and often unarticulated assumptions which underlie human–environmental relations. This article challenges interdisciplinary studies that are not connected with practice by reconfiguring the meaning of a community-based, interdisciplinary approach. Drawing from works by Foucault, Latour, and Haraway, this paper first shows how to reconfigure the meaning of an interdisciplinary approach. Second, using Bourdieu and Brightman’s ethnographic studies as a framework, the paper situates practice as central to our efforts to deconstruct and replace current interdisciplinary initiatives with a practice-based approach. Through a practice-based interdisciplinary approach (PIA, environmental educators and researchers gain an awareness of and learn to make an investment in sustainable communities. As teams of environmental researchers practising in the local community, they are meaningfully involved with the community, with each other, and with the environment.

  9. A New Acoustic Emission Sensor Based Gear Fault Detection Approach

    Directory of Open Access Journals (Sweden)

    Junda Zhu

    2013-01-01

    Full Text Available In order to reduce wind energy costs, prognostics and health management (PHM of wind turbine is needed to ensure the reliability and availability of wind turbines. A gearbox is an important component of a wind turbine. Therefore, developing effective gearbox fault detection tools is important to the PHM of wind turbine. In this paper, a new acoustic emission (AE sensor based gear fault detection approach is presented. This approach combines a heterodyne based frequency reduction technique with time synchronous average (TSA and spectrum kurtosis (SK to process AE sensor signals and extract features as condition indictors for gear fault detection. Heterodyne technique commonly used in communication is first employed to preprocess the AE signals before sampling. By heterodyning, the AE signal frequency is down shifted from several hundred kHz to below 50 kHz. This reduced AE signal sampling rate is comparable to that of vibration signals. The presented approach is validated using seeded gear tooth crack fault tests on a notational split torque gearbox. The approach presented in this paper is physics based and the validation results have showed that it could effectively detect the gear faults.

  10. Cerebral computed tomographic angiography scan delay in subarachnoid hemorrhage

    Directory of Open Access Journals (Sweden)

    Lukosevicius Saulius

    2005-01-01

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

  11. Use of digital subtraction angiography for assessment of digital replantatlon

    Institute of Scientific and Technical Information of China (English)

    Liu-hong WANG; Guang-qiang ZHANG

    2012-01-01

    Objective:To assess the blood flow of the proper digital artery using digital subtraction angiography (DSA) in the early stage after replantation.Methods:From January 2006 to October 2010,27 anastomosed arteries in 27 replanted digits were included in the study.The patients included nine males and four females.The patients received DSA at 48 to 96 h after digital replantation.Based on DSA image,the blood flow was classified into normal,slow-running,and flow-stopping types.The patients with normal digital blood flow were given continuous routine treatments; the patients with slow-running flow were given the conservative treatments,such as release of the tight dressings,removal of stitches,keeping warm,the use of massage,and the use of anticoagulants and anti-inflammatory drugs; the patients with flow-stopping received immediate surgical re-exploration.Results:In this series,23 digits in 11 patients showed a normal blood flow,and these digits all survived.In one of 13 patients,two digits which displayed slow-running flow also survived after conservative treatments.In two of 13 patients,two digits showed flow stopping,with one surviving and one failing after re-exploration and arterial revision.Conclusions:The DSA can be used to assess the blood flow of the proper digital artery in the early stage after replantation.It provides essential information for salvaging the replanted finger.

  12. Agent Based Approaches to Engineering Autonomous Space Software

    CERN Document Server

    Dennis, Louise A; Lincoln, Nicholas; Lisitsa, Alexei; Veres, Sandor M

    2010-01-01

    Current approaches to the engineering of space software such as satellite control systems are based around the development of feedback controllers using packages such as MatLab's Simulink toolbox. These provide powerful tools for engineering real time systems that adapt to changes in the environment but are limited when the controller itself needs to be adapted. We are investigating ways in which ideas from temporal logics and agent programming can be integrated with the use of such control systems to provide a more powerful layer of autonomous decision making. This paper will discuss our initial approaches to the engineering of such systems.

  13. Gilmore-Perelomov symmetry based approach to photonic lattices

    CERN Document Server

    Vergara, Liliana Villanueva

    2015-01-01

    We revisit electromagnetic field propagation through tight-binding arrays of coupled photonic waveguides, with properties independent of the propagation distance, and recast it as a symmetry problem. We focus our analysis on photonic lattices with underlying symmetries given by three well-known groups, $SU(2)$, $SU(1,1)$ and Heisenberg-Weyl, to show that disperssion relations, normal states and impulse functions can be constructed following a Gilmore-Perelomov coherent state approach. Furthermore, this symmetry based approach can be followed for each an every lattice with an underlying symmetry given by a dynamical group.

  14. An Approach for Composing Services Based on Environment Ontology

    Directory of Open Access Journals (Sweden)

    Guangjun Cai

    2013-01-01

    Full Text Available Service-oriented computing is revolutionizing the modern computing paradigms with its aim to boost software reuse and enable business agility. Under this paradigm, new services are fabricated by composing available services. The problem arises as how to effectively and efficiently compose heterogeneous services facing the high complexity of service composition. Based on environment ontology, this paper introduces a requirement-driven service composition approach. We propose the algorithms to decompose the requirement, the rules to deduct the relation between services, and the algorithm for composing service. The empirical results and the comparison with other services’ composition methodologies show that this approach is feasible and efficient.

  15. A complexity-based approach to batterer intervention programmes.

    Science.gov (United States)

    Medina-Maldonado, Venus E; Medina-Maldonado, Rossana; Parada-Cores, Germán

    2014-01-01

    This paper was aimed at providing opinion by adopting a complexity-based approach to coordinating nursing science and psychology concerning psycho-educational intervention for batterers regarding their partner or ex-partner. Improving both disciplines' interrelationship should facilitate implementing relevant action, thereby engendering motivation for change in participants and modifying sexist attitudes and beliefs. The document has analyzed the importance of coordinating scientific disciplines' action and defined guidelines for an approach involving intervention as well as highlighting implications for practice and research.

  16. Network Medicine: A Network-based Approach to Human Diseases

    Science.gov (United States)

    Ghiassian, Susan Dina

    With the availability of large-scale data, it is now possible to systematically study the underlying interaction maps of many complex systems in multiple disciplines. Statistical physics has a long and successful history in modeling and characterizing systems with a large number of interacting individuals. Indeed, numerous approaches that were first developed in the context of statistical physics, such as the notion of random walks and diffusion processes, have been applied successfully to study and characterize complex systems in the context of network science. Based on these tools, network science has made important contributions to our understanding of many real-world, self-organizing systems, for example in computer science, sociology and economics. Biological systems are no exception. Indeed, recent studies reflect the necessity of applying statistical and network-based approaches in order to understand complex biological systems, such as cells. In these approaches, a cell is viewed as a complex network consisting of interactions among cellular components, such as genes and proteins. Given the cellular network as a platform, machinery, functionality and failure of a cell can be studied with network-based approaches, a field known as systems biology. Here, we apply network-based approaches to explore human diseases and their associated genes within the cellular network. This dissertation is divided in three parts: (i) A systematic analysis of the connectivity patterns among disease proteins within the cellular network. The quantification of these patterns inspires the design of an algorithm which predicts a disease-specific subnetwork containing yet unknown disease associated proteins. (ii) We apply the introduced algorithm to explore the common underlying mechanism of many complex diseases. We detect a subnetwork from which inflammatory processes initiate and result in many autoimmune diseases. (iii) The last chapter of this dissertation describes the

  17. Diagnostic accuracy of CT angiography in acute gastrointestinal bleeding.

    Science.gov (United States)

    Chua, A E; Ridley, L J

    2008-08-01

    The aim of the study was to carry out a systematic review determining the accuracy of CT angiography in the diagnosis of acute gastrointestinal bleeding. A search of published work in Medline and manual searching of reference lists of articles was conducted. Studies were included if they compared CT angiography to a reference standard of upper gastrointestinal endoscopy, colonoscopy, angiography or surgery in the diagnosis of acute gastrointestinal bleeding. Eight published studies evaluating 129 patients were included. Data were used to form 2 x 2 tables. Computed tomography angiography showed pooled sensitivity of 86% (95% confidence interval 78-92%) and specificity of 95% (95% confidence interval 76-100%), without showing significant heterogeneity (chi(2) = 3.5, P = 0.6) and (chi(2) = 5.4, P = 0.6), respectively. Summary receiver operating characteristic analysis showed an area under the curve of 0.93. Computed tomography angiography is accurate in the diagnosis of acute gastrointestinal bleeding and can show the precise location and aetiology of bleeding, thereby directing further management. Strong recommendations for use of CT cannot be made from this review because of the methodological limitations and further large prospective studies are needed to define the role of CT in acute gastrointestinal bleeding.

  18. Cranio-orbito-zygomatic approach for a previously coiled/recurrent giant MCA aneurysm in a hybrid angio/OR suite.

    Science.gov (United States)

    Arko, Leopold; Quach, Eric; Sukul, Vishad; Desai, Anuj; Gassie, Kelly; Erkmen, Kadir

    2015-07-01

    We present surgical clipping of a giant middle cerebral artery aneurysm. The patient is a 64-year-old woman who suffered subarachnoid hemorrhage in 2005. She was treated with coiling of the aneurysm at an outside institution. She presented to our clinic with headaches and was found on angiography to have giant recurrence of the aneurysm. To allow adequate exposure for clipping, we performed the surgery through a cranio-orbito-zygomatic (COZ) skull base approach, which is demonstrated. The surgery was performed in an operating room/angiography hybrid suite allowing for high quality intraoperative angiography. The technique and room flow are also demonstrated. The video can be found here: http://youtu.be/eePcyOMi85M.

  19. A novel image fusion approach based on compressive sensing

    Science.gov (United States)

    Yin, Hongpeng; Liu, Zhaodong; Fang, Bin; Li, Yanxia

    2015-11-01

    Image fusion can integrate complementary and relevant information of source images captured by multiple sensors into a unitary synthetic image. The compressive sensing-based (CS) fusion approach can greatly reduce the processing speed and guarantee the quality of the fused image by integrating fewer non-zero coefficients. However, there are two main limitations in the conventional CS-based fusion approach. Firstly, directly fusing sensing measurements may bring greater uncertain results with high reconstruction error. Secondly, using single fusion rule may result in the problems of blocking artifacts and poor fidelity. In this paper, a novel image fusion approach based on CS is proposed to solve those problems. The non-subsampled contourlet transform (NSCT) method is utilized to decompose the source images. The dual-layer Pulse Coupled Neural Network (PCNN) model is used to integrate low-pass subbands; while an edge-retention based fusion rule is proposed to fuse high-pass subbands. The sparse coefficients are fused before being measured by Gaussian matrix. The fused image is accurately reconstructed by Compressive Sampling Matched Pursuit algorithm (CoSaMP). Experimental results demonstrate that the fused image contains abundant detailed contents and preserves the saliency structure. These also indicate that our proposed method achieves better visual quality than the current state-of-the-art methods.

  20. An engineering based approach for hydraulic computations in river flows

    Science.gov (United States)

    Di Francesco, S.; Biscarini, C.; Pierleoni, A.; Manciola, P.

    2016-06-01

    This paper presents an engineering based approach for hydraulic risk evaluation. The aim of the research is to identify a criteria for the choice of the simplest and appropriate model to use in different scenarios varying the characteristics of main river channel. The complete flow field, generally expressed in terms of pressure, velocities, accelerations can be described through a three dimensional approach that consider all the flow properties varying in all directions. In many practical applications for river flow studies, however, the greatest changes occur only in two dimensions or even only in one. In these cases the use of simplified approaches can lead to accurate results, with easy to build and faster simulations. The study has been conducted taking in account a dimensionless parameter of channels (ratio of curvature radius and width of the channel (R/B).

  1. MDA based-approach for UML Models Complete Comparison

    CERN Document Server

    Chaouni, Samia Benabdellah; Mouline, Salma

    2011-01-01

    If a modeling task is distributed, it will frequently be necessary to integrate models developed by different team members. Problems occur in the models integration step and particularly, in the comparison phase of the integration. This issue had been discussed in several domains and various models. However, previous approaches have not correctly handled the semantic comparison. In the current paper, we provide a MDA-based approach for models comparison which aims at comparing UML models. We develop an hybrid approach which takes into account syntactic, semantic and structural comparison aspects. For this purpose, we use the domain ontology as well as other resources such as dictionaries. We propose a decision support system which permits the user to validate (or not) correspondences extracted in the comparison phase. For implementation, we propose an extension of the generic correspondence metamodel AMW in order to transform UML models to the correspondence model.

  2. [A complexity-based approach to zoonoses in Colombia].

    Science.gov (United States)

    Agudelo-Suárez, Angela N

    2012-01-01

    The present reflection was aimed at making a contribution towards improving control policy and programs integrality and efficacy in an attempt to answer the following question, "How can understanding zoonoses in Colombia be approached from a complexity-based approach?" The first part of this article examines zoonoses as a complex problem and the reiterated tendency of control policy and programs to deal with them as a simple problem, involving unidisciplinary and reductionist responses. The current status of complexity is synthesized as a paradigm, as are the advantages of using it in analysis and formulating policy and interventions. Possible fields of work are proposed for development when approaching zoonoses in Colombia from a complexity science viewpoint.

  3. A fuzzy behaviorist approach to sensor-based robot control

    Energy Technology Data Exchange (ETDEWEB)

    Pin, F.G.

    1996-05-01

    Sensor-based operation of autonomous robots in unstructured and/or outdoor environments has revealed to be an extremely challenging problem, mainly because of the difficulties encountered when attempting to represent the many uncertainties which are always present in the real world. These uncertainties are primarily due to sensor imprecisions and unpredictability of the environment, i.e., lack of full knowledge of the environment characteristics and dynamics. An approach. which we have named the {open_quotes}Fuzzy Behaviorist Approach{close_quotes} (FBA) is proposed in an attempt to remedy some of these difficulties. This approach is based on the representation of the system`s uncertainties using Fuzzy Set Theory-based approximations and on the representation of the reasoning and control schemes as sets of elemental behaviors. Using the FBA, a formalism for rule base development and an automated generator of fuzzy rules have been developed. This automated system can automatically construct the set of membership functions corresponding to fuzzy behaviors. Once these have been expressed in qualitative terms by the user. The system also checks for completeness of the rule base and for non-redundancy of the rules (which has traditionally been a major hurdle in rule base development). Two major conceptual features, the suppression and inhibition mechanisms which allow to express a dominance between behaviors are discussed in detail. Some experimental results obtained with the automated fuzzy, rule generator applied to the domain of sensor-based navigation in aprion unknown environments. using one of our autonomous test-bed robots as well as a real car in outdoor environments, are then reviewed and discussed to illustrate the feasibility of large-scale automatic fuzzy rule generation using the {open_quotes}Fuzzy Behaviorist{close_quotes} concepts.

  4. A microfabrication-based approach to quantitative isothermal titration calorimetry.

    Science.gov (United States)

    Wang, Bin; Jia, Yuan; Lin, Qiao

    2016-04-15

    Isothermal titration calorimetry (ITC) directly measures heat evolved in a chemical reaction to determine equilibrium binding properties of biomolecular systems. Conventional ITC instruments are expensive, use complicated design and construction, and require long analysis times. Microfabricated calorimetric devices are promising, although they have yet to allow accurate, quantitative ITC measurements of biochemical reactions. This paper presents a microfabrication-based approach to integrated, quantitative ITC characterization of biomolecular interactions. The approach integrates microfabricated differential calorimetric sensors with microfluidic titration. Biomolecules and reagents are introduced at each of a series of molar ratios, mixed, and allowed to react. The reaction thermal power is differentially measured, and used to determine the thermodynamic profile of the biomolecular interactions. Implemented in a microdevice featuring thermally isolated, well-defined reaction volumes with minimized fluid evaporation as well as highly sensitive thermoelectric sensing, the approach enables accurate and quantitative ITC measurements of protein-ligand interactions under different isothermal conditions. Using the approach, we demonstrate ITC characterization of the binding of 18-Crown-6 with barium chloride, and the binding of ribonuclease A with cytidine 2'-monophosphate within reaction volumes of approximately 0.7 µL and at concentrations down to 2mM. For each binding system, the ITC measurements were completed with considerably reduced analysis times and material consumption, and yielded a complete thermodynamic profile of the molecular interaction in agreement with published data. This demonstrates the potential usefulness of our approach for biomolecular characterization in biomedical applications.

  5. [Clinical study with angiography system using a flat panel detecter].

    Science.gov (United States)

    Ichida, Takao; Okusako, Kenji; Yokoyama, Kouji; Shougaki, Masachika; Ogawa, Takayoshi; Kawahata, Hideki; Nasu, Takehisa; Hosogai, Minoru; Okuyama, Kazuo; Hatagawa, Masakatsu

    2004-08-01

    We have been using an X-ray angiography system that incorporates a flat panel detector (FPD) since December 2001. This system is equipped with the scintillator-type FPD PaxScan 4030A from Varian Medical Systems, and for objective comparison of the image intensifier (I.I.) and FPD, the system is constructed so that these detectors can be used alternatively. Using this system and other X-ray angiography systems, visual studies have been conducted on the digital subtraction angiography (DSA) images acquired by FPD and I.I. We have found from the clinical images that the FPD is superior to the I.I. in depiction of fine blood vessels as well as of physical characteristics. Fluoroscopy images acquired by the FPD were not entirely satisfactory, however the improvement made in its performance now permits equal use of the FPD and I.I. systems.

  6. Multidetector CT angiography of renal vasculature: normal anatomy and variants

    Energy Technology Data Exchange (ETDEWEB)

    Tuerkvatan, Aysel; Oezdemir, Mustafa; Cumhur, Turhan; Oelcer, Tuelay [Tuerkiye Yueksek ihtisas Hospital, Department of Radiology, Sihhiye, Ankara (Turkey)

    2009-01-15

    Knowledge of the variations in renal vascular anatomy is important before laparoscopic donor or partial nephrectomy and vascular reconstruction for renal artery stenosis or abdominal aortic aneurysm. Recently, multidetector computed tomographic (MDCT) angiography has become a principal imaging investigation for assessment of the renal vasculature and has challenged the role of conventional angiography. It is an excellent imaging technique because it is a fast and non-invasive tool that provides highly accurate and detailed evaluation of normal renal vascular anatomy and variants. The number, size and course of the renal arteries and veins are easily identified by MDCT angiography. The purpose of this pictorial essay is to illustrate MDCT angiographic appearance of normal anatomy and common variants of the renal vasculature. (orig.)

  7. English to Sanskrit Machine Translation Using Transfer Based approach

    Science.gov (United States)

    Pathak, Ganesh R.; Godse, Sachin P.

    2010-11-01

    Translation is one of the needs of global society for communicating thoughts and ideas of one country with other country. Translation is the process of interpretation of text meaning and subsequent production of equivalent text, also called as communicating same meaning (message) in another language. In this paper we gave detail information on how to convert source language text in to target language text using Transfer Based Approach for machine translation. Here we implemented English to Sanskrit machine translator using transfer based approach. English is global language used for business and communication but large amount of population in India is not using and understand the English. Sanskrit is ancient language of India most of the languages in India are derived from Sanskrit. Sanskrit can be act as an intermediate language for multilingual translation.

  8. Proposed Representation Approach Based on Description Logics Formalism

    Directory of Open Access Journals (Sweden)

    Yasser Yahiaoui

    2016-05-01

    Full Text Available The most familiar concept in Artificial intelligence is the knowledges representation. It aims to find explicit symbolization covering all semantic aspects of knowledge, and to make possible the use of this representation to produce an intelligent behavior like reasoning. The most important constraint is the usability of the representation; it’s why the structures used must be well defined to facilitate manipulation for reasoning algorithms which leads to facilitate their implementation. In this paper we propose a new approach based on the description logics formalism for the goal of simplification of description logics system implementation. This approach can reduce the complexity of reasoning Algorithm by the vectorisation of concept definition based on the subsumption hierarchy.

