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Sample records for angiography visual estimation

  1. Grading of carotid artery stenosis with multidetector-row CT angiography: visual estimation or caliper measurements?

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    Waaijer, Annet; Weber, M; van Leeuwen, M S; Kardux, J; Veldhuis, W B; Lo, R; Beek, F J A; Prokop, M

    2009-12-01

    To assess the optimal method for grading carotid artery stenosis with computed tomographic angiography (CTA), we compared visual estimation to caliper measurements, and determined inter-observer variability and agreement relative to digital subtraction angiography (DSA). We included 46 patients with symptomatic carotid stenosis for whom CTA and DSA of 55 carotids was available. Stenosis quantification by CTA using visual estimation (CTA(VE)) (method 1) was compared with caliper measurements using subjectively optimized wide window settings (method 2) or predefined contrast-dependent narrow window settings (method 3). Measurements were independently performed by two radiologists and two residents. To determine accuracy and inter-observer variability, we calculated linear weighted kappa, performed a Bland-Altman analysis and calculated mean difference (bias) and standard deviation of differences (SDD). For inter-observer variability, kappa analysis was "very good" (0.85) for expert observers using CTA(VE) compared with "good" (0.61) for experts using DSA. Compared with DSA, method 1 led to overestimation (bias 5.8-8.0%, SDD 10.6-14.4), method 3 led to underestimation (bias -6.3 to -3.0%, SDD 13.0-18.1). Measurement variability between DSA and visual estimation on CTA (SDD 11.5) is close to the inter-observer variability of repeated measurements on DSA that we found in this study (SDD 11.6). For CTA of carotids, stenosis grading based on visual estimation provides better agreement to grading by DSA compared with stenosis grading based on caliper measurements.

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

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    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.

  3. 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.)

  4. Gallbladder visualization on CT shortly after abdominal angiography with iodixanol

    International Nuclear Information System (INIS)

    Tajima, Hiroyuki; Murakami, Ryusuke; Goto, Shinsuke; Aoyama, Toshiya; Kaizu, Toshihide; Ichikawa, Taro; Kumazaki, Tatsuo; Onda, Masahiko

    1996-01-01

    Fifteen patients underwent CT examination shortly after abdominal angiography with iodixanol. Gallbladder opacification was observed in 13 patients in the absence of clinical evidence of renal impairment. Among them, 2 patients showed a strong opacification on CT. There was no significant relationship between visualization of the gallbladder and the total dose of contrast medium. Gallbladder opacification on CT examination shortly after angiography shows that the hepatobiliary tract is important in the excretion of iodixanol. (author)

  5. Angiography

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    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

  6. Generalised brain edema and brain infarct in ergotamine abuse: Visualization by CT, MR and angiography

    International Nuclear Information System (INIS)

    Toedt, C.; Hoetzinger, H.; Salbeck, R.; Beyer, H.K.

    1989-01-01

    Abuse of ergotamine can release a generalised brain edema and brain infarctions. This can be visualized by CT, MR and angiography. The reason, however, can only be found in the patients history. (orig.) [de

  7. Visual and Quantitative Assessment of Coronary Stenoses at Angiography Versus Fractional Flow Reserve: The Impact of Risk Factors.

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    Adjedj, Julien; Xaplanteris, Panagiotis; Toth, Gabor; Ferrara, Angela; Pellicano, Mariano; Ciccarelli, Giovanni; Floré, Vincent; Barbato, Emanuele; De Bruyne, Bernard

    2017-07-01

    The correlation between angiographic assessment of coronary stenoses and fractional flow reserve (FFR) is weak. Whether and how risk factors impact the diagnostic accuracy of angiography is unknown. We sought to evaluate the diagnostic accuracy of angiography by visual estimate and by quantitative coronary angiography when compared with FFR and evaluate the influence of risk factors (RF) on this accuracy. In 1382 coronary stenoses (1104 patients), percent diameter stenosis by visual estimation (DS VE ) and by quantitative coronary angiography (DS QCA ) was compared with FFR. Patients were divided into 4 subgroups, according to the presence of RFs, and the relationship between DS VE , DS QCA , and FFR was analyzed. Overall, DS VE was significantly higher than DS QCA ( P <0.0001); nonetheless, when examined by strata of DS, DS VE was significantly smaller than DS QCA in mild stenoses, although the reverse held true for severe stenoses. Compared with FFR, a large scatter was observed for both DS VE and DS QCA . When using a dichotomous FFR value of 0.80, C statistic was significantly higher for DS VE than for DS QCA (0.712 versus 0.640, respectively; P <0.001). C statistics for DS VE decreased progressively as RFs accumulated (0.776 for ≤1 RF, 0.750 for 2 RFs, 0.713 for 3 RFs and 0.627 for ≥4 RFs; P =0.0053). In addition, in diabetics, the relationship between FFR and angiographic indices was particularly weak (C statistics: 0.524 for DS VE and 0.511 for DS QCA ). Overall, DS VE has a better diagnostic accuracy than DS QCA to predict the functional significance of coronary stenosis. The predictive accuracy of angiography is moderate in patients with ≤1 RFs, but weakens as RFs accumulate, especially in diabetics. © 2017 American Heart Association, Inc.

  8. Estimation of myocardial volume at risk from CT angiography

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    Zhu, Liangjia; Gao, Yi; Mohan, Vandana; Stillman, Arthur; Faber, Tracy; Tannenbaum, Allen

    2011-03-01

    The determination of myocardial volume at risk distal to coronary stenosis provides important information for prognosis and treatment of coronary artery disease. In this paper, we present a novel computational framework for estimating the myocardial volume at risk in computed tomography angiography (CTA) imagery. Initially, epicardial and endocardial surfaces, and coronary arteries are extracted using an active contour method. Then, the extracted coronary arteries are projected onto the epicardial surface, and each point on this surface is associated with its closest coronary artery using the geodesic distance measurement. The likely myocardial region at risk on the epicardial surface caused by a stenosis is approximated by the region in which all its inner points are associated with the sub-branches distal to the stenosis on the coronary artery tree. Finally, the likely myocardial volume at risk is approximated by the volume in between the region at risk on the epicardial surface and its projection on the endocardial surface, which is expected to yield computational savings over risk volume estimation using the entire image volume. Furthermore, we expect increased accuracy since, as compared to prior work using the Euclidean distance, we employ the geodesic distance in this work. The experimental results demonstrate the effectiveness of the proposed approach on pig heart CTA datasets.

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

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    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.

  10. Visualization of microvessels with in-house micro-angiography

    International Nuclear Information System (INIS)

    Chiku, Masaaki; Nishigami, Kazuhiro; Takeshita, Satoshi

    2005-01-01

    Although therapeutic angiogenesis improved critical limb ischemia in humans, microvessels promoted by therapeutic angiogenesis needed further improvement to be visualized well by conventional angiographic system, because of its limited spatial resolution of 200 μm. We have developed an in-house micro-angiographic system consisting of a high-voltage power X-ray source and a detecting system with high levels of spatial resolution and sensitivity. The in-house microvessel angiographic system demonstrated its ability to evaluate the function of microvessels in vivo, as well as to visualize them with higher precision than the conventional angiographic system. The findings of our study suggest that a novel micro-angiographic system may be useful in evaluating the efficacy of therapeutic angiogenesis in clinical settings. (author)

  11. Significance of Microvascular Function in Visual-Functional Mismatch Between Invasive Coronary Angiography and Fractional Flow Reserve.

