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Sample records for angiography based approach

  1. Rotational Angiography Based Three-Dimensional Left Atrial Reconstruction: A New Approach for Transseptal Puncture.

    Science.gov (United States)

    Koektuerk, Buelent; Yorgun, Hikmet; Koektuerk, Oezlem; Turan, Cem H; Gorr, Eduard; Horlitz, Marc; Turan, Ramazan G

    2016-02-01

    Rotational angiography is a well-known method for the three-dimensional (3-D) reconstruction of left atrium and pulmonary veins during left-sided atrial arrhythmia ablation procedures. In our study, we aimed to review our experience in transseptal puncture (TSP) using 3-D rotational angiography. We included a total of 271 patients who underwent atrial fibrillation ablation using cryoballoon. Rotational angiography was performed to get the three-dimensional left atrial and pulmonary vein reconstructions using cardiac C-arm computed tomography. The image reconstruction was made using the DynaCT Cardiac software (Siemens, Erlangen, Germany). The mean age of the study population was 61 ± 10 years. The indications for left atrial arrhythmia ablation were paroxysmal AF in 140 patients (52%) and persistent AF patients in 131 (48%) patients. The success rate of TSP using only rotational guidance was (264/271 patients, 97.4%). In the remaining seven patients, transesophageal guidance was used after the initial attempt due to thick interatrial septum in five patients and difficult TSP due to abnormal anatomy and mild pericardial effusion in the remaining two patients. Mean fluoroscopy dosage of the rotational angiography was 4896.4 ± 825.3 μGym(2). The mean time beginning from femoral vein puncture to TSP was 12.3 ± 5.5 min. TSP guided by rotational angiography is a safe and effective method. Our results indicate that integration of rotational angiographic images into the real-time fluoroscopy can guide the TSP during the procedure. © 2015 John Wiley & Sons Ltd.

  2. Angiography

    International Nuclear Information System (INIS)

    Grinnell, V.S.; Mehringer, C.M.; Hieshima, G.B.

    1987-01-01

    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

  3. Infrared-laser-based fundus angiography

    Science.gov (United States)

    Klingbeil, Ulrich; Canter, Joseph M.; Lesiecki, Michael L.; Reichel, Elias

    1994-06-01

    Infrared fundus angiography, using the fluorescent dye indocyanine green (ICG), has shown great potential in delineating choroidal neovascularization (CNV) otherwise not detectable. A digital retinal imaging system containing a diode laser for illumination has been developed and optimized to perform high sensitivity ICG angiography. The system requires less power and generates less pseudo-fluorescence background than nonlaser devices. During clinical evaluation at three retinal centers more than 200 patients, the majority of which had age-related macular degeneration, were analyzed. Laser based ICG angiography was successful in outlining many of the ill-defined or obscure CNV as defined by fluorescein angiography. The procedure was not as successful with classic CNV. ICG angiograms were used to prepare and guide laser treatment.

  4. Transbrachial artery approach for selective cerebral angiography

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

    1990-02-01

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

  5. The transradial approach for selective carotid and vertebral angiography

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    Iwasaki, S.; Ueda, K.; Sueyosi, S.; Nagasawa, M.; Ude, K. [Higashiosaka City General Hospital, Osaka (Japan). Dept. of Radiology; Yokoyama, K. [Higashiosaka City General Hospital, Osaka (Japan). Dept. of Neurosurgery; Takayama, K.; Nakagawa, H.; Kichikawa, K. [Nara Medical Univ., Osaka (Japan). Dept. of Radiology

    2002-11-01

    Purpose: The transradial approach is not so popular in cerebral angiography. The purpose of this study was therefore to present our experience of success rate and safety of this method. Material and Methods: From December 1998 to June 2001, 526 carotid and vertebral angiographies with DSA were performed via the radial artery. A 1.4-mm catheter was used through a 1.4-mm introducer sheath. We evaluated the procedure as successful if sufficient images for diagnosis were obtained of the bilateral carotid arteries and unilateral vertebral artery. Each patient was reassessed for any complications, occurring until the next morning. The length of time needed for an examination was measured in the last 10 cases. Results: In all but 5 cases, the procedures were evaluated as successful (99.0%). Unsuccessful cases manifested severe pain at the radial puncture, angiospasm at the radial artery, loop formation at the radial artery, occlusion at the subclavian artery, and an aberrant right subclavian artery. No severe complications including neurological ones were encountered. Minor complications were noted in 17 cases (3.2%): 4 cases of thrombus at the ulnar artery, 1 angiospasm at the radial artery, and 12 cases of small hematoma at the puncture site. The radial approach took 14 min less in the common carotid study and 3 min 30 s less in the internal carotid study than by the femoral approach. Conclusion: The transradial approach enabled selective studies for carotid and vertebral angiography with a high success rate and safety with few complications.

  6. The transradial approach for selective carotid and vertebral angiography

    International Nuclear Information System (INIS)

    Iwasaki, S.; Ueda, K.; Sueyosi, S.; Nagasawa, M.; Ude, K.; Yokoyama, K.; Takayama, K.; Nakagawa, H.; Kichikawa, K.

    2002-01-01

    Purpose: The transradial approach is not so popular in cerebral angiography. The purpose of this study was therefore to present our experience of success rate and safety of this method. Material and Methods: From December 1998 to June 2001, 526 carotid and vertebral angiographies with DSA were performed via the radial artery. A 1.4-mm catheter was used through a 1.4-mm introducer sheath. We evaluated the procedure as successful if sufficient images for diagnosis were obtained of the bilateral carotid arteries and unilateral vertebral artery. Each patient was reassessed for any complications, occurring until the next morning. The length of time needed for an examination was measured in the last 10 cases. Results: In all but 5 cases, the procedures were evaluated as successful (99.0%). Unsuccessful cases manifested severe pain at the radial puncture, angiospasm at the radial artery, loop formation at the radial artery, occlusion at the subclavian artery, and an aberrant right subclavian artery. No severe complications including neurological ones were encountered. Minor complications were noted in 17 cases (3.2%): 4 cases of thrombus at the ulnar artery, 1 angiospasm at the radial artery, and 12 cases of small hematoma at the puncture site. The radial approach took 14 min less in the common carotid study and 3 min 30 s less in the internal carotid study than by the femoral approach. Conclusion: The transradial approach enabled selective studies for carotid and vertebral angiography with a high success rate and safety with few complications

  7. Bolus characteristics based on Magnetic Resonance Angiography

    Directory of Open Access Journals (Sweden)

    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.

  8. [A digital subtraction angiography system based on LUT algorithms].

    Science.gov (United States)

    Chen, Xiangan; Li, Kaiyang; Zhou, Li; Chen, Jiansheng

    2006-04-01

    Look-up table (LUT) algorithms have been widely used in digital signal processing, but the article on the application of LUT algorithms in digital subtraction angiography was rarely reported. In this article, the effect of different LUT algorithms on digital subtraction angiography images is introduced. The result reveals that different LUT algorithms can bring about different effects of image. Based on analysis and comparison, we deem it possible to acquire improved images of DSA by use of some LUT algorithms with image processing.

  9. Optical coherence tomography angiography-based capillary velocimetry

    Science.gov (United States)

    Wang, Ruikang K.; Zhang, Qinqin; Li, Yuandong; Song, Shaozhen

    2017-06-01

    Challenge persists in the field of optical coherence tomography (OCT) when it is required to quantify capillary blood flow within tissue beds in vivo. We propose a useful approach to statistically estimate the mean capillary flow velocity using a model-based statistical method of eigendecomposition (ED) analysis of the complex OCT signals obtained with the OCT angiography (OCTA) scanning protocol. ED-based analysis is achieved by the covariance matrix of the ensemble complex OCT signals, upon which the eigenvalues and eigenvectors that represent the subsets of the signal makeup are calculated. From this analysis, the signals due to moving particles can be isolated by employing an adaptive regression filter to remove the eigencomponents that represent static tissue signals. The mean frequency (MF) of moving particles can be estimated by the first lag-one autocorrelation of the corresponding eigenvectors. Three important parameters are introduced, including the blood flow signal power representing the presence of blood flow (i.e., OCTA signals), the MF indicating the mean velocity of blood flow, and the frequency bandwidth describing the temporal flow heterogeneity within a scanned tissue volume. The proposed approach is tested using scattering phantoms, in which microfluidic channels are used to simulate the functional capillary vessels that are perfused with the scattering intralipid solution. The results indicate a linear relationship between the MF and mean flow velocity. In vivo animal experiments are also conducted by imaging mouse brain with distal middle cerebral artery ligation to test the capability of the method to image the changes in capillary flows in response to an ischemic insult, demonstrating the practical usefulness of the proposed method for providing important quantifiable information about capillary tissue beds in the investigations of neurological conditions in vivo.

  10. Catheter Angiography

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    Full Text Available ... News Physician Resources Professions Site Index A-Z Catheter Angiography Catheter angiography uses a catheter, x-ray ... are the limitations of Catheter Angiography? What is Catheter Angiography? Angiography is a minimally invasive medical test ...

  11. Three dimensional quantitative coronary angiography can detect reliably ischemic coronary lesions based on fractional flow reserve.

    Science.gov (United States)

    Chung, Woo-Young; Choi, Byoung-Joo; Lim, Seong-Hoon; Matsuo, Yoshiki; Lennon, Ryan J; Gulati, Rajiv; Sandhu, Gurpreet S; Holmes, David R; Rihal, Charanjit S; Lerman, Amir

    2015-06-01

    Conventional coronary angiography (CAG) has limitations in evaluating lesions producing ischemia. Three dimensional quantitative coronary angiography (3D-QCA) shows reconstructed images of CAG using computer based algorithm, the Cardio-op B system (Paieon Medical, Rosh Ha'ayin, Israel). The aim of this study was to evaluate whether 3D-QCA can reliably predict ischemia assessed by myocardial fractional flow reserve (FFR) < 0.80. 3D-QCA images were reconstructed from CAG which also were evaluated with FFR to assess ischemia. Minimal luminal diameter (MLD), percent diameter stenosis (%DS), minimal luminal area (MLA), and percent area stenosis (%AS) were obtained. The results of 3D-QCA and FFR were compared. A total of 266 patients was enrolled for the present study. FFR for all lesions ranged from 0.57 to 1.00 (0.85 ± 0.09). Measurement of MLD, %DS, MLA, and %AS all were significantly correlated with FFR (r = 0.569, 0609, 0.569, 0.670, respectively, all P < 0.001). In lesions with MLA < 4.0 mm(2), %AS of more than 65.5% had a 80% sensitivity and a 83% specificity to predict FFR < 0.80 (area under curve, AUC was 0.878). 3D-QCA can reliably predict coronary lesions producing ischemia and may be used to guide therapeutic approach for coronary artery disease.

  12. Comparison of radiation exposure during transradial diagnostic coronary angiography with single- or multi-catheters approach.

    Science.gov (United States)

    Plourde, Guillaume; Abdelaal, Eltigani; MacHaalany, Jimmy; Rimac, Goran; Poirier, Yann; Arsenault, Jean; Costerousse, Olivier; Bertrand, Olivier F

    2017-08-01

    To compare radiation exposure during transradial diagnostic coronary angiography (DCA) using standard single- or multi-catheters with different shapes. Transradial DCA can be performed using single- or multi-catheters to canulate left and right coronary ostia. To date, it remains unknown whether there are differences in radiation exposure between the two strategies. From November 2012 to June 2014, 3,410 consecutive patients who underwent transradial DCA were recruited. Groups were based on the initial diagnostic catheter used and were dichotomized between single- and multi-catheters approach. All crossovers were excluded. The multi-catheters approach (Multi) group consisted of Judkins left and right catheters, whereas the single-catheter (Single) group included Amplatz, Barbeau, or Multipurpose catheters. Fluoroscopy time (FT) as a surrogate end-point for total radiation exposure and kerma-area product (KAP; patient radiation exposure) were collected as radiation exposure parameters. A single-catheter strategy was used in 439 patients, while 2,971 patients had a multi-catheters approach. There was no significant difference in FT between groups (2.86 ± 1.48 min for Multi vs. 2.87 ± 1.72 min for Single, P = 0.13). The multi-catheters approach was associated with a significant 15% reduction in KAP (3,599 ± 2,214 cGy · cm 2 vs. 3,073 ± 1,785 cGy · cm 2 , P approach. When pooling all patients, mean FT was 2.86 ± 1.51 min. Mean KAP was 3,141 ± 1,854 cGy · cm 2 . Reference levels in our institution in both groups were below international diagnostic reference levels. Overall both FT and KAP decreased by 15% and 19%, respectively, over the 2-year study period. Compared to a single-catheter approach, a multi-catheters approach with standard Judkins catheters for DCA significantly reduced patient radiation exposure. Whether single catheter designed for DCA by radial approach can further reduce radiation exposure compared to

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

    International Nuclear Information System (INIS)

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

    1987-01-01

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

  14. Catheter Angiography

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    Full Text Available ... Angiography is performed using: x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) In catheter angiography, ... a tumor; this is called superselective angiography. Unlike computed tomography (CT) or magnetic resonance (MR) angiography , use of ...

  15. "No zone" approach in penetrating neck trauma reduces unnecessary computed tomography angiography and negative explorations.

    Science.gov (United States)

    Ibraheem, Kareem; Khan, Muhammad; Rhee, Peter; Azim, Asad; O'Keeffe, Terence; Tang, Andrew; Kulvatunyou, Narong; Joseph, Bellal

    2018-01-01

    The most recent management guidelines advocate computed tomography angiography (CTA) for any suspected vascular or aero-digestive injuries in all zones and give zone II injuries special consideration. We hypothesized that physical examination can safely guide CTA use in a "no zone" approach. An 8-year retrospective analysis of all adult trauma patients with penetrating neck trauma (PNT) was performed. We included all patients in whom the platysma was violated. Patients were classified into three groups as follows: hard signs, soft signs, and asymptomatic. CTA use, positive CTA (contrast extravasation, dissection, or intimal flap) and operative details were reported. Primary outcomes were positive CTA and therapeutic neck exploration (TNE) (defined by repair of major vascular or aero-digestive injuries). A total of 337 patients with PNT met the inclusion criteria. Eighty-two patients had hard signs and all of them went to the operating room, of which 59 (72%) had TNE. One hundred fifty-six patients had soft signs, of which CTA was performed in 121 (78%), with positive findings in 12 (10%) patients. The remaining 35 (22%) underwent initial neck exploration, of which 14 (40%) were therapeutic yielding a high rate of negative exploration. Ninty-nine patients were asymptomatic, of which CTA was performed in 79 (80%), with positive findings in 3 (4%), however, none of these patients required TNE. On sub analysis based on symptoms, there was no difference in the rate of TNE between the neck zones in patients with hard signs (P = 0.23) or soft signs (P = 0.51). Regardless of the zone of injury, asymptomatic patients did not require a TNE. Physical examination regardless of the zone of injury should be the primary guide to CTA or TNE in patients with PNT. Following traditional zone-based guidelines can result in unnecessary negative explorations in patients with soft signs and may need rethinking. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Synchrotron-based intravenous cerebral angiography in a small animal model

    International Nuclear Information System (INIS)

    Kelly, Michael E; Schueltke, Elisabeth; Fiedler, Stephan; Nemoz, Christian; Guzman, Raphael; Corde, Stephanie; Esteve, Francois; LeDuc, Geraldine; Juurlink, Bernhard H J; Meguro, Kotoo

    2007-01-01

    K-edge digital subtraction angiography (KEDSA), a recently developed synchrotron-based technique, utilizes monochromatic radiation and allows acquisition of high-quality angiography images after intravenous administration of contrast agent. We tested KEDSA for its suitability for intravenous cerebral angiography in an animal model. Adult male New Zealand rabbits were subjected to either angiography with conventional x-ray equipment or synchrotron-based intravenous KEDSA, using an iodine-based contrast agent. Angiography with conventional x-ray equipment after intra-arterial administration of contrast agent demonstrated the major intracranial vessels but no smaller branches. KEDSA was able to visualize the major intracranial vessels as well as smaller branches in both radiography mode (planar images) and tomography mode. Visualization was achieved with as little as 0.5 ml kg -1 of iodinated contrast material. We were able to obtain excellent visualization of the cerebral vasculature in an animal model using intravenous injection of contrast material, using synchrotron-based KEDSA

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

    International Nuclear Information System (INIS)

    Rautio, R.; Keski-Nisula, L.; Paakkala, T.

    2003-01-01

    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.)

  18. Novel fluorescein angiography-based computer-aided algorithm for assessment of retinal vessel permeability.

    Directory of Open Access Journals (Sweden)

    Yonatan Serlin

    Full Text Available PURPOSE: To present a novel method for quantitative assessment of retinal vessel permeability using a fluorescein angiography-based computer algorithm. METHODS: Twenty-one subjects (13 with diabetic retinopathy, 8 healthy volunteers underwent fluorescein angiography (FA. Image pre-processing included removal of non-retinal and noisy images and registration to achieve spatial and temporal pixel-based analysis. Permeability was assessed for each pixel by computing intensity kinetics normalized to arterial values. A linear curve was fitted and the slope value was assigned, color-coded and displayed. The initial FA studies and the computed permeability maps were interpreted in a masked and randomized manner by three experienced ophthalmologists for statistical validation of diagnosis accuracy and efficacy. RESULTS: Permeability maps were successfully generated for all subjects. For healthy volunteers permeability values showed a normal distribution with a comparable range between subjects. Based on the mean cumulative histogram for the healthy population a threshold (99.5% for pathological permeability was determined. Clear differences were found between patients and healthy subjects in the number and spatial distribution of pixels with pathological vascular leakage. The computed maps improved the discrimination between patients and healthy subjects, achieved sensitivity and specificity of 0.974 and 0.833 respectively, and significantly improved the consensus among raters for the localization of pathological regions. CONCLUSION: The new algorithm allows quantification of retinal vessel permeability and provides objective, more sensitive and accurate evaluation than the present subjective clinical diagnosis. Future studies with a larger patients' cohort and different retinal pathologies are awaited to further validate this new approach and its role in diagnosis and treatment follow-up. Successful evaluation of vasculature permeability may be used for

  19. Catheter Angiography

    Medline Plus

    Full Text Available ... using: x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) In catheter angiography, a thin ... called superselective angiography. Unlike computed tomography (CT) or magnetic resonance (MR) angiography , use of a catheter makes ...

  20. Catheter Angiography

    Medline Plus

    Full Text Available ... x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) In catheter angiography, a thin plastic ... superselective angiography. Unlike computed tomography (CT) or magnetic resonance (MR) angiography , use of a catheter makes it ...

  1. Catheter Angiography

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    Full Text Available ... risks? What are the limitations of Catheter Angiography? What is Catheter Angiography? Angiography is a minimally invasive ... of ionizing radiation ( x-rays ). top of page What are some common uses of the procedure? Catheter ...

  2. Improving visualization of intracranial arteries at the skull base for CT angiography with calcified plaques

    Science.gov (United States)

    Huang, Adam; Lee, Chung-Wei; Yang, Chung-Yi; Liu, Hon-Man

    2010-03-01

    Bony structures at the skull base were the main obstacle to detection and estimation of arterial stenoses and aneurysms for CT angiography in the brain. Direct subtraction and the matched mask bone elimination (MMBE) have become two standard methods for removing bony structures. However, clinicians regularly find that calcified plaques at or near the carotid canal cannot be removed satisfactorily by existing methods. The blood-plaque boundary tends to be blurred by subtraction operation while plaque size is constantly overestimated by the bone mask dilation operation in the MMBE approach. In this study, we propose using the level of enhancement to adjust the MMBE bone mask more intelligently on the artery- and tissue-bone/plaque boundaries. The original MMBE method is only applied to the tissue-bone boundary voxels; while the artery-bone/blood-plaque boundary voxels, identified by a higher enhancement level, are processed by direct subtraction instead. A dataset of 6 patients (3 scanned with a regular dose and 3 scanned with a reduced dose) with calcified plaques at or near the skull base is used to examine our new method. Preliminary results indicate that the visualization of intracranial arteries with calcified plaques at the skull base can be improved effectively and efficiently.

  3. 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.

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

    Science.gov (United States)

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

    2011-03-21

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

  5. 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.

  6. Retrospective analysis of patients for development of nephrogenic systemic fibrosis following conventional angiography using gadolinium-based contrast agents

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, Hanno; Spagnuolo, Sara; Froehlich, Johannes M.; Thoeny, Harriet C. [University Hospital Bern, Institute of Diagnostic, Interventional, and Pediatric Radiology, Inselspital, Bern (Switzerland); Nievergelt, Helga [University Hospital Bern, Clinic of Dermatology, Bern (Switzerland); Dinkel, Hans-Peter [Hospital Landshut, Institute of Diagnostic and Interventional Radiology, Landshut (Germany); Gretener, Silvia [University Hospital of Bern, Division of Vascular Medicine, Swiss Cardiovascular Center, Bern (Switzerland)

    2010-03-15

    The purpose was to retrospectively review the data of 27 patients with renal insufficiency who underwent conventional angiography with gadolinium-based contrast agents (GDBCA) as alternative contrast agents and assess the occurrence of nephrogenic systemic fibrosis (NSF) together with associated potential risk factors. This HIPAA-compliant study had institutional review board approval, and informed consent was waived. Statistical analysis was performed for all available laboratory and clinical data, including dermatology reports. Type and amount of the GDBCA used were recorded for angiography and additional MRI studies, if applicable. Serum creatinine levels (SCr) pre- and post-angiography were recorded, and estimated glomerular filtration rates (eGFR) were calculated. Ten female and 17 male patients who underwent angiography with GDBCA were included. The mean amount of GDBCA administered was 44 {+-} 15.5 ml (range 15-60 ml) or 0.24 + 0.12 mmol/kg (range 0.1-0.53 mmol/kg). At the time of angiography all patients had renal insufficiency (eGFR <60 ml/min/1.73 m{sup 2}). Mean eGFR pre-angiography was 26 ml/min/1.73 m{sup 2} and 33 ml/min/1.73 m{sup 2} post-angiography. The mean follow-up period covers 28 months, range 1-84 months. Additional MRI studies with GDBCA administration were performed in 15 patients. One patient with typical skin lesions had developed biopsy-confirmed NSF. Conventional arterial angiography with GDBCA may play a role in the development of NSF in patients with renal insufficiency. Alternative contrast agents, such as CO{sub 2} angiography or rather the use of low doses of iodinated contrast agents, should be considered in these patients. (orig.)

  7. Abdominal MR angiography

    International Nuclear Information System (INIS)

    Wegmueller, H.; Vock, P.

    1993-01-01

    The two techniques currently most often used for MR angiography, those based on time-of-flight effects and on phase-contrast, are introduced, and our results with three-dimensional phase contrast angiography of the abdomen are presented. Several basic differences from other imaging procedures render MR angiography clinically useful for screening for renal artery stenosis in critical situations, such as renal failure or intolerance to contrast agents. In the future, the spectrum of applications of MR angiography will broaden and include other indications, such as portal venous hypertension and follow-up studies after surgical portal systemic shunting. (orig.) [de

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Catheter Angiography

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    Full Text Available ... Videos About Us News Physician Resources Professions Site Index A-Z Catheter Angiography Catheter angiography uses a ... few millimeters) in the skin where the catheter can be inserted into an artery. The catheter is ...

  10. Catheter Angiography

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    Full Text Available ... story about radiology? Share your patient story here Images × Image Gallery Interventional radiologist performing an angiography exam View ... ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Catheter Angiography Sponsored by Please note ...

  11. Catheter Angiography

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    Full Text Available ... you are pregnant and discuss any recent illnesses, medical conditions, medications you're taking and allergies, especially ... is Catheter Angiography? Angiography is a minimally invasive medical test that helps physicians diagnose and treat medical ...

  12. Catheter Angiography

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    Full Text Available ... angiography exam View full size with caption Related Articles and Media Angioplasty and Vascular Stenting MR Angiography ( ... facilities database . This website does not provide cost information. The costs for specific medical imaging tests, treatments ...

  13. Catheter Angiography

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    Full Text Available ... resonance imaging (MRI) In catheter angiography, a thin plastic tube, called a catheter , is inserted into an ... The catheter used in angiography is a long plastic tube about as thick as a strand of ...

  14. Catheter Angiography

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    Full Text Available ... Z Catheter Angiography Catheter angiography uses a catheter, x-ray imaging guidance and an injection of contrast material ... vessels in the body. Angiography is performed using: x-rays with catheters computed tomography (CT) magnetic resonance imaging ( ...

  15. Three-dimensional computed tomography angiography of the galenic system for the occipital transtentorial approach

    International Nuclear Information System (INIS)

    Suzuki, Yasuhiro; Nakajima, Masateru; Ikeda, Hisato; Abe, Takumi

    2005-01-01

    The venous variations of the galenic system were evaluated using three-dimensional computed tomography angiography (3D-CTA) to assess the influence on the occipital transtentorial approach in 150 patients who underwent 3D-CTA as a routine screening examination for cerebrovascular diseases. The variations of the vein of Galen with its tributaries, the tentorial sinus, and the veins around the tentorium were evaluated in multiple intensity projections and stereoscopic images. The angle between the vein of Galen and the straight sinus was 67.1±31.9 deg (mean±SD). Observation of the pineal body from the direction of the approach tended to extend to the quadrigeminal bodies in acute angle cases, and to the third ventricle in obtuse angle cases. Bilateral internal cerebral veins (ICVs) joined in the anterior portion were associated with a long vein of Galen, or in the posterior portion with a short vein of Galen. The distance between the bilateral ICVs was 4.66±2.28 mm (mean±SD), and the shape of the space could be classified as spindle, parallel, hairpin, and round types. The basal vein could be classified into well-developed, hypoplastic, hardly recognized, and mimicking two basal veins because the tributary did not join but ran parallel to the basal vein. The drainage pathways lead to the anterior or posterior portion of the vein of Galen, the ICV, the tentorial sinus, and the superior petrosal sinus. The various types of the tentorial sinus and primitive tentorial sinus which might be sacrificed during section of the tentorium were confirmed. The inferior cerebral vein draining to the tentorial sinus could be seen. 3D-CTA could also demonstrate the presence, the course, and the drainage points of the internal occipital vein, the precentral cerebellar vein, the posterior pericallosal vein, and so on. 3D-CTA is useful to evaluate the variations of the venous system and the relationship with the tumor, and for preoperative simulation and intraoperative navigation of

  16. Real time OCT-based angiography device with hand-held probe (Conference Presentation)

    Science.gov (United States)

    Moiseev, Alexander A.; Gelikonov, Grigory V.; Ksenofontov, Sergey Y.; Gelikonov, Valentin M.; Matveev, Lev A.; Zaitsev, Vladimir Y.; Matveev, Alexander L.; Sirotkina, Marina A.; Gladkova, Natalia D.; Vitkin, I. Alex

    2017-02-01

    This work is dedicated to development of the OCT system with angiography for everyday clinical use. Two major problems were solved during the development: compensation of specific tissue displacements, induced by contact scanning mode and physiological motion of patients (e.g. respiratory and cardiac motions) and on-line visualization of vessel net, to provide the feedback for system operator. The performance of the resulting OCT-based microangiography device with hand-held probe was evaluated by visualization of vessels nets of volunteers oral mucosa and skin on different locations (hands, face, abdomen etc.). Success-rate more than 90% was demonstrated during the experiments.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-08-15

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

  18. Digital subtraction angiography - a new approach to brain death determination in the newborn

    International Nuclear Information System (INIS)

    Albertini, A.; Schonfeld, S.; Hiatt, M.; Hegyi, T.

    1993-01-01

    The diagnosis of brain death in the newborn infants is elusive and often difficult. The lack of cerebral blood flow has become an identified criterion for loss of cerebral function. The diagnosis can be obtained by the technique of digital subtraction angiography, which is presented in two case reports demonstrating the utility of this technique. (orig.)

  19. Pediatric angiography

    International Nuclear Information System (INIS)

    Fitz, A.R.

    1987-01-01

    Angiography of the cerebral and visceral arterial systems is performed much less frequently than it was before the advent of computed tomographic scanning (CT). Most institutions have experienced at least a 50% reduction in the number of angiograms performed since installing a CT scanner. However, angiography still plays an important role in the confirmation of diagnoses made using a scanner, and in providing valuable information to the surgeon prior to excision of tumors or the repair of traumatized organs. Recently a number of sophisticated therapeutic procedures requiring vascular catheterization and the injection of contrast agents have been developed. In these procedures catheters are selectively placed in blood vessels perfusing a pathological process, such as an arteriovenous malformation, or at the site of an arterial stenosis; embolization of the arteriovenous malformation or tumor, or dilatation of the stenotic segment, is then performed. Whether the vessel catheterization is for diagnostic or therapeutic purposes, the basic approach is the same, and the technologist's duties are similar. The principal difference between a diagnostic and a therapeutic procedure is the length of time required to carry out the study; therapeutic procedures often require significantly longer periods of general anesthesia or sedation than do diagnostic studies

  20. 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

  1. Catheter Angiography

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Catheter Angiography Catheter angiography ...

  2. Catheter Angiography

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    Full Text Available ... imaging technologies and, in most cases, a contrast material injection is needed to produce pictures of blood vessels in the body. Angiography is performed using: x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) In catheter angiography, a thin ...

  3. Catheter Angiography

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    Full Text Available ... further information please consult the ACR Manual on Contrast Media and its references. The risk of serious allergic ... View full size with caption Related Articles and Media Angioplasty and Vascular Stenting MR Angiography (MRA) Contrast Materials CT Angiography (CTA) X-ray, Interventional Radiology ...

  4. Catheter Angiography

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

  5. [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.

  6. Understanding Angiography-Based Aneurysm Flow Fields through Comparison with Computational Fluid Dynamics.

    Science.gov (United States)

    Cebral, J R; Mut, F; Chung, B J; Spelle, L; Moret, J; van Nijnatten, F; Ruijters, D

    2017-06-01

    Hemodynamics is thought to be an important factor for aneurysm progression and rupture. Our aim was to evaluate whether flow fields reconstructed from dynamic angiography data can be used to realistically represent the main flow structures in intracranial aneurysms. DSA-based flow reconstructions, obtained during interventional treatment, were compared qualitatively with flow fields obtained from patient-specific computational fluid dynamics models and quantitatively with projections of the computational fluid dynamics fields (by computing a directional similarity of the vector fields) in 15 cerebral aneurysms. The average similarity between the DSA and the projected computational fluid dynamics flow fields was 78% in the parent artery, while it was only 30% in the aneurysm region. Qualitatively, both the DSA and projected computational fluid dynamics flow fields captured the location of the inflow jet, the main vortex structure, the intrasaccular flow split, and the main rotation direction in approximately 60% of the cases. Several factors affect the reconstruction of 2D flow fields from dynamic angiography sequences. The most important factors are the 3-dimensionality of the intrasaccular flow patterns and inflow jets, the alignment of the main vortex structure with the line of sight, the overlapping of surrounding vessels, and possibly frame rate undersampling. Flow visualization with DSA from >1 projection is required for understanding of the 3D intrasaccular flow patterns. Although these DSA-based flow quantification techniques do not capture swirling or secondary flows in the parent artery, they still provide a good representation of the mean axial flow and the corresponding flow rate. © 2017 by American Journal of Neuroradiology.

  7. Simulation-based education leads to decreased use of fluoroscopy in diagnostic coronary angiography.

    Science.gov (United States)

    Prenner, Stuart B; Wayne, Diane B; Sweis, Ranya N; Cohen, Elaine R; Feinglass, Joe M; Schimmel, Daniel R

    2017-08-02

    The aim of this study is to determine whether simulation-based education (SBE) translates into reduced procedure time, radiation, and contrast use in actual clinical care. As a high volume procedure often performed by novice cardiology fellows, diagnostic coronary angiography represents an excellent target for SBE. Reports of SBE in interventional cardiology are limited and there is little understanding of the potential downstream clinical impact of these interventions. All diagnostic coronary angiograms performed at a single center between January 1, 2011 and June 30, 2015 were analyzed. Random effects linear regression models were used to compare outcomes between procedures performed by 12 cardiology fellows who underwent simulation-based training and those performed by 20 traditionally trained fellows. Thirty-two cardiology fellows performed 2,783 diagnostic coronary angiograms. Procedures performed by fellows trained with SBE were shorter (mean of 23.98 min vs. 24.94 min, P = 0.034) and were performed with decreased radiation (mean of 56,348 mGycm 2 vs. 66,120 mGycm 2 , P < 0.001). After controlling for year in training, procedure year, access site, and supervising attending physician, training on the simulator was independently associated with 117 fewer seconds of fluoroscopy time per procedure (P = 0.04). Diagnostic coronary angiography SBE is associated with decreased use of fluoroscopy in downstream clinical care. SBE may be a useful tool to reduce radiation exposure in the cardiac catheterization laboratory. © 2017 Wiley Periodicals, Inc.

  8. 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.)

  9. Computed Tomographic Angiography-Based Planning of Bipedicled DIEP Flaps with Intraflap Crossover Anastomosis: An Anatomical and Clinical Study.

    Science.gov (United States)

    Kim, So Young; Lee, Kyeong-Tae; Mun, Goo-Hyun

    2016-09-01

    When using deep inferior epigastric artery perforator (DIEP) flaps in breast reconstruction, harvesting bipedicled flaps can be a valuable option in cases requiring the transfer of a large portion of harvested flaps. Connecting the bilateral deep inferior epigastric arteries (DIEAs) by intraflap crossover anastomosis is one of the most popular methods of constructing bipedicled DIEP flaps. Planning the primary and secondary pedicle configurations for reliable intraflap crossover anastomosis is crucial. To achieve this, detailed anatomical DIEA information might be helpful. However, meticulous planning of bipedicled DIEP flaps based on computed tomographic angiography has not been reported. Detailed anatomical investigation of DIEA branches was conducted using computed tomographic angiographs of 100 hemiabdomens. Thirty-eight prospectively collected patients who underwent breast reconstruction using bipedicled DIEP flaps with intraflap crossover under computed tomographic angiography-based planning were reviewed. Three intramuscular DIEA branching patterns with distinct branch point topography, branch diameters, and superior continuations cranial to sizable perforators were observed. In the prospective clinical study, a primary pedicle with a recipient branch for intraflap crossover anastomosis could be specified preoperatively using computed tomographic angiography-based anatomical data of the pedicles, including size of DIEA branches or their superior continuation and size of perforators. In all cases, the bipedicle configuration was easily achieved as planned on computed tomographic angiography, and secure perfusion of the entire flap was achieved. The authors' results suggest that computed tomographic angiography provides detailed anatomical DIEA information, and comprehensive analysis of these data allows precise planning of bipedicle configurations with intraflap crossover anastomosis in DIEP flaps. Therapeutic, IV.

  10. Novel Approaches for the Use of Cardiac/Coronary Computed Tomography Angiography

    Directory of Open Access Journals (Sweden)

    Hadi Mirhedayati Roudsari, MD

    2016-12-01

    Full Text Available Recent developments in the novel imaging technology of cardiac computed tomography (CT not only permit detailed assessment of cardiac anatomy but also provide insight into cardiovascular physiology. Foremost, coronary CT angiography (CCTA enables direct noninvasive examination of both coronary artery stenoses and atherosclerotic plaque characteristics. Calculation of computational fluid dynamics by cardiac CT allows the noninvasive estimation of fractional flow reserve, which increases the diagnostic accuracy for detection of hemodynamically significant coronary artery disease. In addition, a combination of myocardial CT perfusion and CCTA can provide simultaneous anatomical and functional assessment of coronary artery disease. Finally, detailed anatomical evaluation of atrial, ventricular, and valvular anatomy provides diagnostic information and guidance for procedural planning, such as for transcatheter aortic valve replacement. The clinical applications of cardiac CT will be extended with the development of these novel modalities.

  11. Catheter Angiography

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    Full Text Available ... spaghetti. top of page How does the procedure work? Catheter angiography works much the same as a ... and x-rays. Manufacturers of intravenous contrast indicate mothers should not breastfeed their babies for 24-48 ...

  12. Catheter Angiography

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

  13. Catheter Angiography

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    Full Text Available ... examine blood vessels in key areas of the body for abnormalities such as aneurysms and disease such ... to produce pictures of blood vessels in the body. Angiography is performed using: x-rays with catheters ...

  14. Catheter Angiography

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    Full Text Available ... medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ... identify a small aneurysm or arteriovenous malformation (abnormal communications between blood vessels) inside the brain or other ...

  15. Catheter Angiography

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    Full Text Available ... physicians diagnose and treat medical conditions. Angiography uses one of three imaging technologies and, in most cases, ... evaluating a stent after implantation. detect injury to one or more arteries in the neck, chest, abdomen, ...

  16. Catheter Angiography

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    Full Text Available ... the body for abnormalities such as aneurysms and disease such as atherosclerosis (plaque). The use of a catheter makes it possible to combine diagnosis and treatment in a single procedure. Catheter angiography ...

  17. Catheter Angiography

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    Full Text Available ... Survey Do you have a personal story about radiology? Share your patient story here Images × Image Gallery ... Contrast Materials CT Angiography (CTA) X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to ...

  18. Catheter Angiography

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    Full Text Available ... medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ... that might interfere with the x-ray images. Women should always inform their physician and x-ray ...

  19. Catheter Angiography

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    Full Text Available ... the body absorb the x-rays in varying degrees. Dense bone absorbs much of the radiation while ... by angioplasty and placement of a stent . The degree of detail displayed by catheter angiography may not ...

  20. Catheter Angiography

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    Full Text Available ... medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ... are a form of radiation like light or radio waves. X-rays pass through most objects, including ...

  1. Catheter Angiography

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    Full Text Available ... rays ). top of page What are some common uses of the procedure? Catheter angiography is used to ... Society of Urogenital Radiology note that the available data suggest that it is safe to continue breastfeeding ...

  2. Catheter Angiography

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    Full Text Available ... View full size with caption Related Articles and Media Angioplasty and Vascular Stenting MR Angiography (MRA) Contrast ... or your insurance provider to get a better understanding of the possible charges you will incur. Web ...

  3. Catheter Angiography

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    Full Text Available ... spaghetti. top of page How does the procedure work? Catheter angiography works much the same as a ... material injection, you should immediately inform the technologist. Women should always inform their physician or x-ray ...

  4. Catheter Angiography

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    Full Text Available ... blood flow to the brain and cause a stroke. identify a small aneurysm or arteriovenous malformation (abnormal ... you. top of page What are the benefits vs. risks? Benefits Angiography may eliminate the need for ...

  5. Catheter Angiography

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    Full Text Available ... of a catheter makes it possible to combine diagnosis and treatment in a single procedure. Catheter angiography ... of a catheter makes it possible to combine diagnosis and treatment in a single procedure. An example ...

  6. Catheter Angiography

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    Full Text Available ... diagnosis and treatment in a single procedure. An example is finding an area of severe arterial narrowing, ... contrast material, your radiologist may advise that you take special medication for 24 hours before catheter angiography ...

  7. Catheter Angiography

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    Full Text Available ... identify a small aneurysm or arteriovenous malformation (abnormal communications between blood vessels) inside the brain or other ... iodine. If angiography is essential, a variety of methods is used to decrease risk of allergy: You ...

  8. Catheter Angiography

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    Full Text Available ... in patients after trauma. evaluate arteries feeding a tumor prior to surgery or other procedures such as ... supplying a small area of tissue or a tumor; this is called superselective angiography. Unlike computed tomography ( ...

  9. Catheter Angiography

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

  10. Catheter Angiography

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    Full Text Available ... medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ... branches. show the extent and severity of the effects of coronary artery disease and plan for a ...

  11. Catheter Angiography

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    Full Text Available ... of contrast material to examine blood vessels in key areas of the body for abnormalities such as ... angiography is used to examine blood vessels in key areas of the body, including the: brain neck ...

  12. Catheter Angiography

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    Full Text Available ... disease). evaluate obstructions of vessels. top of page How should I prepare? You should inform your physician ... as a strand of spaghetti. top of page How does the procedure work? Catheter angiography works much ...

  13. Catheter Angiography

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    Full Text Available ... pictures of the blood vessels and may eliminate the need for surgery. Tell your doctor if there's a ... the benefits vs. risks? Benefits Angiography may eliminate the need for surgery. If surgery remains necessary, it can ...

  14. Catheter Angiography

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

  15. Catheter Angiography

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    Full Text Available ... medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ... in key areas of the body, including the: brain neck heart chest abdomen (such as the kidneys ...

  16. Catheter Angiography

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    Full Text Available ... medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ... the exam, you may be admitted to the hospital for an overnight stay if you live more ...

  17. Catheter Angiography

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    Full Text Available ... serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well- ... having a reaction to contrast materials that contain iodine. If angiography is essential, a variety of methods ...

  18. Submillisievert Radiation Dose Coronary CT Angiography: Clinical Impact of the Knowledge-Based Iterative Model Reconstruction.

    Science.gov (United States)

    Iyama, Yuji; Nakaura, Takeshi; Kidoh, Masafumi; Oda, Seitaro; Utsunomiya, Daisuke; Sakaino, Naritsugu; Tokuyasu, Shinichi; Osakabe, Hirokazu; Harada, Kazunori; Yamashita, Yasuyuki

    2016-11-01

    The purpose of this study was to evaluate the noise and image quality of images reconstructed with a knowledge-based iterative model reconstruction (knowledge-based IMR) in ultra-low dose cardiac computed tomography (CT). We performed submillisievert radiation dose coronary CT angiography on 43 patients. We also performed a phantom study to evaluate the influence of object size with the automatic exposure control phantom. We reconstructed clinical and phantom studies with filtered back projection (FBP), hybrid iterative reconstruction (hybrid IR), and knowledge-based IMR. We measured effective dose of patients and compared CT number, image noise, and contrast noise ratio in ascending aorta of each reconstruction technique. We compared the relationship between image noise and body mass index for the clinical study, and object size for phantom study. The mean effective dose was 0.98 ± 0.25 mSv. The image noise of knowledge-based IMR images was significantly lower than those of FBP and hybrid IR images (knowledge-based IMR: 19.4 ± 2.8; FBP: 126.7 ± 35.0; hybrid IR: 48.8 ± 12.8, respectively) (P knowledge-based IMR images was significantly higher than those of FBP and hybrid IR images (knowledge-based IMR: 29.1 ± 5.4; FBP: 4.6 ± 1.3; hybrid IR: 13.1 ± 3.5, respectively) (P knowledge-based IMR (r = 0.27, P knowledge-based IMR offers significant noise reduction and improvement in image quality in submillisievert radiation dose cardiac CT. Copyright © 2016 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

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

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    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.

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

    Science.gov (United States)

    Momeni, Saba; Pourghassem, Hossein

    2014-08-01

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

  1. Prospective series of two hours supine rest after 4fr sheath-based diagnostic cerebral angiography: Outcomes, productivity and cost.