  9. A Computationally Based Approach to Homogenizing Advanced Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jablonski, P D; Cowen, C J

    2011-02-27

    We have developed a computationally based approach to optimizing the homogenization heat treatment of complex alloys. The Scheil module within the Thermo-Calc software is used to predict the as-cast segregation present within alloys, and DICTRA (Diffusion Controlled TRAnsformations) is used to model the homogenization kinetics as a function of time, temperature and microstructural scale. We will discuss this approach as it is applied to both Ni based superalloys as well as the more complex (computationally) case of alloys that solidify with more than one matrix phase as a result of segregation. Such is the case typically observed in martensitic steels. With these alloys it is doubly important to homogenize them correctly, especially at the laboratory scale, since they are austenitic at high temperature and thus constituent elements will diffuse slowly. The computationally designed heat treatment and the subsequent verification real castings are presented.

  10. A NEW ADMISSION CONTROL APPROACH BASED ON PREDICTION

    Institute of Scientific and Technical Information of China (English)

    Lu Kaining; Jin Zhigang; Zou Jun

    2002-01-01

    Admission control plays an important role in providing QoS to network users. Motivated by the measurement-based admission control algorithm, this letter proposed a new admission control approach for integrated service packet network based on traffic prediction. In the letter, FARIMA(p, d, q) models in the admission control algorithm is deployed. A method to simplify the FARIMA model fitting procedure and hence to reduce the time of traffic modeling and prediction is suggested. The feasibility-study experiments show that FARIMA models which have less number of parameters can be used to model and predict actual traffic on quite a large time scale. Simulation results validate the promising approach.

  11. Data Warehouse Requirements Analysis Framework: Business-Object Based Approach

    Directory of Open Access Journals (Sweden)

    Anirban Sarkar

    2012-01-01

    Full Text Available Detailed requirements analysis plays a key role towards the design of successful Data Warehouse (DW system. The requirements analysis specifications are used as the prime input for the construction of conceptual level multidimensional data model. This paper has proposed a Business Object based requirements analysis framework for DW system which is supported with abstraction mechanism and reuse capability. It also facilitate the stepwise mapping of requirements descriptions into high level design components of graph semantic based conceptual level object oriented multidimensional data model. The proposed framework starts with the identification of the analytical requirements using business process driven approach and finally refine the requirements in further detail to map into the conceptual level DW design model using either Demand-driven of Mixed-driven approach for DW requirements analysi

  12. Knowledge Management Approaches in Portal-Based Collaborative

    Directory of Open Access Journals (Sweden)

    Mihaela I. MUNTEAN

    2009-01-01

    Full Text Available Collaboration involves a different approach to business – focused on managing business relationships between people, within or without groups, and within and between organizations. Collaborative enterprises differ from other business in a number of ways and collaborative working needs to be simultaneously a business philosophy, strategy and operational working. Effective collaboration unlocks the potential of the collective knowledge and intellectual capital of the organization and its networks of business partners, suppliers and customers. At the core of true collaboration is the ability to share and catalogue knowledge, ideas, standards, best practices, and lessons learned and to be able to retrieve that knowledge from anywhere at any time. Knowledge management is not a goal by itself. Businesses don't exist with the purpose of spreading and advancing knowledge, they exist for selling competitive products and services of high quality. Based on these considerations, we propose some knowledge management approaches for portal-based collaborative environments.

  13. An SQL-based approach to physics analysis

    Science.gov (United States)

    Limper, Maaike, Dr

    2014-06-01

    As part of the CERN openlab collaboration a study was made into the possibility of performing analysis of the data collected by the experiments at the Large Hadron Collider (LHC) through SQL-queries on data stored in a relational database. Currently LHC physics analysis is done using data stored in centrally produced "ROOT-ntuple" files that are distributed through the LHC computing grid. The SQL-based approach to LHC physics analysis presented in this paper allows calculations in the analysis to be done at the database and can make use of the database's in-built parallelism features. Using this approach it was possible to reproduce results for several physics analysis benchmarks. The study shows the capability of the database to handle complex analysis tasks but also illustrates the limits of using row-based storage for storing physics analysis data, as performance was limited by the I/O read speed of the system.

  14. CT coronary angiography versus conventional invasive coronary angiography. The view of the referring physician

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, Martin H. [Charite - Universitaetsmedizin Berlin (Germany). Dept. of Radiology; Universitaetsspital Bern (Switzerland). Dept. fuer Diagnostische, Interventionelle und Paediatrische Radiologie; Zimmermann, E.; Hamm, B. [Charite - Universitaetsmedizin Berlin (Germany). Dept. of Radiology; Dewey, M.

    2014-12-15

    Assessment of experience gained by local referring physicians with the procedure of coronary computed tomographic angiography (CCTA) in the everyday clinical routine. A 25-item questionnaire was sent to 179 physicians, who together had referred a total of 1986 patients for CCTA. They were asked about their experience to date with CCTA, the indications for coronary imaging, and their practice in referring patients for noninvasive CCTA or invasive catheter angiography. 53 questionnaires (30%) were assessable, corresponding to more than 72% of the patients referred. Of the referring physicians who responded, 94% saw a concrete advantage of CCTA in the treatment of patients, whereby 87% were 'satisfied' or 'very satisfied' with the reporting. For excluding coronary heart disease (CHD) where there was a low pre-test probability of disease, the physicians considered CCTA to be superior to conventional coronary diagnosis (4.2 on a scale of 1-5) and vice versa for acute coronary syndrome (1.6 of 5). The main reasons for unsuitability of CCTA for CT diagnosis were claustrophobia and the absence of a sinus rhythm. The level of exposure to radiation in CCTA was estimated correctly by only 42% of the referring physicians. 90% of the physicians reported that their patients evaluated their coronary CT overall as 'positive' or 'neutral', while 87% of the physicians whose patients had undergone both procedures reported that the patients had experienced CCTA as the less disagreeable of the two. CCTA is accepted by the referring physicians as an alternative imaging procedure for the exclusion of CHD and received a predominantly positive assessment from both the referring physicians and the patients.

  15. Diabetic Macular Ischemia Diagnosis: Comparison between Optical Coherence Tomography Angiography and Fluorescein Angiography

    Directory of Open Access Journals (Sweden)

    Jose Mauricio Botto de Barros Garcia

    2016-01-01

    Full Text Available Purpose. To compare fluorescein angiography (FA and optical coherence tomography angiography (OCTA images of foveal avascular zone (FAZ in patients with diabetic retinopathy (DR with and without diabetic macular ischemia (DMI. Methods. The Wilcoxon signed-rank test was used to compare area measurements and p values of <0.05 were considered statistically significant. FA and OCTA images were independently graded by 2 observers that reached agreement regarding quantitative DMI according established protocols. The ischemic area was divided into “large” macular ischemia (superior to 0.32 mm2 and “small” (inferior to 0.32 mm2 groups. Quantitative analyses of the FAZ were performed using custom software. Results. Thirty-four eyes from 34 diabetic patients were enrolled. Subjects with DMI presented a mean area on FA and OCTA of 0.68 ± 0.53 mm2 and 0.58 ± 0.35 mm2, respectively (p=0.1374. Patients without DMI presented a mean area on FA and OCTA of 0.19 ± 0.67 mm2 and 0.20 ± 0.79 mm2, respectively (p=0.9594. The ICC for the FAZ measurements between the 2 observers on FA and OCTA was 0.96 and 0.92, respectively. Conclusion. OCTA represents a novel technique for the diagnosis of DMI and it may become an alternative to FA for this purpose.

  16. A pattern-based approach to elementary algebra

    OpenAIRE

    Strømskag, Heidi

    2015-01-01

    International audience; With a focus on epistemology, this paper discusses what pattern generalisation as an algebraic activity involves. Further, it presents a review of empirical studies where a pattern-based approach is used to teach algebra. This shows that students' problems with establishing algebraic rules from patterns and tables can be explained by: 1) difficulties caused by students' use of invalid methods to identify explicit formulae; 2) difficulties caused by students' tendency t...

  17. Improved Approach Based on SVM for License Plate Character Recognition

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-hua; WANG Xiao-guang

    2005-01-01

    An improved approach based on support vector machine (SVM) called the center distance ratio method is presented for license plate character recognition. First the support vectors are pre-extracted. A minimal set called the margin vector set, which contains all support vectors, is extracted. These margin vectors compose new training data and construct the classifier by using the general SVM optimized. The experimental results show that the improved SVM method does well at correct rate and training speed.

  18. A belief revision approach for argumentation-based negotiation agents

    Directory of Open Access Journals (Sweden)

    Pilotti Pablo

    2015-09-01

    Full Text Available Negotiation is an interaction that happens in multi-agent systems when agents have conflicting objectives and must look for an acceptable agreement. A typical negotiating situation involves two agents that cannot reach their goals by themselves because they do not have some resources they need or they do not know how to use them to reach their goals. Therefore, they must start a negotiation dialogue, taking also into account that they might have incomplete or wrong beliefs about the other agent’s goals and resources. This article presents a negotiating agent model based on argumentation, which is used by the agents to reason on how to exchange resources and knowledge in order to achieve their goals. Agents that negotiate have incomplete beliefs about the others, so that the exchange of arguments gives them information that makes it possible to update their beliefs. In order to formalize their proposals in a negotiation setting, the agents must be able to generate, select and evaluate arguments associated with such offers, updating their mental state accordingly. In our approach, we will focus on an argumentation-based negotiation model between two cooperative agents. The arguments generation and interpretation process is based on belief change operations (expansions, contractions and revisions, and the selection process is a based on a strategy. This approach is presented through a high-level algorithm implemented in logic programming. We show various theoretical properties associated with this approach, which have been formalized and proved using Coq, a formal proof management system. We also illustrate, through a case study, the applicability of our approach in order to solve a slightly modified version of the well-known home improvement agents problem. Moreover, we present various simulations that allow assessing the impact of belief revision on the negotiation process.

  19. Flow-based approach for holistic factory engineering and design

    OpenAIRE

    Constantinescu, C.; Westkämper, E.

    2010-01-01

    The engineering of future factories requires digital tools along life cycle phases from investment planning to ramp-up. Manufacturers need scientific-based integrated highly dynamic data management systems for the participative and integrated factory planning. The paper presents a new approach for the continuously integrated product design, factory and process planning, through a service-oriented architecture for the implementation of digital factory tools. A first prototype of the digital fa...

  20. A New Approach to Coding in Content Based MANETs

    OpenAIRE

    Joy, Joshua; Yu, Yu-Ting; Perez, Victor; Lu, Dennis; Gerla, Mario

    2015-01-01

    In content-based mobile ad hoc networks (CB-MANETs), random linear network coding (NC) can be used to reliably disseminate large files under intermittent connectivity. Conventional NC involves random unrestricted coding at intermediate nodes. This however is vulnerable to pollution attacks. To avoid attacks, a brute force approach is to restrict the mixing at the source. However, source restricted NC generally reduces the robustness of the code in the face of errors, losses and mobility induc...

  1. A Knowledge—Based Approach to Program Synthesis from Examples

    Institute of Scientific and Technical Information of China (English)

    朱鸿; 金凌紫

    1991-01-01

    This paper proposes an approach to synthesize functional programs of Backus' FP system[1,2] from input/output instances.Based on a theory of orthogonal expansion of programs3[,4],the task of program synthesis is expressed in program equations,and fulfilled by solving them according to the knowledge about the equivalence between programs.Some general knowledge of solving program equations with a number of examples are given in the paper.

  2. Performance Analysis of STFT Based Timing Approach to OFDM Systems

    Institute of Scientific and Technical Information of China (English)

    KUANG Yu-jun; TENG Yong; YIN Chang-chuan; HAO Jian-jun; YUE Guang-xin

    2003-01-01

    This paper mainly focuses on performance analysis of the previously proposed STFT based 2-D timing approach to OFDM systems and presents simulations results of its performance in AWGN and multipath fading environment and its robustness against the duration of Channel Impulse Response (CIR) and frequency offset. Simulation results suggest that a revised version of Short-Time Fourier Transform (STFT) can be used to greatly reduce computational complexity, especially at higher SNR.

  3. Java Applications Development Based on Component and Metacomponent Approach

    OpenAIRE

    Danijel Radošević; Mario Konecki; Tihomir Orehovački

    2008-01-01

    Component based modeling offers new and improved approach to design, construction, implementation and evolution of software applications development. This kind of software applications development is usually represented by appropriate component model/diagram. UML, for example, offers component diagram for representation of this kind of model. On the other hand, metacomponents usage offers some new features which hardly could be achieved by using generic components. Firstly, implementation of ...

  4. Pseudoaneurysm after pancreatoduodenectomy: diagnosis and embolization on angiography

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jun Yong [Kangwon National University College of Medicine, Chuncheon (Korea, Republic of); Lee, Sang Hyun; Kim, Sam Soo; Han, Heon; Chung, Hye Won [Seoul City Boramae Hospital, Seoul (Korea, Republic of); Youn, Byung Jae; Han, Joon Koo; Choi, Byung Ihn; Chung, Jin Wook; Park, Jae Hyung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2002-08-01

    To evaluate the efficacy of angiography in the diagnosis and treatment of pseudoaneurysm manifesting arterial hemorrhage as a significant complication following pancreatoduodenectomy. For 51 months, of a total of 298 patients who had undergone pancreatoduodenectomy, 19 patients (6.4%) developed clinically significant hemorrhage and nine patients proved to have a pseudoaneurysm of angiography. These nine patients (3.0%) were managed by transcatheter arterial embolization. We analyzed clinical feature, angiography findings and hemostatic effect of embolization retrospectively. In nine patients (3.0%), pseudoaneurysm was diagnosed on angiography (common hepatic artery in four, gastroduodenal artery in three, proper hepatic artery in one, and left gastroepoploic artery in on patient). The size ranged from 0.3 cm to 6.5 cm (mean 1.9 cm). And extravasation was noted in five patients (55.6%). The remained ten patients showed no evidence of bleeding on angiography. Those who manifested as early bleeding (within two weeks) or delayed bleeding ( later than two weeks) were five and four patients respectively. Before the onset of major bleeding, among the nine pseudoaneurysm patients, seven patients (77.8%) had experienced percutaneous drainage due to intra-abdominal fluid collection with or without abscess resulting from anastomotic leak, and all nine patients had preliminary minor bleeding. The angiogram demonstrated an exact site of bleeding as a pseucoaneurysm followed by transcatheter arterial embolization (microcoil in eight patients, gelfoam in one) and achieved complete hemostasis yielding a success rate of 100%. Overall, no patients experienced complications related directly to the transcatheter arterial embolization technique. During the follow-up period (72-1, 336days, mean 640), no recurrence of bleeding was note. Although pseudoaneurysm is a rare complication, it is important as a cause of hemorrhage after pancreatoduodenectomy. Angiography followed by

  5. Evaluation of magnetic resonance angiography in detection of gastric varices

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Takahiro; Yamazaki, Katsu; Toyota, Jouji; Karino, Yoshiyasu; Ohmura, Takumi; Suga, Toshihiro [Sapporo Kosei General Hospital (Japan)

    1999-06-01

    We evaluated the detection of gastric varices, inflowing blood vessels to gastric varices, and outflowing blood vessels from gastric varices via magnetic resonance (MR) angiography in 31 patients with gastric varices. Twenty-four patients had F{sub 2} type varices and 7 had F{sub 3} type, classified according to the Japanese Research Society for Portal Hypertension. Seventeen patients had cardiofornical varices, and 14 had fundal varices. All patients were examined with an MR system operating at 1.5 T. MR angiography was performed using the two-dimensional time-of-flight method. With MR angiography, the imaging of gastric varices was clearly delineated in 28 of the 31 patients (90.3%). From the images of MR angiography, flow direction itself cannot be determined. The outflowing blood vessels of gastric varices were reported to be the gastro-renal shunt and the subphrenic vein, and angiographic findings have shown the inflowing blood vessels to be the left gastric vein (LGV), the short gastric vein (SGV), and the posterior gastric vein (PGV). In 25 of the 31 patients (80.7%), the outflowing blood vessels from gastric varices were detected (gastro-renal shunt in 24; subphrenic vein in 1). MR angiography provided clear images of the inflowing blood vessels to gastric varices in 18 of the 31 patients (58.1%). These inflowing vessels were categorized as SGV in 7 patients, LGV in 5, LGV and SGV in 4, and LGV and PGV in 2. We suggest that MR angiography be used as a routine method for detecting and diagnosing collateral veins in patients with gastric varices. (author)

  6. Clinical significance of balloon dilatation angiography during cerebral venous sinus stenosis stenting

    Directory of Open Access Journals (Sweden)

    Xiang-yu CAO

    2016-12-01

    Full Text Available Objective To explore the clinical significance of balloon dilatation angiography during cerebral venous sinus stenosis stenting to predict the reflux of perforator veins after operation. Methods A total of 93 patients (including 51 with cerebral venous sinus stenosis and intracranial hypertension and 42 with intractable pulsatile tinnitus caused by cerebral venous sinus stenosis who were treated by stent implantation were analyzed retrospectively. Among those patients, the diameter of transverse and sigmoid sinuses of 63 cases were measured based on angiography, and stent was selected according to the measurement result. The other 30 cases were given angiography on ipsilateral carotid artery or vertebral artery when the balloon was dilated in the venous sinus to confirm the reflux of perforator veins. If the venous reflux decreased in the angiography, stent with diameter 1-2 mm less than that of venous sinus could be selected.  Results The success rate of stenting was 100% (93/93. In 63 cases, 45 cases were planted 9 mm × 40 mm stents, 15 were planted 8 mm × 40 mm stents, 3 were planted 7 mm × 40 mm stents. The average diameter of stents was (8.67 ± 0.68 mm. There were 11 cases (17.46% with slow perforator venous reflux after operation. In the other 30 cases, 3 cases were planted 8 mm × 40 mm stents, 11 were planted 7 mm × 40 mm stents, and 16 were planted 6 mm × 40 mm stents. The average diameter of stents was (7.57 ± 0.67 mm. There was only one case (3.33% with slow perforator venous reflux after operation. The difference of stent diameter between 2 groups was statistically significant (t = 15.632, P = 0.001. The occurrence rate of perforator vein occlusion after operation between 2 groups was significantly different (adjusted χ 2 = 60.065, P = 0.001.  Conclusions Perforator vein occlusion after cerebral venous sinus stenting is common complication. Balloon dilatation angiography could predict the possibility of perforator vein

  7. Science based integrated approach to advanced nuclear fuel development - vision, approach, and overview

    Energy Technology Data Exchange (ETDEWEB)

    Unal, Cetin [Los Alamos National Laboratory; Pasamehmetoglu, Kemal [IDAHO NATIONAL LAB; Carmack, Jon [IDAHO NATIONAL LAB

    2010-01-01

    Advancing the performance of Light Water Reactors, Advanced Nuclear Fuel Cycles, and Advanced Rcactors, such as the Next Generation Nuclear Power Plants, requires enhancing our fundamental understanding of fuel and materials behavior under irradiation. The capability to accurately model the nuclear fuel systems is critical. In order to understand specific aspects of the nuclear fuel, fully coupled fuel simulation codes are required to achieve licensing of specific nuclear fuel designs for operation. The backbone of these codes, models, and simulations is a fundamental understanding and predictive capability for simulating the phase and microstructural behavior of the nuclear fuel system materials and matrices. The purpose of this paper is to identify the modeling and simulation approach in order to deliver predictive tools for advanced fuels development. The coordination between experimental nuclear fuel design, development technical experts, and computational fuel modeling and simulation technical experts is a critical aspect of the approach and naturally leads to an integrated, goal-oriented science-based R & D approach and strengthens both the experimental and computational efforts. The Advanced Fuels Campaign (AFC) and Nuclear Energy Advanced Modeling and Simulation (NEAMS) Fuels Integrated Performance and Safety Code (IPSC) are working together to determine experimental data and modeling needs. The primary objective of the NEAMS fuels IPSC project is to deliver a coupled, three-dimensional, predictive computational platform for modeling the fabrication and both normal and abnormal operation of nuclear fuel pins and assemblies, applicable to both existing and future reactor fuel designs. The science based program is pursuing the development of an integrated multi-scale and multi-physics modeling and simulation platform for nuclear fuels. This overview paper discusses the vision, goals and approaches how to develop and implement the new approach.

