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Sample records for angiography based approach

  1. Angiography

    International Nuclear Information System (INIS)

    The history of angiography is short, with its centennial approaching. A very brief review of milestones begins with the discovery of x-rays in 1895. Only a few months later contrast agents too toxic for human use were being injected into cadavers, severed limbs, and animals. The next major developments came in the late 1970s when percutaneous translumbar aortography and cerebral angiography were described. Contrast agents were now less toxic, and clinically useful angiography was a reality. In 1953 a technique for percutaneous vascular catheterization which formed the basis of many catheterization techniques to follow was described. In the 1970s the development of less invasive diagnostic methods such as computed tomography and diagnostic ultrasound decreased the indications for angiography, but newer interventional techniques such as embolization therapy and angioplasty have taken up the slack. Angiography remains the most important way to demonstrate vascular diseases graphically. Specific techniques such as angioplasty and digital subtraction angiography will be dealt with in other chapters. The authors hope to provide an overview of major areas of angiographic utilization. The basic techniques of arterial puncture and catheterization have been well described elsewhere

  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. Bolus characteristics based on Magnetic Resonance Angiography

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    Bi Xiaoming

    2006-10-01

    Full Text Available Abstract Background A detailed contrast bolus propagation model is essential for optimizing bolus-chasing Computed Tomography Angiography (CTA. Bolus characteristics were studied using bolus-timing datasets from Magnetic Resonance Angiography (MRA for adaptive controller design and validation. Methods MRA bolus-timing datasets of the aorta in thirty patients were analyzed by a program developed with MATLAB. Bolus characteristics, such as peak position, dispersion and bolus velocity, were studied. The bolus profile was fit to a convolution function, which would serve as a mathematical model of bolus propagation in future controller design. Results The maximum speed of the bolus in the aorta ranged from 5–13 cm/s and the dwell time ranged from 7–13 seconds. Bolus characteristics were well described by the proposed propagation model, which included the exact functional relationships between the parameters and aortic location. Conclusion The convolution function describes bolus dynamics reasonably well and could be used to implement the adaptive controller design.

  4. The Hunter Pulmonary Angiography Catheter for a Brachiocephalic Vein Approach

    International Nuclear Information System (INIS)

    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

  5. Percutaneous trans-ulnar artery approach for coronary angiography and angioplasty; A case series study

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    Roghani-Dehkordi, Farshad; Hadizadeh, Mahmood; Hadizadeh, Fatemeh

    2015-01-01

    BACKGROUND Coronary angiography is the gold standard method for diagnosis of coronary heart disease and usually performed by femoral approach that has several complications. To reduce these complications, upper extremity approach is increasingly used and is becoming preferred access site by many interventionists. Although radial approach is relatively well studied, safety, feasibility and risk of applying ulnar approach in not clearly known yet. METHODS We followed 97 patients (man = 56%, mean ± standard deviation of age = 57 ± 18) who had undergone coronary angiography or angioplasty via ulnar approach for 6-10 months and recorded their outcomes. RESULTS In 97 patients out of 105 ones (92.38%), procedure through ulnar access were successfully done. Unsuccessful puncture (3 patients), wiring (2 patients), passing of sheet (2 patients), and anatomically unsuitable ulnar artery (1 patient) were the reasons of failure. In 94 patients (89.52%), the angiography and angioplasty was done without any complications. Five patients (5.1%) hematoma and 11 patients (11%) experienced low-grade pain that resolved with painkiller. No infection, amputation or need for surgery was reported. CONCLUSION This study demonstrated that ulnar access in our patients was a safe and practical approach for coronary angiography or angioplasty, without any major complication. Bearing in mind its high success rate, it can be utilized when a radial artery is not useful for the catheterization and in cases such as prior harvesting of the radial artery (in prior coronary artery bypass grafting). PMID:26715936

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

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    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

  7. Comparative Efficacy of Transradial Versus Transfemoral Approach for Coronary Angiography and Percutaneous Coronary Intervention.

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    Schussler, Jeffrey M; Vasudevan, Anupama; von Bose, Liana J; Won, Jane I; McCullough, Peter A

    2016-08-15

    Transradial artery (TRA) approach is associated with fewer vascular complications and reduced mortality in patients at high risk compared with transfemoral approach (TFA). The objective of our study was to compare the characteristics and outcomes of patients who had coronary angiography by TRA and TFA over the course of hospital implementation of this approach. We included 12,928 patients from Baylor University Medical Center and Baylor Heart and Vascular Hospital, Dallas, Texas, who underwent a coronary angiography from January 2008 to March 2015. To control for selection bias and the learning curve, a nested matched study design was used for patients with percutaneous coronary intervention (PCI) with TRA patients matched with TFA by age (±2 years) and calendar year of the procedure in a ratio of 1:3. TRA for PCI increased from nearly 0% in 2008 to 9% in 2014. Including patients from 2011 to 2015 for the analysis, patients with TFA were older (65 ± 12 vs 64 ± 11) and had lower mean body mass index (30 ± 7 vs 33 ± 9 kg/m(2)) than patients with TRA. Patients with TRA had less bleeding, dialysis, pseudoaneurysm, and access site hematomas than the patients with TRA (0.7% vs 0%; p = 0.02). By a conditional logistic regression, we observed fewer complications, readmissions, and in-hospital deaths among TRA patients than the matched TFA patients. In conclusion, patients undergoing angiography with/without PCI through TRA had fewer complications, readmissions, and a shorter length of hospital stay after procedure versus TFA at our hospital. PMID:27378143

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

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    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. Activity-based cost analysis in catheter-based angiography and interventional radiology

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    The aim of this study was to analyse the costs of the interventional radiology unit and to identify the cost factors in the different activities of catheter-based angiographies and interventional radiology. In 1999 the number of procedures in the interventional radiological unit at Tampere University Hospital was 2968; 1601 of these were diagnostic angiographies, 526 endovascular and 841 nonvascular interventions. The costs were analysed by using Activity Based Cost (ABC) analysis. The budget of the interventional unit was approximately 1.8 million Euro. Material costs accounted for 67%, personnel costs for 17%, equipment costs for 14% and premises costs for 2% of this. The most expensive products were endografting of aortic aneurysms, with a mean price of 5291 Euro and embolizations of cerebral aneurysms (4472 Euro). Endografts formed 87.3% of the total costs in endografting and Guglielmi detachable coils accounted for 63.3% of the total costs in embolizations. The material costs formed the majority of the costs, especially in the newest and most complicated endovascular treatments. Despite the high cost of angiography equipment, its share of the costs is minor. In our experience ABC system is suitable for analysing costs in interventional radiology. (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

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    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. A model-based reconstruction method for 3-D rotational coronary angiography

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    Xie, Lizhe; Hu, Yining; Nunes, Jean-Claude; Bellanger, Jean-Jacques; Bedossa, Marc; Luo, Limin; Toumoulin, Christine

    2010-01-01

    This paper presents a model-based reconstruction method of the coronary tree from a few number of projections in rotational angiography imaging. The reconstruction relies on projections acquired at a same cardiac phase and an energy function minimization that aims to lead the deformation of the 3D model to fit projection data whereas preserving coherence both in time and space. Some preliminary results are provided on simulated rotational angiograms. PMID:21096600

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

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

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    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. PMID:27260483

  15. 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.

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

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    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.

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

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    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.

  18. Evaluation of User Performance in Simulation-Based Diagnostic Cerebral Angiography Training.

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    Zaika, Oleksiy; Nguyen, Ngan; Boulton, Mel; Eagleson, Roy; de Ribaupierre, Sandrine

    2016-01-01

    Simulation of anatomically complex procedures, such as angiography, is becoming more practical, however, computer-based modules require extensive research to assess their effectiveness. We organized two training schemas - alternating cases and consistent cases - and hypothesized that the alternating practice cases would be beneficial to test performance. Eight residents (4 radiology/4 neurosurgery) and 8 anatomy graduate students were trained on the SimbionixTM simulator in order to assess skill acquisition in diagnostic cerebral angiography over 8 sessions. We found that participants improve on total procedure time and total fluoroscopy time (p<0.05), but not on contrast injected or roadmaps created. There were no significant differences between alternating and consistent training types. Additional work needs to be done with higher sample numbers and visuospatial scores as criteria. PMID:27046624

  19. Transient Global Amnesia following Neural and Cardiac Angiography May Be Related to Ischemia

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    Hongzhou Duan

    2016-01-01

    Full Text Available Introduction. Transient global amnesia (TGA following angiography is rare, and the pathogenesis has not been illustrated clearly till now. The aim of this research is to explore the pathogenesis of TGA following angiography by analyzing our data and reviewing the literature. Methods. We retrospectively studied 20836 cases with angiography in our hospital between 2007 and 2015 and found 9 cases with TGA following angiography. The data of these 9 cases were analyzed. Results. We found all 9 cases with TGA following neural angiography (5 in 4360 or cardiac angiography (4 in 8817 and no case with TGA following peripheral angiography (0 in 7659. Statistical difference was found when comparing the neural and cardiac angiography group with peripheral group (p=0.022. Two cases with TGA were confirmed with small acute infarctions in hippocampus after angiography. This might be related to the microemboli which were rushed into vertebral artery following blood flow during neural angiography or cardiac angiography. There was no statistical difference when comparing the different approaches for angiography (p=0.82 and different contrast agents (p=0.619. Conclusion. Based on the positive findings of imaging study and our analysis, we speculate that ischemia in the medial temporal lobe with the involvement of the hippocampus might be an important reason of TGA following angiography.

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

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    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.

  1. A critical approach to gamma variate fit of radionuclide-angiography pulmonary histograms

    International Nuclear Information System (INIS)

    Radionuclide-angiography (RNA) left-to-right intracardiac-shunt quantification algorithms, based on the part-by-part fit technique and the use of a so-called gamma variate model function (GVF), were tested via simulation analysis using data obtained from normal subjects. A good bolus of radioindicator was obtained by administering it directly into the vena subclavia. Normal subjects were defined as those having pulmonary histograms (PH) with no visible distortion caused by a shunt. Pure, non-superimposed data on the downslope of the PH curves, which are lost in presence of a shunt, proved to be appropriate reference values for testing the accuracy of results of standard shunt quantification algorithms. A generalized four-parameter GVF was introduced in order to extend the flexibility of the model function. The use of the three-parametric GVF to reconstruct the downslope of the PH curve out of the upslope data proved to be inadequate. This reveals an evident source of error in algorithms that calculate the shunt contribution by fitting GVF parameters to so-called difference-curve data. It is concluded that the inherent restricted statistical weight of RNA data prevents accurate results being obtained from standard RNA-shunt-assessment algorithms. (orig.)

  2. A prospective randomized comparison of left and right radial approach for percutaneous coronary angiography in Asian populations

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    Hu HY

    2014-06-01

    Full Text Available Hongyu Hu, Qiang Fu, Wei Chen, Dezhao Wang, Xu Hua, Buxing Chen Department of Cardiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People’s Republic of ChinaBackground: The efficacy of coronary angiography may be different in the right radial approach (RRA and the left radial approach (LRA due to more common vascular tortuosity in the RRA. The aim of the study was to determine whether LRA is a valid alternative for coronary angiography compared with RRA in Asian populations. Methods: This is a single-center, prospective, randomized controlled study. A total of 1,400 consecutive patients undergoing diagnostic coronary angiography were recruited and randomized to the RRA (number [n]=700 or LRA (n=700 group. The primary end point was total procedural duration. Secondary end points included fluoroscopy time, dose of radiation including cumulative air kerma and dose area product, contrast volume, and the incidence of vascular complications. Results: Coronary procedural success was achieved in 682 of 700 (97.4% patients in the RRA and 680 of 700 (97.1% in the LRA. The total procedural time (RRA 14.1±6.3 minutes versus LRA 13.2±6.0 minutes; P=0.006 and fluoroscopy time (RRA 3.8±3.3 minutes versus LRA 3.4±2.8 minutes; P=0.046 were significantly shorter via LRA in comparison to RRA. The percentage of hydrophilic wire use was also lower in the LRA group (14% [RRA] versus 10% [LRA]; P=0.016. The dose of radiation and contrast volume were not different between the two approaches. No cases of major bleeding and vascular complications requiring surgical intervention were reported, other than with one patient who experienced a symptomatic stroke and died in the RRA group compared with none in the LRA group. Conclusion: The LRA seems to be a feasible alternative for coronary angiography in Asian patients due to shorter procedural duration and fluoroscopy time, as well as less hydrophilic wire use in comparison to RRA

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

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    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

  4. Carotid stenosis degree in CT angiography: assessment based on luminal area versus luminal diameter measurements

    International Nuclear Information System (INIS)

    The aim of this study was to investigate CT angiography (CTA) luminal area measurements in the assessment of carotid artery stenosis compared with the current clinically used criteria based on lumen diameter measurements. Seventy-two vessels in 36 patients were evaluated by CTA and digital subtraction angiography (DSA). Two observers measured area and diameter stenosis degrees using automated 3D CTA analysis software. The ratio of the largest/smallest luminal diameter at the level of maximal stenosis (L/S ratio) was used to describe lumen morphology. Diagnostic agreement between CTA and DSA was calculated. For the assessment of area stenosis, interobserver and intraobserver correlation coefficients were 0.898 and 0.906 (p<0.001). The correlation coefficient between the diameter stenosis and area stenosis was lower in stenoses with extremely noncircular lumen (L/S ratio ≥1.5) (r=0.797, p<0.001) compared with stenoses with circular lumen (LS ratio <1.2) (r=0.978, p<0.001). Only satisfactory agreement (κ 0.54-0.77, p<0.001) was obtained between area stenosis on CTA and diameter stenosis on DSA. Assessment of stenosis degree with area measurements on 3D CTA proved to be reproducible. Area stenosis provides a less-severe estimate of the degree of carotid stenosis but might theoretically express the real hemodynamic significance of the lesion better than diameter stenosis, especially in stenoses with noncircular lumen. (orig.)

  5. Automated bone removal in CT angiography : Comparison of methods based on single energy and dual energy scans

    NARCIS (Netherlands)

    van Straten, Marcel; Schaap, Michiel; Dijkshoorn, Marcel L.; Greuter, Marcel J.; van der Lugt, Aad; Krestin, Gabriel P.; Niessen, Wiro J.

    2011-01-01

    Purpose: To evaluate dual energy based methods for bone removal in computed tomography angiography (CTA) images and compare these with single energy based methods that use an additional, nonenhanced, CT scan. Methods: Four different bone removal methods were applied to CT scans of an anthropomorphic

  6. 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.)

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

    International Nuclear Information System (INIS)

    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.)

  8. [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.

  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. Fluorescein angiography

    Science.gov (United States)

    ... with cataracts. Alternative Names Retinal photography; Eye angiography Images Retinal dye injection References Maguire JI, Federman JL. Intravenous ... Topics Diabetic Eye Problems Eye ... audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among ...

  11. 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

  12. 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.

  13. 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)

  14. Carotid angiography

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    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

  16. Superselective pseudo-continuous arterial spin labeling angiography

    Energy Technology Data Exchange (ETDEWEB)

    Jensen-Kondering, Ulf [Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel (Germany); Lindner, Thomas, E-mail: thomas.lindner@uksh.de [Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel (Germany); Osch, Matthias J.P. van [C. J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden (Netherlands); Rohr, Axel; Jansen, Olav [Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel (Germany); Helle, Michael [Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel (Germany); Now with Philips GmbH Innovative Technologies, Research Laboratories, Hamburg (Germany)

    2015-09-15

    Highlights: • Superselective arterial spin labeling was capable of acquiring angiograms of individually selected arteries. • Image quality was similar compared with a routinely used time-of-flight angiography. • Superselective arterial spin labeling was utilized in patients with arterio-venous malformations and made it possible to visualize individual feeding vessels in a complete non-invasive way - Abstract: Purpose: To evaluate the utility of a novel non-contrast enhanced, vessel-selective magnetic resonance angiography (MRA) approach based on superselective pseudo-continuous arterial spin labeling (ASL) for the morphologic assessment of intracranial arteries when compared to a clinically used time-of-flight (TOF) MRA. Materials and methods: Three sets of selective ASL angiographies (right and left internal carotid artery, basilar artery) as well as one TOF data set were obtained from each of the five volunteers included in this study on a clinical 1.5T system. The depiction of arterial segments as well as their delineation was evaluated and independently analyzed by two radiologists. Additionally, the ASL angiography approach was performed in two patients suffering from arterio-venous malformations (AVM) in order to illustrate potential applications in a clinical setting. Results: In both angiography techniques, intracranial arteries and their segments (distal branches up to A5 segments of the anterior cerebral arteries, M8 segments of the middle cerebral arteries, and P5 segments of the posterior cerebral arteries) were continuously depicted with excellent inter-reader agreement (κ > 0.81). In AVM patients, reconstructed images of the TOF angiography presented similar information about the size and shape of the AVM as did superselective ASL angiography. In addition, the acquired ASL angiograms of selected vessels allowed assessing the blood supply of individually labeled arteries to the AVM which could also be confirmed by digital subtraction angiography

  17. Digital angiography

    International Nuclear Information System (INIS)

    The basic principles of digital angiography and the clinical applications of the method are discussed. The authors review the experience at the Hotel-Dieu de Montreal covering more than 1000 digital examinations. The indications, results and contra-indications are exposed: numerous advantages (decreased invasiveness, diminished examination times, reduced radiation and improved cost efficiency) far outweigh the disadvantages (slight loss in resolution and small field of examination). A prospective appraisal of the potential and of future developments in digital radiography is also presented

  18. 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

  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. Automated bone removal in CT angiography: Comparison of methods based on single energy and dual energy scans

    Energy Technology Data Exchange (ETDEWEB)

    Straten, Marcel van; Schaap, Michiel; Dijkshoorn, Marcel L.; Greuter, Marcel J.; Lugt, Aad van der; Krestin, Gabriel P.; Niessen, Wiro J. [Department of Radiology, Erasmus MC University Medical Center, P.O. Box 2040, 3000 CA Rotterdam (Netherlands); Departments of Radiology and Medical Informatics, Erasmus MC University Medical Center, P.O. Box 2040, 3000 CA Rotterdam (Netherlands); Department of Radiology, Erasmus MC University Medical Center, P.O. Box 2040, 3000 CA Rotterdam (Netherlands); Department of Radiology, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB Groningen (Netherlands); Department of Radiology, Erasmus MC University Medical Center, P.O. Box 2040, 3000 CA Rotterdam (Netherlands); Departments of Radiology and Medical Informatics, Erasmus MC University Medical Center, P.O. Box 2040, 3000 CA Rotterdam (Netherlands)

    2011-11-15

    Purpose: To evaluate dual energy based methods for bone removal in computed tomography angiography (CTA) images and compare these with single energy based methods that use an additional, nonenhanced, CT scan. Methods: Four different bone removal methods were applied to CT scans of an anthropomorphic thorax phantom, acquired with a second generation dual source CT scanner. The methods differed by the way information on the presence of bone was obtained (either by using an additional, nonenhanced scan or by scanning with two tube voltages at the same time) and by the way the bone was removed from the CTA images (either by masking or subtracting the bone). The phantom contained parts which mimic vessels of various diameters in direct contact with bone. Both a quantitative and qualitative analysis of image quality after bone removal was performed. Image quality was quantified by the contrast-to-noise ratio (CNR) normalized to the square root of the dose (CNRD). At locations where vessels touch bone, the quality of the bone removal and the vessel preservation were visually assessed. The dual energy based methods were assessed with and without the addition of a 0.4 mm tin filter to the high voltage x-ray tube filtration. For each bone removal method, the dose required to obtain a certain CNR after bone removal was compared with the dose of a reference scan with the same CNR but without automated bone removal. The CNRD value of the reference scan was maximized by choosing the lowest tube voltage available. Results: All methods removed the bone completely. CNRD values were higher for the masking based methods than for the subtraction based methods. Single energy based methods had a higher CNRD value than the corresponding dual energy based methods. For the subtraction based dual energy method, tin filtration improved the CNRD value with approximately 50%. For the masking based dual energy method, it was easier to differentiate between iodine and bone when tin filtration

  1. Early surgery of ruptured anterior circulation aneurysm based on multislice helical computerised tomography angiography.

    Science.gov (United States)

    Hui, Ma; Dong, Wang Xiao; Ciceri, E; Marras, C; Tao, Sun; Chun, Xia He; Zheng, Li Zong; Fang, Li Guo

    2007-12-01

    The purpose of this study is to evaluate the utility of three-dimensional computed tomographic angiography (3D-CTA) as the primary diagnostic investigation in patients with spontaneous subarachnoid haemorrhage (SAH) from anterior circulation aneurysms, and to correlate the results with digital subtraction angiography (DSA) and intraoperative findings. From May 2005 to May 2007 a total of 38 consecutive patients admitted for SAH, suspicious for ruptured anterior circulation cerebral aneurysm, underwent 3D-CTA. Inclusion criteria were a SAH confirmed by a non-contrast head computed tomographic scan or by lumbar puncture. Exclusion criteria were: previous DSA, severe contrast medium allergy and severe renal failure. All patients underwent early surgical clipping of the aneurysm. The mean time between SAH onset and surgery was 43.6 h (range, 14-74 h). The 3D-CTA was performed in all cases; and in 13 out of 38 patients (34%) represented the only preoperative exam. In all patients that underwent surgery with the sole 3D-CTA, the images collected allowed a good visualisation of the morphology of aneurysms and of the anatomical relationship with the vascular structures. 3D-CTA allows accurate diagnosis with an excellent visualisation of ruptured aneurysms of the anterior circulation. Our results suggest that, in selected cases, ruptured anterior circulation aneurysms could be successfully treated on the basis of 3D-CTA alone. PMID:18175079

  2. 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.)

  3. MR angiography

    International Nuclear Information System (INIS)

    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)

  4. Therapeutic decision and management of aneurysmal subarachnoid haemorrhage based on computed tomographic angiography.

    Science.gov (United States)

    Dehdashti, A R; Rufenacht, D A; Delavelle, J; Reverdin, A; de Tribolet, N

    2003-02-01

    The purpose of this study was to evaluate the potential of high quality computed tomographic angiography (CTA) to replace digital subtraction angiography (DSA) in cases of ruptured saccular aneurysms and perform early surgical clipping or coiling on the basis of CTA alone. In a prospective study, 100 patients with aneurysmal subarachnoid haemorrhage (SAH) diagnosed by computed tomography underwent CTA. CTA revealed a total of 118 aneurysms including all ruptured aneurysms. A decision of direct surgical clipping, endovascular coiling or therapeutic abstention was made in 89 cases (89%) on the basis of CTA alone. Sixty-one direct surgical procedures were performed after CTA. Twenty-six cases underwent DSA for immediate endovascular treatment of the ruptured aneurysm. In 11 cases (11%), a DSA was performed prior to the therapeutic decision because of unclear aneurysm. Four cases were not treated because of initial poor clinical grade. The surgical findings were compared with CTA data and were considered accurate in all but one case. All patients underwent postoperative DSA within 10 days after SAH. The sensitivity and the specificity of CTA for the detection of all aneurysms, as compared with postoperative DSA, were 95.1 and 100%, respectively. A total of six unruptured aneurysms were missed initially, but were visible retrospectively on CTA in all but one case and were found in patients with multiple aneurysms in whom the ruptured aneurysm was detected by CTA. Current quality CTA allows reliable pretreatment planning for the majority of cases of aneurysmal subarachnoid haemorrhage and diminishes the pretreatment evaluation time critically. Complementary pretreatment DSA is required in situations where CTA characteristics of the ruptured aneurysm is unsatisfactory. PMID:12779201

  5. Evaluation of Intracranial Vasculatures in Healthy Subjects with Arterial-Spin-Labeling-Based 4D-MR Angiography at 3T.

    Science.gov (United States)

    Iryo, Yasuhiko; Hirai, Toshinori; Nakamura, Masanobu; Tateishi, Machiko; Hayashida, Eri; Azuma, Minako; Nishimura, Shinichiro; Kitajima, Mika; Yamashita, Yasuyuki

    2016-07-11

    Contrast inherent inflow-enhanced multi-phase angiography combining multiple-phase flow-alternating inversion-recovery (CINEMA-FAIR) is an arterial-spin-labeling-based four-dimensional magnetic resonance angiography (4D-MRA) technique. Two neuroradiologists independently evaluated the depiction of the intracranial vasculatures in healthy subjects with 3T 4D-MRA using CINEMA-FAIR. Our results indicated that this technique can provide good visualization of the cerebral arteries with a high spatial and temporal resolution. It appears to have sufficient resolution for identifying flow difference in the anterior and posterior circulation in healthy subjects. PMID:26701696

  6. Noise-immune complex correlation for optical coherence angiography based on standard and Jones matrix optical coherence tomography

    Science.gov (United States)

    Makita, Shuichi; Kurokawa, Kazuhiro; Hong, Young-Joo; Miura, Masahiro; Yasuno, Yoshiaki

    2016-01-01

    This paper describes a complex correlation mapping algorithm for optical coherence angiography (cmOCA). The proposed algorithm avoids the signal-to-noise ratio dependence and exhibits low noise in vasculature imaging. The complex correlation coefficient of the signals, rather than that of the measured data are estimated, and two-step averaging is introduced. Algorithms of motion artifact removal based on non perfusing tissue detection using correlation are developed. The algorithms are implemented with Jones-matrix OCT. Simultaneous imaging of pigmented tissue and vasculature is also achieved using degree of polarization uniformity imaging with cmOCA. An application of cmOCA to in vivo posterior human eyes is presented to demonstrate that high-contrast images of patients’ eyes can be obtained. PMID:27446673

  7. Synchrotron-based intra-venous K-edge digital subtraction angiography in a pig model: A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Schueltke, Elisabeth [Departments of Surgery, University of Saskatchewan, Saskatoon, SK (Canada); Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK (Canada); Department of Neurological Sciences, Walton Medical Centre, University of Liverpool, Liverpool L97 LJ (United Kingdom)], E-mail: e.schultke@usask.ca; Fiedler, Stefan [European Molecular Biology Laboratory (EMBL), Nottkestrasse 85, 22603 Hamburg (Germany); Nemoz, Christian [European Synchrotron Radiation Facility (ESRF), 6 rue Horowitz, 38043 Grenoble (France); Ogieglo, Lissa [Departments of Surgery, University of Saskatchewan, Saskatoon, SK (Canada); Kelly, Michael E. [Departments of Surgery, University of Saskatchewan, Saskatoon, SK (Canada); Department of Neurosurgery, Section of Cerebrovascular and Endovascular Neurosurgery, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH (United States); Crawford, Paul [Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herfordshire AL9 7TA (United Kingdom); Esteve, Francois [INSERM U836-ESRF, 6 rue Horowitz, 38043 Grenoble (France); Brochard, Thierry; Renier, Michel; Requardt, Herwig; Le Duc, Geraldine [European Synchrotron Radiation Facility (ESRF), 6 rue Horowitz, 38043 Grenoble (France); Juurlink, Bernhard [Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK (Canada); Meguro, Kotoo [Departments of Surgery, University of Saskatchewan, Saskatoon, SK (Canada)

    2010-03-15

    Background: K-edge digital subtraction angiography (KEDSA) combined with the tunability of synchrotron beam yields an imaging technique that is highly sensitive to low concentrations of contrast agents. Thus, contrast agent can be administered intravenously, obviating the need for insertion of a guided catheter to deliver a bolus of contrast agent close to the target tissue. With the high-resolution detectors used at synchrotron facilities, images can be acquired at high spatial resolution. Thus, the KEDSA appears particularly suited for studies of neurovascular pathology in animal models, where the vascular diameters are significantly smaller than in human patients. Materials and methods: This feasibility study was designed to test the suitability of KEDSA after intravenous injection of iodine-based contrast agent for use in a pig model. Four adult male pigs were used for our experiments. Neurovascular angiographic images were acquired using KEDSA with a solid state Germanium (Ge) detector at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Results: After intravenous injection of 0.9 ml/kg iodinated contrast agent (Xenetix), the peak iodine concentrations in the internal carotid and middle cerebral arteries reached 35 mg/ml. KEDSA images in radiography mode allowed the visualization of intracranial arteries of less than 1.5 mm diameter.

  8. Noise-based tube current reduction method with iterative reconstruction for reduction of radiation exposure in coronary CT angiography

    International Nuclear Information System (INIS)

    Purpose: To investigate the potential of noise-based tube current reduction method with iterative reconstruction to reduce radiation exposure while achieving consistent image quality in coronary CT angiography (CCTA). Materials and methods: 294 patients underwent CCTA on a 64-detector row CT equipped with iterative reconstruction. 102 patients with fixed tube current were assigned to Group 1, which was used to establish noise-based tube current modulation formulas, where tube current was modulated by the noise of test bolus image. 192 patients with noise-based tube current were randomly assigned to Group 2 and Group 3. Filtered back projection was applied for Group 2 and iterative reconstruction for Group 3. Qualitative image quality was assessed with a 5 point score. Image noise, signal intensity, volume CT dose index, and dose-length product were measured. Results: The noise-based tube current modulation formulas were established through regression analysis using image noise measurements in Group 1. Image noise was precisely maintained at the target value of 35.00 HU with small interquartile ranges for Group 2 (34.17–35.08 HU) and Group 3 (34.34–35.03 HU), while it was from 28.41 to 36.49 HU for Group 1. All images in the three groups were acceptable for diagnosis. A relative 14% and 41% reduction in effective dose for Group 2 and Group 3 were observed compared with Group 1. Conclusion: Adequate image quality could be maintained at a desired and consistent noise level with overall 14% dose reduction using noise-based tube current reduction method. The use of iterative reconstruction further achieved approximately 40% reduction in effective dose

  9. 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

  10. 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.