    Science.gov (United States)

    Zuckerman, Scott L; Bhatia, Ritwik; Tsujiara, Crystiana; Baker, Christopher B; Szafran, Alex; Cushing, Deborah; Aiken, Judy; Tracy, Marilyn; Mocco, J; Ecker, Robert D

    2015-02-01

    There is no standard of care for catheter size or post-procedure supine time in cerebral angiography. Catheter sizes range from 4-Fr to 6-Fr with supine times ranging from two to over six hours. The objective of our study was to establish the efficacy, safety, and cost savings of two-hour supine time after 4-Fr elective cerebral angiography. A prospective, single arm study was performed on 107 patients undergoing elective cerebral angiography. All cerebral angiograms were performed with a 4-Fr sheath-based system without closure devices. Ten minutes of manual compression was applied to the femoral access site, with further compression held as clinically indicated. Patients were then monitored in a nursing unit for two hours supine and subsequently mobilized. Nursing discretion was allowed for earlier mobilization. Patients were called the next day to assess delayed hematoma and bleeding. Estimates of cost savings and productivity increases are provided. All patients ambulated in two hours or less. There were no strokes or vessel dissections. Five patients (4.7%) experienced a palpable hematoma, three patients (2.8%) experienced bleeding immediately following the procedure requiring further compression, and one patient (0.9%) experienced minor groin oozing at home. No patient required transfusion, thrombin injection, or endovascular/surgical management of a groin complication. A two-hour post-procedure supine time resulted in cost savings of $952 per angiogram and a total of $101,864. 4-Fr sheath based cerebral angiography with two-hour post-procedure supine time is safe and effective, and allows for a considerable increase in patient satisfaction, cost savings and productivity. © The Author(s) 2015 Reprints and permissions:]br]sagepub.co.uk/journalsPermissions.nav.

  2. Diagnostic Accuracy of Angiography-Based Quantitative Flow Ratio Measurements for Online Assessment of Coronary Stenosis.

    Science.gov (United States)

    Xu, Bo; Tu, Shengxian; Qiao, Shubin; Qu, Xinkai; Chen, Yundai; Yang, Junqing; Guo, Lijun; Sun, Zhongwei; Li, Zehang; Tian, Feng; Fang, Weiyi; Chen, Jiyan; Li, Wei; Guan, Changdong; Holm, Niels R; Wijns, William; Hu, Shengshou

    2017-12-26

    Quantitative flow ratio (QFR) is a novel angiography-based method for deriving fractional flow reserve (FFR) without pressure wire or induction of hyperemia. The accuracy of QFR when assessed online in the catheterization laboratory has not been adequately examined to date. The goal of this study was to assess the diagnostic performance of QFR for the diagnosis of hemodynamically significant coronary stenosis defined by FFR ≤0.80. This prospective, multicenter trial enrolled patients who had at least 1 lesion with a diameter stenosis of 30% to 90% and a reference diameter ≥2 mm according to visual estimation. QFR, quantitative coronary angiography (QCA), and wire-based FFR were assessed online in blinded fashion during coronary angiography and re-analyzed offline at an independent core laboratory. The primary endpoint was that QFR would improve the diagnostic accuracy of coronary angiography such that the lower boundary of the 2-sided 95% confidence interval (CI) of this estimate exceeded 75%. Between June and July 2017, a total of 308 patients were consecutively enrolled at 5 centers. Online QFR and FFR results were both obtained in 328 of 332 interrogated vessels. Patient- and vessel-level diagnostic accuracy of QFR was 92.4% (95% CI: 88.9% to 95.1%) and 92.7% (95% CI: 89.3% to 95.3%), respectively, both of which were significantly higher than the pre-specified target value (p difference: 32.0% [p difference: 36.1% [p Quantitative Flow Ratio in Online Assessment of Coronary Stenosis] II China study]; NCT03191708). Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  3. Catheter Angiography

    Medline Plus

    Full Text Available ... of a catheter makes it possible to combine diagnosis and treatment in a single procedure. Catheter angiography produces very ... of a catheter makes it possible to combine diagnosis and treatment in a single procedure. An example is finding ...

  4. Catheter Angiography

    Medline Plus

    Full Text Available ... the equipment look like? How does the procedure work? How is the procedure performed? What will I experience during and after the procedure? Who interprets the results and how do I get them? What are the benefits vs. risks? What are the limitations of Catheter Angiography? What ...

  5. Catheter Angiography

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    Full Text Available ... small burst of radiation that passes through the body, recording an image on photographic film or a special detector. Different ... about radiology? Share your patient story here Images × ... Related Articles and Media Angioplasty and Vascular Stenting MR Angiography (MRA) Contrast ...

  6. Catheter Angiography

    Medline Plus

    Full Text Available ... spaghetti. top of page How does the procedure work? Catheter angiography works much the same as a regular x-ray ... any possibility that they are pregnant. See the Safety page for more information about pregnancy and x- ...

  7. Catheter Angiography

    Medline Plus

    Full Text Available ... stents or evaluating a stent after implantation. detect injury to one or more arteries in the neck, ... of the radiation while soft tissue, such as muscle, fat and organs, allow more of the ... is called superselective angiography. Unlike computed tomography ( ...

  8. Prevalence and characteristics of coronary artery disease in heart failure with preserved and mid-range ejection fractions: A systematic angiography approach.

    Science.gov (United States)

    Trevisan, Lory; Cautela, Jennifer; Resseguier, Noemie; Laine, Marc; Arques, Stephane; Pinto, Johan; Orabona, Morgane; Barraud, Jeremie; Peyrol, Michael; Paganelli, Franck; Bonello, Laurent; Thuny, Franck

    2018-02-01

    Guidelines recommend careful screening and treatment of coronary artery disease (CAD) in heart failure with preserved or mid-range ejection fraction (HFpEF/HFmEF). We aimed to determine the prevalence and characteristics of CAD using a prospective systematic coronary angiography approach. A systematic coronary angiography protocol was applied in consecutive patients admitted for HFpEF/HFmEF during a 6-month period in a single centre. History of CAD and results of angiography, including revascularization, were reported. Of the 164 patients with HFpEF/HFmEF who were included, an angiography assessment was applied in 108 (66%) (median age: 79 years [interquartile range: 70-85 years]; 54% were women). In our analysis, 64% (95% confidence interval [CI] 55-73%) of patients had a significant coronary stenosis corresponding to a global CAD prevalence of 80% (95% CI 73-88%). The prevalence of CAD was similar for HFpEF and HFmEF. The left main coronary artery presented a significant stenosis in 6.5% of cases and 39% of patients had a two- or three-vessel disease. The rate of significant coronary stenosis was non-significantly higher in patients with a history of CAD. Patients with HFpEF/HFmEF with and without CAD did not differ in clinically meaningful ways, in terms of symptoms or laboratory and echocardiography results. This strategy led to complete revascularization in 36% of patients with significant stenosis and in 23% of all patients with HFpEF/HFmEF. Our study differs from others in that we used a systematic angiography approach. The results suggest a much higher prevalence of CAD in HFpEF/HFmEF than previously reported and should encourage clinicians to aggressively identify this co-morbidity. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  9. Flow prediction in cerebral aneurysms based on geometry reconstruction from 3D rotational angiography

    NARCIS (Netherlands)

    Mikhal, Julia Olegivna; Kroon, Dirk-Jan; Slump, Cornelis H.; Geurts, Bernardus J.

    We present an immersed boundary (IB) method for the simulation of steady blood flow inside a realistic cerebral aneurysm. We reconstruct a segment of the cerebrovascular system that contains an aneurysm, by using medical images obtained with three dimensional rotational angiography (3DRA). The main

  10. 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)

  11. 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

  12. Online Angiography Image-Based FFR Assessment During Coronary Catheterization: A Single-Center Study.

    Science.gov (United States)

    Kornowski, Ran; Vaknin-Assa, Hana; Assali, Abid; Greenberg, Gabriel; Valtzer, Orna; Lavi, Ifat

    2018-03-15

    To assess the diagnostic performance of angiography-derived fractional flow reserve (FFRangio) measurements in patients with stable coronary artery disease when used online in the catheterization laboratory during routine coronary angiography. FFR, an index of the hemodynamic severity of coronary stenosis, is derived from invasive measurements using a pressure-monitoring guidewire and hyperemic stimulus. While FFR is the gold standard, it remains under-utilized. FFRangio may have several advantages owing to the reduced operator time, no wire-related or procedural complications, and no need for administration of vasodilators. FFRangio is a novel technology that uses a patient's hemodynamic data and routine angiograms to generate FFR values at each point along the coronary tree. We present the online application of the system where FFRangio was successfully used in the catheterization laboratory during routine coronary angiography and compared to invasive FFR. Fifty-three patients (79% men) and 60 coronary lesions were analyzed. Values derived using FFRangio ranged from 0.58-0.96 and correlated closely (Pearson's correlation coefficient, r=0.91; Psystem. In this single-center experience, FFRangio values showed high correlation rates to invasive FFR.

  13. Automated coronary artery tree segmentation in X-ray angiography using improved Hessian based enhancement and statistical region merging.

    Science.gov (United States)

    Wan, Tao; Shang, Xiaoqing; Yang, Weilin; Chen, Jianhui; Li, Deyu; Qin, Zengchang

    2018-04-01

    Coronary artery segmentation is a fundamental step for a computer-aided diagnosis system to be developed to assist cardiothoracic radiologists in detecting coronary artery diseases. Manual delineation of the vasculature becomes tedious or even impossible with a large number of images acquired in the daily life clinic. A new computerized image-based segmentation method is presented for automatically extracting coronary arteries from angiography images. A combination of a multiscale-based adaptive Hessian-based enhancement method and a statistical region merging technique provides a simple and effective way to improve the complex vessel structures as well as thin vessel delineation which often missed by other segmentation methods. The methodology was validated on 100 patients who underwent diagnostic coronary angiography. The segmentation performance was assessed via both qualitative and quantitative evaluations. Quantitative evaluation shows that our method is able to identify coronary artery trees with an accuracy of 93% and outperforms other segmentation methods in terms of two widely used segmentation metrics of mean absolute difference and dice similarity coefficient. The comparison to the manual segmentations from three human observers suggests that the presented automated segmentation method is potential to be used in an image-based computerized analysis system for early detection of coronary artery disease. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. 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

  15. Superselective pseudo-continuous arterial spin labeling angiography

    International Nuclear Information System (INIS)

    Jensen-Kondering, Ulf; Lindner, Thomas; Osch, Matthias J.P. van; Rohr, Axel; Jansen, Olav; Helle, Michael

    2015-01-01

    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

  16. 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.)

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

    International Nuclear Information System (INIS)

    Straten, Marcel van; Schaap, Michiel; Dijkshoorn, Marcel L.; Greuter, Marcel J.; Lugt, Aad van der; 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 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

  18. 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

  19. 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.)

  20. Graphics processing unit accelerated intensity-based optical coherence tomography angiography using differential frames with real-time motion correction.

    Science.gov (United States)

    Watanabe, Yuuki; Takahashi, Yuhei; Numazawa, Hiroshi

    2014-02-01

    We demonstrate intensity-based optical coherence tomography (OCT) angiography using the squared difference of two sequential frames with bulk-tissue-motion (BTM) correction. This motion correction was performed by minimization of the sum of the pixel values using axial- and lateral-pixel-shifted structural OCT images. We extract the BTM-corrected image from a total of 25 calculated OCT angiographic images. Image processing was accelerated by a graphics processing unit (GPU) with many stream processors to optimize the parallel processing procedure. The GPU processing rate was faster than that of a line scan camera (46.9 kHz). Our OCT system provides the means of displaying structural OCT images and BTM-corrected OCT angiographic images in real time.

  1. 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

    2016-04-01

    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.

  2. MR angiography

    International Nuclear Information System (INIS)

    Masaryk, T.J.; Ross, J.S.

    1991-01-01

    This paper reports on preliminary research and recent clinical experience which indicates that MR angiography can play a role in routine scanning by providing useful information regarding the anatomy of the cerebral circulation. Used in conjunction with conventional spin-echo studies it may improve the overall sensitivity and specificity of MRI in a cost-effective fashion. It does not, however, replace conventional arteriography at this time for either extracranial or intracranial disease. The use of intravascular contrast agents with new fast-scan techniques also provides dynamic information regarding tissue perfusion in a fashion analogous to that of xenon CT. While this work is preliminary, and the exact agents and mathematical models have yet to be defined, the ability to perform parenchymal, angiographic, and physiologic imaging at a single setting is potentially very powerful. Clearly, the role of MR flow techniques deserves further investigation into possible technical refinements, so that accuracy relative to other diagnostic studies and impact upon patient management can be assessed in a meaningful way

  3. A computer-assisted method for 3D subtraction angiography based on spiral CT

    International Nuclear Information System (INIS)

    Englmeier, K.H.; Fink, U.; Haubner, M.; Becker, C.; Seemann, M.; Capeller, W.; Reiser, M.

    1996-01-01

    The objective of this study was to develop a method for 3D subtraction CT angiography and to optimize the visualization after semiautomatic segmentation. Ten patients with aneurysms of the abdominal aorta were examined using spiral CT. To reconstruct the vessels, as well as adjacent organs such as the liver and kidneys, one image data volume was acquired before and after injection of the contrast agent. The CT scans were obtained with a Siemens Somatom Plus 4. To improve the results of automatic segmentation, as well as visualization by maximum intensity projection (i.e. removal of bony structures), subtraction of both image volumes is necessary. However, small translation shifts disturb the subtraction process and produce artificial contours. To calculate the disparities along the three coordinate axes of two corresponding image volumes, a cepstrum filter is applied to a pair of image volumes. After detection of the disparities, which manifest as bright spots, the real shift of the two subsignals can be calculated. Translation of the corresponding image volume pairs to their correct positions improves the subtraction process. In all cases the size of the aneurysm and the abdominal organs could be better segmented and visualized. Application of the cepstrum filter and subtraction of the image volumes before, and after contrast medium injection completely removes the bony structures in the image data and results in superior visualization results. (orig./MG) [de

  4. Image Intensifier-Based CT Volume Imager For Angiography: System Evaluation

    Science.gov (United States)

    Ning, Ruola; Kruger, Robert A.; Hu, Hui

    1989-05-01

    A prototype volume CT system for use in angiography has been modified and tested using three different phantoms. This system consists of a fixed x-ray tube, a conventional image intensifier coupled to a charge-coupled device (CCD) camera, a computer-controlled turntable on which phantoms were placed. In order to explore the imaging performance of the system for reconstructing a three dimension (3D) vascular structure, two sets of projection images of a vascular phantom, acquired over 250 projection angles with two different sizes of image intensifier were digitized and used for a direct 3D cone beam reconstruction. The spatial resolution limits of the system were measured from the 3D reconstructed images of a specially-designed resolution phantom. The direct 3D reconstructions of a Humanoid chest phantom were obtained using this system to show the perspective of the system for a general medical application with 3D imaging. The quality of the reconstructed images indicates that the system can be used for achieving a direct 3D reconstruction of a vascular structure as well as a general 3D object. The measured spatial resolution of the system is nearly half of the nominal resolution of the image intensifier and is reduced around the edge of the image intensifier, primarily because of the pincushion distortion.

  5. Prospective series of two hours supine rest after 4fr sheath-based diagnostic cerebral angiography: Outcomes, productivity and cost

    OpenAIRE

    Zuckerman, Scott L; Bhatia, Ritwik; Tsujiara, Crystiana; Baker, Christopher B; Szafran, Alex; Cushing, Deborah; Aiken, Judy; Tracy, Marilyn; Mocco, J; Ecker, Robert D

    2015-01-01

    There is no standard of care for catheter size or post-procedure supine time in cerebral angiography. Catheter sizes range from 4-Fr to 6-Fr with supine times ranging from two to over six hours. The objective of our study was to establish the efficacy, safety, and cost savings of two-hour supine time after 4-Fr elective cerebral angiography. A prospective, single arm study was performed on 107 patients undergoing elective cerebral angiography. All cerebral angiograms were performed with a 4-F...

  6. Transaction based approach

    Science.gov (United States)

    Hunka, Frantisek; Matula, Jiri

    2017-07-01

    Transaction based approach is utilized in some methodologies in business process modeling. Essential parts of these transactions are human beings. The notion of agent or actor role is usually used for them. The paper on a particular example describes possibilities of Design Engineering Methodology for Organizations (DEMO) and Resource-Event-Agent (REA) methodology. Whereas the DEMO methodology can be regarded as a generic methodology having its foundation in the theory of Enterprise Ontology the REA methodology is regarded as the domain specific methodology and has its origin in accountancy systems. The results of these approaches is that the DEMO methodology captures everything that happens in the reality with a good empirical evidence whereas the REA methodology captures only changes connected with economic events. Economic events represent either change of the property rights to economic resource or consumption or production of economic resources. This results from the essence of economic events and their connection to economic resources.

  7. Phantom-based standardization of CT angiography images for spot sign detection

    Energy Technology Data Exchange (ETDEWEB)

    Morotti, Andrea; Rosand, Jonathan [Harvard Medical School, Division of Neurocritical Care and Emergency Neurology, Department of Neurology, Massachusetts General Hospital, Boston, MA (United States); Harvard Medical School, J. P. Kistler Stroke Research Center, Massachusetts General Hospital, Boston, MA (United States); Romero, Javier M. [Harvard Medical School, Division of Neurocritical Care and Emergency Neurology, Department of Neurology, Massachusetts General Hospital, Boston, MA (United States); Harvard Medical School, J. P. Kistler Stroke Research Center, Massachusetts General Hospital, Boston, MA (United States); Harvard Medical School, Neuroradiology Service, Department of Radiology, Massachusetts General Hospital, Boston, MA (United States); Jessel, Michael J.; Vashkevich, Anastasia; Schwab, Kristin; Greenberg, Steven M. [Harvard Medical School, J. P. Kistler Stroke Research Center, Massachusetts General Hospital, Boston, MA (United States); Hernandez, Andrew M.; Boone, John M. [University of California Davis, Department of Radiology, Sacramento, CA (United States); Burns, Joseph D. [Lahey Hospital and Medical Center, Department of Neurology, Burlington, MA (United States); Shah, Qaisar A. [Abington Memorial Hospital, Abington, PA (United States); Bergman, Thomas A. [Hennepin County Medical Center, Minneapolis, MN (United States); Suri, M.F.K. [St. Cloud Hospital, St. Cloud, MN (United States); Ezzeddine, Mustapha [University of Minnesota, Minneapolis, MN (United States); Kirmani, Jawad F. [JFK Medical Center, Stroke and Neurovascular Center, Edison, NJ (United States); Agarwal, Sachin [Columbia University Medical Center, New York, NY (United States); Hays Shapshak, Angela [University of Alabama at Birmingham, Birmingham, AL (United States); Messe, Steven R. [University of Pennsylvania, Philadelphia, PA (United States); Venkatasubramanian, Chitra [Stanford University, Stanford, CA (United States); Palmieri, Katherine [The University of Kansas Health System, Kansas City, KS (United States); Lewandowski, Christopher [Henry Ford Hospital, Detroit, MI (United States); Chang, Tiffany R. [University of Texas Medical School, Houston, TX (United States); Chang, Ira [Colorado Neurological Institute, Swedish Medical Center, Englewood, CO (United States); Rose, David Z. [Tampa General Hospital, University of South Florida College of Medicine, Tampa, FL (United States); Smith, Wade [UCSF Medical Center, San Francisco, CA (United States); Hsu, Chung Y.; Liu, Chun-Lin [China Medical University Hospital, Taichung (China); Lien, Li-Ming; Hsiao, Chen-Yu [Shin Kong Wu Ho-Su Memorial Hospital, Taipei (China); Iwama, Toru [Gifu University Hospital, Gifu (Japan); Afzal, Mohammad Rauf; Qureshi, Adnan I. [University of Minnesota, Zeenat Qureshi Stroke Research Center, Minneapolis, MN (United States); Cassarly, Christy; Hebert Martin, Renee [Medical University of South Carolina, Department of Public Health Sciences, Charleston, SC (United States); Goldstein, Joshua N. [Harvard Medical School, Division of Neurocritical Care and Emergency Neurology, Department of Neurology, Massachusetts General Hospital, Boston, MA (United States); Harvard Medical School, J. P. Kistler Stroke Research Center, Massachusetts General Hospital, Boston, MA (United States); Harvard Medical School, Department of Emergency Medicine, Massachusetts General Hospital, Boston, MA (United States); Collaboration: ATACH-II and NETT Investigators

    2017-09-15

    The CT angiography (CTA) spot sign is a strong predictor of hematoma expansion in intracerebral hemorrhage (ICH). However, CTA parameters vary widely across centers and may negatively impact spot sign accuracy in predicting ICH expansion. We developed a CT iodine calibration phantom that was scanned at different institutions in a large multicenter ICH clinical trial to determine the effect of image standardization on spot sign detection and performance. A custom phantom containing known concentrations of iodine was designed and scanned using the stroke CT protocol at each institution. Custom software was developed to read the CT volume datasets and calculate the Hounsfield unit as a function of iodine concentration for each phantom scan. CTA images obtained within 8 h from symptom onset were analyzed by two trained readers comparing the calibrated vs. uncalibrated density cutoffs for spot sign identification. ICH expansion was defined as hematoma volume growth >33%. A total of 90 subjects qualified for the study, of whom 17/83 (20.5%) experienced ICH expansion. The number of spot sign positive scans was higher in the calibrated analysis (67.8 vs 38.9% p < 0.001). All spot signs identified in the non-calibrated analysis remained positive after calibration. Calibrated CTA images had higher sensitivity for ICH expansion (76 vs 52%) but inferior specificity (35 vs 63%) compared with uncalibrated images. Normalization of CTA images using phantom data is a feasible strategy to obtain consistent image quantification for spot sign analysis across different sites and may improve sensitivity for identification of ICH expansion. (orig.)

  8. Phantom-based standardization of CT angiography images for spot sign detection.

    Science.gov (United States)

    Morotti, Andrea; Romero, Javier M; Jessel, Michael J; Hernandez, Andrew M; Vashkevich, Anastasia; Schwab, Kristin; Burns, Joseph D; Shah, Qaisar A; Bergman, Thomas A; Suri, M Fareed K; Ezzeddine, Mustapha; Kirmani, Jawad F; Agarwal, Sachin; Shapshak, Angela Hays; Messe, Steven R; Venkatasubramanian, Chitra; Palmieri, Katherine; Lewandowski, Christopher; Chang, Tiffany R; Chang, Ira; Rose, David Z; Smith, Wade; Hsu, Chung Y; Liu, Chun-Lin; Lien, Li-Ming; Hsiao, Chen-Yu; Iwama, Toru; Afzal, Mohammad Rauf; Cassarly, Christy; Greenberg, Steven M; Martin, Renee' Hebert; Qureshi, Adnan I; Rosand, Jonathan; Boone, John M; Goldstein, Joshua N

    2017-09-01

    The CT angiography (CTA) spot sign is a strong predictor of hematoma expansion in intracerebral hemorrhage (ICH). However, CTA parameters vary widely across centers and may negatively impact spot sign accuracy in predicting ICH expansion. We developed a CT iodine calibration phantom that was scanned at different institutions in a large multicenter ICH clinical trial to determine the effect of image standardization on spot sign detection and performance. A custom phantom containing known concentrations of iodine was designed and scanned using the stroke CT protocol at each institution. Custom software was developed to read the CT volume datasets and calculate the Hounsfield unit as a function of iodine concentration for each phantom scan. CTA images obtained within 8 h from symptom onset were analyzed by two trained readers comparing the calibrated vs. uncalibrated density cutoffs for spot sign identification. ICH expansion was defined as hematoma volume growth >33%. A total of 90 subjects qualified for the study, of whom 17/83 (20.5%) experienced ICH expansion. The number of spot sign positive scans was higher in the calibrated analysis (67.8 vs 38.9% p signs identified in the non-calibrated analysis remained positive after calibration. Calibrated CTA images had higher sensitivity for ICH expansion (76 vs 52%) but inferior specificity (35 vs 63%) compared with uncalibrated images. Normalization of CTA images using phantom data is a feasible strategy to obtain consistent image quantification for spot sign analysis across different sites and may improve sensitivity for identification of ICH expansion.

  9. Nonenhanced MR angiography techniques

    International Nuclear Information System (INIS)

    Lanzman, R.S.; Kroepil, P.; Blondin, D.; Schmitt, P.

    2011-01-01

    Especially in regard to the potential risks for the development of nephrogenic systemic fibrosis (NSF) following the administration of Gadolinium-based contrast material, nonenhanced MR angiography (MRA) methods are becoming ever more important. Besides well-established time-of-flight (TOF) and phase-contrast (PC) MRA, alternative imaging techniques based on balanced steady-state free precession (bSSFP) and turbo-spin-echo (TSE) sequences are increasingly used in combination with or without arterial spin labeling (ASL) strategies. This article provides an overview of the principles and clinical values of different nonenhanced MRA techniques. In addition, recent nonenhanced MRA developments are presented. (orig.)

  10. Angiography in angiology

    International Nuclear Information System (INIS)

    Zeitler, E.; Grosse-Vorholt, R.

    1980-01-01

    A review is given of recent developments in angiography including advances in the equipment, in the technique and in image processing. Indications for and interpretation of angiography are discussed and angiographic-therapeutic procedures are considered. (C.F.)

  11. Comparative study of the use of diltiazem as an antispasmodic drug in coronary angiography via the transradial approach

    Directory of Open Access Journals (Sweden)

    José Ronaldo Mont'Alverne Filho

    2003-07-01

    Full Text Available OBJECTIVE: To evaluate the impact of the use, prior to the procedure, of injectable diltiazem to prevent complications. METHODS: Between September 2000 and July 2001, 50 patients underwent transradial coronary angiography and were randomized to receive placebo (GI or diltiazem (GII through a catheter inserted into the radial artery. All patients received isosorbide mononitrate. Ultrasound analyses of the radial artery were performed before examination, 30 minutes afterwards, and 7 days afterwards to evaluate the flow, the diameter, and the artery output. RESULTS: The radial artery diameter of GI was 2.4± 0.5 mm before the procedure and 2.3±0.5 mm after 30 minutes (NS, whereas in GII the diameter was 2.2±0.3 mm before the examination and 2.5±0.4 mm 30 minutes after it (P<0.001. Radial artery output in group 1 was 7.3±5.l2 mL/min before the examination and 6.1±3.5 mL/min 30 minutes after the examination (NS, and GII had an increase of 5.9±2.5 mL/min before examination to 9.05± 7.78 mL/min after the examination (P=0.04. Complications (spasm, occlusion, and partial obstruction occurred in 4 patients (17.4% in GI and did not occur in GII (P=0.04. CONCLUSION: The study suggests a decrease in vascular complications through the transradial access for coronary angiography with the use of diltiazem as an antispasmodic drug, resulting in the significant increase in the diameter of the radial artery and radial artery output.

  12. Coronary CT Angiography-derived Fractional Flow Reserve.

    Science.gov (United States)

    Tesche, Christian; De Cecco, Carlo N; Albrecht, Moritz H; Duguay, Taylor M; Bayer, Richard R; Litwin, Sheldon E; Steinberg, Daniel H; Schoepf, U Joseph

    2017-10-01

    Invasive coronary angiography (ICA) with measurement of fractional flow reserve (FFR) by means of a pressure wire technique is the established reference standard for the functional assessment of coronary artery disease (CAD) ( 1 , 2 ). Coronary computed tomographic (CT) angiography has emerged as a noninvasive method for direct assessment of CAD and plaque characterization with high diagnostic accuracy compared with ICA ( 3 , 4 ). However, the solely anatomic assessment provided with both coronary CT angiography and ICA has poor discriminatory power for ischemia-inducing lesions. FFR derived from standard coronary CT angiography (FFR CT ) data sets by using any of several advanced computational analytic approaches enables combined anatomic and hemodynamic assessment of a coronary lesion by a single noninvasive test. Current technical approaches to the calculation of FFR CT include algorithms based on full- and reduced-order computational fluid dynamic modeling, as well as artificial intelligence deep machine learning ( 5 , 6 ). A growing body of evidence has validated the diagnostic accuracy of FFR CT techniques compared with invasive FFR. Improved therapeutic guidance has been demonstrated, showing the potential of FFR CT to streamline and rationalize the care of patients suspected of having CAD and improve outcomes while reducing overall health care costs ( 7 , 8 ). The purpose of this review is to describe the scientific principles, clinical validation, and implementation of various FFR CT approaches, their precursors, and related imaging tests. © RSNA, 2017.

  13. Myocardial segmentation based on coronary anatomy using coronary computed tomography angiography: Development and validation in a pig model

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Mi Sun [Chung-Ang University College of Medicine, Department of Radiology, Chung-Ang University Hospital, Seoul (Korea, Republic of); Yang, Dong Hyun; Seo, Joon Beom; Kang, Joon-Won; Lim, Tae-Hwan [Asan Medical Center, University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of); Kim, Young-Hak; Kang, Soo-Jin; Jung, Joonho [Asan Medical Center, University of Ulsan College of Medicine, Heart Institute, Seoul (Korea, Republic of); Kim, Namkug [Asan Medical Center, University of Ulsan College of Medicine, Department of Convergence Medicine, Seoul (Korea, Republic of); Heo, Seung-Ho [Asan Medical Center, University of Ulsan College of Medicine, Asan institute for Life Science, Seoul (Korea, Republic of); Baek, Seunghee [Asan Medical Center, University of Ulsan College of Medicine, Department of Clinical Epidemiology and Biostatistics, Seoul (Korea, Republic of); Choi, Byoung Wook [Yonsei University, Department of Diagnostic Radiology, College of Medicine, Seoul (Korea, Republic of)

    2017-10-15

    To validate a method for performing myocardial segmentation based on coronary anatomy using coronary CT angiography (CCTA). Coronary artery-based myocardial segmentation (CAMS) was developed for use with CCTA. To validate and compare this method with the conventional American Heart Association (AHA) classification, a single coronary occlusion model was prepared and validated using six pigs. The unstained occluded coronary territories of the specimens and corresponding arterial territories from CAMS and AHA segmentations were compared using slice-by-slice matching and 100 virtual myocardial columns. CAMS more precisely predicted ischaemic area than the AHA method, as indicated by 95% versus 76% (p < 0.001) of the percentage of matched columns (defined as percentage of matched columns of segmentation method divided by number of unstained columns in the specimen). According to the subgroup analyses, CAMS demonstrated a higher percentage of matched columns than the AHA method in the left anterior descending artery (100% vs. 77%; p < 0.001) and mid- (99% vs. 83%; p = 0.046) and apical-level territories of the left ventricle (90% vs. 52%; p = 0.011). CAMS is a feasible method for identifying the corresponding myocardial territories of the coronary arteries using CCTA. (orig.)

  14. The branching pattern of the deep inferior epigastric artery revisited in-vivo: a new classification based on CT angiography.

    Science.gov (United States)

    Rozen, Warren M; Ashton, Mark W; Grinsell, Damien

    2010-01-01

    The deep inferior epigastric artery (DIEA) is a reliable pedicle in the design of DIEA perforator flaps, with variations in its anatomy infrequent. Previous studies describing its branching pattern have all been based on cadaveric anatomy and described the following three branching patterns: Type 1 (single trunk), Type 2 (bifurcating trunk), and Type 3 (trifurcating trunk). The increased use of preoperative imaging, particularly with computed tomographic angiography (CTA), has enabled visualization of the DIEA and its branches in vivo, providing a functional view of this anatomy. We undertook a study of 250 patients (500 hemiabdominal walls) undergoing preoperative CTA before DIEA perforator flaps for breast reconstruction. The branching pattern of the DIEA and correlation to the contralateral hemiabdominal wall were assessed. The branching patterns of the DIEA were found to be different in vivo compared with cadaveric studies, with a higher than previously reported incidence of Type 1 patterns and lower than reported incidence of Type 3 patterns, and that some patterns exist which were not included within the previous nomenclature (namely, Type 0 or absent DIEA and Type 4 or four-trunk DIEA). There was also shown to be no overall concordance in the branching patterns of the DIEA between contralateral sides of the same abdominal wall; however, there was shown to be a statistically significant concordance in cases of a Type 1 DIEA (51% concordance, P = 0.04). As such, a new modification to the classification system for the branching pattern of the DIEA is presented based on imaging findings.

  15. 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.

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

    Science.gov (United States)

    Schrauwen, Jelle T. C.; Karanasos, Antonios; van Ditzhuijzen, Nienke S.; Aben, Jean-Paul; van der Steen, Antonius F. W.

    2015-01-01

    Introduction 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. Materials Methods 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. Results 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. Discussion 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

  17. Imaging of the digital arteries: Digital subtraction angiography versus conventional angiography

    International Nuclear Information System (INIS)

    Menanteau, B.P.; Treutenaere, J.M.; Marcus, C.; Ladam, V.; Gausserand, F.

    1986-01-01

    The authors report their experience with the use of digital subtraction angiography (DSA) and conventional angiography of the hand. Of the 95 patients in the study group, 80 underwent conventional angiography and 15 underwent DSA. They analyzed the studies with regard to the type and amount of contrast agent used, the number of radiographs needed, and the diagnostic quality of the images. Conventional angiography often requires general anesthesia, magnification, and pharmaco-angiographic techniques to improve the image-based diagnosis. In comparison with conventional angiography, intraarterial DSA is characterized by improved contrast sensitivity and inferior spatial resolution. However, DSA provides images as acceptable as those of conventional angiography. Smaller catheters can be used, and the examination is performed under local anesthesia. The authors conclude that intraarterial DSA is now the technique of choice for examining patients with chronic ischemia of the hand

  18. Technical note: A preliminary comparative study between classical and interventional radiological approaches for multi-phase post-mortem CT angiography.

    Science.gov (United States)

    Mokrane, Fatima-Zohra; Savall, Frederic; Dercle, Laurent; Crubezy, Eric; Telmon, Norbert; Rousseau, Hervé; Dedouit, Fabrice

    2017-02-01

    Multi-phase post-mortem computed tomography angiography (MPMCTA) is a new diagnostic tool, used in forensic pathology. On the one hand, this technique allows a better and direct visualization of vascular and solid organ lesions. On the other hand, the invasiveness of the procedure-which requires surgical denudation (inguinal and/or cervical) and the insertion of surgical cannulas-leads to many relatives refusing scientific autopsies. Our hypothesis states that a minimally-invasive procedure combining interventional radiological techniques with MPMCTA (replacement of surgical cannulas by radiological catheters) will improve the approval rate of scientific autopsies by families. The aim of this study was to evaluate the feasibility of the minimally-invasive MPMCTA approach and to compare its performance to the current reference-standard (the conventional approach). We included consecutively 16 corpses divided in two groups according to the contrast enhancement approach: radiological catheters (n=8), and surgical cannulas (n=8). Corpses were chosen and assigned randomly from our local data. The quality of the imaging procedure was compared according to four items: global vascular opacification, cerebral venous opacification, and lower limbs opacification (arterial and venous). A minimally-invasive approach for scientific autopsies is feasible through a radiological catheter. Vascular opacification was optimal in 8 out of 8 cases and was no less effective than the control reference group using surgical cannula incision associated with their non-occlusive aspects. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. 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%.

  20. True four-dimensional analysis of thoracic aortic displacement and distension using model-based segmentation of computed tomography angiography.

    Science.gov (United States)

    Weber, Tim F; Müller, Tobias; Biesdorf, Andreas; Wörz, Stefan; Rengier, Fabian; Heye, Tobias; Holland-Letz, Tim; Rohr, Karl; Kauczor, Hans-Ulrich; von Tengg-Kobligk, Hendrik

    2014-01-01

    Previous analyses of aortic displacement and distension using computed tomography angiography (CTA) were performed on double-oblique multi-planar reformations and did not consider through-plane motion. The aim of this study was to overcome this limitation by using a novel computational approach for the assessment of thoracic aortic displacement and distension in their true four-dimensional extent. Vessel segmentation with landmark tracking was executed on CTA of 24 patients without evidence of aortic disease. Distension magnitudes and maximum displacement vectors (MDV) including their direction were analyzed at 5 aortic locations: left coronary artery (COR), mid-ascending aorta (ASC), brachiocephalic trunk (BCT), left subclavian artery (LSA), descending aorta (DES). Distension was highest for COR (2.3 ± 1.2 mm) and BCT (1.7 ± 1.1 mm) compared with ASC, LSA, and DES (p < 0.005). MDV decreased from COR to LSA (p < 0.005) and was highest for COR (6.2 ± 2.0 mm) and ASC (3.8 ± 1.9 mm). Displacement was directed towards left and anterior at COR and ASC. Craniocaudal displacement at COR and ASC was 1.3 ± 0.8 and 0.3 ± 0.3 mm. At BCT, LSA, and DES no predominant displacement direction was observable. Vessel displacement and wall distension are highest in the ascending aorta, and ascending aortic displacement is primarily directed towards left and anterior. Craniocaudal displacement remains low even close to the left cardiac ventricle.

  1. Coronary CT Angiography-derived Fractional Flow Reserve: Machine Learning Algorithm versus Computational Fluid Dynamics Modeling.

    Science.gov (United States)

    Tesche, Christian; De Cecco, Carlo N; Baumann, Stefan; Renker, Matthias; McLaurin, Tindal W; Duguay, Taylor M; Bayer, Richard R; Steinberg, Daniel H; Grant, Katharine L; Canstein, Christian; Schwemmer, Chris; Schoebinger, Max; Itu, Lucian M; Rapaka, Saikiran; Sharma, Puneet; Schoepf, U Joseph

    2018-04-10

    Purpose To compare two technical approaches for determination of coronary computed tomography (CT) angiography-derived fractional flow reserve (FFR)-FFR derived from coronary CT angiography based on computational fluid dynamics (hereafter, FFR CFD ) and FFR derived from coronary CT angiography based on machine learning algorithm (hereafter, FFR ML )-against coronary CT angiography and quantitative coronary angiography (QCA). Materials and Methods A total of 85 patients (mean age, 62 years ± 11 [standard deviation]; 62% men) who had undergone coronary CT angiography followed by invasive FFR were included in this single-center retrospective study. FFR values were derived on-site from coronary CT angiography data sets by using both FFR CFD and FFR ML . The performance of both techniques for detecting lesion-specific ischemia was compared against visual stenosis grading at coronary CT angiography, QCA, and invasive FFR as the reference standard. Results On a per-lesion and per-patient level, FFR ML showed a sensitivity of 79% and 90% and a specificity of 94% and 95%, respectively, for detecting lesion-specific ischemia. Meanwhile, FFR CFD resulted in a sensitivity of 79% and 89% and a specificity of 93% and 93%, respectively, on a per-lesion and per-patient basis (P = .86 and P = .92). On a per-lesion level, the area under the receiver operating characteristics curve (AUC) of 0.89 for FFR ML and 0.89 for FFR CFD showed significantly higher discriminatory power for detecting lesion-specific ischemia compared with that of coronary CT angiography (AUC, 0.61) and QCA (AUC, 0.69) (all P < .0001). Also, on a per-patient level, FFR ML (AUC, 0.91) and FFR CFD (AUC, 0.91) performed significantly better than did coronary CT angiography (AUC, 0.65) and QCA (AUC, 0.68) (all P < .0001). Processing time for FFR ML was significantly shorter compared with that of FFR CFD (40.5 minutes ± 6.3 vs 43.4 minutes ± 7.1; P = .042). Conclusion The FFR ML algorithm performs equally in

  2. Utility of digital subtraction angiography-based collateral evaluation in medically treated acute symptomatic basilar artery stenosis.

    Science.gov (United States)

    Lee, W-J; Jung, K-H; Ryu, Y J; Kim, J-M; Lee, S-T; Chu, K; Kim, M; Lee, S K; Roh, J-K

    2017-09-01

    Although a stroke from atherosclerosis in the basilar artery (BA) often presents with mild initial stroke severity, it has heterogeneous clinical courses. We investigated the efficacy of digital subtraction angiography (DSA)-based collateral perfusion evaluation in association with long-term outcomes of medically treated symptomatic basilar artery stenosis. From a registry database of all consecutive patients with stroke, we included 98 medically treated patients (due to mild initial stroke severity) [National Institute of Health Stroke Scale (NIHSS) scores ≤ 4; symptomatic basilar artery stenosis, 70-99%] with available initial diagnostic DSA. Basilar collateral scoring was performed via the DSA, using a modified version of the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology grading system in both the superior cerebellar artery and anterior/posterior-inferior cerebellar artery territories (score 0-8). The outcomes were designated as the 90-day modified Rankin Scale (mRS90) score (poor, 3-6). Student's t-test, chi-square test and logistic regression analyses were used to identify factors associated with a poor outcome. The median initial NIHSS score was 2 [interquartile range (IQR), 0-3], median posterior circulation Alberta Stroke Program Early CT Score was 8 (IQR, 7-10), median collateral score was 7 (IQR, 7-8) and 20 (20.4%) had poor mRS90 scores. In multivariate analysis, poorer collateral scores (P = 0.003), higher NIHSS scores (P = 0.005) and lower posterior circulation Alberta Stroke Program Early CT Score (P = 0.017) were independently associated with a poor mRS90 score. The DSA-based collateral scoring of the BA large branches might predict long-term outcome in medically treated symptomatic basilar artery stenosis with mild initial severity. Evaluation of BA collateral perfusion status might be useful to determine appropriate treatment strategies. © 2017 EAN.

  3. Magnetic resonance angiography (MRA)

    International Nuclear Information System (INIS)

    Arlart, I.P.; Guhl, L.

    1992-01-01

    An account is given in this paper of the physical and technical principles underlying the 'time-of-flight' technique for imaging of vessels by magnetic resonance tomography. Major indications for the new procedure of magnetic resonance angiography at present are intracerebral and extracerebral vessels, with digital subtraction angiography quite often being required to cope with minor alterations (small aneurysms, small occlusions). Magnetic resonance angiography and digital subtraction angiography are compared to each other for advantages and disadvantages. Basically, replacement of radiological angiography by magnetic resonance angiography appears to be possible only within limits, since X-ray diagnostics primarily provides morphological information about vessels, whereas flow dynamics is visualized by the 'time-of-flight' technique. (orig.) [de

  4. Behavioral based safety approaches

    International Nuclear Information System (INIS)

    Maria Michael Raj, I.

    2009-01-01

    Approach towards the establishment of positive safety culture at Heavy Water Plant, Tuticorin includes the adoption of several important methodologies focused on human behavior and culminates with achievement of Total Safety Culture where Quality and Productivity are integrated with Safety

  5. Automated 3D Volumetry of the Pulmonary Arteries based on Magnetic Resonance Angiography Has Potential for Predicting Pulmonary Hypertension.