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    Yonetsu, Taishi; Murai, Tadashi; Kanaji, Yoshihisa; Lee, Tetsumin; Matsuda, Junji; Usui, Eisuke; Hoshino, Masahiro; Araki, Makoto; Niida, Takayuki; Hada, Masahiro; Ichijo, Sadamitsu; Hamaya, Rikuta; Kanno, Yoshinori; Kakuta, Tsunekazu

    2017-05-31

    Despite a moderate correlation between angiographical stenosis and physiological significance, the mechanism of discordance has not been fully elucidated, particularly regarding the significance of microvascular function. This study sought to clarify whether microvascular function affects visual-functional mismatch between quantitative coronary angiography (QCA) and fractional flow reserve (FFR). We assessed QCA, FFR, coronary flow reserve, and the index of microcirculatory resistance in 849 non-left-main coronary lesions with visually estimated intermediate stenoses from 532 patients. Clinical and lesion-specific characteristics and physiological parameters associated with mismatch and reverse mismatch were studied. Coronary flow reserve and index of microcirculatory resistance showed a weak, but significant, correlation with FFR (R=0.306, P 50%). Among visually nonsignificant lesions, FFR ≤0.80 (reverse mismatch) was observed in 129 lesions (30.6%). Among visually significant lesions, FFR >0.80 (mismatch) were observed in 179 lesions (41.9%). The significant predictors of reverse mismatch were male sex, nonculprit lesions of acute coronary syndrome, left anterior descending artery location, smaller QCA reference diameter, greater QCA-DS, lower coronary flow reserve, and lower index of microcirculatory resistance. Mismatch was associated with right coronary artery location, greater QCA reference diameter, smaller QCA-DS, lesion length, higher coronary flow reserve, and higher index of microcirculatory resistance. There was a high prevalence of visual-functional mismatches between QCA and FFR. The discrepancy was related to clinical characteristics, lesion-specific factors, and microvascular resistance that was undistinguishable by coronary angiography, thus suggesting the importance of physiological lesion assessment. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  12. Inraoperative and Histological Visualization of Disrupted Vulnerable Plaques following Diagnostic Angiography of Moderate Carotid Stenosis

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    Tatsushi Mutoh

    2010-01-01

    Full Text Available Background. Digital subtraction angiography (DSA remains an important tool for diagnosis of carotid stenosis but is associated with risk for periprocedural complications. This is the first report of direct intraoperative and histolopathologic visualization of DSA-related carotid plaque disruption. Case. A 64-year-old man diagnosed to have a 60% right carotid stenosis received diagnostic DSA for therapeutic decision-making. He developed transient left hand numbness and weakness immediately after the procedure. Intraoperative imaging during carotid endarterectomy revealed a fragile plaque with sharp surface laceration and intraplaque hemorrhage at the bifurcation. Microscopy of the specimen demonstrated a large atheromatous plaque with fibrous hypertrophy and intraplaque hemorrhage filled with recent hemorrhagic debris. Conclusion. The visualized carotid lesion was more serious than expected, warning the danger of embolization or occlusion associated with the catheter maneuvers. Thus the highest level of practitioner training and technical expertise that ensures precise assessment of plaque characteristics should be encouraged.

  13. [Contrast enhanced ultrasound can show symptomatic carotid lesions not visualized with magnetic resonance angiography].

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    Baud, J-M; Becker, F; Maurizot, A; Pico, F

    2013-12-01

    We report the cases of two patients who presented symptoms focused on a wall of the common carotid: carotidodynia in one patient and a transient ischemic attack in the other. The B-mode ultrasound showed an enlarged thickened medio-adventitial echostructure with a slightly heterogeneous and iso or hypoechoic appearance. There was no narrowing. Injection of ultrasound contrast led to significant enhancement in the wall reflecting neovascularization secondary to inflammation. Other imaging methods (MR and CT angiography) found no abnormality. At the 3-month follow-up visit, the surface area of the lesions was greatly decreased and the ultrasound contrast enhancement had disappeared. These two cases illustrate how focal lesions of the carotid wall missed on MR and CT angiography can be detected and visualized with B-mode ultrasound contrast enhancement. Contrast enhanced ultrasound leads to the concept of "active lesions" resulting from inflammatory processes that can be readily monitored without radiation. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  14. Comparison of intra-aortic computed tomography angiography to conventional angiography in the presurgical visualization of the Adamkiewicz artery: first results in patients with thoracoabdominal aortic aneurysms

    International Nuclear Information System (INIS)

    Clarencon, Frederic; Maria, Federico di; Cormier, Evelyne; Sourour, Nader; Gabrieli, Joseph; Iosif, Christina; Chiras, Jacques; Gaudric, Julien; Koskas, Fabien; Jenny, Catherine

    2013-01-01

    The aim of this study was to compare the sensitivity of intra-aortic computed tomography angiography (IA-CTA) to that of regular spinal digital subtraction angiography for the presurgical location of the Adamkiewicz artery (AKA). Thirty patients (21 males, 9 females; mean age 64 years) had an IA-CTA for the location of the AKA before surgery of aneurysm (n = 24) or dissection (n = 6) of the thoracoabdominal aorta. After femoral artery puncture, a pigtail catheter was positioned at the origin of the descending aorta. CT acquisition was performed with an intra-aortic iodinated contrast media injection (15 mL/s, 120 mL). The visualization of the AKA and the location of the feeder(s) to the AKA were independently evaluated by two observers. Interrater agreement was calculated using a kappa test. Spinal angiogram by selective catheterization was systematically performed to confirm the results of the IA-CTA. The AKA was visualized by the IA-CTA in 27/30 cases (90 %); in 26/31 (84 %) cases, the continuity with the aorta was satisfactorily seen. Interrater agreement was good for the visualization of the AKA and its feeder(s): 0.625 and 0.87, respectively. In 75 % of the cases for which the AKA was visualized, the selective catheterization confirmed the results of the IA-CTA. In the remaining 25 % of the cases, the selective catheterization could not be performed due to marked vessels' tortuosity or ostium stenosis. IA-CTA is a feasible technique in a daily practice that presents a good sensitivity for the location of the AKA. (orig.)

  15. Visualization of Radial Peripapillary Capillaries Using Optical Coherence Tomography Angiography: The Effect of Image Averaging.

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    Shelley Mo

    Full Text Available To assess the effect of image registration and averaging on the visualization and quantification of the radial peripapillary capillary (RPC network on optical coherence tomography angiography (OCTA.Twenty-two healthy controls were imaged with a commercial OCTA system (AngioVue, Optovue, Inc.. Ten 10x10° scans of the optic disc were obtained, and the most superficial layer (50-μm slab extending from the inner limiting membrane was extracted for analysis. Rigid registration was achieved using ImageJ, and averaging of each 2 to 10 frames was performed in five ~2x2° regions of interest (ROI located 1° from the optic disc margin. The ROI were automatically skeletonized. Signal-to-noise ratio (SNR, number of endpoints and mean capillary length from the skeleton, capillary density, and mean intercapillary distance (ICD were measured for the reference and each averaged ROI. Repeated measures analysis of variance was used to assess statistical significance. Three patients with primary open angle glaucoma were also imaged to compare RPC density to controls.Qualitatively, vessels appeared smoother and closer to histologic descriptions with increasing number of averaged frames. Quantitatively, number of endpoints decreased by 51%, and SNR, mean capillary length, capillary density, and ICD increased by 44%, 91%, 11%, and 4.5% from single frame to 10-frame averaged, respectively. The 10-frame averaged images from the glaucomatous eyes revealed decreased density correlating to visual field defects and retinal nerve fiber layer thinning.OCTA image registration and averaging is a viable and accessible method to enhance the visualization of RPCs, with significant improvements in image quality and RPC quantitative parameters. With this technique, we will be able to non-invasively and reliably study RPC involvement in diseases such as glaucoma.

  16. Isolated unilateral absence of the right pulmonary artery in two cats visualized by computed tomography angiography

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    Tyler JM Jordan

    2016-10-01

    Full Text Available Case series summary Two cats were evaluated for progressive exercise intolerance, dyspnea and unilateral infiltrate of the left lung. Computed tomography angiography (CTA revealed absence of the right pulmonary artery in both cats with systemic arterial collateral vessels perfusing the right segmental pulmonary arteries. In one case, the collateral vessels arose from the esophageal artery, while in the other case they derived off the right costocervical trunk. One cat was diagnosed with pulmonary hypertension and was euthanized owing to progressive respiratory distress despite medical management with sildenafil, pimobendan, clopidogrel and furosemide. The other cat, without echocardiographic evidence of pulmonary hypertension, was successfully managed with furosemide and enalapril for more than 4 years. Relevance and novel information CTA allowed visualization of a rare congenital heart malformation, unilateral absence of the right pulmonary artery, in two cats and accurately characterized the source of collateral blood supply to the affected lung. Severe pulmonary hypertension may be a negative prognostic factor in cats with this condition as medical therapy in the cat without evidence of pulmonary hypertension resolved clinical signs, while the cat with severe pulmonary hypertension died from the disease.