  8. A mindfulness-based approach to the treatment of insomnia.

    Science.gov (United States)

    Ong, Jason; Sholtes, David

    2010-11-01

    Mindfulness meditation has emerged as a novel approach to emotion regulation and stress reduction that has several health benefits. Preliminary work has been conducted on mindfulness-based therapy for insomnia (MBT-I), a meditation-based program for individuals suffering from chronic sleep disturbance. This treatment integrates behavioral treatments for insomnia with the principles and practices of mindfulness meditation. A case illustration of a chronic insomnia sufferer demonstrates the application of mindfulness principles for developing adaptive ways of working with the nocturnal symptoms and waking consequences of chronic insomnia.

  9. The FPGA based L1 track finding Tracklet approach

    Science.gov (United States)

    Kyriacou, Savvas; CMS Collaboration

    2017-01-01

    The High Luminosity upgraded LHC is expected to deliver proton-proton collisions per 25ns with an estimated 140-200 pile up interactions per bunch crossing. Ultrafast track finding is vital for handling trigger rates in such conditions. An FPGA based road search algorithm is developed, the Tracklet approach one of a few currently under consideration, for the CMS L1 trigger system. Based on low/high transverse momentum track discrimination and designed for the HL upgraded outer tracker, the algorithm achieves microsecond scale track reconstruction in the expected high track multiplicity environment. The Tracklet method overview, implementation, hardware demonstrator and performance results are presented and discussed.

  10. Assessment of coronary artery disease using coronary computed tomography angiography and biochemical markers

    Institute of Scientific and Technical Information of China (English)

    Gitsios; Gitsioudis; Hugo; A; Katus; Grigorios; Korosoglou

    2014-01-01

    Chronic inflammatory mechanisms in the arterial wall lead to atherosclerosis,and include endothelial cell damage,inflammation,apoptosis,lipoprotein deposition,calcification and fibrosis.Cardiac computed tomography angiography(CCTA)has been shown to be a promising tool for non-invasive assessment of theses specific compositional and structural changes in coronary arteries.This review focuses on the technical background of CCTA-based quantitative plaque characterization.Furthermore,we discuss the available evidence for CCTA-based plaque characterization and the potential role of CCTA for risk stratification of patients with coronary artery disease.

  11. A Model-Based Prognostics Approach Applied to Pneumatic Valves

    Science.gov (United States)

    Daigle, Matthew J.; Goebel, Kai

    2011-01-01

    Within the area of systems health management, the task of prognostics centers on predicting when components will fail. Model-based prognostics exploits domain knowledge of the system, its components, and how they fail by casting the underlying physical phenomena in a physics-based model that is derived from first principles. Uncertainty cannot be avoided in prediction, therefore, algorithms are employed that help in managing these uncertainties. The particle filtering algorithm has become a popular choice for model-based prognostics due to its wide applicability, ease of implementation, and support for uncertainty management. We develop a general model-based prognostics methodology within a robust probabilistic framework using particle filters. As a case study, we consider a pneumatic valve from the Space Shuttle cryogenic refueling system. We develop a detailed physics-based model of the pneumatic valve, and perform comprehensive simulation experiments to illustrate our prognostics approach and evaluate its effectiveness and robustness. The approach is demonstrated using historical pneumatic valve data from the refueling system.

  12. A Model-based Prognostics Approach Applied to Pneumatic Valves

    Directory of Open Access Journals (Sweden)

    Matthew J. Daigle

    2011-01-01

    Full Text Available Within the area of systems health management, the task of prognostics centers on predicting when components will fail. Model-based prognostics exploits domain knowledge of the system, its components, and how they fail by casting the underlying physical phenomena in a physics-based model that is derived from first principles. Uncertainty cannot be avoided in prediction, therefore, algorithms are employed that help in managing these uncertainties. The particle filtering algorithm has become a popular choice for model-based prognostics due to its wide applicability, ease of implementation, and support for uncertainty management. We develop a general model-based prognostics methodology within a robust probabilistic framework using particle filters. As a case study, we consider a pneumatic valve from the Space Shuttle cryogenic refueling system. We develop a detailed physics-based model of the pneumatic valve, and perform comprehensive simulation experiments to illustrate our prognostics approach and evaluate its effectiveness and robustness. The approach is demonstrated using historical pneumatic valve data from the refueling system.

  13. Reversible Circuit Synthesis Using a Cycle-Based Approach

    CERN Document Server

    Saeedi, Mehdi; Sedighi, Mehdi; Sasanian, Zahra

    2010-01-01

    Reversible logic has applications in various research areas including signal processing, cryptography and quantum computation. In this paper, direct NCT-based synthesis of a given $k$-cycle in a cycle-based synthesis scenario is examined. To this end, a set of seven building blocks is proposed that reveals the potential of direct synthesis of a given permutation to reduce both quantum cost and average runtime. To synthesize a given large cycle, we propose a decomposition algorithm to extract the suggested building blocks from the input specification. Then, a synthesis method is introduced which uses the building blocks and the decomposition algorithm. Finally, a hybrid synthesis framework is suggested which uses the proposed cycle-based synthesis method in conjunction with one of the recent NCT-based synthesis approaches which is based on Reed-Muller (RM) spectra. The time complexity and the effectiveness of the proposed synthesis approach are analyzed in detail. Our analyses show that the proposed hybrid fra...

  14. Mapping site-based construction workers’ motivation: Expectancy theory approach

    Directory of Open Access Journals (Sweden)

    Parviz Ghoddousi

    2014-03-01

    Full Text Available The aim of this study is to apply a recently proposed model of motivation based on expectancy theory to site-based workers in the construction context and confirm the validity of this model for the construction industry. The study drew upon data from 194 site-based construction workers in Iran to test the proposed model of motivation. To this end, the structural equation modelling (SEM approach based on the confirmatory factor analysis (CFA technique was deployed. The study reveals that the proposed model of expectancy theory incorporating five indicators (i.e. intrinsic instrumentality, extrinsic instrumentality, intrinsic valence, extrinsic valence and expectancy is able to map the process of construction workers’ motivation. Nonetheless, the findings posit that intrinsic indicators could be more effective than extrinsic ones. This proffers the necessity of construction managers placing further focus on intrinsic motivators to motivate workers. 

  15. Model-based approach for elevator performance estimation

    Science.gov (United States)

    Esteban, E.; Salgado, O.; Iturrospe, A.; Isasa, I.

    2016-02-01

    In this paper, a dynamic model for an elevator installation is presented in the state space domain. The model comprises both the mechanical and the electrical subsystems, including the electrical machine and a closed-loop field oriented control. The proposed model is employed for monitoring the condition of the elevator installation. The adopted model-based approach for monitoring employs the Kalman filter as an observer. A Kalman observer estimates the elevator car acceleration, which determines the elevator ride quality, based solely on the machine control signature and the encoder signal. Finally, five elevator key performance indicators are calculated based on the estimated car acceleration. The proposed procedure is experimentally evaluated, by comparing the key performance indicators calculated based on the estimated car acceleration and the values obtained from actual acceleration measurements in a test bench. Finally, the proposed procedure is compared with the sliding mode observer.

  16. Mapping site-based construction workers’ motivation: Expectancy theory approach

    Directory of Open Access Journals (Sweden)

    Parviz Ghoddousi

    2014-03-01

    Full Text Available The aim of this study is to apply a recently proposed model of motivation based on expectancy theory to site-based workers in the construction context and confirm the validity of this model for the construction industry. The study drew upon data from 194 site-based construction workers in Iran to test the proposed model of motivation. To this end, the structural equation modelling (SEM approach based on the confirmatory factor analysis (CFA technique was deployed. The study reveals that the proposed model of expectancy theory incorporating five indicators (i.e. intrinsic instrumentality, extrinsic instrumentality, intrinsic valence, extrinsic valence and expectancy is able to map the process of construction workers’ motivation. Nonetheless, the findings posit that intrinsic indicators could be more effective than extrinsic ones. This proffers the necessity of construction managers placing further focus on intrinsic motivators to motivate workers.

  17. Tongue base schwannoma: report, review, and unique surgical approach.

    Science.gov (United States)

    Sawhney, Raja; Carron, Michael A; Mathog, Robert H

    2008-01-01

    Base of tongue schwannomas are exceedingly rare and therefore often are not immediately included in the differential diagnosis and treatment of oropharyngeal tumors. After a thorough review of the English literature, we found only 6 previously reported cases of tongue base schwannomas. We are contributing a report of a 37-year-old woman with progressive dysphagia, dysarthria, and large tongue base schwannoma. Diagnosis was confirmed by imaging studies and biopsy followed by surgical excision designed to preserve nerve function. A number of surgical approaches have been described for tongue base schwannomas. Each has its own degree of postoperative morbidity. The use of a unilateral transcervical incision with blunt dissection was simple and quickly accomplished with protection of nearby nerves. Histologic identification of Antoni A and B areas along with strong and diffuse staining with S-100 stain pathologically completed the diagnosis of schwannoma.

  18. Digital subtraction angiography in head and neck radiology

    Energy Technology Data Exchange (ETDEWEB)

    Carmody, R.F.; Seeger, J.F.; Smith, R.L.; Horsley, W.W.; Miller, R.W.

    1984-07-01

    Intravenous digital subtraction angiography (IVDSA) was used to evaluate 44 patients with suspected otolaryngologic abnormalities. Sixteen had IVDSA for pulsatile tinnitus or suspected glomus tumor of the petrous bone. Nine patients were evaluated because of pulsatile neck masses, and 12 others had suspected tumors of the neck, face, and paranasal sinuses. Seven had IVDSA following head and neck trauma. The technique of examination is described. The current indications of IVDSA in head and neck radiology are discussed. It is concluded that IVDSA is a suitable substitute for conventional angiography for many otolaryngologic conditions and, because of its safety, can be used more liberally.

  19. 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.

  20. Building enterprise reuse program--A model-based approach

    Institute of Scientific and Technical Information of China (English)

    梅宏; 杨芙清

    2002-01-01

    Reuse is viewed as a realistically effective approach to solving software crisis. For an organization that wants to build a reuse program, technical and non-technical issues must be considered in parallel. In this paper, a model-based approach to building systematic reuse program is presented. Component-based reuse is currently a dominant approach to software reuse. In this approach, building the right reusable component model is the first important step. In order to achieve systematic reuse, a set of component models should be built from different perspectives. Each of these models will give a specific view of the components so as to satisfy different needs of different persons involved in the enterprise reuse program. There already exist some component models for reuse from technical perspectives. But less attention is paid to the reusable components from a non-technical view, especially from the view of process and management. In our approach, a reusable component model--FLP model for reusable component--is introduced. This model describes components from three dimensions (Form, Level, and Presentation) and views components and their relationships from the perspective of process and management. It determines the sphere of reusable components, the time points of reusing components in the development process, and the needed means to present components in terms of the abstraction level, logic granularity and presentation media. Being the basis on which the management and technical decisions are made, our model will be used as the kernel model to initialize and normalize a systematic enterprise reuse program.

  1. Usefulness of CT angiography in diagnosing acute gastrointestinal bleeding:A meta-analysis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    AIM: To analyze the accuracy of computed tomography (CT) angiography in the diagnosis of acute gastrointestinal (GI) bleeding. METHODS: The MEDLINE, EMBASE, Cancerlit, Cochrane Library database, Sciencedirect, Springerlink and Scopus, from January 1995 to December 2009, were searched for studies evaluating the accuracy of CT angiography in diagnosing acute GI bleeding. Studies were included if the ycompared CT angiography to a reference standard of upper GI endoscopy, colonoscopy, angiography or surgery in ...

  2. Usefulness of helical CT angiography for diagnosis of anomalous origin of coronary artery. Comparison with coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Shinozaki, Hitoshi; Kondo, Takeshi; Ishikawa, Emiko [Fujita Health Univ., Toyoake, Aichi (Japan)] [and others

    1998-07-01

    Usefulness of helical CT angiography with reconstruction image of diastolic phase synchronized with electrocardiogram was compared with that of coronary angiography for diagnosis of anomalous origin of coronary artery. Patients were 2 males and 3 females, and average age was 66.4 year. Three cardiologists judged images and did not confirmed the origin and direction of coronary artery in 60% of cases. Helical CT was carried out with heartbeat <60/min by oral administration of propranolol (10-20 mg) one hour before the test. Half image was reconstructed by using data of diastolic phase which is 600 msec back from R-wave of an electrocardiogram. Multiplanar reconstruction (MPR) image and 3D image were provided. Two radiologists judged these images. A judgment was completed with 4 cases among 5 cases, and two judgments agreed well. For diagnosis of anomalous origin of coronary artery, helical CT had good accuracy and was more sensitive than coronary angiography. (K.H.)

  3. EFL READING INSTRUCTION: COMMUNICATIVE TASK-BASED APPROACH

    Directory of Open Access Journals (Sweden)

    Harison Mohd Sidek

    2012-07-01

    Full Text Available The purpose of this study was to examine the overarching framework of EFL (English as a Foreign Language reading instructional approach reflected in an EFL secondary school curriculum in Malaysia. Based on such analysis, a comparison was made if Communicative Task-Based Language is the overarching instructional approach for the Malaysian EFL secondary reading curriculum. This study used document reviews as the primary data collection. The coding of data analysis was based on the modifications of the components of Richards and Rodgers’s (2001 analysis of language teaching model. The curriculum was examined in terms of theories of SLA, theories of L2 reading as well as learner roles in relation to Communicative Task-Based Language Teaching (CTBLT characteristics. The findings of the study suggest that the majority of reading tasks in the selected EFL secondary reading curriculum is highly lacking CTBLT characteristics. The results of the study were discussed in relation to the current Malaysian EFL secondary curriculum framework and their implications on the EFL reading at the tertiary level.

  4. Query Based Approach Towards Spam Attacks Using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Gaurav Kumar Tak

    2010-10-01

    Full Text Available Currently, spam and scams are passive attack over the inbox which can initiated to steal some confidential information, to spread Worms, Viruses, Trojans, cookies and Sometimes they are used for phishing attacks. Spam mails are the major issue over mail boxes as well as over the internet. Spam mails can be the cause of phishing attack, hacking of banking accounts, attacks on confidential data. Spamming is growing at a rapid rate since sending a flood of mails is easy and very cheap. Spam mails disturb the mind-peace, waste time and consume various resources e.g., memory space and network bandwidth, so filtering of spam mails is a big issue in cyber security. This paper presents an novel approach of spam filtering which is based on some query generated approach on the knowledge base and also use some artificial neural network methods to detect the spam mails based on their behavior. analysis of the mail header, cross validation. Proposed methodology includes the 7 several steps which are well defined and achieve the higher accuracy. It works well with all kinds of spam mails (text based spam as well as image spam. Our tested data and experiments results shows promising results, and spam’s are detected out at least 98.17 % with 0.12% false positive.

  5. ARABIC PERSON NAMES RECOGNITION BY USING A RULE BASED APPROACH

    Directory of Open Access Journals (Sweden)

    Mohammed Aboaoga

    2013-01-01

    Full Text Available Name Entity Recognition is very important task in many natural language processing applications such as; Machine Translation, Question Answering, Information Extraction, Text Summarization, Semantic Applications and Word Sense Disambiguation. Rule-based approach is one of the techniques that are used for named entity recognition to identify the named entities such as a person names, location names and organization names. The recent rule-based methods have been applied to recognize the person names in political domain. They ignored the recognition of other named entity types such as locations and organizations. We have used the rule based approach for recognizing the named entity type (person names for Arabic. We have developed four rules for identifying the person names depending on the position of name. We have used an in-house Arabic corpus collected from newspaper achieves. The evaluation method that compares the results of the system with the manually annotated text has been applied in order to compute precision, recall and f-measure. In the experiment of this study, the average f-measure for recognizing person names are (92.66, 92.04 and 90.43% in sport, economic and politic domain respectively. The experimental results showed that our rule-based method achieved the highest f-measure values in sport domain comparing with political and economic domains.

  6. Syntactic and Sentence Feature Based Hybrid Approach for Text Summarization

    Directory of Open Access Journals (Sweden)

    D.Y. Sakhare

    2014-02-01

    Full Text Available Recently, there has been a significant research in automatic text summarization using feature-based techniques in which most of them utilized any one of the soft computing techniques. But, making use of syntactic structure of the sentences for text summarization has not widely applied due to its difficulty of handling it in summarization process. On the other hand, feature-based technique available in the literature showed efficient results in most of the techniques. So, combining syntactic structure into the feature-based techniques is surely smooth the summarization process in a way that the efficiency can be achieved. With the intention of combining two different techniques, we have presented an approach of text summarization that combines feature and syntactic structure of the sentences. Here, two neural networks are trained based on the feature score and the syntactic structure of sentences. Finally, the two neural networks are combined with weighted average to find the sentence score of the sentences. The experimentation is carried out using DUC 2002 dataset for various compression ratios. The results showed that the proposed approach achieved F-measure of 80% for the compression ratio 50 % that proved the better results compared with the existing techniques.

  7. Pedestrian detection from thermal images: A sparse representation based approach

    Science.gov (United States)

    Qi, Bin; John, Vijay; Liu, Zheng; Mita, Seiichi

    2016-05-01

    Pedestrian detection, a key technology in computer vision, plays a paramount role in the applications of advanced driver assistant systems (ADASs) and autonomous vehicles. The objective of pedestrian detection is to identify and locate people in a dynamic environment so that accidents can be avoided. With significant variations introduced by illumination, occlusion, articulated pose, and complex background, pedestrian detection is a challenging task for visual perception. Different from visible images, thermal images are captured and presented with intensity maps based objects' emissivity, and thus have an enhanced spectral range to make human beings perceptible from the cool background. In this study, a sparse representation based approach is proposed for pedestrian detection from thermal images. We first adopted the histogram of sparse code to represent image features and then detect pedestrian with the extracted features in an unimodal and a multimodal framework respectively. In the unimodal framework, two types of dictionaries, i.e. joint dictionary and individual dictionary, are built by learning from prepared training samples. In the multimodal framework, a weighted fusion scheme is proposed to further highlight the contributions from features with higher separability. To validate the proposed approach, experiments were conducted to compare with three widely used features: Haar wavelets (HWs), histogram of oriented gradients (HOG), and histogram of phase congruency (HPC) as well as two classification methods, i.e. AdaBoost and support vector machine (SVM). Experimental results on a publicly available data set demonstrate the superiority of the proposed approach.

  8. Matching sensors to missions using a knowledge-based approach

    Science.gov (United States)

    Preece, Alun; Gomez, Mario; de Mel, Geeth; Vasconcelos, Wamberto; Sleeman, Derek; Colley, Stuart; Pearson, Gavin; Pham, Tien; La Porta, Thomas

    2008-04-01

    Making decisions on how best to utilise limited intelligence, surveillance and reconnaisance (ISR) resources is a key issue in mission planning. This requires judgements about which kinds of available sensors are more or less appropriate for specific ISR tasks in a mission. A methodological approach to addressing this kind of decision problem in the military context is the Missions and Means Framework (MMF), which provides a structured way to analyse a mission in terms of tasks, and assess the effectiveness of various means for accomplishing those tasks. Moreover, the problem can be defined as knowledge-based matchmaking: matching the ISR requirements of tasks to the ISR-providing capabilities of available sensors. In this paper we show how the MMF can be represented formally as an ontology (that is, a specification of a conceptualisation); we also represent knowledge about ISR requirements and sensors, and then use automated reasoning to solve the matchmaking problem. We adopt the Semantic Web approach and the Web Ontology Language (OWL), allowing us to import elements of existing sensor knowledge bases. Our core ontologies use the description logic subset of OWL, providing efficient reasoning. We describe a prototype tool as a proof-of-concept for our approach. We discuss the various kinds of possible sensor-mission matches, both exact and inexact, and how the tool helps mission planners consider alternative choices of sensors.