    Directory of Open Access Journals (Sweden)

    Fabian Rengier

    Full Text Available To demonstrate feasibility of automated 3D volumetry of central pulmonary arteries based on magnetic resonance angiography (MRA, to assess pulmonary artery volumes in patients with pulmonary hypertension compared to healthy controls, and to investigate the potential of the technique for predicting pulmonary hypertension.MRA of pulmonary arteries was acquired at 1.5T in 20 patients with pulmonary arterial hypertension and 21 healthy normotensive controls. 3D model-based image analysis software was used for automated segmentation of main, right and left pulmonary arteries (MPA, RPA and LPA. Volumes indexed to vessel length and mean, minimum and maximum diameters along the entire vessel course were assessed and corrected for body surface area (BSA. For comparison, diameters were also manually measured on axial reconstructions and double oblique multiplanar reformations. Analyses were performed by two cardiovascular radiologists, and by one radiologist again after 6 months.Mean volumes of MPA, RPA and LPA for patients/controls were 5508 ± 1236/3438 ± 749, 3522 ± 934/1664 ± 468 and 3093 ± 692/1812 ± 474 μl/(cm length x m2 BSA (all p<0.001. Mean, minimum and maximum diameters along the entire vessel course were also significantly increased in patients compared to controls (all p<0.001. Intra- and interobserver agreement were excellent for both volume and diameter measurements using 3D segmentation (intraclass correlation coefficients 0.971-0.999, p<0.001. Area under the curve for predicting pulmonary hypertension using volume was 0.998 (95% confidence interval 0.990-1.0, p<0.001, compared to 0.967 using manually measured MPA diameter (95% confidence interval 0.910-1.0, p<0.001.Automated MRA-based 3D volumetry of central pulmonary arteries is feasible and demonstrated significantly increased volumes and diameters in patients with pulmonary arterial hypertension compared to healthy controls. Pulmonary artery volume may serve as a superior

  6. Automated 3D Volumetry of the Pulmonary Arteries based on Magnetic Resonance Angiography Has Potential for Predicting Pulmonary Hypertension.

    Science.gov (United States)

    Rengier, Fabian; Wörz, Stefan; Melzig, Claudius; Ley, Sebastian; Fink, Christian; Benjamin, Nicola; Partovi, Sasan; von Tengg-Kobligk, Hendrik; Rohr, Karl; Kauczor, Hans-Ulrich; Grünig, Ekkehard

    2016-01-01

    To demonstrate feasibility of automated 3D volumetry of central pulmonary arteries based on magnetic resonance angiography (MRA), to assess pulmonary artery volumes in patients with pulmonary hypertension compared to healthy controls, and to investigate the potential of the technique for predicting pulmonary hypertension. MRA of pulmonary arteries was acquired at 1.5T in 20 patients with pulmonary arterial hypertension and 21 healthy normotensive controls. 3D model-based image analysis software was used for automated segmentation of main, right and left pulmonary arteries (MPA, RPA and LPA). Volumes indexed to vessel length and mean, minimum and maximum diameters along the entire vessel course were assessed and corrected for body surface area (BSA). For comparison, diameters were also manually measured on axial reconstructions and double oblique multiplanar reformations. Analyses were performed by two cardiovascular radiologists, and by one radiologist again after 6 months. Mean volumes of MPA, RPA and LPA for patients/controls were 5508 ± 1236/3438 ± 749, 3522 ± 934/1664 ± 468 and 3093 ± 692/1812 ± 474 μl/(cm length x m2 BSA) (all p<0.001). Mean, minimum and maximum diameters along the entire vessel course were also significantly increased in patients compared to controls (all p<0.001). Intra- and interobserver agreement were excellent for both volume and diameter measurements using 3D segmentation (intraclass correlation coefficients 0.971-0.999, p<0.001). Area under the curve for predicting pulmonary hypertension using volume was 0.998 (95% confidence interval 0.990-1.0, p<0.001), compared to 0.967 using manually measured MPA diameter (95% confidence interval 0.910-1.0, p<0.001). Automated MRA-based 3D volumetry of central pulmonary arteries is feasible and demonstrated significantly increased volumes and diameters in patients with pulmonary arterial hypertension compared to healthy controls. Pulmonary artery volume may serve as a superior predictor for

  7. Coronary CT angiography: Diagnostic value and clinical challenges.

    Science.gov (United States)

    Sabarudin, Akmal; Sun, Zhonghua

    2013-12-26

    Coronary computed tomography (CT) angiography has been increasingly used in the diagnosis of coronary artery disease due to improved spatial and temporal resolution with high diagnostic value being reported when compared to invasive coronary angiography. Diagnostic performance of coronary CT angiography has been significantly improved with the technological developments in multislice CT scanners from the early generation of 4-slice CT to the latest 320- slice CT scanners. Despite the promising diagnostic value, coronary CT angiography is still limited in some areas, such as inferior temporal resolution, motion-related artifacts and high false positive results due to severe calcification. The aim of this review is to present an overview of the technical developments of multislice CT and diagnostic value of coronary CT angiography in coronary artery disease based on different generations of multislice CT scanners. Prognostic value of coronary CT angiography in coronary artery disease is also discussed, while limitations and challenges of coronary CT angiography are highlighted.

  8. Intravenous volume tomographic pulmonary angiography imaging

    Science.gov (United States)

    Ning, Ruola; Strang, John G.; Chen, Biao; Conover, David L.; Yu, Rongfeng

    1999-05-01

    This study presents a new intravenous (IV) tomographic angiography imaging technique, called intravenous volume tomographic digital angiography (VTDA) for cross sectional pulmonary angiography. While the advantages of IV-VTDA over spiral CT in terms of volume scanning time and resolution have been validated and reported in our previous papers for head and neck vascular imaging, the superiority of IV-VTDA over spiral CT for cross sectional pulmonary angiography has not been explored yet. The purpose of this study is to demonstrate the advantage of isotropic resolution of IV-VTDA in the x, y and z directions through phantom and animal studies, and to explore its clinical application for detecting clots in pulmonary angiography. A prototype image intensifier-based VTDA imaging system has been designed and constructed by modifying a GE 8800 CT scanner. This system was used for a series of phantom and dog studies. A pulmonary vascular phantom was designed and constructed. The phantom was scanned using the prototype VTDA system for direct 3D reconstruction. Then the same phantom was scanned using a GE CT/i spiral CT scanner using the routine pulmonary CT angiography protocols. IV contrast injection and volume scanning protocols were developed during the dog studies. Both VTDA reconstructed images and spiral CT images of the specially designed phantom were analyzed and compared. The detectability of simulated vessels and clots was assessed as the function of iodine concentration levels, oriented angles, and diameters of the vessels and clots. A set of 3D VTDA reconstruction images of dog pulmonary arteries was obtained with different IV injection rates and isotropic resolution in the x, y and z directions. The results of clot detection studies in dog pulmonary arteries have also been shown. This study presents a new tomographic IV angiography imaging technique for cross sectional pulmonary angiography. The results of phantom and animal studies indicate that IV-VTDA is

  9. Renal artery intervention utilizing carbon dioxide angiography.

    Science.gov (United States)

    Sag, Alan A; Afsar, Baris; Kanbay, Mehmet

    2017-12-01

    Carbon dioxide angiography is an established non-nephrotoxic option for imaging of the infradiaphragmatic arteries and veins. Safe performance of the technique once required a somewhat cumbersome system, however, recent innovations have simplified implementation and expanded the user base for this technique. As such, patient access has also increased. In this issue, Hameed et al. provide initial feasibility data regarding carbon dioxide angiography and renal denervation therapy. This experience may be translated into future renovascular interventions in patients with limited renal reserve.

  10. 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. Copyright © 2015 John Wiley & Sons, Ltd.

  11. Combined multimodal photoacoustic tomography, optical coherence tomography (OCT) and OCT based angiography system for in vivo imaging of multiple skin disorders in human(Conference Presentation)

    Science.gov (United States)

    Liu, Mengyang; Chen, Zhe; Sinz, Christoph; Rank, Elisabet; Zabihian, Behrooz; Zhang, Edward Z.; Beard, Paul C.; Kittler, Harald; Drexler, Wolfgang

    2017-02-01

    All optical photoacoustic tomography (PAT) using a planar Fabry-Perot interferometer polymer film sensor has been demonstrated for in vivo human palm imaging with an imaging penetration depth of 5 mm. The relatively larger vessels in the superficial plexus and the vessels in the dermal plexus are visible in PAT. However, due to both resolution and sensitivity limits, all optical PAT cannot reveal the smaller vessels such as capillary loops and venules. Melanin absorption also sometimes causes difficulties in PAT to resolve vessels. Optical coherence tomography (OCT) based angiography, on the other hand, has been proven suitable for microvasculature visualization in the first couple millimeters in human. In our work, we combine an all optical PAT system with an OCT system featuring a phase stable akinetic swept source. This multimodal PAT/OCT/OCT-angiography system provides us co-registered human skin vasculature information as well as the structural information of cutaneous. The scanning units of the sub-systems are assembled into one probe, which is then mounted onto a portable rack. The probe and rack design gives six degrees of freedom, allowing the multimodal optical imaging probe to access nearly all regions of human body. Utilizing this probe, we perform imaging on patients with various skin disorders as well as on healthy controls. Fused PAT/OCT-angiography volume shows the complete blood vessel network in human skin, which is further embedded in the morphology provided by OCT. A comparison between the results from the disordered regions and the normal regions demonstrates the clinical translational value of this multimodal optical imaging system in dermatology.

  12. Development of new risk score for pre-test probability of obstructive coronary artery disease based on coronary CT angiography.

    Science.gov (United States)

    Fujimoto, Shinichiro; Kondo, Takeshi; Yamamoto, Hideya; Yokoyama, Naoyuki; Tarutani, Yasuhiro; Takamura, Kazuhisa; Urabe, Yoji; Konno, Kumiko; Nishizaki, Yuji; Shinozaki, Tomohiro; Kihara, Yasuki; Daida, Hiroyuki; Isshiki, Takaaki; Takase, Shinichi

    2015-09-01

    Existing methods to calculate pre-test probability of obstructive coronary artery disease (CAD) have been established using selected high-risk patients who were referred to conventional coronary angiography. The purpose of this study is to develop and validate our new method for pre-test probability of obstructive CAD using patients who underwent coronary CT angiography (CTA), which could be applicable to a wider range of patient population. Using consecutive 4137 patients with suspected CAD who underwent coronary CTA at our institution, a multivariate logistic regression model including clinical factors as covariates calculated the pre-test probability (K-score) of obstructive CAD determined by coronary CTA. The K-score was compared with the Duke clinical score using the area under the curve (AUC) for the receiver-operating characteristic curve. External validation was performed by an independent sample of 319 patients. The final model included eight significant predictors: age, gender, coronary risk factor (hypertension, diabetes mellitus, dyslipidemia, smoking), history of cerebral infarction, and chest symptom. The AUC of the K-score was significantly greater than that of the Duke clinical score for both derivation (0.736 vs. 0.699) and validation (0.714 vs. 0.688) data sets. Among patients who underwent coronary CTA, newly developed K-score had better pre-test prediction ability of obstructive CAD compared to Duke clinical score in Japanese population.

  13. CT angiography and magnetic resonance angiography findings after surgical and interventional radiology treatment of peripheral arterial obstructive disease

    NARCIS (Netherlands)

    Anzidei, Michele; Lucatelli, Pierleone; Napoli, Alessandro; Jens, Sjoerd; Saba, Luca; Cartocci, Gaia; Sedati, Pietro; d'Adamo, Alessandro; Catalano, Carlo

    2015-01-01

    In the last years, technical innovations in the field of CT angiography (CTA) and magnetic resonance angiography (MRA) have allowed accurate and highly detailed evaluation of peripheral vascular pathologies. This has dramatically changed the diagnostic approach in treatment planning of peripheral

  14. Complex-based OCT angiography algorithm recovers microvascular information better than amplitude- or phase-based algorithms in phase-stable systems

    Science.gov (United States)

    Xu, Jingjiang; Song, Shaozhen; Li, Yuandong; Wang, Ruikang K.

    2018-01-01

    Optical coherence tomography angiography (OCTA) is increasingly becoming a popular inspection tool for biomedical imaging applications. By exploring the amplitude, phase and complex information available in OCT signals, numerous algorithms have been proposed that contrast functional vessel networks within microcirculatory tissue beds. However, it is not clear which algorithm delivers optimal imaging performance. Here, we investigate systematically how amplitude and phase information have an impact on the OCTA imaging performance, to establish the relationship of amplitude and phase stability with OCT signal-to-noise ratio (SNR), time interval and particle dynamics. With either repeated A-scan or repeated B-scan imaging protocols, the amplitude noise increases with the increase of OCT SNR; however, the phase noise does the opposite, i.e. it increases with the decrease of OCT SNR. Coupled with experimental measurements, we utilize a simple Monte Carlo (MC) model to simulate the performance of amplitude-, phase- and complex-based algorithms for OCTA imaging, the results of which suggest that complex-based algorithms deliver the best performance when the phase noise is  animal models and human retina to verify the findings from the MC model through assessing the OCTA performance metrics of vessel connectivity, image SNR and contrast-to-noise ratio. We show that for all the metrics assessed, the complex-based algorithm delivers better performance than either the amplitude- or phase-based algorithms for both the repeated A-scan and the B-scan imaging protocols, which agrees well with the conclusion drawn from the MC simulations.

  15. Non-contrast-enhanced MR angiography in critical limb ischemia: performance of quiescent-interval single-shot (QISS) and TSE-based subtraction techniques

    International Nuclear Information System (INIS)

    Altaha, Mustafa A.; Jaskolka, Jeffrey D.; Tan, Kongteng; Menezes, Ravi J.; Rick, Manuela; Schmitt, Peter; Wintersperger, Bernd J.

    2017-01-01

    The aim of this study was to evaluate diagnostic performance of non-contrast-enhanced 2D quiescent-interval single-shot (QISS) and 3D turbo spin-echo (TSE)-based subtraction magnetic resonance angiography (MRA) in the assessment of peripheral arteries in patients with critical limb ischemia (CLI). Nineteen consecutive patients (74 % male, 72.8 ± 9.9 years) with CLI underwent 2D QISS and 3D TSE-based subtraction MRA at 1.5 T. Axial-overlapping QISS MRA (3 mm/2 mm; 1 x 1 mm 2 ) covered from the toes to the aortic bifurcation while coronal 3D TSE-based subtraction MRA (1.3 x 1.2 x 1.3 mm 3 ) was restricted to the calf only. MRA data sets (two readers) were evaluated for stenosis (≥50 %) and image quality. Results were compared with digital subtraction angiography (DSA). Two hundred and sixty-seven (267) segments were available for MRA-DSA comparison, with a prevalence of stenosis ≥50 % of 41.9 %. QISS MRA was rated as good to excellent in 79.5-96.0 % of segments without any nondiagnostic segments; 89.8-96.1 % of segments in 3D TSE-based subtraction MRA were rated as nondiagnostic or poor. QISS MRA sensitivities and specificities (segmental) were 92 % and 95 %, respectively, for reader one and 81-97 % for reader two. Due to poor image quality of 3D TSE-based subtraction MRA, diagnostic performance measures were not calculated. QISS MRA demonstrates excellent diagnostic performance and higher robustness than 3D TSE-based subtraction MRA in the challenging patient population with CLI. (orig.)

  16. Non-contrast-enhanced MR angiography in critical limb ischemia: performance of quiescent-interval single-shot (QISS) and TSE-based subtraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Altaha, Mustafa A. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); Jaskolka, Jeffrey D.; Tan, Kongteng; Menezes, Ravi J. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); University of Toronto, Department of Medical Imaging, Toronto, Ontario (Canada); Rick, Manuela; Schmitt, Peter [Siemens Healthcare, Erlangen (Germany); Wintersperger, Bernd J. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); University of Toronto, Department of Medical Imaging, Toronto, Ontario (Canada); Toronto General Hospital, Department of Medical Imaging, Toronto, Ontario (Canada)

    2017-03-15

    The aim of this study was to evaluate diagnostic performance of non-contrast-enhanced 2D quiescent-interval single-shot (QISS) and 3D turbo spin-echo (TSE)-based subtraction magnetic resonance angiography (MRA) in the assessment of peripheral arteries in patients with critical limb ischemia (CLI). Nineteen consecutive patients (74 % male, 72.8 ± 9.9 years) with CLI underwent 2D QISS and 3D TSE-based subtraction MRA at 1.5 T. Axial-overlapping QISS MRA (3 mm/2 mm; 1 x 1 mm{sup 2}) covered from the toes to the aortic bifurcation while coronal 3D TSE-based subtraction MRA (1.3 x 1.2 x 1.3 mm{sup 3}) was restricted to the calf only. MRA data sets (two readers) were evaluated for stenosis (≥50 %) and image quality. Results were compared with digital subtraction angiography (DSA). Two hundred and sixty-seven (267) segments were available for MRA-DSA comparison, with a prevalence of stenosis ≥50 % of 41.9 %. QISS MRA was rated as good to excellent in 79.5-96.0 % of segments without any nondiagnostic segments; 89.8-96.1 % of segments in 3D TSE-based subtraction MRA were rated as nondiagnostic or poor. QISS MRA sensitivities and specificities (segmental) were 92 % and 95 %, respectively, for reader one and 81-97 % for reader two. Due to poor image quality of 3D TSE-based subtraction MRA, diagnostic performance measures were not calculated. QISS MRA demonstrates excellent diagnostic performance and higher robustness than 3D TSE-based subtraction MRA in the challenging patient population with CLI. (orig.)

  17. Using decision trees for measuring gender equity in the timing of angiography in patients with acute coronary syndrome: a novel approach to equity analysis.

    Science.gov (United States)

    Bierman, Arlene S; Brown, Adalsteinn D; Levinton, Carey M

    2015-12-23

    Methods to measure or quantify equity in health care remain scarce, if not difficult to interpret. A novel method to measure health equity is presented, applied to gender health equity, and illustrated with an example of timing of angiography in patients following a hospital admission for an acute coronary syndrome. Linked administrative hospital discharge and survey data was used to identify a retrospective cohort of patients hospitalized with Acute Coronary Syndrome (ACS) between 2002 and 2008 who also responded to the Canadian Community Health Survey (CCHS), was analyzed using decision trees to determine whether gender impacted the delay to angiography following an ACS. Defining a delay to angiography as 1 day or more, resulted in a non-significant difference in an equity score of 0.14 for women and 0.12 for men, where 0 and 1 represents perfect equity and inequity respectively. Using 2 and 3 day delays as a secondary outcome resulted in women and men producing scores of 0.19 and 0.17 for a 2 day delay and 0.22 and 0.23 for a 3 day delay. A technique developed expressly for measuring equity suggests that men and women in Ontario receive equitable care in access to angiography with respect to timeliness following an ACS.

  18. Influence of heart rate on diagnostic accuracy and image quality of 16-slice CT coronary angiography: comparison of multisegment and halfscan reconstruction approaches

    International Nuclear Information System (INIS)

    Dewey, Marc; Teige, Florian; Hamm, Bernd; Laule, Michael

    2007-01-01

    The lower the heart rate the better image quality in multislice computed tomography (MSCT) coronary angiography. We prospectively assessed the influence of heart rate on per-patient diagnostic accuracy and image quality of MSCT coronary angiography and compared adaptive multisegment and standard halfscan reconstruction. A consecutive cohort of 126 patients scheduled to undergo conventional coronary angiography was examined with 16-slice CT. For all heart rate groups, per-patient diagnostic accuracy was significantly higher for multisegment than halfscan reconstruction with values of 95 vs. 79% (p 74 bpm, 41 patients). Differences in diagnostic accuracy between adjacent heart rate groups were only significant for halfscan reconstruction for the comparison between the 65-74 and >74 bpm group (p < 0.05). The vessel lengths free of motion artifacts were significantly longer with multisegment reconstruction in all heart rate groups and for all coronary arteries (p < 0.005). For noninvasive MSCT coronary angiography, both per-patient diagnostic accuracy and image quality decline with increasing heart rate, and multisegment reconstruction at high heart rates yields similar results as standard halfscan reconstruction at low heart rates. (orig.)

  19. Digital subtraction angiography (DSA)

    International Nuclear Information System (INIS)

    Lackner, K.; Janson, R.; Franken, T.; Harder, T.; Thurn, P.

    1983-01-01

    Digital subtraction angiography is an advanced subtraction technique and a new field in which i.v. injection of contrast media is required. Conventional techniques involving i.v. injection of contrast media have the following drawbacks: 1. High amounts of contrast media; 2. simultaneous injection into the brachial veins of both arms; 3. poor imaging of blood vessels in regions with strongly varying X-ray absorption characteristics of the background; 4. no possibility of contrast amplification. In conventional subtraction techniques, image processing takes place as a second step after the examination, so that results are not immediately available for interpretation. Digital subtraction angiography largely avoids these drawbacks. (orig./MG) [de

  20. 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.

  1. Angiography in renal diagnostics

    International Nuclear Information System (INIS)

    Schreyer, H.; Justich, E.; Graz Univ.

    1982-01-01

    The angiographic symptoms of kidney vessels diseases are described as well as traumas and growing and displacing processes of the kidneys. The diagnostic value of angiography in kidney traumas and growing and displacing processes of the kidney is discussed and compared with other techniques, e.g. urography, sonography and computed tomography. (orig.) [de

  2. iPad-based primary 2D reading of CT angiography examinations of patients with suspected acute gastrointestinal bleeding: preliminary experience.

    Science.gov (United States)

    Faggioni, L; Neri, E; Bargellini, I; Scalise, P; Calcagni, F; Mantarro, A; D'Ippolito, G; Bartolozzi, C

    2015-03-01

    To evaluate the effectiveness of the iPad (Apple Inc., Cupertino, CA) for two-dimensional (2D) reading of CT angiography (CTA) studies performed for suspected acute non-variceal gastrointestinal bleeding. 24 CTA examinations of patients with suspected acute gastrointestinal bleeding confirmed (19/24, 79.2%) or ruled out (5/24, 20.8%) by digital subtraction angiography (DSA) were retrospectively reviewed by three independent readers on a commercial picture archiving communication system (PACS) workstation and on an iPad with Retina Display® 64 GB (Apple Inc.). The time needed to complete reading of every CTA examination was recorded, as well as the rate of detection of arterial bleeding and identification of suspected bleeding arteries on both devices. Overall, the area under the receiver operating characteristic curve, sensitivity, specificity, positive- and negative-predictive values for bleeding detection were not significantly different while using the iPad and workstation (0.774 vs 0.847, 0.947 vs 0.895, 0.6 vs 0.8, 0.9 vs 0.944 and 0.750 vs 0.667, respectively; p > 0.05). In DSA-positive cases, the iPad and workstation allowed correct identification of the bleeding source in 17/19 cases (89.5%) and 15/19 cases (78.9%), respectively (p > 0.05). Finally, the time needed to complete reading of every CTA study was significantly shorter using the iPad (169 ± 74 vs 222 ± 70 s, respectively; p iPad-based preliminary 2D reading of CTA studies has comparable diagnostic accuracy for detection of acute gastrointestinal bleeding and can be significantly faster. The iPad could be used by on-call interventional radiologists for immediate decision on percutaneous embolization in patients with suspected acute gastrointestinal bleeding.

  3. MR angiography of lower extremity

    International Nuclear Information System (INIS)

    Fujikawa, Takao

    1991-01-01

    MR angiography by ECG-gated 2D rephase-dephase subtraction method was performed in normal volunteers (n=14) and patients with arterial or venous vascular disease of lower extremities (n=36). Results were compared to digital subtraction angiography or conventional film angiography. In normal cases, superficial femoral and popliteal arteries were well demonstrated by angiography whereas visualization of intrapelvic portion of the arteries was often impaired by mortion artifacts from bowel loops. Diagnostic results of MR angiography and digital or conventional angiography were in agreement in 92.3% of obstructive arteriosclerotic disease, 87.0% of post by-pass graft surgery, and 85.7% of cases in which deep vein thrombosis was clinically suspected. Considering its virtually noninvasive nature, MR angiography can be a valuable screening method in vascular diseases of lower extremities and also in post operative evaluation of by-pass graft surgery. Further technical advancements are expected. (author)

  4. MR angiography of lower extremity

    Energy Technology Data Exchange (ETDEWEB)

    Fujikawa, Takao (Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine)

    1991-02-01

    MR angiography by ECG-gated 2D rephase-dephase subtraction method was performed in normal volunteers (n=14) and patients with arterial or venous vascular disease of lower extremities (n=36). Results were compared to digital subtraction angiography or conventional film angiography. In normal cases, superficial femoral and popliteal arteries were well demonstrated by angiography whereas visualization of intrapelvic portion of the arteries was often impaired by mortion artifacts from bowel loops. Diagnostic results of MR angiography and digital or conventional angiography were in agreement in 92.3% of obstructive arteriosclerotic disease, 87.0% of post by-pass graft surgery, and 85.7% of cases in which deep vein thrombosis was clinically suspected. Considering its virtually noninvasive nature, MR angiography can be a valuable screening method in vascular diseases of lower extremities and also in post operative evaluation of by-pass graft surgery. Further technical advancements are expected. (author).

  5. Fast carotid artery MR angiography with compressed sensing based three-dimensional time-of-flight sequence.

    Science.gov (United States)

    Li, Bo; Li, Hao; Dong, Li; Huang, Guofu

    2017-11-01

    In this study, we sought to investigate the feasibility of fast carotid artery MR angiography (MRA) by combining three-dimensional time-of-flight (3D TOF) with compressed sensing method (CS-3D TOF). A pseudo-sequential phase encoding order was developed for CS-3D TOF to generate hyper-intense vessel and suppress background tissues in under-sampled 3D k-space. Seven healthy volunteers and one patient with carotid artery stenosis were recruited for this study. Five sequential CS-3D TOF scans were implemented at 1, 2, 3, 4 and 5-fold acceleration factors for carotid artery MRA. Blood signal-to-tissue ratio (BTR) values for fully-sampled and under-sampled acquisitions were calculated and compared in seven subjects. Blood area (BA) was measured and compared between fully sampled acquisition and each under-sampled one. There were no significant differences between the fully-sampled dataset and each under-sampled in BTR comparisons (P>0.05 for all comparisons). The carotid vessel BAs measured from the images of CS-3D TOF sequences with 2, 3, 4 and 5-fold acceleration scans were all highly correlated with that of the fully-sampled acquisition. The contrast between blood vessels and background tissues of the images at 2 to 5-fold acceleration is comparable to that of fully sampled images. The images at 2× to 5× exhibit the comparable lumen definition to the corresponding images at 1×. By combining the pseudo-sequential phase encoding order, CS reconstruction, and 3D TOF sequence, this technique provides excellent visualizations for carotid vessel and calcifications in a short scan time. It has the potential to be integrated into current multiple blood contrast imaging protocol. Copyright © 2017. Published by Elsevier Inc.

  6. Magnetic resonance angiography in meningovascular syphilis

    International Nuclear Information System (INIS)

    Gallego, J.; Soriano, G.; Zubieta, J.L.; Delgado, G.; Villanueva, J.A.

    1994-01-01

    Meningovascular neurosyphilis (MN) is an unusual cause of stroke in young adults. The clinical manifestations include prodromal symptoms weeks or months before definitive stroke. The diagnosis is based on clinical findings and examination of the serum and cerebrospinal fluid. We report a case of MN with basilar artery irregularities demonstrated by magnetic resonance angiography. (orig.)

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

    International Nuclear Information System (INIS)

    Kang Deqiang; Zhao Jing; Peng Nan; Hua Haiqin; Li Chao; Guo Ying; Shen Yun

    2012-01-01

    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/m 2 ≤ BMI < 25.0 kg/m 2 ), and 500-800 mA (BMI ≥ 25.0 kg/m 2 ). 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 (CTDI vol ) [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)

  8. 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.

  9. 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.)

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

    International Nuclear Information System (INIS)

    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.

    2016-01-01

    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 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 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 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.)

  11. Detection of single-phase CTA occult vessel occlusions in acute ischemic stroke using CT perfusion-based wavelet-transformed angiography

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, Wolfgang G.; Sommer, Wieland H.; Meinel, Felix G.; Ertl-Wagner, Birgit; Thierfelder, Kolja M. [Ludwig-Maximilian-University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); Havla, Lukas; Dietrich, Olaf [Ludwig-Maximilian-University Hospital Munich, Josef Lissner Laboratory for Biomedical Imaging of the Institute for Clinical Radiology, Munich (Germany); Dorn, Franziska [Ludwig-Maximilian-University Hospital Munich, Department of Neuroradiology, Munich (Germany); Buchholz, Grete [Ludwig-Maximilian-University Hospital Munich, Department of Neurology, Munich (Germany)

    2017-06-15

    To determine the detection rate of intracranial vessel occlusions using CT perfusion-based wavelet-transformed angiography (waveletCTA) in acute ischemic stroke patients, in whom single-phase CTA (spCTA) failed to detect an occlusion. Subjects were selected from a cohort of 791 consecutive patients who underwent multiparametric CT including whole-brain CT perfusion. Inclusion criteria were (1) significant cerebral blood flow (CBF) deficit, (2) no evidence of vessel occlusion on spCTA and (3) follow-up-confirmed acute ischemic infarction. waveletCTA was independently analysed by two readers regarding presence and location of vessel occlusions. Logistic regression analysis was performed to identify predictors of waveletCTA-detected occlusions. Fifty-nine patients fulfilled the inclusion criteria. Overall, an occlusion was identified using waveletCTA in 31 (52.5 %) patients with negative spCTA. Out of 47 patients with middle cerebral artery infarction, 27 occlusions (57.4 %) were detected by waveletCTA, mainly located in the M2 (15) and M3 segments (8). The presence of waveletCTA-detected occlusions was associated with larger CBF deficit volumes (odds ratio (OR) = 1.335, p = 0.010) and shorter times from symptom onset (OR = 0.306, p = 0.041). waveletCTA is able to detect spCTA occult vessel occlusions in about half of acute ischemic stroke patients and may potentially identify more patients eligible for endovascular therapy. (orig.)

  12. Assessment of Left Ventricular Function and Volume in Patients Undergoing 128-Slice Coronary CT Angiography with ECG-Based Maximum Tube Current Modulation: a Comparison with Echocardiography

    International Nuclear Information System (INIS)

    Lim, Soo Jin; Choo, Ki Seok; Park, Yong Hyun; Kim, Jeong Su; Kim, June Hong; Chun, Kook Jin; Jeong, Dong Wook

    2011-01-01

    To compare multi-detector CT (MDCT) using 128-slice coronary CT angiography (Definition AS+, Siemens Medical Solution, Forchheim, Germany) with ECG-based maximum tube current modulation with echocardiography for the determination of left ventricular ejection fraction (LVEF), end-diastolic volume (EDV), end-systolic volume (ESV), as well as assessing coronary artery image quality and patient radiation dose. Thirty consecutive patients (M:F = 20:10: mean age, 57.9 ± 11.4 years) were referred for MDCT for evaluation of atypical chest pain. EF, EDV and ESV were determined for both MDCT and echocardiography, and the correlation coefficients were assessed. Coronary artery segment subjective image quality (1, excellent: 4, poor) and radiation dose were recorded. Left ventricular EF, EDV, and ESV were calculated by MDCT and echocardiography and the comparison showed a significant correlation with those estimated by echocardiography (p < 0.05). Consistently, the LVEFs calculated by MDCT and echocardiography were not statistically different. However, LV, EDV and ESV from MDCT were statistically higher than those from echocardiography (p < 0.05). The average image quality score of the coronary artery segment was 1.10 and the mean patient radiation dose was 3.99 ± 1.85 mSv. Although LV volume was overestimated by MDCT, MDCT provides comparable results to echocardiography for LVEF and LVV, with a low radiation dose

  13. Intraarterial digital subtraction angiography

    International Nuclear Information System (INIS)

    Davis, P.C.

    1987-01-01

    Digital subtraction angiography (DSA) refers to a radiographic technique of amplifying low levels of contrast from intravascular iodine into an acceptable image of vascular anatomy. Initial enthusiasm suggested that DSA using intravenous injections (IV-DSA) would eliminate most conventional film-screen angiographic studies. It was soon apparent, however, that IV-DSA examinations were often compromised in those patients who most needed a less invasive study. Indeed, only a 70 to 85 percent accuracy rate was achieved with IV-DSA, primarily due to motion artifact, poor cardiac output, overlap of pertinent vessels, and inability to resolve smaller vessels

  14. Digital angiography and surgery in the same room

    International Nuclear Information System (INIS)

    Goldman, M.L.; Hack, S.N.; Sarrafizadeh, M.S.; Marar, H.G.; Behar, D.J.; Chigurupati, R.C.; Klein, S.I.; Widlus, D.M.; Fortune, J.B.

    1986-01-01

    Albany Medical Center and private industries (XRE and United X-ray corporations) have collaborated to develop a room within the operating suite that allows high-speed and high-resolution digital angiography and surgery to be performed simultaneously. Patients who have sustained massive trauma can be transferred directly from the ambulance to this new facility. While the patient is undergoing exploratory laparotomy, other vital areas of the body can be evaluated by angiography. This combined approach of surgery and angiography has also led to improved management of patients with massive or occult intestinal hemorrhage and patients with peripheral vascular disease. Other patients undergoing difficult emergency or elective surgery, as in the biliary tract, can now have available the benefits of an operating room facility that also allows high-resolution fluoroscopy and complete angiography to be undertaken

  15. Usefulness of MR angiography in renal tumor

    International Nuclear Information System (INIS)

    Oka, Toshitsugu; Morimoto, Kouji; Nishimura, Kenji; Tsujimura, Akira; Yasunaga, Yutaka; Matsumiya, Kiyomi; Takaha, Minato

    1992-01-01

    MR angiography using a gradient-echo, pulse sequence FLASH (fast, low-angle shot) method during breath-hold with a 'MAGNETOM H-15' scanner (1.5 Tesla; Siemens Medical System) was performed on 27 patients with renal tumor at our clinic between Feburary 20, 1990 and September 30, 1991 and we studied to evaluate its usefulness. Of these 27 patients, 22 patients including one patient under hemodialysis treatment had renal cell carcinoma and one patient had oncocytoma pathologically proven from the excised specimens. The remaining four patients including two patients associated with inferior vena cava tumor thrombus were clinically diagnosed as renal cell carcinoma based on the result of imaging examinations such as excretory urography, ultrasonography, computed tomography and conventional angiography. However, they could not be operated on because their tumors were too advanced. By reconstruction of the data of consecutive coronal scans of the abdominal blood vessels such as the abdominal aorta, inferior vena cava and renal arteries and veins simultaneously without any intravenous contrast materials. Our present study revealed that MR angiography has some advantages, especially with regard to preoperative angiographic information about the abdomen of patients with renal tumor. That is, MR angiography can delineate many kinds of arteries and veins of the abdomen simultaneously and in a broader range, as well as it can be performed on the patients with hypersensitivity to iodinate contrast materials or renal insufficiency in a usual fashion. Furthermore, our present study suggested that the MR angiography is useful for assessing the presence and extent of inferior vena caval tumor thrombus of renal cell carcinoma and for clearly distinguishing tumor lesion and the surrounding normal renal parenchyma in the patients with renal tumor. (author)

  16. Segmentation of brain magnetic resonance angiography images based on MAP-MRF with multi-pattern neighborhood system and approximation of regularization coefficient.

    Science.gov (United States)

    Zhou, Shoujun; Chen, Wufan; Jia, Fucang; Hu, Qingmao; Xie, Yaoqin; Chen, Mingyang; Wu, Jianhuang

    2013-12-01

    Existing maximum a posteriori probability and Markov random field (MRF) models have limitations associated with: (1) the ordinary neighborhood system being unable to differentiate subtle changes due to several-to-one correspondence within the neighborhood; and (2) difficulty finding an appropriate parameter to balance between the spatial context and the data likelihood. Aiming at overcoming the limitations and applications to segmentation of cerebral vessels from magnetic resonance angiography images, we have proposed (1) a multi-pattern neighborhood system and corresponding energy equation to enable the MRF model for segmenting fine cerebral vessels with complicated context; and (2) an iterative approximation algorithm based on the maximum pseudo-likelihood and the space coding mode for the automatic parameter estimation of high level model of MRF. In the implementation, two computational strategies have been employed to speed up: the candidate space of cerebral vessels based on a threshold of the response to multi-scale filtering, and parallel computation of major equations. Three phantoms simulating segmentation challenges of vessels have been devised to quantitatively validate the algorithm. In addition, 10 three-dimensional clinical data sets have been used to validate the algorithm qualitatively. It has been shown that the proposed method could yield smaller error, improve the spatial resolution of MRF model, and better balance the smoothing and data likelihood than the traditional trial-and-error estimation. Comparative studies have shown that the proposed method is better than the 3 segmentation algorithms (Hassouna et al., 2006; Hao et al., 2008; Gao et al., 2011) in terms of segmentation accuracy, robustness to noise and varying curvatures as well as radii. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Diagnostic value of multislice computed tomography angiography in coronary artery disease: A meta-analysis

    International Nuclear Information System (INIS)

    Sun Zhonghua; Jiang Wen

    2006-01-01

    Purpose: To perform a meta-analysis of the diagnostic value of 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 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 analyzed at segment-, vessel- and patient-based assessment. Results: 47 studies (67 comparisons) met the criteria and were included in our study. Pooled overall sensitivity, specificity and 95% confidence interval for MSCT angiography in the detection of CAD were 83% (79%, 89%), 93% (91%, 96%) at segment-based analysis; 90% (87%, 94%), 87% (80%, 93%) at vessel-based analysis; and 91% (88%, 95%), 86% (81%, 92%) at patient-based analysis, respectively. Diagnostic accuracy of MSCT angiography in evaluating assessable segments was significantly improved with 64-slice scanners when compared to that with 4- and 16-slice scanners (p < 0.05). Conclusion: Our meta-analysis showed that MSCT angiography has potential diagnostic accuracy in the detection of CAD. Diagnostic performance of MSCT angiography has been significantly improved with the latest 64-slice CT, with resultant high qualitative and quantitative diagnostic accuracy. 16-slice CT was limited in spatial resolution which makes it difficult to perform quantitative assessment of coronary artery stenoses

  18. Coronary CT angiography and MR angiography of Kawasaki disease

    International Nuclear Information System (INIS)

    Goo, Hyun Woo; Park, In-Sook; Ko, Jae Kon; Kim, Young Hwee

    2006-01-01

    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.)

  19. Coronary Computed Tomographic Angiography-Dekived Fractional Flow Reserve Based on Machine Learning for Risk Stratification of Non-Culprit Coronary Narrowings in Patients with Acute Coronary Syndrome

    NARCIS (Netherlands)

    Duguay, Taylor M.; Tesche, Christian; Vliegenthart, Rozemarijn; De Cecco, Carlo N.; Lin, Han; Albrecht, Moritz H.; Varga-Szemes, Akos; De Santis, Domenico; Ebersberger, Ullrich; Bayer, Richard R.; Litwin, Sheldon E.; Hoffmann, Ellen; Steinberg, Daniel H.; Schoepf, U. Joseph

    2017-01-01

    This study investigated the prognostic value of coronary computed tomography angiography (cCTA)-derived fractional flow reserve (CT-FFR) in patients with acute coronary syndrome (ACS) and multivessel disease to gauge significance and guide management of non-culprit lesions. We retrospectively

  20. Vascular diameter measurement in CT angiography: comparison of model-based iterative reconstruction and standard filtered back projection algorithms in vitro.

    Science.gov (United States)

    Suzuki, Shigeru; Machida, Haruhiko; Tanaka, Isao; Ueno, Eiko

    2013-03-01

    The purpose of this study was to evaluate the performance of model-based iterative reconstruction (MBIR) in measurement of the inner diameter of models of blood vessels and compare performance between MBIR and a standard filtered back projection (FBP) algorithm. Vascular models with wall thicknesses of 0.5, 1.0, and 1.5 mm were scanned with a 64-MDCT unit and densities of contrast material yielding 275, 396, and 542 HU. Images were reconstructed images by MBIR and FBP, and the mean diameter of each model vessel was measured by software automation. Twenty separate measurements were repeated for each vessel, and variance among the repeated measures was analyzed for determination of measurement error. For all nine model vessels, CT attenuation profiles were compared along a line passing through the luminal center on axial images reconstructed with FBP and MBIR, and the 10-90% edge rise distances at the boundary between the vascular wall and the lumen were evaluated. For images reconstructed with FBP, measurement errors were smallest for models with 1.5-mm wall thickness, except those filled with 275-HU contrast material, and errors grew as the density of the contrast material decreased. Measurement errors with MBIR were comparable to or less than those with FBP. In CT attenuation profiles of images reconstructed with MBIR, the 10-90% edge rise distances at the boundary between the lumen and vascular wall were relatively short for each vascular model compared with those of the profile curves of FBP images. MBIR is better than standard FBP for reducing reconstruction blur and improving the accuracy of diameter measurement at CT angiography.

  1. Regional Mapping of Aortic Wall Stress by Using Deformable, Motion-coherent Modeling based on Electrocardiography-gated Multidetector CT Angiography: Feasibility Study.

    Science.gov (United States)

    Mileto, Achille; Heye, Tobias J; Makar, Ryan A; Hurwitz, Lynne M; Marin, Daniele; Boll, Daniel T

    2016-07-01

    Purpose To investigate the feasibility of deformable, motion-coherent modeling based on electrocardiography-gated multidetector computed tomographic (CT) angiography of the thoracic aorta and to evaluate whether quantifiable information on aortic wall stress as a function of patient-specific cardiovascular parameters can be gained. Materials and Methods For this institutional review board-approved, HIPAA-compliant study, thoracic electrocardiography-gated dual-source multidetector CT angiographic images were used from 250 prospectively enrolled patients (150 men, 100 women; mean age, 79 years). On reconstructed 50-phase CT angiographic images, aortic strain and deformation were determined at seven cardiac and aortic locations. One-way analysis of variance was used by assessing the magnitude for longitudinal and axial strain and axial deformation, as well as time-resolved peak and maxima count for longitudinal strain and axial deformation. Interdependencies between aortic strain and deformation with extracted hemodynamic parameters were evaluated. Results With increasing heart rates, there was a significant decrease in longitudinal strain (P = .009, R(2) = 0.95) and a decrease in the number of longitudinal strain peaks (P < .001, R(2) = 0.79); however, a significant increase in axial deformation (P < .001, R(2) = 0.31) and axial strain (P = .009, R(2) = 0.61) was observed. Increasing aortic blood velocity led to increased longitudinal strain (P = .018, R(2) = 0.42) and longitudinal strain peak counts (P = .011, R(2) = 0.48). Pronounced motion in the longitudinal direction limited motion in the axial plane (P < .019, R(2) = 0.29-0.31). Conclusion The results of this study render a clinical basis and provide proof of principle for the use of deformable, motion-coherent modeling to provide quantitative information on physiological motion of the aorta under various hemodynamic circumstances. (©) RSNA, 2016 Online supplemental material is available for this article.

  2. 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.

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

    Science.gov (United States)

    Schwarz, Florian; Lange, Philipp; Zinsser, Dominik; Greif, Martin; Boekstegers, Peter; Schmitz, Christoph; Reiser, Maximilian F; Kupatt, Christian; Becker, Hans C

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Florian Schwarz

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

  5. Reduction of metal artifacts due to dental hardware in computed tomography angiography: assessment of the utility of model-based iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Kuya, Keita; Shinohara, Yuki; Ogawa, Toshihide [Tottori University, Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Yonago (Japan); Kato, Ayumi [Tottori Municipal Hospital, Department of Radiology, Yonago (Japan); Sakamoto, Makoto; Kurosaki, Masamichi [Tottori University, Division of Neurosurgery, Department of Neurological Sciences, Faculty of Medicine, Yonago (Japan)

    2017-03-15

    The aim of this study is to assess the value of adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) for reduction of metal artifacts due to dental hardware in carotid CT angiography (CTA). Thirty-seven patients with dental hardware who underwent carotid CTA were included. CTA was performed with a GE Discovery CT750 HD scanner and reconstructed with filtered back projection (FBP), ASIR, and MBIR. We measured the standard deviation at the cervical segment of the internal carotid artery that was affected most by dental metal artifacts (SD{sub 1}) and the standard deviation at the common carotid artery that was not affected by the artifact (SD{sub 2}). We calculated the artifact index (AI) as follows: AI = [(SD{sub 1})2 - (SD{sub 2})2]1/2 and compared each AI for FBP, ASIR, and MBIR. Visual assessment of the internal carotid artery was also performed by two neuroradiologists using a five-point scale for each axial and reconstructed sagittal image. The inter-observer agreement was analyzed using weighted kappa analysis. MBIR significantly improved AI compared with FBP and ASIR (p < 0.001, each). We found no significant difference in AI between FBP and ASIR (p = 0.502). The visual score of MBIR was significantly better than those of FBP and ASIR (p < 0.001, each), whereas the scores of ASIR were the same as those of FBP. Kappa values indicated good inter-observer agreements in all reconstructed images (0.747-0.778). MBIR resulted in a significant reduction in artifact from dental hardware in carotid CTA. (orig.)