  17. Radial Peripapillary Capillary Network Visualized Using Wide-Field Montage Optical Coherence Tomography Angiography.

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    Mase, Tomoko; Ishibazawa, Akihiro; Nagaoka, Taiji; Yokota, Harumasa; Yoshida, Akitoshi

    2016-07-01

    We quantitatively analyzed the features of a radial peripapillary capillary (RPC) network visualized using wide-field montage optical coherence tomography (OCT) angiography in healthy human eyes. Twenty eyes of 20 healthy subjects were recruited. En face 3 × 3-mm OCT angiograms of multiple locations in the posterior pole were acquired using the RTVue XR Avanti, and wide-field montage images of the RPC were created. To evaluate the RPC density, the montage images were binarized and skeletonized. The correlation between the RPC density and the retinal nerve fiber layer (RNFL) thickness measured by an OCT circle scan was investigated. The RPC at the temporal retina was detected as far as 7.6 ± 0.7 mm from the edge of the optic disc but not around the perifoveal area within 0.9 ± 0.1 mm of the fovea. Capillary-free zones beside the first branches of the arterioles were significantly (P optic disc edge were 13.6 ± 0.8, 11.9 ± 0.9, and 10.4 ± 0.9 mm-1. The RPC density also was correlated significantly (r = 0.64, P network. The RPC is present in the superficial peripapillary retina in proportion to the RNFL thickness, supporting the idea that the RPC may be the vascular network primarily responsible for RNFL nourishment.

  18. Catheter Angiography

    Medline Plus

    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 ...

  19. Use of performance curves in estimating number of procedures required to achieve proficiency in coronary angiography

    DEFF Research Database (Denmark)

    Räder, Sune B E W; Jørgensen, Erik; Bech, Bo

    2011-01-01

    .001 for all parameters. To approach the experts' level of DAP and contrast media use, trainees need 394 and 588 procedures, respectively. Performance curves showed large individual differences in the development of competence. Conclusion: On average, trainees needed 300 procedures to reach sufficient level...... needed for trainees to reach recommended reference levels was estimated as 226 and 353, for DAP and use of contrast media, respectively. After 300 procedures, trainees' procedure time, fluoroscopy time, DAP, and contrast media volume were significantly higher compared with experts' performance, P ...Background: Current guidelines in cardiology training programs recommend 100-300 coronary angiography procedures for certification. We aimed to assess the number of procedures needed to reach sufficient proficiency. Methods: Procedure time, fluoroscopy time, dose area product (DAP), and contrast...

  20. Exploiting magnetic resonance angiography imaging improves model estimation of BOLD signal.

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    Zhenghui Hu

    Full Text Available The change of BOLD signal relies heavily upon the resting blood volume fraction ([Formula: see text] associated with regional vasculature. However, existing hemodynamic data assimilation studies pretermit such concern. They simply assign the value in a physiologically plausible range to get over ill-conditioning of the assimilation problem and fail to explore actual [Formula: see text]. Such performance might lead to unreliable model estimation. In this work, we present the first exploration of the influence of [Formula: see text] on fMRI data assimilation, where actual [Formula: see text] within a given cortical area was calibrated by an MR angiography experiment and then was augmented into the assimilation scheme. We have investigated the impact of [Formula: see text] on single-region data assimilation and multi-region data assimilation (dynamic cause modeling, DCM in a classical flashing checkerboard experiment. Results show that the employment of an assumed [Formula: see text] in fMRI data assimilation is only suitable for fMRI signal reconstruction and activation detection grounded on this signal, and not suitable for estimation of unobserved states and effective connectivity study. We thereby argue that introducing physically realistic [Formula: see text] in the assimilation process may provide more reliable estimation of physiological information, which contributes to a better understanding of the underlying hemodynamic processes. Such an effort is valuable and should be well appreciated.

  1. Estimation of visual motion in image sequences

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    1994-01-01

    The problem of estimation of visual motion from sequences of images has been considered within a framework consisting of three stages of processing. First the extraction of motion invariants, secondly a local measurement of visual motion, and third integration of local measurements in conjunction...... with a priori knowledge. We have surveyed a series of attempts to extract motion invariants. Specifically we have illustrate the use of local Fourier phase. The Fourier phase is shown to define the local shape of the signal, thus accurately localizing an event. Different strategies for local measurement...... are given. In particular we have investigated the use of smoothness of the second order derivatives, and the use of edge model and prior destributions for the field that favor discontinuities to characterize the motion field. A succesful implementation of a temporal interpolation in a sequence of weather...

  2. 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 ...

  3. Multivariate density estimation theory, practice, and visualization

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    Scott, David W

    2015-01-01

    David W. Scott, PhD, is Noah Harding Professor in the Department of Statistics at Rice University. The author of over 100 published articles, papers, and book chapters, Dr. Scott is also Fellow of the American Statistical Association (ASA) and the Institute of Mathematical Statistics. He is recipient of the ASA Founder's Award and the Army Wilks Award. His research interests include computational statistics, data visualization, and density estimation. Dr. Scott is also Coeditor of Wiley Interdisciplinary Reviews: Computational Statistics and previous Editor of the Journal of Computational and

  4. Estimation of radiation exposure of prospectively triggered 128-slice computed tomography coronary angiography

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    Ketelsen, D.; Fenchel, M.; Thomas, C.; Boehringer, N.; Tsiflikas, I.; Kaempf, M.; Syha, R.; Claussen, C.D.; Heuschmid, M. [Tuebingen Univ. (Germany). Abt. fuer Diagnostische und Interventionelle Radiologie; Buchgeister, M. [Tuebingen Univ. (Germany). Medizinische Physik

    2010-12-15

    Purpose: To estimate the effective dose of prospectively triggered computed tomography coronary angiography (CTCA) in step-and-shoot (SAS) mode, depending on the tube current and tube voltage modulation. Materials and Methods: For dose measurements, an Alderson-Rando-phantom equipped with thermoluminescent dosimeters was used. The effective dose was calculated according to ICRP 103. Exposure was performed on a 128-slice single source scanner providing a collimation of 128 x 0.6 mm and a rotation time of 0.38 seconds. CTCA in the SAS mode was acquired with variation of the tube current (160, 240, 320 mAs) and tube voltage (100, 120, 140 kV) at a simulated heart rate of 60 beats per minute and a scan range of 13.5 cm. Results: Depending on gender, tube current and tube voltage, the effective dose of a CTCA in SAS mode varies from 2.8 to 10.8 mSv. Due to breast tissue in the primary scan range, exposure in the case of females showed an increase of up to 60.0 {+-}.4 % compared to males. The dose reduction achieved by a reduction of tube current showed a significant positive, linear correlation to effective dose with a possible decrease in the effective dose of up to 60.4 % (r = 0.998; p = 0.044). Disproportionately high, the estimated effective dose can be reduced by using a lower tube voltage with a dose reduction of up to 52.4 %. Conclusion: Further substantial dose reduction of low-dose CTCA in SAS mode can be achieved by adapting the tube current and tube voltage and should be implemented in the clinical routine, i.e. adapting those protocol parameters to patient body weight. (orig.).

  5. Estimation of intrathoracic arterial diameter by means of computed tomographic angiography in Hispaniolan Amazon parrots.