  9. Java Applications Development Based on Component and Metacomponent Approach

    Directory of Open Access Journals (Sweden)

    Danijel Radošević

    2008-12-01

    Full Text Available Component based modeling offers new and improved approach to design, construction, implementation and evolution of software applications development. This kind of software applications development is usually represented by appropriate component model/diagram. UML, for example, offers component diagram for representation of this kind of model. On the other hand, metacomponents usage offers some new features which hardly could be achieved by using generic components. Firstly, implementation of program properties which are dispersed on different classes and other program units, i.e. aspects, is offered. This implies using automated process of assembling components and their interconnection for building applications, according to appropriate model offered in this paper, which also offers generic components usage. Benefits of this hybrid process are higher flexibility achieved by automated connection process, optimization through selective features inclusion and easier application maintenance and development. In this paper we offer an approach of application development based on hybrid component/metacomponent model. The component model is given by UML diagrams, while the metacomponent model is given by generator scripting model. We explain that hybrid approach on an example of Java Web application development.

  10. Combined use of 64-slice computed tomography angiography and gated myocardial perfusion SPECT for the detection of functionally relevant coronary artery stenoses. First results in a clinical setting concerning patients with stable angina

    Energy Technology Data Exchange (ETDEWEB)

    Hacker, M.; Hack, N.; Tiling, R. [Klinikum Grosshadern (Germany). Dept. of Nuclear Medicine; Jakobs, T.; Nikolaou, K.; Becker, C. [Klinikum Grosshadern (Germany). Dept. of Clinical Radiology; Ziegler, F. von; Knez, A. [Klinikum Grosshadern (Germany). Dept. of Cardiology; Koenig, A.; Klauss, V. [Medizinische Poliklinik-Innenstadt, Univ. of Munich (Germany). Dept. of Cardiology

    2007-07-01

    Aim: In patients with stable angina pectoris both morphological and functional information about the coronary artery tree should be present before revascularization therapy is performed. High accuracy was shown for spiral computed tomography (MDCT) angiography acquired with a 64-slice CT scanner compared to invasive coronary angiography (ICA) in detecting ''obstructive'' coronary artery disease (CAD). Gated myocardial SPECT (MPI) is an established method for the noninvasive assessment of functional significance of coronary stenoses. Aim of the study was to evaluate the combination of 64-slice CT angiography plus MPI in comparison to ICA plus MPI in the detection of hemodynamically relevant coronary artery stenoses in a clinical setting. Patients, methods: 30 patients (63 {+-} 10.8 years, 23 men) with stable angina (21 with suspected, 9 with known CAD) were investigated. MPI, 64-slice CT angiography and ICA were performed, reversible and fixed perfusion defects were allocated to determining lesions separately for MDCT angiography and ICA. The combination of MDCT angiography plus MPI was compared to the results of ICA plus MPI. Results: Sensitivity, specificity, negative and positive predictive value for the combination of MDCT angiography plus MPI was 85%, 97%, 98% and 79%, respectively, on a vessel-based and 93%, 87%, 93% and 88%, respectively, on a patient-based level. 19 coronary arteries with stenoses =50% in both ICA and MDCT angiography showed no ischemia in MPI. Conclusion: The combination of 64-slice CT angiography and gated myocardial SPECT enabled a comprehensive non-invasive view of the anatomical and functional status of the coronary artery tree. (orig.)

  11. Nanotechnology-Based Approaches for Guiding Neural Regeneration.

    Science.gov (United States)

    Shah, Shreyas; Solanki, Aniruddh; Lee, Ki-Bum

    2016-01-19

    The mammalian brain is a phenomenal piece of "organic machinery" that has fascinated scientists and clinicians for centuries. The intricate network of tens of billions of neurons dispersed in a mixture of chemical and biochemical constituents gives rise to thoughts, feelings, memories, and life as we know it. In turn, subtle imbalances or damage to this system can cause severe complications in physical, motor, psychological, and cognitive function. Moreover, the inevitable loss of nerve tissue caused by degenerative diseases and traumatic injuries is particularly devastating because of the limited regenerative capabilities of the central nervous system (i.e., the brain and spinal cord). Among current approaches, stem-cell-based regenerative medicine has shown the greatest promise toward repairing and regenerating destroyed neural tissue. However, establishing controlled and reliable methodologies to guide stem cell differentiation into specialized neural cells of interest (e.g., neurons and oligodendrocytes) has been a prevailing challenge in the field. In this Account, we summarize the nanotechnology-based approaches our group has recently developed to guide stem-cell-based neural regeneration. We focus on three overarching strategies that were adopted to selectively control this process. First, soluble microenvironmental factors play a critical role in directing the fate of stem cells. Multiple factors have been developed in the form of small-molecule drugs, biochemical analogues, and DNA/RNA-based vectors to direct neural differentiation. However, the delivery of these factors with high transfection efficiency and minimal cytotoxicity has been challenging, especially to sensitive cell lines such as stem cells. In our first approach, we designed nanoparticle-based systems for the efficient delivery of such soluble factors to control neural differentiation. Our nanoparticles, comprising either organic or inorganic elements, were biocompatible and offered

  12. Multimodality evaluation of dural arteriovenous fistula with CT angiography, MR with arterial spin labeling, and digital subtraction angiography: case report.

    Science.gov (United States)

    Alexander, Matthew; McTaggart, Ryan; Santarelli, Justin; Fischbein, Nancy; Marks, Michael; Zaharchuk, Greg; Do, Huy

    2014-01-01

    Dural arteriovenous fistulae (DAVF) are cerebrovascular lesions with pathologic shunting into the venous system from arterial feeders. Digital subtraction angiography (DSA) has long been considered the gold standard for diagnosis, but advances in noninvasive imaging techniques now play a role in the diagnosis of these complex lesions. Herein, we describe the case of a patient with right-side pulsatile tinnitus and DAVF diagnosed using computed tomography angiography, magnetic resonance with arterial spin labeling, and DSA. Implications for imaging analysis of DAVFs and further research are discussed.

  13. Rights-Based Approaches to Ensure Sustainable Nutrition Security.

    Science.gov (United States)

    Banerjee, Sweta

    2016-01-01

    In India, a rights-based approach has been used to address large-scale malnutrition, including both micro- and macro-level nutrition deficiencies. Stunting, which is an intergenerational chronic consequence of malnutrition, is especially widespread in India (38% among children under 5 years old). To tackle this problem, the government of India has designed interventions for the first 1,000 days, a critical period of the life cycle, through a number of community-based programs to fulfill the rights to food and life. However, the entitlements providing these rights have not yet produced the necessary changes in the malnutrition status of people, especially women and children. The government of India has already implemented laws and drafted a constitution that covers the needs of its citizens, but corruption, bureaucracy, lack of awareness of rights and entitlements and social discrimination limit people's access to basic rights and services. To address this crisis, Welthungerhilfe India, working in remote villages of the most backward states in India, has shifted from a welfare-based approach to a rights-based approach. The Fight Hunger First Initiative, started by Welthungerhilfe in 2011, is designed on the premise that in the long term, poor people can only leave poverty behind if adequate welfare systems are in place and if basic rights are fulfilled; these rights include access to proper education, sufficient access to adequate food and income, suitable health services and equal rights. Only then can the next generation of disadvantaged populations look forward to a new and better future and can growth benefit the entire society. The project, co-funded by the Federal Ministry for Economic Cooperation and Development, is a long-term multi-sectoral program that involves institution-building and empowerment.

  14. Iodixanol Has a Favourable Fibrinolytic Profile Compared to Iohexol in Cardiac Patients Undergoing Elective Angiography: A Double-Blind, Randomized, Parallel Group Study.

    Directory of Open Access Journals (Sweden)

    Andrew T Treweeke

    Full Text Available There is no consensus and a limited evidence base for choice of contrast agents (CA in angiography. This study evaluated the impact of iohexol and iodixanol CA on fibrinolytic factors (tissue plasminogen activator [t-PA] and plasminogen activator inhibitor-1 [PAI-1], as well as platelet-monocyte conjugates in cardiac patients undergoing elective angiography in a double-blind, randomised parallel group study.Patients (men, 50-70 years old; n = 12 were randomised to receive either iohexol (Omnipaque; n = 6 or iodixanol (Visipaque; n = 6 during elective angiography at Raigmore Hospital, Inverness, UK. Arterial and venous blood samples were drawn prior to CA delivery and following angiography. Assessment of platelet-monocyte conjugation, t-PA and PAI-1 antigen and activity was conducted in samples pre- and post-angiography.Plasma t-PA antigen was depressed equally in the study groups after angiography, but there was a greater reduction in PAI-1 antigen in the group receiving iodixanol. These findings corresponded to a substantial reduction in t-PA activity in patients receiving iohexol, with no change in those receiving iodixanol (P = 0.023 between the CA groups. Both CAs caused a reduction in platelet-monocyte conjugation, with no difference between the groups. No adverse events were reported during the trial.Avoiding reduced plasma t-PA activity might be an important consideration in choosing iodixanol over iohexol in patients at risk of thrombosis following angiography. The trial is registered on the ISRCTN register (ISRCTN51509735 and funded by the Coronary Thrombosis Trust and National Health Service (Highland R&D Endowments. The funders had no influence over study design or reporting.Controlled-Trials.com ISRCTN51509735.

  15. Scattered Data Processing Approach Based on Optical Facial Motion Capture

    Directory of Open Access Journals (Sweden)

    Qiang Zhang

    2013-01-01

    Full Text Available In recent years, animation reconstruction of facial expressions has become a popular research field in computer science and motion capture-based facial expression reconstruction is now emerging in this field. Based on the facial motion data obtained using a passive optical motion capture system, we propose a scattered data processing approach, which aims to solve the common problems of missing data and noise. To recover missing data, given the nonlinear relationships among neighbors with the current missing marker, we propose an improved version of a previous method, where we use the motion of three muscles rather than one to recover the missing data. To reduce the noise, we initially apply preprocessing to eliminate impulsive noise, before our proposed three-order quasi-uniform B-spline-based fitting method is used to reduce the remaining noise. Our experiments showed that the principles that underlie this method are simple and straightforward, and it delivered acceptable precision during reconstruction.

  16. APPROACH ON INTELLIGENT OPTIMIZATION DESIGN BASED ON COMPOUND KNOWLEDGE

    Institute of Scientific and Technical Information of China (English)

    Yao Jianchu; Zhou Ji; Yu Jun

    2003-01-01

    A concept of an intelligent optimal design approach is proposed, which is organized by a kind of compound knowledge model. The compound knowledge consists of modularized quantitative knowledge, inclusive experience knowledge and case-based sample knowledge. By using this compound knowledge model, the abundant quantity information of mathematical programming and the symbolic knowledge of artificial intelligence can be united together in this model. The intelligent optimal design model based on such a compound knowledge and the automatically generated decomposition principles based on it are also presented. Practically, it is applied to the production planning, process schedule and optimization of production process of a refining & chemical work and a great profit is achieved. Specially, the methods and principles are adaptable not only to continuous process industry, but also to discrete manufacturing one.

  17. Bridging Ayurveda with evidence-based scientific approaches in medicine.

    Science.gov (United States)

    Patwardhan, Bhushan

    2014-01-01

    This article reviews contemporary approaches for bridging Ayurveda with evidence-based medicine. In doing so, the author presents a pragmatic assessment of quality, methodology and extent of scientific research in Ayurvedic medicine. The article discusses the meaning of evidence and indicates the need to adopt epistemologically sensitive methods and rigorous experimentation using modern science. The author critically analyzes the status of Ayurvedic medicine based on personal observations, peer interactions and published research. This review article concludes that traditional knowledge systems like Ayurveda and modern scientific evidence-based medicine should be integrated. The author advocates that Ayurvedic researchers should develop strategic collaborations with innovative initiatives like 'Horizon 2020' involving predictive, preventive and personalized medicine (PPPM).

  18. An Efficient Fuzzy Clustering-Based Approach for Intrusion Detection

    CERN Document Server

    Nguyen, Huu Hoa; Darmont, Jérôme

    2011-01-01

    The need to increase accuracy in detecting sophisticated cyber attacks poses a great challenge not only to the research community but also to corporations. So far, many approaches have been proposed to cope with this threat. Among them, data mining has brought on remarkable contributions to the intrusion detection problem. However, the generalization ability of data mining-based methods remains limited, and hence detecting sophisticated attacks remains a tough task. In this thread, we present a novel method based on both clustering and classification for developing an efficient intrusion detection system (IDS). The key idea is to take useful information exploited from fuzzy clustering into account for the process of building an IDS. To this aim, we first present cornerstones to construct additional cluster features for a training set. Then, we come up with an algorithm to generate an IDS based on such cluster features and the original input features. Finally, we experimentally prove that our method outperform...

  19. Robust adaptive beamforming algorithm based on Bayesian approach

    Institute of Scientific and Technical Information of China (English)

    Xin SONG; Jinkuan WANG; Yinghua HAN; Han WANG

    2008-01-01

    The performance of adaptive array beamform-ing algorithms substantially degrades in practice because of a slight mismatch between actual and presumed array res-ponses to the desired signal. A novel robust adaptive beam-forming algorithm based on Bayesian approach is therefore proposed. The algorithm responds to the current envi-ronment by estimating the direction of arrival (DOA) of the actual signal from observations. Computational com-plexity of the proposed algorithm can thus be reduced com-pared with other algorithms since the recursive method is used to obtain inverse matrix. In addition, it has strong robustness to the uncertainty of actual signal DOA and makes the mean output array signal-to-interference-plus-noise ratio (SINR) consistently approach the optimum. Simulation results show that the proposed algorithm is bet-ter in performance than conventional adaptive beamform-ing algorithms.

  20. Evolutionary modeling-based approach for model errors correction

    Science.gov (United States)

    Wan, S. Q.; He, W. P.; Wang, L.; Jiang, W.; Zhang, W.

    2012-08-01

    The inverse problem of using the information of historical data to estimate model errors is one of the science frontier research topics. In this study, we investigate such a problem using the classic Lorenz (1963) equation as a prediction model and the Lorenz equation with a periodic evolutionary function as an accurate representation of reality to generate "observational data." On the basis of the intelligent features of evolutionary modeling (EM), including self-organization, self-adaptive and self-learning, the dynamic information contained in the historical data can be identified and extracted by computer automatically. Thereby, a new approach is proposed to estimate model errors based on EM in the present paper. Numerical tests demonstrate the ability of the new approach to correct model structural errors. In fact, it can actualize the combination of the statistics and dynamics to certain extent.

  1. Nucleic Acid-Based Therapy Approaches for Huntington's Disease

    Directory of Open Access Journals (Sweden)

    Tatyana Vagner

    2012-01-01

    Full Text Available Huntington's disease (HD is caused by a dominant mutation that results in an unstable expansion of a CAG repeat in the huntingtin gene leading to a toxic gain of function in huntingtin protein which causes massive neurodegeneration mainly in the striatum and clinical symptoms associated with the disease. Since the mutation has multiple effects in the cell and the precise mechanism of the disease remains to be elucidated, gene therapy approaches have been developed that intervene in different aspects of the condition. These approaches include increasing expression of growth factors, decreasing levels of mutant huntingtin, and restoring cell metabolism and transcriptional balance. The aim of this paper is to outline the nucleic acid-based therapeutic strategies that have been tested to date.

  2. A Competence-Based Approach to Sustainable Innovation Teaching

    DEFF Research Database (Denmark)

    McAloone, Timothy Charles

    2007-01-01

    the object of a research exercise, to affect and observe various approaches to the teaching of design. Particular attention will be paid in this case to competencies, both initiated in the teaching and the evaluated in the students’ interpretation of the theoretical contents. The lessons learned from...... on sustainable innovation. By focusing particularly on the Design & Innovation programme’s fifth semester, which is entitled Innovation for Sustainability, the efforts we have made to renew the educational approach and contents in our engineering teaching will be shown in this paper. This semester has been...... the first three years of this semester’s application and teaching to approximately 55 students per year are presented and discussed. After introducing the motivation and background for establishing the education programme, the consideration of competence-based education is described, in the context...

  3. Market-Based Approach to Mobile Surveillance Systems

    Directory of Open Access Journals (Sweden)

    Ahmed M. Elmogy

    2012-01-01

    Full Text Available The active surveillance of public and private sites is increasingly becoming a very important and critical issue. It is, therefore, imperative to develop mobile surveillance systems to protect these sites. Modern surveillance systems encompass spatially distributed mobile and static sensors in order to provide effective monitoring of persistent and transient objects and events in a given area of interest (AOI. The realization of the potential of mobile surveillance requires the solution of different challenging problems such as task allocation, mobile sensor deployment, multisensor management, cooperative object detection and tracking, decentralized data fusion, and interoperability and accessibility of system nodes. This paper proposes a market-based approach that can be used to handle different problems of mobile surveillance systems. Task allocation and cooperative target tracking are studied using the proposed approach as two challenging problems of mobile surveillance systems. These challenges are addressed individually and collectively.

  4. Classification approach based on association rules mining for unbalanced data

    CERN Document Server

    Ndour, Cheikh

    2012-01-01

    This paper deals with the supervised classification when the response variable is binary and its class distribution is unbalanced. In such situation, it is not possible to build a powerful classifier by using standard methods such as logistic regression, classification tree, discriminant analysis, etc. To overcome this short-coming of these methods that provide classifiers with low sensibility, we tackled the classification problem here through an approach based on the association rules learning because this approach has the advantage of allowing the identification of the patterns that are well correlated with the target class. Association rules learning is a well known method in the area of data-mining. It is used when dealing with large database for unsupervised discovery of local patterns that expresses hidden relationships between variables. In considering association rules from a supervised learning point of view, a relevant set of weak classifiers is obtained from which one derives a classification rule...

  5. An Agent Based approach to design Serious Game

    Directory of Open Access Journals (Sweden)

    Manuel Gentile

    2014-06-01

    Full Text Available Serious games are designed to train and educate learners, opening up new learning approaches like exploratory learning and situated cognition.  Despite growing interest in these games, their design is still an artisan process.On the basis of experiences in designing computer simulation, this paper proposes an agent-based approach to guide the design process of a serious game. The proposed methodology allows the designer to strike the right equilibrium between educational effectiveness and entertainment, realism and complexity.The design of the PNPVillage game is used as a case study. The PNPVillage game aims to introduce and foster an entrepreneurial mindset among young students. It was implemented within the framework of the European project “I  can… I cannot… I go!” Rev.2

  6. NEW APPROACH FOR IMAGE REPRESENTATION BASED ON GEOMETRIC STRUCTURAL CONTENTS

    Institute of Scientific and Technical Information of China (English)

    Jia Xiaomeng; Wang Guoyu

    2003-01-01

    This paper presents a novel approach for representation of image contents based on edge structural features. Edge detection is carried out for an image in the pre-processing stage.For feature representation, edge pixels are grouped into a set of segments through geometrical partitioning of the whole edge image. Then the invariant feature vector is computed for each edge-pixel segment. Thereby the image is represented with a set of spatially distributed feature vectors, each of which describes the local pattern of edge structures. Matching of two images can be achieved by the correspondence of two sets of feature vectors. Without the difficulty of image segmentation and object extraction due to the complexity of the real world images, the proposed approach provides a simple and flexible description for the image with complex scene, in terms of structural features of the image content. Experiments with real images illustrate the effectiveness of this new method.