  11. Magnetic resonance angiography

    Science.gov (United States)

    MRA; Angiography - magnetic resonance ... Kwong RY. Cardiovascular Magnetic Resonance Imaging. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine . ...

  12. 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%.

  13. The Activity-Based Approach

    OpenAIRE

    McNally, Michael G.; Rindt, Craig

    2008-01-01

    What is the activity-based approach (ABA) and how does it differ from the conventional trip-based model of travel behavior? From where has the activity approach evolved, what is its current status, and what are its potential applications in transportation forecasting and policy analysis. What have been the contributions of activity-based approaches to understanding travel behavior? The conventional trip-based model of travel demand forecasting (see Chapters 2 and 3) has always lacked...

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. Reconstruction of coronary arteries from X-ray angiography: A review.

    Science.gov (United States)

    Çimen, Serkan; Gooya, Ali; Grass, Michael; Frangi, Alejandro F

    2016-08-01

    Despite continuous progress in X-ray angiography systems, X-ray coronary angiography is fundamentally limited by its 2D representation of moving coronary arterial trees, which can negatively impact assessment of coronary artery disease and guidance of percutaneous coronary intervention. To provide clinicians with 3D/3D+time information of coronary arteries, methods computing reconstructions of coronary arteries from X-ray angiography are required. Because of several aspects (e.g. cardiac and respiratory motion, type of X-ray system), reconstruction from X-ray coronary angiography has led to vast amount of research and it still remains as a challenging and dynamic research area. In this paper, we review the state-of-the-art approaches on reconstruction of high-contrast coronary arteries from X-ray angiography. We mainly focus on the theoretical features in model-based (modelling) and tomographic reconstruction of coronary arteries, and discuss the evaluation strategies. We also discuss the potential role of reconstructions in clinical decision making and interventional guidance, and highlight areas for future research. PMID:27054277

  19. Occupational Exposure in Angiography (Prague Workplaces)

    International Nuclear Information System (INIS)

    The results of measurements, which were performed at angiography departments, are presented. The aim of this work was not only to assess patient exposure but also to perform a survey of the occupational exposures of physicians during common angiography examinations of the skull, chest, abdomen and limbs. Patient data, type of examination, fluoroscopy time, the whole number of film frames, dose-area product (Diameter E) and physician dose (Stephen 6000) were also recorded. There are many factors influencing the level of measured exposures. They include input parameters of X ray performance (kV, mA, projection, diaphragms, ZOOM, type of record etc) and individual approach of the physicians. This paper contributes to the discussion about the increasing exposures of the physicians specialising in diagnostic and interventional angiography. (author)

  20. Gender Based Differences in Risk Factor Profile and Coronary Angiography of Patients Presenting with Acute Myocardial Infarction in North Indian Population

    Science.gov (United States)

    Mahajan, Vijay; Grover, Sumit; Mahajan, Amit; Mahajan, Nipun

    2016-01-01

    Introduction Coronary Artery Disease (CAD) among women presents atypically with atypical chest pain, neck pain, nausea, fatigue and dyspnoea. Co-existing co-morbidities such as Diabetes Mellitus (DM) and hypertension along with difference in risk factor prevalence makes it necessary to have a gender specific approach. Aim To study gender specific differences in diagnosing and treating Acute Myocardial Infarction (AMI) in North Indian population. Materials and Methods Fifty consecutive men and women presenting with AMI were studied. A detailed history including symptoms, history of DM, hypertension, smoking and dyslipidaemia was obtained. ECG, evaluation of cardiac enzymes (CPK-MB, Troponin I), RBS, lipid profile, two dimensional transthoracic echocardiography and coronary angiography were performed. The data was statistically analysed. Results Among 100 patients (50 males and females each), we found a later age at presentation (62 y vs 56.5 y) and higher prevalence of diabetes (52% vs 24%, p=0.004) and hypertension (46% vs 28%) among females but more dyslipidaemia (34% vs 26%), smoking (44% vs 0%, p=0.0) and higher BMI (25.58 vs 23.74, p=0.019) among males. More females presented with atypical symptoms (16% vs 6%) and were detected to have insignificant CAD (14% vs 2%) than males. Conclusion North Indian women with presentation at a later age, with atypical symptoms, more incidences of risk factors such as diabetes and hypertension along with lesser dyslipidaemia and BMI than males need a higher index of suspicion while evaluating them for CAD. Misdiagnosis is more likely because of atypical presentation. A milder disease on angiography and a lower incidence of multiple vessel disease is a common finding. We recommend more and larger Indian studies to acquire more data so that this growing prevalence of CAD in women can be curbed. PMID:27437262

  1. Validity of computational hemodynamics in human arteries based on 3D time-of-flight MR angiography and 2D electrocardiogram gated phase contrast images

    Science.gov (United States)

    Yu, Huidan (Whitney); Chen, Xi; Chen, Rou; Wang, Zhiqiang; Lin, Chen; Kralik, Stephen; Zhao, Ye

    2015-11-01

    In this work, we demonstrate the validity of 4-D patient-specific computational hemodynamics (PSCH) based on 3-D time-of-flight (TOF) MR angiography (MRA) and 2-D electrocardiogram (ECG) gated phase contrast (PC) images. The mesoscale lattice Boltzmann method (LBM) is employed to segment morphological arterial geometry from TOF MRA, to extract velocity profiles from ECG PC images, and to simulate fluid dynamics on a unified GPU accelerated computational platform. Two healthy volunteers are recruited to participate in the study. For each volunteer, a 3-D high resolution TOF MRA image and 10 2-D ECG gated PC images are acquired to provide the morphological geometry and the time-varying flow velocity profiles for necessary inputs of the PSCH. Validation results will be presented through comparisons of LBM vs. 4D Flow Software for flow rates and LBM simulation vs. MRA measurement for blood flow velocity maps. Indiana University Health (IUH) Values Fund.

  2. 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.].

  3. 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.

  4. Reducing radiation dose in 64-row spiral CT coronary angiography: study based on individualized scan dosage protocol

    International Nuclear Information System (INIS)

    Objective: To investigate the methods of reducing radiation dose in CT coronary angiography through optimizing individualized scan dosage protocol. Methods: Two hundred patients (group A) underwent coronary CTA examination which was performed with fixed 120 kV and variable mA according to their BMI. The mA was set as 150-300 mA (BMI < 18.5 kg/m2), 300-500 mA (18.5 kg/m2 ≤ BMI < 25.0 kg/m2), and 500-800 mA (BMI ≥ 25.0 kg/m2). When all examinations were finished, a linear regression was employed to analyze the correlation between mA and BMI, body surface (Suf), image noise (SD) respectively. The results of the analysis were used to formulate a regression equation, which was further used to establish a table list for quick search on how much mA that individualized coronary CTA scan would need. Another 200 patients (group B) enrolled for the individualized scan were scanned under new protocol that previous study established. The tube voltage was 100 and 120 kV. The tube current was variable according to the data in the table list. One-way ANOVA and Kruskal-wallis H test were used for statistics. Results: Regression equation between mA and BMI, Suf, SD was: mA =17.984 × BMI + 169.149 × Suf-2.282 × SD-361.039. The SD (group A: 32.08 ± 5.80, group B: 28.60±4.47), dose index volume (CTDIvol) [group A: (41.97 ± 11.37) mGy, group B: (33.18±10.07) mGy], effective dose(ED) [group A: (10.91 ±3.07) mSy, group B: (8.83 ±2.72)mSv] had significant differences between the two groups (F=43.45, 63.71, 49.07 respectively, P<0.01 for all). The SD and ED results obtained in group B were better than those in group A. Conclusion: Better performances were obtained when BMI combined Suf was used as a new individualized protocol than when BMI was used only, which means good image quality and lower radiation dosage in coronary CTA examination. (authors)

  5. 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.

  6. 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.

  7. Invasive or non invasive angiography? The role of conventional catheder angiography

    International Nuclear Information System (INIS)

    Within the last decade, diagnostic and interventional angiography have been developed to a high degree of performance, due to the widespread use of DSA, the miniaturisation of the puncture trauma and the introduction sets (catheters, sheaths), the development of high-tech materials (e.g., Nitinol guidewires) and the application of non-ionic, low osmolal contrast media. The specific risks of the procedure, thereby, have been significantly reduced, but could not be totally eliminated. To evaluate vascular diseases non-invasively, special attention was attributed to the progress of colour coded duplex, (spiral) CT-angiography and (CE)MR-angiography, based on the estbalished imaging with US, CT and MRT. The matter in question is whether or not they can substitute the role of conventional angiography as the 'gold standard' of vessel imaging. Clinical validity and economic efficiency both determine the indication for the use of invasive or non-invasive methods. In diagnostic procedures, there is a growing tendency for the use of non-invasive techniques, like in imaging of the abdominal and thoracic aorta, the renal, pulmonary and extra- and intra-cranial arteries. Conventional angiography is still reserved for the evaluation of small vessels of the upper and lower extremities, and vessel status in preoperative conditions (carotid, celiac trunk, mesenteric and renal arteries and aneurysms of the cerebral vasculature). Fluoroscopic guiding of catheters and contrast enhancement in interventional procedures, however, cannot be substituted by alternative techniques in the foreseeable future. (orig.)

  8. 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.)

  9. Coronary CT angiography and MR angiography of Kawasaki disease

    International Nuclear Information System (INIS)

    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.)

  10. 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

  11. “Real-world” comparison of non-invasive imaging to conventional catheter angiography in the diagnosis of cerebral aneurysms

    OpenAIRE

    Tomycz, Luke; Bansal, Neil K.; Hawley, Catherine R.; Goddard, Tracy L.; Ayad, Michael J; Mericle, Robert A.

    2011-01-01

    Background: Based on numerous reports citing high sensitivity and specificity of non-invasive imaging [e.g. computed tomography angiography (CTA) or magnetic resonance angiography (MRA)] in the detection of intracranial aneurysms, it has become increasingly difficult to justify the role of conventional angiography [digital subtraction angiography (DSA)] for diagnostic purposes. The current literature, however, largely fails to demonstrate the practical application of these technologies within...

  12. 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.

  13. 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.

  14. 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.)

  15. Evaluation of clinical bradycardiac effect and respiratory adverse effect of β-blocking agents in coronary computed tomography angiography based on theoretical analysis.

    Science.gov (United States)

    Fujito, Kaori; Takayanagi, Risa; Kimura, Koji; Yokoyama, Haruko; Yamada, Yasuhiko

    2016-04-01

    β-blocking agents are used for patients with tachycardia to improve the image quality of coronary computed tomography angiography (CCTA). In this study, we analyzed the clinical bradycardiac effects and the adverse respiratory effects of five β-blocking agents (landiolol, esmolol, propranolol, metoprolol and atenolol) used for CCTA. The changes of the occupancy binding to β1 or β2 receptor of these drugs were calculated based on the receptor occupancy theory. Thereafter, we predicted both the rate of heart rate decline (▲HR) as a clinical effect and the rate of decrease in forced expiratory volume in 1 s (▲FEV1) as an adverse effect, by using the ternary complex model. The results showed that the drugs with ▲HR greater than 10 %, necessary for CCTA, were as follows: landiolol at 13.5 %, propranolol at 11.0 %, and atenolol at 22.6 %. The ▲HR values at the end of CCTA for those three drugs were 0.3, 6.7, and 22.9 %, respectively. It is desirable for the bradycardiac effect to disappear at the end of CCTA. Therefore, landiolol is thought to be a preferable drug. On the other hand, ▲FEV1 at start and end of CCTA for those three drugs was 0.04-2.5, 34.9-40.3, and 6.0-6.1 %, respectively. Our results suggested that landiolol has the most appropriate effect and safety for patients with tachycardia who are undergoing a CCTA procedure. PMID:25510848

  16. Low contrast volume run-off CT angiography with optimized scan time based on double-level test bolus technique – feasibility study

    International Nuclear Information System (INIS)

    Purpose: To verify the technical feasibility of low contrast volume (40 mL) run-off CT angiography (run-off CTA) with the individual scan time optimization based on double-level test bolus technique. Materials and methods: A prospective study of 92 consecutive patients who underwent run-off CTA performed with 40 mL of contrast medium (injection rate of 6 mL/s) and optimized scan times on a second generation of dual-source CT. Individual optimized scan times were calculated from aortopopliteal transit times obtained on the basis of double-level test bolus technique – the single injection of 10 mL test bolus and dynamic acquisitions in two levels (abdominal aorta and popliteal arteries). Intraluminal attenuation (HU) was measured in 6 levels (aorta, iliac, femoral and popliteal arteries, middle and distal lower-legs) and subjective quality (3-point score) was assessed. Relations of image quality, test bolus parameters and arterial circulation involvement were analyzed. Results: High mean attenuation (HU) values (468; 437; 442; 440; 342; 274) and quality score in all monitored levels was achieved. In 91 patients (0.99) the sufficient diagnostic quality (score 1–2) in aorta, iliac and femoral arteries was determined. A total of 6 patients (0.07) were not evaluable in distal lower-legs. Only the weak indirect correlation of image quality and test-bolus parameters was proved in iliac, femoral and popliteal levels (r values: −0.263, −0.298 and −0.254). The statistically significant difference of the test-bolus parameters and image quality was proved in patients with occlusive and aneurysmal disease. Conclusion: We proved the technical feasibility and sufficient quality of run-off CTA with low volume of contrast medium and optimized scan time according to aortopopliteal transit time calculated from double-level test bolus

  17. The Prognostic Value of a Four-Dimensional CT Angiography-Based Collateral Grading Scale for Reperfusion Therapy in Acute Ischemic Stroke Patients

    Science.gov (United States)

    Zhang, Sheng; Chen, Weili; Tang, Huan; Han, Quan; Yan, Shenqiang; Zhang, Xiaocheng; Chen, Qingmeng; Parsons, Mark; Wang, Shaoshi; Lou, Min

    2016-01-01

    Objective Leptomeningeal collaterals, which affects tissue fate, are still challenging to assess. Four-dimensional CT angiography (4D CTA) originated from CT perfusion (CTP) provides the possibility of non-invasive and time-resolved assessment of leptomeningeal collateral flow. We sought to develop a comprehensive rating system to integrate the speed and extent of collateral flow on 4D CTA, and investigate its prognostic value for reperfusion therapy in acute ischemic stroke (AIS) patients. Methods We retrospectively studied 80 patients with M1 ± internal carotid artery (ICA) occlusion who had baseline CTP before intravenous thrombolysis. The velocity and extent of collaterals were evaluated by regional leptomeningeal collateral score on peak phase (rLMC-P) and temporally fused intensity projections (tMIP) (rLMC-M) on 4D CTA, respectively. The cutoffs of rLMC-P and rLMC-M score for predicting good outcome (mRS score ≤ 2) were integrated to develop the collateral grading scale (CGS) (rating from 0–2). Results The CGS score was correlated with 3-months mRS score (non-recanalizers: ρ = -0.495, p = 0.01; recanalizers: ρ = -0.671, p < 0.001). Patients with intermediate or good collaterals (CGS score of 1 and 2) who recanalized were more likely to have good outcome than those without recanalization (p = 0.038, p = 0.018), while there was no significant difference in outcome in patients with poor collaterals (CGS score of 0) stratified by recanalization (p = 0.227). Conclusions Identification of collaterals based on CGS may help to select good responders to reperfusion therapy in patients with large artery occlusion. PMID:27505435

  18. Low contrast volume run-off CT angiography with optimized scan time based on double-level test bolus technique – feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Baxa, Jan, E-mail: baxaj@fnplzen.cz [Department of Imaging Methods, University Hospital and Charles University Medical School in Pilsen (Czech Republic); Vendiš, Tomáš [Department of Imaging Methods, University Hospital and Charles University Medical School in Pilsen (Czech Republic); Moláček, Jiří [Department of Surgery, University Hospital and Charles University Medical School in Pilsen (Czech Republic); Štěpánková, Lucie [Department of Internal Medicine, University Hospital and Charles University Medical School in Pilsen (Czech Republic); Flohr, Thomas; Schmidt, Bernhard; Korporaal, Johannes G. [Siemens Healthcare, Computed Tomography Division, Forchheim (Germany); Ferda, Jiří [Department of Imaging Methods, University Hospital and Charles University Medical School in Pilsen (Czech Republic)

    2014-03-15

    Purpose: To verify the technical feasibility of low contrast volume (40 mL) run-off CT angiography (run-off CTA) with the individual scan time optimization based on double-level test bolus technique. Materials and methods: A prospective study of 92 consecutive patients who underwent run-off CTA performed with 40 mL of contrast medium (injection rate of 6 mL/s) and optimized scan times on a second generation of dual-source CT. Individual optimized scan times were calculated from aortopopliteal transit times obtained on the basis of double-level test bolus technique – the single injection of 10 mL test bolus and dynamic acquisitions in two levels (abdominal aorta and popliteal arteries). Intraluminal attenuation (HU) was measured in 6 levels (aorta, iliac, femoral and popliteal arteries, middle and distal lower-legs) and subjective quality (3-point score) was assessed. Relations of image quality, test bolus parameters and arterial circulation involvement were analyzed. Results: High mean attenuation (HU) values (468; 437; 442; 440; 342; 274) and quality score in all monitored levels was achieved. In 91 patients (0.99) the sufficient diagnostic quality (score 1–2) in aorta, iliac and femoral arteries was determined. A total of 6 patients (0.07) were not evaluable in distal lower-legs. Only the weak indirect correlation of image quality and test-bolus parameters was proved in iliac, femoral and popliteal levels (r values: −0.263, −0.298 and −0.254). The statistically significant difference of the test-bolus parameters and image quality was proved in patients with occlusive and aneurysmal disease. Conclusion: We proved the technical feasibility and sufficient quality of run-off CTA with low volume of contrast medium and optimized scan time according to aortopopliteal transit time calculated from double-level test bolus.

  19. 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…

  20. 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...

  1. 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.)

  2. 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)

  3. Three-dimensional coronary angiography

    Science.gov (United States)

    Suurmond, Rolf; Wink, Onno; Chen, James; Carroll, John

    2005-04-01

    Three-Dimensional Coronary Angiography (3D-CA) is a novel tool that allows clinicians to view and analyze coronary arteries in three-dimensional format. This will help to find accurate length estimates and to find the optimal viewing angles of a lesion based on the three-dimensional vessel orientation. Various advanced algorithms are incorporated in this 3D processing utility including 3D-RA calibration, ECG phase selection, 2D vessel extraction, and 3D vessel modeling into a utility with optimized workflow and ease-of-use features, which is fully integrated in the environment of the x-ray catheterization lab. After the 3D processing, the 3D vessels can be viewed and manipulated interactively inside the operating room. The TrueView map provides a quick overview of gantry angles with optimal visualization of a single or bifurcation lesion. Vessel length measurements can be performed without risk of underestimating a vessel segment due to foreshortening. Vessel cross sectional diameters can also be measured. Unlike traditional, projection-based quantitative coronary analysis, the additional process of catheter calibration is not needed for diameter measurements. Validation studies show a high reproducibility of the measurements, with little user dependency.

  4. Non-contrast-enhanced renal and abdominal MR angiography using velocity-selective inversion preparation.

    Science.gov (United States)

    Shin, Taehoon; Worters, Pauline W; Hu, Bob S; Nishimura, Dwight G

    2013-05-01

    Non-contrast-enhanced MR angiography is a promising alternative to the established contrast-enhanced approach as it reduces patient discomfort and examination costs and avoids the risk of nephrogenic systemic fibrosis. Inflow-sensitive slab-selective inversion recovery imaging has been used with great promise, particularly for abdominal applications, but has limited craniocaudal coverage due to inflow time constraints. In this work, a new non-contrast-enhanced MR angiography method using velocity-selective inversion preparation is developed and applied to renal and abdominal angiography. Based on the excitation k-space formalism and Shinnar-Le-Roux transform, a velocity-selective excitation pulse is designed that inverts stationary tissues and venous blood while preserving inferiorly flowing arterial blood. As the magnetization of the arterial blood in the abdominal aorta and iliac arteries is well preserved during the magnetization preparation, artery visualization over a large abdominal field of view is achievable with an inversion delay time that is chosen for optimal background suppression. Healthy volunteer tests demonstrate that the proposed method significantly increases the extent of visible arteries compared with the slab-selective approach, covering renal arteries through iliac arteries over a craniocaudal field of view of 340 mm. PMID:22711643

  5. Minimizing projection artifacts for accurate presentation of choroidal neovascularization in OCT micro-angiography.

    Science.gov (United States)

    Zhang, Anqi; Zhang, Qinqin; Wang, Ruikang K

    2015-10-01

    Current optical coherence tomography (OCT) based micro-angiography is prone to a projection (or tailing) effect due to the high scattering property of blood within overlying patent vessels, creating artifacts that interfere with the interpretation of retinal angiographic results. In this work, the projection effect in OCT micro-angiography is examined and its causality is explained by strong light scattering and photon propagation within blood. A simple practical approach is then introduced to minimize these artifacts presented in the outer retinal avascular space, especially useful for examining clinical cases with choroidal neovascularization (CNV). Demonstrated through in-vivo human posterior eye imaging of healthy and CNV subjects, the proposed method is shown effective to eliminate the projection artifacts in outer retinal space of OCT micro-angiography, resulting in better visualization of the pathological neovascularization when compared with the current common approaches. In addition, it is also shown that the proposed method is applicable to minimize the projection artifacts appearing in deep retinal layers. PMID:26504660

  6. Cerebral angiography in leptomeningitis and cerebritis

    International Nuclear Information System (INIS)

    This is a report of the cerebral angiographic findings in cases of meningitis and cerebritis. Fifty-nine patients, 38 of whom were under 1 year of age, underwent cerebral angiography by means of femoral catheterization. All the patients had signs of increased intracranial pressure, seizures, focal cerebral signs, positive transillumination of the head, and or abnormal brain scan findings. A few patients who did not respond to systemic antibiotics as was expected were also evaluated by means of cerebral angiography. The following characteristic angiographic findings were observed in 18 cases of active meningitis: (1) A hasy appearance around the arteries (halo formation) between the late arterial and capillary phases. (2) Narrowing of the arteries in the basal cistern. This sometimes extended to the peripheral arteries. (3) Irregular caliber following the narrowing of arteries (in few cases). (4) Circulation time so slow that veins could be seen in the late arterial phase. (5) Halo formation around the anterior chroidal artery and the clear appearance of the choroid plexus in the venous phase (when the infectious process reached the choroid plexus). Cerebritis could be identified on the angiograms by two signs: (1) local swelling of the brain (mainly the temporal lobe) and (2) staining around the veins without any abnormal signs in the arterial phase (laminar staining). In conclusion, angiography is a meaningful test by which to determine the phase of meningitis and cerebritis. These two conditions should be treated based on valid information obtained by means of CSF examinations and neuroradiological tests, especially CT scan and cerebral angiography. (author)

  7. A new experimental carotid siphon aneurysm model in canine based on the MR angiography and rapid prototyping technology

    International Nuclear Information System (INIS)

    Objective: The aim of the experiment is to make an intracranial aneurysm model in canine. Methods: A digital tube was made based on raw magnetic resonance images of the human intracranial carotid artery. Then 6 tubes were made in the 3D rapid prototyping machine and coated with silicone. Finally we isolated the common carotid arteries of 6 canines and made them go through the tubes and anastomosed them end-to-side to get the aneurysm model. Six stents were implanted after one week. Results: Six aneurysm models were successfully made in canines. The parent artery had similar geometry of the human carotid siphon. All the aneurysms and parent arteries were patent in one week's follow-up. One canine died of excessive anesthesia after stenting. Two vascular models kept patent in one month without stenosis. The other 3 had some stenosis on the bends of the vessel. Conclusions: The aneurysm model in the experiment has high flexibility and reliability. The model provides an effective tool for research and testing neurovascular devices. It's also a useful device to train the neuroradiologists and interventional physicians. (authors)

  8. 3D Multislice CT Angiography in Post-Aortic Stent Grafting: A Pictorial Essay

    International Nuclear Information System (INIS)

    Helical CT angiography has been widely used in both pre- and post-aortic stent grafting and it has been confirmed to be the preferred modality when compared to conventional angiography. The recent development of multislice CT (MSCT) has further enhanced the applications of CT angiography for aortic stent grafting. One of the advantages of MSCT angiography over conventional angiography is that the 3D reconstructions, based on the volumetric CT data, provide additional information during follow-up of aortic stent grafting. While endovascular repair has been increasingly used in clinical practice, the use of 3D MSCT imaging in endovascular repair continues to play an important role. In this pictorial essay, we aimed to discuss the diagnostic performance of 3D MSCT angiography in post aortic stent grafting, including the most commonly used surface shaded display, curvilinear reformation, the maximum intensity projection, volume rendering and virtual endoscopy. The advantages and disadvantages of each 3D reconstruction are also explored

  9. A property rights based consolidation approach

    OpenAIRE

    Casajus, André; Labrenz, Helfried

    2014-01-01

    We suggest a full consolidation approach that takes into account the property rights structure whithin the subsidiaries, in particular, the majority requirements on restructurings. Our approach employs a property rights index based on cooperative game theory.

  10. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Science.gov (United States)

    ... produced by: Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ... I’d like to talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA ...

  11. 经左右桡动脉行冠状动脉造影术效果的荟萃分析%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; 杨翠玲; 贺生亮; 陈德; 燕东; 何智余; 姚亚丽

    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 independently,according to inclusive criteria,exclusion criteria and methods of Cochrane Collaboration.Statistical analysis was performed using Review Manager Software (RevMan 5.1).Results Eleven trials with 5 442 patients were included in the systematic review.The results of meta-analysis showed that when compared with RRA,LRA did not increase the failure rate of the procedures (OR =1.04,95% CI 0.80-1.35,P > 0.05) and amount of contrast medium(mean difference =2.39,95% CI-0.30-5.08),P > 0.05).However,LRA was superior to RRA in reducing fluoroscopy time (standardized mean difference =0.15,95% CI0.06-0.24,P < 0.01).In addition,the incidence of severe tortuosity of subclavian artery was significantly lower with LRA (OR=4.65,95%CI 1.98-10.88,P<0.01).Conclusions Based on the current evidence,LRA shares similar safety with RRA for CAG and is superior to RRA in certain respects.LRA can thus be used either as an alternative approach or routine approach for CAG.%目的 评价经左右桡动脉行冠状动脉造影术的效果.方法 计算机检索PubMed、Embase、Web of Science 、Cochrane Library、中国生物医学文献数据库、中文科技期刊全文数据库、万方数据库和中国知网,时间从建库至2013年1月.由2名研究人员独立按照纳入和排除标准以及Cochrane协作网推荐的方法筛选文献、评价质量,并采用Revman 5.1软件进行荟萃分析.结果 共纳入11项研究,包括5 442例患者.荟萃分析显示:与经右桡动脉途径比较,经左桡动脉途径行冠状动脉造影术没有增加手术失败率(OR=1.04,95% CI0.80 ~ 1.35,P>0.05);在对比剂用量方

  12. 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.

  13. Gadolinium-enhanced magnetic resonance angiography of the abdominal vessels

    International Nuclear Information System (INIS)

    Contrast enhanced (CE) magnetic resonance angiography (MRA) provides high resolution angiograms within 20-40 sec. The technique is based on the acquisition of heavily T1-weighted threedimensional (3D) gradient-echo data sets (FISP) with ultrashort echo-(<2 ms) and repetition times (<5 ms) during the arterial phase of an intravenously injected bolus of a T1-shortening agent such as Gd-DTPA. For MR-angiography of abdominal vessels CE-MRA is better suited than 'time-of-flight' (TOF) and phase-contrast (PC) MRA because motional artifacts can be obviated with breath-held acquisitions. We have optimised the technique and evaluated its potential for angiography of the abdominal aorta and its branches as well as the portal vein and its tributaries. Whilst CE-MRA provides reliable diagnostic accuracy in the aorta and the proximal sections of its branches, small peripheral arteries cannot be assessed accurately. The portal vein and its tributaries can often be depicted better with CE-MRA than with conventional angiography but, like conventional angiography, CE-MRA is hampered by slow and reversed flow, conditions under which TOF or 'true FISP' MRA may perform bst. We have also investigated FLASH-echo-planar imaging (EPI) hybrid techniques, a further technical development which due to shorter acquisition times of 12-15 sec. allows semi-dynamic imaging of the arterial and venous phase and provide better vessel contrast due to the use of fat-suppression. (orig.)

  14. Predictors of positive angiography and evaluation of the outcome of transcatheter control of non variceal upper gastrointestinal hemorrhage

    Directory of Open Access Journals (Sweden)

    Mohammad Abusedera

    2016-03-01

    Conclusion: Transcatheter angiography and embolization is safe and effective. Embolization can be done empirically even when angiographically negative is based on endoscopic localization of bleeding source.

  15. 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.

  16. 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.