  6. 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

    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. 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). 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). Identification of collaterals based on CGS may help to select good responders to reperfusion therapy in patients with large artery occlusion.

  7. Kawasaki disease-associated coronary artery lesions with navigator echo-based. Respiratory-gated three dimensional coronary magnetic resonance angiography compared with echocardiography in young children

    International Nuclear Information System (INIS)

    Amino, Masayuki; Teraoka, Kunihiko; Hirano, Masaharu; Kawashima, Naoshi; Kakizaki, Dai; Ookubo, Yasuo; Sasaki, Kazuyoshi; Katuyama, Hiroaki

    2004-01-01

    Navigator echo-based respiratory-gated three dimensional coronary magnetic resonance angiography (3D-CMRA) was compared with echocardiography, to determine whether 3D-CMRA was useful for the evaluation of Kawasaki disease-associated coronary artery lesions. Sixteen consecutive patients (imaging was performed 17 times in total) who were given a diagnosis of Kawasaki's disease at the pediatric department of our hospital and examined for the precise examination of complicating coronary artery lesions on MRI using a navigator-echo technique because of their incapability of holding their breath during imaging were entered into the present study. A 1.5T MRI system was used. Gd-DOTA was given at a total volume of 0.1 mmol/kg. During imaging, CMRA visualized the left coronary arteries in all 17 cases and the right coronary arteries in 16 cases, but not in one case. The left main coronary trunk segment no.5 was demonstrated in all cases with CMRA, but not in 4 cases with echocardiography. The left anterior descending branch no.6 was visualized in 11 of the 17 cases with CMRA, but only in 5 cases with echocardiography. The left circumflex branch no.11 was observed in 6 cases with CMRA, but only in 2 cases with echocardiography. As for the right coronary arteries, branches no.1 and no.2 were observed in 16 and 9 cases with CMRA, respectively, and in 13 and 3 cases with echocardiography, respectively. Vascular diameters measured on CMRA were almost identical to those on echocardiography, within the range of arteries visualized. 3D-CMRA combined with a navigator echo technique appears to be a useful tool for the observation of coronary artery lesions associated with Kawasaki's disease because it is superior in lesion visualization to echocardiography. (author)

  8. Impact of window setting optimization on accuracy of computed tomography and computed tomography angiography source image-based Alberta Stroke Program Early Computed Tomography Score.

    Science.gov (United States)

    Arsava, Ethem Murat; Saarinen, Jukka T; Unal, Ali; Akpinar, Erhan; Oguz, Kader K; Topcuoglu, Mehmet Akif

    2014-01-01

    The use of narrower window width settings on computed tomography (CT) improves sensitivity for detection of early ischemic changes in acute ischemic stroke. This study analyzed the effect of optimization of window settings on the accuracy of Alberta Stroke Program Early Computed Tomography Score (ASPECTS) performed on noncontrast CT (NCCT) and CT angiography source images (CTA-SI). ASPECTS was calculated on NCCT and CTA-SI with standard and optimized window width/center settings in a consecutive series of patients with acute ishcemic stroke. The difference between CT-based ASPECTS and ASPECTS performed on follow-up magnetic resonance imaging (MRI) were calculated to determine the disparity between initial estimates of the extent of ischemia on CT and follow-up lesion imaging by MRI. Forty-four patients were included into the study. The mean difference with respect to follow-up MRI-ASPECTS was 4.1 ± 2.2 for standard NCCT-ASPECTS, 3.7 ± 2.3 for optimized NCCT-ASPECTS, 3.0 ± 2.2 for standard CTA-SI-ASPECTS, and 2.7 ± 2.1 for optimized CTA-SI-ASPECTS. The improvement introduced by the optimization of window settings and use of CTA-SI was statistically significant (P window display settings. This improvement is irrespective of experience or specialty of the rater performing the assessment. Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  9. Relationship of the sinus anatomy to surface landmarks is a function of the sinus size difference between the right and left side: Anatomical study based on CT angiography.

    Science.gov (United States)

    Hwang, Roy S; Turner, Ryan C; Radwan, Walid; Singh, Rahul; Lucke-Wold, Brandon; Tarabishy, Abdul; Bhatia, Sanjay

    2017-01-01

    Several cadaveric studies demonstrate reliable localization of the transverse sinus and the transverse sigmoid junction (TSJ). These studies use the line drawn from the inion to the posterior root of the zygoma (IZ) and the asterion, respectively. We investigated how the size difference between the right and left transverse sinuses (TS) and sigmoid sinuses (SS) affected the accuracy of their respective superficial landmarks, particularly with regards to where this relationship may result in unsafe and/or complicated surgical access. We utilized Vitrea software to render three-dimensional images based on computed tomographic angiography (CTA). We measured the relationship between the TS and SS to their respective superficial landmarks. We analyzed 50 patients in this study. The distal TS was found caudal to the inion-to-zygoma (IZ) line on average by 5.0 ± 4.3 mm on the right and 6.4 ± 9.3 mm on the left. The mid TS was found cranial on average 3.5 ± 5.7 mm on the right and 3.2 ± 6.0 mm cranial on the left to the superior nuchal line (SNL). The distance from the asterion to the SS was 11.5 ± 2.4 mm medial on the right and 12.1 ± 4.4 mm medial on the left. The average distance was greater on the left than the right when using the IZ landmark. This was directly proportional to the size difference of the sinuses ( r 2 = 0.15, P = 0.03). Statistically significant differences between the right and left TS and SS were seen in terms of size. This appeared to correlate nicely to the differences observed between the locations of the TSs' and their respective superficial landmarks.

  10. Feasibility Study of Computational Fluid Dynamics Simulation of Coronary Computed Tomography Angiography Based on Dual-Source Computed Tomography.

    Science.gov (United States)

    Lu, Jing; Yu, Jie; Shi, Heshui

    2017-01-01

    Adding functional features to morphological features offers a new method for non-invasive assessment of myocardial perfusion. This study aimed to explore technical routes of assessing the left coronary artery pressure gradient, wall shear stress distribution and blood flow velocity distribution, combining three-dimensional coronary model which was based on high resolution dual-source computed tomography (CT) with computational fluid dynamics (CFD) simulation. Three cases of no obvious stenosis, mild stenosis and severe stenosis in left anterior descending (LAD) were enrolled. Images acquired on dual-source CT were input into software Mimics, ICEMCFD and FLUENT to simulate pressure gradient, wall shear stress distribution and blood flow velocity distribution. Measuring coronary enhancement ratio of coronary artery was to compare with pressure gradient. Results conformed to theoretical values and showed difference between normal and abnormal samples. The study verified essential parameters and basic techniques in blood flow numerical simulation preliminarily. It was proved feasible.

  11. Computer-aided diagnosis of acute ischemic stroke based on cerebral hypoperfusion using 4D CT angiography

    Science.gov (United States)

    Charbonnier, Jean-Paul; Smit, Ewoud J.; Viergever, Max A.; Velthuis, Birgitta K.; Vos, Pieter C.

    2013-02-01

    The presence of collateral blood flow is found to be a strong predictor of patient outcome after acute ischemic stroke. Collateral blood flow is defined as an alternative way to provide oxygenated blood to ischemic cerebral tissue. Assessment of collateral blood supply is currently performed by visual inspection of a Computed Tomography Angiogram (CTA) which introduces inter-observer variability and depends on the grading scale. Furthermore, variations in the arterial contrast arrival time may lead to underestimation of collateral blood supply in a CTA which exerts a negative influence on the prediction of patient outcome. In this study, the feasibility of a Computer-aided Diagnosis system is investigated capable of objectively predicting patient outcome. We present a novel automatic method for quantitative assessment of cerebral hypoperfusion in timing-invariant (i.e. delay insensitive) CTA (TI-CTA). The proposed Vessel Density Symmetry algorithm automatically generates descriptive maps based on hemispheric asymmetry of blood vessels. Intensity and symmetry based features are extracted from these descriptive maps and subjected to a best-first-search feature selection. Linear Discriminant Analysis is performed to combine selected features into a likelihood of good patient outcome. Receiver operating characteristic (ROC) analysis is conducted to evaluate the diagnostic performance of the CAD by leave-one- patient-out cross validation. A Positive Predicting Value of 1 was obtained at a sensitivity of 25% with an area under the ROC-curve of 0.86. The results show that the CAD is feasible to objectively predict patient outcome. The presented CAD could make an important contribution to acute ischemic stroke diagnosis and treatment.

  12. 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.

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

    International Nuclear Information System (INIS)

    Xie Jian; Li Minghua; Tan Huaqiao; Zhu Yueqi; Hu Dingjun; Qiao Ruihua; Fan Chunhua

    2009-01-01

    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)

  14. New method of digital angiography

    International Nuclear Information System (INIS)

    Hashiya, Junichi; Korenaga, Takeo; Sakurai, Kenji; Sakai, Fumikazu; Kato, Hisatoyo; Takano, Masao.

    1982-01-01

    New experience of digital angiography using Fuji Intelligent Diagnostic X-ray System was reported. The system utilizes newly developed high sensitivity imaging plate in conjunction with computerized image processor instead of image intensifier-TV series, thus drastically improving image quality. Initial clinical trial was made in 46 cases including intravenous digital subtraction angiography and transcatheter digital arteriography. The advantages of this method were summerized as: 1. better resolution, 2. wider field size, 3. more sophisticated image manipulation program. (author)

  15. 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)

  16. CT angiography in case of occlusion of the basilar artery; Angiographische Diagnostik mittels Mehrzeilen-Spiral-CT beim Akutverschluss der Arteria basilaris

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, R.; Christopoulos, G.; Brunner, H.; Wedell, E. [Inst. fuer Diagnostische und Interventionelle Radiologie, Herz- und Gefaessklinik GmbH, Bad Neustadt an der Saale (Germany); Salveter, E.; Ziegler, V.; Griewing, B. [Neurologische Klinik GmbH, Bad Neustadt an der Saale (Germany)

    2004-07-01

    Objective: to evaluate the diagnostic efficiency of CT angiography in case of clinical signs of acute brainstem infarction for the therapeutic management of catheter-based local thrombolysis. Material and methods: 3 patients (2 males, 1 female) suffering from an acute onset of brainstem symptoms and being suspicious of an occluded basilar artery were included into this report. 1 patient underwent selective vertebral arteriography. 2 patients were initially examined with CT angiography using a 4-row scanner and 100ml intravenous contrast agent. Results: in one patient, an occlusion of the basilar artery was excluded with catheter-based angiography. Sub-sequently, the patient was treated with systemic thrombolysis using r-tPA because of a thalamus infarction seen in MRI. 2 patients who have been initially examined with CT angiography presented with complete occlusions of the basilar arteries. These patients underwent r-tPA thrombolysis by means of superselective micro-catheter approaches of the vertebrobasilar vessels. CT angiography was very useful for determinating the occlusion length of the basilar artery pre-therapeutically, and in 1 case for ruling out an occluded vertrebral artery for catheterization. All patients recovered well under thrombolytic therapy applied systemically or selectively. (orig.)

  17. Magnetic resonance angiography vs. angiography in tetralogy of Fallot.

    Science.gov (United States)

    Rao, Uppalapati Venkateswara; Vanajakshamma, Velam; Rajasekhar, Durgaprasad; Lakshmi, Amancharla Yadagiri; Reddy, Reddivari Niranjan

    2013-08-01

    : To determine whether gadolinium-enhanced three-dimensional magnetic resonance angiography can provide a noninvasive alternative to diagnostic catheterization for evaluation of pulmonary artery anatomy in tetralogy of Fallot. Thirty-five consecutive patients with tetralogy of Fallot, who attended the cardiology outpatient department between January 2008 and December 2009, were included in the study. There were 21 males and 14 females, with a mean age of 9 ± 4.15 years (range, 3-21 years). Thirty-two patients had tetralogy of Fallot with varying severities of valvular and infundibular stenosis. Three patients had tetralogy of Fallot with pulmonary atresia. All patients underwent both cardiac catheterization with X-ray angiography and 3-dimensional magnetic resonance angiography within one month. Measurements of right and left pulmonary arteries and aortopulmonary collaterals were equal by both methods. There was a good correlation between magnetic resonance angiography and catheterization measurements of branch pulmonary arteries. Gadolinium-enhanced three-dimensional magnetic resonance angiography can be used as a reliable noninvasive alternative to X-ray cineangiography for delineation of pulmonary arterial anatomy in sick infants and young children, obviating the need for catheterization.

  18. [Technical principles of OCT angiography].

    Science.gov (United States)

    Fang, P P; Harmening, W M; Müller, P L; Lindner, M; Krohne, T U; Holz, F G

    2016-01-01

    Optical coherence tomography angiography (OCT-A) is a new diagnostic non-invasive method by which the vascular structures of the retina and choroid can be visualized three-dimensionally without need for using fluorescence dyes. The technology of OCT-A is an advancement of the OCT. By means of more powerful software and hardware used for OCT-A not only morphological but also retinal and choroidal vascular perfusion analyses can be performed. In this article, the principles and applications of OCT-A are discussed and compared to other non-invasive diagnostic devices for visualization of the retinal and choroidal blood circulation. This article is based on a selective literature review and analyses of own data. The advantages of OCT-A include easy application without the need for mydriasis or intravenous injection of fluorescence dyes and also the exact three-dimensional localization of vascular changes. In the case of retinal pathologies there is a considerable difference between software-assisted automatic segmentation and the real architecture of the retina, which must be taken into consideration in the clinical interpretation. Of all noninvasive devices for visualization of the retinal and choroidal circulation, OCT-A is the only one which can already be implemented into the clinical routine. With this novel imaging device retinal and choroidal alterations can be visualized in a depth- selective manner and without masking affects, such as pooling or staining phenomena.

  19. Angiography. 2. tot. rev. and enl. ed.; Angiographie

    Energy Technology Data Exchange (ETDEWEB)

    Schild, H. (ed.); Born, M.; Eckert, B.; Hofer, U.; Kaltenborn, H.; Kersjes, W.; Malms, J.; Remig, J.; Schunk, K.; Strunk, H.; Urbach, H.; Wilhelm, K.

    2003-07-01

    New features of the second German edition of this standard textbook: a novel, attractive layout supporting the didactic concept, including highlighted important information and compact summaries. - Comparative evaluation with other methods, such as color Doppler sonography and MR angiography. - Comprehensive revision of images and addition of new pictures. (orig./CB) [German] Neu in der 2. Auflage: neues, ansprechendes Layout fuer noch mehr Didaktik und ''Spass am Lernen'' durch Merksaetze und Zusammenfassungen. - Vergleich mit anderen Verfahren wie Farbdoppler-Sonographie und MR-Angiographie. - Umfassende Ueberarbeitung und Erweiterung des Bildmaterials. (orig./AJ)

  20. Comparison of transradial and transfemoral artery approach for percutaneous coronary angiography and angioplasty: A retrospective seven-year experience from a north Indian center

    Directory of Open Access Journals (Sweden)

    Satyendra Tewari

    2013-07-01

    Conclusion: The number of percutaneous transradial procedures have increased significantly with reduced complication rates and comparable success rate to transfemoral approach, along with the additional benefits to patient in terms of patient comfort, preference and reduced cost of health delivery.

  1. 3D Deep Learning Angiography (3D-DLA) from C-arm Conebeam CT.

    Science.gov (United States)

    Montoya, J C; Li, Y; Strother, C; Chen, G-H

    2018-03-22

    Deep learning is a branch of artificial intelligence that has demonstrated unprecedented performance in many medical imaging applications. Our purpose was to develop a deep learning angiography method to generate 3D cerebral angiograms from a single contrast-enhanced C-arm conebeam CT acquisition in order to reduce image artifacts and radiation dose. A set of 105 3D rotational angiography examinations were randomly selected from an internal data base. All were acquired using a clinical system in conjunction with a standard injection protocol. More than 150 million labeled voxels from 35 subjects were used for training. A deep convolutional neural network was trained to classify each image voxel into 3 tissue types (vasculature, bone, and soft tissue). The trained deep learning angiography model was then applied for tissue classification into a validation cohort of 8 subjects and a final testing cohort of the remaining 62 subjects. The final vasculature tissue class was used to generate the 3D deep learning angiography images. To quantify the generalization error of the trained model, we calculated the accuracy, sensitivity, precision, and Dice similarity coefficients for vasculature classification in relevant anatomy. The 3D deep learning angiography and clinical 3D rotational angiography images were subjected to a qualitative assessment for the presence of intersweep motion artifacts. Vasculature classification accuracy and 95% CI in the testing dataset were 98.7% (98.3%-99.1%). No residual signal from osseous structures was observed for any 3D deep learning angiography testing cases except for small regions in the otic capsule and nasal cavity compared with 37% (23/62) of the 3D rotational angiographies. Deep learning angiography accurately recreated the vascular anatomy of the 3D rotational angiography reconstructions without a mask. Deep learning angiography reduced misregistration artifacts induced by intersweep motion, and it reduced radiation exposure

  2. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

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

  3. Fluorescence angiography in retinal tumours

    International Nuclear Information System (INIS)

    Fuhrmann, M.

    1980-01-01

    On the basis of the available photographic material the results of fluorescein angiography are reported in 4 cases of retinoblastoma and 3 cases of Bourneville's disease. The clinical diagnosis of retinoblastoma was confirmed histologically in all cases since the first eye had been removed for the same reason previously. One child had not yet been treated, and in 3 cases radioactive isotopes were used in the treatment. In the group of phacomatosis the patients had only periodical outpatient examinations. The importance of this angiography in the diagnosis and follow-up of these diseases is stressed. (author)

  4. Simulation of clipping position for cerebral aneurysms using three-dimensional computed tomography angiography

    International Nuclear Information System (INIS)

    Futami, Kazuya; Nakada, Mitsutoshi; Iwato, Masayuki; Kita, Daisuke; Miyamori, Tadao; Yamashita, Junkoh

    2004-01-01

    A novel method for the simulation of the clipping position for cerebral aneurysms based on three-dimensional computed tomography (3D CT) angiography was evaluated. Rotating the regional 3D CT angiography images including the aneurysm provided the virtual intraoperative views of 36 cerebral aneurysms that were eligible for clipping through a pterional approach with a perpendicularly applied straight clip. The cut-along-trace function of the 3D CT workstation was used to simulate the clipping position. The presence or absence of aneurysm remnants was preoperatively evaluated by observing the clipping simulation image. Intraoperative endoscopy and postoperative cerebral angiography were routinely performed to confirm the completeness of obliterations. Nineteen of 21 aneurysms for which complete obliteration was preoperatively expected were confirmed to have no aneurysm remnant. Nine of 15 aneurysms which were expected to have aneurysm remnant were confirmed to persist. The clipping simulation images could correctly predict aneurysm remnant after the initial clipping with a sensitivity of 90.5% and specificity of 60%. The present simulation method can predict aneurysm remnants and improve the likelihood of complete obliteration by clipping. (author)

  5. Direct costs and cost-effectiveness of dual-source computed tomography and invasive coronary angiography in patients with an intermediate pretest likelihood for coronary artery disease.

    Science.gov (United States)

    Dorenkamp, Marc; Bonaventura, Klaus; Sohns, Christian; Becker, Christoph R; Leber, Alexander W

    2012-03-01

    The study aims to determine the direct costs and comparative cost-effectiveness of latest-generation dual-source computed tomography (DSCT) and invasive coronary angiography for diagnosing coronary artery disease (CAD) in patients suspected of having this disease. The study was based on a previously elaborated cohort with an intermediate pretest likelihood for CAD and on complementary clinical data. Cost calculations were based on a detailed analysis of direct costs, and generally accepted accounting principles were applied. Based on Bayes' theorem, a mathematical model was used to compare the cost-effectiveness of both diagnostic approaches. Total costs included direct costs, induced costs and costs of complications. Effectiveness was defined as the ability of a diagnostic test to accurately identify a patient with CAD. Direct costs amounted to €98.60 for DSCT and to €317.75 for invasive coronary angiography. Analysis of model calculations indicated that cost-effectiveness grew hyperbolically with increasing prevalence of CAD. Given the prevalence of CAD in the study cohort (24%), DSCT was found to be more cost-effective than invasive coronary angiography (€970 vs €1354 for one patient correctly diagnosed as having CAD). At a disease prevalence of 49%, DSCT and invasive angiography were equally effective with costs of €633. Above a threshold value of disease prevalence of 55%, proceeding directly to invasive coronary angiography was more cost-effective than DSCT. With proper patient selection and consideration of disease prevalence, DSCT coronary angiography is cost-effective for diagnosing CAD in patients with an intermediate pretest likelihood for it. However, the range of eligible patients may be smaller than previously reported.

  6. MDCT angiography and transcatheter embolization in management ...

    African Journals Online (AJOL)

    Hassan Abdelsalam

    2015-12-18

    Dec 18, 2015 ... 14 patients did not have a MDCT and proceeded straight to angiography;. 6 of them showed active bleeding on angiography. Conclusion: MDCT is an excellent technique before angiography and embolization in cases with acute gastrointestinal bleeding. Transcatheter embolization is an effective tool for ...

  7. The potential for neurovascular intravenous angiography using K-edge digital subtraction angiography

    International Nuclear Information System (INIS)

    Schueltke, E.; Fiedler, S.; Kelly, M.; Griebel, R.; Juurlink, B.; LeDuc, G.; Esteve, F.; Le Bas, J.-F.; Renier, M.; Nemoz, C.; Meguro, K.

    2005-01-01

    Background: Catheterization of small-caliber blood vessels in the central nervous system can be extremely challenging. Alternatively, intravenous (i.v.) administration of contrast agent is minimally invasive and therefore carries a much lower risk for the patient. With conventional X-ray equipment, volumes of contrast agent that could be safely administered to the patient do not allow acquisition of high-quality images after i.v. injection, because the contrast bolus is extremely diluted by passage through the heart. However, synchrotron-based digital K-edge subtraction angiography does allow acquisition of high-quality images after i.v. administration of relatively small doses of contrast agent. Materials and methods: Eight adult male New Zealand rabbits were used for our experiments. Animals were submitted to both angiography with conventional X-ray equipment and synchrotron-based digital subtraction angiography. Results: With conventional X-ray equipment, no contrast was seen in either cerebral or spinal blood vessels after i.v. injection of iodinated contrast agent. However, using K-edge digital subtraction angiography, as little as 1 ml iodinated contrast agent, when administered as i.v. bolus, yielded images of small-caliber blood vessels in the central nervous system (both brain and spinal cord). Conclusions: If it would be possible to image blood vessels of the same diameter in the central nervous system of human patients, the synchrotron-based technique could yield high-quality images at a significantly lower risk for the patient than conventional X-ray imaging. Images could be acquired where catheterization of feeding blood vessels has proven impossible

  8. The potential for neurovascular intravenous angiography using K-edge digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Schueltke, E. [University of Saskatchewan, Saskatoon, SK (Canada) and Walton Medical Centre, University of Liverpool (United Kingdom)]. E-mail: els433@duke.usask.ca; Fiedler, S. [EMBL, Hamburg (Germany); Kelly, M. [University of Saskatchewan, Saskatoon, SK (Canada); Griebel, R. [University of Saskatchewan, Saskatoon, SK (Canada); Juurlink, B. [University of Saskatchewan, Saskatoon, SK (Canada); LeDuc, G. [ESRF, Grenoble (France); Esteve, F. [INSERM U647-ESRF, Grenoble (France); Le Bas, J.-F. [INSERM U647-ESRF, Grenoble (France); Renier, M. [ESRF, Grenoble (France); Nemoz, C. [ESRF, Grenoble (France); Meguro, K. [University of Saskatchewan, Saskatoon, SK (Canada)

    2005-08-11

    Background: Catheterization of small-caliber blood vessels in the central nervous system can be extremely challenging. Alternatively, intravenous (i.v.) administration of contrast agent is minimally invasive and therefore carries a much lower risk for the patient. With conventional X-ray equipment, volumes of contrast agent that could be safely administered to the patient do not allow acquisition of high-quality images after i.v. injection, because the contrast bolus is extremely diluted by passage through the heart. However, synchrotron-based digital K-edge subtraction angiography does allow acquisition of high-quality images after i.v. administration of relatively small doses of contrast agent. Materials and methods: Eight adult male New Zealand rabbits were used for our experiments. Animals were submitted to both angiography with conventional X-ray equipment and synchrotron-based digital subtraction angiography. Results: With conventional X-ray equipment, no contrast was seen in either cerebral or spinal blood vessels after i.v. injection of iodinated contrast agent. However, using K-edge digital subtraction angiography, as little as 1 ml iodinated contrast agent, when administered as i.v. bolus, yielded images of small-caliber blood vessels in the central nervous system (both brain and spinal cord). Conclusions: If it would be possible to image blood vessels of the same diameter in the central nervous system of human patients, the synchrotron-based technique could yield high-quality images at a significantly lower risk for the patient than conventional X-ray imaging. Images could be acquired where catheterization of feeding blood vessels has proven impossible.

  9. Algorithms for the Analysis of 3D Magnetic Resonance Angiography Images

    International Nuclear Information System (INIS)

    Tizon, Xavier

    2004-01-01

    Atherosclerosis is a disease of the arterial wall, progressively impairing blood flow as it spreads throughout the body. The heart attacks and strokes that result of this condition cause more deaths than cancer in industrial countries. Angiography refers to the group of imaging techniques used through the diagnosis, treatment planning and follow-up of atherosclerosis. In recent years, Magnetic Resonance Angiography (MRA) has shown promising abilities to supplant conventional, invasive, X-ray-based angiography. In order to fully benefit from this modality, there is a need for more objective and reproducible methods. This thesis shows, in two applications, how computerized image analysis can help define and implement these methods. First, by using segmentation to improve visualization of blood-pool contrast enhanced (CE)-MRA, with an additional application in coronary Computerized Tomographic Angiography. We show that, using a limited amount of user interaction and an algorithmic framework borrowed from graph theory and fuzzy logic theory, we can simplify the display of complex 3D structures like vessels. Second, by proposing a methodology to analyze the geometry of arteries in whole-body CE-MRA. The vessel centreline is extracted, and geometrical properties of this 3D curve are measured, to improve interpretation of the angiograms. It represents a more global approach than the conventional evaluation of atherosclerosis, as a first step towards screening for vascular diseases. We have developed the methods presented in this thesis with clinical practice in mind. However, they have the potential to be useful to other applications of computerized image analysis

  10. Abdominal wall CT angiography: a detailed account of a newly established preoperative imaging technique.

    Science.gov (United States)

    Phillips, Timothy J; Stella, Damien L; Rozen, Warren M; Ashton, Mark; Taylor, G Ian

    2008-10-01

    Institutional review board approval was obtained for this study, and all patients gave written informed consent. Autologous surgical breast reconstruction with use of abdominal wall donor flaps based on the deep inferior epigastric artery (DIEA) and one or more of its anterior musculocutaneous perforating branches (DIEA perforator flap) is being used with increasing frequency instead of breast reconstruction with use of traditional transverse rectus abdominus musculocutaneous and modified muscle-sparing flaps. Preoperative mapping of the DIEA perforators with abdominal wall computed tomographic (CT) angiography may improve patient care by providing the surgeon with additional information that will lead to optimization of the surgical technique, shorter procedure time, and reduction in the frequency of surgical complications. The branching patterns of the DIEA, the segmental anatomy of the anterior adipocutaneous perforating branches of the DIEA, and the importance of these features in pre- and intraoperative surgical planning necessitate a different approach to abdominal wall CT angiography than that used with other abdominal CT angiographic techniques. In abdominal wall CT angiography, the common femoral artery is used as the bolus trigger, CT scanning is performed in the caudocranial direction, the automatic exposure control feature is disabled, a scaled grid overlay tool is used to present information to the surgeons, and radiation dose is minimized (average dose, 6 mSv). The anatomic accuracy of abdominal wall CT angiography has been investigated in cadaveric and surgical studies, with sensitivity of 96%-100% and specificity of 95%-100%. This detailed description will allow other radiologists and surgeons interested in free DIEP flap surgery to incorporate this useful tool into their practice. (c) RSNA, 2008.

  11. 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...... the teaching segment; the test size was 40% of the teaching segment size. We assessed diagnostic accuracy and readers' confidence. Results were compared using the Wilcoxon rank sum test. RESULTS: Four neurologic consultants and four radiologic residents completed the program. The vascular occlusion teaching...

  12. Teaching writing through genre-based approach

    Directory of Open Access Journals (Sweden)

    Luu, Tuan Trong

    2011-01-01

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

  13. PROJECT BASED ORGANIZATION - AN INTEGRATED APPROACH

    Directory of Open Access Journals (Sweden)

    Claudiu George BOCEAN

    2011-01-01

    Full Text Available As a consequence of globalization, application of new technologies, turbulent economic environment, the uncertainties affecting markets, organizations must cope with ongoing transformational process. In this context, the project-based organization (PBO emerges as an ideal alternative of organizational structure to deal with the emerging features of the temporary and unique demands, within a complex market. This paper brings a new approach trough integration of general management functions with project management activities. The methodology of the proposed ap-proach covers the whole Deming PDCA (Plan, Do, Check, Act cycle, involving quality management in project-based organization's success.

  14. Ecosystem based approaches to climate adaptation

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Jensen, Anne; Termansen, Mette

    This report analyses the prospects and barriers of applying ecosystem based approaches systematically to climate adaptation in urban areas, taking the case of green roofs in Copenhagen Municipality. It looks at planning aspects of green roofs in Copenhagen as well as citizen views and preferences...... regarding green roofs using policy document analysis, interviews with city planners and deliberative valuation methods....

  15. A practice based approach to forest governance

    NARCIS (Netherlands)

    Arts, Bas; Behagel, Jelle|info:eu-repo/dai/nl/35303696X; 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

  16. Feature selection based classifier combination approach for ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Feature selection based classifier combination approach for handwritten Devanagari numeral recognition. Pratibha Singh Ajay Verma ... ensemble of classifiers. The main contribution of the proposed method is that, the method gives quite efficient results utilizing only 10% patterns of the available dataset.

  17. 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...

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

    Science.gov (United States)

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

    2010-01-01

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

  19. 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.

  20. Assessment of anemia during CT pulmonary angiography

    International Nuclear Information System (INIS)

    Jung, Caroline; Groth, Michael; Bley, Thorsten A.; Henes, Frank O.; Treszl, András; Adam, Gerhard; Bannas, Peter

    2012-01-01

    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.

  1. Visual-Functional Mismatch Between Coronary Angiography, Fractional Flow Reserve, and Quantitative Coronary Angiography.

    Science.gov (United States)

    Safi, Morteza; Eslami, Vahid; Namazi, Mohammad Hasan; Vakili, Hossain; Saadat, Habib; Alipourparsa, Saeid; Adibi, Ali; Movahed, Mohammad Reza

    2016-12-01

    Anatomical and functional mismatches are not uncommon in the assessment of coronary lesions. The aim of this study was to identify clinical and lesion-specific factors affecting angiographic, anatomical, and functional mismatch in intermediate coronary lesions. In patients who underwent coronary angiography for clinical reasons, fractional flow reserve (FFR), and quantitative coronary angiography (QCA) analyses for intermediate stenotic lesions were performed simultaneously. Mismatches between the measured values were analyzed. A total of 95 intermediate lesions were assessed simultaneously by visual angiography, FFR, and QCA. The visual-FFR mismatch was found in 40% of the lesions while reverse visual-FFR mismatch was determined in nearly 14% of the lesions. Mismatch and reverse mismatch between FFR and QCA parameters were observed in 10 and 23% of the lesions. FFR value was significant in 32% of the lesions while visually significant stenosis was shown in 61% of the lesions. Among the visual-FFR reverse mismatch group, the prevalence of culprit lesions within the left anterior descending (LAD) was significantly higher than other vessels ( p value mismatches in analyses of intermediate coronary lesions. LAD lesions showed the highest mismatch. Angiographic or QCA estimation of lesion severity has consistently resulted in inappropriate stenting of functionally nonsignificant lesions or undertreatment of significant lesions based on FFR.

  2. Optimization of Ecg Gating in Quantitative Femoral Angiography

    International Nuclear Information System (INIS)

    Nilsson, S.; Berglund, I.; Erikson, U.; Johansson, J.; Walldius, G.

    2003-01-01

    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

  3. 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.

  4. 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.

  5. Advanced Approach of Multiagent Based Buoy Communication.

    Science.gov (United States)

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

    2015-01-01

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

  6. 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...

  7. Is fasting necessary for elective cerebral angiography?

    Science.gov (United States)

    Kwon, O-K; Oh, C W; Park, H; Bang, J S; Bae, H-J; Han, M K; Park, S-H; Han, M H; Kang, H-S; Park, S-K; Whang, G; Kim, B-C; Jin, S-C

    2011-05-01

    In order to prevent unexpected events such as aspiration pneumonia, cerebral angiography has been performed under fasting in most cases. We investigated prospectively the necessity of fasting before elective cerebral angiography. The study is an open-labeled clinical trial without random allocation. In total, 2554 patients who underwent elective cerebral angiography were evaluated on development of nausea, vomiting, and pulmonary aspiration during and after angiography. Potential risks and benefits associated with fasting were provided in written documents and through personal counseling to patients before the procedure. The patients chose their fasting or nonfasting option. No restriction in diet was given after angiography. The patients were observed for 24 hours. Nausea and vomiting during and within 1 hour after angiography was considered as a positive event associated with cerebral angiography. The overall incidence of nausea and vomiting during and within 1 hour after angiography was 1.05% (27/2554 patients). There was no patient with pulmonary aspiration. No statistical difference in nausea and vomiting development between the fasting and the diet groups was found. The incidence of nausea and vomiting associated with cerebral angiography is low and not affected by diet or fasting. Pulmonary aspiration had no difference between the diet and the fasting group. Our study suggests that fasting may not be necessary for patients who undergo elective cerebral angiography.

  8. Angiography of the upper extremity

    International Nuclear Information System (INIS)

    Janevski, B.K.

    1982-01-01

    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.)

  9. Unenhanced 3D turbo spin echo MR angiography of lower extremity arteries: comparison with 128-MDCT angiography.

    Science.gov (United States)

    Demirtaş, Hakan; Parpar, Tuna; Değirmenci, Bumin; Kara, Mustafa; Çelik, Ahmet Orhan; Umul, Ayşe; Kayan, Mustafa; Yılmaz, Ömer

    2016-12-01

    This study aimed to investigate the feasibility and diagnostic power of unenhanced 3D turbo spin echo MR angiography sequence (a technique based on subtraction of corresponding images acquired in diastole and systole, Syngo Native Space-Siemens healthcare) to identify peripheral artery disease (PAD). Thirty patients (619 arterial segments in total) suspected with PAD and who were assessed with lower extremity MDCT angiography were examined starting from the level of aortic bifurcation for both lower extremities by 3D native space MR angiography. Two readers assessed the image quality of native space MR angiography and number of lesions, their degrees of stenosis and localizations. The differences and compliance between the readers in the parameters assessed were investigated. Out of 619 segments; Reader 1 considered 187 segments (30.2 %) and Reader 2 considered 177 segments (28.6 %) to have poor and inadequate MR image quality. When compared to CTA, sensitivity, specificity and diagnostic accuracy of native space MR angiography were calculated as 81.0, 83.1, 82.6 %, respectively, by Reader 1, while the same parameters were calculated as 69.9, 92.6, 84.9 %, respectively, by Reader 2. When the two readers were examined together, sensitivity, specificity, diagnostic accuracy were found to be 76.3, 88.1, 83.7 %, respectively, and the positive predictive value and negative predictive value was 70.3 and 89.9 %, respectively. A significantly better image quality was acquired with the age group below 50 years (p = 0.002). Native space MR angiography technique can be used as the first-step imaging technique before contrast-enhanced examinations in young and middle age patients with suspected PAD and for patients with the risk of nephrogenic systemic fibrosis in chronic renal failure.

  10. Evaluation of angiography performed by radiographers and nurses

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  11. The association between collateral status, recanalization and long term outcome in stroke patients treated with stent retrievers - Are there indications not to perform thrombectomy based on CT angiography?

    Science.gov (United States)

    Nordmeyer, Hannes; Webering, Nadine; Chapot, Rene; Hadisurya, Jeffrie; Heddier, Markus; Stracke, Paul; Berger, Klaus; Isenmann, Stefan; Weber, Ralph

    2017-06-01

    To investigate the association between baseline pial collateral status on computed tomography angiography (CTA) with recanalization and functional outcome in patients with acute anterior circulation stroke treated with stent retriever thrombectomy. Retrospective analysis of 87 patients from a prospective thrombectomy registry. Collateral status on CTA source images was categorized into good, moderate, and poor with the Tan and Miteff scores by two-blinded readers. Association between CTA collateral status and successful recanalization was investigated with univariate regression analysis. Multivariate logistic regression was used to analyse the association between collateral score and favourable clinical outcome (mRS 0-2) and death at follow-up. Mean age was 72.5 years and baseline median NIHSS score was 15. Patients with poor collaterals on Tan score had a significant higher mortality compared with moderate or good collaterals during a mean follow-up period of 5.2 months (85.7% vs. 30.6% vs. 25.7%, Pcollateral score could be assessed only in 65 of the 87 patients and the Tan collateral score had a higher interrater reliability. Poor collaterals on CTA were associated with a very high rate of fatal outcome in anterior circulation stroke patients despite a high rate of successful recanalization with stent retrievers. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-12-15

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

  13. Neural network based multiscale image restoration approach

    Science.gov (United States)

    de Castro, Ana Paula A.; da Silva, José D. S.

    2007-02-01

    This paper describes a neural network based multiscale image restoration approach. Multilayer perceptrons are trained with artificial images of degraded gray level circles, in an attempt to make the neural network learn inherent space relations of the degraded pixels. The present approach simulates the degradation by a low pass Gaussian filter blurring operation and the addition of noise to the pixels at pre-established rates. The training process considers the degraded image as input and the non-degraded image as output for the supervised learning process. The neural network thus performs an inverse operation by recovering a quasi non-degraded image in terms of least squared. The main difference of the approach to existing ones relies on the fact that the space relations are taken from different scales, thus providing relational space data to the neural network. The approach is an attempt to come up with a simple method that leads to an optimum solution to the problem. Considering different window sizes around a pixel simulates the multiscale operation. In the generalization phase the neural network is exposed to indoor, outdoor, and satellite degraded images following the same steps use for the artificial circle image.

  14. Digital subtraction angiography in ischemic cerebrovascular accidents

    International Nuclear Information System (INIS)

    Manelfe, C.; Bonafe, A.; Ducos de Lahitte, M.; Rascol, A.; Prere, J.; Guiraud, B.; Marc-Vergnes, J.P.

    1983-01-01

    Recent advances in computer and radiological technology have permitted reassessment of intravenous angiography in the evaluation of cerebrovascular disorders. Although digital subtraction angiography is a relatively new technique, it has rapidly gained a widespread acceptance. It has extended the use of angiography to outpatients and to people in whom conventional angiography is contraindicated. This reliable, safe, and relatively noninvasive technique offers the user two benefits: real-time subtraction and enhanced image quality. The system allows angiographic evaluation of the extracranial and intracranial vessels by means of intravenous injection of contrast material. Extracranial studies clearly demonstrate stenoses and occlusions of the major cervicocephalic arteries. Intracranial studies usually detect major cerebrovascular occlusions and provide insight into the collateral flow patterns. Intravenous digital subtraction angiography permits accurate assessment of cervicocephalic vessels after surgical repair. Although intravenous digital subtraction angiography obviates the need for conventional angiography in many cases, movements from the patients, or superimposition of vascular structures can substantially degrade the quality of the images. Digital subtraction angiography with intra-arterial injection of contrast medium will be contemplated in patients with poor intravenous digital subtraction angiography studies prior to surgery [fr

  15. Developing Wave Encyclopaedia based on Scientific Approach

    Science.gov (United States)

    Nurafifah, A.; Budi, A. S.; Siahaan, B. Z.

    2017-09-01

    Students have many difficulties in understanding to wave propagation. Such difficulties lead to misconceptions also in understanding sound, light, and electromagnetic wave. Meanwhile, students only use the text book as the learning resources. Whereas students need a more varied and interesting learning resources. This study aims to develop a wave encyclopaedia based on scientific approach as the learning resources that tested the feasibility and superiority. The method used is research by design. The steps are (1) analysing learner characteristic, (2) state objective, (3) select media and materials, (4) utilize materials, (5) requires learner participation, (6) evaluation and revision. The wave encyclopaedia is developed by applying the 5 components of a scientific approach that is, observing, questioning, experimenting, associating, and communicating. In this encyclopaedia also includes fun science activities and exciting recommended websites. The encyclopaedia has been validated by material experts, media experts, and learning experts. And then field trials are conducted to assess an impact on use. Overall the development of encyclopaedia based on scientific approach can enhance learning outcomes of students in high school.

  16. Exercise-based approaches to dysphagia rehabilitation.

    Science.gov (United States)

    Steele, Catriona M

    2012-01-01

    Rehabilitative techniques for dysphagia (swallowing impairment) increasingly employ exercise modeled on methods used to train muscles in sports medicine. Three techniques in particular show promise for improving muscle strength and function related to swallowing: the Shaker exercise, expiratory muscle strength training, and tongue pressure resistance training. All three techniques invoke principles of task specificity, muscular load, resistance, and intensity, and aim to achieve functional changes in swallowing through changes in muscle physiology derived from strength or endurance training. To date, studies of treatment benefit arising from these techniques involve small sample sizes; this is particularly true of randomized studies with controls receiving standard treatment or experiencing spontaneous recovery. Nevertheless, a review of the available literature shows that improvement of penetration-aspiration is a common finding for individuals with dysphagia receiving one of these three treatment approaches. Although hypothesized as an expected outcome of swallow muscle strength training, improvements in post-swallow residues are noted to be uncommon as an outcome of these exercise-based approaches. The available evidence suggests that exercise-based approaches to swallowing rehabilitation do succeed in changing muscle strength and function, but generalization to true swallowing tasks may be somewhat limited. Copyright © 2012 S. Karger AG, Basel.