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    Beaufrère, Hugues; Rodriguez, Daniel; Pariaut, Romain; Gaschen Dvm, Lorrie; Schnellbacher, Rodney; Nevarez, Javier G; Tully, Thomas N

    2011-02-01

    To establish a computed tomography (CT)-angiography protocol and measure the diameters of major arteries in parrots. 13 Hispaniolan Amazon parrots (Amazona ventralis). 16-slice CT scanning was used to measure the apparent diameter of the ascending aorta, abdominal aorta, pulmonary arteries, and brachiocephalic trunk. Before scanning, all birds underwent ECG and echocardiographic assessment and were considered free of detectable cardiovascular diseases. Each bird was anesthetized, and a precontrast helical CT scan was performed. Peak aortic enhancement was established with a test bolus technique via dynamic axial CT scan over a predetermined single slice. An additional bolus of contrast medium was then injected, and a helical CT-angiography scan was performed immediately afterward. Arterial diameter measurements were obtained by 2 observers via various windows before and after injection, and intra- and interobserver agreement was assessed. Reference limits were determined for arterial diameter measurements before and after contrast medium administration in pulmonary, mediastinal, and manual angiography windows. Ratios of vertebral body diameter to keel length were also calculated. Intraobserver agreement was high (concordance correlation coefficients ≥ 0.95); interobserver agreement was medium to high (intraclass correlation coefficients ≥ 0.65). CT-angiography was safe and is of potential diagnostic value in parrots. We recommend performing the angiography immediately after IV injection of 3 mL of iohexol/kg. Arterial diameter measurements at the described locations were reliable.

  6. Visual acuity estimation from simulated images

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    Duncan, William J.

    Simulated images can provide insight into the performance of optical systems, especially those with complicated features. Many modern solutions for presbyopia and cataracts feature sophisticated power geometries or diffractive elements. Some intraocular lenses (IOLs) arrive at multifocality through the use of a diffractive surface and multifocal contact lenses have a radially varying power profile. These type of elements induce simultaneous vision as well as affecting vision much differently than a monofocal ophthalmic appliance. With myriad multifocal ophthalmics available on the market it is difficult to compare or assess performance in ways that effect wearers of such appliances. Here we present software and algorithmic metrics that can be used to qualitatively and quantitatively compare ophthalmic element performance, with specific examples of bifocal intraocular lenses (IOLs) and multifocal contact lenses. We anticipate this study, methods, and results to serve as a starting point for more complex models of vision and visual acuity in a setting where modeling is advantageous. Generating simulated images of real- scene scenarios is useful for patients in assessing vision quality with a certain appliance. Visual acuity estimation can serve as an important tool for manufacturing and design of ophthalmic appliances.

  7. Improved visualization of intracranial vessels by gradient moment nulling in hybrid of opposite-contrast magnetic resonance angiography (HOP MRA)

    International Nuclear Information System (INIS)

    Azuma, Toshiya; Kodama, Takao; Yano, Takanori; Suzuki, Masayuki; Kimura, Tokunori; Tamaribuchi, Youko

    2010-01-01

    Hybrid of opposite-contrast (HOP) magnetic resonance angiography (MRA) is a new method that combines the advantages of 3-dimensional (3D) time-of-flight (TOF) MRA and black-blood (BB) MRA without prolonging acquisition time. In phantom and clinical studies, we focused on image differences when we applied gradient moment nulling (GMN) to 2 or 3 axes in the first echo. We made an original phantom with a semicircular tube of 3- and 5-mm internal diameter, with flow rate in the tube of 0, 20, 60, 80, or 120 cm/s. In original images of the phantom obtained with TOF MRA and flow-sensitive BB MRA and in filter frequency-weighted subtraction (FWS) processed images acquired with HOP MRA, we measured the contrast-to-noise ratio (CNR) of both the inside and outside of the tubes. In FWS processed images with GMN applied to 2 axes, the CNR was high at various flow rates in both straight and bending portions of the tubes in comparison with TOF images. In a clinical study in 15 patients, we evaluated vessel visualization in images obtained using conventional TOF MRA with magnetization transfer contrast (MTC) and HOP MRA. In clinical studies, visualization scores of HOP MRA were equivalent to those of conventional TOF MRA in the bilateral internal carotid arteries (ICA) and inferior in the basilar arteries. However, visualization of the peripheral portion of the middle cerebral artery (MCA) improved significantly in HOP MRA with GMN applied to 2 and 3 axes. Visualization of the main trunk of the ICA and MCA was superior in HOP MRA with GMN applied to 2 axes. HOP MRA with 2-axis GMN may be useful for excellent visualization of both major arteries and peripheral vessels in the head. (author)

  8. 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

  9. Catheter Angiography

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    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 ...

  10. 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 ...

  11. 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 ...

  12. Extrahepatic Arteries Originating from Hepatic Arteries: Analysis Using CT During Hepatic Arteriography and Visualization on Digital Subtraction Angiography

    Energy Technology Data Exchange (ETDEWEB)

    Ozaki, Kumi, E-mail: ozakik-rad@umin.org [Kanazawa University Graduate School of Medical Science, Department of Radiology (Japan); Kobayashi, Satoshi [Kanazawa University Graduate School of Medical Science, Department of Quantum Medicine Technology (Japan); Matsui, Osamu; Minami, Tetsuya; Koda, Wataru; Gabata, Toshifumi [Kanazawa University Graduate School of Medical Science, Department of Radiology (Japan)

    2017-06-15

    PurposeTo investigate the prevalence and site of origin of extrahepatic arteries originating from hepatic arteries on early phase CT during hepatic arteriography (CTHA) was accessed. Visualization of these elements on digital subtraction hepatic angiography (DSHA) was assessed using CTHA images as a gold standard.Materials and MethodsA total of 943 patients (mean age 66.9 ± 10.3 years; male/female, 619/324) underwent CTHA and DSHA. The prevalence and site of origin of extrahepatic arteries were accessed using CTHA and visualized using DSHA.ResultsIn 924 (98.0%) patients, a total of 1555 extrahepatic branches, representing eight types, were found to originate from hepatic arteries on CTHA. CTHA indicated the following extrahepatic branch prevalence rates: right gastric artery, 890 (94.4%); falciform artery, 386 (40.9%); accessory left gastric artery, 161 (17.1%); left inferior phrenic artery (IPA), 43 (4.6%); posterior superior pancreaticoduodenal artery, 33 (3.5%); dorsal pancreatic artery, 26 (2.8%); duodenal artery, 12 (1.3%); and right IPA, 4 (0.4%). In addition, 383 patients (40.6%) had at least one undetectable branch on DSHA. The sensitivity, specificity, and accuracy of visualization on DSHA were as follows: RGA, 80.0, 86.8, and 80.4%; falciform artery, 53.9, 97.7, and 80.0%; accessory LGA, 64.6, 98.6, and 92.3%; left IPA, 76.7, 99.8, and 98.7%; PSPDA, 100, 99.7, and 99.9%; dorsal pancreatic artery, 57.7, 100, and 98.8%; duodenal artery, 8.3, 99.9, and 98.7%; and right IPA, 0, 100, and 99.6%, respectively.ConclusionExtrahepatic arteries originating from hepatic arteries were frequently identified on CTHA images. These arteries were frequently overlooked on DSHA.

  13. Glaucoma Diagnostic Capabilities of Foveal Avascular Zone Parameters Using Optical Coherence Tomography Angiography According to Visual Field Defect Location.

    Science.gov (United States)

    Kwon, Junki; Choi, Jaewan; Shin, Joong Won; Lee, Jiyun; Kook, Michael S

    2017-12-01

    To assess the diagnostic ability of foveal avascular zone (FAZ) parameters to discriminate glaucomatous eyes with visual field defects (VFDs) in different locations (central vs. peripheral) from normal eyes. Totally, 125 participants were separated into 3 groups: normal (n=45), glaucoma with peripheral VFD (PVFD, n=45), and glaucoma with central VFD (CVFD, n=35). The FAZ area, perimeter, and circularity and parafoveal vessel density were calculated from optical coherence tomography angiography images. The diagnostic ability of the FAZ parameters and other structural parameters was determined according to glaucomatous VFD location. Associations between the FAZ parameters and central visual function were evaluated. A larger FAZ area and longer FAZ perimeter were observed in the CVFD group than in the PVFD and normal groups. The FAZ area, perimeter, and circularity were better in differentiating glaucomatous eyes with CVFDs from normal eyes [areas under the receiver operating characteristic curves (AUC), 0.78 to 0.88] than in differentiating PVFDs from normal eyes (AUC, 0.51 to 0.64). The FAZ perimeter had a similar AUC value to the circumpapillary retinal nerve fiber layer and macular ganglion cell-inner plexiform layer thickness for differentiating eyes with CVFDs from normal eyes (all P>0.05, the DeLong test). The FAZ area was significantly correlated with central visual function (β=-112.7, P=0.035, multivariate linear regression). The FAZ perimeter had good diagnostic capability in differentiating glaucomatous eyes with CVFDs from normal eyes, and may be a potential diagnostic biomarker for detecting glaucomatous patients with CVFDs.