  17. Optimization of Ecg Gating in Quantitative Femoral Angiography

    International Nuclear Information System (INIS)

    Purpose: To determine which phase of the heart cycle would yield the highest reproducibility in measuring atherosclerosis-related variables such as arterial lumen volume and edge roughness. Material and Methods: 35 patients with hypercholesterolemia underwent select ive femoral angiography, repeated four times at 10-min intervals. The angiographies were performed with Ecg-gated exposures. In angiographies 1 and 2 the delay from R-wave maximum to each exposure was 0.1 s, in angiographies 3 and 4 the delay was 0.1, 0.3, 0.5 or 0.7 s or the exposures were performed 1/s without Ecg gating. Arterial lumen volume and edge roughness were measured in a 20-cm segment of the superficial femoral artery using a computer-based densitometric method. Measurement reproducibility was determined by comparing angiographies 1-2 and angiographies 3-4. Results: When measuring arterial lumen volume and edge roughness of a 20-cm segment of the femoral artery, reproducibility was not dependent on Ecg gating. In measuring single arterial diameters and cross-sectional areas, the reproducibility was better when exposures were made 0.1 s after the R-wave maximum than when using other settings of the Ecg gating device or without Ecg gating. Conclusion: The influence of pulsatile flow upon quantitative measurement in femoral angiograms seems to be the smallest possible in early systole, as can be demonstrated when measuring single diameters and cross-sectional areas. In variables based on integration over longer segments, measurement reproducibility seems to be independent of phase

  18. Optimization of Ecg Gating in Quantitative Femoral Angiography

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, S.; Berglund, I.; Erikson, U. [Univ. Hospital, Uppsala (Sweden). Dept. of Oncology, Radiology and Clinical Immunology; Johansson, J.; Walldius, G. [Karolinska Hospital, Stockholm (Sweden). King Gustav V Research Inst.

    2003-09-01

    Purpose: To determine which phase of the heart cycle would yield the highest reproducibility in measuring atherosclerosis-related variables such as arterial lumen volume and edge roughness. Material and Methods: 35 patients with hypercholesterolemia underwent select ive femoral angiography, repeated four times at 10-min intervals. The angiographies were performed with Ecg-gated exposures. In angiographies 1 and 2 the delay from R-wave maximum to each exposure was 0.1 s, in angiographies 3 and 4 the delay was 0.1, 0.3, 0.5 or 0.7 s or the exposures were performed 1/s without Ecg gating. Arterial lumen volume and edge roughness were measured in a 20-cm segment of the superficial femoral artery using a computer-based densitometric method. Measurement reproducibility was determined by comparing angiographies 1-2 and angiographies 3-4. Results: When measuring arterial lumen volume and edge roughness of a 20-cm segment of the femoral artery, reproducibility was not dependent on Ecg gating. In measuring single arterial diameters and cross-sectional areas, the reproducibility was better when exposures were made 0.1 s after the R-wave maximum than when using other settings of the Ecg gating device or without Ecg gating. Conclusion: The influence of pulsatile flow upon quantitative measurement in femoral angiograms seems to be the smallest possible in early systole, as can be demonstrated when measuring single diameters and cross-sectional areas. In variables based on integration over longer segments, measurement reproducibility seems to be independent of phase.

  19. Pulmonary angiography with lopamidol 370

    International Nuclear Information System (INIS)

    Fifty-one consecutive patients who underwent pulmonary angiography with iopamidol, 370 mg/ml, were studied prospectively. Patients were asked to grade any heat or pain felt on injection, and were observed for coughing. Right atrial and pulmonary artery pressures were obtained before the first and after the final contrast agent injection. Pressure changes were compared with those in a consecutive group of 25 patients who underwent examinations performed with Na-meglumine diatrizoate, 370 mg/ml. Film quality was evaluated for patient motion. Iopamidol generated marked discomfort in only three patients. Pressure changes were largely unremarkable. In no case was there any significant motion artifact secondary to coughing. Iopamidol is a safe, well-tolerated contrast agent for pulmonary angiography. It improves image quality by nearly eliminating coughing

  20. Angiography of the upper extremity

    International Nuclear Information System (INIS)

    This thesis provides a description of the technical and medical aspects of arteriography of the upper extremity and an extensive analysis of the angiographic anatomy and pathology of 750 selective studies performed in more than 500 patients. A short historical review is provided of angiography as a whole and of arteriography of the hand in particular. The method of percutaneous transfemoral catheterization of the arteries of the upper extremity and particularly the arteries of the hand is considered, discussing the problems the angiographer encounters frequently, describing the angiographic complications which may occur and emphasizing the measures to keep them to a minimum. The use of vasodilators in hand angiography is discussed. A short description of the embryological patterns persisting in the arteries of the arm is included in order to understand the congenital variations of the arteries of the upper extremity. The angiographic patterns and clinical aspects of the most common pathological processes involving the arteries of the upper extremities are presented. Special attention is paid to the correlation between angiography and pathology. (Auth.)

  1. 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.

  2. 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.

  3. Perfusion Angiography in Acute Ischemic Stroke.

    Science.gov (United States)

    Scalzo, Fabien; Liebeskind, David S

    2016-01-01

    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 T max, 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. PMID:27446232

  4. Computed tomography imaging and angiography - principles.

    Science.gov (United States)

    Kamalian, Shervin; Lev, Michael H; Gupta, Rajiv

    2016-01-01

    The evaluation of patients with diverse neurologic disorders was forever changed in the summer of 1973, when the first commercial computed tomography (CT) scanners were introduced. Until then, the detection and characterization of intracranial or spinal lesions could only be inferred by limited spatial resolution radioisotope scans, or by the patterns of tissue and vascular displacement on invasive pneumoencaphalography and direct carotid puncture catheter arteriography. Even the earliest-generation CT scanners - which required tens of minutes for the acquisition and reconstruction of low-resolution images (128×128 matrix) - could, based on density, noninvasively distinguish infarct, hemorrhage, and other mass lesions with unprecedented accuracy. Iodinated, intravenous contrast added further sensitivity and specificity in regions of blood-brain barrier breakdown. The advent of rapid multidetector row CT scanning in the early 1990s created renewed enthusiasm for CT, with CT angiography largely replacing direct catheter angiography. More recently, iterative reconstruction postprocessing techniques have made possible high spatial resolution, reduced noise, very low radiation dose CT scanning. The speed, spatial resolution, contrast resolution, and low radiation dose capability of present-day scanners have also facilitated dual-energy imaging which, like magnetic resonance imaging, for the first time, has allowed tissue-specific CT imaging characterization of intracranial pathology. PMID:27432657

  5. [Transnasal endoscopic approaches to the cranial base].

    Science.gov (United States)

    Lysoń, Tomasz; Sieśkiewicz, Andrzej; Rutkowski, Robert; Kochanowicz, Jan; Turek, Grzegorz; Rogowski, Marek; Mariak, Zenon

    2013-01-01

    Recent advances in surgical endoscopy have made it possible to reach nearly the whole cranial base through a transnasal approach. These 'expanded approaches' lead to the frontal sinuses, the cribriform plate and planum sphenoidale, the suprasellar space, the clivus, odontoid and atlas. By pointing the endoscope laterally, the surgeon can explore structures in the coronal plane such as the cavernous sinuses, the pyramid and Meckel cave, the sphenopalatine and subtemporal fossae, and even the middle fossa and the orbit. The authors of this contribution use most of these approaches in their endoscopic skull base surgery. The purpose of this contribution is to review the hitherto established endoscopic approaches to the skull base and to illustrate them with photographs obtained during self-performed procedures and/or cadaver studies. PMID:23487296

  6. Evaluation of angiography performed by radiographers and nurses

    International Nuclear Information System (INIS)

    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)

  7. Mechatronic Design: A Port-Based Approach

    NARCIS (Netherlands)

    Amerongen, van Job

    2007-01-01

    In this paper we consider the integrated design of a mechatronic system. After considering the different design steps it is shown that a port-based approach during all phases of the design supports a true mechatronic design philosophy. Port-based design enables use of consistent models of the system

  8. Computed Tomographic Angiography (CTA) in Vascular Trauma

    OpenAIRE

    M. Tehrai

    2007-01-01

    In the evaluation of trauma patients, computed tomo-graphy and CT angiography (CTA) are powerful non-invasive tools that provide a large amount of informa-tion in so little time that they have virtually replaced plain film radiography and catheter angiography. In our hospital, CTA has replaced catheter angiogra-phy for diagnosing most vascular injuries, resulting from penetrating and blunt trauma to head, neck, thorax, abdomen and extremities. This lecture will cover current imaging protocols...

  9. Patent ductus venosus: diagnosis by MR angiography

    International Nuclear Information System (INIS)

    We report a 15-year-old boy with patent ductus venosus in whom the diagnosis was made by MR angiography. A patent ductus venosus Arantii is a rare form of portosystemic shunt. Only a few cases have been reported in adults and children. The diagnosis is usually made by US and digital subtraction angiography. In our patient, the diagnosis was first made by MR angiography. This demonstrates the excellent diagnostic potential of the method in paediatric patients. (orig.)

  10. Spinal angiography. Anatomy, technique and indications

    International Nuclear Information System (INIS)

    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.)

  11. Clinical experience of ioxaglate in femoral angiography

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, S.; Mine, H.; Iwai, T. (Tokyo Medical and Dental Univ. (Japan). School of Medicine)

    1982-01-01

    Painless femoral angiography could be performed in patients under slight analgesic premedication by using ioxaglate (320 mg I/ml). Slower flow of ioxaglate resulted in longer segments of the arteries being filled by the contrast column than by using iothalamate, which was confirmed by serial whole-limb angiography. The dynamic characteristics of ioxaglate, in addition to marked reduction of pain, fulfilled the requirements for its use as a contrast medium in femoral or peripheral angiography.

  12. 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...

  13. A subgrid based approach for morphodynamic modelling

    Science.gov (United States)

    Volp, N. D.; van Prooijen, B. C.; Pietrzak, J. D.; Stelling, G. S.

    2016-07-01

    To improve the accuracy and the efficiency of morphodynamic simulations, we present a subgrid based approach for a morphodynamic model. This approach is well suited for areas characterized by sub-critical flow, like in estuaries, coastal areas and in low land rivers. This new method uses a different grid resolution to compute the hydrodynamics and the morphodynamics. The hydrodynamic computations are carried out with a subgrid based, two-dimensional, depth-averaged model. This model uses a coarse computational grid in combination with a subgrid. The subgrid contains high resolution bathymetry and roughness information to compute volumes, friction and advection. The morphodynamic computations are carried out entirely on a high resolution grid, the bed grid. It is key to find a link between the information defined on the different grids in order to guaranty the feedback between the hydrodynamics and the morphodynamics. This link is made by using a new physics-based interpolation method. The method interpolates water levels and velocities from the coarse grid to the high resolution bed grid. The morphodynamic solution improves significantly when using the subgrid based method compared to a full coarse grid approach. The Exner equation is discretised with an upwind method based on the direction of the bed celerity. This ensures a stable solution for the Exner equation. By means of three examples, it is shown that the subgrid based approach offers a significant improvement at a minimal computational cost.

  14. Automatic registration using implicit shape representations: applications in intraoperative 3D rotational angiography to preoperative CTA registration

    International Nuclear Information System (INIS)

    A solution for automatic registration of 3D rotational angiography (XA) to CT/MR of the liver. Targeted for use in treatment planning of liver interventions. A shape-based approach to registration is proposed that does not require specification of landmarks nor is it prone to local minima like purely intensity-based registration methods. Through the use of vessel characteristics, accurate registration is possible even in the presence of deformations induced by catheters and respiratory motion. Registration was performed on eight pairs of multiphase CT angiography and 3D rotational digital angiography datasets. Quantitative validation of the registration accuracy using vessel landmarks was performed on these datasets. The validation study showed that the method has a registration error of 9.41±4.13 mm. In addition, the computation time is well below 60 s making it attractive for clinical application. A new method for fully automatic 3DXA to CT/MR image registration was developed and found to be efficient and accurate using clinically realistic datasets. (orig.)

  15. 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.

  16. ECG changes during cerebral angiography

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, K.; Nishimura, Y.; Yoshida, M.; Itoh, K.; Hayashi, N.; Aoki, J.; Nakamura, K.; Imai, M.; Ono, T.; Morikawa, S.

    1984-09-01

    We have analyzed HR changes greater than 20% among 334 patients and 942 cerebral angiographies. A tachycardial effect was seen in 14.9% of patients, while a bradycardial effect was seen in 7.1% including two patients having cardiac standstill (0.5%). These two patients were examined without atropine premedication after subarachnoid hemorrhage. Patients under 19 years of age, unpremedicated with atropine sulfate and suffering from subarachnoid hemorrhage secondary to ruptured aneurysm or arteriovenous malformation showed a significantly high incidence of bradycardia. On the other hand, patients with the neoplastic disease and having an initial sinus bradycardia showed a significantly high incidence of a tachycardial effect.

  17. 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......SSFP sequence, where the signal destruction of the GRE sequence is avoided. However, for intra-arterial injections, the bSSFP sequence results in strong artefacts, and the GRE sequence is preferred. Hyperpolarized MRA presents many challenges and cannot currently compete with conventional contrast enhanced MRA...

  18. CLINICAL ASPECTS OF PATIENT SELECTION FOR CORONARY ANGIOGRAPHY IN NON-ST ELEVATION ACUTE CORONARY SYNDROME

    Directory of Open Access Journals (Sweden)

    K. A. Kireev

    2015-01-01

    Full Text Available Own clinical experience in the selection of patients with non-ST elevation acute coronary syndrome for coronary angiography based on clinical guidelines of the European Society of Cardiology (2011 is presented.

  19. Magnetic resonance angiography: current status and future directions

    OpenAIRE

    François Christopher J; Grist Thomas M; Hartung Michael P

    2011-01-01

    Abstract With recent improvement in hardware and software techniques, magnetic resonance angiography (MRA) has undergone significant changes in technique and approach. The advent of 3.0 T magnets has allowed reduction in exogenous contrast dose without compromising overall image quality. The use of novel intravascular contrast agents substantially increases the image windows and decreases contrast dose. Additionally, the lower risk and cost in non-contrast enhanced (NCE) MRA has sparked renew...

  20. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... produced by: Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ... I’d like to talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA ...

  1. A practice based approach to forest governance

    NARCIS (Netherlands)

    Arts, Bas; Behagel, Jelle; Turnhout, Esther; de Koning, Jessica; van Bommel, Séverine

    2014-01-01

    ‘Forest governance’ refers to new modes of regulation in the forest sector, such as decentralized, community-based and market-oriented policy instruments and management approaches. Its main theoretical basis consists of two mainstream models: rational choice and neo-institutionalism. Since these mod

  2. 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.

  3. 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...

  4. 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.)

  5. Detection, grading and classification of coronary stenoses in computed tomography angiography.

    Science.gov (United States)

    Kelm, B Michael; Mittal, Sushil; Zheng, Yefeng; Tsymbal, Alexey; Bernhardt, Dominik; Vega-Higuera, Fernando; Zhou, S Kevin; Meer, Peter; Comaniciu, Dorin

    2011-01-01

    Recently conducted clinical studies prove the utility of Coronary Computed Tomography Angiography (CCTA) as a viable alternative to invasive angiography for the detection of Coronary Artery Disease (CAD). This has lead to the development of several algorithms for automatic detection and grading of coronary stenoses. However, most of these methods focus on detecting calcified plaques only. A few methods that can also detect and grade non-calcified plaques require substantial user involvement. In this paper, we propose a fast and fully automatic system that is capable of detecting, grading and classifying coronary stenoses in CCTA caused by all types of plaques. We propose a four-step approach including a learning-based centerline verification step and a lumen cross-section estimation step using random regression forests. We show state-of-the-art performance of our method in experiments conducted on a set of 229 CCTA volumes. With an average processing time of 1.8 seconds per case after centerline extraction, our method is significantly faster than competing approaches. PMID:22003680

  6. 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.

  7. 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.)

  8. 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...

  9. 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.

  10. 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

  11. Acoustic Angiography: A New Imaging Modality for Assessing Microvasculature Architecture

    Directory of Open Access Journals (Sweden)

    Ryan C. Gessner

    2013-01-01

    Full Text Available The purpose of this paper is to provide the biomedical imaging community with details of a new high resolution contrast imaging approach referred to as “acoustic angiography.” Through the use of dual-frequency ultrasound transducer technology, images acquired with this approach possess both high resolution and a high contrast-to-tissue ratio, which enables the visualization of microvascular architecture without significant contribution from background tissues. Additionally, volumetric vessel-tissue integration can be visualized by using b-mode overlays acquired with the same probe. We present a brief technical overview of how the images are acquired, followed by several examples of images of both healthy and diseased tissue volumes. 3D images from alternate modalities often used in preclinical imaging, contrast-enhanced micro-CT and photoacoustics, are also included to provide a perspective on how acoustic angiography has qualitatively similar capabilities to these other techniques. These preliminary images provide visually compelling evidence to suggest that acoustic angiography may serve as a powerful new tool in preclinical and future clinical imaging.

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

    International Nuclear Information System (INIS)

    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.

  13. 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...

  14. 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 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....

  15. Evaluating face trustworthiness: a model based approach

    OpenAIRE

    Todorov, Alexander; Baron, Sean G.; Oosterhof, Nikolaas N.

    2008-01-01

    Judgments of trustworthiness from faces determine basic approach/avoidance responses and approximate the valence evaluation of faces that runs across multiple person judgments. Here, based on trustworthiness judgments and using a computer model for face representation, we built a model for representing face trustworthiness (study 1). Using this model, we generated novel faces with an increased range of trustworthiness and used these faces as stimuli in a functional Magnetic Resonance Imaging ...

  16. DRUG VEHICLE BASED APPROACHES OF PENETRATION ENHANCEMENT

    OpenAIRE

    Swaroop R Lahoti; MOHD. HASSAN G DEHGHAN; Dinesh L Dhamecha; AMIT A RATHI; MARIA SAIFEE

    2009-01-01

    Transdermal delivery of drugs through the skin to the systemic circulation provides a convenient route of administration for a variety of clinical indications. For transdermal delivery of drugs, stratum corneum is the main barrier layer for permeation of drug. So to circumvent the stratum corneum and to increase the flux through skin membrane, different approaches of penetration enhancement are used. Many reviews had described regarding the chemical penetration enhancement but vehicle based e...

  17. 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

  18. 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

  19. 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.

  20. Digital subtraction angiography for breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Tsurumi, Kiyohiko; Okuyama, Nobuo

    1987-07-01

    We performed digital subtraction angiography (DSA) on 42 patients with breast diseases to investigate its efficiency. As a result we came to the following conclusions: 1. The sensitivity was well evaluated in intraarterial digital subtraction angiography (IA-DSA) of breast. 2. IA-DSA could diagnose difficult cases like cancer which had undergone augmentation mammoplasty, or like Paget's disease and others. 3. DSA was a safe examination method. 4. The sensitivity of IA-DSA of breast cancer is superior to intravenous digital subtraction angiography (IV-DSA).

  1. 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.

  2. 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.

  3. Multidetector-row CT angiography of hepatic artery: comparison with conventional angiography

    International Nuclear Information System (INIS)

    To determine the usefulness of three-dimensional CT angiography using multidetector-row CT (MD-CT) for delineating the arterial anatomy of the liver. Hepatic arterial three-dimensional CT angiography was performed using MDCT (lightspeed Qx/I; GE medical systems, milwaukee, Wis., U.S.A.) in 45 patients with HCC undergoing conventional angiography for transcatheter hepatic arterial chemoembolization. The scanning parameters during the early arterial phase were 2.5 mm slice thickness, 7.5 mm rotation of table speed, and a pitch of 3. Images were obtained by one radiologist using maximum intensity projection from axial CT images obtained during the early arterial phase. Two radiologists blinded to the findings of conventional angiography independently evaluated the hepatic arterial anatomy and the quality of the images obtained. Compared with conventional angiography, reader A correctly evaluated the hepatic arterial anatomy depicted at three-dimensional CT angiography. Reader B's evaluation was correct in 40 of 45 patients. Interobserver agreement was good (kappa value, 0.73), and both readers assessed the quality of three-dimensional CT angiography as excellent. Three-dimensional CT angiography using MDCT was accurate for delineating the arterial anatomy of the liver, and interobserver agreement was good. The modality may provide, prior to conventional angiography, valuable information regrading a patient's hepatic arterial anatomy

  4. 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.

  5. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Pediatric Ultrasound Video: Angioplasty & vascular stenting Video: Arthrography Radiology and You About this Site RadiologyInfo.org is ... Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot org Hello, I’m Dr. Elliot ...

  6. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... this Site RadiologyInfo.org is produced by: Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) ... Recently posted: Focused Ultrasound for Uterine Fibroids Dementia Video: General Ultrasound Video: Pediatric Nuclear Medicine Radiology and ...

  7. Towards the use of OCT angiography in clinical dermatology

    Science.gov (United States)

    Baran, Utku; Choi, Woo June; Wang, Ruikang K.

    2016-02-01

    Optical coherence tomography (OCT) is a popular imaging technique used in ophthalmology, and on the way to become clinically viable alternative in dermatology due to its capability of acquiring histopathology level images of in vivo tissue, noninvasively. In this study, we demonstrate the capabilities of OCT-based angiography (OMAG) in detecting high-resolution, volumetric structural and microvascular features of in vivo human skin with various conditions using a swept source OCT system that operates on a central wavelength of 1310 nm with an A-line rate of 100 kHz. OMAG images provide detailed in vivo visualization of microvasculature of abnormal human skin conditions from face, chest and belly. Moreover, the progress of wound healing on human skin from arm is monitored during longitudinal wound healing process. The presented results promise the clinical use of OCT angiography in treatment of prevalent cutaneous diseases within human skin, in vivo.

  8. Ultrahigh-speed non-invasive widefield angiography

    Science.gov (United States)

    Blatter, Cedric; Klein, Thomas; Grajciar, Branislav; Schmoll, Tilman; Wieser, Wolfgang; Andre, Raphael; Huber, Robert; Leitgeb, Rainer A.

    2012-07-01

    Retinal and choroidal vascular imaging is an important diagnostic benefit for ocular diseases such as age-related macular degeneration. The current gold standard for vessel visualization is fluorescence angiography. We present a potential non-invasive alternative to image blood vessels based on functional Fourier domain optical coherence tomography (OCT). For OCT to compete with the field of view and resolution of angiography while maintaining motion artifacts to a minimum, ultrahigh-speed imaging has to be introduced. We employ Fourier domain mode locking swept source technology that offers high quality imaging at an A-scan rate of up to 1.68 MHz. We present retinal angiogram over ˜48 deg acquired in a few seconds in a single recording without the need of image stitching. OCT at 1060 nm allows for high penetration in the choroid and efficient separate characterization of the retinal and choroidal vascularization.

  9. 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.

  10. Giant coronary aneurysm caused by Kawasaki disease: consistency between catheter angiography and electrocardiogram gated dual-source computed tomography angiography

    OpenAIRE

    Hwang, Eun-Ha; Ju, Jung-Ki; Cho, Min-Jung; Lee, Ji-Won; Lee, Hyoung-Doo

    2015-01-01

    We present the case of a 5-year-old child with coronary complications due to Kawasaki disease; this patient unintentionally underwent both dual-source computed tomography (DSCT) coronary angiography and invasive coronary angiographic examination in 2 months. This case highlights the strong consistency of the results between DSCT coronary angiography and invasive coronary angiography. Compared to conventional invasive coronary angiography, DSCT coronary angiography offered additional advantage...

  11. 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.)

  12. 灌注造影显微CT三维重建研究骨痂微血管新生%MicroCT based angiography for studying neovascularization of long bone fracture repair in a rat model

    Institute of Scientific and Technical Information of China (English)

    刘洪鹏; 宋祥胜; 周晓中; 顾军; 张戈; 佘昶; 秦岭; 董启榕

    2012-01-01

    Objective To explore microcomputed tomography (MicroCT) based angiography for exhibiting the neovascularization/angiogenesis of a callus on a rat femoral fracture model.Methods After a closed fracture establishment,60 nale SD rats were randomized into2 groups (30 in each group)and killed at the time point of 1,2,3,4 and 8 weeks The callus in experimental group were scanned by MieroCT and 3-D vasculature images were reconstructed.Vessel size distribution,total vessel volume and volume fraction were quantified.The callus in control group were assessed by using immunohistochemisty for observing the expression of vascular endothelial growth factor (VEGF) and VEGF receptor 2 ( VEGFR-2 ).Results MicroCT based angiography provided native 3-D vasculature images to iconicly reveal the states of neovascularization.And the total vessel volume and volume fraction peaked at 3 weeks ( P < 0.05 ):( 196.00 ± 20.33 ) mm3 and ( 6.70 ± 0.74 ) % respectively ; Immunohistochemistry of callus sections showed the expression of VEGF and VEGFR-2 occurred in the early stage of fracture healing and peaked at 2 weeks,the number of positive cells were ( 113.40 ± 9.17 ) and ( 51.80 ± 4.24 ) respectively ( P <0.05).Conclusion MicroCT based angiography atraumaticly provided high-resolution,quantitative,3-dimention,and objective data analysis.MicroCT based angiography is a robust methodology for evaluation of vascular networks in the callus of a small animal.%目的 探讨灌注造影显微CT(MicroCT)扫描三维重建在研究大鼠骨折愈合时骨痂微血管变化的可行性及意义.方法 60只雄性Sprague-Dawley( SD)大鼠,随机分为实验组及对照组(每组30只),制作标准的右侧股骨中段闭合骨折模型,术后1、2、3、4、8周处死大鼠.实验组大鼠行腹主动脉远端血管造影后,使用MicroCT断层扫描标本,并选取同一兴趣区测定血管体积、体积分数和血管平均直径.对照组骨痂通过免疫组织化学染色法测定血

  13. Persistent Trigeminal Artery Variant Detected by Conventional Angiography and Magnetic Resonance Angiography-Incidence and Clinical Significance-

    Science.gov (United States)

    Rhee, Sun Joo; Lee, Chae Heuck; Lee, Ghi Jai

    2007-01-01

    Objective Persistent trigeminal artery variant (PTAV) is an anastomosis between the internal carotid artery (ICA) and the cerebellar artery without any interposing basilar artery segment. We discuss its probable embryological origin and emphasize clinical implications. Methods Retrospectively 1250 conventional cerebral angiograms and 2947 cranial magnetic resonance angiographies (MRAs) were evaluated for the patients with PTAV. Results Five patients (four men and one woman, 23 to 76 years of age, median age 65 years) had a PTAV. Three patients who underwent MRA had a PTAV (3/2947=0.1%). Four of the patients who underwent cerebral angiography had a PTAV (4/1250=0.32%). Two of 143 patients who underwent both conventional angiography and cranial MRA showed PTAV. The PTAV was an incidental finding in all five patients. The PTAV originated from the cavernous segment of the left ICA in four patients and from the cavernous segment of the right ICA in one patient. The terminal branch of the PTAV was the anterior inferior cerebellar artery (AICA) and superior cerebellar artery (SCA) in two patients and the AICA only in the other three patients. Conclusion Neurosurgeons should be aware of possible presence of PTAV. Manipulation of this vessel during a surgical approach to the parasellar region and percutaneous gasserian ganglion procedure may result in hemorrhage or ischemia. PMID:19096587

  14. 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...

  15. Filtered region of interest cone-beam rotational angiography

    International Nuclear Information System (INIS)

    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 the desired

  16. Digital angiography of camel foot

    International Nuclear Information System (INIS)

    In this study, angiography of normal digits of camel has been accomplished, and the vessels of digits and its distribution have been evaluated to be compared with abnormal digits in the future studies. The thoracic and pelvic limb of 16 camels were collected immediately following slaughter. The palmar and plantar arteries were isolated and catheterised by 18-gauge angiocatheter needle; perfused by 40Ð’–50 ml of iodinated compound injected into each vessel. Angiograms were obtained using dorsopalmer, dorsoplanter and latero-medial projections. In the pelvic limb, above the fetlock joint, the deep palmar arch communicates with the median artery via the anastomotic branch, forming the superfcial palmar arch, from which two branches were clear, 1-palmar common digital artery IV that divides into palmar proper digital arteries IV and V, close to the lateral accessory (ffth) digit. 2-Palmar common digital artery III, produces the first branch and continues distally near the middle of the proximal phalanx, it gives off two palmar branches of the proximal phalanx. Vascular distribution of the pelvic limb was similar to thoracic limb, carrying the name of plantar instead of palmar

  17. 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

  18. 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)

  19. Computed tomography angiography in patients with active gastrointestinal bleeding

    Directory of Open Access Journals (Sweden)

    Fatima Regina Silva Reis

    2015-12-01

    Full Text Available Abstract 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.

  20. 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

  1. 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.