  17. SLS Navigation Model-Based Design Approach

    Science.gov (United States)

    Oliver, T. Emerson; Anzalone, Evan; Geohagan, Kevin; Bernard, Bill; Park, Thomas

    2018-01-01

    The SLS Program chose to implement a Model-based Design and Model-based Requirements approach for managing component design information and system requirements. This approach differs from previous large-scale design efforts at Marshall Space Flight Center where design documentation alone conveyed information required for vehicle design and analysis and where extensive requirements sets were used to scope and constrain the design. The SLS Navigation Team has been responsible for the Program-controlled Design Math Models (DMMs) which describe and represent the performance of the Inertial Navigation System (INS) and the Rate Gyro Assemblies (RGAs) used by Guidance, Navigation, and Controls (GN&C). The SLS Navigation Team is also responsible for the navigation algorithms. The navigation algorithms are delivered for implementation on the flight hardware as a DMM. For the SLS Block 1-B design, the additional GPS Receiver hardware is managed as a DMM at the vehicle design level. This paper provides a discussion of the processes and methods used to engineer, design, and coordinate engineering trades and performance assessments using SLS practices as applied to the GN&C system, with a particular focus on the Navigation components. These include composing system requirements, requirements verification, model development, model verification and validation, and modeling and analysis approaches. The Model-based Design and Requirements approach does not reduce the effort associated with the design process versus previous processes used at Marshall Space Flight Center. Instead, the approach takes advantage of overlap between the requirements development and management process, and the design and analysis process by efficiently combining the control (i.e. the requirement) and the design mechanisms. The design mechanism is the representation of the component behavior and performance in design and analysis tools. The focus in the early design process shifts from the development and

  18. [High-sensitivity troponin T testing and coronary computed tomography angiography for rapid diagnosis of chest pain in the emergency department].

    Science.gov (United States)

    Durán-Cambra, Albert; Rosselló, Xavier; Sans-Roselló, Jordi; Vila, Montserrat; Hidalgo, Alberto; Rodríguez, Iván Díaz-; Leta, Rubén; Pons-Lladó, Guillem; Ordóñez-Llanos, Jordi; Sionis, Alessandro

    2016-02-01

    To determine the probability of finding significant coronary lesions, the time to diagnosis, and the safety of a new diagnostic approach based on high-sensitivity cardiac troponin T (hsTnT) testing followed by coronary computed tomography angiography (CCTA) in patients with chest pain of possible coronary origin. The method was compared with our hospital emergency department's standard practice. Unblinded randomized controlled trial in a tertiary level university hospital between February 2011 and April 2013. We included emergency patients with chest pain and nondiagnostic electrocardiographic findings. Patients were assigned randomly to the new approach (hsTnT assay, followed by CCTA if the assay findings were negative) or the conventional approach (fourth generation TnT assay and, if negative, followed by an exercise stress test). Invasive coronary angiography was ordered in all patients if the results of either troponin assay, the CCTA, or the stress test were positive. We recorded the results of angiography, time until diagnosis, and all-cause mortality, new myocardial infarction, new unstable angina, or need for revascularization within the next 3 months. Of 102 patients randomized, 7 were excluded; 50 of the remaining 95 patients were assigned to the new strategy, and 45 to the conventional approach. Coronary angiography demonstrated significant lesions in 92.9% of the patients treated with the new strategy and 66.7% of those diagnosed conventionally. A higher percentage of patients were diagnosed within 6 hours with the new approach (20.0% vs 4.4% of conventional-approach patients, P = .023). During the 3 months following diagnosis, 1 death occurred in the intervention group and none in the conventional-approach group. The new strategy could accelerate diagnosis and increase the probability of finding significant coronary lesions, but we found no significant differences in adverse events in the 3 months following diagnosis. These findings should be confirmed

  19. Chronic Total Occlusion Crossing Approach Based on Plaque Cap Morphology: The CTOP Classification.

    Science.gov (United States)

    Saab, Fadi; Jaff, Michael R; Diaz-Sandoval, Larry J; Engen, Gwennan D; McGoff, Theresa N; Adams, George; Al-Dadah, Ashraf; Goodney, Philip P; Khawaja, Farhan; Mustapha, Jihad A

    2018-02-01

    To present the chronic total occlusion (CTO) crossing approach based on plaque cap morphology (CTOP) classification system and assess its ability to predict successful lesion crossing. A retrospective analysis was conducted of imaging and procedure data from 114 consecutive symptomatic patients (mean age 69±11 years; 84 men) with claudication (Rutherford category 3) or critical limb ischemia (Rutherford category 4-6) who underwent endovascular interventions for 142 CTOs. CTO cap morphology was determined from a review pf angiography and duplex ultrasonography and classified into 4 types (I, II, III, or IV) based on the concave or convex shape of the proximal and distal caps. Statistically significant differences among groups were found in patients with rest pain, lesion length, and severe calcification. CTOP type II CTOs were most common and type III lesions the least common. Type I CTOs were most likely to be crossed antegrade and had a lower incidence of severe calcification. Type IV lesions were more likely to be crossed retrograde from a tibiopedal approach. CTOP type IV was least likely to be crossed in an antegrade fashion. Access conversion, or need for an alternate access, was commonly seen in types II, III, and IV lesions. Distinctive predictors of access conversion were CTO types II and III, lesion length, and severe calcification. CTOP type I lesions were easiest to cross in antegrade fashion and type IV the most difficult. Lesion length >10 cm, severe calcification, and CTO types II, III, and IV benefited from the addition of retrograde tibiopedal access.

  20. Contrast-enhanced magnetic resonance angiography

    International Nuclear Information System (INIS)

    Vogl, T.J.; Hoffmann, Y.; Muehler, A.; Felix, R.

    1994-01-01

    Magnetic resonance angiography (MRA) protocols are based on standard sequence protocols like time of flight MRA, which evaluates inflowing spins. This technique is limited by a variety of artifacts like the saturation artifact via turbulent blood flow. Contrast media diminish these artifacts like extracellular agents and blood-pool contrast media. The clinical value of the contrast-enhanced MRA for cerebral pathologies is based on the use of the paramagnetic contrast agent Gd-DTPA. For extracerebral diseases this technique is restricted because of the simultaneous visualization of both arterial and venous vascular territorities. Occult venous sinus thrombosis or AV malformations are clinical essential indications for the use of C-MRA. Experimental data prove the excellent contrast abilities of blood-pool agents like Gd-DTPA-polylysin or Gd-DTPA-albumin, which demonstrate long intravascular persistence and retarded excretion. (orig.) [de

  1. Arteriovenous fistula as a complication of transradial coronary angiography: a case report

    Directory of Open Access Journals (Sweden)

    Dehghani Payam

    2013-01-01

    Full Text Available Abstract Introduction Iatrogenic arteriovenous fistula is a vascular condition that may result from coronary angiography. Many case reports have described arteriovenous fistula occurrence after coronary angiography using the transfemoral access route, but rarely as a complication of using the transradial approach. We report a rare case of a patient with arteriovenous fistula following transradial artery coronary angiography. Case presentation A 62-year-old Caucasian man underwent emergent coronary angiography using the right radial artery approach. One month after angiography, he discovered a turbulent sound near the access site. A right radial arteriovenous fistula was found upon duplex ultrasound investigation. The patient was treated conservatively. At 1-year follow-up, the arteriovenous fistula was unchanged and the patient remained hemodynamically stable and asymptomatic. Conclusion Iatrogenic arteriovenous fistula is a rare vascular complication of transradial artery coronary angiography. The natural history of arteriovenous fistula is benign and is thought to resolve spontaneously; therefore, a conservative approach, as opposed to surgical ligation, is recommended as the first-line treatment.

  2. Arteriovenous fistula as a complication of transradial coronary angiography: a case report.

    Science.gov (United States)

    Dehghani, Payam; Culig, Jennifer; Patel, Darshan; Kraushaar, Greg; Schulte, Paul

    2013-01-14

    Iatrogenic arteriovenous fistula is a vascular condition that may result from coronary angiography. Many case reports have described arteriovenous fistula occurrence after coronary angiography using the transfemoral access route, but rarely as a complication of using the transradial approach. We report a rare case of a patient with arteriovenous fistula following transradial artery coronary angiography. A 62-year-old Caucasian man underwent emergent coronary angiography using the right radial artery approach. One month after angiography, he discovered a turbulent sound near the access site. A right radial arteriovenous fistula was found upon duplex ultrasound investigation. The patient was treated conservatively. At 1-year follow-up, the arteriovenous fistula was unchanged and the patient remained hemodynamically stable and asymptomatic. Iatrogenic arteriovenous fistula is a rare vascular complication of transradial artery coronary angiography. The natural history of arteriovenous fistula is benign and is thought to resolve spontaneously; therefore, a conservative approach, as opposed to surgical ligation, is recommended as the first-line treatment.

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

    International Nuclear Information System (INIS)

    Park, Sung Ho; Suh, Sang Hyun; Kim, Jin Na; Kim, Eung Yeop; Kim, Dong Joon; Lee, Seung Koo; Kim, Dong Ik

    2007-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-08-15

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

  5. 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...

  6. Market-based approaches to tree valuation

    Science.gov (United States)

    Geoffrey H. Donovan; David T. Butry

    2008-01-01

    A recent four-part series in Arborist News outlined different appraisal processes used to value urban trees. The final article in the series described the three generally accepted approaches to tree valuation: the sales comparison approach, the cost approach, and the income capitalization approach. The author, D. Logan Nelson, noted that the sales comparison approach...

  7. Hemifacial spasm. Study by magnetic resonance angiography

    International Nuclear Information System (INIS)

    Bittar, Miriam Salvadori; Staut, Claudio Cesar Vilela; Barbosa, Egberto Reis; Bacheschi, Luiz Alberto; Magalhaes, Alvaro Cebrian de Almeida

    1995-01-01

    Nine patients with idiopathic hemifacial spasm were evaluated with cranial magnetic resonance imaging and angiography. Alterations of the posterior fossa vasculature, possibly related to the facial nerve irritation, were found in 8 patients (88%). Magnetic resonance angiography is a noninvasive procedure and appears to be a sensitive method to evaluate hemifacial spasm etiology. (author)

  8. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

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

  9. Risk-based remediation: Approach and application

    International Nuclear Information System (INIS)

    Frishmuth, R.A.; Benson, L.A.

    1995-01-01

    The principle objective of remedial actions is to protect human health and the environment. Risk assessments are the only defensible tools available to demonstrate to the regulatory community and public that this objective can be achieved. Understanding the actual risks posed by site-related contamination is crucial to designing cost-effective remedial strategies. All to often remedial actions are overdesigned, resulting in little to no increase in risk reduction while increasing project cost. Risk-based remedial actions have recently been embraced by federal and state regulators, industry, government, the scientific community, and the public as a mechanism to implement rapid and cost-effective remedial actions. Emphasizing risk reduction, rather than adherence to ambiguous and generic standards, ensures that only remedial actions required to protect human health and the environment at a particular site are implemented. Two sites are presented as case studies on how risk-based approaches are being used to remediate two petroleum hydrocarbon contaminated sites. The sites are located at two US Air Force Bases, Wurtsmith Air Force Base (AFB) in Oscoda, Michigan and Malmstrom AFB in Great Falls, Montana

  10. Exercise intravenous digital subtraction angiography

    International Nuclear Information System (INIS)

    Yiannikas, J.

    1986-01-01

    Attempts to use exercise ventriculography have been made, not only to give diagnostic and perhaps even prognostic information in patients with coronary artery disease, but also in patients with valvular heart disease both before and after surgical intervention. Clearly an accurate method of assessing ventricular function under conditions of stress in various cardiac diseases would provide important information that would help in patient management. Exercise ventriculography using gated blood pool equilibrium technetium studies are widely used, but are limited by spatial resolution and by the foreshortening affects of visualizing the left ventricular chamber in the left anterior oblique view. First pass radionuclide studies have the added advantage of being able to visualize the ventricular chamber in the anterior or even the right anterior oblique view, but are even more limited by their spatial resolution problems. Several investigations have shown that digital subtraction angiography produces left ventricular images with a spatial resolution almost identical to that of conventional contrast ventriculography, but without the inherent problems of cardiac arrhythmias, which often limit the assessment of left ventricular function. Because of its ability to accurately delineate wall motion abnormalities, the technique may provide an adequate assessment of global and regional left ventricular function after exercise. Digital subtraction angiography may identify ischemic wall motion abnormalities produced by exercise in patients who already had significant permanent left ventricular damage from myocardial infarction

  11. Image quality of ct angiography using model-based iterative reconstruction in infants with congenital heart disease: Comparison with filtered back projection and hybrid iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Qianjun, E-mail: jiaqianjun@126.com [Southern Medical University, Guangzhou, Guangdong (China); Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong (China); Department of Catheterization Lab, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong (China); Zhuang, Jian, E-mail: zhuangjian5413@tom.com [Department of Cardiac Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong (China); Jiang, Jun, E-mail: 81711587@qq.com [Department of Radiology, Shenzhen Second People’s Hospital, Shenzhen, Guangdong (China); Li, Jiahua, E-mail: 970872804@qq.com [Department of Catheterization Lab, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong (China); Huang, Meiping, E-mail: huangmeiping_vip@163.com [Department of Catheterization Lab, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong (China); Southern Medical University, Guangzhou, Guangdong (China); Liang, Changhong, E-mail: cjr.lchh@vip.163.com [Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong (China); Southern Medical University, Guangzhou, Guangdong (China)

    2017-01-15

    Purpose: To compare the image quality, rate of coronary artery visualization and diagnostic accuracy of 256-slice multi-detector computed tomography angiography (CTA) with prospective electrocardiographic (ECG) triggering at a tube voltage of 80 kVp between 3 reconstruction algorithms (filtered back projection (FBP), hybrid iterative reconstruction (iDose{sup 4}) and iterative model reconstruction (IMR)) in infants with congenital heart disease (CHD). Methods: Fifty-one infants with CHD who underwent cardiac CTA in our institution between December 2014 and March 2015 were included. The effective radiation doses were calculated. Imaging data were reconstructed using the FBP, iDose{sup 4} and IMR algorithms. Parameters of objective image quality (noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR)); subjective image quality (overall image quality, image noise and margin sharpness); coronary artery visibility; and diagnostic accuracy for the three algorithms were measured and compared. Results: The mean effective radiation dose was 0.61 ± 0.32 mSv. Compared to FBP and iDose{sup 4}, IMR yielded significantly lower noise (P < 0.01), higher SNR and CNR values (P < 0.01), and a greater subjective image quality score (P < 0.01). The total number of coronary segments visualized was significantly higher for both iDose{sup 4} and IMR than for FBP (P = 0.002 and P = 0.025, respectively), but there was no significant difference in this parameter between iDose{sup 4} and IMR (P = 0.397). There was no significant difference in the diagnostic accuracy between the FBP, iDose{sup 4} and IMR algorithms (χ{sup 2} = 0.343, P = 0.842). Conclusions: For infants with CHD undergoing cardiac CTA, the IMR reconstruction algorithm provided significantly increased objective and subjective image quality compared with the FBP and iDose{sup 4} algorithms. However, IMR did not improve the diagnostic accuracy or coronary artery visualization compared with iDose{sup 4}.

  12. 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

  13. 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

  14. 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.

  15. Hydrogel based approaches for cardiac tissue engineering.

    Science.gov (United States)

    Saludas, Laura; Pascual-Gil, Simon; Prósper, Felipe; Garbayo, Elisa; Blanco-Prieto, María

    2017-05-25

    Heart failure still represents the leading cause of death worldwide. Novel strategies using stem cells and growth factors have been investigated for effective cardiac tissue regeneration and heart function recovery. However, some major challenges limit their translation to the clinic. Recently, biomaterials have emerged as a promising approach to improve delivery and viability of therapeutic cells and proteins for the regeneration of the damaged heart. In particular, hydrogels are considered one of the most promising vehicles. They can be administered through minimally invasive techniques while maintaining all the desirable characteristics of drug delivery systems. This review discusses recent advances made in the field of hydrogels for cardiac tissue regeneration in detail, focusing on the type of hydrogel (conventional, injectable, smart or nano- and micro-gel), the biomaterials used for its manufacture (natural, synthetic or hybrid) and the therapeutic agent encapsulated (stem cells or proteins). We expect that these novel hydrogel-based approaches will open up new possibilities in drug delivery and cell therapies. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. 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.

  17. 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.

  18. CAPILLARY NETWORK ANOMALIES IN BRANCH RETINAL VEIN OCCLUSION ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

    Science.gov (United States)

    Rispoli, Marco; Savastano, Maria Cristina; Lumbroso, Bruno

    2015-11-01

    To analyze the foveal microvasculature features in eyes with branch retinal vein occlusion (BRVO) using optical coherence tomography angiography based on split spectrum amplitude decorrelation angiography technology. A total of 10 BRVO eyes (mean age 64.2 ± 8.02 range between 52 years and 76 years) were evaluated by optical coherence tomography angiography (XR-Avanti; Optovue). The macular angiography scan protocol covered a 3 mm × 3 mm area. The focus of angiography analysis were two retinal layers: superficial vascular network and deep vascular network. The following vascular morphological congestion parameters were assessed in the vein occlusion area in both the superficial and deep networks: foveal avascular zone enlargement, capillary non-perfusion occurrence, microvascular abnormalities appearance, and vascular congestion signs. Image analyses were performed by 2 masked observers and interobserver agreement of image analyses was 0.90 (κ = 0.225, P network of BRVO, a decrease in capillary density with foveal avascular zone enlargement, capillary non-perfusion occurrence, and microvascular abnormalities appearance was observed (P network showed the main vascular congestion at the boundary between healthy and nonperfused retina. Optical coherence tomography angiography in BRVO allows to detect foveal avascular zone enlargement, capillary nonperfusion, microvascular abnormalities, and vascular congestion signs both in the superficial and deep capillary network in all eyes. Optical coherence tomography angiography technology is a potential clinical tool for BRVO diagnosis and follow-up, providing stratigraphic vascular details that have not been previously observed by standard fluorescein angiography. The normal retinal vascular nets and areas of nonperfusion and congestion can be identified at various retinal levels. Optical coherence tomography angiography provides noninvasive images of the retinal capillaries and vascular networks.

  19. 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

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

    International Nuclear Information System (INIS)

    Zuelich, K.J.

    1988-01-01

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

  1. 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.

  2. Preprocedure and Postprocedure Predictive Values of Serum β2-Microglobulin for Contrast-Induced Nephropathy in Patients Undergoing Coronary Computed Tomography Angiography: A Comparison With Creatinine-Based Parameters and Cystatin C.

    Science.gov (United States)

    Li, Suhua; Zheng, Zhenda; Tang, Xixiang; Peng, Long; Luo, Yanting; Dong, Ruimin; Zhao, Yunyue; Liu, Jinlai

    2015-01-01

    This study aimed to investigate the values of serum β2-microglobulin to predict contrast-induced nephropathy (CIN) before and early after coronary computed tomography angiography (CCTA), comparing with creatinine-based parameters and cystatin C. A total of 424 patients were enrolled. Serum β2-microglobulin, cystatin C, and creatinine were measured at 0, 24, and 48 hours of CCTA. Contrast-induced nephropathy was defined as an elevation of serum creatinine level by 25% or higher or 0.5 mg/dL or greater from baseline within 48 hours. The estimated glomerular filtration rate (eGFR) was calculated by the Modification of Diet in Renal Disease study equation. Receiver operating characteristic curves and multivariate logistic regression analysis were used to detect the efficiency of biomarkers in predicting CIN. Fifty-two subjects (12.26%) developed CIN. Before CCTA, CIN was predicted by both baseline β2-microglobulin (area under the receiver operating characteristic curve [AUC], 0.791; P creatinine and eGFR were not predictive. After CCTA, CIN was predicted by both the absolute post-CCTA levels of β2-microglobulin, cystatin C, creatinine, and eGFR (AUC, 0.842 vs 0.961 vs 0.691 vs 0.688 at 24 hours, P Serum β2-microglobulin, with values superior to creatinine-based parameters and similar with cystatin C, was a useful biomarker for the prediction of CIN at pre-CCTA and early post-CCTA.

  3. Comparison of a safety strategy using transradial access and dual-axis rotational coronary angiography with transfemoral access and standard coronary angiography.

    Science.gov (United States)

    Yasar, Ayse S; Perino, Alexander C; Dattilo, Philip B; Casserly, Ivan P; Carroll, John D; Messenger, John C

    2013-10-01

    We sought to investigate the radiation exposure and contrast utilization associated with using a strategy of transradial access and rotational angiography (radial-DARCA) compared to the traditional approach of transfemoral access and standard angiography (femoral-SA). There is an increased focus on optimizing patient safety during cardiac catheterization procedures. Professional guidelines have highlighted physician responsibility to minimize radiation doses and contrast volume. Dual axis rotational coronary angiography (DARCA) is the most recently investigated type of rotational angiography. This new technique permits complete visualization of the left or right coronary tree with a single injection, and is felt to reduce contrast and radiation exposure. A total of 56 consecutive patients who underwent radial-DARCA were identified. From the same time period, an age- and gender-matched group of 61 patients who had femoral-SA were selected for comparison. Total volume of contrast agent used, fluoroscopy time, and 2 measures of radiation dose (dose area product and air kerma) were recorded for each group. Mean contrast agent use and patient radiation exposure of the radial-DARCA group were significantly less than that of the femoral-SA group. There was no significant difference in fluoroscopy time between the 2 groups. Physicians can successfully employ an innovative safety strategy of transradial access combined with DARCA that is feasible and is associated with lower radiation doses and contrast volume than femoral artery access and traditional coronary angiography approach. © 2013, Wiley Periodicals, Inc.

  4. CT angiography and magnetic resonance angiography findings after surgical and interventional radiology treatment of peripheral arterial obstructive disease.

    Science.gov (United States)

    Anzidei, Michele; Lucatelli, Pierleone; Napoli, Alessandro; Jens, Sjoerd; Saba, Luca; Cartocci, Gaia; Sedati, Pietro; d'Adamo, Alessandro; Catalano, Carlo

    2015-01-01

    In the last years, technical innovations in the field of CT angiography (CTA) and magnetic resonance angiography (MRA) have allowed accurate and highly detailed evaluation of peripheral vascular pathologies. This has dramatically changed the diagnostic approach in treatment planning of peripheral arterial obstructive disease and also enabling early identification of treatment failure or treatment-related complications after surgical or endovascular procedures. Although Doppler Ultrasound is the first-line imaging modality during follow-up after treatment, its role is currently diminishing in importance mostly because of the proliferation of high-end CT and MR scanners capable of fast, reproducible, and highly reliable vascular imaging. The aim of this study is to review the various surgical and endovascular procedures for peripheral arterial obstructive disease and to provide CTA and MRA samples of common and uncommon complications related to treatment. Copyright © 2015 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  5. The Significance of Temperature Based Approach Over the Energy Based Approaches in the Buildings Thermal Assessment

    Science.gov (United States)

    Albatayneh, Aiman; Alterman, Dariusz; Page, Adrian; Moghtaderi, Behdad

    2017-05-01

    The design of low energy buildings requires accurate thermal simulation software to assess the heating and cooling loads. Such designs should sustain thermal comfort for occupants and promote less energy usage over the life time of any building. One of the house energy rating used in Australia is AccuRate, star rating tool to assess and compare the thermal performance of various buildings where the heating and cooling loads are calculated based on fixed operational temperatures between 20 °C to 25 °C to sustain thermal comfort for the occupants. However, these fixed settings for the time and temperatures considerably increase the heating and cooling loads. On the other hand the adaptive thermal model applies a broader range of weather conditions, interacts with the occupants and promotes low energy solutions to maintain thermal comfort. This can be achieved by natural ventilation (opening window/doors), suitable clothes, shading and low energy heating/cooling solutions for the occupied spaces (rooms). These activities will save significant amount of operating energy what can to be taken into account to predict energy consumption for a building. Most of the buildings thermal assessment tools depend on energy-based approaches to predict the thermal performance of any building e.g. AccuRate in Australia. This approach encourages the use of energy to maintain thermal comfort. This paper describes the advantages of a temperature-based approach to assess the building's thermal performance (using an adaptive thermal comfort model) over energy based approach (AccuRate Software used in Australia). The temperature-based approach was validated and compared with the energy-based approach using four full scale housing test modules located in Newcastle, Australia (Cavity Brick (CB), Insulated Cavity Brick (InsCB), Insulated Brick Veneer (InsBV) and Insulated Reverse Brick Veneer (InsRBV)) subjected to a range of seasonal conditions in a moderate climate. The time required for

  6. Digital subtraction angiography of the heart and lungs

    International Nuclear Information System (INIS)

    Moodie, D.S.; Yiannikas, J.

    1986-01-01

    This book contains 12 chapters. Some of the chapter titles are: Physical Principles of Cardiac Digital Subtraction Angiography, The Use of Intravenous Digital Subtraction Angiography in Evaluating Patients with Complex Congenital Heart Disease, Exercise Intravenous Digital Subtraction Angiograpny, Cardiomyopathic and Cardiac Neoplastic Disease, Digital Subtraction Angiography in the Catheterization Laboratory, and Cardiac Digital Subtraction Angiography - Future Directions

  7. Photodynamic therapy monitoring with optical coherence angiography

    Science.gov (United States)

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

    2017-02-01

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

  8. Renal angiography with iohexol and metrizoate

    Energy Technology Data Exchange (ETDEWEB)

    Toernquist, C.; Holtaes, S.

    1984-02-01

    The nephrotoxicity of the ionic contrast medium metrizoate was compared with that of nonionic iohexol when used for renal angiography. Fifteen patients who underwent renal angiography with metrizoate and 15 with iohexol were studied. Serum creatinine level, Cr-51-EDTA clearance, and urine albumin level were recorded before and after angiography. Metrizoate affected renal function, as indicated both by a transient decrease in glomerular filtration rate and by a transient albuminuria. Renal function was unaffected by iohexol. Furthermore, iohexol produced less subjective discomfort than metrizoate. There appeared to be no difference in the quality of the angiograms obtained with the two media.

  9. 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.)

  10. Quality based approach for adaptive face recognition

    Science.gov (United States)

    Abboud, Ali J.; Sellahewa, Harin; Jassim, Sabah A.

    2009-05-01

    Recent advances in biometric technology have pushed towards more robust and reliable systems. We aim to build systems that have low recognition errors and are less affected by variation in recording conditions. Recognition errors are often attributed to the usage of low quality biometric samples. Hence, there is a need to develop new intelligent techniques and strategies to automatically measure/quantify the quality of biometric image samples and if necessary restore image quality according to the need of the intended application. In this paper, we present no-reference image quality measures in the spatial domain that have impact on face recognition. The first is called symmetrical adaptive local quality index (SALQI) and the second is called middle halve (MH). Also, an adaptive strategy has been developed to select the best way to restore the image quality, called symmetrical adaptive histogram equalization (SAHE). The main benefits of using quality measures for adaptive strategy are: (1) avoidance of excessive unnecessary enhancement procedures that may cause undesired artifacts, and (2) reduced computational complexity which is essential for real time applications. We test the success of the proposed measures and adaptive approach for a wavelet-based face recognition system that uses the nearest neighborhood classifier. We shall demonstrate noticeable improvements in the performance of adaptive face recognition system over the corresponding non-adaptive scheme.

  11. 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 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.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.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.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.

  12. Comparison of spiral CT angiography vs digital subtraction angiography in the evaluation of living kidney donors

    Directory of Open Access Journals (Sweden)

    Santosh Kumar

    2002-01-01

    Full Text Available Recent reports suggest that spiral computed tomographic (CT angiography could replace conventional angiogra-phy and intravenous urography (IVU for the assessment of potential live kidney donors. The purpose of this study was to assess the accuracy of spiral CT in kidney donor workup. 10 consecutive renal donors had IVU, percutane-ous transfemoral selective renal angiography and spiral CT angiography between January and March 2001. The spiral CT and renal angiograms were assessed independ-ently by two radiologists. The number of renal arteries, pres-ence or absence of renal artery stenoses and associated parenchymal abnormalities were assessed. A total of 27 renal arteries were detected. Transverse scans viewed in a tine loop format with maximum intensity projection and shaded surface display detected all 27 vessels. All 27 ves-sels were detected by conventional catheter angiography. A simple renal cyst was noted in both spiral CT and con-ventional angiogram. Venous anatomy including a retroaortic renal vein was visualized in spiral CT angiogram but not visualized by conventional angiography. Spiral CT angiography performed as an outpatient procedure is less invasive, less expensive, and provides good images of the arterial and venous anatomy in addition to the visualiza-tion of the other abdominal viscera. A plain X-ray of the abdomen was taken 15 rains after injection of contrast to acquire an IVU like image. Spiral CT angiography has the potential to replace conventional catheter angiography and IVU in the assessment of renal donors.

  13. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Radiology and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ... pictures of the major blood vessels throughout your body. It may be performed with or without contrast ...

  14. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Abdominal Ultrasound Video: Pelvic Ultrasound Medical Imaging Costs Radiology and You Take our survey Sponsored by Image/ ... Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot org Hello, I’m Dr. Elliot ...

  15. Application of OCT angiography in ophthalmology

    Directory of Open Access Journals (Sweden)

    Ai-Ping Yang

    2017-11-01

    Full Text Available Optical coherence tomography angiography(OCTAis a new technology of angiography in recent years. In addition to the advantages of traditional OCT, it can observe blood flow in different retinal and choroidal segmentation slab. By using the pseudo-color, abnormal vascular structure can be distinguished from normal vascular structure of the retina. Dye injection is not needed with OCTA, which is different from fundus fluorescein angiography(FFAand indocyanine green angiography(ICGA. OCTA provides more and more accurate blood flow information. However, like other biometric technology, OCTA has its limitations and shortcomings. This review will analyze and summarize the operating principle of OCTA, its application in ophthalmology, as well as its advantages and limitations.

  16. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) ... Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You ...

  17. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... mild sedative prior to the examination. For more information about Magnetic Resonance Angiography of MRA or any ... Inc. (RSNA). To help ensure current and accurate information, we do not permit copying but encourage linking ...

  18. Magnetic Resonance Angiography in the Pig using Hyperpolarized Water

    DEFF Research Database (Denmark)

    Lipsø, Hans Kasper Wigh; Bowen, Sean; Laustsen, Christoffer

    , the magnetization achievable with hyperpolarized water is superior to other nuclei. Methods A 1 mL sample of 50% water and 50% glycerol with 30 mM TEMPO is polarized in a Spinlab (GE Healthcare) at 5 T, 0.9 K, 139.9 GHz for an hour. The sample is rapidly dissolved in 16 mL deoxygenized dissolution medium (DM......Introduction Magnetic Resonance Angiography (MRA) is an important tool in diagnostics of medical conditions such as emboli, stenosis and aneurysms. Sub-millimetre resolution can be obtained with proton imaging, and further optimization can be obtained with Gd-based blood pool agents1. However......, the acquisition time is several minutes, and conventional MRA methods thus fail to image within a single respiration or heartbeat and therefore suffers from motion artefacts. We demonstrate that hyperpolarized (HP) water can be used as an imaging agent to provide subsecond angiographies in pigs. Previous work...

  19. 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.

  20. MR angiography in pediatric neurological disorders

    International Nuclear Information System (INIS)

    Lee, B.C.P.; Park, T.S.; Kaufman, B.A.

    1995-01-01

    MR angiography using 3D and 2D time-of-flight techniques were used to evaluate pediatric neurological disorders. MRA (arteriography) and MRV (venography) were abnormal in 63 and 45 cases, respectively. Conventional cerebral angiography was performed in 30 cases. These techniques were compared with MRI and conventional angiography. In addition, the value of MR angiography for surgical planning was subjectively evaluated. Our results showed that intracranial vessels were invariably better shown on MR angiography than on MRI. MRA and MRV were most useful in evaluating vascular distortions related to congenital brain malformations and intracranial tumors. MRA was valuable in detecting arterial narrowing but overestimated the degree of stenosis compared with conventional angiography. MRV was the technique of choice for evaluation of dural sinus and cerebral venous thrombosis and compression. MRA played little to no role in preoperative planning of vascular malformations and aneurysms. It did not appear to be accurate in assessing tumor vascularity or lesions in small arteries and arteritis. (orig.)

  1. A Mistake Based Approach Probing Students' Under- standing of PV ...

    Indian Academy of Sciences (India)

    lic forum results in a paradigm of learning called the 'mis- take based approach'. This approach is a subset ... necting the science with the math – there are so many equations floating around, but which one to use for which ..... In conjunction with the traditional approach of teaching subject- wise/chapter-wise, this approach ...

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

    NARCIS (Netherlands)

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

    2010-01-01

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

  3. The Role of Coronary Computed Tomography Angiography and Cardiac Magnetic Resonance in STEMI Patients with Normal Coronary Angiography

    Directory of Open Access Journals (Sweden)

    Beganu Elena

    2017-09-01

    Full Text Available Usually, the diagnosis of myocardial infarction based on patient symptoms, electrocardiogram (ECG changes, and cardiac enzymes, is not a challenge for cardiologists. The correlation between coronary anatomy and the ECG territories that present ischemic changes can help the clinician to estimate which coronary artery presents lesions upon performing a coronary angiogram. In certain situations, the diagnosis of myocardial infarction can be difficult due to the lack of correlations between the clinical and paraclinical examinations and the coronary angiogram. In some cases, patients with chest pain and ST-segment elevation on the ECG tracing present with a normal coronary angiography. In other cases, patients without important changes on the ECG can present critical lesions or even occlusions upon angiographic examination. The aim of this article is to highlight the role of noninvasive coronary magnetic resonance and multi-slice computed tomography in patients with ST-segment elevation myocardial infarction and normal coronary angiography.

  4. Filtered region of interest cone-beam rotational angiography

    International Nuclear Information System (INIS)

    Schafer, Sebastian; Noeel, Peter B.; Walczak, Alan M.; Hoffmann, Kenneth R.

    2010-01-01

    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

  5. Nanotechnology based approaches in cancer therapeutics

    Science.gov (United States)

    Kumer Biswas, Amit; Reazul Islam, Md; Sadek Choudhury, Zahid; Mostafa, Asif; Fahim Kadir, Mohammad

    2014-12-01

    The current decades are marked not by the development of new molecules for the cure of various diseases but rather the development of new delivery methods for optimum treatment outcome. Nanomedicine is perhaps playing the biggest role in this concern. Nanomedicine offers numerous advantages over conventional drug delivery approaches and is particularly the hot topic in anticancer research. Nanoparticles (NPs) have many unique criteria that enable them to be incorporated in anticancer therapy. This topical review aims to look at the properties and various forms of NPs and their use in anticancer treatment, recent development of the process of identifying new delivery approaches as well as progress in clinical trials with these newer approaches. Although the outcome of cancer therapy can be increased using nanomedicine there are still many disadvantages of using this approach. We aim to discuss all these issues in this review.

  6. Nanotechnology based approaches in cancer therapeutics

    International Nuclear Information System (INIS)

    Biswas, Amit Kumer; Islam, Md Reazul; Choudhury, Zahid Sadek; Kadir, Mohammad Fahim; Mostafa, Asif

    2014-01-01

    The current decades are marked not by the development of new molecules for the cure of various diseases but rather the development of new delivery methods for optimum treatment outcome. Nanomedicine is perhaps playing the biggest role in this concern. Nanomedicine offers numerous advantages over conventional drug delivery approaches and is particularly the hot topic in anticancer research. Nanoparticles (NPs) have many unique criteria that enable them to be incorporated in anticancer therapy. This topical review aims to look at the properties and various forms of NPs and their use in anticancer treatment, recent development of the process of identifying new delivery approaches as well as progress in clinical trials with these newer approaches. Although the outcome of cancer therapy can be increased using nanomedicine there are still many disadvantages of using this approach. We aim to discuss all these issues in this review. (review)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-11-15

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

  8. Comparison of effective Hough transform-based fingerprint alignment approaches

    CSIR Research Space (South Africa)

    Mlambo, CS

    2014-08-01

    Full Text Available In this paper, two effective and mostly used Hough Transform (HT) based fingerprint alignment approaches are compared, namely; Local Match Based Alignment (LMBA) and Discretized Rotation Based Alignment (DRBA). The comparison was performed...

  9. MR angiography of the abdomen

    International Nuclear Information System (INIS)

    Johnson, C.D.; Ehman, R.L.

    1989-01-01

    Recent developments in MR imaging have included projection images of vascular anatomy. One approach for obtaining these images was based on computer raytracing through a volume set of tomographic source sections in which vascular structures had high signal intensity. The authors investigated whether the final projecting images provided diagnostic information that could not be appreciated in the original (source) tomographic sections. Angiographic images were obtained in 15 patients with chronic liver disease by using a time-of-flight technique based on breathhold gradient-recalled image volume data sets. Films were analyzed by studying projection angiograms alone, tomographic images alone, and both projection and tomographic images. Projection angiographic images alone provided little diagnostic information that could not be appreciated readily in the simple tomographic data sets. Many important diagnostic observations that were apparent in the tomographic images could not be appreciated in the projection MR angiograms

  10. Digital angiography of camel foot

    International Nuclear Information System (INIS)

    Dehghani, S.N.; Kohkiloyehzadeh, M.; Sazmand, A.

    2011-01-01

    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

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

    NARCIS (Netherlands)

    C.J.J. Van Asch (Charlotte J.J.); B.K. Velthuis (Birgitta K.); G.J.E. Rinkel (Gabriël J.E.); A. Algra (Ale); G.A.P. de Kort (G. A P); T.D. Witkamp (Theo); J.C.M. De Ridder (Johanna C.M.); K.M. Van Nieuwenhuizen (Koen M.); F.-E. De Leeuw (Frank-Erik); W.J. Schonewille (Wouter); P.L.M. de Kort (Paul); D.W.J. Dippel (Diederik); T.W.M. Raaymakers (Theodora W.M.); J. Hofmeijer; M.J.H. Wermer (Marieke); H. Kerkhoff (Henk); K. Jellema (Korné); I.M. Bronner (Irene M.); M.J.M. Remmers (Michel ); H.P. Bienfait (Henri); R.J.G.M. Witjes (Ron J.G.M.); J.P. Greving (Jacoba); C.J.M. Klijn (Catharina J.M.); H.F. de Leeuw (Frank); H.B. Boogaarts; E.J. van Dijk (Ewoud); W.J. Schonewille; W.M.J. Pellikaan; C. Puppels-De Waard; P.L.M. De Kort; J.P. Peluso; J. van Tuijl (Jordie); J. Hofmeijer; F.B.M. Joosten (Frank); D.W.J. Dippel (Diederik); L. Khajeh (Ladbon); T.W.M. Raaijmakers; M.J. Wermer; M.A.A. van Walderveen (Marianne); H. Kerkhoff; E. Zock; K. Jellema (Korné); G.J. Lycklama à Nijeholt (Geert); I.M. Bronner; M.J.M. Remmers; R.J.G.M. Witjes; H.P. Bienfait; K.E. Droogh-Greve; R. Donders (Rogier); V.I.H. Kwa; T.H.C.M.L. Schreuder (Tobien H. C. M. L.); C.L. Franke (Cees); J.S. Straver; C. Jansen; S.L.M. Bakker (Stef); C.C. Pleiter (C.); M.C. Visser; C.J.J. Van Asch; B.K. Velthuis (Birgitta); G.J.E. Rinkel (Gabriel); K.M. Van Nieuwenhuizen; C.J.M. Klijn (Catharina J.M.)

    2015-01-01

    textabstractStudy question What are the diagnostic yield and accuracy of early computed tomography (CT) angiography followed by magnetic resonance imaging/angiography (MRI/MRA) and digital subtraction angiography (DSA) in patients with non-traumatic intracerebral haemorrhage? Methods This

  12. Computed tomography angiography in patients with active gastrointestinal bleeding

    International Nuclear Information System (INIS)

    Reis, Fatima Regina Silva; D'Ippolito, Giuseppe

    2015-01-01

    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)

  13. 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)

  14. Approaches to tobacco control: the evidence base.

    Science.gov (United States)

    Aquilino, M Lober; Lowe, J B

    2004-02-01

    Tobacco production, distribution, and use are international issues with significant health and economic implications. This paper provides an overview of the effective approaches to tobacco control including decreasing demand for tobacco products through taxation, consumer education, research, bans on advertising and promotion, warning labels, and restrictions on public smoking. The effectiveness of reducing the supply of tobacco products through prohibition, restrictions on youth access, crop substitution, trade restrictions, and control of smuggling, will also be discussed. Decreasing smoking, particularly among young people, by preventing or delaying initiation, preventing regular use, and increasing cessation through behavioural approaches for all ages is reviewed. Cessation methods including pharmacological approaches, 'quitlines', Internet programmes, and the targeting of specific populations are discussed. Internet availability of tobacco products and sustainability of current efforts are presented as continuing challenges to tobacco control.

  15. 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

  16. A practice based approach to forest governance

    NARCIS (Netherlands)

    Arts, B.J.M.; Behagel, J.H.; Turnhout, E.; Koning, de J.; Bommel, van S.

    2014-01-01

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

  17. View based approach to forensic face recognition

    NARCIS (Netherlands)

    Dutta, A.; van Rootseler, R.T.A.; Veldhuis, Raymond N.J.; Spreeuwers, Lieuwe Jan

    Face recognition is a challenging problem for surveillance view images commonly encountered in a forensic face recognition case. One approach to deal with a non-frontal test image is to synthesize the corresponding frontal view image and compare it with frontal view reference images. However, it is

  18. Automated Generation of OCL Constraints: NL based Approach vs Pattern Based Approach

    Directory of Open Access Journals (Sweden)

    IMRAN SARWAR BAJWA

    2017-04-01

    Full Text Available This paper presents an approach used for automated generations of software constraints. In this model, the SBVR (Semantics of Business Vocabulary and Rules based semi-formal representation is obtained from the syntactic and semantic analysis of a NL (Natural Language (such as English sentence. A SBVR representation is easy to translate to other formal languages as SBVR is based on higher-order logic like other formal languages such as OCL (Object Constraint Language. The proposed model endows with a systematic and powerful system of incorporating NL knowledge on the formal languages. A prototype is constructed in Java (an Eclipse plug-in as a proof of the concept. The performance was tested for a few sample texts taken from existing research thesis reports and books

  19. Coronary Computed Tomographic Angiography at 80 kVp and Knowledge-Based Iterative Model Reconstruction Is Non-Inferior to that at 100 kVp with Iterative Reconstruction.

    Directory of Open Access Journals (Sweden)

    Joohee Lee

    Full Text Available The aims of this study were to compare the image noise and quality of coronary computed tomographic angiography (CCTA at 80 kVp with knowledge-based iterative model reconstruction (IMR to those of CCTA at 100 kVp with hybrid iterative reconstruction (IR, and to evaluate the feasibility of a low-dose radiation protocol with IMR. Thirty subjects who underwent prospective electrocardiogram-gating CCTA at 80 kVp, 150 mAs, and IMR (Group A, and 30 subjects with 100 kVp, 150 mAs, and hybrid IR (Group B were retrospectively enrolled after sample-size calculation. A BMI of less than 25 kg/m2 was required for inclusion. The attenuation value and image noise of CCTA were measured and the signal-to-noise ratio (SNR and contrast-to-noise ratio (CNR were calculated at the proximal right coronary artery and left main coronary artery. The image noise was analyzed using a non-inferiority test. The CCTA images were qualitatively evaluated using a four-point scale. The radiation dose was significantly lower in Group A than Group B (0.69 ± 0.08 mSv vs. 1.39 ± 0.15 mSv, p < 0.001. The attenuation values were higher in Group A than Group B (p < 0.001. The SNR and CNR in Group A were higher than those of Group B. The image noise of Group A was non-inferior to that of Group B. Qualitative image quality of Group A was better than that of Group B (3.6 vs. 3.4, p = 0.017. CCTA at 80 kVp with IMR could reduce the radiation dose by about 50%, with non-inferior image noise and image quality than those of CCTA at 100 kVp with hybrid IR.