  14. Improving visual estimates of cervical spine range of motion.

    Science.gov (United States)

    Hirsch, Brandon P; Webb, Matthew L; Bohl, Daniel D; Fu, Michael; Buerba, Rafael A; Gruskay, Jordan A; Grauer, Jonathan N

    2014-11-01

    Cervical spine range of motion (ROM) is a common measure of cervical conditions, surgical outcomes, and functional impairment. Although ROM is routinely assessed by visual estimation in clinical practice, visual estimates have been shown to be unreliable and inaccurate. Reliable goniometers can be used for assessments, but the associated costs and logistics generally limit their clinical acceptance. To investigate whether training can improve visual estimates of cervical spine ROM, we asked attending surgeons, residents, and medical students at our institution to visually estimate the cervical spine ROM of healthy subjects before and after a training session. This training session included review of normal cervical spine ROM in 3 planes and demonstration of partial and full motion in 3 planes by multiple subjects. Estimates before, immediately after, and 1 month after this training session were compared to assess reliability and accuracy. Immediately after training, errors decreased by 11.9° (flexion-extension), 3.8° (lateral bending), and 2.9° (axial rotation). These improvements were statistically significant. One month after training, visual estimates remained improved, by 9.5°, 1.6°, and 3.1°, respectively, but were statistically significant only in flexion-extension. Although the accuracy of visual estimates can be improved, clinicians should be aware of the limitations of visual estimates of cervical spine ROM. Our study results support scrutiny of visual assessment of ROM as a criterion for diagnosing permanent impairment or disability.

  15. Reduction of the estimated radiation dose and associated patient risk with prospective ECG-gated 256-slice CT coronary angiography

    International Nuclear Information System (INIS)

    Efstathopoulos, E P; Kelekis, N L; Pantos, I; Brountzos, E; Argentos, S; Grebac, J; Ziaka, D; Seimenis, I; Katritsis, D G

    2009-01-01

    Computed tomography (CT) coronary angiography has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but high radiation doses have been reported. Prospective ECG-gating using a 'step-and-shoot' axial scanning protocol has been shown to reduce radiation exposure effectively while maintaining diagnostic accuracy. 256-slice scanners with 80 mm detector coverage have been currently introduced into practice, but their impact on radiation exposure has not been adequately studied. The aim of this study was to assess radiation doses associated with CT coronary angiography using a 256-slice CT scanner. Radiation doses were estimated for 25 patients scanned with either prospective or retrospective ECG-gating. Image quality was assessed objectively in terms of mean CT attenuation at selected regions of interest on axial coronary images and subjectively by coronary segment quality scoring. It was found that radiation doses associated with prospective ECG-gating were significantly lower than retrospective ECG-gating (3.2 ± 0.6 mSv versus 13.4 ± 2.7 mSv). Consequently, the radiogenic fatal cancer risk for the patient is much lower with prospective gating (0.0176% versus 0.0737%). No statistically significant differences in image quality were observed between the two scanning protocols for both objective and subjective quality assessments. Therefore, prospective ECG-gating using a 'step-and-shoot' protocol that covers the cardiac anatomy in two axial acquisitions effectively reduces radiation doses in 256-slice CT coronary angiography without compromising image quality.

  16. 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

  17. 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)

  18. 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).

  19. 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 ...

  20. 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 ...

  1. 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 ...

  2. 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 ...

  3. 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 ...

  4. Longitudinal visualization of vascular occlusion, reperfusion, and remodeling in a zebrafish model of retinal vascular leakage using OCT angiography

    Science.gov (United States)

    Spitz, Kathleen; Bozic, Ivan; Desai, Vineet; Rao, Gopikrishna M.; Pollock, Lana M.; Anand-Apte, Bela; Tao, Yuankai K.

    2017-02-01

    Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are two of the leading causes of blindness and visual impairment in the world. Neovascularization results in severe vision loss in DR and AMD and, thus, there is an unmet need to identify mechanisms of pathogenesis and novel anti-angiogenic therapies. Zebrafish is a leading model organism for studying human disease pathogenesis, and the highly conserved drug activity between zebrafish and humans and their ability to readily absorb small molecules dissolved in water has benefited pharmaceutical discovery. Here, we use optical coherence tomography (OCT) and OCT angiography (OCT-A) to perform noninvasive, in vivo retinal imaging in a zebrafish model of vascular leakage. Zebrafish were treated with diethylaminobenzaldehyde (DEAB) to induce vascular leakage and imaged with OCT and OCT-A at six time points over two weeks: baseline one day before treatment and one, three, six, eight, and ten days post treatment. Longitudinal functional imaging showed significant vascular response immediately after DEAB treatment. Observed vascular changes included partial or complete vascular occlusion immediately after treatment and reperfusion during a two-week period. Increased vascular tortuosity several days post treatment indicated remodeling, and bifurcations and collateral vessel formation were also observed. In addition, significant treatment response variabilities were observed in the contralateral eye of the same animal. Anatomical and functional normalization was observed in most animals by ten days post treatment. These preliminary results motivate potential applications of OCT-A as a tool for studying pathogenesis and therapeutic screening in zebrafish models of retinal vascular disease.

  5. Smile line assessment comparing quantitative measurement and visual estimation

    NARCIS (Netherlands)

    Geld, P. Van der; Oosterveld, P.; Schols, J.; Kuijpers-Jagtman, A.M.

    2011-01-01

    INTRODUCTION: Esthetic analysis of dynamic functions such as spontaneous smiling is feasible by using digital videography and computer measurement for lip line height and tooth display. Because quantitative measurements are time-consuming, digital videography and semiquantitative (visual) estimation

  6. 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 ( ...

  7. Interstudy repeatability of left and right ventricular volume estimations by serial-gated tomographic radionuclide angiographies using a cadmium-zinc-telluride detector gamma camera

    DEFF Research Database (Denmark)

    Jensen, Maria Maj; Haase, Christine; Zerahn, Bo

    2015-01-01

    PURPOSE: Estimation of left ventricular ejection fraction (LVEF) with 99MTc-HSA equilibrium radionuclide angiography (RA) is frequently used for assessing cardiac function. The purpose of this study was to investigate the interstudy repeatability of left (LV) and right (RV) ventricular volume...

  8. Visualization of the renal venous system by renal arteriography with digital subtraction angiography

    International Nuclear Information System (INIS)

    Nagai, Jun

    1989-01-01

    The purpose of this study was to obtain vivid and precise images of intrarenal venous branching using DSA for renal arteriography. The type of system used was an ADAC DPS-4100C with 70-80 kVp, and 320 mA, 25-50 msec at 6 frames/sec. The duration was 10 sec and the matrix size was 512x512. In order to retain clear subtracted images of intrarenal venous branching with minimal noise the three frames were selected on the time-density curve of DSA: (Fig.3). 1) a frame on which renal arteries disappear (frame X), 2) the frame with highest renal venous density value as (frame Y), 3) the difference of the nephrogram density between X and Y frames in which only the density of the nephrogram decreases (frame Z). The mask image is the image subtracted by the equation of the weighted averaging method on X and Z frame and is subtracted from the image of Y frame in the final step. By this method, 40 kidneys in 36 patients were studied, and the intrarenal venous branches up to the interlobar vein was clearly demonstrated in 28 of these cases (70%). This method is useful to estimate the extent of intrarenal lesions and detect abnormal renal blood flow compared with conventional temporal subtraction method. (author)

  9. In Vivo Validation of a Blood Vector Velocity Estimator with MR Angiography

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Lindskov; Udesen, Jesper; Thomsen, Carsten

    2009-01-01

    Conventional Doppler methods for blood velocity estimation only estimate the velocity component along the ultrasound beam direction. This implies that a Doppler angle under examination close to 90° results in unreliable information about the true blood direction and blood velocity. The novel method...... transverse oscillation (TO), which combines estimates of the axial and the transverse velocity components in the scan plane, makes it possible to estimate the vector velocity of the blood regardless of the Doppler angle. The present study evaluates the TO method with magnetic resonance phase contrast......° for TO measurements. The correlation between the stroke volume estimated by TO and MRA was 0.91 (p