  7. A Component Based Approach to Scientific Workflow Management

    CERN Document Server

    Le Goff, Jean-Marie; Baker, Nigel; Brooks, Peter; McClatchey, Richard

    2001-01-01

    CRISTAL is a distributed scientific workflow system used in the manufacturing and production phases of HEP experiment construction at CERN. The CRISTAL project has studied the use of a description driven approach, using meta- modelling techniques, to manage the evolving needs of a large physics community. Interest from such diverse communities as bio-informatics and manufacturing has motivated the CRISTAL team to re-engineer the system to customize functionality according to end user requirements but maximize software reuse in the process. The next generation CRISTAL vision is to build a generic component architecture from which a complete software product line can be generated according to the particular needs of the target enterprise. This paper discusses the issues of adopting a component product line based approach and our experiences of software reuse.

  8. A cloud-based approach to medical NLP.

    Science.gov (United States)

    Chard, Kyle; Russell, Michael; Lussier, Yves A; Mendonça, Eneida A; Silverstein, Jonathan C

    2011-01-01

    Natural Language Processing (NLP) enables access to deep content embedded in medical texts. To date, NLP has not fulfilled its promise of enabling robust clinical encoding, clinical use, quality improvement, and research. We submit that this is in part due to poor accessibility, scalability, and flexibility of NLP systems. We describe here an approach and system which leverages cloud-based approaches such as virtual machines and Representational State Transfer (REST) to extract, process, synthesize, mine, compare/contrast, explore, and manage medical text data in a flexibly secure and scalable architecture. Available architectures in which our Smntx (pronounced as semantics) system can be deployed include: virtual machines in a HIPAA-protected hospital environment, brought up to run analysis over bulk data and destroyed in a local cloud; a commercial cloud for a large complex multi-institutional trial; and within other architectures such as caGrid, i2b2, or NHIN.

  9. MR angiography with parallel acquisition for assessment of the visceral arteries: comparison with conventional MR angiography and 64-detector-row computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sutter, Reto [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Cantonal Hospital Winterthur, Department of Radiology, Winterthur (Switzerland); Heilmaier, Christina [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Lutz, Amelie M.; Willmann, Juergen K. [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Stanford University School of Medicine, Department of Radiology, Stanford, CA (United States); Weishaupt, Dominik [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Hospital Triemli, Department of Radiology, Zurich (Switzerland); Seifert, Burkhardt [University of Zurich, Biostatistics Unit, Institute of Social and Preventive Medicine, Zurich (Switzerland)

    2009-11-15

    The purpose of the study was to retrospectively compare three-dimensional gadolinium-enhanced magnetic resonance angiography (conventional MRA) with MRA accelerated by a parallel acquisition technique (fast MRA) for the assessment of visceral arteries, using 64-detector-row computed tomography angiography (MDCTA) as the reference standard. Eighteen patients underwent fast MRA (imaging time 17 s), conventional MRA (29 s) and MDCTA of the abdomen and pelvis. Two independent readers assessed subjective image quality and the presence of arterial stenosis. Data were analysed on per-patient and per-segment bases. Fast MRA yielded better subjective image quality in all segments compared with conventional MRA (P = 0.012 for reader 1, P = 0.055 for reader 2) because of fewer motion-induced artefacts. Sensitivity and specificity of fast MRA for the detection of arterial stenosis were 100% for both readers. Sensitivity of conventional MRA was 89% for both readers, and specificity was 100% (reader 1) and 99% (reader 2). Differences in sensitivity between the two types of MRA were not significant for either reader. Interobserver agreement for the detection of arterial stenosis was excellent for fast ({kappa} = 1.00) and good for conventional MRA ({kappa} = 0.76). Thus, subjective image quality of visceral arteries remains good on fast MRA compared with conventional MRA, and the two techniques do not differ substantially in the grading of arterial stenosis, despite the markedly reduced acquisition time of fast MRA. (orig.)

  10. Dual-energy direct bone removal CT angiography for evaluation of intracranial aneurysm or stenosis: comparison with conventional digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Yoshiyuki [National Cardiovascular Center, Department of Radiology, Osaka (Japan); St. Luke' s International Hospital, Department of Radiology, Tokyo (Japan); Uotani, Kensuke; Nakazawa, Tetsuro; Higashi, Masahiro; Yamada, Naoaki; Hori, Yoshiro; Kanzaki, Suzu; Fukuda, Tetsuya; Naito, Hiroaki [National Cardiovascular Center, Department of Radiology, Osaka (Japan); Itoh, Toshihide [Siemens Asahi Medical Technologies, Tokyo (Japan)

    2009-04-15

    Dual-energy CT can be applied for bone elimination in cerebral CT angiography (CTA). The aim of this study was to compare the results of dual-energy direct bone removal CTA (DE-BR-CTA) with those of digital subtraction angiography (DSA). Twelve patients with intracranial aneurysms and/or ICA stenosis underwent a dual-source CT in dual-energy mode. Post-processing software selectively removed bone structures using the two energy data sets. Three-dimensional images with and without bone removal were reviewed and compared to DSA. Dual-energy bone removal was successful in all patients. For 10 patients, bone removal was good and CTA maximum-intensity projection (MIP) images could be used for vessel evaluation. For two patients, bone removal was moderate with some bone remnants, but this did not inhibit the three-dimensional visualization. Three aneurysms adjacent to the skull base were only partially visible in conventional CTA but were fully visible in DE-BR-CTA. In five patients with ICA stenosis, DE-BR-CTA revealed the stenotic lesions on the MIP images. The correlation between DSA and DE-BR-CTA was good (R {sup 2}=0.822), but DE-BR-CTA led to an overestimation of stenosis. DE-BR-CTA was able to eliminate bone structure using only a single CT data acquisition and is useful to evaluate intracranial aneurysms and stenosis. (orig.)

  11. The Utility of Synthetic-based Approach of Writing among Iranian EFL Learners

    Directory of Open Access Journals (Sweden)

    Nasrin Derakhshandeh

    2014-05-01

    Full Text Available The present study intends to examine the utility of synthetic-based approach versus traditional approaches of writing among Iranian EFL learners. To achieve this end, ninety students at Upper-Intermediate level were randomly chosen from the English population of Kish and Gooyesh English Institutes. The students were divided into three groups. Group1 was asked to do a writing task based on product-based approach. A writing task based on process-oriented approach was administered to Group2; later on, Group 3 was invited to write a composition to assess their performance based on synthetic-based approach. The result of the t test and two-way ANOVA revealed that the students performed better in writing using synthetic approach rather than traditional approaches to writing. Keywords: EFL writing proficiency, Product-based approach, Process-based approach, Synthetic-based approach

  12. Online approach to feature interaction problems in middleware based system

    Institute of Scientific and Technical Information of China (English)

    HUANG Gang; LIU XuanZhe; MEI Hong

    2008-01-01

    As a popular infrastructure for distributed systems running on the Internet, middle-ware has to support much more diverse and complex interactions for coping with the drastically increasing demand on information technology and the extremely open and dynamic nature of the Internet. These supporting mechanisms facilitate the development, deployment, and integration of distributed systems, as well as increase the occasions for distributed systems to interact in an undesired way. The undesired interactions may cause serious problems, such as quality violation, function loss, and even system crash. In this paper, the problem is studied from the perspective of the feature interaction problem (FIP) in telecom, and an online ap-proach to the detection and solution on runtime systems is proposed. Based on a classification of middleware enabled interactions, the existence of FIP in middle-ware based systems is illustrated by four real cases and a conceptual comparison between middleware based systems and telecom systems. After that, runtime soft-ware architecture is employed to facilitate the online detection and solution of FIP. The approach is demonstrated on J2EE (Java 2 Platform Enterprise Edition) and applied to detect and resolve all of the four real cases.

  13. Big Data Analytics in Immunology: A Knowledge-Based Approach

    Directory of Open Access Journals (Sweden)

    Guang Lan Zhang

    2014-01-01

    Full Text Available With the vast amount of immunological data available, immunology research is entering the big data era. These data vary in granularity, quality, and complexity and are stored in various formats, including publications, technical reports, and databases. The challenge is to make the transition from data to actionable knowledge and wisdom and bridge the knowledge gap and application gap. We report a knowledge-based approach based on a framework called KB-builder that facilitates data mining by enabling fast development and deployment of web-accessible immunological data knowledge warehouses. Immunological knowledge discovery relies heavily on both the availability of accurate, up-to-date, and well-organized data and the proper analytics tools. We propose the use of knowledge-based approaches by developing knowledgebases combining well-annotated data with specialized analytical tools and integrating them into analytical workflow. A set of well-defined workflow types with rich summarization and visualization capacity facilitates the transformation from data to critical information and knowledge. By using KB-builder, we enabled streamlining of normally time-consuming processes of database development. The knowledgebases built using KB-builder will speed up rational vaccine design by providing accurate and well-annotated data coupled with tailored computational analysis tools and workflow.

  14. A practical approach to object based requirements analysis

    Science.gov (United States)

    Drew, Daniel W.; Bishop, Michael

    1988-01-01

    Presented here is an approach developed at the Unisys Houston Operation Division, which supports the early identification of objects. This domain oriented analysis and development concept is based on entity relationship modeling and object data flow diagrams. These modeling techniques, based on the GOOD methodology developed at the Goddard Space Flight Center, support the translation of requirements into objects which represent the real-world problem domain. The goal is to establish a solid foundation of understanding before design begins, thereby giving greater assurance that the system will do what is desired by the customer. The transition from requirements to object oriented design is also promoted by having requirements described in terms of objects. Presented is a five step process by which objects are identified from the requirements to create a problem definition model. This process involves establishing a base line requirements list from which an object data flow diagram can be created. Entity-relationship modeling is used to facilitate the identification of objects from the requirements. An example is given of how semantic modeling may be used to improve the entity-relationship model and a brief discussion on how this approach might be used in a large scale development effort.

  15. COPULA BASED VaR APPROACH FOR EUROPEAN STOCKS PORTFOLIO

    Directory of Open Access Journals (Sweden)

    Mária Bohdalová

    2013-06-01

    Full Text Available The paper gives stochastic assessments of the financial crisis and discusses the Value at Risk European stocks from the point of view of copula based approach. Copula techniques can be based on the connection between rank correlation and certain one–parameter bivariate copulas. This relation allows easy calibration of the parameters. We use more general numerical calibration techniques that are based on maximum likelihood estimation (MLE. Using this approach we want to estimate VaR of the EU stocks portfolio using Monte Carlo simulation. The focus will be on modelling the interdependence between two risk factor returns. We suppose that the risk factor returns have some assumed marginal distributions, which need not be identical, and their dependency is modelled with copulas. We find that standard parametric copula functions (such as Gaussian are not able to provide a good fit to the data. This is especially true when one or more of the marginal distributions has fat tails. We overcome this problem by fitting a t–copula with different marginal which can approximate any possible shape for the joint density.

  16. A web-based approach to data imputation

    KAUST Repository

    Li, Zhixu

    2013-10-24

    In this paper, we present WebPut, a prototype system that adopts a novel web-based approach to the data imputation problem. Towards this, Webput utilizes the available information in an incomplete database in conjunction with the data consistency principle. Moreover, WebPut extends effective Information Extraction (IE) methods for the purpose of formulating web search queries that are capable of effectively retrieving missing values with high accuracy. WebPut employs a confidence-based scheme that efficiently leverages our suite of data imputation queries to automatically select the most effective imputation query for each missing value. A greedy iterative algorithm is proposed to schedule the imputation order of the different missing values in a database, and in turn the issuing of their corresponding imputation queries, for improving the accuracy and efficiency of WebPut. Moreover, several optimization techniques are also proposed to reduce the cost of estimating the confidence of imputation queries at both the tuple-level and the database-level. Experiments based on several real-world data collections demonstrate not only the effectiveness of WebPut compared to existing approaches, but also the efficiency of our proposed algorithms and optimization techniques. © 2013 Springer Science+Business Media New York.

  17. Big data analytics in immunology: a knowledge-based approach.

    Science.gov (United States)

    Zhang, Guang Lan; Sun, Jing; Chitkushev, Lou; Brusic, Vladimir

    2014-01-01

    With the vast amount of immunological data available, immunology research is entering the big data era. These data vary in granularity, quality, and complexity and are stored in various formats, including publications, technical reports, and databases. The challenge is to make the transition from data to actionable knowledge and wisdom and bridge the knowledge gap and application gap. We report a knowledge-based approach based on a framework called KB-builder that facilitates data mining by enabling fast development and deployment of web-accessible immunological data knowledge warehouses. Immunological knowledge discovery relies heavily on both the availability of accurate, up-to-date, and well-organized data and the proper analytics tools. We propose the use of knowledge-based approaches by developing knowledgebases combining well-annotated data with specialized analytical tools and integrating them into analytical workflow. A set of well-defined workflow types with rich summarization and visualization capacity facilitates the transformation from data to critical information and knowledge. By using KB-builder, we enabled streamlining of normally time-consuming processes of database development. The knowledgebases built using KB-builder will speed up rational vaccine design by providing accurate and well-annotated data coupled with tailored computational analysis tools and workflow.

  18. Lessons Learned From Community-Based Approaches to Sodium Reduction

    Science.gov (United States)

    Kane, Heather; Strazza, Karen; Losby PhD, Jan L.; Lane, Rashon; Mugavero, Kristy; Anater, Andrea S.; Frost, Corey; Margolis, Marjorie; Hersey, James

    2017-01-01

    Purpose This article describes lessons from a Centers for Disease Control and Prevention initiative encompassing sodium reduction interventions in six communities. Design A multiple case study design was used. Setting This evaluation examined data from programs implemented in six communities located in New York (Broome County, Schenectady County, and New York City); California (Los Angeles County and Shasta County); and Kansas (Shawnee County). Subjects Participants (n = 80) included program staff, program directors, state-level staff, and partners. Measures Measures for this evaluation included challenges, facilitators, and lessons learned from implementing sodium reduction strategies. Analysis The project team conducted a document review of program materials and semi structured interviews 12 to 14 months after implementation. The team coded and analyzed data deductively and inductively. Results Five lessons for implementing community-based sodium reduction approaches emerged: (1) build relationships with partners to understand their concerns, (2) involve individuals knowledgeable about specific venues early, (3) incorporate sodium reduction efforts and messaging into broader nutrition efforts, (4) design the program to reduce sodium gradually to take into account consumer preferences and taste transitions, and (5) identify ways to address the cost of lower-sodium products. Conclusion The experiences of the six communities may assist practitioners in planning community-based sodium reduction interventions. Addressing sodium reduction using a community-based approach can foster meaningful change in dietary sodium consumption. PMID:24575726

  19. Slovenian experience from diagnostic angiography to interventional radiology

    Directory of Open Access Journals (Sweden)

    Pavcnik Dusan

    2014-12-01

    Full Text Available Background. The purpose of writing this article is to document the important events and people in the first 50 years of diagnostic angiography and interventional radiology in Slovenia. During this period not only did the name of the institutions and departments change, but also its governance.

  20. Value of abdominal angiography in Turner's syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, A.; Castaneda-Zuniga, W.R.; Velasquez, G.; Zollikofer, C.; Amplatz, K.

    1981-01-01

    In patients with Turner's syndrome, there is a relatively high incidence of gastrointestinal bleeding due to telangiectasias of the intestine. Despite the importance of preoperative diagnosis of the lesion in planning surgical treatment. The related angiographic findings have never been reported. We have studied one patient in whom the diagnosis was established by preoperative angiography.

  1. [A man with vision problems after coronary angiography].

    Science.gov (United States)

    Salomé, Mariet E; Jansen, Ben P W

    2015-01-01

    A 71-year-old man underwent a coronary angiography (CAG). Afterwards he experienced vision loss. Neurologic examination revealed bilateral cortical blindness. A cerebral CT-scan showed occipital hyperdensity, due to contrast accumulation and oedema. There was complete recovery of vision within 2 days. Transient cortical blindness after CAG is a rare complication of iodinated contrast agents.

  2. Neurologic complications of cerebral angiography in childhood moyamoya syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, R.L.; Chavali, R.V.; Robson, C.D.; Barnes, P.D.; Burrows, P.E. [Department of Radiology, Children`s Hospital Medical Center, Boston, MA (United States); Eldredge, E.A. [Department of Anesthesia, Children`s Hospital Medical Center and Harvard Medical School, Boston, MA (United States); Scott, R.M. [Department of Neurosurgery, Children`s Hospital Medical Center and Harvard Medical School, Boston, MA (United States)

    1998-11-01

    Purpose. To determine the incidence of neurologic complications of cerebral angiography in children with moyamoya syndrome (MMS) as compared to children without MMS. Materials and methods. One-hundred-ninety consecutive cerebral angiograms obtained in 152 children were evaluated. Sixty of these angiograms were obtained in 40 children with MMS. Patients underwent neurologic evaluation prior to and after the procedure. For this study, a neurologic complication was defined as any new focal neurologic deficit or alteration in mental status occurring during the procedure or within the ensuing 24 hours. Results. There were 2 neurologic complications within 24 hours of angiography, one in the MMS group and one in the non-MMS group. One patient with MMS became mute following angiography. The symptom resolved within 12 hours. One patient without MMS being examined postoperatively for residual arteriovenous malformation developed intracranial hemorrhage requiring reexploration 12 hours after the angiogram. Using a two-tail Fisher`s exact test, there was no significant statistical difference in the ischemic (P = 0.3) or hemorrhagic (P = 1.0) complication rates between the group of patients with MMS and the non-MMS groups. Conclusion. The risk of a neurologic complication from cerebral angiography in children with MMS is low and not statistically different from the risk in children with other cerebrovascular disorders. (orig.) With 8 tabs., 37 refs.

  3. Non-enhanced MR angiography of renal arteries - Comparison with contrast-enhanced MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Angeretti, M. G.; Lumia, D.; Cani, A.; Barresi, M.; Cardim, L Nocchi; Piacentino, F.; Genovese, E. A.; Fugazzola, C. [Dept. of Radiology, Insubria Univ., Ospedale di Circolo e Fondazione Macchi, Varese (Italy)], e-mail: laranocchi@gmail.com; Maresca, A. M. [Dept. of Internal Medicine, Insubria Univ., Ospedale di Circolo e Fondazione Macchi, Varese (Italy); Novario, R. [Dept. of Medical Physics, Insubria Univ., Ospedale di Circolo e Fondazione Macchi, Varese (Italy)

    2013-09-15

    Background: The main causes of renal artery stenosis (RAS) are atherosclerosis and fibromuscular dysplasia. Despite contrast-enhanced magnetic resonance angiography (CE-MRA) being a safe and reliable method for diagnosis of RAS especially in young individuals, recently it has been possible to adopt innovative technologies that do not require paramagnetic contrast agents. Purpose: To assess the accuracy of steady-state free-precession (SSFP) non-contrast-enhanced magnetic resonance angiography (NC-MRA) by using a 1.5 T MR scanner for the detection of renal artery stenosis, in comparison with breath-hold CE-MRA as the reference standard. Material and Methods: Sixty-three patients (33 men, 30 women) with suspected renovascular hypertension (RVHT) were examined by a 1.5T MR scanner; NC-MRA with an electrocardiography (ECG)-gated SSFP sequence was performed in 58.7% (37/63) of patients; in 41.3% (26/63) of patients a respiratory trigger was used in addition to cardiac gating. CE-MRA, with a three-dimensional gradient echo (3D-GRE) T1-weighted sequence, was performed in all patients within the same session. Maximum intensity projection (MIP) image quality, number of renal arteries, and the presence of stenosis were assessed by two observers (independently for NC-MRA and together for CE-MRA). The agreement between NC-MRA and CE-MRA as well as the inter-observer reproducibility were calculated with Bland-Altman plots. Results: MIP image quality was considered better for NC-MRA. NC-MRA identified 143 of 144 (99.3%) arteries detected by CE-MRA (an accessory artery was not identified). Fourteen stenoses were detected by CE-MRA (11 atherosclerotic, 3 dysplastic) with four of 14 (28.5%) significant stenosis. Bland-Altman plot demonstrated an excellent concordance between NC-MRA and CE-MRA; particularly, the reader A evaluated correctly all investigated arteries, while over-estimation of two stenoses occurred for reader B. Regarding NC-MRA, inter-observer agreement was excellent

  4. Spatial interpolation approach based on IDW with anisotropic spatial structures

    Science.gov (United States)

    Li, Jia; Duan, Ping; Sheng, Yehua; Lv, Haiyang

    2015-12-01

    In many interpolation methods, with its simple interpolation principle, Inverse distance weighted (IDW) interpolation is one of the most common interpolation method. There are anisotropic spatial structures with actual geographical spatial phenomenon. When the IDW interpolation is used, anisotropic spatial structures should be considered. Geostatistical theory has a characteristics of exploring anisotropic spatial structures. In this paper, spatial interpolation approach based on IDW with anisotropic spatial structures is proposed. The DEM data is tested in this paper to prove reliability of the IDW interpolation considering anisotropic spatial structures. Experimental results show that IDW interpolation considering anisotropic spatial structures can improve interpolation precision when sampling data has anisotropic spatial structures feature.