  20. Attenuation-based kV pair selection in dual source dual energy computed tomography angiography of the chest: impact on radiation dose and image quality.

    Science.gov (United States)

    Renapurkar, Rahul D; Primak, Andrew; Azok, Joseph; Lempel, Jason; Tandon, Yasmeen; Bullen, Jennifer; Dong, Frank; Karim, Wadih; Graham, Ruffin

    2017-08-01

    The purpose of this study was to evaluate the impact of attenuation-based kilovoltage (kV) pair selection in dual source dual energy (DSDE)-pulmonary embolism (PE) protocol examinations on radiation dose savings and image quality. A prospective study was carried out on 118 patients with suspected PE. In patients in whom attenuation-based kV pair selection selected the 80/140Sn kV pair, the pre-scan 100/140Sn CTDIvol (computed tomography dose index volume) values were compared with the pre-scan 80/140Sn CTDIvol values. Subjective and objective image quality parameters were assessed. Attenuation-based kV pair selection switched to the 80/140Sn kV pair ("switched" cohort) in 63 out of 118 patients (53%). The mean 100/140Sn pre-scan CTDIvol was 8.8 mGy, while the mean 80/140Sn pre-scan CTDIvol was 7.5 mGy. The average estimated dose reduction for the "switched" cohort was 1.3 mGy (95% CI 1.2, 1.4; p quality. • Attenuation-based kV pair selection in dual energy examination is feasible. • It can offer radiation dose reduction to approximately 50% of patients. • Approximate 15% reduction in radiation dose was achieved using this technique. • The image quality is not compromised by use of attenuation-based kV pair selection.

  1. Dose selection based on physiologically based pharmacokinetic (PBPK) approaches.

    Science.gov (United States)

    Jones, Hannah M; Mayawala, Kapil; Poulin, Patrick

    2013-04-01

    Physiologically based pharmacokinetic (PBPK) models are built using differential equations to describe the physiology/anatomy of different biological systems. Readily available in vitro and in vivo preclinical data can be incorporated into these models to not only estimate pharmacokinetic (PK) parameters and plasma concentration-time profiles, but also to gain mechanistic insight into compound properties. They provide a mechanistic framework to understand and extrapolate PK and dose across in vitro and in vivo systems and across different species, populations and disease states. Using small molecule and large molecule examples from the literature and our own company, we have shown how PBPK techniques can be utilised for human PK and dose prediction. Such approaches have the potential to increase efficiency, reduce the need for animal studies, replace clinical trials and increase PK understanding. Given the mechanistic nature of these models, the future use of PBPK modelling in drug discovery and development is promising, however some limitations need to be addressed to realise its application and utility more broadly.

  2. Exposure doses to angiographers during interventional angiography

    International Nuclear Information System (INIS)

    Fukutomi, Yukimi; Yasuhara, Yoshifumi; Sugata, Shigenori; Fujii, Takashi; Kawakami, Toshiaki; Ikezoe, Junpei

    1997-01-01

    We report the exposure doses to angiographers during interventional angiography and the protective efficacy of protective aprons against X-rays in this study. The first (main) angiographer was exposed to the maximum dose of 1 μSv/min at the left chest area and lower abdominal area inside the protective apron. The second (assistant) angiographer was exposed to the maximum dose of 2 μSv/min at the left chest area and 1 μSv/min at the lower abdominal area. X-ray transmission ratio of the protective apron was 4.9 percent or less for UL25L, O percent for 0.35 mmPb and 4.3 percent or less for 0.5 mmPb. These results were lower than the dose equivalent limit based on the laws and ordinances. The protection capacities of these protective aprons proved to be sufficient. The exposure dose at the left extremity area outside the protective apron, however, was 24 times higher than at the left chest area inside. The data showed that it was not protected from scattered X-rays outside the protective apron. It is imperative to consider secondary protective material for the area outside the protective apron. Considering the risk of radiation, we need to better control exposure to angiographers. (author)

  3. Attenuation-based kV pair selection in dual source dual energy computed tomography angiography of the chest: impact on radiation dose and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Renapurkar, Rahul D.; Azok, Joseph; Lempel, Jason; Karim, Wadih; Graham, Ruffin [Thoracic Imaging, L10, Imaging Institute, Cleveland Clinic, Cleveland, OH (United States); Primak, Andrew [Siemens Medical Solutions, Malvern, PA (United States); Tandon, Yasmeen [Case Western Reserve University-Metro Health Medical Center, Department of Radiology, Cleveland, OH (United States); Bullen, Jennifer [Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH (United States); Dong, Frank [Section of Medical Physics, Cleveland Clinic, Cleveland, OH (United States)

    2017-08-15

    The purpose of this study was to evaluate the impact of attenuation-based kilovoltage (kV) pair selection in dual source dual energy (DSDE)-pulmonary embolism (PE) protocol examinations on radiation dose savings and image quality. A prospective study was carried out on 118 patients with suspected PE. In patients in whom attenuation-based kV pair selection selected the 80/140Sn kV pair, the pre-scan 100/140Sn CTDIvol (computed tomography dose index volume) values were compared with the pre-scan 80/140Sn CTDIvol values. Subjective and objective image quality parameters were assessed. Attenuation-based kV pair selection switched to the 80/140Sn kV pair (''switched'' cohort) in 63 out of 118 patients (53%). The mean 100/140Sn pre-scan CTDIvol was 8.8 mGy, while the mean 80/140Sn pre-scan CTDIvol was 7.5 mGy. The average estimated dose reduction for the ''switched'' cohort was 1.3 mGy (95% CI 1.2, 1.4; p < 0.001), representing a 15% reduction in dose. After adjusting for patient weight, mean attenuation was significantly higher in the ''switched'' vs. ''non-switched'' cohorts in all five pulmonary arteries and in all lobes on iodine maps. This study demonstrates that attenuation-based kV pair selection in DSDE examination is feasible and can offer radiation dose reduction without compromising image quality. (orig.)

  4. 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

  5. Prior knowledge-based approach for associating ...

    Science.gov (United States)

    Evaluating the potential human health and/or ecological risks associated with exposures to complex chemical mixtures in the ambient environment is one of the central challenges of chemical safety assessment and environmental protection. There is a need for approaches that can help to integrate chemical monitoring and bio-effects data to evaluate risks associated with chemicals present in the environment. We used prior knowledge about chemical-gene interactions to develop a knowledge assembly model for detected chemicals at five locations near two wastewater treatment plants. The assembly model was used to generate hypotheses about the biological impacts of the chemicals at each location. The hypotheses were tested using empirical hepatic gene expression data from fathead minnows exposed for 12 d at each location. Empirical gene expression data was also mapped to the assembly models to statistically evaluate the likelihood of a chemical contributing to the observed biological responses. The prior knowledge approach was able reasonably hypothesize the biological impacts at one site but not the other. Chemicals most likely contributing to the observed biological responses were identified at each location. Despite limitations to the approach, knowledge assembly models have strong potential for associating chemical occurrence with potential biological effects and providing a foundation for hypothesis generation to guide research and/or monitoring efforts relat

  6. Feature selection based classifier combination approach for ...

    Indian Academy of Sciences (India)

    based classifier combination is the simplest method in which final decision is that class for which maximum (greater than N/2) participating classifier vote, where N is the number of classifiers. 3.2b Decision templates: The method based on decision template, (Kuncheva et al 2001) firstly creates DT for each class using ...

  7. Feature selection based classifier combination approach for ...

    Indian Academy of Sciences (India)

    3.2c Dempster-Shafer rule based classifier combination: Dempster–Shafer (DS) method is based on the evidence theory, proposed by Glen Shafer as a way to represent cognitive knowledge. Here the probability is obtained using belief function instead of using the Bayesian distribution. Prob- ability values are assigned to a ...

  8. Problem-Based Learning Approaches in Meteorology

    Science.gov (United States)

    Charlton-Perez, Andrew James

    2013-01-01

    Problem-Based Learning, despite recent controversies about its effectiveness, is used extensively as a teaching method throughout higher education. In meteorology, there has been little attempt to incorporate Problem-Based Learning techniques into the curriculum. Motivated by a desire to enhance the reflective engagement of students within a…

  9. Complications with Outpatient Angiography and Interventional Procedures

    International Nuclear Information System (INIS)

    Young, Noel; Chi, Ka-Kit; Ajaka, Joe; McKay, Lesa; O'Neill, Diane; Wong, Kai Ping

    2002-01-01

    Purpose: To prospectively identify the complications, and rates of complication, in outpatient angiography and interventional procedures. Methods: There were 1050 consecutive patients, 646 men and 404 women, aged 17-89 years, with a total of 1239 procedures studied in a 2-year period, 1997 to 1999. Results: There were 560 cases of aorto-femoral angiography,resulting in 124 complications (22%), with pain or hematoma in 110.There were 206 cases of neck and cerebral angiography, resulting in 51 complications (25%), with pain and hematoma in 34, transient ischemic attack in 2 and cerebrovascular accident in 1. There were 197 interfentional procedures, with 177 being balloon dilatations, resulting in 68 complications (35%), with 2 having hematomas and 1 having hematoma/abscess requiring active treatment. There were 276 cases having various 'other' procedures (e.g., renal angiography),resulting in 65 complications (24%), with pain and hematoma in 61. No procedure-related death occurred. Eighteen cases (1.5%) had significant complications, with contrast allergy in eight. Conclusion: Outpatient angiography and intervention are relatively safe, with low significant complication rates

  10. Suprahyoid approach to base-of-tongue squamous cell carcinoma

    African Journals Online (AJOL)

    management such as percutaneous endoscopic gastrostomy. (PEG) feeds may be too expensive. Hence there is reliance on surgery and radiation therapy. Surgical approaches to the base of tongue include the trans-oral approach (CO2 laser resection or median glossotomy), mandibulotomy or the suprahyoid approach.

  11. A computationally efficient approach for template matching-based ...

    Indian Academy of Sciences (India)

    Image registration using template matching is an important step in image processing. In this paper, a simple, robust and computationally efficient approach is presented. The proposed approach is based on the properties of a normalized covariance matrix. The main advantage of the proposed approach is that the image ...

  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. Behavior based safety approach towards fire

    International Nuclear Information System (INIS)

    Suresh Kumar, R.

    2009-01-01

    The behavior of the individual who notice fire first is very important because it affect the safety of all occupants of the area. Human behavior on fire depends on variables of the buildings in which fire occurs and by the appearance of the fire when it is detected. Altruistic behavior of human being will help to handle the critical conditions due to fire emergencies. NPCIL have developed a culture of systematic approach to safeguard men and materials from fire by training and awareness. In our Nuclear Power Plants, we have an effective plan and system to test the plans. In each emergency exercises, the behavior of individuals will be monitored and recorded

  14. A systematic approach for component-based software development

    NARCIS (Netherlands)

    Guareis de farias, Cléver; van Sinderen, Marten J.; Ferreira Pires, Luis

    2000-01-01

    Component-based software development enables the construction of software artefacts by assembling prefabricated, configurable and independently evolving building blocks, called software components. This paper presents an approach for the development of component-based software artefacts. This

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

    International Nuclear Information System (INIS)

    Wang Wu; Li Minghua; Fang Chun; Wang Jue; Xiao Yunfeng

    2007-01-01

    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

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

    International Nuclear Information System (INIS)

    Lee, Yoo Jin; Lee, Jong Min; Lee, Hui Joong; Park, Ji Won

    2010-01-01

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

  17. Clinical application of peripheral angiography in infants

    International Nuclear Information System (INIS)

    Yu Juming; Fan Guoping; Zhong Weixing; Zhu Ming

    2005-01-01

    Objective: To evaluate the application and safety of angiography in infants. Methods: Eighteen infants with diagnosis of clinics, CT and MRI as hemangioma, hepatic and renal tumor and cerebral vascular diseases were undertaken digital subtraction angiography (DSA). Results: All the cases were found to have anomalous lesions including hemangioma racemosum in 3 cases, capillary hemangioma in 1, hepatoblastoma in 3, renal Wilm's tumor in 1, renal rhabdomyosarcoma in 1, liver arteriovenous fistula (AVF) in 1, Galenic arteriovenous malformation (AVM) in 1, Sturge-Weber Syndrome in 1, AVM OR AVF in the craniofacial region in 2 and pre-operation cerebral angiography of PNET in 2. Conclusions: DSA in infants is safe and reliable with extensive clinical application. (authors)

  18. Supplier selection an MCDA-based approach

    CERN Document Server

    Mukherjee, Krishnendu

    2017-01-01

    The purpose of this book is to present a comprehensive review of the latest research and development trends at the international level for modeling and optimization of the supplier selection process for different industrial sectors. It is targeted to serve two audiences: the MBA and PhD student interested in procurement, and the practitioner who wishes to gain a deeper understanding of procurement analysis with multi-criteria based decision tools to avoid upstream risks to get better supply chain visibility. The book is expected to serve as a ready reference for supplier selection criteria and various multi-criteria based supplier’s evaluation methods for forward, reverse and mass customized supply chain. This book encompasses several criteria, methods for supplier selection in a systematic way based on extensive literature review from 1998 to 2012. It provides several case studies and some useful links which can serve as a starting point for interested researchers. In the appendix several computer code wri...

  19. 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…

  20. A Task-Based Approach to Materials Development

    Science.gov (United States)

    Nunan, David

    2010-01-01

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

  1. Knowledge-Based Approaches: Two cases of applicability

    DEFF Research Database (Denmark)

    Andersen, Tom

    1997-01-01

    Basic issues of the term: A knowledge-based approach (KBA) are discussed. Two cases of applicable to KBA are presented, and its concluded that KBA is more than just IT.......Basic issues of the term: A knowledge-based approach (KBA) are discussed. Two cases of applicable to KBA are presented, and its concluded that KBA is more than just IT....

  2. 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

  3. 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…

  4. 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

  5. Advantages of condition-based maintenance approach

    International Nuclear Information System (INIS)

    Bareiss, J.; Roos, E.; Jovanovic, A.; Perunicic, M.; Balos, D.

    2004-01-01

    Pilot applications in EnBW steam boiler components and high-pressure pipe systems in the context of the European research project RIMAP (''Risk Based Inspection and Maintenance Procedures for European Industry'') showed that application of a risk-based maintenance strategy (e.g. RIMAP) will make the decision process more transparent and enable better condition-oriented maintenance. With regard to life management of the systems (availability, product quality), this appears to be more important than than the aspect of cost reduction in the maintenance sector, although the latter may not be unwelcome. (orig.) [de

  6. Invasive angiography and revascularization in patients with stable angina following prior coronary artery bypass grafting

    DEFF Research Database (Denmark)

    Joshi, Francis R; Biasco, Luigi; Pedersen, Frants

    2017-01-01

    BACKGROUND: There are limited data to guide the optimum approach to patients presenting with angina after coronary artery bypass grafting (CABG). Although often referred for invasive angiography, the effectiveness of this is unknown; angina may also result from diffuse distal or micro......-vascular coronary disease and it is not known how often targets for intervention are identified. METHODS: Retrospective review of 50,460 patients undergoing angiography in East Denmark between January 2010 and December 2014. Clinical and procedural data were prospectively stored in a regional electronic database....... Follow-up data were available for all patients, by means of records linked to each Danish social security number. RESULTS: In patients with prior CABG and stable angina (n = 2,309), diagnostic angiography led to revascularization in 574 (24.9%) cases. Chronic kidney disease (HR 1.93 [1.08-3.44], P = 0...

  7. Digital subtraction angiography of the thoracic aorta

    International Nuclear Information System (INIS)

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

    1984-01-01

    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

  8. 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.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    Background-Coronary computed tomographic angiography (CTA) and myocardial perfusion imaging (CTP) is a validated approach for detection and exclusion of flow-limiting coronary artery disease (CAD), but little data are available on gender-specific performance of these modalities. In this study, we...

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

    NARCIS (Netherlands)

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

    2014-01-01

    Spasm of the radial artery is the most important cause of failure to perform coronary angiography via the transradial approach. Spasmolytic cocktail may prevent radial artery spasm but is relatively contraindicated in patients with aortic stenosis or diminished left ventricular function. In this

  11. Radionuclide angiography in diagnosis of aortic dissection in comparison with CT scan and echogram

    International Nuclear Information System (INIS)

    Ohmine, Hiromi; Nishimura, Tsunehiko; Yamaguchi, Toshio; Hayashida, Kohei; Uehara, Toshio; Kozuka, Takahiro

    1982-01-01

    In 24 patients, we evaluated the usefulness of radioisotope study for aortic dissection. One of the most frequent findings was stasis of blood flow. Although the sensitivity was not so high as other noninvasive methods, we recognized that radionuclide angiography was able to perform safely, easily and informatibly for the detection of aortic dissection as a first choice of diagnostic approach. (author)

  12. 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.)

  13. 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.

  14. 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.

  15. Videodensitometric quantitative angiography after coronary balloon angioplasty, compared to edge-detection quantitative angiography and intracoronary ultrasound imaging

    NARCIS (Netherlands)

    Peters, R. J.; Kok, W. E.; Pasterkamp, G.; von Birgelen, C.; Prins, M. [=Martin H.; Serruys, P. W.

    2000-01-01

    AIMS: To assess the value of videodensitometric quantification of the coronary lumen after angioplasty by comparison to two other techniques of coronary artery lumen quantification. METHODS AND RESULTS: Videodensitometric quantitative angiography, edge detection quantitative angiography and 30 MHz

  16. 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

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

    Directory of Open Access Journals (Sweden)

    Ning Zhou

    2013-01-01

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

  18. Assessing Acid-Base Status: Physiologic Versus Physicochemical Approach.

    Science.gov (United States)

    Adrogué, Horacio J; Madias, Nicolaos E

    2016-11-01

    The physiologic approach has long been used in assessing acid-base status. This approach considers acids as hydrogen ion donors and bases as hydrogen ion acceptors and the acid-base status of the organism as reflecting the interaction of net hydrogen ion balance with body buffers. In the physiologic approach, the carbonic acid/bicarbonate buffer pair is used for assessing acid-base status and blood pH is determined by carbonic acid (ie, Paco 2 ) and serum bicarbonate levels. More recently, the physicochemical approach was introduced, which has gained popularity, particularly among intensivists and anesthesiologists. This approach posits that the acid-base status of body fluids is determined by changes in the dissociation of water that are driven by the interplay of 3 independent variables: the sum of strong (fully dissociated) cation concentrations minus the sum of strong anion concentrations (strong ion difference); the total concentration of weak acids; and Paco 2 . These 3 independent variables mechanistically determine both hydrogen ion concentration and bicarbonate concentration of body fluids, which are considered as dependent variables. Our experience indicates that the average practitioner is familiar with only one of these approaches and knows very little, if any, about the other approach. In the present Acid-Base and Electrolyte Teaching Case, we attempt to bridge this knowledge gap by contrasting the physiologic and physicochemical approaches to assessing acid-base status. We first outline the essential features, advantages, and limitations of each of the 2 approaches and then apply each approach to the same patient presentation. We conclude with our view about the optimal approach. Copyright © 2016 National Kidney Foundation, Inc. All rights reserved.

  19. Staffing in Radiotherapy: An Activity Based Approach

    International Nuclear Information System (INIS)

    2015-01-01

    Radiotherapy requires competent professional staff to ensure safe and effective patient treatment and management. There is a need to provide guidelines that recommend appropriate staffing levels to support the initiation of new services as well as the expansion or upgrade of existing services as even simple upgrades or replacement of existing equipment may have a significant impact on staffing needs. Similarly, the introduction of education and training programmes will require staffing adjustments. A calculation algorithm was developed to predict staffing levels based on the inputs that are known or can be easily estimated. This publication complements other IAEA publications used to support the initiation of basic radiation medicine services including Setting up a Radiotherapy Programme: Clinical, Medical Physics, Radiation Protection and Safety Aspects, published in 2008

  20. Wind Turbine Control: Robust Model Based Approach

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood

    . This is because, on the one hand, control methods can decrease the cost of energy by keeping the turbine close to its maximum efficiency. On the other hand, they can reduce structural fatigue and therefore increase the lifetime of the wind turbine. The power produced by a wind turbine is proportional...... to the square of its rotor radius, therefore it seems reasonable to increase the size of the wind turbine in order to capture more power. However as the size increases, the mass of the blades increases by cube of the rotor size. This means in order to keep structural feasibility and mass of the whole structure...... reasonable, the ratio of mass to size should be reduced. This trend results in more flexible structures. Control of the flexible structure of a wind turbine in a wind field with stochastic nature is very challenging. In this thesis we are examining a number of robust model based methods for wind turbine...

  1. Research-based approaches to nuclear education

    International Nuclear Information System (INIS)

    Donev, J.M.K.C.; Carpenter, Y.

    2014-01-01

    Teaching nuclear power requires an expert to communicate a significant number of abstract concepts from diverse disciplines, and assemble these into a larger intellectual framework for the students. Scholarly education research, particularly in individual science disciplines, has provided significant advances in teaching core subject material by breaking away from traditional lecturing. Thus far, however,little work has applied these results to introductory nuclear power classes. This paper explores a method of engaging introductory nuclear students deeply by using a combination of Socratic and mastery methods of teaching. Students develop conceptual understanding of the material through the group work and the use of diverse resources, including textbooks, online references, and computer models that encourage free exploration of these concepts. Marks have improved considerably, and students engage with the material at a significantly deeper level than in previous lecture-based iterations of this course. (author)

  2. 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.

  3. Identification of Underlying Causes of Spontaneous Submacular Hemorrhage by Indocyanine Green Angiography.

    Science.gov (United States)

    Kim, Hyesun; Lee, Sung Chul; Kim, Sang Myung; Lee, Ji Hwan; Koh, Hyoung Jun; Kim, Sung Soo; Byeon, Suk Ho; Kim, Min; Lee, Christopher Seungkyu

    2015-01-01

    To investigate the causes of acute spontaneous submacular hemorrhage with indocyanine green angiography (ICGA). Retrospective observation case series. A total of 51 eyes from 51 patients with newly developed spontaneous submacular hemorrhage were enrolled. Best-corrected visual acuity (BCVA), fundus photography, fluorescein angiography, spectral domain optical coherence tomography (OCT), and ICGA at baseline were analyzed. The extent of hemorrhage using fundus photography, height of hemorrhage, and central foveal thickness measured by OCT was analyzed to compare the diagnostic and nondiagnostic groups. The mean logarithm of the minimum angle of resolution (logMAR) BCVA at presentation was 1.21 ± 0.74 (Snellen equivalent, 20/324); the mean follow-up period was 23.9 ± 23.9 months. The cause of submacular hemorrhage was diagnosed in 43 of 51 eyes (84.3%) based on ICGA at presentation. The initial diagnoses were correct in 93% of eyes. In 3 cases, the initial diagnosis of age-related macular degeneration (AMD) was changed to polypoidal choroidal vasculopathy (PCV) based on follow-up ICGA. The central foveal thickness was significantly greater in the nondiagnostic group (1,102.4 vs. 666.7 μm, respectively; p = 0.008). The most common cause of submacular hemorrhage was neovascular AMD (52.9%), followed by PCV (37.3%), macroaneurysm (5.9%), and lacquer crack (3.9%). The mean final visual acuity was generally worse in patients with submacular hemorrhage with typical AMD (visual acuity 20/618) or PCV (visual acuity 20/240) compared to that in patients with retinal macroaneurysm (visual acuity 20/100) or lacquer crack (visual acuity 20/72). ICGA at initial presentation helps identify causes of submacular hemorrhage, allowing differential treatment approaches that may improve outcomes and safety.

  4. Information theory based approaches to cellular signaling.

    Science.gov (United States)

    Waltermann, Christian; Klipp, Edda

    2011-10-01

    Cells interact with their environment and they have to react adequately to internal and external changes such changes in nutrient composition, physical properties like temperature or osmolarity and other stresses. More specifically, they must be able to evaluate whether the external change is significant or just in the range of noise. Based on multiple external parameters they have to compute an optimal response. Cellular signaling pathways are considered as the major means of information perception and transmission in cells. Here, we review different attempts to quantify information processing on the level of individual cells. We refer to Shannon entropy, mutual information, and informal measures of signaling pathway cross-talk and specificity. Information theory in systems biology has been successfully applied to identification of optimal pathway structures, mutual information and entropy as system response in sensitivity analysis, and quantification of input and output information. While the study of information transmission within the framework of information theory in technical systems is an advanced field with high impact in engineering and telecommunication, its application to biological objects and processes is still restricted to specific fields such as neuroscience, structural and molecular biology. However, in systems biology dealing with a holistic understanding of biochemical systems and cellular signaling only recently a number of examples for the application of information theory have emerged. This article is part of a Special Issue entitled Systems Biology of Microorganisms. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Cognitive neuroscience of creativity: EEG based approaches.

    Science.gov (United States)

    Srinivasan, Narayanan

    2007-05-01

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

  6. Digital subtraction angiography of carotid bifurcation

    International Nuclear Information System (INIS)

    Vries, A.R. de.

    1984-01-01

    This study demonstrates the reliability of digital subtraction angiography (DSA) by means of intra- and interobserver investigations as well as indicating the possibility of substituting catheterangiography by DSA in the diagnosis of carotid bifurcation. Whenever insufficient information is obtained from the combination of non-invasive investigation and DSA, a catheterangiogram will be necessary. (Auth.)

  7. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Recently posted: Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ...

  8. MDCT angiography and transcatheter embolization in management ...

    African Journals Online (AJOL)

    Multidetector computed tomography (MDCT) allows direct demonstration and visualization of the bleeding source and its characterization. The information provided by MDCT angiography before attempts at therapeutic angiographic procedures leads to faster selective catheterization of bleeding vessels. The purpose of this ...

  9. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Radiology and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ... problems, recent surgeries and allergies. If you’re female and there’s a possibility that you’re pregnant ...

  10. Digital subtraction angiography: myths and reality

    International Nuclear Information System (INIS)

    Levin, D.C.

    1984-01-01

    Some of the claims made about digital subtraction angiography (DSA) when it was first developed have turned out to be greatly exaggerated, and some members of the radiologic community have become disillusioned with its capabilities. The author discusses some of the limitations of DSA, and concludes that the advantages of DSA outweigh its limitations

  11. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... your doctor for a mild sedative prior to the examination. For more information about Magnetic Resonance Angiography of MRA or any specific question you might have, visit Radiology Info dot org. Thank you for your time and for your attention! Spotlight Recently posted: How to Obtain and Share ...

  12. Post-mortem CT-coronary angiography

    DEFF Research Database (Denmark)

    Pøhlsgaard, Camilla; Leth, Peter Mygind

    2007-01-01

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

  13. Vascular anatomy in angiography for magnetic resonance

    International Nuclear Information System (INIS)

    Charry Lopez, Marco Luciano; Rivera Gomez, Juan Enrique

    1998-01-01

    A review of basic anatomical concepts and main variants, as well as some anatomical anomalies of the central nervous system vascularity, these concepts are considered essential for the interpretation of magnetic resonance angiography with time-of-flight (TOF) and phase-contrast (PC) methods

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

    Science.gov (United States)

    Godbold, Rosemary; Lees, Amanda

    2013-11-01

    It is now widely accepted that ethics is an essential part of educating health professionals. Despite a clear mandate to educators, there are differing approaches, in particular, how and where ethics is positioned in training programmes, underpinning philosophies and optimal modes of assessment. This paper explores varying practices and argues for a values based approach to ethics education. It then explores the possibility of using a web-based technology, the Values Exchange, to facilitate a values based approach. It uses the findings of a small scale study to signal the potential of the Values Exchange for engaging, meaningful and applied ethics education. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. 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...

  16. 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.

  17. Spiral CT angiography of splanchnic artery aneurysms. Technique and results

    International Nuclear Information System (INIS)

    Squillaci, E.; Ciolfi, M.G.; Maspes, F.; Simonetti, G.

    1999-01-01

    The aneurysm of visceral vessel are characterized by few or no symptoms and the diagnosis is often occasional. The authors investigated the usefulness of CT angiography in the diagnosis and preoperative assessment in this conditions. In the experience of the authors CT angiography can replace digital subtraction angiography in the diagnosis and preoperative work-up of visceral vessel aneurysms. CT angiography was superior to digital angiography to the evaluation of the lesion exact dimensions in case with large thrombotic component and diffuse wall calcifications [it

  18. Effect of the inquiry-based teaching approach on students ...

    African Journals Online (AJOL)

    This study investigated the effect of inquiry-based teaching approach on senior high school (SHS) students' conceptual understanding of circle theorems. It utilized mixed method approach involving quasi-experimental design in which 79 home economics students in two intact SHSs classes were purposively sampled and ...

  19. 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...

  20. Predicting footbridge vibrations using a probability-based approach

    DEFF Research Database (Denmark)

    Pedersen, Lars; Frier, Christian

    2017-01-01

    to modeling the action of a pedestrian. The paper employs a probability-based approach to modeling the action of a pedestrian by considering randomness in the behavior of the pedestrian crossing the footbridge. The paper describes the approach and studies implications (sensitivity) of selected decisions made...

  1. Effect of the inquiry-based teaching approach on students ...

    African Journals Online (AJOL)

    kofi.mereku

    This study investigated the effect of inquiry based teaching approach on senior high school. (SHS) students' conceptual understanding of circle theorems. It utilized mixed method approach involving quasi-experimental design in which 79 home economics students in two intact SHSs classes were purposively sampled and ...

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

    DEFF Research Database (Denmark)

    Spiriev, Toma; Poulsgaard, Lars; Fugleholm, Kåre

    2016-01-01

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

  3. An improved Hough transform-based fingerprint alignment approach

    CSIR Research Space (South Africa)

    Mlambo, CS

    2014-11-01

    Full Text Available An improved Hough Transform based fingerprint alignment approach is presented, which improves computing time and memory usage with accurate alignment parameter (rotation and translation) results. This is achieved by studying the strengths...

  4. Stochastic learning and optimization a sensitivity-based approach

    CERN Document Server

    Cao, Xi-Ren

    2007-01-01

    Performance optimization is vital in the design and operation of modern engineering systems. This book provides a unified framework based on a sensitivity point of view. It introduces new approaches and proposes new research topics.

  5. BASES OF COMPETENCE APPROACH IN COMPUTER SCIENCE TEACHER TRAINING

    Directory of Open Access Journals (Sweden)

    Kateryna R. Kovalska

    2010-08-01

    Full Text Available In the article the analysis of methodological and theoretical bases of competence approach has been made. It is given the structure and classification of computer science teacher competences.

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

    NARCIS (Netherlands)

    dr. Martijn Zoet; Stijn Hoppenbrouwers; Inge van de Weerd; Johan Versendaal

    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

  7. A Formal Reuse-Based Approach for Interactively Designing Organizations

    NARCIS (Netherlands)

    Jonker, C.M.; Treur, J.; Yolum, P.; Odell, J.; Giorgini, P.; Müller, J.P.

    2005-01-01

    Multiagent organizations provide a powerful way for developing multiagent systems. This paper presents a methodology for designing organizations based on formal specification of requirements for organizational behavior and requirements refinement related to organizational structure. The approach

  8. 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.

  9. 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.

  10. Multislice CT coronary angiography: how to do it and what is the current clinical performance?

    International Nuclear Information System (INIS)

    Cademartiri, Filippo; Runza, Giuseppe; Schuijf, Joanne D.; Mollet, Nico R.; Feyter, Pim J. de; Malagutti, Patrizia; Bax, Jeroen J.

    2005-01-01

    The introduction of multislice computed tomography (MSCT) has allowed non-invasive coronary angiography. Although widely applied, extensive information on technical details of the technique is lacking. This survey offers detailed information on patient preparation, data acquisition, reconstruction and interpretation. In addition, a summary of the available studies using MSCT for non-invasive angiography is provided. Based on pooled analysis of direct comparisons between MSCT and invasive angiography, the weighted mean sensitivity and specificity of current 16-slice MSCT for the detection of coronary artery disease are 88% and 96%, respectively. At present, the technique is particularly well suited for reliable exclusion of coronary artery disease. It is important to emphasise that MSCT only provides anatomical images, visualising the presence of atherosclerosis; information on the haemodynamic significance of these lesions (i.e. ischaemia) cannot be derived. (orig.)

  11. Diagnostic Accuracy of Coronary CT Angiography for the Evaluation of Bioresorbable Vascular Scaffolds

    DEFF Research Database (Denmark)

    Collet, Carlos; Chevalier, Bernard; Cequier, Angel

    2018-01-01

    : 44 to 90) and a specificity of 82% (95% CI: 75 to 87). The diagnostic accuracy of coronary CTA was similar to coronary angiography in its ability to identify patients with a significant lesion based on the IVUS criteria (p = 0.75). CONCLUSIONS: Coronary CTA has good diagnostic accuracy to detect in-scaffold...... luminal obstruction and to assess luminal dimensions after BVS implantation. Coronary angiography and coronary CTA yielded similar diagnostic accuracy to identify the presence and severity of obstructive disease. Coronary CTA might become the method of choice for the evaluation of patients treated......OBJECTIVES: To assess the diagnostic accuracy of coronary computed tomography angiography (CTA) for bioresorbable vascular scaffold (BVS) evaluation. BACKGROUND: Coronary CTA has emerged as a noninvasive method to evaluate patients with suspected or established coronary artery disease...

  12. Mapping site-based construction workers’ motivation: Expectancy theory approach

    OpenAIRE

    Ghoddousi, Parviz; Bahrami, Nima; Chileshe, Nicholas; Hosseini, M.Reza

    2014-01-01

    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...

  13. A model-data based systems approach to process intensification

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    . Their developments, however, are largely due to experiment based trial and error approaches and while they do not require validation, they can be time consuming and resource intensive. Also, one may ask, can a truly new intensified unit operation be obtained in this way? An alternative two-stage approach is to apply...... a model-based synthesis method to systematically generate and evaluate alternatives in the first stage and an experiment-model based validation in the second stage. In this way, the search for alternatives is done very quickly, reliably and systematically over a wide range, while resources are preserved...... for focused validation of only the promising candidates in the second-stage. This approach, however, would be limited to intensification based on “known” unit operations, unless the PI process synthesis/design is considered at a lower level of aggregation, namely the phenomena level. That is, the model-based...

  14. ROLE OF ULTRASONOGRAPHY, CONVENTIONAL ANGIOGRAPHY, CT AND CT ANGIOGRAPHY IN ASSESSMENT OF MESENTERIC ISCHAEMIA

    Directory of Open Access Journals (Sweden)

    Reena

    2016-05-01

    Full Text Available AIM The aim of the study was to evaluate efficacy, sensitivity, specificity of ultrasonography, conventional angiography, CT Angiography in mesenteric ischaemia. MATERIALS AND METHODS Prospective study was performed. 35 patients with clinically suspected mesenteric ischaemia were included in the study. The study was conducted from month of November 2013 to August 2015. The patients age ranged from 35 to 70 years (Mean age was 57±11.2 years. All cases met the criteria of acute nontraumatic or chronic abdominal pain and suspected mesenteric vascular ischaemia. All 35 cases were evaluated in surgery department, then underwent USG, conventional angiography, CTA. Out of 20 patients, 2 patients were inconclusive and 4 patients had other findings of abdominal pain. USG and CT angiographic findings were correlated with surgical findings in acute mesenteric ischaemia (AMI cases & conventional angiography in chronic mesenteric ischaemia (CMI cases. RESULT Ultrasonography has lower sensitivity and high specificity. Conventional angiography has moderate sensitivity and high specificity. CT angiography is highly sensitive and specific in detecting mesenteric ischaemia. CONCLUSION Conventional angiography is considered as the gold standard test for patients with acute and chronic mesenteric ischaemia except for hemodynamically unstable patients with acute mesenteric ischaemia. CTA is an emerging diagnostic test with high sensitivity and specificity in the setting of both acute and chronic mesenteric ischaemia and should be considered the first-line imaging test. CT can also accurately assess for other causes of acute and chronic abdominal pain, and it provides excellent anatomic mapping of the mesenteric vasculature, which is essential in the preoperative planning. US of the abdomen with Doppler waveform analysis can depict proximal mesenteric thrombosis and secondary signs of bowel compromise, but it is limited in the diagnosis of distal occlusions

  15. 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...

  16. 3D morphometry using automated aortic segmentation in native MR angiography: an alternative to contrast enhanced MRA?

    Science.gov (United States)

    Müller-Eschner, Matthias; Müller, Tobias; Biesdorf, Andreas; Wörz, Stefan; Rengier, Fabian; Böckler, Dittmar; Kauczor, Hans-Ulrich; Rohr, Karl; von Tengg-Kobligk, Hendrik

    2014-04-01

    Native-MR angiography (N-MRA) is considered an imaging alternative to contrast enhanced MR angiography (CE-MRA) for patients with renal insufficiency. Lower intraluminal contrast in N-MRA often leads to failure of the segmentation process in commercial algorithms. This study introduces an in-house 3D model-based segmentation approach used to compare both sequences by automatic 3D lumen segmentation, allowing for evaluation of differences of aortic lumen diameters as well as differences in length comparing both acquisition techniques at every possible location. Sixteen healthy volunteers underwent 1.5-T-MR Angiography (MRA). For each volunteer, two different MR sequences were performed, CE-MRA: gradient echo Turbo FLASH sequence and N-MRA: respiratory-and-cardiac-gated, T2-weighted 3D SSFP. Datasets were segmented using a 3D model-based ellipse-fitting approach with a single seed point placed manually above the celiac trunk. The segmented volumes were manually cropped from left subclavian artery to celiac trunk to avoid error due to side branches. Diameters, volumes and centerline length were computed for intraindividual comparison. For statistical analysis the Wilcoxon-Signed-Ranked-Test was used. Average centerline length obtained based on N-MRA was 239.0±23.4 mm compared to 238.6±23.5 mm for CE-MRA without significant difference (P=0.877). Average maximum diameter obtained based on N-MRA was 25.7±3.3 mm compared to 24.1±3.2 mm for CE-MRA (P<0.001). In agreement with the difference in diameters, volumes obtained based on N-MRA (100.1±35.4 cm(3)) were consistently and significantly larger compared to CE-MRA (89.2±30.0 cm(3)) (P<0.001). 3D morphometry shows highly similar centerline lengths for N-MRA and CE-MRA, but systematically higher diameters and volumes for N-MRA.

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

    Directory of Open Access Journals (Sweden)

    Aronson Alan R

    2010-11-01

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

  18. Rights-Based Approach: The Hub of Sustainable Development

    Science.gov (United States)

    Choondassery, Yesudas

    2017-01-01

    A rights-based approach to the environmental issues has been gaining momentum since the United Nations' Environmental Agency proposed a new rights-based agenda for sustainable development in the document, "Transforming Our World: The 2030 Agenda for Sustainable Development" (UN, 2015). Our moral responsibility toward the environment is…

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

    Science.gov (United States)

    Chien, Chin-Wen

    2014-01-01

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

  20. A Database Approach to Content-based XML retrieval

    NARCIS (Netherlands)

    Hiemstra, Djoerd

    2003-01-01

    This paper describes a rst prototype system for content-based retrieval from XML data. The system's design supports both XPath queries and complex information retrieval queries based on a language modelling approach to information retrieval. Evaluation using the INEX benchmark shows that it is

  1. A strength-based approach to athlete engagement: an exploratory ...

    African Journals Online (AJOL)

    Strength-based interventions have proven effective in the sport and athletic environment in a number of studies. However, few studies have investigated the effect of an integrated strength-based approach on positive athlete outcomes. This study investigated the effect of team-strength use and individual strength use on ...

  2. Implementing an outcomes-based approach to university essay writing

    African Journals Online (AJOL)

    In this article we present a case study to illustrate and reflect on the process of developing an outcomes‑based approach to essay writing in a university Economics 101 course. We argue that lecturers need support in the process of changing curricula and developing student writing to meet outcomes-based education policy ...

  3. Implementing Project Based Learning Approach to Graphic Design Course

    Science.gov (United States)

    Riyanti, Menul Teguh; Erwin, Tuti Nuriah; Suriani, S. H.

    2017-01-01

    The purpose of this study was to develop a learning model based Commercial Graphic Design Drafting project-based learning approach, was chosen as a strategy in the learning product development research. University students as the target audience of this model are the students of the fifth semester Visual Communications Design Studies Program…

  4. A knowledge-based approach for recognition of handwritten Pitman ...

    Indian Academy of Sciences (India)

    The paper describes a knowledge-based approach for the recognition of PSL strokes. Information about location and the direction of the starting point and final point of strokes are considered the knowledge base for recognition of strokes. The work comprises preprocessing, determination of starting and final points, ...

  5. A Skill-Based Approach to Teaching Group Counseling Interventions.

    Science.gov (United States)

    Toth, Paul L.; Stockton, Rex

    1996-01-01

    Investigates the use of a skill-based training curriculum as it relates to group counselor education. A pilot study is presented that uses three basic elements of group counselor training: didactic, observational, and experiential. The pilot study suggests how group interventions might be taught using a microcounseling-type skill-based approach.…

  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. Value of digital angiography as a substitute for film angiography in comparison with DSA

    International Nuclear Information System (INIS)

    Langer, M.; Mitsch, E.; Zwicker, C.; Scholz, A.; Felix, R.; Langer, R.

    1988-01-01

    The authors performed a prospective study to evaluate whether digital angiography (DA) can provide diagnostic image quality to reduce the need for film studies. The study is based on more than 100 arterial DSA examinations that were intra- and interindividually compared with the DA studies of the same arteries. It was demonstrated that DA with the same quantity of contrast medium as DSA is diagnostic in 80% of cases for abdominal, pelvic, and femoral arteries and in 85% for brachial arteries but in only 56% for carotid arteries if an aortic arch injection is performed. For all examinations, image quality with DSA was excellent in 86%, good in 9%, and diagnostic in 5%, with DA, it was excellent in 5%, good in 49%, diagnostic in 22%, and bad in 24% (90% of these were supraaortic studies). The results of this study indicate that it is worth trying a DA study when DSA is nondiagnostic because of artifacts, if a selective intraarterial contrast medium injection can be performed

  8. SEARCHING AND TRACKING OF LOCATION BY PROXY BASED APPROACH

    Directory of Open Access Journals (Sweden)

    K. Nirmala

    2017-01-01

    Full Text Available Location based services became an important application in recent world. Users can search a location using smart phones and can also track the location. It is also possible for the users to retrieve information about the nearest location. The objective of this paper is to reduce the respond time of the server for the user queries. A proxy based approach is proposed to reduce the waiting time of the user and to increase the information about the location. Many location based services, provides details about the user queries. The proxy based approach creates an Estimated Valid Region which reduces the number of queries approaching the server there by reducing the waiting time of the mobile clients due to server load.

  9. Angiography in the region of the foot

    International Nuclear Information System (INIS)

    Zeitler, E.