  10. VBioindex: A Visual Tool to Estimate Biodiversity

    Directory of Open Access Journals (Sweden)

    Dong Su Yu

    2015-09-01

    Full Text Available Biological diversity, also known as biodiversity, is an important criterion for measuring the value of an ecosystem. As biodiversity is closely related to human welfare and quality of life, many efforts to restore and maintain the biodiversity of species have been made by government agencies and non-governmental organizations, thereby drawing a substantial amount of international attention. In the fields of biological research, biodiversity is widely measured using traditional statistical indices such as the Shannon-Wiener index, species richness, evenness, and relative dominance of species. However, some biologists and ecologists have difficulty using these indices because they require advanced mathematical knowledge and computational techniques. Therefore, we developed VBioindex, a user-friendly program that is capable of measuring the Shannon-Wiener index, species richness, evenness, and relative dominance. VBioindex serves as an easy to use interface and visually represents the results in the form of a simple chart and in addition, VBioindex offers functions for long-term investigations of datasets using time-series analyses.

  11. Removing label ambiguity in learning-based visual saliency estimation.

    Science.gov (United States)

    Li, Jia; Xu, Dong; Gao, Wen

    2012-04-01

    Visual saliency is a useful clue to depict visually important image/video contents in many multimedia applications. In visual saliency estimation, a feasible solution is to learn a "feature-saliency" mapping model from the user data obtained by manually labeling activities or eye-tracking devices. However, label ambiguities may also arise due to the inaccurate and inadequate user data. To process the noisy training data, we propose a multi-instance learning to rank approach for visual saliency estimation. In our approach, the correlations between various image patches are incorporated into an ordinal regression framework. By iteratively refining a ranking model and relabeling the image patches with respect to their mutual correlations, the label ambiguities can be effectively removed from the training data. Consequently, visual saliency can be effectively estimated by the ranking model, which can pop out real targets and suppress real distractors. Extensive experiments on two public image data sets show that our approach outperforms 11 state-of-the-art methods remarkably in visual saliency estimation.

  12. Visualization of microaneurysms using optical coherence tomography angiography: comparison of OCTA en face, OCT B-scan, OCT en face, FA, and IA images.

    Science.gov (United States)

    Hamada, Masafumi; Ohkoshi, Kishiko; Inagaki, Keiji; Ebihara, Nobuyuki; Murakami, Akira

    2018-03-01

    To compare the visualization of microaneurysms (MAs) in patients with diabetic retinopathy (DR) using optical coherence tomography angiography (OCTA) with that using fluorescein angiography (FA). Prospective, clinical, and experimental. This study was a prospective evaluation of imaging technology. Thirty-seven eyes of 33 patients with DR were scanned using an OCTA instrument. The 83 MAs that were confirmed on OCT B-scan and OCT en face images were evaluated using OCTA, and these findings were compared with those evaluated using FA. Of the 83 MAs confirmed on OCT B-scan images, 73 (88%) were clearly visualized on the OCTA en face images as nodular or comma-shaped structures, while the remaining 12% did not present with a typical MA or vascular structure on the OCTA en face images at the relevant positions. Seventy-four of the 83 MAs (87%) confirmed on the OCT B-scan images presented as punctate hyperfluorescent spots on the FA images. On the FA images, 8 of 9 (88%) MAs absent on the OCTA en face images presented as hyperfluorescent spots. Visualization of the MAs on the OCTA en face images did not correlate with the OCT B-scan images of the MA lumens (open, closed, or heterogeneous). For diabetic maculopathy, OCTA en face images do not present with comprehensive MAs images, indicating that some MAs might be overlooked with OCTA en face images.

  13. High-resolution coronary MR angiography for evaluation of patients with anomalous coronary arteries: visualization of the intramural segment

    Energy Technology Data Exchange (ETDEWEB)

    Biko, David M. [UCSF Benioff Children' s Hospital Oakland, Department of Diagnostic Imaging, Oakland, CA (United States); The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); Chung, Claudia; Chung, Taylor [UCSF Benioff Children' s Hospital Oakland, Department of Diagnostic Imaging, Oakland, CA (United States); Hitt, David M. [Philips Healthcare, Cleveland, OH (United States); Kurio, Gregory [UCSF Benioff Children' s Hospital Oakland, Department of Cardiology, Oakland, CA (United States); Reinhartz, Olaf [UCSF Benioff Children' s Hospital Oakland, Department of Cardiac Surgery, Oakland, CA (United States)

    2015-08-15

    Anomalous origin of the coronary artery from the contralateral coronary sinus is a rare coronary anomaly associated with sudden death. The inter-arterial course is most closely associated with sudden death, but it has been suggested that the presence of an intramural segment of a right anomalous coronary is associated with more symptoms and therefore may be an important criterion for intervention in these patients. To demonstrate that MR angiography can accurately determine the presence or absence of an intramural segment in an anomalous coronary artery. All studies of children who underwent MR angiography for the evaluation of an anomalous coronary artery were retrospectively reviewed by two pediatric radiologists in consensus. Criteria for an intramural anomalous coronary artery were the presence of a small or slit-like ostium and the relative smaller size of the proximal intramural portion of the coronary artery in relation to the more distal epicardial coronary artery. The anomalous coronary artery was classified as not intramural if these two findings were absent. These findings were correlated with operative reports confirming the presence or absence of an intramural segment. Twelve patients (86%) met MR angiography criteria for the presence of an intramural course. Only 2 patients (14%) met MR angiography criteria for a non-intramural course. When correlating with intraoperative findings, MR angiography was successful in distinguishing between intramural and non-intramural anomalous coronary arteries in all cases (P = 0.01). MR angiography may be able to reliably identify the intramural segment of an anomalous coronary artery in older children using the imaging criteria of a small or slit-like ostium and relative decrease in size of the proximal portion of the anomalous coronary artery compared to the distal portion of the anomalous coronary artery. Determining the presence of the intramural segment may help with surgical planning and may be an important

  14. Prospective Randomized Trial on Radiation Dose Estimates of CT Angiography Applying Iterative Image Reconstruction: The PROTECTION V Study.

    Science.gov (United States)

    Deseive, Simon; Chen, Marcus Y; Korosoglou, Grigorios; Leipsic, Jonathon; Martuscelli, Eugenio; Carrascosa, Patricia; Mirsadraee, Saeed; White, Charles; Hadamitzky, Martin; Martinoff, Stefan; Menges, Anna-Leonie; Bischoff, Bernhard; Massberg, Steffen; Hausleiter, Jörg

    2015-08-01

    The purpose of this study was to assess the potential of iterative image reconstruction (IR) of images for radiation dose reduction in coronary computed tomography angiography (CTA). Therefore, IR in combination with 30% tube current reduction was compared with standard scanning with filtered back projection (FBP) reconstruction. Lately, new IR techniques with advanced raw data processing have been introduced by different computed tomography vendors, thus allowing for either image noise reduction at unchanged radiation dose levels or radiation dose reductions at comparable image noise levels. In this prospective, multicenter, multivendor noninferiority trial, we randomized 400 consecutive patients to 1 of 2 groups: a control group using standard FBP image reconstruction and standard tube current or an interventional group using IR technique and 30% tube current reduction. The primary endpoint was to demonstrate noninferiority in image quality (IQ) in the IR group. IQ was assessed on a 4-point scale (1, nondiagnostic IQ; 4, excellent IQ). Secondary endpoints included total radiation dose estimates and the rate of downstream testing during 30-day follow-up. Median IQ in the IR group was noninferior compared with the conventional FBP group (IR, 3.5 [interquartile range: 3.0 to 4.0]; FBP, 3.4 [interquartile range: 2.8 to 4.0], p for noninferiority <0.016). The radiation exposure was significantly lower in the IR group (median dose-length-product 157 [interquartile range: 114 to 239] mGy·cm vs. 222 [interquartile range: 141 to 319] mGy·cm for IR vs. FBP, respectively, p < 0.0001). The rate of downstream testing did not differ significantly (7.7% vs. 7.9% for IR vs. FBP, respectively, p = 0.94). Coronary CTA image quality is maintained with the combined use of a 30% reduced tube current and IR algorithms when compared with conventional FBP image reconstruction techniques and standard tube current. (Prospective Randomized Trial On RadiaTion Dose Estimates Of CT AngIOgraphy