  2. ECG biometric identification: A compression based approach.

    Science.gov (United States)

    Bras, Susana; Pinho, Armando J

    2015-08-01

    Using the electrocardiogram signal (ECG) to identify and/or authenticate persons are problems still lacking satisfactory solutions. Yet, ECG possesses characteristics that are unique or difficult to get from other signals used in biometrics: (1) it requires contact and liveliness for acquisition (2) it changes under stress, rendering it potentially useless if acquired under threatening. Our main objective is to present an innovative and robust solution to the above-mentioned problem. To successfully conduct this goal, we rely on information-theoretic data models for data compression and on similarity metrics related to the approximation of the Kolmogorov complexity. The proposed measure allows the comparison of two (or more) ECG segments, without having to follow traditional approaches that require heartbeat segmentation (described as highly influenced by external or internal interferences). As a first approach, the method was able to cluster the data in three groups: identical record, same participant, different participant, by the stratification of the proposed measure with values near 0 for the same participant and closer to 1 for different participants. A leave-one-out strategy was implemented in order to identify the participant in the database based on his/her ECG. A 1NN classifier was implemented, using as distance measure the method proposed in this work. The classifier was able to identify correctly almost all participants, with an accuracy of 99% in the database used. PMID:26737619

  3. Diagnostic value of 64-slice CT angiography in coronary artery disease: A systematic review

    International Nuclear Information System (INIS)

    Purpose: To perform a systematic review of the diagnostic value of 64-multislice CT (MSCT) angiography in the detection of coronary artery disease (CAD) when compared to conventional coronary angiography. Materials and methods: A search of PUBMED and MEDLINE databases for English literature was performed. Only studies with at least 10 patients comparing 64-slice MSCT angiography with conventional coronary angiography in the detection of CAD were included. Diagnostic value of MSCT angiography compared to coronary angiography was compared and analysed at segment-, vessel- and patient-based assessment. Results: Fifteen studies met selection criteria and were included for analysis. Pooled sensitivity, specificity, positive predictive value and negative predictive value as well as 95% confidence interval (CI) were 97% (94 and 99%), 88% (79 and 97%), 94% (91 and 97%), and 95% (90 and 99%) for patient-based assessment; 92% (85 and 99%), 92% (85 and 99%), 78% (66 and 91%) and 98% (96 and 99%) for vessel-based assessment; 90% (85 and 94%), 96% (95 and 97%), 75%(68 and 82%) and 98% (98 and 99%) for segment-based assessment, respectively. No significant difference was found in the diagnostic accuracy of 64-slice CT in the detection of CAD when comparison was performed either among four main coronary arteries, or between proximal and middle or distal segments (p > 0.05). Conclusion: Our results showed that 64-slice CT angiography has a high-diagnostic value in the detection of CAD. Severe coronary artery calcification seems to be the major factor affecting the visualisation and assessment

  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. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. Differential diagnosis of choroidal melanomas and nervi using scanning laser ophthalmoscopical indocyanine green angiography

    DEFF Research Database (Denmark)

    Andersen, Mads V. Nis; Scherfig, Erik; Prause, J.U.

    1995-01-01

    Ophthalmology, choroidal melanoma, choroidal nevus, fluorescein angiography, indocyanine green (ICG), scanning laser ophthalmoscope (SLO), angiography......Ophthalmology, choroidal melanoma, choroidal nevus, fluorescein angiography, indocyanine green (ICG), scanning laser ophthalmoscope (SLO), angiography...

  11. Optical Coherence Tomography Angiography in Mice: Comparison with Confocal Scanning Laser Microscopy and Fluorescein Angiography

    Science.gov (United States)

    Giannakaki-Zimmermann, Helena; Kokona, Despina; Wolf, Sebastian; Ebneter, Andreas; Zinkernagel, Martin S.

    2016-01-01

    Purpose Optical coherence tomography angiography (OCT-A) allows noninvasive visualization of retinal vessels in vivo. OCT-A was used to characterize the vascular network of the mouse retina and was compared with fluorescein angiography (FA) and histology. Methods In the present study, OCT-A based on a Heidelberg Engineering Spectralis system was used to investigate the vascular network in mice. Data was compared with FA and confocal microscopy of flat-mount histology stained with isolectin IB4. For quantitative analysis the National Cancer Institute's AngioTool software was used. Vessel density, the number of vessel junctions, and endpoints were measured and compared between the imaging modalities. Results The configuration of the superficial capillary network was comparable with OCT-A and flat-mount histology in BALBc mice. However, vessel density and the number of vessel junctions per region of interest (P = 0.0161 and P = 0.0015, respectively) in the deep vascular network of BALBc mice measured by OCT-A was significantly higher than with flat-mount histology. In C3A.Cg-Pde6b+Prph2Rd2/J mice, where the deep capillary plexus is absent, analysis of the superficial network provided similar results for all three imaging modalities. Conclusion OCT-A is a helpful imaging tool for noninvasive, in vivo imaging of the vascular plexus in mice. It may offer advantages over FA and confocal microscopy especially for imaging the deep vascular plexus. Translational Relevance The present study shows that OCT-A can be employed for small animal imaging to assess the vascular network and offers advantages over flat-mount histology and FA.

  12. Relative safety of intravenous digital subtraction angiography over other methods of carotid angiography and impact on clinical management of cerebrovascular disease.

    Science.gov (United States)

    Stevens, J M; Barter, S; Kerslake, R; Schneidau, A; Barber, C; Thomas, D J

    1989-09-01

    Data from a multicentre survey based on three London teaching hospitals on the relative safety and clinical utility of intravenous carotid digital subtraction angiography (DSA) over intra-arterial DSA and conventional carotid angiography are presented. The incidence of stroke during intra-arterial DSA was 0.7% (n = 538) and during conventional angiography was 0.8% (n = 780). The incidence of stroke during intravenous DSA was zero (n = 3710). When it constituted the initial investigation, intravenous DSA achieved a 93.8% replacement value over intra-arterial studies as a whole (n = 474) and 89% replacement value for patients having carotid endarterectomy (n = 99). It was also noted that the installation of DSA equipment at one unit coincided with a sixfold increase in the number of carotid angiographic examinations and an almost threefold increase in carotid endarterectomies. PMID:2790421

  13. Ecosystem-based approach to aquaculture management

    Directory of Open Access Journals (Sweden)

    Patrick White

    2008-12-01

    Full Text Available Ecosystems have real thresholds and limits which, when exceeded, can affect major system restructuring. Once thresholds and limits have been exceeded, changes can be irreversible. Diversity is important to ecosystem functioning. The ecosystem approach is a strategy for the integrated management of land, water, and living resources that promotes conservation and sustainable use in an equitable way. The application of the ecosystem approach will help to reach a balance of the three main objectives: conservation, sustainable use, and a fair and equitable sharing of the benefits and use of the natural resources. Aquaculture development needs to be within the carrying capacity of the water resource so that it is sustainable and does not greatly impact the environment. The determination of the carrying capacity needs to be science-based. The planning of development in ecosystems has been done for freshwater ecosystems within the PAMB (Protected Area Management Board framework, but in many cases this does not give the correct significance to the impact of aquaculture on the water resources in the ecosystem. It also needs to be extended to river basins and estuaries, brackishwater areas, and inland bays, and seas. The planning and management of aquaculture needs to be undertaken at the local government unit (LGU level in a coordinated manner by all the LGUs that have a part of the water resource. The co-management of aquaculture, in terms of monitoring of the environment, monitoring of production, and monitoring of licenses, needs to be funded out of license fees and non-compliance fines collected by the LGUs. A number of these management activities need to be undertaken jointly (monitoring the environment and others separately but in a coordinated manner (e.g., checking licenses and checking compliance.

  14. Comparison between fast contrast-enhanced MR angiography and DSA in diagnosing spinal cord vascular malformations

    International Nuclear Information System (INIS)

    Objective: To evaluate the diagnostic and clinical value of fast contrast-enhanced MR angiography (CE-MRA) with elliptic centric phase-encoding in spinal cord vascular malformations. Methods Fast three-dimensional contrast-enhanced MR angiography with elliptic centric phase-encoding and superconducting 1.5T system was applied prospectively in twenty-five consecutive patients with clinically suspected of spinal cord vascular malformations. All cases were performed with selective spinal digital subtraction angiography, including 18 cases treated by surgery and 2 of them with embolization before surgery, MR angiography follow up were undertaken in ten patients after surgery. Comparing fast contrast-enhanced MR angiography with DSA in diagnosing spinal cord vascular malformations included the origin of feeding artery, the feeding artery, the fistula or the nidus, the draining vein, and the vessel image quality based on the gold standard of selective spinal digital subtraction angiography. Results: Surgically proven diseases included spinal arteriovenous malformations(3 cases), spinal cord perimedullary arteriovenous fistulas (5 cases), spinal dural arteriovenous fistulas (8 cases), paravertebral arteriovenous fistulas (1 case), and spontaneous spinal epidural hematomas (2 eases). Comparing with DSA, the accuracy of MR angiography in diagnosing spinal cord vascular malformations; and detecting the origin of the feeding artery, the feeding artery, the shunt or the nidus and the draining vein were 93.8%, 92%, 96.2%, 100% and 100%, respectively. Overall the degree vascular enhencement were judged to be similar(P>0.05), but the vessel continuity of MRA was inferior to DSA (P<0.05). However, 9 cases of MRA showed no abnormal vascular malformation coinciding with those of surgery. Posttreatment MR angiography did not depict any abnormal vessels again. Conclusions: Fast three-dimensional contrast-enhanced MR angiography with elliptic centric phase-encoding may provide

  15. MR angiography: clinical applications in thoracic surgery

    International Nuclear Information System (INIS)

    MR angiography (MRA) is a promising completion of MR imaging in the preoperative assessment of pulmonary and mediastinal tumours. Scan acquisition was done by sequential FLASH 2D angiograms (TR = 30 ms, TE = 10 ms, FA = 30 ), one section per breathhold, section thickness 5 mm with 1 mm overlap between sequential sections. An automated control procedure allowed individual continuation of the examination. Postprocessing by a maximum-intensity-projection algorithm using angiograms of interest (AOI) resulted in 3D reconstructions illustrating vascular anatomy and avoiding superimposition. This technique was evaluated in a prospective study of 15 patients with malignant intrathoracic tumours. The results were validated by conventional angiographic procedures such as pulmonary angiography, digital subtraction angiography or cavography. Complementing spin-echo (SE) imaging, MRA provided diagnostic information about vessel displacement, stenosis and perfusion defects due to space-occupying lesions. Thus, MRA was helpful in planning thoracic surgery. (orig.)

  16. Evaluating face trustworthiness: a model based approach

    Science.gov (United States)

    Baron, Sean G.; Oosterhof, Nikolaas N.

    2008-01-01

    Judgments of trustworthiness from faces determine basic approach/avoidance responses and approximate the valence evaluation of faces that runs across multiple person judgments. Here, based on trustworthiness judgments and using a computer model for face representation, we built a model for representing face trustworthiness (study 1). Using this model, we generated novel faces with an increased range of trustworthiness and used these faces as stimuli in a functional Magnetic Resonance Imaging study (study 2). Although participants did not engage in explicit evaluation of the faces, the amygdala response changed as a function of face trustworthiness. An area in the right amygdala showed a negative linear response—as the untrustworthiness of faces increased so did the amygdala response. Areas in the left and right putamen, the latter area extended into the anterior insula, showed a similar negative linear response. The response in the left amygdala was quadratic—strongest for faces on both extremes of the trustworthiness dimension. The medial prefrontal cortex and precuneus also showed a quadratic response, but their response was strongest to faces in the middle range of the trustworthiness dimension. PMID:19015102

  17. Evaluating face trustworthiness: a model based approach.

    Science.gov (United States)

    Todorov, Alexander; Baron, Sean G; Oosterhof, Nikolaas N

    2008-06-01

    Judgments of trustworthiness from faces determine basic approach/avoidance responses and approximate the valence evaluation of faces that runs across multiple person judgments. Here, based on trustworthiness judgments and using a computer model for face representation, we built a model for representing face trustworthiness (study 1). Using this model, we generated novel faces with an increased range of trustworthiness and used these faces as stimuli in a functional Magnetic Resonance Imaging study (study 2). Although participants did not engage in explicit evaluation of the faces, the amygdala response changed as a function of face trustworthiness. An area in the right amygdala showed a negative linear response-as the untrustworthiness of faces increased so did the amygdala response. Areas in the left and right putamen, the latter area extended into the anterior insula, showed a similar negative linear response. The response in the left amygdala was quadratic--strongest for faces on both extremes of the trustworthiness dimension. The medial prefrontal cortex and precuneus also showed a quadratic response, but their response was strongest to faces in the middle range of the trustworthiness dimension. PMID:19015102

  18. 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.

  19. Digital subtraction angiography of the thoracic aorta

    International Nuclear Information System (INIS)

    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

  20. Fluorescein and Indocyanine Green Angiography for Uveitis

    Science.gov (United States)

    Herbort, Carl P

    2009-01-01

    In recent years enormous progress has been achieved in investigational procedures for uveitis. Imaging is one such example with the advent of new methods such as indocyanine green angiography, ultrasound biomicroscopy and optical coherence tomography to cite only the most important. This tremendous increase in precision and accuracy in the assessment of the level and degree of inflammation and its monitoring comes in parallel with the development of extremely potent and efficacious therapies. In view of these developments, our whole attitude in the appraisal and investigation of the uveitis patient has to be adapted and correctly reoriented integrating the recent developments and this is no different for ocular angiography. PMID:20404985

  1. Fluorescein and indocyanine green angiography for uveitis

    Directory of Open Access Journals (Sweden)

    Herbort Carl

    2009-01-01

    Full Text Available In recent years enormous progress has been achieved in investigational procedures for uveitis. Imaging is one such example with the advent of new methods such as indocyanine green angiography, ultrasound biomicroscopy and optical coherence tomography to cite only the most important. This tremendous increase in precision and accuracy in the assessment of the level and degree of inflammation and its monitoring comes in parallel with the development of extremely potent and efficacious therapies. In view of these developments, our whole attitude in the appraisal and investigation of the uveitis patient has to be adapted and correctly reoriented integrating the recent developments and this is no different for ocular angiography.

  2. 3D-MR cholangio-angiography

    Energy Technology Data Exchange (ETDEWEB)

    Ohkawa, Shinichi [Isehara Kyohdoh Hospital, Kanagawa (Japan); Hiramatsu, Kyoichi

    1995-04-01

    This report introduces a new 3D-MR cholangio-angiography technique using 3D Fast SE MR cholangiography and 3D phase contrast MR angiography for obstructive jaundice. In all eight cases, dilated biliary tracts as well as portal veins were clearly visualized in the same image. This new technique helped to determine the operability and surgical strategy for cases with obstructive jaundice. It also provided anatomical guidance for surgical procedures. This study suggests that this technique may replace the currently used modalities for obstructive jaundice. (author).

  3. Value of computed angiography in children with osteosarcomas

    International Nuclear Information System (INIS)

    The authors analyse the results of 50 computed angiographies made for osteosarcoma and Ewing's sarcoma. Better tolerated than conventional angiography, computed angiography is also more sensitive in preoperative evaluation of effectiveness of neoadjuvant chemotherapy. Automatic substraction, direct measuring of tumor size and vascularization density give to angiographic changes after chemotherapy the most predictive value. After conservative surgery or radiotherapy digital angiography provides most reliable local follow up

  4. [Intra-arterial thrombolysis of a basilar vascular accident during coronary angiography].

    Science.gov (United States)

    Battikh, K; Rihani, R; Lemahieu, J M; Mokahal, M; Houchaymi, Z; Cornaert, P; Dutoit, A

    2001-09-01

    The authors report the case of a 67 year old man with a previous history of aortobifemoral arterial graft who had unstable angina after carotid endarterectomy. Coronary angiography by the right brachial artery was complicated by a cerebrovascular accident with a reactive coma, convulsions and respiratory problems. Selective angiography of the right vertebral artery showed an image of occlusive thrombosis of the basilar artery. In view of the clinical state and angiographic appearances, the authors decided on immediate intra-arterial thrombolysis with Urokinase which dissolved the clot and reestablished flow in the basilar artery, the cerebellar and posterior cerebral arteries. The outcome was favourable with immediate and good recovery of consciousness and hospital discharge on the sixth day without neurological or radiological sequellae. Cerebrovascular accident is a rare and potentially serious complication of left heart catheterisation which requires immediate cerebral angiography to determine the mechanism and propose an appropriate therapeutic approach. PMID:11603067

  5. Cryo-Balloon Catheter Localization Based on a Support-Vector-Machine Approach.

    Science.gov (United States)

    Kurzendorfer, Tanja; Mewes, Philip W; Maier, Andreas; Strobel, Norbert; Brost, Alexander

    2016-08-01

    Cryo-balloon catheters have attracted an increasing amount of interest in the medical community as they can reduce patient risk during left atrial pulmonary vein ablation procedures. As cryo-balloon catheters are not equipped with electrodes, they cannot be localized automatically by electro-anatomical mapping systems. As a consequence, X-ray fluoroscopy has remained an important means for guidance during the procedure. Most recently, image guidance methods for fluoroscopy-based procedures have been proposed, but they provide only limited support for cryo-balloon catheters and require significant user interaction. To improve this situation, we propose a novel method for automatic cryo-balloon catheter detection in fluoroscopic images by detecting the cryo-balloon catheter's built-in X-ray marker. Our approach is based on a blob detection algorithm to find possible X-ray marker candidates. Several of these candidates are then excluded using prior knowledge. For the remaining candidates, several catheter specific features are introduced. They are processed using a machine learning approach to arrive at the final X-ray marker position. Our method was evaluated on 75 biplane fluoroscopy images from 40 patients, from two sites, acquired with a biplane angiography system. The method yielded a success rate of 99.0% in plane A and 90.6% in plane B, respectively. The detection achieved an accuracy of 1.00 mm±0.82 mm in plane A and 1.13 mm±0.24 mm in plane B. The localization in 3-D was associated with an average error of 0.36 mm±0.86 mm. PMID:26978663

  6. Computed tomography angiography of lower extremities in the emergency room for evaluation of patients with gunshot wounds

    Energy Technology Data Exchange (ETDEWEB)

    Adibi, Ali; Plotnik, Adam N.; Mohajer, Kiyarash; Arellano, Cesar; Ruehm, Stefan G. [University of California, Diagnostic Cardiovascular Imaging, Department of Radiological Sciences, Los Angeles, CA (United States); Krishnam, Mayil S.; Dissanayake, Sumudu [University of California, Cardiovascular and Thoracic Imaging, Department of Radiology, Irvine, CA (United States)

    2014-07-15

    To assess the role of CT angiography in the evaluation of patients with lower extremity gunshot wounds in the emergency room. Eighty patients (73 male, 7 female, mean age 26 years) underwent CT angiography for the evaluation of lower extremity gunshot injuries. Imaging was conducted on the basis of standardized protocols utilizing 16-slice and 64-slice multidetector systems and images were qualitatively graded and assessed for various forms of arterial injury. CT angiography findings indicative of arterial injury were observed in 24 patients (30 %) and a total of 43 arterial injuries were noted; the most common form was focal narrowing/spasm (n = 16, 37.2 %); the most common artery involved was the superficial femoral artery (n = 12, 50 %). In qualitative assessment of images based on a 4-point grading system, both readers considered CT angiography diagnostically excellent (grade 4) in most cases. Surgical findings were consistent with CT angiography and follow-up of patients' medical records showed no arterial injuries in patients with normal findings on initial imaging. Our findings demonstrate that CT angiography is an effective imaging modality for evaluation of lower extremity gunshot wounds and could help limit more invasive procedures such as catheter angiography to a select group of patients. (orig.)

  7. 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

  8. 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

  9. Recent advances in diagnostic approaches for sub-arachnoid hemorrhage.

    Science.gov (United States)

    Kumar, Ashish; Kato, Yoko; Hayakawa, Motoharu; Junpei, Oda; Watabe, Takeya; Imizu, Shuei; Oguri, Daikichi; Hirose, Yuichi

    2011-07-01

    Sub-arachnoid hemorrhage (SAH) has been easily one of the most debilitating neurosurgical entities as far as stroke related case mortality and morbidity rates are concerned. To date, it has case fatality rates ranging from 32-67%. Advances in the diagnostic accuracy of the available imaging methods have contributed significantly in reducing morbidity associated with this deadly disease. We currently have computed tomography angiography (CTA), magnetic resonance angiography (MRA) and the digital subtraction angiography (DSA) including three dimensional DSA as the mainstay diagnostic techniques. The non-invasive angiography in the form of CTA and MRA has evolved in the last decade as rapid, easily available, and economical means of diagnosing the cause of SAH. The role of three dimensional computed tomography angiography (3D-CTA) in management of aneurysms has been fairly acknowledged in the past. There have been numerous articles in the literature regarding its potential threat to the conventional "gold standard" DSA. The most recent addition has been the introduction of the fourth dimension to the established 3D-CT angiography (4D-CTA). At many centers, DSA is still treated as the first choice of investigation. Although, CT angiography still has some limitations, it can provide an unmatched multi-directional view of the aneurysmal morphology and its surroundings including relations with the skull base and blood vessels. We study the recent advances in the diagnostic approaches to SAH with special emphasis on 3D-CTA and 4D-CTA as the upcoming technologies. PMID:22347331

  10. Magnetic resonance angiography of intracranial aneurysms: comparison with intra-arterial digital subtraction angiography

    International Nuclear Information System (INIS)

    Magnetic resonance angiography (MRA) with flow rephased gradient-echo sequences is a new non-invasive method for vascular imaging. We compared MRA and intra-arterial digital subtraction angiography in 18 patients with intracranial aneurysms to test whether MRA presently provides an alternative to cerebral angiography for the diagnosis of these anomalies. MRA showed 19 of the 22 aneurysms detected (86.4%). However, problems, especially with turbulent or slow flow, resulted in 6 studies (27.3%) with limited and 2 with questionable demonstration of an aneurysm, and 1 false negative study. At present, MRA is definitely inferior to angiography for the demonstration of intracranial aneurysms, due to its lower resolution and other limitations. (orig.)

  11. Renal Artery Stenting Using CO2 Gas Angiography in Combination with Iodinated Contrast Angiography.

    Science.gov (United States)

    Adachi, Yuya; Endo, Akihiro; Nakashima, Ryuma; Sugamori, Takashi; Takahashi, Nobuyuki; Kinoshita, Yoshihisa; Tanabe, Kazuaki

    2016-01-01

    A 76-year-old woman was hospitalized repeatedly due to unexplained heart failure. On admission, she had hypertensive acute heart failure. Her symptoms disappeared promptly after the initial treatment; however, her systolic blood pressure remained at over 160 mmHg despite her taking three antihypertensive drugs. Closer examination revealed hemodynamically significant right renal artery stenosis and a lack of left kidney function. We performed percutaneous transluminal renal angioplasty using CO2 angiography in combination with iodinated contrast agents. The patient's renal function and blood pressure improved, however, CO2 gas-induced mild ischemic colitis occurred. We discuss the possibility of the use of combined iodinated contrast angiography and CO2 angiography to avoid contrast-induced nephropathy and the complications peculiar to CO2 angiography. PMID:27580543

  12. Computed tomographic angiography in tetralogy of Fallot.

    Science.gov (United States)

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

    2011-10-01

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

  13. Digital subtraction angiography: patient preparation and care.

    Science.gov (United States)

    Hunt, A H

    1987-08-01

    The use of digital subtraction angiography (DSA) is increasing. Nurses must be prepared to provide quality care to patients who have this relatively new method for radiographically studying the blood vessels. A description of DSA and its applications is provided. Patient preparation, assessment, teaching, and management are described. Complications of the procedure and their management are presented. PMID:2958568

  14. Angiography and angiotherapy of gastrointestinal tract bleeding

    International Nuclear Information System (INIS)

    In selected patients with upper and lower gastrointestinal hemorrhage there is an indication for angiography. Vasoconstrictive drugs or embolization materials can be submitted through the catheter to stop the hermorrhage (angiotherapy). 81 patients were diagnosed by this method. Treatment through the angiographic catheter followed the diagnostic procedure in 41 cases. The hemorrhage was controlled in 36 patients. (orig.)

  15. Unexpected Angiography Findings and Effects on Management.

    Science.gov (United States)

    Neill, Matthew; Charles, Hearns W; Gross, Jonathan S; Farquharson, Sean; Deipolyi, Amy R

    2016-01-01

    Despite progress in noninvasive imaging with computed tomography and magnetic resonance imaging, conventional angiography still contributes to the diagnostic workup of oncologic and other diseases. Arteriography can reveal tumors not evident on cross-sectional imaging, in addition to defining aberrant or unexpected arterial supply to targeted lesions. This additional and potentially unanticipated information can alter management decisions during interventional procedures. PMID:27688932

  16. 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.

  17. Minimally invasive surgery of the anterior skull base: transorbital approaches

    Science.gov (United States)

    Gassner, Holger G.; Schwan, Franziska; Schebesch, Karl-Michael

    2016-01-01

    Minimally invasive approaches are becoming increasingly popular to access the anterior skull base. With interdisciplinary cooperation, in particular endonasal endoscopic approaches have seen an impressive expansion of indications over the past decades. The more recently described transorbital approaches represent minimally invasive alternatives with a differing spectrum of access corridors. The purpose of the present paper is to discuss transorbital approaches to the anterior skull base in the light of the current literature. The transorbital approaches allow excellent exposure of areas that are difficult to reach like the anterior and posterior wall of the frontal sinus; working angles may be more favorable and the paranasal sinus system can be preserved while exposing the skull base. Because of their minimal morbidity and the cosmetically excellent results, the transorbital approaches represent an important addition to established endonasal endoscopic and open approaches to the anterior skull base. Their execution requires an interdisciplinary team approach. PMID:27453759

  18. Interventional angiography in the diagnosis of acute lower gastrointestinal bleeding

    International Nuclear Information System (INIS)

    Interventional angiography with the use of indwelling arterial catheters, anticoagulants, vasodilators and fibrinolytic agents, complements conventional angiography in the diagnosis of acute lower gastrointestinal bleeding. These interventional techniques prolong, augment or reactive bleeding and, by enabling better timing of examinations, they increase the diagnostic efficacy of angiography. In the reported series of 63 patients with acute lower gastrointestinal hemorrhage, interventions increased the diagnostic yield of angiography for demonstration of extravasation from 32% to 65% and decreased the percentage of negative angiograms from 27% to 16%. Indications, techniques and risks of interventional angiography in the diagnosis of acute lower gastrointestinal bleeding are discussed. (orig.)

  19. 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.

  20. MR angiography in the diagnosis of tumors in the head and neck

    International Nuclear Information System (INIS)

    40 normal individuals and 153 patients with lesions in the head and neck were examined by conventional imaging methods and by means of MR angiography (1.5 Tesla Magnetome). The problems to be solved concerned the ralationship between tumors and vessels and vascular anomalies and abnormalities at the skull base (56 cases), the facial skeleton (62 cases) and the neck (35 cases). Digital subtraction angiography was performed in 54 patients and the findings corelated with MR angiography. Optimal results were obtained by using a FISP 3D sequence; in this way arterial structures could be rendered reproducibly down to a diameter of 2 mm. The venous system in the head and neck was best shown by a FLASH 2D sequence. Correlation with arterial DSA showed high accuracy of MR angiography (91%) concerning displacement of vessels, the topography and the recognition of vascular occlusions. Our results indicate that MR angiography is a rapid and reliable procedure for evaluating the arterial and venous changes due to tumors in the head and neck region. (orig.)

  1. 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

  2. Hybrid averaging offers high-flow contrast by cost apportionment among imaging time, axial, and lateral resolution in optical coherence tomography angiography.

    Science.gov (United States)

    Li, Peng; Cheng, Yuxuan; Li, Pei; Zhou, Liping; Ding, Zhihua; Ni, Yang; Pan, Cong

    2016-09-01

    The current temporal, wavelength, angular, and spatial averaging approaches trade imaging time and resolution for multiple independent measurements that improve the flow contrast in optical coherence tomography angiography (OCTA). We find that these averaging approaches are equivalent in principle, offering almost the same flow contrast enhancement as the number of averages increases. Based on this finding, we propose a hybrid averaging strategy for contrast enhancement by cost apportionment. We demonstrate that, compared with any individual approach, the hybrid averaging is able to offer a desired flow contrast without severe degradation of imaging time and resolution. Making use of the extended range of a VCSEL-based swept-source OCT, an angular averaging approach by path length encoding is also demonstrated for flow contrast enhancement. PMID:27607943

  3. 冠状动脉造影和血管成形术诊治老年冠心病:经桡动脉与经股动脉途径对比%Comparison on transradial versus transfemoral approach for coronary angiography and angioplasty in the elderlys with coronary heart disease

    Institute of Scientific and Technical Information of China (English)

    李兴升; 陈庆伟; 王志刚; 柯大智; 吴庆

    2011-01-01

    Objective To compare the advantages and disadvantages of transradial and transfemoral approaches in coronary angiography and angioplasty, and to evaluate the curative efficacy and safety of transradial approach for the elderlys with coronary heart disease (CHD). Methods Totally 1637 patients over or equal to 60 years old with diagnosed CHD or suspected CHD were selected and randomly divided into transradial group (n= 909) and transfemoral group (n= 728). The time and success rate of puncture, time of angiography, X-ray exposure time of angiography, success rate of PCI, complications in puncture site, incidence of vagal reflex, average length of stay and major adverse cardiac events (MACE) 3 months after PCI were compared between the two groups. Results The puncture time of transradial group was longer than that of transfemoral group (P<0.05). There were 897 cases (897/909, 98. 68%) with success puncture of radial artery in transradial group and 722 (722/728, 99. 18%) with success puncture of femoral artery in transfemoral group. There was no difference in success rate of puncture, success rate of PCI and MACE 3 months after PCI between the two group (P> 0. 05), while the time of angiography, X-ray exposure time of angiography, complications in puncture site, incidence of vagal reflex and average length of stay in transradial group were all lower than those in transfemoral group (P<0.01). Conclusion Percutaneous radial artery approach is safe and feasible for PCI in the elderlys with CHD, without lying in bed, lower incidence of local complications and trauma, therefore can be used as the routine approach for PCI, especially for the elderlys.%目的 比较经桡动脉和经股动脉途径在冠状动脉造影和血管成形术中的优缺点,评价经桡动脉途径介入治疗老年冠心病的有效性与安全性.方法 60岁及以上冠心病或可疑冠心病患者1637例,按穿刺途径随机分为桡动脉组(n=909)和股动脉组(n=728),比较两

  4. Three-dimensional Gd-DTPA MR angiography of cerebral blood vessels

    International Nuclear Information System (INIS)

    Subtraction angiography based on three-dimensional fast MR imaging techniques using rephasing and dephasing gradient pulses is widely used. Similar angiograms can be obtained with three-dimensional gradient techniques before and after the administration of Gd-DTPA followed by imaging subtraction. As Gd-DTPA does not penetrate the blood-brain barrier, it does not alter brain images. Measurements were carried out in 14 patients with a 1.0-T whole-body imager (Siemens, Magnetom). Gd-DTPA angiography was superior to rephased-dephased angiography because of the higher signal intensity, lower noise due to short echo times, and high contrast for moving spins caused by Gd-DTPA

  5. 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.