  5. A Multiple Model Approach to Modeling Based on LPF Algorithm

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Input-output data fitting methods are often used for unknown-structure nonlinear system modeling. Based on model-on-demand tactics, a multiple model approach to modeling for nonlinear systems is presented. The basic idea is to find out, from vast historical system input-output data sets, some data sets matching with the current working point, then to develop a local model using Local Polynomial Fitting (LPF) algorithm. With the change of working points, multiple local models are built, which realize the exact modeling for the global system. By comparing to other methods, the simulation results show good performance for its simple, effective and reliable estimation.``

  6. Conceptual modelling approach of mechanical products based on functional surface

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A modelling framework based on functional surface is presented to support conceptual design of mechanical products. The framework organizes product information in an abstract and multilevel manner. It consists of two mapping processes: function decomposition process and form reconstitution process. The steady mapping relationship from function to form (function-functional surface-form) is realized by taking functional surface as the middle layer. It farthest reduces the possibilities of combinatorial explosion that can occur during function decomposition and form reconstitution. Finally, CAD tools are developed and an auto-bender machine is applied to demonstrate the proposed approach.

  7. Infections on Temporal Networks—A Matrix-Based Approach

    Science.gov (United States)

    Koher, Andreas; Lentz, Hartmut H. K.; Hövel, Philipp; Sokolov, Igor M.

    2016-01-01

    We extend the concept of accessibility in temporal networks to model infections with a finite infectious period such as the susceptible-infected-recovered (SIR) model. This approach is entirely based on elementary matrix operations and unifies the disease and network dynamics within one algebraic framework. We demonstrate the potential of this formalism for three examples of networks with high temporal resolution: networks of social contacts, sexual contacts, and livestock-trade. Our investigations provide a new methodological framework that can be used, for instance, to estimate the epidemic threshold, a quantity that determines disease parameters, for which a large-scale outbreak can be expected. PMID:27035128

  8. A Clock Fingerprints-Based Approach for Wireless Transmitter Identification

    Science.gov (United States)

    Zhao, Caidan; Xie, Liang; Huang, Lianfen; Yao, Yan

    Cognitive radio (CR) was proposed as one of the promising solutions for low spectrum utilization. However, security problems such as the primary user emulation (PUE) attack severely limit its applications. In this paper, we propose a clock fingerprints-based authentication approach to prevent PUE attacks in CR networks with the help of curve fitting and classifier. An experimental setup was constructed using the WLAN cards and software radio devices, and the corresponding results show that satisfied identification can be achieved for wireless transmitters.

  9. Reconfigurable diplexer based on switched delay line approach

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Acar, Öncel; Ruaro, Andrea;

    2013-01-01

    In this work, a concept for the realization of a reconfigurable microwave multiplexer based on a switched delay-line topology is presented. The multiplexing concept is studied by considering a diplexer example. The topology provides two times reduction in the number of filters in comparison...... to the conventional directional filter approach. The switched delay-line topology enables the lossy and nonlinear switching elements to be used as a part of the coupling elements rather than within the resonators. Therefore, the diplexer potentially allows for a low insertion loss and high linearity. In addition...

  10. A CONTENT ANALYSIS ON PROBLEM-BASED LEARNING APPROACH

    OpenAIRE

    BİBER, Mahir; Esen ERSOY; KÖSE BİBER, Sezer

    2014-01-01

    Problem Based Learning is one of the learning models that contain the general principles of active learning and students can use scientific process skills. Within this research it was aimed to investigate in detail the postgraduate thesis held in Turkey about PBL approach. The content analysis method was used in the research. The study sample was consisted of a total of 64 masters and PhD thesis made between the years 2012-2013 and reached over the web. A “Content Analysis Template” prepared ...

  11. A CONTENT ANALYSIS ON PROBLEM-BASED LEARNING APPROACH

    OpenAIRE

    BİBER, Mahir; Esen ERSOY; KÖSE BİBER, Sezer

    2015-01-01

    Problem Based Learning is one of the learning models that contain the general principles of active learning and students can use scientific process skills. Within this research it was aimed to investigate in detail the postgraduate thesis held in Turkey about PBL approach. The content analysis method was used in the research. The study sample was consisted of a total of 64 masters and PhD thesis made between the years 2012-2013 and reached over the web. A “Content Analysis Template” prepared ...

  12. A newly developed technique involving the optimization of flow velocity compensation for lower extremity CT angiography

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; XU Dong; LI KunCheng; JIN ErHu; BARNES Bret

    2013-01-01

    Advanced computed tomography (CT) technology has allowed for faster and more robust imaging.However,it has been a technical challenge to correctly synchronize CT acquisition with adequate and uniform arterial enhancement in the entire peripheral arterial tree.In this summary,we introduce a method of injection/acquisition optimization strategy based on a velocity-compensated CT angiography technique for the peripheral artery system,which is currently used in the United States.We believe that this imaging technique will provide additional information for our daily CT services in China.

  13. Dose reduction during CT coronary angiography; La reduction de dose en coroscanographie

    Energy Technology Data Exchange (ETDEWEB)

    Willoteaux, S.; Sibileau, E.; Caroff, J.; Nedelcu, C.; Thouveny, F. [Service de Radiologie, Hopital Larrey, CHU d' Angers, 49 - Angers (France); Abi Kalil, W.; Delepine, S. [Service de Cardiologie, Hopital Larrey, CHU d' Angers, 49 - Angers (France)

    2010-11-15

    Dose delivery during CT coronary angiography with retrospective ECG gating is high especially due to the important slice overlapping. Optimization of the acquisition parameters is necessary to reduce patient exposure. First, the height of the scan field should be limited to the heart. Both kV and mA should be adjusted based on patient morphology. ECG gated exposure modulation with mA reduction during systole, a technique most applicable for patients with slow and regular heart rate, can result in a dose reduction up to 50%. The use of prospective ECG gating can also reduce patient dose. This technique also requires patients with slow and regular heart rate. (authors)

  14. Quantification of choroidal neovascularization vessel length using optical coherence tomography angiography

    Science.gov (United States)

    Gao, Simon S.; Liu, Li; Bailey, Steven T.; Flaxel, Christina J.; Huang, David; Li, Dengwang; Jia, Yali

    2016-07-01

    Quantification of choroidal neovascularization (CNV) as visualized by optical coherence tomography angiography (OCTA) may have importance clinically when diagnosing or tracking disease. Here, we present an automated algorithm to quantify the vessel skeleton of CNV as vessel length. Initial segmentation of the CNV on en face angiograms was achieved using saliency-based detection and thresholding. A level set method was then used to refine vessel edges. Finally, a skeleton algorithm was applied to identify vessel centerlines. The algorithm was tested on nine OCTA scans from participants with CNV and comparisons of the algorithm's output to manual delineation showed good agreement.

  15. Influence of Adaptive Statistical Iterative Reconstruction on coronary plaque analysis in coronary computed tomography angiography

    DEFF Research Database (Denmark)

    Precht, Helle; Kitslaar, Pieter H; Broersen, Alexander

    2016-01-01

    PURPOSE: The purpose of this study was to study the effect of iterative reconstruction (IR) software on quantitative plaque measurements in coronary computed tomography angiography (CCTA). METHODS: Thirty patients with a three clinical risk factors for coronary artery disease (CAD) had one CCTA...... performed. Images were reconstructed using FBP, 30% and 60% adaptive statistical IR (ASIR). Coronary plaque analysis was performed as per patient and per vessel (LM, LAD, CX and RCA) measurements. Lumen and vessel volumes and plaque burden measurements were based on automatic detected contours in each...

  16. Acute versus subacute angiography in patients with non-ST-elevation myocardial infarction - the NONSTEMI trial phase I

    DEFF Research Database (Denmark)

    Stengaard, Carsten; Sørensen, Jacob T; Rasmussen, Martin B;

    2016-01-01

    patients to either acute or subacute CAG (i.e. care troponin-T measurement ensured that 148 (59%) patients were identified already in the ambulance, whereas the remaining 102 (41%) patients were identified immediately after...... randomized to subacute CAG it was two days. Time from randomization to initial revascularization was 1.3 h versus 2.4 days, and the median hospital stay was 4.0 days versus 4.5 days. Among patients randomized to subacute CAG, 17% crossed over to acute CAG and 5% developed STEMI before catheterization......BACKGROUND: The 2015 European Society of Cardiology non-ST-elevation myocardial infarction (NSTEMI) guidelines recommend angiography within 24 h in high-risk patients with NSTEMI. An organized STEMI-like approach with pre-hospital or immediate in-hospital triage for acute coronary angiography (CAG...

  17. Angiographic leakage of polypoidal choroidal vasculopathy on indocyanine angiography

    Institute of Scientific and Technical Information of China (English)

    ZUO Cheng-guo; WEN Feng; HUANG Shi-zhou; LUO Guang-wei; YAN Hong; WU Wei-ju; WU De-zheng

    2010-01-01

    Background There is no detailed report about the angiographic leakage of polypoidal choroidal vasculopathy (PCV)lesions on indocyanine green (ICG) angiography. This study aimed to investigate the angiographic leakage of polypoidal lesions in PCV on ICG angiography.Methods One hundred and forty-four eyes of 137 patients diagnosed as PCV were prospectively observed. Fundus examination, fluorescein angiography, and ICG angiography were performed. Leakage of polypoidal lesions and clinical features were recorded according to the angiograms.Results In all 144 eyes, 110 eyes showed angiographic leakage (leakage group) on ICG angiography and three subtypes of leakage group were noted, which were polypoidal dilations leakage (47 eyes, 42.7%), branching vascular networks leakage (14 eyes, 12.7%) and leakage of both (49 eyes, 44.5%). The other 34 eyes showed regression of polypoidal lesions (regression group). In leakage group, the rates of pigment epithelial detachment (PED), best corrected visual acuity (BCVA) <0.1 and old subretinal hemorrhages were 56.4% (62 eyes), 19.1% (21 eyes), and 4.6% (5 eyes)respectively, compared with 8.8% (3 eyes), 50% (17 eyes) and 38.2% (13 eyes) of regression group (P <0.001). The history of regression group was significantly longer (P <0.001).Conclusions Angiographic leakage and regression can be observed in PCV lesions. Leakage of both polypoidal dilations and branching vascular networks is the most common subtype in leakage group. PCV in leakage group is more likely to be related to PED, better BCVA and shorter history, while PCV regression group tends to relevant to old subretinal hemorrhage, worse BCVA and longer history. This may reflect that the former is active or in the early course while the later is resting or in the late phase of PCV.

  18. Case Report of Bullous Pemphigoid following Fundus Fluorescein Angiography

    Directory of Open Access Journals (Sweden)

    Goktug Demirci

    2010-05-01

    Full Text Available Purpose: To report a first case of bullous pemphigoid (BP following intravenous fluorescein for fundus angiography. Clinical Features: A 70-year-old male patient was admitted to the intensive care unit with BP and sepsis. He reported a history of fundus fluorescein angiography with a pre-diagnosis of senile macular degeneration 2 months prior to presentation. At that time, fluorescein extravasated at the antecubital region. Following the procedure, pruritus and erythema began at the wrists bilaterally, and quickly spread to the entire body. The patient also reported a history of allergy to human albumin solution (Plamasteril®; Abbott 15 years before, during bypass surgery. On dermatologic examination, erythematous patches were present on the scalp, chest and anogenital region. Vesicles and bullous lesions were present on upper and lower extremities. On day 2 of hospitalization, tense bullae appeared on the upper and lower extremities. The patient was treated with oral methylprednisolone 48 mg (Prednol®; Mustafa Nevzat, topical clobetasol dipropionate 0.05% cream (Dermovate®; Glaxo SmithKline, and topical 4% urea lotion (Excipial Lipo®; Orva for presumptive bullous pemphigoid. Skin punch biopsy provided tissue for histopathology, direct immunofluorescence examination, and salt extraction, which were all consistent with BP. After 1 month, the patient was transferred to the intensive care unit with sepsis secondary to urinary tract infection; he died 2 weeks later from sepsis and cardiac failure. Conclusions: To our knowledge, this is the first reported case of BP following fundus fluorescein angiography in a patient with known human albumin solution allergy. Consideration should be made to avoid fluorescein angiography, change administration route, or premedicate with antihistamines in patients with known human albumin solution allergy. The association between fundus fluorescein angiography and BP should be further investigated.

  19. An Approach to Model Based Testing of Multiagent Systems

    Directory of Open Access Journals (Sweden)

    Shafiq Ur Rehman

    2015-01-01

    Full Text Available Autonomous agents perform on behalf of the user to achieve defined goals or objectives. They are situated in dynamic environment and are able to operate autonomously to achieve their goals. In a multiagent system, agents cooperate with each other to achieve a common goal. Testing of multiagent systems is a challenging task due to the autonomous and proactive behavior of agents. However, testing is required to build confidence into the working of a multiagent system. Prometheus methodology is a commonly used approach to design multiagents systems. Systematic and thorough testing of each interaction is necessary. This paper proposes a novel approach to testing of multiagent systems based on Prometheus design artifacts. In the proposed approach, different interactions between the agent and actors are considered to test the multiagent system. These interactions include percepts and actions along with messages between the agents which can be modeled in a protocol diagram. The protocol diagram is converted into a protocol graph, on which different coverage criteria are applied to generate test paths that cover interactions between the agents. A prototype tool has been developed to generate test paths from protocol graph according to the specified coverage criterion.

  20. Knowledge-based approaches for river basin management

    Directory of Open Access Journals (Sweden)

    P. Mikulecký

    2007-06-01

    Full Text Available Rare attempts to use knowledge technologies and other relevant approaches are found in the river basin management. Some applications of expert systems as well as utilization of soft computing techniques (as neural networks or genetic algorithms are known in an experimental level. Knowledge management approaches still have not been used at all. In this paper we discuss knowledge-based approaches in the river basin management as a difficult yet important direction which could be proven to be helpful. We summarize the research done in the scope of the AQUIN project, one of first Czech knowledge management projects in the river basin management. The project was initiated by the water management company in Pilsen, where dispatchers make decisions about manipulations on the reservoir Nýrsko, the strategic source of drinking water for inhabitants of Pilsen. The project aim was to support dispatchers' decision making under a high degree of uncertainty or data shortage. The research is continued in the scope of a new project AQUINpro, planned for the period of 2006 to 2008.

  1. A Redundancy Based Approach for Wireless Sensor Networks Distributed Reconfiguration

    Directory of Open Access Journals (Sweden)

    Bechar Rachid

    2016-05-01

    Full Text Available In this paper, we are interested in the fault-tolerant and lifetime optimisation approaches in wireless sensor networks (WSN. We propose a WSN monitoring approach using distributed reconfiguration which is based on the concept of redundancy. This allows the sensor nodes to be organized in groups where each one will have a quite precise role. It also makes it possible to manage redundancy which will consist in leaving active only some nodes. The other redundant member nodes go into sleep mode and will be awaked using an operation of reconfiguration in case of fault. A node can be also a data source measurement, called simple node or a gateway node that may be used in several groups at the same time, and whose main role is to provide the communication function, each group is managed by a coordinator. The evaluation results of this approach showed that this distributed structure is suitable to ensure simultaneously the fault-tolerance property and to improve the performance and the network lifetime.

  2. Normal mode-based approaches in receptor ensemble docking.

    Science.gov (United States)

    Cavasotto, Claudio N

    2012-01-01

    Explicitly accounting for target flexibility in docking still constitutes a difficult challenge due to the high dimensionality of the conformational space to be sampled. This especially applies to the high-throughput scenario, where the screening of hundreds of thousands compounds takes place. The use of multiple receptor conformations (MRCs) to perform ensemble docking in a sequential fashion is a simple but powerful approach that allows to incorporate binding site structural diversity in the docking process. Whenever enough experimental structures to build a diverse ensemble are not available, normal mode analysis provides an appealing and efficient approach to in silico generate MRCs by distortion along few low-frequency modes that represent collective mid- and large-scale displacements. In this way, the dimension of the conformational space to be sampled is heavily reduced. This methodology is especially suited to incorporate target flexibility at the backbone level. In this chapter, the main components of normal mode-based approaches in the context of ensemble docking are presented and explained, including the theoretical and practical considerations needed for the successful development and implementation of this methodology.

  3. Development of an Inquiry-Based Learning Support System Based on an Intelligent Knowledge Exploration Approach

    Science.gov (United States)

    Wu, Ji-Wei; Tseng, Judy C. R.; Hwang, Gwo-Jen

    2015-01-01

    Inquiry-Based Learning (IBL) is an effective approach for promoting active learning. When inquiry-based learning is incorporated into instruction, teachers provide guiding questions for students to actively explore the required knowledge in order to solve the problems. Although the World Wide Web (WWW) is a rich knowledge resource for students to…

  4. Opportunistic splitting for scheduling using a score-based approach

    KAUST Repository

    Rashid, Faraan

    2012-06-01

    We consider the problem of scheduling a user in a multi-user wireless environment in a distributed manner. The opportunistic splitting algorithm is applied to find the best group of users without reporting the channel state information to the centralized scheduler. The users find the best among themselves while requiring just a ternary feedback from the common receiver at the end of each mini-slot. The original splitting algorithm is modified to handle users with asymmetric channel conditions. We use a score-based approach with the splitting algorithm to introduce time and throughput fairness while exploiting the multi-user diversity of the network. Analytical and simulation results are given to show that the modified score-based splitting algorithm works well as a fair scheduling scheme with good spectral efficiency and reduced feedback. © 2012 IEEE.

  5. Computational approaches to substrate-based cell motility

    Science.gov (United States)

    Ziebert, Falko; Aranson, Igor S.

    2016-07-01

    Substrate-based crawling motility of eukaryotic cells is essential for many biological functions, both in developing and mature organisms. Motility dysfunctions are involved in several life-threatening pathologies such as cancer and metastasis. Motile cells are also a natural realisation of active, self-propelled 'particles', a popular research topic in nonequilibrium physics. Finally, from the materials perspective, assemblies of motile cells and evolving tissues constitute a class of adaptive self-healing materials that respond to the topography, elasticity and surface chemistry of the environment and react to external stimuli. Although a comprehensive understanding of substrate-based cell motility remains elusive, progress has been achieved recently in its modelling on the whole-cell level. Here we survey the most recent advances in computational approaches to cell movement and demonstrate how these models improve our understanding of complex self-organised systems such as living cells.