  15. Cortico-Cortical Receptive Field Estimates in Human Visual Cortex

    Directory of Open Access Journals (Sweden)

    Koen V Haak

    2012-05-01

    Full Text Available Human visual cortex comprises many visual areas that contain a map of the visual field (Wandell et al 2007, Neuron 56, 366–383. These visual field maps can be identified readily in individual subjects with functional magnetic resonance imaging (fMRI during experimental sessions that last less than an hour (Wandell and Winawer 2011, Vis Res 718–737. Hence, visual field mapping with fMRI has been, and still is, a heavily used technique to examine the organisation of both normal and abnormal human visual cortex (Haak et al 2011, ACNR, 11(3, 20–21. However, visual field mapping cannot reveal every aspect of human visual cortex organisation. For example, the information processed within a visual field map arrives from somewhere and is sent to somewhere, and visual field mapping does not derive these input/output relationships. Here, we describe a new, model-based analysis for estimating the dependence between signals in distinct cortical regions using functional magnetic resonance imaging (fMRI data. Just as a stimulus-referred receptive field predicts the neural response as a function of the stimulus contrast, the neural-referred receptive field predicts the neural response as a function of responses elsewhere in the nervous system. When applied to two cortical regions, this function can be called the cortico-cortical receptive field (CCRF. We model the CCRF as a Gaussian-weighted region on the cortical surface and apply the model to data from both stimulus-driven and resting-state experimental conditions in visual cortex.

  16. Smile line assessment comparing quantitative measurement and visual estimation.

    Science.gov (United States)

    Van der Geld, Pieter; Oosterveld, Paul; Schols, Jan; Kuijpers-Jagtman, Anne Marie

    2011-02-01

    Esthetic analysis of dynamic functions such as spontaneous smiling is feasible by using digital videography and computer measurement for lip line height and tooth display. Because quantitative measurements are time-consuming, digital videography and semiquantitative (visual) estimation according to a standard categorization are more practical for regular diagnostics. Our objective in this study was to compare 2 semiquantitative methods with quantitative measurements for reliability and agreement. The faces of 122 male participants were individually registered by using digital videography. Spontaneous and posed smiles were captured. On the records, maxillary lip line heights and tooth display were digitally measured on each tooth and also visually estimated according to 3-grade and 4-grade scales. Two raters were involved. An error analysis was performed. Reliability was established with kappa statistics. Interexaminer and intraexaminer reliability values were high, with median kappa values from 0.79 to 0.88. Agreement of the 3-grade scale estimation with quantitative measurement showed higher median kappa values (0.76) than the 4-grade scale estimation (0.66). Differentiating high and gummy smile lines (4-grade scale) resulted in greater inaccuracies. The estimation of a high, average, or low smile line for each tooth showed high reliability close to quantitative measurements. Smile line analysis can be performed reliably with a 3-grade scale (visual) semiquantitative estimation. For a more comprehensive diagnosis, additional measuring is proposed, especially in patients with disproportional gingival display. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  17. Distributed Estimation, Coding, and Scheduling in Wireless Visual Sensor Networks

    Science.gov (United States)

    Yu, Chao

    2013-01-01

    In this thesis, we consider estimation, coding, and sensor scheduling for energy efficient operation of wireless visual sensor networks (VSN), which consist of battery-powered wireless sensors with sensing (imaging), computation, and communication capabilities. The competing requirements for applications of these wireless sensor networks (WSN)…

  18. 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 ...

  19. 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 ...

  20. 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 ...

  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 ... Catheter Angiography? Angiography is a minimally invasive medical test that helps physicians diagnose and treat medical conditions. ...

  2. Estimation of radiation exposure of different dose saving techniques in 128-slice computed tomography coronary angiography.

    Science.gov (United States)

    Ketelsen, Dominik; Fenchel, Michael; Buchgeister, Markus; Thomas, Christoph; Boehringer, Nadine; Tsiflikas, Ilias; Kaempf, Michael; Syha, Roland; Claussen, Claus D; Heuschmid, Martin

    2012-02-01

    To estimate the effective dose of cardiac CT with different dose saving strategies dependent on varying heart rates. For dose measurements, an Alderson-Rando-phantom equipped with thermoluminescent dosimeters was used. The effective dose was calculated according to ICRP 103. Exposure was performed on a 128-slice single source scanner providing a rotation time of 0.30s and standard protocols with 120 kV and 160 mAs/rot. Protocols were evaluated without ECG-pulsing, with two different ECG-pulsing techniques, and automated exposure control with a simulated heart rate of 60 and 100 beats per minute. Depending on different dose saving techniques and heart rate, the effective whole-body dose of a cardiac scan ranged from 2.8 to 9.5 mSv and from 4.3 to 16.0 mSv for males and females, respectively. The radiation-sensitive breast tissue in the primary scan range results in an increased female dose of 66.7 ± 6.0%. Prospective triggering has the greatest potential to reduce the effective dose to 27.8%, compared to a comparable scan protocol with retrospective ECG-triggering with no ECG-pulsing. Furthermore, the heart rate influences the radiation exposure by increasing significantly at lower heart rates. Due to this broad variability in radiation exposure of a cardiac CT, the radiologist and the CT technician should be aware of the different dose reduction strategies. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  3. Estimated radiation dose and image quality comparison of the scan protocols in dual-source computed tomography coronary angiography.

    Science.gov (United States)

    Karaarslan, Ercan; Ulus, Sıla; Bavbek, Cengiz

    2013-08-01

    Radiation exposure from computed tomography coronary angiography (CTCA) is of particular concern and several techniques have been introduced to lower the radiation dose. In this study, we aimed to compare the diagnostic image quality and estimated radiation dose of the three CTCA acquisition protocols in a recently introduced second generation dual-source computed tomography. Two hundred consecutive subjects underwent dual-source CTCA by using high-pitch spiral, sequential and retrospective spiral protocols. Effective radiation dose, expressed in millisieverts, was calculated as the product of the dose-length product times a conversion factor of 0.014. Image quality was evaluated on a per-segment basis, with a four-point scale. For the high-pitch spiral, sequential and retrospective spiral protocols, mean effective radiation doses were 1.41 ± 0.56, 5.50 ± 2.06 and 7.79 ± 2.25 mSv and mean per-subject image scores were 2.8 ± 0.7, 2.2 ± 0.8 and 2.5 ± 0.8, respectively. Radiation dose of the high-pitch mode was significantly lower (P quality revealed a significant difference between the high-pitch spiral and the sequential modes (P source CTCA using high-pitch acquisition considerably lowers radiation exposure in subjects with a low and stable heart rate and maintains good image quality, especially when the subjects have a body mass index ≤25 and a tube voltage of 80 or 100 kV is used. However, when sequential and retrospective spiral modes are used in the same device, mean radiation doses can increase roughly three and five times more, respectively. © 2013 The Authors. Journal of Medical Imaging and Radiation Oncology © 2013 The Royal Australian and New Zealand College of Radiologists.

  4. ESTIMATION OF CARDIAC CT ANGIOGRAPHY RADIATION DOSE TOWARD THE ESTABLISHMENT OF NATIONAL DIAGNOSTIC REFERENCE LEVEL FOR CCTA IN IRAN.