  6. 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

  7. 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

  8. Individually adapted, interactive multiplanar reformations vs. semi-automated coronary segmentation and curved planar reformations for stenosis detection in coronary computed tomography angiography

    International Nuclear Information System (INIS)

    Objective: To evaluate, whether semi-automated vessel extraction and curved planar reformations ('automated vessel extraction') increases diagnostic accuracy in the detection of relevant coronary artery lesions compared to manual, interactive multiplanar interpretation ('manual approach'). Materials and methods: 50 coronary CT angiography datasets were evaluated by four independent readers (two experienced, two novice) for the presence of stenoses exceeding 50% diameter reduction. One experienced and one novice reader each used the 'manual approach' for cases 1-25 and 'automated vessel extraction' for cases 26-50, while the other two readers used the complementary method. Results were compared to those of invasive coronary angiography. Results: Using the 'manual approach', 37 of 42 stenoses were correctly detected by experienced as well as novice readers. 14 vs. 17 lesions were false positive (sensitivity 88%, specificity 91% vs. 89%, PPV 73% vs. 69%, NPV 97%, n.s.). Using 'automated vessel extraction', experienced readers detected 35/42 stenoses compared to 31/42 for novice readers. 7 vs. 11 lesions were missed and 17 vs. 15 false-positive lesions reported (sensitivity 83% vs. 74%, specificity 89% vs. 90%, PPV 67%, NPV 95% vs. 93%, n.s.).In patient-based analysis, for novice readers sensitivity was higher using the 'manual approach' (97%, 29/30 pts. vs. 80%, 24/30 pts., p = 0.069). Conclusions: Semi-automated vessel extraction and curved multiplanar reconstructions do not improve the diagnostic accuracy of coronary CT angiography compared to the use of interactive multiplanar reformations. Especially for less experienced readers, the use of automatically rendered curved multiplanar reconstructions alone cannot be recommended.

  9. Nationwide trends in use and timeliness of diagnostic coronary angiography in acute coronary syndromes from 2005 to 2011

    DEFF Research Database (Denmark)

    Hansen, Kim Wadt; Sørensen, Rikke; Madsen, Mette;

    2015-01-01

    a register-based cohort study of all patients admitted to Danish hospitals with incident acute coronary syndrome in 2005-2011. Diagnostic coronary angiography within 60 days of admission was investigated according to distance tertiles (DTs) calculated as range from each patient's home to the nearest invasive.......94 (0.90-0.98) for 2010-2011. Length of hospital stay, time to coronary angiography, and 60-day mortality decreased in all DT. CONCLUSIONS: This nationwide study found significant increases in diagnostic coronary angiography use over time in incident acute coronary syndrome patients with a relatively......AIMS: To examine trends in the use of diagnostic coronary angiography according to distance from home to the nearest invasive heart centre following implementation of fast-track protocols and extensive pre-hospital triaging of acute coronary syndrome patients. METHODS AND RESULTS: We performed...

  10. 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

  11. Game company marketing : Social media based approach

    OpenAIRE

    Jemeljanova, Olga

    2014-01-01

    The purpose of this thesis work was to conduct a research and plan a marketing strategy for a start-up game company in order to increase visibility and the number of company’s customers. The best suitable approach was found and implemented during the study. The project combined both technical and marketing aspects of media. The research was conducted on marketing, social media, and the current state of the game industry in Finland. Moreover, thirty existing game studios were selected for ...

  12. 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.

  13. 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.

  14. Pluig 'n Train - A Component Based Approach

    Directory of Open Access Journals (Sweden)

    Alke Martens

    2010-10-01

    Full Text Available Technology enhanced learning can look back on a comparably long tradition. Surprisingly, the software systems in this field are seldom constructed based on state-of-the art insights in software engineering. Using basic software engineering techniques involves system descriptions on a formal and abstract level, to use patterns for software development, and to implement the system in a re-usable and adaptable way. Our component based framework JaBInT (Java Based Intelligent Tutoring, which is based on a firm software engineering ground, allows for re-usability, adaptability, and flexibility in system development -- and might thus be a basis for teaching and training software used in ubiquitous learning as well.

  15. Evaluation of vascular pathologies with MR angiography

    International Nuclear Information System (INIS)

    The flow sensitivity of MR imaging methods can be used to visualize vascular structures (MR angiography). In this paper the method of flow-enhanced three-dimensional MR angiography will be presented. This technique makes use of the signal enhancement due to inflow of unsaturated spins into the imaging volume in combination with flow-compensated three-dimensional Fourier transform gradient-echo sequences. Projective images are calculated from the measured data by means of a maximum-intensity algorithm. The procedure was optimized for the visualization of the intra-and extracranial vasculature. The purpose of this study was to demonstrate the potential of this MR angiographic procedure to evaluate vascular disease in a clinical situation. Prospective studies in patients with vascular disease including aneurysms, arteriovenous malformations, arterial occlusion, and stenosis are shown in correlation with conventional procedures

  16. 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.

  17. Media approach to gender-based violence

    OpenAIRE

    Mršević Zorica

    2012-01-01

    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 „wh...

  18. CHARACTER RECOGNITION APPROACH BASED ON ONTOLOGY

    OpenAIRE

    Hacene Belhadef; Aicha Eutamene; Mohamed Khireddine Kholadi

    2011-01-01

    In this paper, we present a general description of a new character recognition process based on ontology, semantically annotated by a domain expert. Such process is based essentially on a matching step between two ontologies, the first represents a domain ontology, containing the typographical description of different characters represent an alphabet of a well definite language (Latin for example), the second ontology, describes the document in question in the form of concepts where each conc...

  19. Knowledge Based Company– a Theoretical Approach

    OpenAIRE

    Cuºu Dorinela

    2011-01-01

    In a stable economic environment, the change may be slow, and the organization would have time to react and maintain its competitive advantages. In contrast in a knowledge-based economy, the economic environment changes rapidly and the response is not the best alternative; in order to succeed, the organizations must be proactive, to anticipate, to be directed towards learning and permanently development. The main resource of a knowledge-based company is the knowledge. This company is focused ...

  20. Constructivism theory based learninga total quality approach /

    OpenAIRE

    Al Natsheh, Anas.; Komulainen, Ruey

    2008-01-01

    Constructivism theory is starting to gain substantial momentum in education process as a base for improving the learning environments and enhancing the learning outcomes. As the focus in constructivism theory based learning is shifted toward the learners, and the learners are expected to play an active role in the learning process, the issue of quality and consistency began to surface due to the absence of a clear quality process that can effectively check and control the learning outcomes. T...

  1. 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…

  2. 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…

  3. 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

  4. 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

  5. NEW APPROACH FOR SOFTWARE PROCESSES REUSING BASED ON SOFTWARE ARCHITECTURES

    OpenAIRE

    Aoussat, Fadila; Ahmed-Nacer, Mohamed; Oussalah, Mourad Chabane

    2010-01-01

    International audience; This paper deals with reusing of software process models. Based on the insufficiencies of existing software process reusing approaches (limited reusability of the software process components), we propose a new approach that promotes a large reuse of existing proven software process models even not oriented components. Our approach is based on two steps: we use domain ontology to capitalize the software process knowledge and we handle the inferred knowledge as software ...

  6. Rationales for Place-based Approaches in Scotland

    OpenAIRE

    Bynner, Claire

    2016-01-01

    The aim of this paper is to remove the confusion surrounding what place-based approaches are, the rationales behind their use, the development of this approach to public service reform in Scotland and the future challenges presented by austerity and welfare reform. Key arguments presented in this paper:  The rationales driving the emergence of new place-based approaches at the neighbourhood level include: o The Civic – in the need for higher quality, more responsive services and for co...

  7. Fluorescein and Indocyanine Green Angiography for Uveitis

    OpenAIRE

    Herbort Carl

    2009-01-01

    In recent years enormous progress has been achieved in investigational procedures for uveitis. Imaging is one such example with the advent of new methods such as indocyanine green angiography, ultrasound biomicroscopy and optical coherence tomography to cite only the most important. This tremendous increase in precision and accuracy in the assessment of the level and degree of inflammation and its monitoring comes in parallel with the development of extremely potent and efficacious therapies....

  8. Assessment of percutaneous transluminal coronary angioplasty by quantitative coronary angiography: diameter versus densitometric area measurements

    NARCIS (Netherlands)

    P.W.J.C. Serruys (Patrick); J.H.C. Reiber (Johan); W. Wijns (William); M.J.B.M. van den Brand (Marcel); C.J. Kooijman; H.J. ten Katen (Harald); P.G. Hugenholtz (Paul)

    1984-01-01

    textabstractCineangiograms of 138 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) were analyzed with a computer-based coronary angiography analysis system. The results before and after dilatation are presented. In a first study group (120 patients), the severity of the o

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Environmentally Sustainable Architecture: Material-Based Technological Design Approach

    Directory of Open Access Journals (Sweden)

    Maziar Asefi

    2016-04-01

    Full Text Available This paper investigates material-based design approach in architectural forms where form generating process is informed by the combination of material properties and behavior as well as environmental constraints. It also tries to inform architects of the necessity of shift from formal form finding processes based on values of industrial age toward materiality in form generating processes. It also tries to overlook the current design practices in material-base design approaches to achieve a holistic understanding of the design process and possibilities. Through a comparative literature review, and an examination of current design practices, this paper elaborates on distinct material-based approach to design architectural form.

  15. 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.

  16. 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.

  17. [Evidence-based medicine: an epistemological approach].

    Science.gov (United States)

    Henao, Daniel Eduardo; Jaimes, Fabián Alberto

    2009-03-01

    Evidence-based medicine gathers physician's experience and the best scientific evidence to make medical decisions. This proposal has been widely promulgated by medical opinion leaders. Despite a large literature supporting this practice, a formal discussion has not been established regarding its epistemological consequences in daily medical work. The main proposal of evidence-based medicine consists of choosing the best medical decision according to the best available results from scientific studies. Herein, the goal was to highlight inappropriate application of the scientific method used by physics to clinical science. The inaccuracy resides in describing health and disease in strictly numeric equivalents that can be homogenized on a continuous scale. Finally, the authors consider each diseased human being as a complex system, unique and particular, and that this being is defined by an historical background as well as current actual context. Therefore, evidence-based medicine possesses certain limitations that must be recognized in order to to provide better health care to patients. PMID:19753837

  18. Environmentally Sustainable Architecture: Material-Based Technological Design Approach

    OpenAIRE

    Maziar Asefi; Zahra Afzali

    2016-01-01

    This paper investigates material-based design approach in architectural forms where form generating process is informed by the combination of material properties and behavior as well as environmental constraints. It also tries to inform architects of the necessity of shift from formal form finding processes based on values of industrial age toward materiality in form generating processes. It also tries to overlook the current design practices in material-base design approaches to achieve a ho...

  19. Postmodern Fuzzy System Theory: A Deconstruction Approach Based on Kabbalah

    OpenAIRE

    Gabriel Burstein; Constantin Virgil Negoita; Menachem Kranz

    2014-01-01

    Modern general system theory proposed a holistic integrative approach based on input-state-output dynamics as opposed to the traditional reductionist detail based approach. Information complexity and uncertainty required a fuzzy system theory, based on fuzzy sets and fuzzy logic. While successful in dealing with analysis, synthesis and control of technical engineering systems, general system theory and fuzzy system theory could not fully deal with humanistic and human-like intelligent systems...

  20. Two approaches to synthesis based on the domain theory

    DEFF Research Database (Denmark)

    Hansen, Claus Thorp; Andreasen, Mogens Myrup

    2002-01-01

    functional reasoning within each domain and between the domains seems to be ruled by the function-means law (Hubka´s law). On the basis of the domain theory and the function-means law we present two formal approaches to the synthesis of mechanical artefacts, namely a design-process-oriented approach and an...... artefact-oriented approach. The design-process-oriented synthesis approach can be seen as a basic design step for composite mechanical artefacts. The artefact-oriented approach has been utilised for the development of computer-based design support systems....

  1. Arts-based and creative approaches to dementia care.

    Science.gov (United States)

    McGreevy, Jessica

    2016-02-01

    This article presents a review of arts-based and creative approaches to dementia care as an alternative to antipsychotic medications. While use of antipsychotics may be appropriate for some people, the literature highlights the success of creative approaches and the benefits of their lack of negative side effects associated with antipsychotics. The focus is the use of biographical approaches, music, dance and movement to improve wellbeing, enhance social networks, support inclusive practice and enable participation. Staff must be trained to use these approaches. A case study is presented to demonstrate how creative approaches can be implemented in practice and the outcomes that can be expected when used appropriately. PMID:26938607

  2. 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.

  3. 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

  4. 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.)

  5. 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.)

  6. 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.

  7. Polyphase Order Analysis Based on Convolutional Approach

    Directory of Open Access Journals (Sweden)

    M. Drutarovsky

    1999-06-01

    Full Text Available The condition of rotating machines can be determined by measuring of periodic frequency components in the vibration signal which are directly related to the (typically changing rotational speed. Classical spectrum analysis with a constant sampling frequency is not an appropriate analysis method because of spectral smearing. Spectral analysis of vibration signal sampled synchronously with the angle of rotation, known as order analysis, suppress spectral smearing even with variable rotational speed. The paper presents optimised algorithm for polyphase order analysis based on non power of two DFT algorithm efficiently implemented by chirp FFT algorithm. Proposed algorithm decreases complexity of digital resampling algorithm, which is the most complex part of complete spectral order algorithm.

  8. 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.

  9. Case-based approaches for knowledge application and organisational learning

    DEFF Research Database (Denmark)

    Wang, Chengbo; Johansen, John; Luxhøj, James T.;

    2005-01-01

    structured processes to execute the organisational learning and knowledge application, which intend to guide the practitioners during the process of manufacturing competence development and improvement. They are based on Case-Based Reasoning (CBR) methodology and rely on cases as the primary knowledge supply....... These practices and activity patterns are based on learning and applying the knowledge internal and external to an organisation. To ensure their smooth formulation process, there are two important techniques designed – an expert adaptation approach and an expert evaluation approach. These two approaches provide...

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

    International Nuclear Information System (INIS)

    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

  11. 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

  12. Dynamic indocyanine green angiography measurements

    Science.gov (United States)

    Holmes, Timothy; Invernizzi, Alessandro; Larkin, Sean; Staurenghi, Giovanni

    2012-11-01

    Dynamic indocyanine green imaging uses a scanning laser ophthalmoscope and a fluorescent dye to produce movies of the dye-filling pattern in the retina and choroid of the eye. It is used for evaluating choroidal neovascularization. Movies are examined to identify the anatomy of the pathology for planning treatment and to evaluate progression or response to treatment. The popularity of this approach is affected by the complexity and difficulty in interpreting the movies. Software algorithms were developed to produce images from the movies that are easy to interpret. A mathematical model is formulated of the flow dynamics, and a fitting algorithm is designed that solves for the flow parameters. The images provide information about flow and perfusion, including regions of change between examinations. Imaged measures include the dye fill-time, temporal dispersion, and magnitude of the dye dilution temporal curves associated with image pixels. Cases show how the software can help to identify clinically relevant anatomy such as feeder vessels, drain vessels, capillary networks, and normal choroidal draining vessels. As a potential tool for research into the character of neovascular conditions and treatments, it reveals the flow dynamics and character of the lesion. Future varieties of this methodology may be used for evaluating the success of engineered tissue transplants, surgical flaps, reconstructive surgery, breast surgery, and many other surgical applications where flow, perfusion, and vascularity of tissue are important.

  13. [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.

  14. 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.

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

    Science.gov (United States)

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

    2015-11-01

    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 research. 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 and complex differential Angio-OCT signals are derived. The theories are validated through the flow phantom and live animal experiments. Using the model developed, 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.

  16. 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",

  17. Poverty reduction Approaches in Kenya: Assessing the Usefulness of the Right Based Approach in Kenya

    Directory of Open Access Journals (Sweden)

    Wambua Leonard Munyao, Ph.D

    2013-06-01

    Full Text Available While billions of dollars have been spent in development projects in least developed countries, poverty continues to increase. This study proposes human-rights based approach to poverty eradication. To this end, the study seeks to assess the key determinants of use of rights- based approaches to poverty reduction and it’s usefulness in Kenya with special reference to NGOs in Kibera. The study further high lights some of the basic skills of implementing the rights based approach to poverty reduction. The attempts to establish the proportion of NGOs applying rights based approach to poverty reduction in Kibera Division as well. The review of relevant literature has been undertaken and a field study done. The study is informed by a qualitative human rights framework.

  18. A model-based approach to service creation

    NARCIS (Netherlands)

    Quartel, Dick A.C.; Sinderen, van Marten J.; Ferreira Pires, Luis

    1999-01-01

    This paper presents a model-based approach to support service creation. In this approach, services are assumed to be created from (available) software components. The creation process may involve multiple design steps in which the requested service is repeatedly decomposed into more detailed functio

  19. Airframe integrity based on Bayesian approach

    Science.gov (United States)

    Hurtado Cahuao, Jose Luis

    Aircraft aging has become an immense challenge in terms of ensuring the safety of the fleet while controlling life cycle costs. One of the major concerns in aircraft structures is the development of fatigue cracks in the fastener holes. A probabilistic-based method has been proposed to manage this problem. In this research, the Bayes' theorem is used to assess airframe integrity by updating generic data with airframe inspection data while such data are compiled. This research discusses the methodology developed for assessment of loss of airframe integrity due to fatigue cracking in the fastener holes of an aging platform. The methodology requires a probability density function (pdf) at the end of SAFE life. Subsequently, a crack growth regime begins. As the Bayesian analysis requires information of a prior initial crack size pdf, such a pdf is assumed and verified to be lognormally distributed. The prior distribution of crack size as cracks grow is modeled through a combined Inverse Power Law (IPL) model and lognormal relationships. The first set of inspections is used as the evidence for updating the crack size distribution at the various stages of aircraft life. Moreover, the materials used in the structural part of the aircrafts have variations in their properties due to their calibration errors and machine alignment. A Matlab routine (PCGROW) is developed to calculate the crack distribution growth through three different crack growth models. As the first step, the material properties and the initial crack size are sampled. A standard Monte Carlo simulation is employed for this sampling process. At the corresponding aircraft age, the crack observed during the inspections, is used to update the crack size distribution and proceed in time. After the updating, it is possible to estimate the probability of structural failure as a function of flight hours for a given aircraft in the future. The results show very accurate and useful values related to the reliability

  20. 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.

  1. Vertebral angiography of cerebellar astrocytoma. Tumor stain, tumor circulation, CT and angiography in diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Kitaoka, K.; Ito, T.; Tashiro, K.; Abe, H.; Tsuru, M.; Miyasaka, K. (Hokkaido Univ., Sapporo (Japan). School of Medicine)

    1982-05-01

    Thirteen cases of cerebellar astrocytoma were examined primarily for tumor stain and pathological tumor circulation by angiography and CT. Tumor stain was observed in only one case by cerebral angiogram. A tumor was demonstrated as an avascular mass in the remaining 12 cases. It is suggested that mural nodules of cystic lesions should have certain weight and sizes so that they could be demonstrated as tumor stain. In the supratentorial region, five of the 12 low-grade astrocytoma exhibited abnormal tumor stain and tumor circulation by cerebral angiogram. It is considered that supratentorial and posterior fossa astrocytoma must usually exhibit different pathological tumor circulation by cerebral angiogram, since each group has distinctive clinical and biological characteristics. CT was performed in 7 of 13 cases. It appeared to be more useful than cerebral angiography in the morphological diagnosis. Especially in cystic tumors, CT produced minute information concerning peritumoral edema, enhancement of margin of cystic astrocytoma after intravenous contrast medium, and marginal enhancement with layering in the dependent part of the cyst. Neuroradiological differential diagnosis of cerebellar astrocytoma and cerebellar hemagioblastoma by CT was difficult in the cases of tumors. However, both tumors were differentiated from each other with ease by tumor stain and tumor circulation in cerebral angiography. Thus, it is concluded that cerebral angiography is superior to CT in differential diagnosis between cerebellar astrocytoma and cerebellar hemangioblastoma.

  2. A Hierarchical Clustering Based Approach in Aspect Mining

    OpenAIRE

    Gabriela Czibula; Grigoreta Sofia Cojocar

    2012-01-01

    A Hierarchical Clustering Based Approach in Aspect Mining Clustering is a division of data into groups of similar objects. Aspect mining is a process that tries to identify crosscutting concerns in existing software systems. The goal is to refactor the existing systems to use aspect oriented programming, in order to make them easier to maintain and to evolve. The aim of this paper is to present a new hierarchical clustering based approach in aspect mining. For this purpose we propose HAC algo...

  3. Binaural HRTF Based Spatialisation: New Approaches and Implementation

    OpenAIRE

    Carty, Brian; Lazzarini, Victor

    2009-01-01

    New approaches to Head Related Transfer Function (HRTF) based artificial spatialisation of audio are presented and discussed in this paper. A brief summary of the topic of audio spatialisation and HRTF interpolation is offered, followed by an appraisal of the existing minimum phase HRTF interpolation method. Novel alternatives are then suggested which essentially approach the problem of phase interpolation more directly. The first technique, based on magnitude interpolati...

  4. Vision Based Fuzzy Control Approaches for Unmanned Aerial Vehicles

    OpenAIRE

    Olivares Mendez, Miguel Angel; Campoy, Pascual

    2015-01-01

    This paper proposed the use of vision based Fuzzy control approaches for autonomous navigation tasks with Unmanned Aerial Vehicles (UAVs). It is shown the advantages of using RGB cameras as the sensor onboard UAVs and the advantages of using Fuzzy logic controllers. It is explained how to set a vision based system and how to define a Fuzzy controller for a general control approach. A specific software was design and used to develop and tune general Fuzzy control app...

  5. A testability transformation approach for state-based programs

    OpenAIRE

    Kalaji, AS; Hierons, RM; Swift, S

    2009-01-01

    Search based testing approaches are efficient in test data generation; however they are likely to perform poorly when applied to programs with state variables. The problem arises when the target function includes guards that reference some of the program state variables whose values depend on previous function calls. Thus, merely considering the target function to derive test data is not sufficient. This paper introduces a testability transformation approach based on the analysis of contro...

  6. A scenario based approach for flexible resource loading under uncertainty

    OpenAIRE

    Wullink, G; Gademann, A.J.R.M.; Hans, E.W.; Harten, van, W.H.

    2003-01-01

    Order acceptance decisions in manufacture-to-order environments are often made based on incomplete or uncertain information. To promise reliable due dates and to manage resource capacity adequately, resource capacity loading is an indispensable supporting tool. We propose a scenario based approach for resource loading under uncertainty that minimises the expected costs. The approach uses an MILP to find a plan that has minimum expected costs over all relevant scenarios. We propose an exact an...

  7. Usefulness of CT angiography for demonstrating cerebral aneurysm

    International Nuclear Information System (INIS)

    We report the usefulness of computed cerebral angiotomography (CT angiography) for demonstrating cerebral aneurysm and the clinical significance of CT angiography for ruptured cerebral aneurysm. Our modified method of CT angiography was easy and less time-consuming. Fifteen seconds after starting a single bolus injection, 1 ml/kg/25 seconds via cubital vein, of contrast medium (60 % urograffin), 5 serial 5 mm thick-CT slices were scanned in every 6.5 seconds including 2 seconds of interval, beginning from an axial level 20 mm above the orbitomeatal line and ending at a level 40 mm. A total of 103 patients were examined in this report, consisting of 70 unruptured asymptomatic, 8 unruptured symptomatic (oculomotor nerve palsy) and 25 subarachnoid hemorrhage (SAH). Seven unruptured aneurysms in 4 asymptomatic cases, 2 unruptured aneurysms in 2 symptomatic cases 27 aneurysms in 24 SAH cases were suspected by CT angiography. Of these 36 aneurysms suspected by CT angiography 32 aneurysms were confirmed by cerebral angiography. The detection rate of CT angiography in this report was 89 %, higher than those of previous reports. Thirteen aneurysms were located at internal carotidposterior communicating artery (ICPC) junction. 11 at anterior communicating artery (Acom), 7 at middle cerebral artery (MCA). CT angiography showed a false positive findings in 4 cases, which were all located at Acom. Four aneurysms were not detected in CT angiography, which were all located at MCA and were very small (2 - 3 mm) in diameter. There were no deteriorated cases during and after CT angiography. We suggest that CT angiography is a useful and safe method for predicting the location of not only unruptured but ruptured aneurysms. (author)

  8. Diagnostic angiography of the cerebrospinal vasculature.

    Science.gov (United States)

    Rabinov, James D; Leslie-Mazwi, Thabele M; Hirsch, Joshua A

    2016-01-01

    Diagnostic catheter angiography remains the gold standard for evaluation of vascular lesions of the brain, head and neck, and spine. It is often combined with cross-sectional and functional imaging to provide a complete anatomic and physiologic workup of patients. Such data are combined with clinical information to help make treatment decisions. This chapter describes the specific techniques for arterial access and catheter navigation of the cerebrospinal vasculature. Discussion of patient positioning, injection rates, and basic anatomy of arterial and venous systems is included. Finally, important safety issues related to contrast allergy, renal failure, and complications are considered. PMID:27432664

  9. 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.)

  10. 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.

  11. EVALUATING PHOTOGRAMMETRIC APPROACH OF IMAGE-BASED POSITIONING

    OpenAIRE

    Li, X; Wang, J.

    2012-01-01

    In recent years, researches in the domain of location-based services have increasingly focused on developing and utilizing alternative positioning techniques for in GPS-denied environment. Image based positioning technique holds good promise for such applications. In this paper, a previously proposed image-based positioning system using photogrammetric methods has been put into rigorous evaluation. The precision and accuracy of such photogrammetric approach of image-based positioning is depen...

  12. [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.

  13. 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.

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

    International Nuclear Information System (INIS)

    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

  16. Coronary computed tomography angiography indicates complexity of percutaneous coronary interventions

    OpenAIRE

    Stähli, B E; Bonassin, F; Goetti, R; Küest, S M; Frank, M.; Altwegg, L A; Gebhard, C; Levis, A; Wischnewsky, M. B.; Lüscher, T F; Alkadhi, H.; Kaufmann, P A; Maier, W.

    2012-01-01

    BACKGROUND: Coronary computed tomography angiography (CCTA) provides information regarding lesion morphology and three-dimensional coronary anatomy incremental to coronary angiography. We addressed the question whether preprocedural CCTA bears potential for guiding percutaneous coronary interventions (PCI). METHODS AND RESULTS: Sixty-six coronary lesions attempted with PCI within 6 months of preprocedural CCTA were retrospectively assessed. Lesion parameters from unenhanced computed tomogr...

  17. On the ultimate x-ray detector for angiography

    NARCIS (Netherlands)

    Slump, C.H.; Kauffman, J.A.; Flynn, M.J.

    2005-01-01

    The purpose of our research is to describe the ultimate X-ray detector for angiography. Angiography is a well established X-ray imaging technique for the examination of blood vessels. Contrast agent is injected followed by X-ray exposures and possible obstructions in the blood vessels can be visuali

  18. Lateral rectus palsy following coronary angiography and percutaneous coronary intervention

    Science.gov (United States)

    Nicholson, Luke; Jones, Ruth; Hughes, David S

    2014-01-01

    We present a rare case of unilateral lateral rectus palsy following an elective coronary angiography and percutaneous coronary intervention in a 78-year-oldwoman. Ophthalmoplegia following coronary angiography is extremely rare and this is the first case of a unilateral lateral rectus palsy following the procedure. PMID:24536054

  19. Computerized tomography and angiography - competing processes in liver diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Wunschik, F.; Luetgemeier, J.; Hoerst, M.

    1981-02-01

    In the diagnostics of liver diseases, computerized tomography is a valuable method. It is particularly superior to angiography in detecting cysts, parasitosis and abscesses. Angiography however is better for known solid tumours regarding differencial diagnosis. Both methods supplement each other in the tumour and bile ducts diagnostics.

  20. 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.

  1. 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...

  2. 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...

  3. 64-multislice detector computed tomography coronary angiography as potential alternative to conventional coronary angiography: a systematic review and meta-analysis

    DEFF Research Database (Denmark)

    Abdulla, Jawdat; Abildstrøm, Steen Zabell; Gøtzsche, Ole;

    2007-01-01

    AIMS: To evaluate the diagnostic accuracy of 64-slice multi-detector computed tomography coronary angiography (64-SCTA) compared with the standard reference conventional coronary angiography (CCA). METHODS AND RESULTS: Based on a systematic search, 27 studies including 1740 patients were eligible...... coronary artery stenosis in per-segment (19 studies) and per-patients (13 studies) populations were 19 and 57.5% respectively. Accuracy tests with 95% confidence intervals comparing 64-SCTA vs. CCA showed that sensitivity, specificity, positive predictive and negative predictive values for native coronary......% by overall per-segment analysis. CONCLUSION: The high diagnostic accuracy of 64-SCTA validates this non-invasive technique as a potential alternative to CCA in carefully selected populations suspected for coronary stenosis....