  6. A model-data based systems approach to process intensification

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    In recent years process intensification (PI) has attracted much interest as a potential means of process improvement to meet the demands, such as, for sustainable production. A variety of intensified equipment are being developed that potentially creates options to meet these demands...... for focused validation of only the promising candidates in the second-stage. This approach, however, would be limited to intensification based on “known” unit operations, unless the PI process synthesis/design is considered at a lower level of aggregation, namely the phenomena level. That is, the model....... Here, established procedures for computer aided molecular design is adopted since combination of phenomena to form unit operations with desired objectives is, in principle, similar to combining atoms to form molecules with desired properties. The concept of the phenomena-based synthesis/design method...

  7. A Security Based Data Mining Approach in Data Grid

    CERN Document Server

    Vidhya, S

    2010-01-01

    Grid computing is the next logical step to distributed computing. Main objective of grid computing is an innovative approach to share resources such as CPU usage; memory sharing and software sharing. Data Grids provide transparent access to semantically related data resources in a heterogeneous system. The system incorporates both data mining and grid computing techniques where Grid application reduces the time for sending results to several clients at the same time and Data mining application on computational grids gives fast and sophisticated results to users. In this work, grid based data mining technique is used to do automatic allocation based on probabilistic mining frequent sequence algorithm. It finds frequent sequences for many users at a time with accurate result. It also includes the trust management architecture for trust enhanced security.

  8. Ontology mapping approach based on set & relation theory and OCL

    Institute of Scientific and Technical Information of China (English)

    QIAN Peng-fei; ZHANG Shen-sheng; LIU Ying-hua

    2009-01-01

    An ontology mapping approach based on set & relation theory and OCL is introduced, then an ontolo-gy mapping meta-model is established which is composed of ontology related elements, mapping related elements and definition rule related elements. This ontology mapping meta-model can be regarded as a unified mechanism to realize different kinds of ontology mappings. The powerful computation capability of set and relation theory and the flexible expressive capability of OCL can be used in the computation of ontology mapping meta-model to realize the unified mapping among different ontology models. Based on the mapping meta-model, a general mapping management framework is developed to provide a common mapping storage mechanism, some mapping APIs and mapping rule APIs.

  9. Chemical Abstracts Service approach to management of large data bases.

    Science.gov (United States)

    Huffenberger, M A; Wigington, R L

    1975-02-01

    When information handling is "the business," as it is at Chemical Abstract Service (CAS), the total organization must be involved in information management. Since 1967, when, as a result of long-range planning efforts, CAS adopted a "data-base approach" to management of both the processing system and the distribution of information files, CAS has been grappling with the problems of managing large collections of information in computer-based systems. This paper describes what has been done at CAS in the management of large files and what we see as necessary, as a result of our experience, to improve and complete the information management system that is the foundation of our production processes.

  10. A model-based approach to human identification using ECG

    Science.gov (United States)

    Homer, Mark; Irvine, John M.; Wendelken, Suzanne

    2009-05-01

    Biometrics, such as fingerprint, iris scan, and face recognition, offer methods for identifying individuals based on a unique physiological measurement. Recent studies indicate that a person's electrocardiogram (ECG) may also provide a unique biometric signature. Current techniques for identification using ECG rely on empirical methods for extracting features from the ECG signal. This paper presents an alternative approach based on a time-domain model of the ECG trace. Because Auto-Regressive Integrated Moving Average (ARIMA) models form a rich class of descriptors for representing the structure of periodic time series data, they are well-suited to characterizing the ECG signal. We present a method for modeling the ECG, extracting features from the model representation, and identifying individuals using these features.

  11. Copula-Based Approach to Synthetic Population Generation

    Science.gov (United States)

    Kim, Deok-Soo

    2016-01-01

    Generating synthetic baseline populations is a fundamental step of agent-based modeling and simulation, which is growing fast in a wide range of socio-economic areas including transportation planning research. Traditionally, in many commercial and non-commercial microsimulation systems, the iterative proportional fitting (IPF) procedure has been used for creating the joint distribution of individuals when combining a reference joint distribution with target marginal distributions. Although IPF is simple, computationally efficient, and rigorously founded, it is unclear whether IPF well preserves the dependence structure of the reference joint table sufficiently when fitting it to target margins. In this paper, a novel method is proposed based on the copula concept in order to provide an alternative approach to the problem that IPF resolves. The dependency characteristic measures were computed and the results from the proposed method and IPF were compared. In most test cases, the proposed method outperformed IPF in preserving the dependence structure of the reference joint distribution. PMID:27490692

  12. GPC Using a Delta-Domain Emulator-Based Approach

    DEFF Research Database (Denmark)

    Lauritsen, Morten Bach; Jensen, Morten Rostgaard; Poulsen, Niels Kjølstad

    1997-01-01

    This paper describes new approaches to generalized predictive control formulated in the delta (delta) domain. A new delta-domain version of the continuous-time emulator-based predictor is presented. It is shown to contain the optimal discrete-time predictor based on incomplete information...... as a special case. Usually, a good estimate is obtained in a much longer range of samples than obtained by the optimal predictor of the same complexity. This is particularly advantageous at fast sampling rates where a `conventional' predictor is bound to become very computationally demanding. Two controllers...... are considered: one having a well-defined limit as the sampling period tends to zero, the other being a close approximation to the conventional discrete-time GPC. Both algorithms are discrete in nature and well-suited for adaptive control. The fact that delta-domain models are used does not introduce...

  13. An annotation based approach to support design communication

    CERN Document Server

    Hisarciklilar, Onur

    2007-01-01

    The aim of this paper is to propose an approach based on the concept of annotation for supporting design communication. In this paper, we describe a co-operative design case study where we analyse some annotation practices, mainly focused on design minutes recorded during project reviews. We point out specific requirements concerning annotation needs. Based on these requirements, we propose an annotation model, inspired from the Speech Act Theory (SAT) to support communication in a 3D digital environment. We define two types of annotations in the engineering design context, locutionary and illocutionary annotations. The annotations we describe in this paper are materialised by a set of digital artefacts, which have a semantic dimension allowing express/record elements of technical justifications, traces of contradictory debates, etc. In this paper, we first clarify the semantic annotation concept, and we define general properties of annotations in the engineering design context, and the role of annotations in...

  14. A TQCS-based Scheduling Approach for Manufacturing Grid

    Institute of Scientific and Technical Information of China (English)

    LIU Li-lan; YU Tao; CAO Hong-wu; SHI Zhan-bei

    2004-01-01

    With Open Grid Service Architecture (OGSA) as system framework, and Globus Toolkit3.0 (GT3) as developing tools, Manufacturing Grid (MG) is proposed in this research to realize resource sharing and collaborative working among manufacturing resources, and task scheduling is one of the most critical components in this system. Nevertheless, the Globus Resource Allocation Manager (GRAM) does not provide scheduling system by default, and traditional performance-guided or economy-guided schedulers cannot satisfy our needs in MG. So, in this paper, a TQCS (Time, Quality, Cost, Service)-based scheduling approach is presented and the corresponding scheduler (Manufacturing Grid Task Scheduler, MGTS) is implemented with the functions of Global Process Planning (GPP) analyzing, resource discovery, resource selection, AHP (Analytic Hierarchy Process)-based resource mapping, and fault-tolerant handling. Furthermore, the application architecture is depicted at the end of the paper to illustrate the utilization of our scheduler.

  15. The ROI CT problem: a shearlet-based regularization approach

    Science.gov (United States)

    Bubba, T. A.; Porta, F.; Zanghirati, G.; Bonettini, S.

    2016-10-01

    The possibility to significantly reduce the X-ray radiation dose and shorten the scanning time is particularly appealing, especially for the medical imaging community. Region- of-interest Computed Tomography (ROI CT) has this potential and, for this reason, is currently receiving increasing attention. Due to the truncation of projection images, ROI CT is a rather challenging problem. Indeed, the ROI reconstruction problem is severely ill-posed in general and naive local reconstruction algorithms tend to be very unstable. To obtain a stable and reliable reconstruction, under suitable noise circumstances, we formulate the ROI CT problem as a convex optimization problem with a regularization term based on shearlets, and possibly nonsmooth. For the solution, we propose and analyze an iterative approach based on the variable metric inexact line-search algorithm (VMILA). The reconstruction performance of VMILA is compared against different regularization conditions, in the case of fan-beam CT simulated data. The numerical tests show that our approach is insensitive to the location of the ROI and remains very stable also when the ROI size is rather small.

  16. A Block-Based Regularized Approach for Image Interpolation

    Directory of Open Access Journals (Sweden)

    Li Chen

    2014-01-01

    Full Text Available This paper presents a new efficient algorithm for image interpolation based on regularization theory. To render a high-resolution (HR image from a low-resolution (LR image, classical interpolation techniques estimate the missing pixels from the surrounding pixels based on a pixel-by-pixel basis. In contrast, the proposed approach formulates the interpolation problem into the optimization of a cost function. The proposed cost function consists of a data fidelity term and regularization functional. The closed-form solution to the optimization problem is derived using the framework of constrained least squares minimization, by incorporating Kronecker product and singular value decomposition (SVD to reduce the computational cost of the algorithm. The effect of regularization on the interpolation results is analyzed, and an adaptive strategy is proposed for selecting the regularization parameter. Experimental results show that the proposed approach is able to reconstruct high-fidelity HR images, while suppressing artifacts such as edge distortion and blurring, to produce superior interpolation results to that of conventional image interpolation techniques.

  17. An approach towards problem-based learning in virtual space.

    Science.gov (United States)

    Freudenberg, Lutz S; Bockisch, Andreas; Beyer, Thomas

    2010-01-01

    Problem-based learning (PBL) is an established and efficient approach to sustainable teaching. Here, we describe translation of PBL into the virtual classroom thereby offering novel teaching aspects in the field of Nuclear Medicine. Our teaching approach is implemented on a "moodle" platform and consists of 2 modules: complementary seminar teaching materials and a virtual PBL-classroom, which can be attended via Skype.Over the course of 4 semesters 539 students have accessed our teaching platform. 21 students have participated in the PBL seminar (module 2). After resolving some minor technical difficulties our virtual seminars have evolved into a forum of intense studies, whereby the participating students have learned to become more independent along the workup of the teaching cases. This was reflected in the results of the intra-group presentations and discussions.Quantitative and qualitative evaluation of our moodle-based PBL platform indicates an increasing level of acceptance and enthusiasm by the students. This has initiated discussions about opening our PBL concept to a wider audience within the university and beyond the Nuclear Medicine specialty.

  18. SPATIAL DATA INTEGRATION USING ONTOLOGY-BASED APPROACH

    Directory of Open Access Journals (Sweden)

    S. Hasani

    2015-12-01

    Full Text Available In today's world, the necessity for spatial data for various organizations is becoming so crucial that many of these organizations have begun to produce spatial data for that purpose. In some circumstances, the need to obtain real time integrated data requires sustainable mechanism to process real-time integration. Case in point, the disater management situations that requires obtaining real time data from various sources of information. One of the problematic challenges in the mentioned situation is the high degree of heterogeneity between different organizations data. To solve this issue, we introduce an ontology-based method to provide sharing and integration capabilities for the existing databases. In addition to resolving semantic heterogeneity, better access to information is also provided by our proposed method. Our approach is consisted of three steps, the first step is identification of the object in a relational database, then the semantic relationships between them are modelled and subsequently, the ontology of each database is created. In a second step, the relative ontology will be inserted into the database and the relationship of each class of ontology will be inserted into the new created column in database tables. Last step is consisted of a platform based on service-oriented architecture, which allows integration of data. This is done by using the concept of ontology mapping. The proposed approach, in addition to being fast and low cost, makes the process of data integration easy and the data remains unchanged and thus takes advantage of the legacy application provided.

  19. Subway Train Braking System: A Fuzzy Based Hardware Approach

    Directory of Open Access Journals (Sweden)

    Mamun B.I. Reaz

    2011-01-01

    Full Text Available Problem statement: Automated subway train-braking system require perfection, efficiency and fast response. In order to cope with this concerns, an appropriate algorithm need to be developed which need to be implemented in hardware for faster response. Approach: In this research, the FPGA realization of fuzzy based subway train braking system has been presented on an Alter FLEX10K device to provide an accurate and increased speed of convergence of the network. The fuzzy based subway train braking system is comprised of fusilier, inference, rule selector and defuzzifier modules. Sixteen rules are identified for the rule selector module. After determining the membership functions and its fuzzy variables, the Max-Min Composition method and Madman-Min implication operator are used for the inference module and the Centre of Gravity method is used for the defuzzification module. Each module is modeled individually using behavioral VHDL. The layers are then connected using structural VHDL. Two 8-bit and one 8-bit unsigned digital signals are used for input and output respectively. Six ROMs are defined in order to decrease the chances of processing and increasing the throughput of the system. Results: Functional simulations were commenced to verify the functionality of the individual modules and the system as well. We have validated the hardware implementation of the proposed approach through comparison, verification and analysis. The design has utilized 2372 units of LC with a system frequency of 139.8MHz. Conclusion: In this research, the FPGA realization of fuzzy brake system of subway train has been successfully implemented with minimum usage of logic cells. The validation study with C model shows that the hardware model is appropriate and the hardware approach shows faster and accurate response with full automatic control.

  20. LEADING CHANGES IN ASSESSMENT USING AN EVIDENCE BASED APPROACH

    Directory of Open Access Journals (Sweden)

    J. O. Macaulay

    2015-08-01

    Full Text Available Introduction and objectivesIt is has been widely accepted that assessment of learning is a critical component of education and that assessment drives/guides student learning through shaping study habits and student approaches to learning. However, although most academics would agree that assessment is a critical aspect of their roles as teachers it is often an aspect of teaching that is regarded more as an additional task rather than an integral component of the teaching/learning continuum. An additional impediment to high quality assessment is the non-evidence based-approach to the decision making process. The overall aim of this project was to improve the quality of assessment in Biochemistry and Molecular Biology undergraduate education by promoting high quality assessment.Materials and methodsTo do this we developed and trialled an audit tool for mapping assessment practices. The audit tool was designed to gather data on current assessment practices and identify areas of good practice in which assessment aligned with the learning objectives and areas in need of improvement. This evidence base will then be used to drive change in assessment.Results and conclusionsUsing the assessment mapping tool we have mapped the assessment regime in a Biochemistry and Molecular Biology major at Monash University. Criteria used included: assessment type, format, timing, assessors, provision of feedback, level of learning (Bloom’s, approaches taken to planning assessment. We have mapped assessment of content and the systematic development of higher order learning and skills progression throughout the program of study. The data has enabled us to examine the assessment at unit (course level as well as the vertical development across the major. This information is now being used to inform a review of the units and the major.

  1. Business Process Management – A Traditional Approach Versus a Knowledge Based Approach

    Directory of Open Access Journals (Sweden)

    Roberto Paiano

    2015-12-01

    Full Text Available The enterprise management represents a heterogeneous aggregate of both resources and assets that need to be coordinated and orchestrated in order to reach the goals related to the business mission. Influences and forces that may influence this process, and also for that they should be considered, are not concentrated in the business environment, but they are related to the entireoperational context of a company. For this reason, business processes must be the most versatile and flexible with respect to the changes that occur within the whole operational context of a company.Considering the supportive role that information systems play in favour of Business Process Management - BPM, it is also essential to implement a constant, continuous and quick mechanism for the information system alignment with respect to the evolution followed by business processes.In particular, such mechanism must intervene on BPM systems in order to keep them aligned and compliant with respect to both the context changes and the regulations. In order to facilitate this alignment mechanism, companies are already referring to the support offered by specific solutions, such as knowledge bases. In this context, a possible solution might be the approach we propose, which is based on a specific framework called Process Management System. Our methodology implements a knowledge base support for business experts, which is not limited to the BPM operating phases, but includes also the engineering and prototyping activities of the corresponding information system. This paper aims to compare and evaluate a traditional BPM approach with respect to theapproach we propose. In effect, such analysis aims to emphasize the lack of traditional methodology especially with respect to the alignment between business processes and information systems, along with their compliance with context domain and regulations.

  2. A Comparison of Routing Protocol for WSNs: Redundancy Based Approach A Comparison of Routing Protocol for WSNs: Redundancy Based Approach

    Directory of Open Access Journals (Sweden)

    Anand Prakash

    2014-03-01

    Full Text Available Wireless Sensor Networks (WSNs with their dynamic applications gained a tremendous attention of researchers. Constant monitoring of critical situations attracted researchers to utilize WSNs at vast platforms. The main focus in WSNs is to enhance network localization as much as one could, for efficient and optimal utilization of resources. Different approaches based upon redundancy are proposed for optimum functionality. Localization is always related with redundancy of sensor nodes deployed at remote areas for constant and fault tolerant monitoring. In this work, we propose a comparison of classic flooding and the gossip protocol for homogenous networks which enhances stability and throughput quiet significantly.  

  3. An Integrated Approach for Image Retrieval based on Content

    Directory of Open Access Journals (Sweden)

    Kavita Choudhary

    2010-05-01

    Full Text Available The difficulties faced in an image retrieval system used for browsing, searching and retrieving of image in an image databases cannot be underestimated also the efficient management of the rapidly expanding visual information has become an urgent problem in science and technology. This requirement formed the driving force behind the emergence of image retrieval techniques. Image retrieval based on content also called content based image retrieval, is a technique which uses the visual contents to search an image in the scale database. This Image retrieval technique integrate both low-level visual features, addressing the more detailed perceptual aspects, and high-level semantic features underlying the more general conceptual aspects of visual data. In connection with this Content Based Image Retrieval is a technology that is being developed to address different application areas, remote sensing, geographic information systems, and weather forecasting, architectural and engineering design, multimedia documents for digital libraries. In this paper we present an approach that significantly automates the retrieving process by relying on image analysis techniques that are based on image visual features like color with spatial information, texture and shape.

  4. A decision analytic approach to exposure-based chemical prioritization.

    Directory of Open Access Journals (Sweden)

    Jade Mitchell

    Full Text Available The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient data are available, the hazard and exposure data necessary to assess risks adequately are unavailable for the vast majority of chemicals in commerce. The US Environmental Protection Agency has initiated the ExpoCast Program to develop tools for rapid chemical evaluation based on potential for exposure. In this context, a model is presented in which chemicals are evaluated based on inherent chemical properties and behaviorally-based usage characteristics over the chemical's life cycle. These criteria are assessed and integrated within a decision analytic framework, facilitating rapid assessment and prioritization for future targeted testing and systems modeling. A case study outlines the prioritization process using 51 chemicals. The results show a preliminary relative ranking of chemicals based on exposure potential. The strength of this approach is the ability to integrate relevant statistical and mechanistic data with expert judgment, allowing for an initial tier assessment that can further inform targeted testing and risk management strategies.

  5. Query Based Approach Towards Spam Attacks Using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Gaurav Kumar Tak

    2010-10-01

    Full Text Available Currently, spam and scams are passive attack over the inbox which can initiated to steal someconfidential information, to spread Worms, Viruses, Trojans, cookies and Sometimes they are used forphishing attacks. Spam mails are the major issue over mail boxes as well as over the internet. Spam mailscan be the cause of phishing attack, hacking of banking accounts, attacks on confidential data. Spammingis growing at a rapid rate since sending a flood of mails is easy and very cheap. Spam mails disturb themind-peace, waste time and consume various resources e.g., memory space and network bandwidth, sofiltering of spam mails is a big issue in cyber security.This paper presents an novel approach of spam filtering which is based on some query generatedapproach on the knowledge base and also use some artificial neural network methods to detect the spammails based on their behavior. analysis of the mail header, cross validation. Proposed methodologyincludes the 7 several steps which are well defined and achieve the higher accuracy. It works well with allkinds of spam mails (text based spam as well as image spam. Our tested data and experiments resultsshows promising results, and spam’s are detected out at least 98.17 % with 0.12% false positive.