    1984-01-01

    It is reported on technique, incidence and findings of angiography of the foot which provided magnifying angiography and non-ionic contrast media are used, is especially qualified for the differentiation of diabetic and non-diabetic angiopathies as well as for the identification of peripherical embolizations and digital arterial occlusions at thrombocytosis or polycythemia. The arteries of the foot represent the peripherical outflow at peripherical reconstructive performances at the lower leg and have to be studied prior to such reconstructive surgical interventions. The different localization of arterial obliterations and changes of the walls in diabetics of stage I-IV according to Fontaine shows the particularly large number of vascular-pathological findings in arteries of the lower leg and foot in diabetics with arterial occlusive diseases of stage III and IV. Therefore, the unfavourable prognoses of arterial occlusive diseases in diabetics have also to be made for peripherical arterial obliterations of the foot and lower leg. (orig.) [de

  10. Intraoperative digital angiography: Peripheral vascular applications

    International Nuclear Information System (INIS)

    Bell, K.; Reifsteck, J.E.; Binet, E.F.; Fleisher, H.J.

    1986-01-01

    Intraoperative digital angiography is the procedure of choice for the peripheral vascular surgeon who wishes to evaluate his results before terminating anesthesia. Two operating suites at the John L. McClellan Memorial Veterans Hospital are equipped with permanent ceiling-mounted Philips C-arm fluoroscopes and share an ADAC 4100 digital angiographic system. In the last 18 months, 40 peripheral vascular intraoperative digital angiographic procedures have been performed, in all but two cases using direct arterial puncture. In 65% of cases, the intraoperative study showed no significant abnormality. In 12.5%, minor abnormalities not requiring reoperation were seen. In 22.5% of cases, the intraoperative digital angiogram revealed a significant abnormality requiring immediate operative revision. None of the patients who underwent reoperation experienced postoperative sequelae. Intraoperative digital angiography is useful in identifying complications of peripheral vascular operations

  11. Angiography of histopathologic variants of synovial sarcoma

    International Nuclear Information System (INIS)

    Lois, J.F.; Fischer, H.J.; Mirra, J.M.; Gomes, A.S.; California Univ., Los Angeles

    1986-01-01

    Synovial sarcomas are rare soft tissue tumors which histopathologically can be divided into monophasic, biphasic and mixed variants. As part of a protocol for intra-arterial chemotherapy 12 patients with biopsy proven synovial sarcoma underwent angiography. The angiograms on these patients were reviewed to determine whether synovial sarcomas and their variants demonstrated a characteristic angiographic appearance. Synovial sarcomas appeared angiographically as soft tissue masses which showed a fine network of tumor vessels with an inhomogeneous capillary blush. Their degree of vascularity varied according to their histopathology. Monophasic synovial sarcomas demonstrated in general a higher degree of neovascularity than the biphasic form. This finding was also suggested by histopathologic analysis of the vessels in the tumor. Although angiography did not show a distinctive vascular pattern it may be useful to evaluate tumor size and vascularity. (orig.)

  12. Angiography in distal spleno-renal shunts

    International Nuclear Information System (INIS)

    Wittrich, G.; Czembirek, H.; Appel, W.; Funovics, J.; Lechner, G.; Vienna Univ.; Vienna Univ.

    1980-01-01

    The conception of Warren's Shunt - selective decompression of esophageal varices while maintaining prograde portal flow - was controlled by pre- and postoperative angiographic examinations on 12 patients: No change in portal perfusion was established angiographically in ten of the patients. Two patients developed aneurysmatic, arterio-portal fistulae as a result of postoperative portal decompression. In one of these cases, a thrombosis of the portal vein with hepatofugal perfusion of the left gastric vein was detected. The postoperative examinations indicated functioning shunts in 9 out of 12 patients. These results formed the basis for the discussion regarding the value of visceral angiography in the selection of the surgical technique and regarding its value in control of therapy. Surgical questions concerning the visceral vascular anatomy can be answered sufficiently. Furthermore, celiac and mesenteric angiography yield information on portal hemodynamics. Nevertheless, the additional application of invasive scintigraphy seems to be necessary for establishing quantitative radiological parameters of prognostic relevance. (orig.) [de

  13. Angiography in distal spleno-renal shunts

    Energy Technology Data Exchange (ETDEWEB)

    Wittrich, G.; Czembirek, H.; Appel, W.; Funovics, J.; Lechner, G.

    1980-11-01

    The conception of Warren's Shunt - selective decompression of esophageal varices while maintaining prograde portal flow - was controlled by pre- and postoperative angiographic examinations on 12 patients: No change in portal perfusion was established angiographically in ten of the patients. Two patients developed aneurysmatic, arterio-portal fistulae as a result of postoperative portal decompression. In one of these cases, a thrombosis of the portal vein with hepatofugal perfusion of the left gastric vein was detected. The postoperative examinations indicated functioning shunts in 9 out of 12 patients. These results formed the basis for the discussion regarding the value of visceral angiography in the selection of the surgical technique and regarding its value in control of therapy. Surgical questions concerning the visceral vascular anatomy can be answered sufficiently. Furthermore, celiac and mesenteric angiography yield information on portal hemodynamics. Nevertheless, the additional application of invasive scintigraphy seems to be necessary for establishing quantitative radiological parameters of prognostic relevance.

  14. Deep Vein Thrombosis after Coronary Angiography

    Directory of Open Access Journals (Sweden)

    Vivek Singh Guleria

    2015-01-01

    Full Text Available Deep vein thrombosis (DVT is a rare but potentially serious complication of coronary angiography (CAG, incidence being just 0.05%. Only a few clinical cases of DVT after diagnostic transfemoral catheterization have been reported. Here, we describe the case of a 54-year-old woman who developed significant DVT after CAG without venous thromboembolism (VTE and, which was treated with anticoagulants.

  15. Contrast settling in cerebral aneurysm angiography

    International Nuclear Information System (INIS)

    Wang Zhijie; Hoffmann, Kenneth R; Guterman, Lee R; Wang Zhou; Rudin, Stephen; Meng Hui

    2005-01-01

    During angiography, blood flow is visualized with a radiopaque contrast agent, which is denser than blood. In complex vasculature, such as cerebral saccular aneurysms, the density difference may produce an appreciable gravity effect, where the contrast material separates from blood and settles along the gravity direction. Although contrast settling has been occasionally reported before, the fluid mechanics behind it have not been explored. Furthermore, the severity of contrast settling in cerebral aneurysms varies significantly from case to case. Therefore, a better understanding of the physical principles behind this phenomenon is needed to evaluate contrast settling in clinical angiography. In this study, flow in two identical groups of sidewall aneurysm models with varying parent-vessel curvature was examined by angiography. Intravascular stents were deployed into one group of the models. To detect contrast settling, we used lateral view angiography. Time-intensity curves were analysed from the angiographic data, and a computational fluid dynamic analysis was conducted. Results showed that contrast settling was strongly related to the local flow dynamics. We used the Froude number, a ratio of flow inertia to gravity force, to characterize the significance of gravity force. An aneurysm with a larger vessel curvature experienced higher flow, which resulted in a larger Froude number and, thus, less gravitational settling. Addition of a stent reduced the aneurysmal flow, thereby increasing the contrast settling. We found that contrast settling resulted in an elevated washout tail in the time-intensity curve. However, this signature is not unique to contrast settling. To determine whether contrast settling is present, a lateral view should be obtained in addition to the anteroposterior (AP) view routinely used clinically so as to rule out contrast settling and hence to enable a valid time-intensity curve analysis of blood flow in the aneurysm

  16. State of the art: coronary angiography.

    Science.gov (United States)

    Collet, Carlos; Grundeken, Maik J; Asano, Taku; Onuma, Yoshinobu; Wijns, William; Serruys, Patrick W

    2017-08-25

    In the early days of coronary angiography, the precise quantification of luminal narrowing was challenging. The introduction of balloon angioplasty (percutaneous transluminal coronary angioplasty [PTCA]) by Andreas Grüntzig in 1977 was perhaps the greatest incentive to the development of quantitative coronary angiography (QCA). QCA has played a crucial role in evaluating interventional techniques and assessing the results of new technologies. With the advent of drug-eluting stents (DES), QCA metrics such as late lumen loss and diameter stenosis (restenosis) proved to be instrumental in assessing new technologies. Refinements in QCA with the advent of dedicated bifurcation analysis and three-dimensional (3D) QCA have broadened the application of QCA. Beyond angiographic metrics, new developments in the field of QCA have introduced the functional component in the assessment of coronary lesions. Angiography-derived fractional flow reserve (FFR) may be a good tool for diagnosing ischaemia-producing lesions in patients with non-complex coronary artery disease. Furthermore, the incremental functional information can be used to expand the traditional late lumen loss (LLL) and restenosis concepts.

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

    Science.gov (United States)

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

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

  18. Pedestrian safety management using the risk-based approach

    OpenAIRE

    Romanowska Aleksandra; Jamroz Kazimierz; Kustra Wojciech

    2017-01-01

    The paper presents a concept of a multi-level pedestrian safety management system. Three management levels are distinguished: strategic, tactical and operational. The basis for the proposed approach to pedestrian safety management is a risk-based method. In the approach the elements of behavioural and systemic theories were used, allowing for the development of a formalised and repeatable procedure integrating the phases of risk assessment and response to the hazards of road crashes involving...

  19. 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...

  20. Computer based approach to fatigue analysis and design

    International Nuclear Information System (INIS)

    Comstock, T.R.; Bernard, T.; Nieb, J.

    1979-01-01

    An approach is presented which uses a mini-computer based system for data acquisition, analysis and graphic displays relative to fatigue life estimation and design. Procedures are developed for identifying an eliminating damaging events due to overall duty cycle, forced vibration and structural dynamic characteristics. Two case histories, weld failures in heavy vehicles and low cycle fan blade failures, are discussed to illustrate the overall approach. (orig.) 891 RW/orig. 892 RKD [de

  1. Robotic digital subtraction angiography systems within the hybrid operating room.

    Science.gov (United States)

    Murayama, Yuichi; Irie, Koreaki; Saguchi, Takayuki; Ishibashi, Toshihiro; Ebara, Masaki; Nagashima, Hiroyasu; Isoshima, Akira; Arakawa, Hideki; Takao, Hiroyuki; Ohashi, Hiroki; Joki, Tatsuhiro; Kato, Masataka; Tani, Satoshi; Ikeuchi, Satoshi; Abe, Toshiaki

    2011-05-01

    Fully equipped high-end digital subtraction angiography (DSA) within the operating room (OR) environment has emerged as a new trend in the fields of neurosurgery and vascular surgery. To describe initial clinical experience with a robotic DSA system in the hybrid OR. A newly designed robotic DSA system (Artis zeego; Siemens AG, Forchheim, Germany) was installed in the hybrid OR. The system consists of a multiaxis robotic C arm and surgical OR table. In addition to conventional neuroendovascular procedures, the system was used as an intraoperative imaging tool for various neurosurgical procedures such as aneurysm clipping and spine instrumentation. Five hundred one neurosurgical procedures were successfully conducted in the hybrid OR with the robotic DSA. During surgical procedures such as aneurysm clipping and arteriovenous fistula treatment, intraoperative 2-/3-dimensional angiography and C-arm-based computed tomographic images (DynaCT) were easily performed without moving the OR table. Newly developed virtual navigation software (syngo iGuide; Siemens AG) can be used in frameless navigation and in access to deep-seated intracranial lesions or needle placement. This newly developed robotic DSA system provides safe and precise treatment in the fields of endovascular treatment and neurosurgery.

  2. Sixty-four slice spiral CT angiography does not predict the functional relevance of coronary artery stenoses in patients with stable angina

    International Nuclear Information System (INIS)

    Hacker, Marcus; Hack, Nicolas; Hahn, Klaus; Tiling, Reinhold; Jakobs, Tobias; Nikolaou, Konstantin; Becker, Christoph; Reiser, Maximilian; Ziegler, Franz von; Knez, Andreas; Koenig, Andreas; Klauss, Volker

    2007-01-01

    The aim of this study was to evaluate spiral multidetector computed tomography (MDCT) angiography using 64-slice technique in the detection of functionally relevant coronary artery stenoses (CAS). Thirty-eight patients (62±11 years, 28 men) with stable angina (26 with suspected and 12 with known coronary artery disease) were investigated using 64-slice MDCT angiography and gated myocardial perfusion SPECT (gated SPECT); a subgroup of 30 patients had additional invasive coronary angiography (ICA). Stenoses with luminal narrowing of ≥50% were defined as ''significant'' in MDCT angiography and ICA. MDCT angiography was compared with gated SPECT and the combination of gated SPECT plus ICA with respect to the detection of functionally relevant CAS. The sensitivity, specificity and negative and positive predictive values of MDCT angiography in detecting reversible perfusion defects on gated SPECT were 63%, 80%, 94% and 32%, respectively, in vessel-based analysis and 71%, 62%, 72% and 60%, respectively, in patient-based analysis. If only reversible perfusion defects on gated SPECT with CAS ≥50% on ICA were considered, the sensitivity, specificity and negative and positive predictive values were, respectively, 85%, 79%, 98% and 33% for vessel-based analysis and 85%, 59%, 83% and 61% for patient-based analysis. Sixty-four slice MDCT angiography failed to predict the functional relevance of CAS, but had a high negative predictive value in the exclusion of functionally relevant CAS in symptomatic patients. (orig.)

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

    DEFF Research Database (Denmark)

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

    2005-01-01

    . 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......In dealing with the strategic issues within a manufacturing system, it is necessary to facilitate formulating the composing elements of a set of strategic manufacturing practices and activity patterns that will support an enterprise to reinforce and increase its competitive advantage...... 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...

  4. A model-data based systems approach to process intensification

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    . Their developments, however, are largely due to experiment based trial and error approaches and while they do not require validation, they can be time consuming and resource intensive. Also, one may ask, can a truly new intensified unit operation be obtained in this way? An alternative two-stage approach is to apply...... for focused validation of only the promising candidates in the second-stage. This approach, however, would be limited to intensification based on “known” unit operations, unless the PI process synthesis/design is considered at a lower level of aggregation, namely the phenomena level. That is, the model......-based synthesis method must employ models at lower levels of aggregation and through combination rules for phenomena, generate (synthesize) new intensified unit operations. An efficient solution procedure for the synthesis problem is needed to tackle the potentially large number of options that would be obtained...

  5. Lessons learned about art-based approaches for disseminating knowledge.

    Science.gov (United States)

    Bruce, Anne; Makaroff, Kara L Schick; Sheilds, Laurene; Beuthin, Rosanne; Molzahn, Anita; Shermak, Sheryl

    2013-01-01

    To present a case example of using an arts-based approach and the development of an art exhibit to disseminate research findings from a narrative research study. Once a study has been completed, the final step of dissemination of findings is crucial. In this paper, we explore the benefits of bringing nursing research into public spaces using an arts-based approach. Findings from a qualitative narrative study exploring experiences of living with life-threatening illnesses. Semi-structured in-depth interviews were conducted with 32 participants living with cancer, chronic renal disease, or HIV/AIDS. Participants were invited to share a symbol representing their experience of living with life-threatening illness and the meaning it held for them. The exhibit conveyed experiences of how people story and re-story their lives when living with chronic kidney disease, cancer or HIV. Photographic images of symbolic representations of study participants' experiences and poetic narratives from their stories were exhibited in a public art gallery. The theoretical underpinning of arts-based approaches and the lessons learned in creating an art exhibit from research findings are explored. Creative art forms for research and disseminating knowledge offer new ways of understanding and knowing that are under-used in nursing. Arts-based approaches make visible patients' experiences that are often left unarticulated or hidden. Creative dissemination approaches such as art exhibits can promote insight and new ways of knowing that communicate nursing research to both public and professional audiences.

  6. 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.......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...

  7. Cost effectiveness of coronary angiography and calcium scoring using CT and stress MRI for diagnosis of coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Dewey, Marc; Hamm, Bernd [Humboldt University, Department of Radiology, Charite, Medical School, Berlin (Germany)

    2007-05-15

    We compared the cost effectiveness of recent approaches [coronary angiography and calcium scoring using computed tomography (CT) and stress magnetic resonance imaging (MRI)] to the diagnosis of coronary artery disease (CAD) with those of the traditional diagnostic modalities [conventional angiography (CATH), exercise ECG, and stress echocardiography] using a decision tree model. For patients with a 10% to 50% pretest likelihood of coronary artery disease, non-invasive coronary angiography using CT was the most cost effective approach, with costs per correctly identified CAD patient of EUR4,435 (10% likelihood) to EUR1,469 (50% likelihood). Only for a pretest likelihood of 30% to 40% was calcium scoring using CT more cost effective than any of the traditional diagnostic modalities, while MRI was not cost effective for any pretest likelihood. At a pretest likelihood of 60%, CT coronary angiography and CATH were equally effective, while CATH was most cost effective for a pretest likelihood of at least 70%. In conclusion, up to a pretest likelihood for coronary artery disease of 50%, CT coronary angiography is the most cost-effective procedure, being superior to the other new modalities and the most commonly used traditional diagnostic modalities. With a very high likelihood for disease (above 60%), CATH is the most effective procedure from the perspective of society. (orig.)

  8. 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.)

  9. The anterior interhemispheric approach: a safe and effective approach to anterior skull base lesions.

    Science.gov (United States)

    Mielke, Dorothee; Mayfrank, Lothar; Psychogios, Marios Nikos; Rohde, Veit

    2014-04-01

    Many approaches to the anterior skull base have been reported. Frequently used are the pterional, the unilateral or bilateral frontobasal, the supraorbital and the frontolateral approach. Recently, endoscopic transnasal approaches have become more popular. The benefits of each approach has to be weighted against its complications and limitations. The aim of this study was to investigate if the anterior interhemispheric approach (AIA) could be a safe and effective alternative approach to tumorous and non-tumorous lesions of the anterior skull base. We screened the operative records of all patients with an anterior skull base lesion undergoing transcranial surgery. We have used the AIA in 61 patients. These were exclusively patients with either olfactory groove meningioma (OGM) (n = 43), ethmoidal dural arteriovenous fistula (dAVF) ( n = 6) or frontobasal fractures of the anterior midline with cerebrospinal fluid (CSF) leakage ( n = 12). Patient records were evaluated concerning accessibility of the lesion, realization of surgical aims (complete tumor removal, dAVF obliteration, closure of the dural tear), and approach related complications. The use of the AIA exclusively in OGMs, ethmoidal dAVFs and midline frontobasal fractures indicated that we considered lateralized frontobasal lesions not suitable to be treated successfully. If restricted to these three pathologies, the AIA is highly effective and safe. The surgical aim (complete tumor removal, complete dAVF occlusion, no rhinorrhea) was achieved in all patients. The complication rate was 11.5 % (wound infection (n = 2; 3.2 %), contusion of the genu of the corpus callosum, subdural hygroma, epileptic seizure, anosmia and asymptomatic bleed into the tumor cavity (n = 1 each). Only the contusion of the corpus callosum was directly related to the approach (1.6 %). Olfaction, if present before surgery, was preserved in all patients, except one (1.6 %). The AIA is an effective and a safe approach

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

    International Nuclear Information System (INIS)

    Ayyala, Rama S.; Lee, Edward Y.; Zurakowski, David

    2015-01-01

    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. 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.)

  13. A proven knowledge-based approach to prioritizing process information

    Science.gov (United States)

    Corsberg, Daniel R.

    1991-01-01

    Many space-related processes are highly complex systems subject to sudden, major transients. In any complex process control system, a critical aspect is rapid analysis of the changing process information. During a disturbance, this task can overwhelm humans as well as computers. Humans deal with this by applying heuristics in determining significant information. A simple, knowledge-based approach to prioritizing information is described. The approach models those heuristics that humans would use in similar circumstances. The approach described has received two patents and was implemented in the Alarm Filtering System (AFS) at the Idaho National Engineering Laboratory (INEL). AFS was first developed for application in a nuclear reactor control room. It has since been used in chemical processing applications, where it has had a significant impact on control room environments. The approach uses knowledge-based heuristics to analyze data from process instrumentation and respond to that data according to knowledge encapsulated in objects and rules. While AFS cannot perform the complete diagnosis and control task, it has proven to be extremely effective at filtering and prioritizing information. AFS was used for over two years as a first level of analysis for human diagnosticians. Given the approach's proven track record in a wide variety of practical applications, it should be useful in both ground- and space-based systems.

  14. 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...

  15. 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...

  16. A random-permutations-based approach to fast read alignment.

    Science.gov (United States)

    Lederman, Roy

    2013-01-01

    Read alignment is a computational bottleneck in some sequencing projects. Most of the existing software packages for read alignment are based on two algorithmic approaches: prefix-trees and hash-tables. We propose a new approach to read alignment using random permutations of strings. We present a prototype implementation and experiments performed with simulated and real reads of human DNA. Our experiments indicate that this permutations-based prototype is several times faster than comparable programs for fast read alignment and that it aligns more reads correctly. This approach may lead to improved speed, sensitivity, and accuracy in read alignment. The algorithm can also be used for specialized alignment applications and it can be extended to other related problems, such as assembly.More information: http://alignment.commons.yale.edu.

  17. Fuzzy axiomatic design approach based green supplier selection

    DEFF Research Database (Denmark)

    Kannan, Devika; Govindan, Kannan; Rajendran, Sivakumar

    2015-01-01

    proposes a multi-criteria decision-making (MCDM) approach called Fuzzy Axiomatic Design (FAD) to select the best green supplier for Singapore-based plastic manufacturing company. At first, the environmental criteria was developed along with the traditional criteria based on the literature review...... and company requirements. Next, the FAD methodology evaluates the requirements of both the manufacturer (design needs) and the supplier (functional needs), and because multiple criteria must be considered, a multi-objective optimization model of a fuzzy nature must be developed. The application...... of the proposed approach in the case company has been illustrated and the result of this study helps firm to establish the systematic approach to select the best green supplier within the set of criteria. When the proposed methodology is applied, it allows not only to select the most appropriate green supplier...

  18. 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...

  19. A Project-based Learning approach for teaching Robotics to ...

    African Journals Online (AJOL)

    In this research we used a project-based learning approach to teach robotics basics to undergraduate business computing students. The course coverage includes basic electronics, robot construction and programming using arduino. Students developed and tested a robot prototype. The project was evaluated using a ...

  20. Hidden Markov model-based approach for generation of Pitman ...

    Indian Academy of Sciences (India)

    Speech is one of the most basic means of human communication. ... human beings is carried out with the aid of communication and has facilitated the development ... Hidden Markov model-based approach for generation of PSL symbols. 279. Table 1. PSL basic strokes and English consonants. English consonant.

  1. Intelligent assembly time analysis, using a digital knowledge based approach

    NARCIS (Netherlands)

    Jin, Y.; Curran, R.; Butterfield, J.; Burke, R.; Welch, B.

    2009-01-01

    The implementation of effective time analysis methods fast and accurately in the era of digital manufacturing has become a significant challenge for aerospace manufacturers hoping to build and maintain a competitive advantage. This paper proposes a structure oriented, knowledge-based approach for

  2. A Review Of Risk-Based Approaches For Emerging Diseases ...

    African Journals Online (AJOL)

    A Review Of Risk-Based Approaches For Emerging Diseases Associated With Animal Source-Foods. ... Bulletin of Animal Health and Production in Africa ... Rapid urbanization, globalization and intensification of livestock production in developing countries are causing dramatic changes in food production, supply and ...

  3. What does an enquiry-based approach offer undergraduate ...

    African Journals Online (AJOL)

    Background. Physiotherapy students in their final year at Stellenbosch University (SU) complete a module that follows an enquiry-based learning (EBL) approach. This module exposes them to higher-order problem solving and was developed to facilitate independent self-directed learning and improved higher-order ...

  4. A phase-based approach to Russian free word order

    NARCIS (Netherlands)

    Dyakonova, M.

    2009-01-01

    In this book a syntactic account of Information Structure encoding is worked out which is based on the Derivation by Phase theory and the cartographic approach to the syntax-pragmatics interface. The analysis is developed on the basis of Information Structure encoding in Russian, a discourse

  5. MVMO-based approach for optimal placement and tuning of ...

    African Journals Online (AJOL)

    ... optimal placement and coordinated tuning of power system supplementary damping controllers (POCDCs). The effectiveness of the approach is evaluated based on the classical IEEE 39-bus (New England) test system. Numerical results include performance comparisons with other metaheuristic optimization techniques, ...

  6. The Task-Based Approach in Language Teaching

    Science.gov (United States)

    Sánchez, Aquilino

    2004-01-01

    The Task-Based Approach (TBA) has gained popularity in the field of language teaching since the last decade of the 20th Century and significant scholars have joined the discussion and increased the amount of analytical studies on the issue. Nevertheless experimental research is poor, and the tendency of some of the scholars is nowadays shifting…

  7. Evaluation of a Blog Based Parent Involvement Approach by Parents

    Science.gov (United States)

    Ozcinar, Zehra; Ekizoglu, Nihat

    2013-01-01

    Despite the well-known benefits of parent involvement in children's education, research clearly shows that it is difficult to effectively involve parents. This study aims to capture parents' views of a Blog Based Parent Involvement Approach (BPIA) designed to secure parent involvement in education by strengthening school-parent communication. Data…

  8. 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...

  9. Mobile Games for Learning: A Pattern-Based Approach

    NARCIS (Netherlands)

    Schmitz, Birgit

    2015-01-01

    The core concern of this thesis is the design of mobile games for learning. The conditions and requirements that are vital in order to make mobile games suitable and effective for learning environments are investigated. The base for exploration is the pattern approach as an established form of

  10. Non-frontal Model Based Approach to Forensic Face Recognition

    NARCIS (Netherlands)

    Dutta, A.; Veldhuis, Raymond N.J.; Spreeuwers, Lieuwe Jan

    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

  11. A concept-based approach to text categorization

    NARCIS (Netherlands)

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

    2005-01-01

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

  12. 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.

  13. a human rights-based approach to poverty reduction

    African Journals Online (AJOL)

    NWUuser

    poverty. This will be done firstly by discussing the human rights-based approach to poverty reduction,15 whereafter attention will be turned to access to medicines ... Benzeval et al "Relationships between Health, Income and Poverty" 78; Spicker et al Poverty 91; ...... Corrective and Distributive Justice (PULP Pretoria 2009) ...

  14. The ethical approach to evidence-based medicine

    African Journals Online (AJOL)

    Evidence-based medicine has had a major impact on health care in the last 30 years. This approach has lead to the critical appraisal of therapeutic knowledge. Archie Cochrane, an epidemiologist, gave a series of lectures in 1972 regarding his reflections on the effectiveness and efficiency of health services.1 He ...

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

    Directory of Open Access Journals (Sweden)

    Zahra Pourmovahed

    2016-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Pourmovahed Zahra

    2016-08-01

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

  17. Diagnostic Accuracy of Coronary CT Angiography for the Evaluation of Bioresorbable Vascular Scaffolds.

    Science.gov (United States)

    Collet, Carlos; Chevalier, Bernard; Cequier, Angel; Fajadet, Jean; Dominici, Marcello; Helqvist, Steffen; Van Boven, A J; Dudek, Dariusz; McClean, Dougal; Almeida, Manuel; Piek, Jan J; Tenekecioglu, Erhan; Bartorelli, Antonio; Windecker, Stephan; Serruys, Patrick W; Onuma, Yoshinobu

    2017-07-13

    To assess the diagnostic accuracy of coronary computed tomography angiography (CTA) for bioresorbable vascular scaffold (BVS) evaluation. Coronary CTA has emerged as a noninvasive method to evaluate patients with suspected or established coronary artery disease. The diagnostic accuracy of coronary CTA to evaluate angiographic outcomes after BVS implantation has not been well established. In the ABSORB II (A Bioresorbable Everolimus-Eluting Scaffold Versus a Metallic Everolimus-Eluting Stent II) study, patients were randomized either to receive treatment with the BVS or everolimus-eluting metallic stent. At the 3-year follow-up, 238 patients (258 lesions) treated with BVS underwent coronary angiography with intravascular ultrasound (IVUS) evaluation and coronary CTA. The diagnostic accuracy of coronary CTA was assessed by the area under the receiver-operating characteristic curve with coronary angiography and IVUS as references. The mean difference in coronary CTA-derived minimal luminal diameter was -0.14 mm (limits of agreement -0.88 to 0.60) with quantitative coronary angiography as reference, whereas the mean difference in minimal lumen area was 0.73 mm 2 (limits of agreement -1.85 to 3.30) with IVUS as reference. The per-scaffold diagnostic accuracy of coronary CTA for detecting stenosis based on coronary angiography diameter stenosis of ≥50% revealed an area under the receiver-operating characteristic curve of 0.88 (95% confidence interval [CI]: 0.82 to 0.92) with a sensitivity of 80% (95% CI: 28 to 99) and a specificity of 100% (95% CI: 98 to 100), whereas diagnostic accuracy based on IVUS minimal lumen area ≤2.5 mm 2 showed an area under the receiver-operating characteristic curve of 0.83 (95% CI: 0.77 to 0.88) with a sensitivity of 71% (95% CI: 44 to 90) and a specificity of 82% (95% CI: 75 to 87). The diagnostic accuracy of coronary CTA was similar to coronary angiography in its ability to identify patients with a significant lesion based on the

  18. OCT Angiography Compared to Fluorescein and Indocyanine Green Angiography in Chronic Central Serous Chorioretinopathy

    NARCIS (Netherlands)

    Teussink, M.M.; Breukink, M.B.; Grinsven, M.J.J.P. van; Hoyng, C.B.; Klevering, B.J.; Boon, C.J.F.; Jong, E.K.; Theelen, T.

    2015-01-01

    PURPOSE: Abnormal choroidal blood flow is considered important in the pathogenesis of chronic central serous chorioretinopathy (CSC). Optical coherence tomography (OCT) angiography can image ocular blood cell flow and could thus provide novel insights in disease mechanisms of CSC. We evaluated

  19. Noninvasive coronary angiography: agreement of multi-slice spiral computed tomography and selective catheter angiography.

    Science.gov (United States)

    Fine, Jeffrey J; Hopkins, Christie B; Hall, Patrick A X; Delphia, Robert E; Attebery, Timothy W; Newton, F Carter

    2004-12-01

    Technology advances in multislice detector computed tomography (MSCT) cardiac scanning, specifically in the application of intravenous injected contrast coronary angiography with EKG gating have led to the availability of this procedure in every day outpatient cardiac medicine. The aim of this study is to test the head to head direct coronary angiography with MSCT coronary angiography in clinical situations where cardiac cath is traditionally utilized for management decisions. We limited our analysis to vessels felt to be 1.5 mm or greater in diameter, recognizing diagnostic accuracy and medical importance of smaller vessels is low. All 50 patients (52% men, 48% women age range 34-78) were studied because of the clinical suspicion of obstructive coronary atherosclerosis. Blinded experts in direct and in MSCT independently read the studies and resolved disparities by a subsequent discussion. Standard protocols for direct and for MSCT angiography were used including use of IV and oral beta blockade to keep the heart rate at or below 60 beats per minute. 392 vessels were evaluated. MSCT provided images of sufficient technical quality to permit diagnosis in 98% (49/50) of cases. MSCT was 96% accurate in identifying patients as having either no disease, single vessel disease, or multiple vessel disease. For all vessels, MSCT identification of stenotic lesions of >50% were as follows: sensitivity 87%, specificity 97%, positive predictive value 80%, and negative predictive value 98%. Pearson correlation results between direct catheter and MSCT for absolute stenotic percentages were left main (0.92 p study.

  20. Safety and efficacy of dual-axis rotational coronary angiography vs. standard coronary angiography.

    Science.gov (United States)

    Klein, Andrew J; Garcia, Joel A; Hudson, Paul A; Kim, Michael S; Messenger, John C; Casserly, Ivan P; Wink, Onno; Hattler, Brack; Tsai, Thomas T; Chen, S Y James; Hansgen, Adam; Carroll, John D

    2011-05-01

    To determine the safety and efficacy of dual-axis rotational coronary angiography (DARCA) by directly comparing it to standard coronary angiography (SA). Standard coronary angiography (SA) requires numerous fixed static images of the coronary tree and has multiple well-documented limitations. Dual-axis rotational coronary angiography (DARCA) is a new rotational acquisition technique that entails simultaneous LAO/RAO and cranial/caudal gantry movement. This technological advancement obtains numerous unique images of the left or right coronary tree with a single coronary injection. We sought to assess the safety and efficacy of DARCA as well as determine DARCA's adequacy for CAD screening and assessment. Thirty patients underwent SA following by DARCA. Contrast volume, radiation dose (DAP) and procedural time were recorded for each method to assess safety. For DARCA acquisitions, blood pressure (BP), heart rate (HR), symptoms and any arrhythmias were recorded. All angiograms were reviewed for CAD screening adequacy by two independent invasive cardiologists. Compared to SA, use of DARCA was associated with a 51% reduction in contrast, 35% less radiation exposure, and 18% shorter procedural time. Both independent reviewers noted DARCA to be at least equivalent to SA with respect to the ability to screen for CAD. DARCA represents a new angiographic technique which is equivalent in terms of image quality and is associated with less contrast use, radiation exposure, and procedural time than SA. Copyright © 2011 Wiley-Liss, Inc.

  1. Adjoint current-based approaches to prostate brachytherapy optimization

    International Nuclear Information System (INIS)

    Roberts, J. A.; Henderson, D. L.

    2009-01-01

    This paper builds on previous work done at the Univ. of Wisconsin - Madison to employ the adjoint concept of nuclear reactor physics in the so-called greedy heuristic of brachytherapy optimization. Whereas that previous work focused on the adjoint flux, i.e. the importance, this work has included use of the adjoint current to increase the amount of information available in optimizing. Two current-based approaches were developed for 2-D problems, and each was compared to the most recent form of the flux-based methodology. The first method aimed to take a treatment plan from the flux-based greedy heuristic and adjust via application of the current-displacement, or a vector displacement based on a combination of tissue (adjoint) and seed (forward) currents acting as forces on a seed. This method showed promise in improving key urethral and rectal dosimetric quantities. The second method uses the normed current-displacement as the greedy criterion such that seeds are placed in regions of least force. This method, coupled with the dose-update scheme, generated treatment plans with better target irradiation and sparing of the urethra and normal tissues than the flux-based approach. Tables of these parameters are given for both approaches. In summary, these preliminary results indicate adjoint current methods are useful in optimization and further work in 3-D should be performed. (authors)

  2. Surrogate based approaches to parameter inference in ocean models

    KAUST Repository

    Knio, Omar

    2016-01-06

    This talk discusses the inference of physical parameters using model surrogates. Attention is focused on the use of sampling schemes to build suitable representations of the dependence of the model response on uncertain input data. Non-intrusive spectral projections and regularized regressions are used for this purpose. A Bayesian inference formalism is then applied to update the uncertain inputs based on available measurements or observations. To perform the update, we consider two alternative approaches, based on the application of Markov Chain Monte Carlo methods or of adjoint-based optimization techniques. We outline the implementation of these techniques to infer dependence of wind drag, bottom drag, and internal mixing coefficients.

  3. Non-contrast-enhanced peripheral angiography using a sliding interleaved cylinder acquisition.

    Science.gov (United States)

    Kwon, Kie Tae; Kerr, Adam B; Wu, Holden H; Hu, Bob S; Brittain, Jean H; Nishimura, Dwight G

    2015-09-01

    To develop a new sequence for non-contrast-enhanced peripheral angiography using a sliding interleaved cylinder (SLINCYL) acquisition. A venous saturation pulse was incorporated into a three-dimensional magnetization-prepared balanced steady-state free precession sequence for non-contrast-enhanced peripheral angiography to improve artery-vein contrast. The SLINCYL acquisition, which consists of a series of overlapped thin slabs for volumetric coverage similar to the original sliding interleaved ky (SLINKY) acquisition, was used to evenly distribute the venous-suppression effects over the field of view. In addition, the thin-slab-scan nature of SLINCYL and the centric-ordered sampling geometry of its readout trajectory were exploited to implement efficient fluid-suppression and parallel imaging schemes. The sequence was tested in healthy subjects and a patient. Compared to a multiple overlapped thin slab acquisition, both SLINKY and SLINCYL suppressed the venetian blind artifacts and provided similar artery-vein contrast. However, SLINCYL achieved this with shorter scan times and less noticeable artifacts from k-space amplitude modulation than SLINKY. The fluid-suppression and parallel imaging schemes were also validated. A patient study using the SLINCYL-based sequence well identified stenoses at the superficial femoral arteries, which were also confirmed with digital subtraction angiography. Non-contrast-enhanced angiography using SLINCYL can provide angiograms with improved artery-vein contrast in the lower extremities. © 2014 Wiley Periodicals, Inc.

  4. Problems and Projects Based Approach For Analog Electronic Circuits' Course

    Directory of Open Access Journals (Sweden)

    Mustapha Rafaf

    2009-04-01

    Full Text Available New educational methods and approaches are recently introduced and implemented at several North American and European universities using Problems and Projects Based Approach (PPBA. The PPBA employs a teaching technique based mostly on competences/skills rather than only on knowledge. This method has been implemented and proven by several pedagogical instructors and authors at several educational institutions. This approach is used at different disciplines such as medicine, biology, engineering and many others. It has the advantage to improve the student's skills and the knowledge retention rate, and reflects the 21st century industrial/company needs and demands. Before implementing this approach to a course, a good resources preparation and planning is needed upfront by the responsible or instructor of the course to achieve the course and students related objectives. This paper presents the preparation, the generated documentation and the implementation of a pilot project utilizing PPBA education for a second year undergraduate electronic course over a complete semester, and for two different class groups (morning and evening groups. The outcome of this project (achieved goals, observed difficulties and lessons learned is presented based on different tools such as students 'in class' communication and feedback, different course evaluation forms and the professor/instructor feedback. Resources, challenges, difficulties and recommendations are also assessed and presented. The impact, the effect and the results (during and at the end of the academic fall session of the PPBA on students and instructor are discussed, validated, managed and communicated to help other instructor in taking appropriate approach decisions with respect to this new educational approach compared to the classical one.

  5. 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.)

  6. Practice-Based Interdisciplinary Approach and Environmental Research

    Directory of Open Access Journals (Sweden)

    Ranjan Kumar Datta

    2017-03-01

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

  7. Evidence-based approach to harmonised reference intervals.

    Science.gov (United States)

    Koerbin, Gus; Sikaris, Ken Andrew; Jones, Graham Ross Dallas; Ryan, Julie; Reed, Maxine; Tate, Jill

    2014-05-15

    Although we are in the era of evidence-based medicine, there is still a substantial gap between theory and current practice with the application of reference intervals as decision making tools. Different laboratories may have different reference intervals for the same tests using the same analytical methods and platforms. These differences have the potential to confuse physicians making the assessment and monitoring of patients more difficult by providing discordant information. This paper attempts to demonstrate how to use evidence-based approach for harmonising reference intervals. In order to consider harmonisation we must first have an appreciation of the various factors that influence the determination of that reference interval such as the choice of individuals within the population studied, biological variability of the analyte studied, partitioning, sample collection, analytical aspects such as bias and statistical models. An a priori approach for determining reference intervals, whilst recommended, may be beyond the scope of most laboratories and consideration should be given to the use of a validated indirect a posteriori approach. Regardless of method used, the continuing application of an evidence-based approach in harmonised reference intervals to meet the quality expectations of physicians should be pursued. © 2013.

  8. Searching for adaptive traits in genetic resources - phenology based approach

    Science.gov (United States)

    Bari, Abdallah

    2015-04-01

    Searching for adaptive traits in genetic resources - phenology based approach Abdallah Bari, Kenneth Street, Eddy De Pauw, Jalal Eddin Omari, and Chandra M. Biradar International Center for Agricultural Research in the Dry Areas, Rabat Institutes, Rabat, Morocco Phenology is an important plant trait not only for assessing and forecasting food production but also for searching in genebanks for adaptive traits. Among the phenological parameters we have been considering to search for such adaptive and rare traits are the onset (sowing period) and the seasonality (growing period). Currently an application is being developed as part of the focused identification of germplasm strategy (FIGS) approach to use climatic data in order to identify crop growing seasons and characterize them in terms of onset and duration. These approximations of growing period characteristics can then be used to estimate flowering and maturity dates for dryland crops, such as wheat, barley, faba bean, lentils and chickpea, and assess, among others, phenology-related traits such as days to heading [dhe] and grain filling period [gfp]. The approach followed here is based on first calculating long term average daily temperatures by fitting a curve to the monthly data over days from beginning of the year. Prior to the identification of these phenological stages the onset is extracted first from onset integer raster GIS layers developed based on a model of the growing period that considers both moisture and temperature limitations. The paper presents some examples of real applications of the approach to search for rare and adaptive traits.

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

    Directory of Open Access Journals (Sweden)

    Junda Zhu

    2013-01-01

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

  10. Quantitative angiography methods for bifurcation lesions

    DEFF Research Database (Denmark)

    Collet, Carlos; Onuma, Yoshinobu; Cavalcante, Rafael

    2017-01-01

    Bifurcation lesions represent one of the most challenging lesion subsets in interventional cardiology. The European Bifurcation Club (EBC) is an academic consortium whose goal has been to assess and recommend the appropriate strategies to manage bifurcation lesions. The quantitative coronary...... angiography (QCA) methods for the evaluation of bifurcation lesions have been subject to extensive research. Single-vessel QCA has been shown to be inaccurate for the assessment of bifurcation lesion dimensions. For this reason, dedicated bifurcation software has been developed and validated. These software...

  11. Prostaglandin E1 in hand angiography

    Energy Technology Data Exchange (ETDEWEB)

    Levy, J.M.; Joseph, R.B.; Bodell, L.S.; Nykamp, P.W.; Hessel, S.J.

    1983-11-01

    Prostaglandin E1 (PG1) is a rapid, potent vasodilator which, when infused into the arterial system in low doses by bolus injection, has no significant systemic effects and has a relatively long duration of action. Sixty-three hand angiograms were done on 55 patients, comparing PGE1 to tolazoline and to angiograms done with no vasodilation. There was no significant difference between PGE1 and tolazoline in digital artery opacification; however, venous opacification was very significantly better with PGE1. PGE1 should be a drug of choice in hand angiography.

  12. Prostaglandin E1 in hand angiography

    International Nuclear Information System (INIS)

    Levy, J.M.; Joseph, R.B.; Bodell, L.S.; Nykamp, P.W.; Hessel, S.J.

    1983-01-01

    Prostaglandin E1 (PG1) is a rapid, potent vasodilator which, when infused into the arterial system in low doses by bolus injection, has no significant systemic effects and has a relatively long duration of action. Sixty-three hand angiograms were done on 55 patients, comparing PGE1 to tolazoline and to angiograms done with no vasodilation. There was no significant difference between PGE1 and tolazoline in digital artery opacification; however, venous opacification was very significantly better with PGE1. PGE1 should be a drug of choice in hand angiography

  13. 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.