  4. Carbon Dioxide Angiography: Scientific Principles and Practice.

    Science.gov (United States)

    Cho, Kyung Jae

    2015-09-01

    Carbon dioxide (CO2) is a colorless, odorless gas which occurs naturally in the atmosphere and human body. With the advent of digital subtraction angiography, the gas has been used as a safe and useful alternative contrast agent in both arteriography and venography. Because of its lack of renal toxicity and allergic potential, CO2 is a preferred contrast agent in patients with renal failure or contrast allergy, and particularly in patients who require large volumes of contrast medium for complex endovascular procedures. Understanding of the unique physical properties of CO2 (high solubility, low viscosity, buoyancy, and compressibility) is essential in obtaining a successful CO2 angiogram and in guiding endovascular intervention. Unlike iodinated contrast material, CO2 displaces the blood and produces a negative contrast for digital subtraction imaging. Indications for use of CO2 as a contrast agent include: aortography and runoff, detection of bleeding, renal transplant arteriography, portal vein visualization with wedged hepatic venous injection, venography, arterial and venous interventions, and endovascular aneurysm repair. CO2 should not be used in the thoracic aorta, the coronary artery, and cerebral circulation. Exploitation of CO2 properties, avoidance of air contamination and facile catheterization technique are important to the safe and effective performance of CO2 angiography and CO2-guided endovascular intervention. PMID:26509137

  5. Automated myocardial perfusion from coronary x-ray angiography

    Science.gov (United States)

    Storm, Corstiaan J.; Slump, Cornelis H.

    2010-03-01

    The purpose of our study is the evaluation of an algorithm to determine the physiological relevance of a coronary lesion as seen in a coronary angiogram. The aim is to extract as much as possible information from a standard coronary angiogram to decide if an abnormality, percentage of stenosis, as seen in the angiogram, results in physiological impairment of the blood supply of the region nourished by the coronary artery. Coronary angiography, still the golden standard, is used to determine the cause of angina pectoris based on the demonstration of an important stenose in a coronary artery. Dimensions of a lesion such as length and percentage of narrowing can at present easily be calculated by using an automatic computer algorithm such as Quantitative Coronary Angiography (QCA) techniques resulting in just anatomical information ignoring the physiological relevance of the lesion. In our study we analyze myocardial perfusion images in standard coronary angiograms in rest and in artificial hyperemic phases, using a drug e.g. papaverine intracoronary. Setting a Region of Interest (ROI) in the angiogram without overlying major vessels makes it possible to calculate contrast differences as a function of time, so called time-density curves, in the basal and hyperemic phases. In minimizing motion artifacts, end diastolic images are selected ECG based in basal and hyperemic phase in an identical ROI in the same angiographic projection. The development of new algorithms for calculating differences in blood supply in the region as set are presented together with the results of a small clinical case study using the standard angiographic procedure.

  6. Component-Based Approach in Learning Management System Development

    Science.gov (United States)

    Zaitseva, Larisa; Bule, Jekaterina; Makarov, Sergey

    2013-01-01

    The paper describes component-based approach (CBA) for learning management system development. Learning object as components of e-learning courses and their metadata is considered. The architecture of learning management system based on CBA being developed in Riga Technical University, namely its architecture, elements and possibilities are…

  7. 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 sp...

  8. 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.

  9. Coronary CT Angiography versus Conventional Cardiac Angiography for Therapeutic Decision Making in Patients with High Likelihood of Coronary Artery Disease

    NARCIS (Netherlands)

    Moscariello, Antonio; Vliegenthart, Rozemarijn; Schoepf, U. Joseph; Nance, John W.; Zwerner, Peter L.; Meyer, Mathias; Townsend, Jacob C.; Fernandes, Valerian; Steinberg, Daniel H.; Fink, Christian; Oudkerk, Matthijs; Bonomo, Lorenzo; O'Brien, Terrence X.; Henzler, Thomas

    2012-01-01

    Purpose: To assess the efficacy of coronary computed tomographic (CT) angiography for therapeutic decision making in patients with high likelihood of coronary artery disease (CAD)-specifically the ability of coronary CT angiography to help differentiate patients without and patients with a need for

  10. 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.

  11. 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.

  12. Comparison of digital subtraction angiography, CT angiography, and ultrasonic doppler examination in the evaluation of penile arterial lesions

    Energy Technology Data Exchange (ETDEWEB)

    Kawanisi, Yasuo; Kimura, Kazunori; Lee, Kyong Soo; Koizumi, Takahiro; Nakatsuji, Hiroyoshi; Kojima, Keiji; Yamamoto, Akira; Numata, Akira [Takamatsu Red Cross Hospital (Japan)

    2001-11-01

    CT angiography reconstructed by a multidetector-row helical CT scanner is a newly developed form of imaging. We compared CT angiography and ultrasonic Doppler examination with digital subtraction angiography (DSA) in the diagnosis of arterial lesion. Eighteen patients with arteriogenic erectile dysfunction (ED) underwent color Doppler study DSA, and CT angiography after providing informed consent. The CT angiography images were obtained by a multidetector-row helical CT scanner, Asteion TSX021A (TOSHIBA). We injected prostaglandin E{sub 1} into the penile cavernous body, and then rapidly infused nonionic contrast medium into the antecubital vein. DSA and CT angiography images of the bilateral internal pudendal arteries and cavernous arteries were examined for stenotic lesions or occlusion. We also compared the peak systolic blood flow velocity in the cavernous artery measured by color Doppler ultrasound with CT angiography and DSA. The CT anigography and color Doppler studies were performed on an outpatient basis, but DSA required hospitalization. In the 36 internal pudendal arteries, DSA represented 22 normal arteries and 14 stenosis or occlusions. CT angiography showed 15 normal arteries and 21 occlusions. For the diagnosis of stenosis or occlusion in the internal pudendal artery, the CT angiography image had a good agreement, with a sensitivity of 1.00, specificity of 0.68, and accuracy of 0.81. For diagnosis in the cavernous artery, CT angiography image also showed a good agreement with DSA; however, the quality of the images of fine arteries was better in the DSA images. The inferior view and internal view of the pelvis in CT angiography were helpful for visulaizing the internal pudendal artery, especially at the pubic bone. There was insufficient correlation between peak systolic blood flow velocity and DSA findings. There were no serious complications involved in either examination. CT angiography has not yet reached the same level as DSA in the evaluation

  13. 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.

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

    OpenAIRE

    J. C. Chimal-Eguía; K. Ramírez-Amáro

    2012-01-01

    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 data representation is based on information obtained by image axis division into boxes. The difference between this new input data representation and the classical is that this technique is not time-dependent. This new information is implemented in the new Image-Based Learning A...

  15. Intelligent Flowcharting Developmental Approach to Legal Knowledge Based System

    OpenAIRE

    Nitin Balaji Bilgi; Kulkarni, R. V.

    2011-01-01

    The basic aim of this research, described in this paper is to develop a hybrid legal expert system/ knowledge based system, with specific reference to the transfer of property act, within the Indian legal system which is often in demand. In this paper the authors discuss an traditional approach to combining two types of reasoning methodologies, Rule Based Reasoning (RBR) and Case Based Reasoning (CBR). In RBR module we have interpreted and implemented rules that occur in legal statutes of the...

  16. Biomarker Discovery by Novel Sensors Based on Nanoproteomics Approaches

    Directory of Open Access Journals (Sweden)

    Manuel Fuentes

    2012-02-01

    Full Text Available During the last years, proteomics has facilitated biomarker discovery by coupling high-throughput techniques with novel nanosensors. In the present review, we focus on the study of label-based and label-free detection systems, as well as nanotechnology approaches, indicating their advantages and applications in biomarker discovery. In addition, several disease biomarkers are shown in order to display the clinical importance of the improvement of sensitivity and selectivity by using nanoproteomics approaches as novel sensors.

  17. 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.

  18. 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.

  19. An approach towards problem-based learning in virtual space

    OpenAIRE

    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 pla...

  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. 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.

  2. A New Classification Approach Based on Multiple Classification Rules

    OpenAIRE

    Zhongmei Zhou

    2014-01-01

    A good classifier can correctly predict new data for which the class label is unknown, so it is important to construct a high accuracy classifier. Hence, classification techniques are much useful in ubiquitous computing. Associative classification achieves higher classification accuracy than some traditional rule-based classification approaches. However, the approach also has two major deficiencies. First, it generates a very large number of association classification rules, especially when t...

  3. 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.

  4. 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.

  5. 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).

  6. 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. PMID:26995351

  7. 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.

  8. 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.

  9. Measuring approaches to learning in a problem based learning context

    Directory of Open Access Journals (Sweden)

    Diana H. Dolmans

    2010-07-01

    Full Text Available Objectives: Students in Problem-Based Learning (PBL are assumed to adopt a deep learning approach and not a surface approach. This study investigated: 1 the reliability and validity of version of the Revised Study Process Questionnaire adapted to the PBL context (PBL-R-SPQ and 2 the extent to which PBL students use deep or surface approaches, and whether this differs between first and second year students. Methods: The items of the R-SPQ were reformulated to better fit with a PBL environment, resulting in the PBL-R-SPQ. In total 262 students from MaastrichtMedicalSchool responded to the PBL-R-SPQ. Results: A Confirmatory Factor Analysis (CFA demon-strated that a 9-item Deep Approach scale and a 9-item Surface Approach scale fitted the observed set of data well. Cronbach alphas for the Deep and Surface scales were 0.76 and 0.74, respectively. First year students reported signifi cantly higher Deep Approach scores (M = 3.60, SD = .48 than second year students (M = 3.40, SD = .48 (p = .001, d = .42. Conversely, second year students reported signifi-cantly higher Surface Approach scores, (M = 2.45, SD = .48 than first year students (M = 2.26, SD = .52 (p = .003, d = .38. Conclusions: The 18-item PBL-R-SPQ provides a valid and reliable tool to measure students' learning approach in PBL. In addition, PBL students tended to adopt a deep approach rather than a surface approach, which is in line with the assumptions behind PBL, although the second year students have a somewhat less deep approach than the first year students.

  10. 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.)

  11. Efficacy and safety of dual-axis rotational coronary angiography versus conventional angiography

    International Nuclear Information System (INIS)

    Background:Conventional coronary angiography (CA) is the gold standard for the diagnosis of coronary artery disease. However, this technique requires several orthogonal projections to determine the severity of the disease. Dual-axis rotational coronary angiography (DARCA) is a new technique which acquires the image of each coronary artery using a single contrast injection, potentially reducing both radiation and contrast exposure. Objective: The aim of this study was to determine the amount of contrast used, radiation exposure and diagnostic accuracy of DARCA compared to conventional CA. Methods: We conducted a prospective, self-controlled study of consecutive patients undergoing elective coronary angiography to compare DARCA versus the conventional technique. All the angiographies were reviewed by two independent interventional cardiologists (observer 1 and observer 2) who evaluated agreement between both types of images. The observers evaluated firstly DARCA and three weeks later conventional CA images to prevent bias in their interpretation. Results: The contrast volume used in the diagnostic procedure was significantly lower with DARCA (33.29 ± 11.2 ml vs. 17±5.4 ml; p < 0.01). Radiation exposure in the patient (235.6 ± 76.8 mGy vs. 82.7 ± 46.6 mGy; p <0.01) and operator was also significantly lower (5.7 ± 3.26 μSv vs. 2.48 ± 1.47 μSv; p <0.04). A slight difference and a strong correlation were seen in the number of lesions, vessel diameter and percentage of stenosis between both observers and both methods. Categorical assessment of percentage of stenosis also showed adequate agreement. Conclusion: DARCA reduces the use of contrast agents and radiation exposure compared to the conventional technique without modifying the diagnostic accuracy of the method. (authors)

  12. Stereoscopic vascular models of the head and neck: A computed tomography angiography visualization.

    Science.gov (United States)

    Cui, Dongmei; Lynch, James C; Smith, Andrew D; Wilson, Timothy D; Lehman, Michael N

    2016-01-01

    Computer-assisted 3D models are used in some medical and allied health science schools; however, they are often limited to online use and 2D flat screen-based imaging. Few schools take advantage of 3D stereoscopic learning tools in anatomy education and clinically relevant anatomical variations when teaching anatomy. A new approach to teaching anatomy includes use of computed tomography angiography (CTA) images of the head and neck to create clinically relevant 3D stereoscopic virtual models. These high resolution images of the arteries can be used in unique and innovative ways to create 3D virtual models of the vasculature as a tool for teaching anatomy. Blood vessel 3D models are presented stereoscopically in a virtual reality environment, can be rotated 360° in all axes, and magnified according to need. In addition, flexible views of internal structures are possible. Images are displayed in a stereoscopic mode, and students view images in a small theater-like classroom while wearing polarized 3D glasses. Reconstructed 3D models enable students to visualize vascular structures with clinically relevant anatomical variations in the head and neck and appreciate spatial relationships among the blood vessels, the skull and the skin. PMID:25929248

  13. Cerebral Arteries Extraction using Level Set Segmentation and Adaptive Tracing for CT Angiography

    International Nuclear Information System (INIS)

    We propose an approach for extracting cerebral arteries from partial Computed Tomography Angiography (CTA). The challenges of extracting cerebral arteries from CTA come from the fact that arteries are usually surrounded by bones and veins in the lower portion of a CTA volume. There exists strong intensity-value overlap between vessels and surrounding objects. Besides, it is inappropriate to assume the 2D cross sections of arteries are circle or ellipse, especially for abnormal vessels. The navigation of the arteries could change suddenly in the 3D space. In this paper, a method based on level set segmentation is proposed to target this challenging problem. For the lower portion of a CTA volume, we use geodesic active contour method to detect cross section of arteries in the 2D space. The medial axis of the artery is obtained by adaptively tracking along its navigation path. This is done by finding the minimal cross section from cutting the arteries under different angles in the 3D spherical space. This method is highly automated, with minimum user input of providing only the starting point and initial navigation direction of the arteries of interests

  14. 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.

  15. 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.

  16. Adaptive thresholding of digital subtraction angiography images

    Science.gov (United States)

    Sang, Nong; Li, Heng; Peng, Weixue; Zhang, Tianxu

    2005-10-01

    In clinical practice, digital subtraction angiography (DSA) is a powerful technique for the visualization of blood vessels in the human body. Blood vessel segmentation is a main problem for 3D vascular reconstruction. In this paper, we propose a new adaptive thresholding method for the segmentation of DSA images. Each pixel of the DSA images is declared to be a vessel/background point with regard to a threshold and a few local characteristic limits depending on some information contained in the pixel neighborhood window. The size of the neighborhood window is set according to a priori knowledge of the diameter of vessels to make sure that each window contains the background definitely. Some experiments on cerebral DSA images are given, which show that our proposed method yields better results than global thresholding methods and some other local thresholding methods do.

  17. 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

  18. 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.

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

    International Nuclear Information System (INIS)

    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. (author)

  20. 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.

  1. 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...

  2. 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...

  3. Ant Colony Based Approach for Solving FPGA routing

    Directory of Open Access Journals (Sweden)

    Vinay Chopra

    2011-07-01

    Full Text Available This paper is based on an ant colony optimization algorithm (ASDR for solving FPGA routing for a route based routing constraint model in FPGA design architecture. In this approach FPGA routing task is transformed into a Boolean Satisfiabilty (SAT equation with the property that any assignment of input variables that satisfies the equation specifies a valid route. The Satisfiability equation is then modeled as Constraint Satisfaction problem, which helps in reducing procedural programming. Satisfying assignment for particular route will result in a valid routing and absence of a satisfying assignment implies that the layout is unroutable. In second step ant colony optimization algorithm is applied on the Boolean equation for solving routing alternatives utilizing approach of hard combinatorial optimization problems. The experimental results suggest that the developed ant colony optimization algorithm based router has taken extremely short CPU time as compared to classical Satisfiabilty based detailed router (SDR and finds all possible routes even for large FPGA circuits.

  4. Diffraction tomography on curved boundaries: A projection-based approach

    CERN Document Server

    Clement, G T

    2013-01-01

    An approach to diffraction tomography is investigated for two-dimensional image reconstruction of objects surrounded by an arbitrarily-shaped curve of sources and receivers. Based on the integral theorem of Helmholtz and Kirchhoff, the approach relies upon a valid choice of the Green's functions for selected conditions along the (possibly-irregular) boundary. This allows field projections from the receivers to an arbitrary external location. When performed over all source locations, it will be shown that the field caused by a hypothetical source at this external location is also known along the boundary. This field can then be projected to new external points that may serve as a virtual receiver. Under such a reformation, data may be put in a form suitable for image construction by synthetic aperture methods. Foundations of the approach are shown, followed by a mapping technique optimized for the approach. Examples formed from synthetic data are provided.

  5. 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.

  6. Scattered Data Processing Approach Based on Optical Facial Motion Capture

    OpenAIRE

    Qiang Zhang; Xiaoying Liang; Xiaopeng Wei

    2013-01-01

    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 ...

  7. A genetic programming based business process mining approach

    OpenAIRE

    Turner, Christopher James

    2009-01-01

    As business processes become ever more complex there is a need for companies to understand the processes they already have in place. To undertake this manually would be time consuming. The practice of process mining attempts to automatically construct the correct representation of a process based on a set of process execution logs. The aim of this research is to develop a genetic programming based approach for business process mining. The focus of this research is on automated/semi automat...

  8. Integration Issues of an Ontology based Context Modelling Approach

    OpenAIRE

    Strang, Thomas; Linnhoff-Popien, Claudia; Frank, Korbinian

    2003-01-01

    In this paper we analyse the applicability of our ontology based context modelling approach, considering a range of use cases. After wrapping up the model and the Context Ontology Language (CoOL) derived from it, we introduce some interesting applications of the language, based on a scenario showing the challenges in context aware service interactions. We focus on two submodels of our model for context aware service interactions, namely Context Bindings and Context Obligations, and demonstrat...

  9. 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...

  10. A Learning Object Approach To Evidence based learning

    OpenAIRE

    Zabin Visram; Bruce Elson; Patricia Reynolds

    2005-01-01

    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 mea...

  11. Face Recognition Approach Based on Wavelet - Curvelet Technique

    Directory of Open Access Journals (Sweden)

    Muzhir Shaban Al-Ani

    2012-04-01

    Full Text Available In this paper, a novel face recognition approach based on wavelet-curvelet technique, is proposed. This algorithm based on the similarities embedded in the images, That utilize the wavelet-curvelet technique to extract facial features. The implemented technique can overcome on the other mathematical image analysis approaches. This approaches may suffered from the potential for a high dimensional feature space, Therefore it aims to reduce the dimensionality that reduce the required computational power and memory size. Then the Nearest Mean Classifier (NMC is adopted to recognize different faces. In this work, three major experiments were done. two face databases (MAFD & ORL, and higher recognition rate is obtained by the implementation of this techniques.

  12. 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…

  13. 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...

  14. 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

  15. 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...

  16. 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 pr...

  17. 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…

  18. A Genre-Based Approach to Teaching EFL Summary Writing

    Science.gov (United States)

    Chen, Yuan-Shan; Su, Shao-Wen

    2012-01-01

    This study utilizes a pre-test/post-test assessment to investigate the instructional efficacy of a genre-based approach to teaching summary writing. Forty-one EFL university students in Taiwan were asked before and after the instruction to summarize a simplified version of The Adventures of Tom Sawyer in a maximum of 500 words. All the students'…

  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. 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....

  1. Content Based Image Retrieval and Information Theory: A General Approach.

    Science.gov (United States)

    Zachary, John; Iyengar, S. S.; Barhen, Jacob

    2001-01-01

    Proposes an alternative real valued representation of color based on the information theoretic concept of entropy. A theoretical presentation of image entropy is accompanied by a practical description of the merits and limitations of image entropy compared to color histograms. Results suggest that image entropy is a promising approach to image…

  2. 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.

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

    International Nuclear Information System (INIS)

    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 (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 μm 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 μm 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 μm diameter) are approximately 192±21 and 313±38 μm for the 3D RMA and FPD data, respectively. In addition, for the dual-acquisition 3D RMA, FFOV FPD data need not be of the highest quality, and thus may be acquired at lower dose

  4. Cerebral blood flow imaged with ultrahigh-resolution optical coherence angiography and Doppler tomography

    OpenAIRE

    Ren, Hugang; Du, Congwu; Pan, Yingtian

    2012-01-01

    Speckle contrast based optical coherence angiography (OCA) and optical coherence Doppler tomography (ODT) have been applied to image cerebral blood flow previously. However, the contrast mechanisms of these two methods are not fully studied. Here, we present both flow phantom and in vivo animal experiments using ultrahigh-resolution OCA (μOCA) and ODT (μODT) to investigate the flow sensitivity differences between these two methods. Our results show that the high sensitivity of μOCA for visual...

  5. Computed Tomographic Angiography under Sedation in the Diagnosis of Suspected Canine Pancreatitis: A Pilot Study

    OpenAIRE

    Adrian, A.M.; Twedt, D.C.; Kraft, S L; Marolf, A.J.

    2014-01-01

    Background Computed tomography (CT) is highly accurate for diagnosing pancreatitis in humans. The diagnosis of pancreatitis in dogs is based on clinical signs, laboratory findings, and ultrasonographic (US) changes. There are, however, inherent limitations in relying on laboratory and ultrasound findings for the clinical diagnosis of pancreatitis in dogs. Hypothesis/Objectives We hypothesized that CT angiography would be a rapid and reliable method to confirm pancreatitis in dogs compared to ...

  6. Indocyanine Green Angiography Guided Management of Vogt-Koyanagi-Harada Disease

    OpenAIRE

    Nadia Bouchenaki; Herbort, Carl P.

    2011-01-01

    Purpose: To report the management of Vogt-Koyanagi-Harada (VKH) disease based on indocyanine green angiography (ICGA). Methods: VKH patients with acute episodes of inflammation (inaugural or recurrent) who had received standard ICGA-guided care were studied retrospectively. Standard of care included high dose systemic corticosteroids at presentation and close ICGA follow-up with addition of immunosuppressive agents and/or intensification of ongoing therapy when recurrent choroidal lesions wer...

  7. 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.   

  8. 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%.

  9. 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

  10. 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%.

  11. 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

  12. 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

  13. Revising a design course from a lecture approach to a project-based learning approach

    Science.gov (United States)

    Kunberger, Tanya

    2013-06-01

    In order to develop the evaluative skills necessary for successful performance of design, a senior, Geotechnical Engineering course was revised to immerse students in the complexity of the design process utilising a project-based learning (PBL) approach to instruction. The student-centred approach stresses self-directed group learning, which focuses on the process rather than the result and underscores not only the theoretical but also the practical constraints of a problem. The shift in course emphasis, to skills over concepts, results in reduced content coverage but increased student ability to independently acquire a breadth of knowledge.

  14. 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.

  15. The efficiency of magnetic resonance angiography (MRA) in the diagnosis vertebrobasilar insufficiency (VBI)

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Hiroyuki; Ura, Masaharu; Ganaha, Akira; Yasuda, Shinobu; Noda, Yutaka [Ryukyus Univ., Nishihara, Okinawa (Japan). Faculty of Medicine

    2000-09-01

    Vertebrobasilar insufficiency (VBI) is found in many cases of vertigo in patients who visit otolaryngology clinics. But its symptoms tend to be transitory, and since objective findings cannot be obtained at the first examination it is difficult to diagnose. As a result, it is tentatively diagnosed based only on the past history or the outcome of an equilibrium test. It is useful to diagnose circulation insufficiency, the stenotic position or the degree of the vessels based on the angiography findings. However, an operation is dangerous and overly invasive and therefore surgery is often not performed in many cases. We performed magnetic resonance angiography (MRA) and found it to be easy to perform, safe, it required a short examination time and was not invasive. A total of 12 cases suspected to have VBI based on the findings of an equilibrium test, MRA was performed. We could identify the stenotic or obstructive position of the vessels in the vertebrobasilar system in six of the cases. In conclusion, MRA was found to have many advantages over angiography and thus was considered to be useful in making a definite diagnosis of VBI. (author)

  16. 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.

  17. 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.

  18. A Review-Based Reputation Evaluation Approach for Web Services

    Institute of Scientific and Technical Information of China (English)

    Hai-Hua Li; Xiao-Yong Du; Xuan Tian

    2009-01-01

    Web services are commonly perceived as an environment of both offering opportunities and threats.In this environment, one way to minimize threats is to use reputation evaluation, which can be computed, for example, through transaction feedback.However.the current feedback-based approach is inaccurate and inefiective because of its inner limitations(e.g.,feedback quality problem).As the main source of feedback, the qualities of existing on-line reviews are often varied greatly from low to high, the main reasons include:(1)they have no standard expression formats,(2)dishonest comments may exist among these reviews due to malicious attacking.Up to present,the quality problem of review has not been well solved, which greatly degrades their importance on service reputation evaluation. Therefore, we firstly present a novel evaluation approach for review quality in terms of multiple metrics. Then. we make a further improvement in service reputation evaluation based on those filtered reviews. Experimental results show the effectiveness and efficiency of our proposed approach compared with the naive feedback-based approaches.

  19. Style: A Computational and Conceptual Blending-Based Approach

    Science.gov (United States)

    Goguen, Joseph A.; Harrell, D. Fox

    This chapter proposes a new approach to style, arising from our work on computational media using structural blending, which enriches the conceptual blending of cognitive linguistics with structure building operations in order to encompass syntax and narrative as well as metaphor. We have implemented both conceptual and structural blending, and conducted initial experiments with poetry, including interactive multimedia poetry, although the approach generalizes to other media. The central idea is to generate multimedia content and analyze style in terms of blending principles, based on our finding that different principles from those of common sense blending are often needed for some contemporary poetic metaphors.

  20. Ontology based approach for video transmission over the network

    CERN Document Server

    Garg, Rachit Mohan; Tyagi, Neha; 10.5121/ijma.2011.3106

    2011-01-01

    With the increase in the bandwidth & the transmission speed over the internet, transmission of multimedia objects like video, audio, images has become an easier work. In this paper we provide an approach that can be useful for transmission of video objects over the internet without much fuzz. The approach provides a ontology based framework that is used to establish an automatic deployment of video transmission system. Further the video is compressed using the structural flow mechanism that uses the wavelet principle for compression of video frames. Finally the video transmission algorithm known as RRDBFSF algorithm is provided that makes use of the concept of restrictive flooding to avoid redundancy thereby increasing the efficiency.

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

    OpenAIRE

    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 view trace image. We apply the 3D model reconstruction followed by image synthesis approach to the frontal view mug shot images in the suspect reference set in order to create such a virtual suspect r...

  2. Mesh Geometric Editing Approach Based on Gpu Texture

    Directory of Open Access Journals (Sweden)

    Guiping Qian

    2012-09-01

    Full Text Available This paper presents a novel interactive mesh editing approach based on GPU texture mapping. The main feature is that it copies 2D surface geometry information to GPU frame buffer. The planar mesh information is transformed into GPU texture and placed on apposite position of target mesh. 3D information is retrieved after stitching two mesh components from the primitive vertex coordinates. When running real-time mesh cloning operator, our mesh editing approach can copy arbitrary irregular geometric features from source mesh to target mesh. Experimental results indicate that our method can outperform previous related mesh editing techniques.

  3. 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.

  4. Early diagnosis of retinopathy in juvenile diabetes by fluorescence angiography

    International Nuclear Information System (INIS)

    The authors defined the usefulness of the fluorescein angiography of the retina and choroid in the early stage diagnosis of diabetic retinopathy in children comparing its results to the traditional ophthalmoscopy. Examination involved 50 children from 4 to 18 (30 boys and 20 girls) on insulin treatment. The duration of the disease was 1 to 14 years (average 7.36 years). Ophthalmoscopy showed pathological changes in 24% of the children. The fluorescein angiography visualized more microaneurysms compared to ophthalmoscopy and showed them sometimes in the eyes where they had not been found in eye fundus studies. By means of angiography the early and advanced stages of vascular complications were found in 64% of patients. Comparing to ophthalmoscopy a 40% increase was noted. Fluorescein angiography can lead to the decrease in the number of patients with markedly impaired visual acuity and cases of blindness in the diabetic population. (author)

  5. 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

  6. Magnetic Resonance Angiography in the Diagnosis of Cerebral Arteriovenous Malformation and Dural Arteriovenous Fistulas: Comparison of Time-Resolved Magnetic Resonance Angiography and Three Dimensional Time-of-Flight Magnetic Resonance Angiography

    Science.gov (United States)

    Cheng, Yu-Ching; Chen, Hung-Chieh; Wu, Chen-Hao; Wu, Yi-Ying; Sun, Ming-His; Chen, Wen-Hsien; Chai, Jyh-Wen; Chi-Chang Chen, Clayton

    2016-01-01

    Background Traditional digital subtraction angiography (DSA) is currently the gold standard diagnostic method for the diagnosis and evaluation of cerebral arteriovenous malformation (AVM) and dural arteriovenous fistulas (dAVF). Objectives The aim of this study was to analyze different less invasive magnetic resonance angiography (MRA) images, time-resolved MRA (TR-MRA) and three-dimensional time-of-flight MRA (3D TOF MRA) to identify their diagnostic accuracy and to determine which approach is most similar to DSA. Patients and Methods A total of 41 patients with AVM and dAVF at their initial evaluation or follow-up after treatment were recruited in this study. We applied time-resolved angiography using keyhole (4D-TRAK) MRA to perform TR-MRA and 3D TOF MRA examinations simultaneously followed by DSA, which was considered as a standard reference. Two experienced neuroradiologists reviewed the images to compare the diagnostic accuracy, arterial feeder and venous drainage between these two MRA images. Inter-observer agreement for different MRA images was assessed by Kappa coefficient and the differences of diagnostic accuracy between MRA images were evaluated by the Wilcoxon rank sum test. Results Almost all vascular lesions (92.68%) were correctly diagnosed using 4D-TRAK MRA. However, 3D TOF MRA only diagnosed 26 patients (63.41%) accurately. There were statistically significant differences regarding lesion diagnostic accuracy (P = 0.008) and venous drainage identification (P < 0.0001) between 4D-TRAK MRA and 3D TOF MRA. The results indicate that 4D-TRAK MRA is superior to 3D TOF MRA in the assessment of lesions. Conclusion Compared with 3D TOF MRA, 4D-TRAK MRA proved to be a more reliable screening modality and follow-up method for the diagnosis of cerebral AVM and dAVF.