  6. An algebraic approach to revising propositional rule-based knowledge bases

    Institute of Scientific and Technical Information of China (English)

    LUAN ShangMin; DAI GuoZhong

    2008-01-01

    One of the important topics in knowledge base revision is to introduce an efficient implementation algorithm. Algebraic approaches have good characteristics and implementation method; they may be a choice to solve the problem. An algebraic approach is presented to revise propositional rule-based knowledge bases in this paper. A way is firstly introduced to transform a propositional rule-based knowl- edge base into a Petri net. A knowledge base is represented by a Petri net, and facts are represented by the initial marking. Thus, the consistency check of a knowledge base is equivalent to the reachability problem of Petri nets. The reachability of Petri nets can be decided by whether the state equation has a solution; hence the con- sistency check can also be implemented by algebraic approach. Furthermore, al- gorithms are introduced to revise a propositional rule-based knowledge base, as well as extended logic programming. Compared with related works, the algorithms presented in the paper are efficient, and the time complexities of these algorithms are polynomial.

  7. Rule based fuzzy logic approach for classification of fibromyalgia syndrome.

    Science.gov (United States)

    Arslan, Evren; Yildiz, Sedat; Albayrak, Yalcin; Koklukaya, Etem

    2016-06-01

    Fibromyalgia syndrome (FMS) is a chronic muscle and skeletal system disease observed generally in women, manifesting itself with a widespread pain and impairing the individual's quality of life. FMS diagnosis is made based on the American College of Rheumatology (ACR) criteria. However, recently the employability and sufficiency of ACR criteria are under debate. In this context, several evaluation methods, including clinical evaluation methods were proposed by researchers. Accordingly, ACR had to update their criteria announced back in 1990, 2010 and 2011. Proposed rule based fuzzy logic method aims to evaluate FMS at a different angle as well. This method contains a rule base derived from the 1990 ACR criteria and the individual experiences of specialists. The study was conducted using the data collected from 60 inpatient and 30 healthy volunteers. Several tests and physical examination were administered to the participants. The fuzzy logic rule base was structured using the parameters of tender point count, chronic widespread pain period, pain severity, fatigue severity and sleep disturbance level, which were deemed important in FMS diagnosis. It has been observed that generally fuzzy predictor was 95.56 % consistent with at least of the specialists, who are not a creator of the fuzzy rule base. Thus, in diagnosis classification where the severity of FMS was classified as well, consistent findings were obtained from the comparison of interpretations and experiences of specialists and the fuzzy logic approach. The study proposes a rule base, which could eliminate the shortcomings of 1990 ACR criteria during the FMS evaluation process. Furthermore, the proposed method presents a classification on the severity of the disease, which was not available with the ACR criteria. The study was not limited to only disease classification but at the same time the probability of occurrence and severity was classified. In addition, those who were not suffering from FMS were

  8. Simulation and Non-Simulation Based Human Reliability Analysis Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Boring, Ronald Laurids [Idaho National Lab. (INL), Idaho Falls, ID (United States); Shirley, Rachel Elizabeth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Joe, Jeffrey Clark [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mandelli, Diego [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-12-01

    Part of the U.S. Department of Energy’s Light Water Reactor Sustainability (LWRS) Program, the Risk-Informed Safety Margin Characterization (RISMC) Pathway develops approaches to estimating and managing safety margins. RISMC simulations pair deterministic plant physics models with probabilistic risk models. As human interactions are an essential element of plant risk, it is necessary to integrate human actions into the RISMC risk model. In this report, we review simulation-based and non-simulation-based human reliability assessment (HRA) methods. Chapter 2 surveys non-simulation-based HRA methods. Conventional HRA methods target static Probabilistic Risk Assessments for Level 1 events. These methods would require significant modification for use in dynamic simulation of Level 2 and Level 3 events. Chapter 3 is a review of human performance models. A variety of methods and models simulate dynamic human performance; however, most of these human performance models were developed outside the risk domain and have not been used for HRA. The exception is the ADS-IDAC model, which can be thought of as a virtual operator program. This model is resource-intensive but provides a detailed model of every operator action in a given scenario, along with models of numerous factors that can influence operator performance. Finally, Chapter 4 reviews the treatment of timing of operator actions in HRA methods. This chapter is an example of one of the critical gaps between existing HRA methods and the needs of dynamic HRA. This report summarizes the foundational information needed to develop a feasible approach to modeling human interactions in the RISMC simulations.

  9. Ray-Based Approach to Skeletal Muscle Perfusion Measurement on Interventional X-ray Systems

    NARCIS (Netherlands)

    Giordano, M.; Vonken, E.J.; Bertram, M.; Mali, W.; Viergever, M.A.; Neukirchen, C.

    2012-01-01

    Purpose: Quantitative assessment of tissue perfusion by imaging methods could improve outcome control during treatment of peripheral vascular disease. Currently, revascularization treatments are assessedby planar angiography which only allows for qualitative inspection of blood flow in vessels. In t

  10. In vivo flow cytometry and time-resolved near-IR angiography and lymphography

    Science.gov (United States)

    Galanzha, Ekaterina I.; Tuchin, Valery V.; Brock, Robert W.; Zharov, Vladimir P.

    2007-05-01

    Integration of photoacoustic and photothermal techniques with high-speed, high-resolution transmission and fluorescence microscopy shows great potential for in vivo flow cytometry and indocyanine green (ICG) near-infrared (IR) angiography of blood and lymph microvessels. In particular, the capabilities of in vivo flow cytometry using rat mesentery and nude mouse ear models are demonstrated for real-time quantitative detection of circulating and migrating individual blood and cancer cells in skin, mesentery, lymph nodes, liver, kidney; studying vascular dynamics with a focus on lymphatics; monitoring cell traffic between blood and lymph systems; high-speed imaging of cell deformability in flow; and label-free real-time monitoring of single cell extravasation from blood vessel lumen into tissue. As presented, the advantages of ICG IR-angiography include estimation of time resolved dye dynamics (appearance and clearance) in blood and lymph microvessels using fluorescent and photoacoustic modules of the integrated technique. These new approaches are important for monitoring and quantifying metastatic and apoptotic cells; comparative measurements of plasma and cell velocities; analysis of immune responses; monitoring of circulating macromolecules, chylomicrons, bacteria, viruses and nanoparticles; molecular imaging. In the future, we believe that the integrated technique presented will have great potential for translation to early disease diagnoses (e.g. cancer) or assessment of innovative therapeutic interventions in humans.

  11. Solid-state fluoroscopic imager for high-resolution angiography: parallel-cascaded linear systems analysis.

    Science.gov (United States)

    Vedantham, Srinivasan; Karellas, Andrew; Suryanarayanan, Sankararaman

    2004-05-01

    Cascaded linear systems based modeling techniques have been used in the past to predict important system parameters that have a direct impact on image quality. Such models are also useful in optimizing system parameters to improve image quality. In this work, detailed analysis of a solid-state fluoroscopic imaging system intended for high-resolution angiography is presented with the use of such a model. The imaging system analyzed through this model uses four 8 x 8 cm three-side buttable interlined charge-coupled devices (CCDs) specifically designed for high-resolution angiography and tiled in a seamless fashion to achieve a field of view (FOV) of 16 x 16 cm. Larger FOVs can be achieved by tiling more CCDs in a similar manner. The system employs a CsI:Tl scintillator coupled to the CCDs by straight (nontapering) fiberoptics and can potentially be operated in 78, 156, or 234 microm pixel pitch modes. The system parameters analyzed through this model include presampling modulation transfer function, noise power spectrum, and detective quantum efficiency (DQE). The results of the simulations performed indicate that DQE(0) in excess of 0.6 is achievable, with the imager operating at 156 microm pixel pitch, 30 frames/s, and employing a 450-microm-thick CsI:Tl scintillator, even at a low fluoroscopic exposure rate of 1 microR/frame. Further, at a nominal fluoroscopic exposure rate of 2.5 microR/frame there was no noticeable degradation of the DQE even at the 78 microm pixel pitch mode suggesting that it is feasible to perform high-resolution angiography hitherto unattainable in clinical practice.

  12. A Learning Object Approach To Evidence based learning

    Directory of Open Access Journals (Sweden)

    Zabin Visram

    2005-06-01

    Full Text Available This paper describes the philosophy, development and framework of the body of elements formulated to provide an approach to evidence-based learning sustained by Learning Objects and web based technology Due to the demands for continuous improvement in the delivery of healthcare and in the continuous endeavour to improve the quality of life, there is a continuous need for practitioner's to update their knowledge by accomplishing accredited courses. The rapid advances in medical science has meant increasingly, there is a desperate need to adopt wireless schemes, whereby bespoke courses can be developed to help practitioners keep up with expanding knowledge base. Evidently, without current best evidence, practice risks becoming rapidly out of date, to the detriment of the patient. There is a need to provide a tactical, operational and effective environment, which allows professional to update their education, and complete specialised training, just-in-time, in their own time and location. Following this demand in the marketplace the information engineering group, in combination with several medical and dental schools, set out to develop and design a conceptual framework which form the basis of pioneering research, which at last, enables practitioner's to adopt a philosophy of life long learning. The body and structure of this framework is subsumed under the term Object oriented approach to Evidence Based learning, Just-in-time, via Internet sustained by Reusable Learning Objects (The OEBJIRLO Progression. The technical pillars which permit this concept of life long learning are pivoted by the foundations of object oriented technology, Learning objects, Just-in-time education, Data Mining, intelligent Agent technology, Flash interconnectivity and remote wireless technology, which allow practitioners to update their professional skills, complete specialised training which leads to accredited qualifications. This paper sets out to develop and

  13. [Food based approaches to improve vitamin and mineral nutrition adequacy].

    Science.gov (United States)

    Oyarzún, M T; Uauy, R; Olivares, S

    2001-03-01

    This paper, using the nutrient density concept and the development of Food-Based Dietary Guidelines (FBDG), explores the nutritional adequacy of food patterns based on the main staples around the world--maize, wheat, rice and potato. The nutritional adequacy of the vitamins A, C, folates and the minerals iron, zinc and calcium in diets composed by these staples is analyzed. Projected diets modified by the addition of foods high in vitamins and minerals, based on food table composition information, are analyzed for changes in nutritional adequacy, in order to cover the nutritional requirements of all family members. This theoretical exercise shows that diets diversified by the addition of relatively small quantities (27-70 g) of foods like fruits, vegetables, legumes and meat improve substantially the nutritional adequacy of the vitamins A, C, folates, iron and zinc. In the case of calcium, the addition of a dairy source becomes essential. From the practical point of view, the implementation of the food based approach requires a national effort in order to support the production of nutrient rich foods and to promote consciousness of nutrient bioavailability, so that people may obtain all nutrient potential from foods. Simultaneously, the need of fortification programs at the national level is recognized. This is the case for critical nutrients, where requirements might be above the potential in available foods. A similar situation occurs in the case of vulnerable groups like pregnant women and infants, who need supplementation to ensure nutritional adequacy of their diets. In conclusion, the use of FBDG is a good alternative for improving the nutritional adequacy of diets based predominantly on staple foods. However, food fortification and supplementation programs directed to vulnerable groups are necessary and complementary practices to the FBDG implementation.

  14. The Arts-Based Research’ approach: hints for educational research

    Directory of Open Access Journals (Sweden)

    Monica Pentassuglia

    2017-01-01

    Full Text Available The last two decades have seen a growing interest on the different ways of knowing in all the fields. Although some research has highlights the importance of this topic, there is still very little scientific understanding about this process. The first serious discussions and analyses of the construction of knowledge emerged during the 1900s. In Humanities field, questions have been raised about the use of traditional research paradigm considered unable for the understanding of these complex subjects. In this perspective, this article provided an important opportunity to advance the understanding of new research paths that not only overturn the classical perspective of research, but also allow us to reformulate and reinvent strategies, tools, and forms of representations of research findings. This article considers the implications of the approach of Arts-Based Research (ABR and deeply of dance-based methods for educational research.L’approccio dell’Arts-Based Research: quali spunti per la ricerca educativa?Tra i temi che più si sono imposti, negli ultimi anni, all’attenzione dei ricercatori, è il problema dei processi di costruzione della conoscenza ad aver catalizzato su di sé la maggior parte degli studi; è soprattutto in ambito umanistico che cresce l’idea secondo cui i classici paradigmi di ricerca non siano in grado di comprendere ed indagare la complessità dei fenomeni esplorati. Sulla scia di tali necessità, il presente contributo intende approfondire l’approccio dell’Arts-Based Research (ABR ed in particolare dei dance-based methods nel campo della ricerca educativa che negli ultimi anni sta contribuendo a capovolgere l’impostazione classica del processo di ricerca a favore di nuovi percorsi in grado di utilizzare le potenzialità dell’Arte secondo nuove prospettive.

  15. Surgeon's view of the skull base from the lateral approach.

    Science.gov (United States)

    Goldenberg, R A

    1984-12-01

    This paper presents the surgical anatomy of the skull base and infratemporal fossa. The information has been derived from the author's own experience in surgical and cadaver dissection, standard anatomical references, and selected experience of other skull base surgeons. Because the lateral approach has become the utilitarian method of exposure, the intricate detailed anatomy is demonstrated from this view at five levels of dissection, so the surgeon may gain a practical understanding of the surgical relationship of critical structures. Consistent anatomical landmarks can be used by the surgeon in the location of these critical structures. The styloid process, sphenoidal spine, and middle meningeal artery identify the internal carotid artery as it enters the carotid canal. The bony or fibrous septum that divides the jugular foramen into neural and vascular compartments may be used to better identify nerves IX, X, and XI. The zygomatic root is useful for location of the middle fossa dura. The lateral pterygoid plate leads directly to the foramen ovale. The increased precision of dissection permitted by use of the microscope requires an increased level of knowledge of anatomical structures in this area. It is hoped that the information presented in this paper will assist surgeons in the meticulous and thorough removal of skull base tumors and in the preservation of neural and vascular structures that are presently being sacrificed.

  16. Modeling the crop transpiration using an optimality-based approach

    Institute of Scientific and Technical Information of China (English)

    Stanislaus; J.Schymanski; Murugesu; Sivapalan

    2008-01-01

    Evapotranspiration constitutes more than 80% of the long-term water balance in Northern China.In this area,crop transpiration due to large areas of agriculture and irrigation is responsible for the majority of evapotranspiration.A model for crop transpiration is therefore essential for estimating the agricultural water consumption and understanding its feedback to the environment.However,most existing hydrological models usually calculate transpiration by relying on parameter calibration against local observations,and do not take into account crop feedback to the ambient environment.This study presents an optimality-based ecohydrology model that couples an ecological hypothesis,the photosynthetic process,stomatal movement,water balance,root water uptake and crop senescence,with the aim of predicting crop characteristics,CO2 assimilation and water balance based only on given meteorological data.Field experiments were conducted in the Weishan Irrigation District of Northern China to evaluate performance of the model.Agreement between simulation and measurement was achieved for CO2 assimilation,evapotranspiration and soil moisture content.The vegetation optimality was proven valid for crops and the model was applicable for both C3 and C4 plants.Due to the simple scheme of the optimality-based approach as well as its capability for modeling dynamic interactions between crops and the water cycle without prior vegetation information,this methodology is potentially useful to couple with the distributed hydrological model for application at the watershed scale.

  17. Team-Based Learning: A New Approach Toward Improving Education

    Directory of Open Access Journals (Sweden)

    Rita Rezaee

    2016-11-01

    Full Text Available  Team-based learning is designed to provide students with both conceptual and procedural knowledge, aiming to enhance active learning and critical thinking. In the present study, team-based learning and lecture methods in teaching the “hospital organization and management” course among hospital management students were compared. This quasi-experimental study was conducted on 25 undergraduate students of management. Teaching sessions were divided into two parts. The first part was taught with interactive lectures and the second part with team-based learning method. The students' knowledge was measured before, immediately and two months (late post-test after teaching. Finally, the mean scores of the final exam and students' satisfaction towards the methods of teaching were measured. There was an improvement in test scores of the students after the TBL sessions when compared to the test scores after lecture sessions (P<0.001. Also, TBL group had significantly a higher amount of knowledge retention compared to the lecture group (P<0.001, but no significant relationship was found between the mean scores of the final exam in the TBL and lecture groups (P=0.116. Finally, the majority of the respondents were more satisfied with TBL sessions compared to the ones held through lecture (P=0.037. The results indicated that TBL provides a better outcome for students. We found that the TBL approach allowed us to create an active learning environment that contributed to the improvement of the students’ performances.

  18. ARABIC-MALAY MACHINE TRANSLATION USING RULE-BASED APPROACH

    Directory of Open Access Journals (Sweden)

    Ahmed Jumaa Alsaket

    2014-01-01

    Full Text Available Arabic machine translation has been taking place in machine translation projects in recent years. This study concentrates on the translation of Arabic text to its equivalent in Malay language. The problem of this research is the syntactic and morphological differences between Arabic and Malay adjective sentences. The main aim of this study is to design and develop Arabic-Malay machine translation model. First, we analyze the adjective role in the Arabic and Malay languages. Based on this analysis, we identify the transfer bilingual rules form source language to target language so that the translation of source language to target language can be performed by computers successfully. Then, we build and implement a machine translation prototype called AMTS to translate from Arabic to Malay based on rule based approach. The system is evaluated on set of simple Arabic sentences. The techniques used to evaluate the correctness of the system translation are the BLEU metric algorithm and the human judgment. The results of the BLEU algorithm show that the AMTS system performs better than Google in the translation of Arabic sentences into Malay. In addition, the average accuracy given by human judges is 92.3% for our system and 75.3% for Google.

  19. Structure-based molecular modeling approaches to GPCR oligomerization.

    Science.gov (United States)

    Kaczor, Agnieszka A; Selent, Jana; Poso, Antti

    2013-01-01

    Classical structure-based drug design techniques using G-protein-coupled receptors (GPCRs) as targets focus nearly exclusively on binding at the orthosteric site of a single receptor. Dimerization and oligomerization of GPCRs, proposed almost 30 years ago, have, however, crucial relevance for drug design. Targeting these complexes selectively or designing small molecules that affect receptor-receptor interactions might provide new opportunities for novel drug discovery. In order to study the mechanisms and dynamics that rule GPCRs oligomerization, it is essential to understand the dynamic process of receptor-receptor association and to identify regions that are suitable for selective drug binding, which may be determined with experimental methods such as Förster resonance energy transfer (FRET) or Bioluminescence resonance energy transfer (BRET) and computational sequence- and structure-based approaches. The aim of this chapter is to provide a comprehensive description of the structure-based molecular modeling methods for studying GPCR dimerization, that is, protein-protein docking, molecular dynamics, normal mode analysis, and electrostatics studies.

  20. DIGITAL ONCOLOGY PATIENT RECORD - HETEROGENEOUS FILE BASED APPROACH

    Directory of Open Access Journals (Sweden)

    Nikolay Sapundzhiev

    2010-12-01

    Full Text Available Introduction: Oncology patients need extensive follow-up and meticulous documentation. The aim of this study was to introduce a simple, platform independent file based system for documentation of diagnostic and therapeutic procedures in oncology patients and test its function.Material and methods: A file-name based system of the type M1M2M3.F2 was introduced, where M1 is a unique identifier for the patient, M2 is the date of the clinical intervention/event, M3 is an identifier for the author of the medical record and F2 is the specific software generated file-name extension.Results: This system is in use at 5 institutions, where a total of 11 persons on 14 different workstations inputted 16591 entries (files for 2370. The merge process was tested on 2 operating systems - when copied together all files sort up as expected by patient, and for each patient in a chronological order, providing a digital cumulative patient record, which contains heterogeneous file formats.Conclusion: The file based approach for storing heterogeneous digital patient related information is an reliable system, which can handle open-source, proprietary, general and custom file formats and seems to be easily scalable. Further development of software for automatic checks of the integrity and searching and indexing of the files is expected to produce a more user-friendly environment