  14. Integral diagnosis of coronary atherosclerosis by coronary multidetector computed tomography and by invasive coronary angiography

    International Nuclear Information System (INIS)

    Llerena Rojas, Luis Roberto; Llerena Rojas, Lorenzo D; Mendoza Rodriguez, Vladimir

    2013-01-01

    Coronary angiography by multidetector computed tomography (CMDCT) visualizes the wall and lumen of coronary arteries. Invasive coronary angiography (INVCA) only visualizes the arterial lumen but with better resolution

  15. Phishing Detection: Analysis of Visual Similarity Based Approaches

    Directory of Open Access Journals (Sweden)

    Ankit Kumar Jain

    2017-01-01

    Full Text Available Phishing is one of the major problems faced by cyber-world and leads to financial losses for both industries and individuals. Detection of phishing attack with high accuracy has always been a challenging issue. At present, visual similarities based techniques are very useful for detecting phishing websites efficiently. Phishing website looks very similar in appearance to its corresponding legitimate website to deceive users into believing that they are browsing the correct website. Visual similarity based phishing detection techniques utilise the feature set like text content, text format, HTML tags, Cascading Style Sheet (CSS, image, and so forth, to make the decision. These approaches compare the suspicious website with the corresponding legitimate website by using various features and if the similarity is greater than the predefined threshold value then it is declared phishing. This paper presents a comprehensive analysis of phishing attacks, their exploitation, some of the recent visual similarity based approaches for phishing detection, and its comparative study. Our survey provides a better understanding of the problem, current solution space, and scope of future research to deal with phishing attacks efficiently using visual similarity based approaches.

  16. Particle filter-based prognostic approach for railway track geometry

    Science.gov (United States)

    Mishra, Madhav; Odelius, Johan; Thaduri, Adithya; Nissen, Arne; Rantatalo, Matti

    2017-11-01

    Track degradation of ballasted railway track systems has to be measured on a regular basis, and these tracks must be maintained by tamping. Tamping aims to restore the geometry to its original shape to ensure an efficient, comfortable and safe transportation system. To minimize the disturbance introduced by tamping, this action has to be planned in advance. Track degradation forecasts derived from regression methods are used to predict when the standard deviation of a specific track section will exceed a predefined maintenance or safety limit. This paper proposes a particle filter-based prognostic approach for railway track degradation; this approach is demonstrated by examining different railway switches. The standard deviation of the longitudinal track degradation is studied, and forecasts of the maintenance limit intersection are derived. The particle filter-based prognostic results are compared with the standard regression method results for four railway switches, and the particle filter method shows similar or better result for the four cases. For longer prediction times, the error of the proposed method is equal to or smaller than that of the regression method. The main advantage of the particle filter-based prognostic approach is its ability to generate a probabilistic result based on input parameters with uncertainties. The distributions of the input parameters propagate through the filter, and the remaining useful life is presented using a particle distribution.

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

    International Nuclear Information System (INIS)

    Hyare, Harpreet; Desigan, Sharmini; Nicholl, Helen; Guiney, Michael J.; Brookes, Jocelyn A.; Lees, William R.

    2006-01-01

    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

  18. Utility of 16-multidetector CT angiography in the preoperative ...

    African Journals Online (AJOL)

    shanker

    calyces and ureters were assessed with delayed excretory phase images. On a 3D workstation, images were ... tional imaging techniques that included conventional angiography for the vascular anatomy and ..... tor CT angiography for evaluating the renal vascular anatomy and possible variations: a pictorial essay. Korean ...

  19. Quantification of fluorescence angiography in a porcine model

    DEFF Research Database (Denmark)

    Nerup, Nikolaj; Andersen, Helene Schou; Ambrus, Rikard

    2017-01-01

    PURPOSE: There is no consensus on how to quantify indocyanine green (ICG) fluorescence angiography. The aim of the present study was to establish and gather validity evidence for a method of quantifying fluorescence angiography, to assess organ perfusion. METHODS: Laparotomy was performed on seven...

  20. Gallbladder visualization on CT shortly after angiography with ioxaglate

    International Nuclear Information System (INIS)

    Tajima, H.; Kaizu, T.; Ichikawa, T.; Kumazaki, T.

    1994-01-01

    Thirty-five patients underwent CT examination 15 to 30 min after abdominal angiography with ioxaglate. The gallbladder was visualized in 12 patients in the absence of clinical evidence of renal impairment. Gallbladder opacification on CT examinations shortly after angiography shows that the hepatobiliary tract is important in the excretion of ioxaglate. (orig.)

  1. MR-angiography: the role of contrast agents

    Energy Technology Data Exchange (ETDEWEB)

    Goyen, Mathias; Ruehm, Stefan G.; Debatin, Joerg F. E-mail: debatin@uni-essen.de

    2000-06-01

    Contrast-enhanced 3D MR angiography (MRA) permits comprehensive assessment of the supraaortic arteries as well as the arterial system in the chest, abdomen and lower extremities. 3D MRA combines intravenous injection of a non-nephrotoxic, paramagnetic, extracellular contrast agent that increases the signal intensity of blood by shortening its T1 value with the acquisition of a fast 3D data set. High contrast between the vascular lumen and surrounding tissues, inherent three-dimensionality and the ability to collect image data in the chest and abdomen under apnea conditions all contribute to excellent image quality. This review provides clinical applications of 3D MRA in the chest, abdomen and lower extremities based upon the available literature and several clinical examples.

  2. Introduction to the principles of Digital Subtraction Angiography (DSA)

    International Nuclear Information System (INIS)

    Kaplanis, P.

    1997-01-01

    Medical applications of advanced technology have rapidly become more sophisticated and more widespread. The field of diagnostic imaging is by no means an exception. There has been a number of breathtaking developments in the field of medical imaging in recent years. Today higher quality, greater clarity and more minute precision are considered not advantages but necessities. Hence new developments are concentrated in the data acquisition and image processing based on the microprocessor controlled modules interfaced with state of the art radiological imaging equipment. One such development is the subtraction of x-rays vis a computer for better visualization of blood vessels, cavities of the heart and of the coronary and pulmonary vascular system. This procedure is termed Digital Subtraction Angiography (DSA). (author)

  3. 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...

  4. 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.

  5. [Managing constipation in the elderly: an evidence-based approach].

    Science.gov (United States)

    Lin, Yi-Chen; Yen, Miaofen; Chen, Ching-Huey

    2010-08-01

    Constipation is a common problem afflicting the elderly. When elderly patients complain of constipation to their healthcare providers, they are typically prescribed laxatives rather than given a clinical examination to explore the specific causes. This approach not only does not resolve the long-term problem of constipation, but may also lead to further complications (e.g., constipation alternating with diarrhea, abdominal distention, poor appetite, and ileus). Effective management of constipation in the elderly should in many cases be tailored to the symptoms and conditions of individual patients rather than simply applying evidence-based treatment. There is a lack of consistency amongst specialists on how best to deal with the problem of constipation. The aim of this article was to explore evidence-based management approaches to constipation in the elderly. A definition of constipation is given and relevant causes are first given. Pharmacological and non-pharmacological treatment approaches are then introduced with regard to effective approaches to conducting physical examinations, assessing patient medical history, and performing laboratory tests. In addition, this article also developed a constipation protocol as a reference tool in the clinical management of constipation in the elderly. The authors hope results can help reduce the problem of constipation in the elderly population.

  6. An Iterative Load Disaggregation Approach Based on Appliance Consumption Pattern

    Directory of Open Access Journals (Sweden)

    Huijuan Wang

    2018-04-01

    Full Text Available Non-intrusive load monitoring (NILM, monitoring single-appliance consumption level by decomposing the aggregated energy consumption, is a novel and economic technology that is beneficial to energy utilities and energy demand management strategies development. Hardware costs of high-frequency sampling and algorithm’s computational complexity hampered NILM large-scale application. However, low sampling data shows poor performance in event detection when multiple appliances are simultaneously turned on. In this paper, we contribute an iterative disaggregation approach that is based on appliance consumption pattern (ILDACP. Our approach combined Fuzzy C-means clustering algorithm, which provide an initial appliance operating status, and sub-sequence searching Dynamic Time Warping, which retrieves single energy consumption based on the typical power consumption pattern. Results show that the proposed approach is effective to accurately disaggregate power consumption, and is suitable for the situation where different appliances are simultaneously operated. Also, the approach has lower computational complexity than Hidden Markov Model method and it is easy to implement in the household without installing special equipment.

  7. Correlation of angiography and MR imaging in cerebral vasculitis

    International Nuclear Information System (INIS)

    Cloft, H.J.; Phillips, C.D.; Dix, J.E.; McNulty, B.C.; Kallmes, D.F.; Zagardo, M.T.

    1999-01-01

    Purpose: MR imaging and cerebral angiography were correlated in patients with primary angiitis of the central nervous system (PACNS) to assess the relative roles of these imaging modalities in the diagnosis. Material and Methods: In 9 patients, MR imaging and angiography were compared with regard to the relative involvement of each major vascular territory. Vascular territories assessed were the anterior, middle, and posterior cerebral arteries, and the posterior fossa. Results: All patients had angiographic findings consistent with vasculitis in multiple vascular territories. MR findings ranged from normal to diffusely abnormal. One patient had a completely normal MR investigation. Of 50 territories affected by vasculitis on angiography, 17 (34%) were normal on MR. Conclusion: Relative to cerebral angiography, MR imaging is a poor indicator of the presence or absence of PACNS. Angiography is indicated when clinical suspicion of PACNS is strong, regardless of the findings on MR. (orig.)

  8. Comparison between angiography and CT scan in the urologic field

    International Nuclear Information System (INIS)

    Fujioka, Toshio; Takao, Masaya; Odajima, Kunio; Nakamura, Hiroshi

    1988-01-01

    Seventy-five consecutive patients with urological diseases were examined preoperatively by means of computerized tomography and renal angiography. Classification of the diseases were 53 renal diseases which included renal cell carcinoma, sarcoma, cyst, renal bleeding, arteriovenous fistula, trauma, hydronephrosis and tuberculosis, 11 vesical diseases which included bladder tumor and endometriosis, 9 adrenal diseases which included primary aldosteronism, Cushing syndrome, pheochromocytoma, and metastatic tumor, and 1 case of intra-abdominal testes. For renal diseases, both angiography and CT were useful imaging tools. For vesical diseases, CT was a more useful imaging method but, for adrenal diseases, angiography was superior to CT. CT offers certain advantages over conventional techniques but, in the near future, it may be replaced by MRI. On the contrary, angiography will remain popular for a long time, because angiography is the only way to show which vessels feed organs. (author)

  9. Magnetic resonance angiography in suspected cerebral vasculitis

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-06-01

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

  10. Magnetic resonance angiography in suspected cerebral vasculitis

    International Nuclear Information System (INIS)

    Demaerel, Philippe; De Ruyter, Nele; Wilms, Guido; Maes, Frederik; Velghe, Beatrijs

    2004-01-01

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

  11. Coronary CT angiography in symptomatic patients

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-02-01

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

  12. Magnetic resonance angiography of the cerebral vessels

    International Nuclear Information System (INIS)

    Peters, P.E.; Bongartz, G.; Drews, C.

    1990-01-01

    In a prospective study involving 52 patients, magnetic resonance angiography (MRA) was compared with arterial digital subtraction angiography (IA-DSA). MRA was performed within three days of the IA-DSA. It was carried out without knowledge of the findings on IA-DSA. Of 38 stenoses of the carotid arteries or their branches, demonstrated by IA-DSA, 33 could be seen on MRA; in four cases the stenosis was outside the imaging area of the coil. Sixteen out of 17 carotid occlusions were diagnosed by MRA. There was one false positive. In the vertebral artery territory, eleven out of 13 stenoses and three out of four occlusions were diagnosed by MRA. In evaluating the degree of stenosis, there was agreement in only 16 out of 33 cases. MRA over-estimated the severity of stenoses in 15 cases and underestimated it in two. MRA is a new non-invasive method in the diagnosis of cerebro-vascular disease which must be evaluated by further studies. (orig.) [de

  13. Contrast agent choice for intravenous coronary angiography

    International Nuclear Information System (INIS)

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

    1989-01-01

    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 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 contains a 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

  14. Spinor-based approach on wave processes in optical fiber

    Science.gov (United States)

    Bagmanov, Valeriy Kh.; Sultanov, Albert Kh.

    2017-04-01

    In this paper we introduce a novel approach for analysis of the information transmission process in mode-divisionmultiplexed (MDM) optical fiber communications. This approach is based on the representation of Maxwell's equations in the form of quantum-mechanical Schrödinger and Dirac equations. This representation allows application of the well-developed quantum electrodynamics formalism for the case of classical EM fields and reveals key properties of the optical fiber mode distribution in MDM systems following from the total angular momentum conservation law. We demonstrate the need of using coupled mode compositions instead of separate eigenmodes for realization of MDM communications based on angular momentum transfer. Such coupled modal compositions obey the law of total angular momentum conservation within spatial transformation and allow information transmission.

  15. 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.

  16. Deep-Learning-Based Approach for Prediction of Algal Blooms

    Directory of Open Access Journals (Sweden)

    Feng Zhang

    2016-10-01

    Full Text Available Algal blooms have recently become a critical global environmental concern which might put economic development and sustainability at risk. However, the accurate prediction of algal blooms remains a challenging scientific problem. In this study, a novel prediction approach for algal blooms based on deep learning is presented—a powerful tool to represent and predict highly dynamic and complex phenomena. The proposed approach constructs a five-layered model to extract detailed relationships between the density of phytoplankton cells and various environmental parameters. The algal blooms can be predicted by the phytoplankton density obtained from the output layer. A case study is conducted in coastal waters of East China using both our model and a traditional back-propagation neural network for comparison. The results show that the deep-learning-based model yields better generalization and greater accuracy in predicting algal blooms than a traditional shallow neural network does.

  17. Earthquake insurance pricing: a risk-based approach.

    Science.gov (United States)

    Lin, Jeng-Hsiang

    2018-04-01

    Flat earthquake premiums are 'uniformly' set for a variety of buildings in many countries, neglecting the fact that the risk of damage to buildings by earthquakes is based on a wide range of factors. How these factors influence the insurance premiums is worth being studied further. Proposed herein is a risk-based approach to estimate the earthquake insurance rates of buildings. Examples of application of the approach to buildings located in Taipei city of Taiwan were examined. Then, the earthquake insurance rates for the buildings investigated were calculated and tabulated. To fulfil insurance rating, the buildings were classified into 15 model building types according to their construction materials and building height. Seismic design levels were also considered in insurance rating in response to the effect of seismic zone and construction years of buildings. This paper may be of interest to insurers, actuaries, and private and public sectors of insurance. © 2018 The Author(s). Disasters © Overseas Development Institute, 2018.

  18. Risk-Based Approach to Developing National Residue Sampling Plan

    OpenAIRE

    Scientific Committee of the Food Safety Authority of Ireland

    2014-01-01

    A ranking system for veterinary medicinal products and medicated feed additives has been developed as a tool to be applied in a risk-based approach to the residue testing programme for foods of animal origin in the National Residue Control Plan. In the context of food sampling and residue testing for the National Residue Control Plan, there is firstly, the risk to human health from residues of chemical substances in food and secondly, the issue of non-compliance with regulations relating ...

  19. Subcutaneous injection technique: an evidence-based approach.

    Science.gov (United States)

    Ogston-Tuck, Sherri

    2014-09-23

    Injections are routinely administered by nurses in acute care settings and in the community. Nurses require a thorough understanding of anatomy and physiology, pharmacological principles and equipment, and potential risks to the patient of injections. Nurses should also take an active approach to patient assessment before injecting medicines. This article, the first of two, provides an evidence-based review of injection administration, with particular reference to subcutaneous injections, and suggests a framework for best practice.

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

    Directory of Open Access Journals (Sweden)

    Pilotti Pablo

    2015-09-01

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

  1. 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.

  2. The utility of CT angiography in planning perineal flap reconstruction following radical pelvic surgery.

    Science.gov (United States)

    Rosich-Medina, A; Ariyaratnam, J; Koo, B; Turner, W H; Fearnhead, N S; Durrani, A; Davies, R J

    2012-01-01

    Closure of the perineum following radical excision of pelvic tumours can prove to be a complex surgical problem. A number of pedicled flaps have been used for perineal reconstruction in order to reduce post-operative complications such as infection and abscess formation. The aim of this case series was to analyse the use of pre-operative computer tomography (CT) angiography to guide flap selection for perineal reconstruction following radical excision of pelvic tumours. We conducted a retrospective review to identify all patients who underwent CT angiography prior to radical excision of pelvic tumours and planned flap reconstruction over an 18 month period. Six patients were identified and are presented in this case series. Patients' medical records, histology reports, pre-operative investigations and CT angiograms, complications and follow-up were reviewed. The mean patient age was 58.3 years, with a male to female ratio of 1:2. Four out of six patients (66.6%) underwent pre-operative radiotherapy. The deep inferior epigastric arteries (DIEA) were visualised in all six cases (100%) and the pre-operative CT angiography helped guide flap choice in all cases (100%). In one case, narrowing of the DIEA vessels was noted precluding the use of a DIEA-based flap. One patient had a minor superficial wound dehiscence. Pre-operative CT angiography allows accurate visualisation of the DIEA system including perforator vessels. CT angiography is a useful tool, providing the surgical team with significant additional information to aid pre-operative planning and optimise reconstructive choice and outcome. Copyright © 2012 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  3. Influencing factors for condition-based maintenance in railway tracks using knowledge-based approach

    NARCIS (Netherlands)

    Jamshidi, A.; Hajizadeh, S.; Naeimi, M.; Nunez Vicencio, Alfredo; Li, Z.

    2017-01-01

    In this paper, we present a condition-based maintenance decision method using
    knowledge-based approach for rail surface defects. A railway track may contain a considerable number of surface defects which influence track maintenance decisions. The proposed method is based on two sets of

  4. A structural informatics approach to mine kinase knowledge bases.

    Science.gov (United States)

    Brooijmans, Natasja; Mobilio, Dominick; Walker, Gary; Nilakantan, Ramaswamy; Denny, Rajiah A; Feyfant, Eric; Diller, David; Bikker, Jack; Humblet, Christine

    2010-03-01

    In this paper, we describe a combination of structural informatics approaches developed to mine data extracted from existing structure knowledge bases (Protein Data Bank and the GVK database) with a focus on kinase ATP-binding site data. In contrast to existing systems that retrieve and analyze protein structures, our techniques are centered on a database of ligand-bound geometries in relation to residues lining the binding site and transparent access to ligand-based SAR data. We illustrate the systems in the context of the Abelson kinase and related inhibitor structures. 2009 Elsevier Ltd. All rights reserved.

  5. Toward a Mechanism-Based Approach to Pain Diagnosis.

    Science.gov (United States)

    Vardeh, Daniel; Mannion, Richard J; Woolf, Clifford J

    2016-09-01

    The past few decades have witnessed a huge leap forward in our understanding of the mechanistic underpinnings of pain, in normal states where it helps protect from injury, and also in pathological states where pain evolves from a symptom reflecting tissue injury to become the disease itself. However, despite these scientific advances, chronic pain remains extremely challenging to manage clinically. Although the number of potential treatment targets has grown substantially and a strong case has been made for a mechanism-based and individualized approach to pain therapy, arguably clinicians are not much more advanced now than 20 years ago, in their capacity to either diagnose or effectively treat their patients. The gulf between pain research and pain management is as wide as ever. We are still currently unable to apply an evidence-based approach to chronic pain management that reflects mechanistic understanding, and instead, clinical practice remains an empirical and often unsatisfactory journey for patients, whose individual response to treatment cannot be predicted. In this article we take a common and difficult to treat pain condition, chronic low back pain, and use its presentation in clinical practice as a framework to highlight what is known about pathophysiological pain mechanisms and how we could potentially detect these to drive rational treatment choice. We discuss how present methods of assessment and management still fall well short, however, of any mechanism-based or precision medicine approach. Nevertheless, substantial improvements in chronic pain management could be possible if a more strategic and coordinated approach were to evolve, one designed to identify the specific mechanisms driving the presenting pain phenotype. We present an analysis of such an approach, highlighting the major problems in identifying mechanisms in patients, and develop a framework for a pain diagnostic ladder that may prove useful in the future, consisting of successive

  6. A machine vision based approach for timber knots detection

    Science.gov (United States)

    Hittawe, Mohamad Mazen; Sidibé, Désiré; Mériaudeau, Fabrice

    2015-04-01

    Wood singularities detection is a primary step in wood grading enhancement. Our approach is purely machine vision based. The main objective is to compute physical properties like density, modulus of elasticity (MOE) and modulus of rupture (MOR) given wood surface images. Knots are one of the main singularities which directly affect the wood strength. Hence, our target is to detect knots and classify them into transverse and non-transverse ones. Then the Knots Depth Ratio (KDR) is computed based on all found transverse knots. Afterwards, KDR is used for the wood mechanical model improvement. Our technique is based on colour image analysis where the knots are detected by means of contrast intensity transformation and morphological operations. Then KDR computations are based on transverse knots and clear wood densities. Finally, MOE and MOR are computed using KDR images. The accuracy of number of knots found, their locations, MOE and MOR has been validated using a dataset of 252 images. In our dataset, these values were manually calculated. To the best of our knowledge our approach is the first purely machine vision based method to compute KDR, MOE and MOR.

  7. 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.

  8. 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. 

  9. 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.

  10. Conceptual design of jewellery: a space-based aesthetics approach

    Directory of Open Access Journals (Sweden)

    Tzintzi Vaia

    2017-01-01

    Full Text Available Conceptual design is a field that offers various aesthetic approaches to generation of nature-based product design concepts. Essentially, Conceptual Product Design (CPD uses similarities based on the geometrical forms and functionalities. Furthermore, the CAD-based freehand sketch is a primary conceptual tool in the early stages of the design process. The proposed Conceptual Product Design concept is dealing with jewelleries that are inspired from space. Specifically, a number of galaxy features, such as galaxy shapes, wormholes and graphical representation of planet magnetic field are used as inspirations. Those space-based design ideas at a conceptual level can lead to further opportunities for research and economic success of the jewellery industry. A number of illustrative case studies are presented and new opportunities can be derived for economic success.

  11. A clinical approach to the diagnosis of retinal vasculitis.

    Science.gov (United States)

    El-Asrar, Ahmed M Abu; Herbort, Carl P; Tabbara, Khalid F

    2010-04-01

    Retinal vasculitis is a sight-threatening inflammatory eye condition that involves the retinal vessels. Detection of retinal vasculitis is made clinically, and is confirmed with the help of fundus fluorescein angiography. Active vascular disease is characterized by exudates around retinal vessels resulting in white sheathing or cuffing of the affected vessels. In this review, a practical approach to the diagnosis of retinal vasculitis is discussed based on ophthalmoscopic and fundus fluorescein angiographic findings.

  12. 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.

  13. Coronary lesions quantification with dual-axis rotational coronary angiography.

    Science.gov (United States)

    Unzué Vallejo, Leire; Delcán Domínguez, Juan Luis; Alegría Barrero, Ana; Medina Peralta, Juan; Rodríguez Rodrigo, Francisco José; Rodríguez-López, Jose Luis

    2013-01-01

    Coronary angiography (CA) has been the gold standard technique for studying coronary artery disease. It is based on the analysis of bidimensional orthogonal projections that may not be optimal to estimate determinate coronary segments. Rotational angiography "Xperswing" (DARCA) is a new technique that allows the visualization of the coronary arteries from multiple views, with a single contrast injection. The aim of this study is to evaluate the coronary lesions quantification with DARCA. Quantitative coronary analysis of significant coronary stenosis (>50%) was performed. Every lesion was measured in two different projections: the "optimal projection", obtained by DARCA and defined by the operator as the one with a better lesion qualification, and the "standard projection", corresponding to the usual projection closer to the optimal one in obliquity and angulation. Measures were performed twice and by two independent operators. Intra- and inter-observer correlation was estimated by Kappa index and variables were compared with t Student test (SPSS 14.0). 205 lesions in 147 patients were analyzed. Kappa coefficient intra-observer was 0.80 and 0.86 respectively with an inter-observer correlation index of 0.72. Lesion length and maximal diameter of the vessel were significantly greater in the group of RA. In the segments analysis, calculated length was longer for the first diagonal branch, first marginal obtuse artery, middle circumflex, middle and distal RCA and posterior descending artery, with greater reference diameters for proximal LAD and distal RCA. There were no significant differences for coronary stenosis grade. RA XperSwing provides a better visualization of coronary arteries improving lesions characterization, with longer measured lesions length and greater vessel diameters, especially in coronary segments with more angulation. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Towards a mechanism-based approach to pain diagnosis

    Science.gov (United States)

    Vardeh, Daniel

    2016-01-01

    The last few decades have witnessed a huge leap forward in our understanding of the mechanistic underpinnings of pain, both in normal states where it helps protect from injury, and in pathological states where pain evolves from a symptom reflecting tissue injury to become the disease itself. However, despite these scientific advances, chronic pain remains extremely challenging to manage clinically. While the number of potential treatment targets has grown substantially and a strong case has been made for a mechanism-based and individualized approach to pain therapy, arguably clinicians are not much more advanced now than 20 years ago, in their capacity to either diagnose or effectively treat their patients. The gulf between pain research and pain management is as wide as ever. We are still currently unable to apply an evidence-based approach to chronic pain management that reflects mechanistic understanding, and instead, clinical practice remains an empirical and often unsatisfactory journey for patients, whose individual response to treatment cannot be predicted. Here we take a common and difficult to treat pain condition, chronic low back pain, and use its presentation in clinical practice as a framework to highlight what is known about pathophysiological pain mechanisms and how we could potentially detect these to drive rational treatment choice. We discuss how present methods of assessment and management still fall well short, however, of any mechanism-based or precision-medicine approach. Nevertheless, substantial improvements in chronic pain management could be possible if a more strategic and coordinated approach were to evolve, one designed to identify the specific mechanisms driving the presenting pain phenotype. We present an analysis of such an approach, highlighting the major problems in identifying mechanisms in patients, and develop a framework for a pain diagnostic ladder that may prove useful in the future, consisting of successive identification of

  15. Age- and sex-based resource utilisation and costs in patients with acute chest pain undergoing cardiac CT angiography. Pooled evidence from ROMICAT II and ACRIN-PA trials

    International Nuclear Information System (INIS)

    Bamberg, Fabian; Hoffmann, Udo; Mayrhofer, Thomas; Ferencik, Maros; Bittner, Daniel O.; Hallett, Travis R.; Janjua, Sumbal; Schlett, Christopher L.; Nagurney, John T.; Udelson, James E.; Truong, Quynh A.; Woodard, Pamela K.; Hollander, Judd E.; Litt, Harold

    2018-01-01

    To determine resource utilisation according to age and gender-specific subgroups in two large randomized diagnostic trials. We pooled patient-specific data from ACRIN-PA 4005 and ROMICAT II that enrolled subjects with acute chest pain at 14 US sites. Subjects were randomized between a standard work-up and a pathway utilizing cardiac computed tomography angiography (CCTA) and followed for the occurrence of acute coronary syndrome (ACS) and resource utilisation during index hospitalisation and 1-month follow-up. Study endpoints included diagnostic accuracy of CCTA for the detection of ACS as well as resource utilisation. Among 1240 patients who underwent CCTA, negative predictive value of CCTA to rule out ACS remained very high (≥99.4%). The proportion of patients undergoing additional diagnostic testing and cost increased with age for both sexes (p < 0.001), and was higher in men as compared to women older than 60 years (43.1% vs. 23.4% and $4559 ± 3382 vs. $3179 ± 2562, p < 0.01; respectively). Cost to rule out ACS was higher in men (p < 0.001) and significantly higher for patients older than 60 years ($2860-5935 in men, p < 0.001). CCTA strategy in patients with acute chest pain results in varying resource utilisation according to age and gender-specific subgroups, mandating improved selection for advanced imaging. (orig.)

  16. A probabilistic approach to the drag-based model

    Science.gov (United States)

    Napoletano, Gianluca; Forte, Roberta; Moro, Dario Del; Pietropaolo, Ermanno; Giovannelli, Luca; Berrilli, Francesco

    2018-02-01

    The forecast of the time of arrival (ToA) of a coronal mass ejection (CME) to Earth is of critical importance for our high-technology society and for any future manned exploration of the Solar System. As critical as the forecast accuracy is the knowledge of its precision, i.e. the error associated to the estimate. We propose a statistical approach for the computation of the ToA using the drag-based model by introducing the probability distributions, rather than exact values, as input parameters, thus allowing the evaluation of the uncertainty on the forecast. We test this approach using a set of CMEs whose transit times are known, and obtain extremely promising results: the average value of the absolute differences between measure and forecast is 9.1h, and half of these residuals are within the estimated errors. These results suggest that this approach deserves further investigation. We are working to realize a real-time implementation which ingests the outputs of automated CME tracking algorithms as inputs to create a database of events useful for a further validation of the 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. 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

  20. 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. © 2016 S. Karger AG, Basel.

  1. Architectural approaches for HL7-based health information systems implementation.

    Science.gov (United States)

    López, D M; Blobel, B

    2010-01-01

    Information systems integration is hard, especially when semantic and business process interoperability requirements need to be met. To succeed, a unified methodology, approaching different aspects of systems architecture such as business, information, computational, engineering and technology viewpoints, has to be considered. The paper contributes with an analysis and demonstration on how the HL7 standard set can support health information systems integration. Based on the Health Information Systems Development Framework (HIS-DF), common architectural models for HIS integration are analyzed. The framework is a standard-based, consistent, comprehensive, customizable, scalable methodology that supports the design of semantically interoperable health information systems and components. Three main architectural models for system integration are analyzed: the point to point interface, the messages server and the mediator models. Point to point interface and messages server models are completely supported by traditional HL7 version 2 and version 3 messaging. The HL7 v3 standard specification, combined with service-oriented, model-driven approaches provided by HIS-DF, makes the mediator model possible. The different integration scenarios are illustrated by describing a proof-of-concept implementation of an integrated public health surveillance system based on Enterprise Java Beans technology. Selecting the appropriate integration architecture is a fundamental issue of any software development project. HIS-DF provides a unique methodological approach guiding the development of healthcare integration projects. The mediator model - offered by the HIS-DF and supported in HL7 v3 artifacts - is the more promising one promoting the development of open, reusable, flexible, semantically interoperable, platform-independent, service-oriented and standard-based health information systems.

  2. Increased risk for complications following diagnostic cerebral angiography in older patients: Trends from the Nationwide Inpatient Sample (1999-2009).

    Science.gov (United States)

    Choudhri, Omar; Schoen, Matthew; Mantha, Aditya; Feroze, Abdullah; Ali, Rohaid; Lawton, Michael T; Do, Huy M

    2016-10-01

    The full utility of diagnostic cerebral angiography, an invasive cerebrovascular imaging technique, is currently debated. Our goal was to determine trends in diagnostic cerebral angiography utilization and associated complications from 1999 through 2009. The National Inpatient Sample (NIS) was used to identify patients who received primary cerebral angiography from 1999-2009 in the United States. We observed trends in discharge volume, total mean charge, and post-procedural complications for this population. Data was based on sample projections and analyzed using univariate and multivariate regression. There were a total of 424,105 discharges indicating primary cerebral angiography nationwide from 1999-2009. The majority of these cases (65%) were in patients older than 55years. Embolic stroke was the most frequent complication, particularly in the oldest age bracket, occurring in 16,304 patients. The risk for complications increased with age (p<0.0001) and with other underlying health conditions. Pulmonary, deep vein thrombosis, and renal associated comorbidities resulted in the greatest risk for developing post-procedural complications. Throughout the study period case volume for cerebral angiography remained constant while total charge per patient increased from $17,365 in 1999 to $45,339 in 2009 (p<0.001). While the overall complication rate for this invasive procedure is relatively low, the potential risk for embolic stroke in older patients is significant. It is worth considering less invasive diagnostic techniques for an older and at risk patient population. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Application of longitudinal magnification effect to magnification stereoscopic angiography. A new method of cerebral angiography

    International Nuclear Information System (INIS)

    Doi, K.; Rossmann, K.; Duda, E.E.

    1976-01-01

    A new method of stereoscopic cerebral angiography was developed which employs 2X radiographic magnification. In order to obtain the same depth perception in the object as with conventional contact stereoscopic angiography, one can make the x-ray exposures at two focal spot positions which are separated by only 1 inch, whereas the contact technique requires a separation of 4 inches. The smaller distance is possible because, with 2X magnification, the transverse detail in the object is magnified by a factor of two, but the longitudinal detail, which is related to the stereo effect, is magnified by a factor of four, due to the longitudinal magnification effect. The small focal spot separation results in advantages such as improved stereoscopic image detail, better image quality, and low radiation exposure to the patient

  4. Conventional renal angiography versus renal digital subtraction angiography (DSA) in the study of renovascular hypertension

    International Nuclear Information System (INIS)

    Essinger, A.; Morsier, B. de; Narbel, M.; Raimondi, S.

    1988-01-01

    A cost-benefit analysis comparing conventional renal angiography, IV and IA DSA and spot film cameras has been made in order to quantify the advantages and disadvantages of these techniques in screening for renal artery stenosis. DSA is the best modality of imaging, using very little films, easy to archive, with a spatial resolution inferior to conventional angiography but partially compensated by contrast resolution. The surface dose per image using a 512/512 matrix is two thirds less than a conventional film, giving thus an acceptable dose as long as technical personnel is well trained and thus the number of exposures is kept low. Spot film camera, due to its excellent spatial resolution, its low radiation dose and its low price, can also be used as a screening procedure but requires an arterial injection. DSA has furthermore the advantage of quantifying renal artery stenosis making future percutaneous transluminal angioplasty easier

  5. Combined use of intraarterial digital subtraction angiography with conventional retrograde brachial vertebral angiography

    International Nuclear Information System (INIS)

    Yamaguchi, Tatsuo; Ogawa, Toshihide; Inugami, Atsushi; Kawata, Yasushi; Shishido, Fumio; Uemura, Kazuo

    1985-01-01

    For 102 patients who had the examination of conventional bilaterally retrograde brachial vertebral angiography (retrograde VAG), intraarterial digital subtraction angiography (DSA) was successively performed to investigate steno-occlusive lesions of proximal vertebral and subclavian arteries. All the patients had no complication due to the DSA procedure. In 50% of 72 ischemic stroke cases, positive findings were found either in the origin of the vertebral artery or in the subclavian artery. Stenosis of more than 50% of the lumen of the vertebral artery were found in 14% of the cases at the origin of the right one and also in 14% in the left one. Occlusion of the vertebral artery was found in 4% in the left side only. In 30 cases with non-ischemic brain diseases, positive findings were noted in 10%. Intraarterial DSA combined with retrograde VAG was thought to be useful, especially in the examination for ischemic stroke. (author)

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

    International Nuclear Information System (INIS)

    Kandeel, A.Y.; Zimmerman, R.A.; Ohene-Frempong, K.

    1996-01-01

    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.)

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

    DEFF Research Database (Denmark)

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

    2012-01-01

    PURPOSE: Coronary computed tomography angiography (CTA) has proven to be useful for noninvasive examination in patients with intermediate risk of coronary artery disease. However, data addressing patients' views of this relatively new diagnostic modality are sparse. MATERIALS AND METHODS: For com......PURPOSE: Coronary computed tomography angiography (CTA) has proven to be useful for noninvasive examination in patients with intermediate risk of coronary artery disease. However, data addressing patients' views of this relatively new diagnostic modality are sparse. MATERIALS AND METHODS...... procedure. CONCLUSION: The large majority of patients preferred CTA over conventional CA. This choice was most likely the result of less physical discomfort, fewer minor bleeding complications, and a higher rate of early return to work after CTA when compared with CA....

  8. An Asset-Based Approach to Tribal Community Energy Planning

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, Rachael A. [Pratt Inst., Brooklyn, NY (United States). City and Regional Planning; Martino, Anthony [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Materials, Devices, and Energy Technologies; Begay, Sandra K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Materials, Devices, and Energy Technologies

    2016-08-01

    Community energy planning is a vital component of successful energy resource development and project implementation. Planning can help tribes develop a shared vision and strategies to accomplish their energy goals. This paper explores the benefits of an asset-based approach to tribal community energy planning. While a framework for community energy planning and federal funding already exists, some areas of difficulty in the planning cycle have been identified. This paper focuses on developing a planning framework that offsets those challenges. The asset-based framework described here takes inventory of a tribe’s capital assets, such as: land capital, human capital, financial capital, and political capital. Such an analysis evaluates how being rich in a specific type of capital can offer a tribe unique advantages in implementing their energy vision. Finally, a tribal case study demonstrates the practical application of an asset-based framework.

  9. 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.

  10. Utility of computed axial tomography angiography in anatomic evaluation of pediatric patients with congenital heart diseases

    International Nuclear Information System (INIS)

    Mosquera, Walter A; Reyes P, Rafael; Aguilera N, Favio M; Breton, Cesar A; Buitrago, Danuby A; Suarez J Ramiro; Castillo, Victor

    2007-01-01

    Although echocardiogram and cardiac catheterization are used as first option tools for congenital heart diseases diagnosis, computed tomography angiography is a minimally invasive exam that through two to three dimensional images in real time gives an adequate approach to patients having this type of pathologies that require a rapid and precise evaluation of its extra cardiac anatomy. Objective: describe the institutional experience from August 2005 to August 2006 in the use of angiography by tomography as a complementary diagnostic method in the evaluation of pediatric patients with congenital heart diseases. Method: serial descriptive study. 58 pediatric patients with clinical and echocardiographic diagnosis of congenital heart diseases were evaluated through the General Electric Multislice Light peed/16 scanner. Results: 58 patients with history of congenital heart disease were evaluated through CT angiography. Mean age was 2.4 ± 4.03 years. Twenty (33.8%) had diagnosis of pulmonary atresia, four (6.7%) had tricuspid atresia, eight (13.5%,) had double-outlet right ventricle, seven (11.8%) had tetralogy of Fallot, nine (15.2%) had alterations of the aortic arch, seven (11.8%) had coarctation of the aorta two (3.3%) had interrupted aortic arch, six (10.3%) had persistent ductus arteriosus, four (6.7%) had anomalous venous drainage and three (5.1 %) had transposition of the great arteries. High quality images that allowed assessing the precise vascular anatomy were obtained. Conclusions: computed tomography angiography turned out to be a useful tool in the diagnostic approach of congenital heart diseases, because it allowed a tridimensional anatomic reconstruction. New studies that may permit the assessment of sensitivity, specificity and concordance level of this technique with other invasive diagnostic methods available for the diagnosis of this type of diseases, are required

  11. New approach for risk based inspection of H2S based Process Plants

    International Nuclear Information System (INIS)

    Vinod, Gopika; Sharma, Pavan K.; Santosh, T.V.; Hari Prasad, M.; Vaze, K.K.

    2014-01-01

    Highlights: • Study looks into improving the consequence evaluation in risk based inspection. • Ways to revise the quantity factors used in qualitative approach. • New approach based on computational fluid dynamics along with probit mathematics. • Demonstrated this methodology along with a suitable case study for the said issue. - Abstract: Recent trend in risk informed and risk based approaches in life management issues have certainly put the focus on developing estimation methods for real risk. Idea of employing risk as an optimising measure for in-service inspection, termed as risk based inspection, was accepted in principle from late 80s. While applying risk based inspection, consequence of failure from each component needs to be assessed. Consequence evaluation in a Process Plant is a crucial task. It may be noted that, in general, the number of components to be considered for life management is very large and hence the consequence evaluation resulting from their failures (individually) is a laborious task. Screening of critical components is usually carried out using simplified qualitative approach, which primarily uses influence factors for categorisation. This necessitates logical formulation of influence factors and their ranges with a suitable technical basis for acceptance from regulators. This paper describes application of risk based inspection for H 2 S based Process Plant along with the approach devised for handling the influence factor related to the quantity of H 2 S released

  12. A dictionary-based approach for gene annotation.

    Science.gov (United States)

    Pachter, L; Batzoglou, S; Spitkovsky, V I; Banks, E; Lander, E S; Kleitman, D J; Berger, B

    1999-01-01

    This paper describes a fast and fully automated dictionary-based approach to gene annotation and exon prediction. Two dictionaries are constructed, one from the nonredundant protein OWL database and the other from the dbEST database. These dictionaries are used to obtain O (1) time lookups of tuples in the dictionaries (4 tuples for the OWL database and 11 tuples for the dbEST database). These tuples can be used to rapidly find the longest matches at every position in an input sequence to the database sequences. Such matches provide very useful information pertaining to locating common segments between exons, alternative splice sites, and frequency data of long tuples for statistical purposes. These dictionaries also provide the basis for both homology determination, and statistical approaches to exon prediction.

  13. 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

  14. 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.

  15. Microarray-Based Cancer Prediction Using Soft Computing Approach

    Directory of Open Access Journals (Sweden)

    Xiaosheng Wang

    2009-01-01

    Full Text Available One of the difficulties in using gene expression profiles to predict cancer is how to effectively select a few informative genes to construct accurate prediction models from thousands or ten thousands of genes. We screen highly discriminative genes and gene pairs to create simple prediction models involved in single genes or gene pairs on the basis of soft computing approach and rough set theory. Accurate cancerous prediction is obtained when we apply the simple prediction models for four cancerous gene expression datasets: CNS tumor, colon tumor, lung cancer and DLBCL. Some genes closely correlated with the pathogenesis of specific or general cancers are identified. In contrast with other models, our models are simple, effective and robust. Meanwhile, our models are interpretable for they are based on decision rules. Our results demonstrate that very simple models may perform well on cancerous molecular prediction and important gene markers of cancer can be detected if the gene selection approach is chosen reasonably.

  16. A component based approach to scientific workflow management

    Science.gov (United States)

    Baker, N.; Brooks, P.; Kovacs, Z.; LeGoff, J.-M.; McClatchey, R.

    2001-08-01

    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.

  17. Road traffic management based on self-load-balancing approach

    Directory of Open Access Journals (Sweden)

    Adnane Ahmed

    2016-01-01

    Full Text Available Traffic congestion is one of the most challenging problems for nowadays cities. Several contributions mainly based on V2V (Vehicle-to-Vehicle communication have been published, but most of them have never been applied due to their communication related problems and costs. In this article, a novel cost-effective approach is introduced inspired by social life of insects where direct (V2V communication does not exist anymore. Vehicles are equipped with devices that perform simple tasks, but their interactions with the environment through RSUs (Road Side Units allow the creation of an intelligence which notifies drivers about congested road segments to avoid them. We call this emerging behavior self-load balancing. Description of the fundamentals of this approach and its performance are detailed in this work.

  18. 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.

  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. Cell based therapeutic approach in vascular surgery: application and review

    Directory of Open Access Journals (Sweden)

    Rocca Aldo

    2017-10-01

    Full Text Available Multipotent stem cells - such as mesenchymal stem/stromal cells and stem cells derived from different sources like vascular wall are intensely studied to try to rapidly translate their discovered features from bench to bedside. Vascular wall resident stem cells recruitment, differentiation, survival, proliferation, growth factor production, and signaling pathways transduced were analyzed. We studied biological properties of vascular resident stem cells and explored the relationship from several factors as Matrix Metalloproteinases (MMPs and regulations of biological, translational and clinical features of these cells. In this review we described a translational and clinical approach to Adult Vascular Wall Resident Multipotent Vascular Stem Cells (VW-SCs and reported their involvement in alternative clinical approach as cells based therapy in vascular disease like arterial aneurysms or peripheral arterial obstructive disease.