  7. Fatal Deep Inguinal Infection after Diagnostic Coronary Angiography

    OpenAIRE

    Akkoyun, Dursun Çayan; Alpsoy, Şeref; Akyüz, Aydın; Güneş, Hayati

    2015-01-01

    Herein we would like to share our case complicated with inguinal infection secondary to femoral haematoma after coronary angiography. A-79 years-old female underwent diagnostic coronary angiography suffered from a large haematoma in the right inguinal region where femoral artery puncture was performed at another hospital. She was treated at same hospital 16 days and discharged. She presented to our department with a deep ulcerative and ruptured wound in the femoral artery puncture site. The w...

  8. Three-dimensional fusion angiography of a giant basilar aneurysm for coil embolization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joo Yeon; Suh, Dae Chul [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    2015-05-15

    A giant aneurysm was unexpectedly found on computed tomography angiogram in a 54-year-old female. Cerebral angiogram showed a giant aneurysm at the ventral side of the lower basilar artery trunk. However, it was difficult to demonstrate the precise relationship between the aneurysmal sac and the parent artery because of the incomplete filling of the contrast medium secondary to the preferential flows from a well-balanced development of both vertebral arteries. Three-dimensional (3D) fusion angiography revealed complete filling of the aneurysm as well as the basilar trunk itself beyond the aneurysm, which was dysplastic. Coiling of the aneurysm was safely and completely accomplished based on the fusion images. In this report, we demonstrate a case of giant basilar aneurysm with 3D fusion angiography proving useful in assisting with treatment planning.

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

    International Nuclear Information System (INIS)

    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.)

  10. 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.

  11. 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.

  12. MDA based-approach for UML Models Complete Comparison

    Directory of Open Access Journals (Sweden)

    Samia Benabdellah Chaouni

    2011-03-01

    Full Text Available 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.

  13. 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).

  14. An MAS-Based ETL Approach for Complex Data

    CERN Document Server

    Boussaïd, Omar; Darmont, Jérôme

    2008-01-01

    In a data warehousing process, the phase of data integration is crucial. Many methods for data integration have been published in the literature. However, with the development of the Internet, the availability of various types of data (images, texts, sounds, videos, databases...) has increased, and structuring such data is a difficult task. We name these data, which may be structured or unstructured, "complex data". In this paper, we propose a new approach for complex data integration, based on a Multi-Agent System (MAS), in association to a data warehousing approach. Our objective is to take advantage of the MAS to perform the integration phase for complex data. We indeed consider the different tasks of the data integration process as services offered by agents. To validate this approach, we have actually developed an MAS for complex data integration.

  15. 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.

  16. CT Angiography in the Diagnosis of Brain Death

    International Nuclear Information System (INIS)

    Summary Brain death is defined as the irreversible cessation of functioning of the entire brain, including the brainstem. Brain death is principally established using clinical criteria including coma, absence of brainstem reflexes and loss of central drive to breathe assessed with apnea test. In situations in which clinical testing cannot be performed or when uncertainty exists about the reliability of its parts due to confounding conditions ancillary tests (i.a. imaging studies) may be useful. The objective of ancillary tests in the diagnosis of brain death is to demonstrate the absence of cerebral electrical activity (EEG and evoked potentials) or cerebral circulatory arrest. In clinical practice catheter cerebral angiography, perfusion scintigraphy, transcranial Doppler sonography, CT angiography and MR angiography are used. Other methods, like perfusion CT, xenon CT, MR spectroscopy, diffusion weighted MRI and functional MRI are being studied as potentially useful in the diagnosis of brain death. CT angiography has recently attracted attention as a promising alternative to catheter angiography – a reference test in the diagnosis of brain death. Since 1998 several major studies were published and national guidelines were introduced in several countries (e.g. in France, Austria, Switzerland, the Netherlands and Canada). This paper reviews technique, characteristic findings and criteria for the diagnosis of cerebral circulatory arrest in CT angiography

  17. Contrast agent choice for intravenous coronary angiography

    Science.gov (United States)

    Zeman, H. D.; Siddons, D. P.

    1990-05-01

    The screening of the general population for coronary artery disease would be practical if a method existed for visualizing the extent of occlusion after an intravenous injection of contrast agent. Measurements performed with monochromatic synchrotron radiation X-rays and an iodine-containing contrast agent at the Stanford Synchrotron Radiation Laboratory have shown that such an intravenous angiography procedure would be possible with an adequately intense monochromatic X-ray source. Because of the size and cost of synchrotron radiation facilities it would be desirable to make the most efficient use of the intensity available, while reducing as much as possible the radiation dose experienced by the patient. By choosing contrast agents containing elements with a higher atomic number than iodine, it is possible to both improve the image quality and reduce the patient radiation dose, while using the same synchrotron radiation source. By using Si monochromator crystals with a small mosaic spread, it is possible to increase the X-ray flux available for imaging by over an order of magnitude, without any changes in the storage ring or wiggler magnet. The most critical imaging task for intravenous coronary angiography utilizing synchrotron radiation X-rays is visualizing a coronary artery through the left ventricle or aorta which also contain contrast agent. Calculations have been made of the signal to noise ratio expected for this imaging task for various contrast agents with atomic numbers between that of iodine and bismuth. The X-ray energy spectrum of the X-17 superconduction wiggler beam line at the National Synchrotron Light Source at Brookhaven National Laboratory has been used for these calculations. Both perfect Si crystals and Si crystals with a small mosaic spread are considered as monochromators. Contrast agents containing Gd or Yb seem to have about the optimal calculated signal to noise ratio. Gd-DTPA is already approved for use as a contrast agent for

  18. Volume Measurement of Intracranial Aneurysms from 3D Rotational Angiography: Improvement of Accuracy by Gradient Edge Detection

    NARCIS (Netherlands)

    Oliván Bescós, Javier; Slob, Marjan J.; Slump, Cornelis H.; Sluzewski, Menno; Rooij, van Willem Jan

    2005-01-01

    Manual volume measurement of intracranial aneurysms from 3D rotational angiography varies on different threshold settings and, therefore, is operator-dependent. We developed and validated a method based on automatic gradient edge detection that is independent on threshold settings and provides an ac

  19. 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.

  20. 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.

  1. 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 ontol...... of data mining of texts identifying paraphrases and concept relations and measuring distances between key concepts in texts. Thus, the project is distinct in its attempt to provide a formal underpinning of conceptual similarity or relatedness of meaning.......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...... ontologies’, i.e., ontologies providing increasingly specialised concepts reflecting the phrase structure of natural language. Furthermore, we propose a novel so called ontological semantics which maps noun phrases from texts and queries into nodes in the generative ontology. This enables an advanced form...

  2. 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.

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

    International Nuclear Information System (INIS)

    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.)

  4. 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.)

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Nucleic acid-based approaches to STAT inhibition.

    Science.gov (United States)

    Sen, Malabika; Grandis, Jennifer R

    2012-10-01

    Silencing of abnormally activated genes can be accomplished in a highly specific manner using nucleic acid based approaches. The focus of this review includes the different nucleic acid based inhibition strategies such as antisense oligodeoxynucleotides, small interfering RNA (siRNA), dominant-negative constructs, G-quartet oligonucleotides and decoy oligonucleotides, their mechanism of action and the effectiveness of these approaches to targeting the STAT (signal transducer and activator of transcription) proteins in cancer. Among the STAT proteins, especially STAT3, followed by STAT5, are the most frequently activated oncogenic STATs, which have emerged as plausible therapeutic cancer targets. Both STAT3 and STAT5 have been shown to regulate numerous oncogenic signaling pathways including proliferation, survival, angiogenesis and migration/invasion. PMID:24058785

  10. 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

  11. 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.

  12. Approach Based Patterns for System-of-Systems Reconfiguration

    OpenAIRE

    Petitdemange, Franck; Borne, Isabelle; Buisson, Jeremy

    2015-01-01

    International audience Systems-of-systems (SoS) are a particular class of systems that recruit dynamically their constituents to achieve a global goal. To accomodate this approach, the architecture of SoS is usually described by architectural patterns to be instantiated at runtime. Based on the study of an example, we introduce reconfiguration patterns to help reasoning on reconfiguration and maintaining the architectural patterns of the SoS.

  13. REUSING APPROACH FOR SOFTWARE PROCESSES BASED ON SOFTWARE ARCHITECTURES.

    OpenAIRE

    Aoussat, Fadila; Ahmed-Nacer, Mohamed; Oussalah, Mourad Chabane

    2010-01-01

    International audience; Capitalizing and reusing the knowledge in the field of software process engineering is the objective of this work. In order to ensure a high quality for software process models, regarding to the specific needs of new development techniques and methods, we propose an approach based on two essential points: The Capitalization of the knowledge through a domain ontology, and the reusing of this knowledge across handling software process models as software architectures.

  14. Decent work on industrial enterprise based the approach competentive

    OpenAIRE

    Humeniuk, Nataliia

    2013-01-01

    The article proves that achieving decent work possible under the coordination purposes of the enterprise with the goals of employees on the basis of explicit requirements as to such employees to the production process. In connection with the proposed use of the competency approach to create such a system of priorities, and the control scheme of responsibility includes managing staff, working conditions and social processes. Based on the generalization of human resource management processes pr...

  15. A bee colony optimization-based approach for binary optimization

    OpenAIRE

    Kıran, Mustafa Servet; Gündüz, Mesut

    2013-01-01

    The bee colony optimization (BCO) algorithm, one of the swarm intelligence algorithms, is a population based iterative search algorithm. Being inspired by collective bee intelligence, BCO has been proposed for solving discrete optimization problems such as travelling salesman problem. The BCO uses constructive approach for creating a feasible solution for the discrete optimization problems but in this study, we used the solution improvement technique due to nature of the uncapacitated facilit...

  16. A Fuzzy Watermarking Approach Based on the Human Visual System

    OpenAIRE

    Sameh Oueslati, Adnane Cherif & Basel Solaiman

    2010-01-01

    The implementation of our watermarking system is based on a hybrid systemcombining the human visual system (HVS) and the fuzzy inference system (FIS),which always passes through the transcription of human expertise in the form offuzzy rules expressed in natural language, which allows our watermarkingsystem remain understandable for non expert and become more friendly. Thetechnique discussed in this paper is the use of an advanced approach to thetechnique of watermark that is the multi-waterma...

  17. A new flight guidance approach based on differential flatness

    OpenAIRE

    Lu, Wen Chi; Mora-Camino, Félix; Achaibou, Karim

    2004-01-01

    International audience With the sustained increase of air traffic, the demand for new maneuvering capabilities of transport aircrafts is getting more important in order to tackle traffic saturated conditions. In this communication, a new guidance control structure is proposed to perform trajectory tracking through smooth manoeuvers. The design approach is based first on a differential flatness property of aircraft guidance dynamics which is displayed in This work and then on the use of neu...

  18. Logic Minimization Based Approach for Compressing Image Data

    OpenAIRE

    Augustine, Jacob; Feng, Wen; Jacob, James

    1995-01-01

    We propose a novel approach for the lossless compression of binary images using logic minimization. The image is divided into windows or blocks of size $r\\times c$ pixels and each block is transformed into a Boolean switching function in cubical form, treating the pixel values as output of the function. Compression is performed by minimizing these switching functions using ESPRESSO, a cube-based two-level logic minimizer. To reduce the bits required to encode the minimized cubes (product term...

  19. 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.

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

    OpenAIRE

    Hoppenbrouwers, S.J.B.A.; Zoet, M.; Versendaal, J.; van de Weerd, I.

    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 define a framework that conceptualizes an operational way of working for the development of services, emphatically taking into account agility. As a first level of agility, the framework contains sit...

  1. 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.

  2. Lexical transfer in Norwegian interlanguage : A detection-based approach

    OpenAIRE

    2012-01-01

    This study investigates cross-linguistic influence ('transfer') in Norwegian interlanguage using predictive data mining technology and with a focus on lexical transfer. The impetus for the present work came from the publication of a series of studies (Jarvis & Crossley 2012) that explore the 'detection-based approach' to language transfer. The following research questions are addressed: 1. Can data mining techniques be used to identify the L1 background of Norwegian language learners ...

  3. An Ultrasound Image Despeckling Approach Based on Principle Component Analysis

    OpenAIRE

    Jawad F. Al-Asad; Ali M. Reza; Udomchai Techavipoo

    2014-01-01

    An approach based on principle component analysis (PCA) to filter out multiplicative noise from ultrasound images is presented in this paper. An image with speckle noise is segmented into small dyadic lengths, depending on the original size of the image, and the global covariance matrix is found. A projection matrix is then formed by selecting the maximum eigenvectors of the global covariance matrix. This projection matrix is used to filter speckle noise by projecting each segment into the si...

  4. A contextual modeling approach for model-based recommender systems

    OpenAIRE

    Fernández-Tobías, Ignacio; Campos Soto, Pedro G.; Cantador, Iván; Díez, Fernando

    2013-01-01

    The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-40643-0_5 Proceedings of 15th Conference of the Spanish Association for Artificial Intelligence, CAEPIA 2013, Madrid, Spain, September 17-20, 2013. In this paper we present a contextual modeling approach for model-based recommender systems that integrates and exploits both user preferences and contextual signals in a common vector space. Differently to previous work, we conduct a user study acquiring ...

  5. An effective electrostatic-confinement based fusion approach

    OpenAIRE

    R. K. Paul

    2013-01-01

    The paper reports a new electrostatic-confinement based fusion approach, where, a new non-equilibrium distribution function for an ion-beam, compressed by an external electric force, has been derived. This distribution function allows the system to possess appreciably low and insignificant thermal energy irrespective of the energy per particle. The spread in the energy among the particles is attributed to the collisions in presence of the external force, whereas; for equilibrium, the spreadin...

  6. DIRECT APPROACH FOR SOLITON PERTURBATIONS BASED ON THE GREEN'S FUNCTION

    Institute of Scientific and Technical Information of China (English)

    PAN LIU-XIAN; YAN JIA-REN; ZHOU GUANG-HUI

    2001-01-01

    A direct approach has been developed for soliton perturbations based on the Green's function. We first linearized the soliton equation, and then derived the Green's function corresponding to approximation equations of different orders. Finally, we obtained the effects of perturbation on a soliton, namely both the slow time dependence of the soliton parameters and the corrections up to the second-order approximation. The higher-order effects can also be obtained in the same way.

  7. 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.

  8. Unusual Congenital Aortic Anomaly with Rare Common Celiamesenteric Trunk Variation: MR Angiography and Digital Substraction Angiography Findings

    International Nuclear Information System (INIS)

    Magnetic resonance angiography and digital substraction angiography (DSA) findings in a case with a rare congenital thoracoabdominal aortic hypoplasia and common celiamesenteric trunk variation with occlusion of infrarenal abdominal aorta are described here. To our knowledge, this aortic anomaly has not been previously described in the English literature. DSA is the optimum imaging modality for determination of aortic hypoplasia, associated vascular malformations, collateral vessels, and direction of flow within vessels

  9. A Wavelet-Based Approach to Pattern Discovery in Melodies

    DEFF Research Database (Denmark)

    Velarde, Gissel; Meredith, David; Weyde, Tillman

    2016-01-01

    We present a computational method for pattern discovery based on the application of the wavelet transform to symbolic representations of melodies or monophonic voices. We model the importance of a discovered pattern in terms of the compression ratio that can be achieved by using it to describe...... transform (CWT) at a single scale using the Haar wavelet. These representations are segmented using various approaches and the segments are then concatenated based on their similarity. The concatenated segments are compared, clustered and ranked. The method was evaluated on two musicological tasks...

  10. A New Approach to Image Fusion Based on Cokriging

    Science.gov (United States)

    Memarsadeghi, Nargess; LeMoigne, Jacqueline; Mount, David M.; Morisette, Jeffrey T.

    2005-01-01

    We consider the image fusion problem involving remotely sensed data. We introduce cokriging as a method to perform fusion. We investigate the advantages of fusing Hyperion with ALI. The evaluation is performed by comparing the classification of the fused data with that of input images and by calculating well-chosen quantitative fusion quality metrics. We consider the Invasive Species Forecasting System (ISFS) project as our fusion application. The fusion of ALI with Hyperion data is studies using PCA and wavelet-based fusion. We then propose utilizing a geostatistical based interpolation method called cokriging as a new approach for image fusion.

  11. GPC Using a Delta-Domain Emulator-Based Approach

    DEFF Research Database (Denmark)

    Lauritsen, Morten Bach; Jensen, Morten Rostgaard; Poulsen, Niels Kjølstad

    1997-01-01

    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......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...

  12. Fragment-based approaches and computer-aided drug discovery.

    Science.gov (United States)

    Rognan, Didier

    2012-01-01

    Fragment-based design has significantly modified drug discovery strategies and paradigms in the last decade. Besides technological advances and novel therapeutic avenues, one of the most significant changes brought by this new discipline has occurred in the minds of drug designers. Fragment-based approaches have markedly impacted rational computer-aided design both in method development and in applications. The present review illustrates the importance of molecular fragments in many aspects of rational ligand design, and discusses how thinking in "fragment space" has boosted computational biology and chemistry. PMID:21710380

  13. 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.

  14. 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.)

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

    International Nuclear Information System (INIS)

    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

  16. 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

  17. 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.

  18. Application of a swarm-based approach for phase unwrapping

    Science.gov (United States)

    da S. Maciel, Lucas; Albertazzi G., Armando, Jr.

    2014-07-01

    An algorithm for phase unwrapping based on swarm intelligence is proposed. The novel approach is based on the emergent behavior of swarms. This behavior is the result of the interactions between independent agents following a simple set of rules and is regarded as fast, flexible and robust. The rules here were designed with two purposes. Firstly, the collective behavior must result in a reliable map of the unwrapped phase. The unwrapping reliability was evaluated by each agent during run-time, based on the quality of the neighboring pixels. In addition, the rule set must result in a behavior that focuses on wrapped regions. Stigmergy and communication rules were implemented in order to enable each agent to seek less worked areas of the image. The agents were modeled as Finite-State Machines. Based on the availability of unwrappable pixels, each agent assumed a different state in order to better adapt itself to the surroundings. The implemented rule set was able to fulfill the requirements on reliability and focused unwrapping. The unwrapped phase map was comparable to those from established methods as the agents were able to reliably evaluate each pixel quality. Also, the unwrapping behavior, being observed in real time, was able to focus on workable areas as the agents communicated in order to find less traveled regions. The results were very positive for such a new approach to the phase unwrapping problem. Finally, the authors see great potential for future developments concerning the flexibility, robustness and processing times of the swarm-based algorithm.

  19. 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...

  20. Postmodern Fuzzy System Theory: A Deconstruction Approach Based on Kabbalah

    Directory of Open Access Journals (Sweden)

    Gabriel Burstein

    2014-11-01

    Full Text Available Modern general system theory proposed a holistic integrative approach based on input-state-output dynamics as opposed to the traditional reductionist detail based approach. Information complexity and uncertainty required a fuzzy system theory, based on fuzzy sets and fuzzy logic. While successful in dealing with analysis, synthesis and control of technical engineering systems, general system theory and fuzzy system theory could not fully deal with humanistic and human-like intelligent systems which combine technical engineering components with human or human-like components characterized by their cognitive, emotional/motivational and behavioral/action levels of operation. Such humanistic systems are essential in artificial intelligence, cognitive and behavioral science applications, organization management and social systems, man-machine systems or human factor systems, behavioral knowledge based economics and finance applications. We are introducing here a “postmodern fuzzy system theory” for controlled state dynamics and output fuzzy systems and fuzzy rule based systems using our earlier postmodern fuzzy set theory and a Kabbalah possible worlds model of modal logic and semantics type. In order to create a postmodern fuzzy system theory, we “deconstruct” a fuzzy system in order to incorporate in it the cognitive, emotional and behavioral actions and expressions levels characteristic for humanistic systems. Kabbalah offers a structural, fractal and hierarchic model for integrating cognition, emotions and behavior. We obtain a canonic deconstruction for a fuzzy system into its cognitive, emotional and behavioral fuzzy subsystems.

  1. 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. 

  2. 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.

  3. 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.

  4. EFFICIENT APPROACH TO DISCOVER INTERVAL-BASED SEQUENTIAL PATTERNS

    Directory of Open Access Journals (Sweden)

    R. Sadasivam

    2013-01-01

    Full Text Available In most of the sequential pattern mining methodology they have concentrated only on time point base event data. But some research efforts have detailed the mining patterns from time interval based event data. In many application most of the events are occurred at time interval based event not a point based interval for example patient affected by the certain time period. Our goal is to mine the frequently occurred sequential patterns in the database. In this study we have introduced a new algorithm namely KPrefixspan by modifying the TPrefixspan algorithm to overcome the demerits of that algorithm. Here new approach called refined database can reduce the scanning time extremely since the unsupported events are removed at each projection also result of the sequential pattern is extremely precise. Experiments constructed for synthetic datasets. From the experimental results we reduced the running time almost 60% and also reduce the memory usage almost 25% when compared to the existing TPrefixspan algorithm.

  5. 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.

  6. CT Angiography of the Coronary Arteries

    Directory of Open Access Journals (Sweden)

    H.Ghanaati

    2005-08-01

    Full Text Available Introduction & Background: Cardiac imaging is currently one the most rapidly advancing fields in clinical cardiology. Continuing technical innovations are expanding the applicability and usefulness of non-invasive imaging modalities such as ultrasound, nuclear imaging, positron emis-sion tomography Magnetic Resonance Imaging and most recently computed tomography (CT. In 1998, the 4-slice spiral CT scanners were introduced with a rotation time of 500ms a collimated detector width varying from 0.5 to 1.25mm. In 2002, the 16-slice spiral CT scanners were first used for coronary imag-ing. The rotation time and some of these scanners is now less than 400ms, the slice thickness varies be-tween 0.5 and 0.75mm, and a complete cardiac scan can be performed in less than 20s. In 2004, 64-slice spiral CT released into the market. Imaging of the heart requires acquisition or image reconstruction that is synchronized to the motion of the heart. Nie-man et al, irrespectively of the image quality, evalu-ated all branches with a minimal luminal diameter of 2.0mm and sensitivity and specificity of 95% and 86% respectively in comparison to angiography.

  7. Automatic centerline extraction of coronary arteries in coronary computed tomographic angiography.

    Science.gov (United States)

    Yang, Guanyu; Kitslaar, Pieter; Frenay, Michel; Broersen, Alexander; Boogers, Mark J; Bax, Jeroen J; Reiber, Johan H C; Dijkstra, Jouke

    2012-04-01

    Coronary computed tomographic angiography (CCTA) is a non-invasive imaging modality for the visualization of the heart and coronary arteries. To fully exploit the potential of the CCTA datasets and apply it in clinical practice, an automated coronary artery extraction approach is needed. The purpose of this paper is to present and validate a fully automatic centerline extraction algorithm for coronary arteries in CCTA images. The algorithm is based on an improved version of Frangi's vesselness filter which removes unwanted step-edge responses at the boundaries of the cardiac chambers. Building upon this new vesselness filter, the coronary artery extraction pipeline extracts the centerlines of main branches as well as side-branches automatically. This algorithm was first evaluated with a standardized evaluation framework named Rotterdam Coronary Artery Algorithm Evaluation Framework used in the MICCAI Coronary Artery Tracking challenge 2008 (CAT08). It includes 128 reference centerlines which were manually delineated. The average overlap and accuracy measures of our method were 93.7% and 0.30 mm, respectively, which ranked at the 1st and 3rd place compared to five other automatic methods presented in the CAT08. Secondly, in 50 clinical datasets, a total of 100 reference centerlines were generated from lumen contours in the transversal planes which were manually corrected by an expert from the cardiology department. In this evaluation, the average overlap and accuracy were 96.1% and 0.33 mm, respectively. The entire processing time for one dataset is less than 2 min on a standard desktop computer. In conclusion, our newly developed automatic approach can extract coronary arteries in CCTA images with excellent performances in extraction ability and accuracy. PMID:21637981

  8. 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.

  9. 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.

  10. Modern Perforator Flap Imaging with High-Resolution Blood Pool MR Angiography.

    Science.gov (United States)

    Kagen, Alexander C; Hossain, Rydhwana; Dayan, Erez; Maddula, Soumya; Samson, William; Dayan, Joseph; Smith, Mark L

    2015-01-01

    Advances in microsurgical techniques have improved autologous reconstructions by providing new donor site options while decreasing donor site morbidity. Various preoperative imaging modalities have been studied to assess the relevant vascular anatomic structures, with magnetic resonance (MR) angiography traditionally lagging behind computed tomography (CT) with respect to spatial resolution. Blood pool MR angiography with gadofosveset trisodium, a gadolinium-based contrast agent with extended intravascular retention, has allowed longer multiplanar acquisitions with resultant voxel sizes similar to or smaller than those of CT and with improved signal-to-noise ratio and soft-tissue contrast while maintaining the ability to depict flow with time-resolved imaging. The resultant vascular detail enables precise evaluation of the relevant vascular anatomic structures, including the vessel course, size, and branching pattern, as well as the venous arborization pattern. In addition, any architectural distortion, vessel alteration, or injury from prior surgery can be depicted. The reporting radiologist should be aware of pertinent and incidental findings relevant to the planned surgery and the patient's disease so that he or she can assist the microsurgeon in flap design as a member of the multidisciplinary team. Given the lack of ionizing radiation exposure in patients who often have an elevated body mass index, high-spatial-resolution blood pool MR angiography has become the imaging reference standard for the preoperative assessment of perforator flap vascular and soft-tissue morphology in our practice. PMID:25884098

  11. 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.

  12. 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.

  13. 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.

  14. SMP-Based Approach for Intelligent Service Interaction

    Directory of Open Access Journals (Sweden)

    Hosam AlHakami

    2014-11-01

    Full Text Available Service-oriented computing is establishing itself as a new computing paradigm in which services advertise their capabilities within a network, and then are used, composed and orchestrated by other services and end-users. Whilst many approaches to matching service providers with consumers of their services have been developed in the past, the proposed approach in this paper takes a different view of the problem in that it does not look for the fittest individual utility, but views it as a constrained optimisation problem that matches between a set of services and a set of service requests. Our approach addresses this problem using an adaptation of the well known stable-marriage problem and demonstrates how matching between services and requests to a certain threshold can be expressed. This will contribute a fair assignment between services and requests based on their preferences. As the current state of the service selection process considers only the view of requests, the proposed approach can ensure several features to the services such as service protection and service quality, e.g. it can ensure the preservation of service availability by redirecting a coming request to a similar service if the current service is busy.

  15. When is rotational angiography superior to conventional single‐plane angiography for planning coronary angioplasty?

    Science.gov (United States)

    Taylor, Jane; Boutong, Sara; Brett, Sarah; Louis, Amal; Heppenstall, James; Morton, Allison C.; Gunn, Julian P.

    2015-01-01

    Objectives To investigate the value of rotational coronary angiography (RoCA) in the context of percutaneous coronary intervention (PCI) planning. Background As a diagnostic tool, RoCA is associated with decreased patient irradiation and contrast use compared with conventional coronary angiography (CA) and provides superior appreciation of three‐dimensional anatomy. However, its value in PCI remains unknown. Methods We studied stable coronary artery disease assessment and PCI planning by interventional cardiologists. Patients underwent either RoCA or conventional CA pre‐PCI for planning. These were compared with the referral CA (all conventional) in terms of quantitative lesion assessment and operator confidence. An independent panel reanalyzed all parameters. Results Six operators performed 127 procedures (60 RoCA, 60 conventional CA, and 7 crossed‐over) and assessed 212 lesions. RoCA was associated with a reduction in the number of lesions judged to involve a bifurcation (23 vs. 30 lesions, P RoCA improved confidence assessing lesion length (P = 0.01), percentage stenosis (P = 0.02), tortuosity (P RoCA augments quantitative lesion assessment, enhances confidence in the assessment of coronary artery disease and the precise details of the proposed procedure, but does not affect X‐ray dose, contrast agent volume, or procedure duration. © 2015 Wiley Periodicals, Inc. PMID:26012725

  16. 经左桡动脉与右桡动脉入路冠状动脉造影术安全性和有效性比较%Safety and efficiency of coronary angiography via left radial artery compared with right radial artery ap-proach

    Institute of Scientific and Technical Information of China (English)

    聂斌; 张维君; 杨清; 马涵英; 王建龙; 周玉杰

    2012-01-01

    目的 探讨经左桡动脉行冠状动脉造影术的安全性和有效性.方法 将463例择期行冠状动脉造影术的患者完全随机分入左桡动脉入路组(231例)和右桡动脉入路组(232例).比较2组患者手术成功率、手术时间、X线透视时间、对比剂用量、单导管技术成功率、血管并发症发生率等.结果 左桡动脉入路组手术成功率98.3%(227/231),右桡动脉入路组手术成功率97.4%(226/232),组间差异无统计学意义(P>0.05).2组手术时间、X线透视时间、对比剂用量、血管并发症发生率、单导管技术成功率等均相似,差异均无统计学意义(均P>0.05).结论 经左桡动脉入路行冠状动脉造影有着与右桡动脉入路相似的成功率和安全性,左桡动脉入路单导管技术完全可行,并且在头臂干迂曲患者中有优势.%Objective To explore the efficiency and safety of coronary angiography (CA)via left radial artery compared with right radial artery approach.Methods All 463 consecutive patients undergoing elective CA were randomized divided into left radial artery group (L-TRA,231 cases)and right radial artery group (R-TRA,232 cases).The study endpoints included procedure success rate,procedure duration,fluoroscopy time,consumption of contrast media,success rate of single catheter technique and vascular related complications.Results Both L-TRA and R-TRA group had similarly high procedure success rate [98.3% (227/231)vs 97.4% (226/232)],and there was no significant difference(P > 0.05).Regarding procedure duration,fluoroscopy time,contrast media dosage,success rate of single catheter and vascular complications,two groups had no significant diffrernce(P >0.05).Conclusions Left radial artery approach has similar safety and efficiency in terms of performing CA compared to right RA.The single catheter technique is feasible in left RA approach.

  17. 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.

  18. Contingent approach to Internet-based supply network integration

    Science.gov (United States)

    Ho, Jessica; Boughton, Nick; Kehoe, Dennis; Michaelides, Zenon

    2001-10-01

    The Internet is playing an increasingly important role in enhancing the operations of supply networks as many organizations begin to recognize the benefits of Internet- enabled supply arrangements. However, the developments and applications to-date do not extend significantly beyond the dyadic model, whereas the real advantages are to be made with the external and network models to support a coordinated and collaborative based approach. The DOMAIN research group at the University of Liverpool is currently defining new Internet- enabled approaches to enable greater collaboration across supply chains. Different e-business models and tools are focusing on different applications. Using inappropriate e- business models, tools or techniques will bring negative results instead of benefits to all the tiers in the supply network. Thus there are a number of issues to be considered before addressing Internet based supply network integration, in particular an understanding of supply chain management, the emergent business models and evaluating the effects of deploying e-business to the supply network or a particular tier. It is important to utilize a contingent approach to selecting the right e-business model to meet the specific supply chain requirements. This paper addresses the issues and provides a case study on the indirect materials supply networks.

  19. An Ultrasound Image Despeckling Approach Based on Principle Component Analysis

    Directory of Open Access Journals (Sweden)

    Jawad F. Al-Asad

    2014-07-01

    Full Text Available An approach based on principle component analysis (PCA to filter out multiplicative noise from ultrasound images is presented in this paper. An image with speckle noise is segmented into small dyadic lengths, depending on the original size of the image, and the global covariance matrix is found. A projection matrix is then formed by selecting the maximum eigenvectors of the global covariance matrix. This projection matrix is used to filter speckle noise by projecting each segment into the signal subspace. The approach is based on the assumption that the signal and noise are independent and that the signal subspace is spanned by a subset of few principal eigenvectors. When applied on simulated and real ultrasound images, the proposed approach has outperformed some popular nonlinear denoising techniques such as 2D wavelets, 2D total variation filtering, and 2D anisotropic diffusion filtering in terms of edge preservation and maximum cleaning of speckle noise. It has also showed lower sensitivity to outliers resulting from the log transformation of the multiplicative noise.

  20. Feedback structure based entropy approach for multiple-model estimation

    Institute of Scientific and Technical Information of China (English)

    Shen-tu Han; Xue Anke; Guo Yunfei

    2013-01-01

    The variable-structure multiple-model (VSMM) approach, one of the multiple-model (MM) methods, is a popular and effective approach in handling problems with mode uncertainties. The model sequence set adaptation (MSA) is the key to design a better VSMM. However, MSA methods in the literature have big room to improve both theoretically and practically. To this end, we propose a feedback structure based entropy approach that could find the model sequence sets with the smallest size under certain conditions. The filtered data are fed back in real time and can be used by the minimum entropy (ME) based VSMM algorithms, i.e., MEVSMM. Firstly, the full Markov chains are used to achieve optimal solutions. Secondly, the myopic method together with particle filter (PF) and the challenge match algorithm are also used to achieve sub-optimal solutions, a trade-off between practicability and optimality. The numerical results show that the proposed algorithm provides not only refined model sets but also a good robustness margin and very high accuracy.

  1. Rigorous Description Of Design Components Functionality: An Approach Based Contract

    Directory of Open Access Journals (Sweden)

    Abdelhafid Zitouni

    2012-01-01

    Full Text Available Current models for software components have made component-based software engineering practical. However, these models are limited in the sense that their support for the characterization/specification of design components primarily deals with syntactic issues. To avoid mismatch and misuse of components, more comprehensive specification of software components is required, In this paper, we present a contract-based approach to analyze and model the both aspects (functional and non-functional properties of design components and their composition in order to detect and correct composition errors. This approach permits to characterize the structural, interface and behavioural aspects of design component. To enable this we present a pattern contract language that captures the structural and behavioral requirements associated with a range of patterns, as well as the system properties that are guaranteed as a result. In addition, we propose the use of the LOTOS language as an ADL for formalizing these aspects. We illustrate the approach by applying it to a standard design pattern.

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

    International Nuclear Information System (INIS)

    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 relatively little morbidity. We extended the principles learned with coronary angiography to noninvasive imaging of the human bronchial tree. For these images, we utilized xenon as the contrast agent, as it has a K-edge very similar to that of iodine. In this case, there is no true competing diagnostic test, and pulmonary neoplasm is an enormous public health concern. In early experiments, we demonstrated remarkably clear images of the human bronchial tree. These images have been shown internationally; however, funding difficulties primarily with the Department of Energy have not allowed for progression of this promising avenue of research. One potential criticism of the project is that in order to obtain these images, we utilized national laboratories. Some have questioned whether this would lead to a practical imaging modality. However, we have shown that the technology exists to allow for construction of a miniature storage ring, with a superconducting

  3. 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

  4. 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

  5. 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. PMID:27198153

  6. 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.

  7. 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.

  8. 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.

  9. A New Design Approach to game or play based learning

    DEFF Research Database (Denmark)

    Larsen, Lasse Juel

    Abstract: The present paper proposes a new design perspective for game based learning. The general idea is to abandon the long and sought after dream of designing a closed learning system, where students from elementary school to high school without teachers’ interference could learn whatever...... game based learning system, but also confront aspects of modern learning theory especially the notion of reference between content of an assignment and the reality with which it should or could be connected (situated learning). The second idea promotes a way to tackle the common experience...... to ground the students sense of meaning. This paper proposes another approach: using visualization in immersive 3D-worlds as documentation of learning progress while at the same time constituting a reward system which motivate further learning. The overall design idea is to build a game based learning...

  10. A Brief Summary of Dictionary Learning Based Approach for Classification

    CERN Document Server

    Shu, Kong

    2012-01-01

    This note presents some representative methods which are based on dictionary learning (DL) for classification. We do not review the sophisticated methods or frameworks that involve DL for classification, such as online DL and spatial pyramid matching (SPM), but rather, we concentrate on the direct DL-based classification methods. Here, the "so-called direct DL-based method" is the approach directly deals with DL framework by adding some meaningful penalty terms. By listing some representative methods, we can roughly divide them into two categories, i.e. (1) directly making the dictionary discriminative and (2) forcing the sparse coefficients discriminative to push the discrimination power of the dictionary. From this taxonomy, we can expect some extensions of them as future researches.

  11. 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...

  12. A Roles-based Approach To Variable-oriented Programming

    Directory of Open Access Journals (Sweden)

    Juha Sorva

    2008-01-01

    Full Text Available Delocalized variable plans pose problems for novice programmers trying to read and write programs. Variable-oriented programming is a programming paradigm that emphasizes the importance of variable-related plans, and localizes actions pertaining to each variable together in one place in the program code. This paper revisits the idea of variable-oriented programming and shows how it can be founded on roles of variables: stereotypes of variable use suitable for teaching to novices. The paper sketches out how variable-oriented, roles-based programming could be implemented using either a new programming language or a framework built on an existing language. The possible applications, merits, and problems of a roles-based approach, and variable-oriented programming in general, are discussed. This paper points toward possible research directions for the future and provides a basis for further discussions of variable-oriented, roles-based programming.

  13. 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.

  14. A Survey on Trust-Based Web Service Provision Approaches

    DEFF Research Database (Denmark)

    Dragoni, Nicola

    2010-01-01

    The basic tenet of Service-Oriented Computing (SOC) is the possibility of building distributed applications on the Web by using Web Services as fundamental building blocks. The proliferation of such services is considered the second wave of evolution in the Internet age, moving the Web from...... a collection of pages to a collections of services. Consensus is growing that this Web Service “revolution” won't eventuate until we resolve trust-related issues. Indeed, the intrinsic openness of the SOC vision makes crucial to locate useful services and recognize them as trustworthy. In this paper we review...... the field of trust-based Web Service selection, providing a structured classification of current approaches and highlighting the main limitations of each class and of the overall field. As a result, we claim that a soft notion of trust lies behind such weaknesses and we advocate the need of a new approach...

  15. 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.

  16. Modeling of Heterogeneous Objects: An Approach Based on Implicit Functions

    Directory of Open Access Journals (Sweden)

    Miller Gómez-Mora

    2016-02-01

    Full Text Available Modeling objects, their properties and relations is an important topic in computer science. In this sense, this research contributes to the framework of heterogeneous solid modeling, as well as the popular and intricate study of implicit solid representation. The approach presented here is broad and generic, but this article will focus on bio-CAD models, alluding to the existing extension and implementation in other fields. The overall aim of this work is to demonstrate that solid models of heterogeneous object can be built implicitly. This is shown to have promise in practical applications from biomedical computing to computer animation and engineering. The approach adopted here is based on the observation that current solid models cannot intrinsically represent multiphase geometric information along with the attribute information. This makes necessary to explore new modeling techniques in order to represent real-world objects. The availability of such modeling techniques remains central to the design, analysis, and fabrication of heterogeneous objects

  17. Alcoholism and its Effects: an Approach Based on Health Psychology

    Directory of Open Access Journals (Sweden)

    Maria de las Mercedes Pretel Olite

    2014-11-01

    Full Text Available Alcoholism is a complex biopsychosocial disorder that requires a specialised and multidisciplinary approach focusing on both the patient and the family. Alcohol consumption is the most important addiction worldwide due to its prevalence and impact. Therefore, the main objective of a primary care physician should be to facilitate the referral of patients and their families to a structured treatment, support and guidance program during the whole detoxification process. In every health area in Cienfuegos, there are community mental health centers with a staff trained to deal with these disorders in addicts and their family. A literature review was conducted to establish the relationship between alcohol consumption and its harmful effects on health, family and society, using an approach based on Health Psychology.

  18. A Systems-Based Approach to Intelligence Reform

    Directory of Open Access Journals (Sweden)

    Austen Givens

    2012-01-01

    Full Text Available The terrorist attacks of September 11, 2001 prompted the most comprehensive changes to the U.S. Intelligence Community (IC since its creation via the National Security Act of 1947. Recent structural and organizational reforms, such as efforts to enhance information sharing and recruit speakers of hard-target languages, have also triggered new challenges to successful transformation. In light of the systemic problems facing the IC, this paper argues that systems engineering, a discipline increasingly useful in organizational change, offers a more efficient, holistic approach to the intelligence reform process than the status quo. Systems engineering views the IC as an integrated and interdependent system, whose value is primarily realized through the relationship among its components. The author makes the case that a systems-based approach to intelligence reform can enhance effectiveness while reducing the risk of unintended consequences.

  19. 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.

  20. Automatic Facial Expression Recognition Based on Hybrid Approach

    Directory of Open Access Journals (Sweden)

    Ali K. K. Bermani

    2012-12-01

    Full Text Available The topic of automatic recognition of facial expressions deduce a lot of researchers in the late last century and has increased a great interest in the past few years. Several techniques have emerged in order to improve the efficiency of the recognition by addressing problems in face detection and extraction features in recognizing expressions. This paper has proposed automatic system for facial expression recognition which consists of hybrid approach in feature extraction phase which represent a combination between holistic and analytic approaches by extract 307 facial expression features (19 features by geometric, 288 feature by appearance. Expressions recognition is performed by using radial basis function (RBF based on artificial neural network to recognize the six basic emotions (anger, fear, disgust, happiness, surprise, sadness in addition to the natural.The system achieved recognition rate 97.08% when applying on person-dependent database and 93.98% when applying on person-independent.

  1. Evolutionary modeling-based approach for model errors correction

    Directory of Open Access Journals (Sweden)

    S. Q. Wan

    2012-08-01

    Full Text Available 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.

  2. 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

  3. 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. PMID:22195072

  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. 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.

  6. Multidetector-Row CT Angiography of Cerebral Vasospasm after Aneurysmal Subarachnoid Hemorrhage: Comparison of Bone Subtraction and Standard CT Angiography with Digital Subtraction Angiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Hee; You, Jin Jong; Choi, Ho Cheol; Kim, Ji Eun [Dept. of Radiology, Gyeongsang National University Hospital, Jinju (Korea, Republic of); Choi, Dae Seob [Gyeongsang Institue of Health Science, Gyeongsang National University School of Medicine, Jinju (Korea, Republic of); Ryoo, Jae Wook [Dept. of Radiology, Samsung Seoul Hospital, Seoul (Korea, Republic of)

    2011-10-15

    To evaluate the usefulness of multidetector-row CT angiography (MDCTA) for the diagnosis of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) by comparison of digital subtraction angiography (DSA) and to compare the bone subtraction CT angiography (BS-CTA) and standard CT angiography (S-CTA). Thirty-three patients who were treated with intraarterial nimodipine infusion for the cerebral vasospasm after aneurysmal SAH were evaluated with MDCTA and DSA. BS-CTA images were reconstructed from the S-CTA and unenhanced CT source images. A total of 207 vascular segments were evaluated. A four-step scale for the degree of stenosis was applied for each segment. With DSA as the standard images, BS-CTA and S-CTA images were comparied. On DSA, 56 segments (27%) presented vasospasm. Concordance between the DSA and S-CTA and between DSA and BS-CTA were 94.7% and 82.1%, respectively. Overestimation for the degree of stenosis was shown in 37 segments on BS-CTA and in 8 segments on S-CTA, but underestimated segments were only shown on S-CTA (n = 4). MDCTA with standard technique seems to be a useful imaging tool for the evaluation of the cerebral vasospasm after aneurysmal SAH. However, BS-CTA is not needed because of additional radiation and overestimation of the degree of stenosis.

  7. A graph-based approach for designing extensible pipelines

    Directory of Open Access Journals (Sweden)

    Rodrigues Maíra R

    2012-07-01

    Full Text Available Abstract Background In bioinformatics, it is important to build extensible and low-maintenance systems that are able to deal with the new tools and data formats that are constantly being developed. The traditional and simplest implementation of pipelines involves hardcoding the execution steps into programs or scripts. This approach can lead to problems when a pipeline is expanding because the incorporation of new tools is often error prone and time consuming. Current approaches to pipeline development such as workflow management systems focus on analysis tasks that are systematically repeated without significant changes in their course of execution, such as genome annotation. However, more dynamism on the pipeline composition is necessary when each execution requires a different combination of steps. Results We propose a graph-based approach to implement extensible and low-maintenance pipelines that is suitable for pipeline applications with multiple functionalities that require different combinations of steps in each execution. Here pipelines are composed automatically by compiling a specialised set of tools on demand, depending on the functionality required, instead of specifying every sequence of tools in advance. We represent the connectivity of pipeline components with a directed graph in which components are the graph edges, their inputs and outputs are the graph nodes, and the paths through the graph are pipelines. To that end, we developed special data structures and a pipeline system algorithm. We demonstrate the applicability of our approach by implementing a format conversion pipeline for the fields of population genetics and genetic epidemiology, but our approach is also helpful in other fields where the use of multiple software is necessary to perform comprehensive analyses, such as gene expression and proteomics analyses. The project code, documentation and the Java executables are available under an open source license at http

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. A Wavelet-Based Approach to Fall Detection

    OpenAIRE

    Luca Palmerini; Fabio Bagalà; Andrea Zanetti; Jochen Klenk; Clemens Becker; Angelo Cappello

    2015-01-01

    Falls among older people are a widely documented public health problem. Automatic fall detection has recently gained huge importance because it could allow for the immediate communication of falls to medical assistance. The aim of this work is to present a novel wavelet-based approach to fall detection, focusing on the impact phase and using a dataset of real-world falls. Since recorded falls result in a non-stationary signal, a wavelet transform was chosen to examine fall patterns. The idea ...

  17. Block-based approach to modelling of granulated fertilizers' quality

    DEFF Research Database (Denmark)

    Kohonen, J.; Reinikainen, S. P.; Høskuldsson, Agnar

    2009-01-01

    Fertilizer manufacturing is a customer-driven industry, where the quality of a product is a key factor in order to survive the competition. However, measuring the most important feature with granulated fertilizers, flowability, is tedious, time-consuming and thus expensive. Flowability can...... to observe the different effect of the blocks on the modelling task. The present approach is based on priority PLS and multi-block PLS. The data is measured from the final product and is divided into blocks between physical properties, such as granule hardness and roundness, chemical composition and particle...

  18. Study of Face Recognition Approach Based on Similarity Measures

    Directory of Open Access Journals (Sweden)

    Noha Aboelwafa

    2012-09-01

    Full Text Available Detecting the similarity of face image aims to determine the image of a face for verification purpose of documents such as passport, driving license, ID cards, etc. A new approach for face recognition based on similarity measure method is introduced. In addition, We apply various measure classes to increase the efficiency of the proposed method. The properties, sensitivity and effectiveness of the proposed measures are investigated and tested on 400 images from the ORL face database. Experimental results show that these similarity measures can give an useful way for measuring the similarity between fuzzy sets.

  19. Control system of motivation of personal based on gradient approach

    Directory of Open Access Journals (Sweden)

    Doliatovskii Valerii Anastasievich

    2014-07-01

    Full Text Available The concept of management by motivation of workers on the basis of definition of sensitivity of results of work to influence various motives is proved. There by the object of management is identified by a set of indicators of sensitivity which are the limiting sizes defining reaction of workers on motives. By averaging of the given questionnaires the matrix of identification of system of motivation is received. On its basis the decision of direct and return problems of management is possible. Experimental data about results of application are led to a choice of system of motivation based on gradient the approach.

  20. 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...

  1. An RBF-PSO based approach for modeling prostate cancer

    Science.gov (United States)

    Perracchione, Emma; Stura, Ilaria

    2016-06-01

    Prostate cancer is one of the most common cancers in men; it grows slowly and it could be diagnosed in an early stage by dosing the Prostate Specific Antigen (PSA). However, a relapse after the primary therapy could arise in 25 - 30% of cases and different growth characteristics of the new tumor are observed. In order to get a better understanding of the phenomenon, a two parameters growth model is considered. To estimate the parameters values identifying the disease risk level a novel approach, based on combining Particle Swarm Optimization (PSO) with meshfree interpolation methods, is proposed.

  2. Statistically Based Approach to Broadband Liner Design and Assessment

    Science.gov (United States)

    Nark, Douglas M. (Inventor); Jones, Michael G. (Inventor)

    2016-01-01

    A broadband liner design optimization includes utilizing in-duct attenuation predictions with a statistical fan source model to obtain optimum impedance spectra over a number of flow conditions for one or more liner locations in a bypass duct. The predicted optimum impedance information is then used with acoustic liner modeling tools to design liners having impedance spectra that most closely match the predicted optimum values. Design selection is based on an acceptance criterion that provides the ability to apply increasing weighting to specific frequencies and/or operating conditions. One or more broadband design approaches are utilized to produce a broadband liner that targets a full range of frequencies and operating conditions.

  3. Scapular dyskinesia: evolution towards a systems-based approach.

    Science.gov (United States)

    Willmore, Elaine G; Smith, Michael J

    2016-01-01

    Historically, scapular dyskinesia has been used to describe an isolated clinical entity whereby an abnormality in positioning, movement or function of the scapula is present. Based upon this, treatment approaches have focused on addressing local isolated muscle activity. Recently, however, there has been a progressive move towards viewing the scapula as being part of a wider system of movement that is regulated and controlled by multiple factors, including the wider kinetic chain and individual patient-centred requirements. We therefore propose a paradigm shift whereby scapular dyskinesia is seen not in isolation but is considered within the broader context of patient-centred care and an entire neuromuscular system. PMID:27583003

  4. 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.

  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. Patient radiation exposure during coronary angiography and intervention

    Energy Technology Data Exchange (ETDEWEB)

    Fransson, S.G.; Persliden, J. [Univ. Hospital, Linkoeping (Sweden). Dept. of Thoracic Radiology

    2000-03-01

    Purpose: To prospectively register fluoroscopic and cine times in a random fashion, and to measure patient radiation exposure from routine coronary angiography and coronary balloon angioplasty. We also evaluated an optional dose reduction system used during interventions. Material and methods: The incident radiation to the patient was measured as kerma area product (KAP) in Gycm{sup 2}, obtained from an ionisation chamber mounted on the undercouch tube during 65 coronary angiography procedures and another 53 percutaneous transluminal coronary angioplasties, mostly directly following complete coronary angiography. Results and conclusion: The values from coronary angiography were comparable to other reports with a mean fluoroscopic time of 4.4 min and a mean KAP value of 62.6 Gy/cm{sup 2}. The corresponding figures from coronary balloon angioplasty without stenting were lower than otherwise reported, with 8.2 min and 47.9 Gycm{sup 2}, respectively. The use of coronary stents did prolong the mean fluoroscopic time (10.5 min) but did not significantlyenhance the patient mean radiation dose (51.4 Gycm{sup 2}). The dose reduction technique resulted in a significant KAP value reduction of 57%. In conclusion, with regard to radiation exposure, coronary angiography and balloon angioplasty are considered safe procedures.

  7. 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…

  8. 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.

  9. Systematic approach for synthesis of palm oil-based biorefinery

    Energy Technology Data Exchange (ETDEWEB)

    NG, Rex T. L.; NG, Denny K. S.; LAM, Hon Loong [Dept. of Chemical and Environmental Engineering, Centre of Excellence for Green Technologies, Univ. of Nottingham, Selangor, (Malaysia); TAY, Douglas H. S.; LIM, Joseph H. E. [2GGS Eco Solutions Sdn Bhd, Kuala Lumpur (Malaysia)

    2012-11-01

    Various types of palm oil biomasses are generated from palm oil mill when crude palm oil (CPO) is produced from fresh fruit bunch (FFB). In the current practice, palm oil biomasses are used as the main source of energy input in the palm oil mill to produce steam and electricity. Moreover, those biomasses are regarded as by-products and can be reclaimed easily. Therefore, there is a continuous increasing interest concerning biomasses generated from the palm oil mill as a source of renewable energy. Although various technologies have been exploited to produce bio-fuel (i.e., briquette, pellet, etc.) as well as heat and power generation, however, no systematic approach which can analyse and optimise the synthesise biorefinery is presented. In this work, a systematic approach for synthesis and optimisation of palm oil-based biorefinery which including palm oil mill and refinery with maximum economic performance is developed. The optimised network configuration with achieves the maximum economic performance can also be determined. To illustrate the proposed approach, a case study is solved in this work.

  10. 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.

  11. Individually optimized uniform contrast enhancement in CT angiography for the diagnosis of pulmonary thromboembolic disease—A simulation study

    International Nuclear Information System (INIS)

    Purpose: To improve the diagnostic quality of CT pulmonary angiography (CTPA) by individually optimizing a biphasic contrast injection function to achieve targeted uniform contrast enhancement. To compare the results against a previously reported discrete Fourier transform (DFT) approach. Methods: This simulation study used the CTPA datasets of 27 consecutive patients with pulmonary thromboembolic disease (PE). An optimization approach was developed consisting of (1) computation of the impulse enhancement function (IEF) based on a test bolus scan, and (2) optimization of a biphasic contrast injection function using the IEF in order to achieve targeted uniform enhancement. The injection rates and durations of a biphasic contrast injection function are optimized by minimizing the difference between the resulting contrast enhancement curve and the targeted uniform enhancement curve, while conforming to the clinical constraints of injection rate and total contrast volume. The total contrast volume was limited first to the clinical standard of 65 ml, and then to the same amount used in the DFT approach for comparison. The optimization approach and the DFT approach were compared in terms of the root mean square error (RMSE) and total contrast volume used. Results: When the total contrast volume was limited to 65 ml, the optimization approach produced significantly better contrast enhancement (closer to the targeted uniform contrast enhancement) than the DFT approach (RMSE 17 HU vs 56 HU,p < 0.00001). On average, the optimization approach used 63 ml contrast, while the DFT approach used 50 ml with four patients exceeding 65 ml. When equivalent total contrast volume was used for individual patient, the optimization approach still generated significantly better contrast enhancement (RMSE 44 HU vs 56 HU, p < 0.01). Constraints for the injection function could be easily accommodated into the optimization process when searching for the optimal biphasic injection function

  12. CT Angiography May Be a More Useful Modality Than Digital Subtractional Angiography in the Diagnosis of Patients with Subarachnoid Hemorrhage Due to Cerebral Aneurysms

    Directory of Open Access Journals (Sweden)

    Masih Saboori

    2011-05-01

    Full Text Available Background/Objective: The preoperative diagnostic"nvalidity of two radiological modalities (computed"ntomographic angiography and digital subtractional"nangiography in the diagnosis of brain aneurysms were"ncompared."nPatients and Methods: During 2 years of study,"nreferred patients with signs of SAH to the emergency"nward underwent routine CT scan and after SAH was"nfirmly diagnosed, CTA and DSA methods were done"nand patients with correct indications were operated."nAfter surgery and detecting the existence of aneurysms"nand their location, the data were recorded in a"nchecklist. Sensitivity, specificity, positive and negative"npredictive values were calculated and compared in"nboth methods."nResults: The mean age of the 30 patients were"n49.5±9.13 years. 57.9 % of the subjects were female"nand the others were male. On CTA reports 100% true"npositive, 0% false positive, 85% true negative, and 15%"nfalse negative were calculated. DSA reports were true"npositive, false positive, true negative and false negative"nin 100%, 0%, 69% and 31%, respectively. CTA showed"n89% of sensitivity, and 100% of specificity in contrast"nto 74% sensitivity and 100% specificity of DSA."nPositive predictive values of both methods were 100%,"nbut negative predictive values of CTA and DSA were"n85% and 69%, respectively."nConclusion: Based on our data, CTA is more preferable"ndiagnostic modality for the brain aneurysm's site and"nanatomy in patients with subarachnoid hemorrhage"nthan DSA."nKeywords: CT Scan Angiography, Digital Subtraction"nAngiography, Cerebral Aneurysm, Subarachnoid"nHemorrhage

  13. The competence-based didactic approach in initial vocational education

    Directory of Open Access Journals (Sweden)

    Skubic-Ermenc Klara

    2014-01-01

    Full Text Available This article examines a didactic and curricular model that was developed to support the implementation of a competence-based approach, today prevailing in the European (initial vocational education and training (VET. It starts by presenting contemporary developments in the Slovenian VET, and then continues with a study of some of the underlying pedagogical concepts influencing the contemporary educational practice. The concept of competence, as it relates to the Slovenian VET, is discussed, and the new didactic model is presented in terms of its conceptualisation, realisation and evaluation. The model is built around the concepts of the competence- based didactic unit, and has been produced to help teachers support students in developing the ability to integrate knowledge, skills and attitudes, so that they are able to solve complex and unpredictable professional tasks and challenges. The article concludes with a discussion on the methodological limitations of the evaluation, and its transferability to other contexts.

  14. 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.

  15. 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.

  16. 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...

  17. A New Design Approach to Game-Based learning

    DEFF Research Database (Denmark)

    Larsen, Lasse Juel

    2012-01-01

    This paper puts forward a new design perspective for gamebased learning. The general idea is to abandon the long sought-after dream of designing a closed learning system, where students in both primary and secondary school could learn – without the interference of teachers – whatever subject......-based learning system, but will also confront aspects of modern learning theory, especially the notion of reference between the content of an assignment and the reality with which it should or could be connected (situated learning). The second idea promotes a way of tackling the common experience of the average...... to ground the student’s reason to learn. This paper proposes a different approach: using visualisation in immersive 3D worlds as both documentation of learning progress and as a reward system which motivates further learning. The overall design idea is to build a game based learning system from three...

  18. Improving information extraction using a probability-based approach

    DEFF Research Database (Denmark)

    Kim, S.; Ahmed, Saeema; Wallace, K.

    2007-01-01

    . It would be helpful to compile a full list of entities associated with the relevant types before identifying them in texts. However, due to the various ways of referring entities in the texts, manually defined identification rules tend to produce high precision but with low recall. In order to increase...... that these searches often prove unsuccessful. Searches can be improved if domain entities of interest, e.g., 'gas turbine; are explicitly associated with their types, i.e., gas turbine is a type of engine, thus reducing the ambiguity of referring to the entities using various different ways of expressing them...... the recall, while maintaining the high precision, a learning approach that makes identification decisions based on a probability model, rather than simply looking up the presence of the pre-defined variations, looks promising. This paper presents the results of developing such a probability-based entity...

  19. 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.

  20. Copula-Based Approach to Synthetic Population Generation.

    Science.gov (United States)

    Jeong, Byungduk; Lee, Wonjoon; Kim, Deok-Soo; Shin, Hayong

    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