    Science.gov (United States)

    Hosseini Nasab, Seyed Mohammad Bagher; Shabestani-Monfared, Ali; Deevband, Mohammad Reza; Paydar, Reza; Nabahati, Mehrdad

    2017-05-01

    In recent years, with the introduction of 64-slice CT and dual-source CT technology, coronary CT angiography (CCTA) has emerged as a useful diagnostic imaging modality as a non-invasive assessment of coronary heart disease. CT produces a larger radiation dose than other imaging tests and cardiac CT involves higher radiation dose with the advances in the spatial and temporal resolution. The aims of this study are patient dose assessment and establishment of national diagnostic reference level for CCTA in Iran. A questionnaire was sent to CCTA centers. Data for patient and CT protocols were obtained. The volumetric CT dose index (CTDIvol), dose length product (DLP) and total DLP were considered in the 32 cm standard body phantom. Calculation of estimated effective dose (ED) was obtained by multiplying the DLP by a conversion factor [k = 0.014 mSv (mGy·cm)-1]. Mean value of CTDIvol and DLP for CCTA was 50 mGy and 825 mGy·cm. The third quartile (75th) of the distribution of mean CTDIvol (66.54 mGy) and DLP (1073 mGy·cm) values was expressed as the diagnostic reference level (DRL) for CCTA in Iran. The median of ED was 10.26 mSv and interquartile range of ED was 7.08-15.03 mSv. A large variety in CTDIvol and DLP among CT scanner and different sites due to variability in CT parameter is noted. It seems that training could help to reduce patient's dose. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Numerosity estimates for attended and unattended items in visual search.

    Science.gov (United States)

    Kelley, Troy D; Cassenti, Daniel N; Marusich, Laura R; Ghirardelli, Thomas G

    2017-07-01

    The goal of this research was to examine memories created for the number of items during a visual search task. Participants performed a visual search task for a target defined by a single feature (Experiment 1A), by a conjunction of features (Experiment 1B), or by a specific spatial configuration of features (Experiment 1C). On some trials following the search task, subjects were asked to recall the total number of items in the previous display. In all search types, participants underestimated the total number of items, but the severity of the underestimation varied depending on the efficiency of the search. In three follow-up studies (Experiments 2A, 2B, and 2C) using the same visual stimuli, the participants' only task was to estimate the number of items on each screen. Participants still underestimated the numerosity of the items, although the degree of underestimation was smaller than in the search tasks and did not depend on the type of visual stimuli. In Experiment 3, participants were asked to recall the number of items in a display only once. Subjects still displayed a tendency to underestimate, indicating that the underestimation effects seen in Experiments 1A-1C were not attributable to knowledge of the estimation task. The degree of underestimation depends on the efficiency of the search task, with more severe underestimation in efficient search tasks. This suggests that the lower attentional demands of very efficient searches leads to less encoding of numerosity of the distractor set.

  6. 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 ...

  7. 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 ...

  8. 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 ...

  9. 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 ...

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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, ...

  11. 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 ...

  12. 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 ...

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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 ...

  14. 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 ...

  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 ... are a form of radiation like light or radio waves. X-rays pass through most objects, including ...

  16. 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 ...

  17. 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 ...

  18. 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 ...

  19. 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 ...

  20. 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 ...

  1. 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 ...

  2. 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 ...

  3. 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 ( ...

  4. Catheter Angiography

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  5. 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 ...

  6. Catheter Angiography

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  7. 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 ...

  8. 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 ...

  9. 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 ...

  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 ... in key areas of the body, including the: brain neck heart chest abdomen (such as the kidneys ...

  11. 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 ...

  12. 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 ...

  13. Estimation of radiation exposure of retrospective gated and prospective triggered 128-slice triple-rule-out CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Ketelsen, Dominik; Fenchel, Michael; Thomas, Christoph; Boehringer, Nadine; Tsiflikas, Ilias; Kaempf, Michael; Claussen, Claus D; Heuschmid, Martin (Dept. of Diagnostic and Interventional Radiology, Univ. Hospital Tuebingen, Tuebingen (Germany)), email: dominik.ketelsen@med.uni-tuebingen.de; Buchgeister, Markus (Depts. of Radiotherapy and Radiooncology, Univ. Hospital Tuebingen, Tuebingen (Germany))

    2011-09-15

    Background: CT has become an important role in the differential diagnosis of acute chest pain to exclude an aortic dissection, pulmonary embolism and acute coronary artery syndrome. However, the additional radiation exposure is a cause of concern and dose saving strategies should be applied, if possible. Purpose: To estimate effective dose of retrospective gated and prospective ECG-triggered triple-rule-out computed tomography angiography (TRO-CTA). Material and Methods: An Alderson-Rando-phantom equipped with thermoluminescent dosimeters was used for dose measurements. Exposure was performed on a 128-slice single source scanner. The following scan parameters were used (retrospective ECG-gated): 120 kV, 190 mAs/rot., collimation 128x0.6 mm, rotation time 0.3 s. Protocols with a simulated heart rate (HR) of 60 and 100 bpm were performed using the standard ECG-pulsing as well as MinDose. Additionally, a prospective triggered TRO-CTA was acquired (HR 60 bpm). Results: The estimated effective dose of retrospective ECG-gated TRO-CTA ranged from 7.4-13.4 mSv and from 10.1-17.5 mSv for men and women, respectively. Due to radiosensitive breast tissue, women received a significant increased effective dose of up to 64.7% +- 0.03% (p = 0.028) compared to men. MinDose reduces radiation exposure of up to 33.0% +- 6.5% in comparison to standard ECG-pulsing (p < 0.001). The effective dose increased significantly with lower heart rates (p < 0.001). Prospective ECG-triggered TRO-CTA showed an effective dose of 5.9 mSv and 8.2 mSv for men and women, respectively. Compared to retrospective ECG-gated TRO-CTA a significant dose reduction was observed (p < 0.001). Conclusion: Due to the significant different dose exposure, scan protocols should be specifically adapted in a patient- and problem-oriented manner

  14. A database for estimating organ dose for coronary angiography and brain perfusion CT scans for arbitrary spectra and angular tube current modulation

    Energy Technology Data Exchange (ETDEWEB)

    Rupcich, Franco; Badal, Andreu; Kyprianou, Iacovos; Schmidt, Taly Gilat [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States); Division of Imaging and Applied Mathematics (OSEL/CDRH), US Food and Drug Administration, Silver Spring, Maryland 20905 (United States); Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States)

    2012-09-15

    Purpose: The purpose of this study was to develop a database for estimating organ dose in a voxelized patient model for coronary angiography and brain perfusion CT acquisitions with any spectra and angular tube current modulation setting. The database enables organ dose estimation for existing and novel acquisition techniques without requiring Monte Carlo simulations. Methods: The study simulated transport of monoenergetic photons between 5 and 150 keV for 1000 projections over 360 Degree-Sign through anthropomorphic voxelized female chest and head (0 Degree-Sign and 30 Degree-Sign tilt) phantoms and standard head and body CTDI dosimetry cylinders. The simulations resulted in tables of normalized dose deposition for several radiosensitive organs quantifying the organ dose per emitted photon for each incident photon energy and projection angle for coronary angiography and brain perfusion acquisitions. The values in a table can be multiplied by an incident spectrum and number of photons at each projection angle and then summed across all energies and angles to estimate total organ dose. Scanner-specific organ dose may be approximated by normalizing the database-estimated organ dose by the database-estimated CTDI{sub vol} and multiplying by a physical CTDI{sub vol} measurement. Two examples are provided demonstrating how to use the tables to estimate relative organ dose. In the first, the change in breast and lung dose during coronary angiography CT scans is calculated for reduced kVp, angular tube current modulation, and partial angle scanning protocols relative to a reference protocol. In the second example, the change in dose to the eye lens is calculated for a brain perfusion CT acquisition in which the gantry is tilted 30 Degree-Sign relative to a nontilted scan. Results: Our database provides tables of normalized dose deposition for several radiosensitive organs irradiated during coronary angiography and brain perfusion CT scans. Validation results indicate

  15. A database for estimating organ dose for coronary angiography and brain perfusion CT scans for arbitrary spectra and angular tube current modulation.

    Science.gov (United States)

    Rupcich, Franco; Badal, Andreu; Kyprianou, Iacovos; Schmidt, Taly Gilat

    2012-09-01

    The purpose of this study was to develop a database for estimating organ dose in a voxelized patient model for coronary angiography and brain perfusion CT acquisitions with any spectra and angular tube current modulation setting. The database enables organ dose estimation for existing and novel acquisition techniques without requiring Monte Carlo simulations. The study simulated transport of monoenergetic photons between 5 and 150 keV for 1000 projections over 360° through anthropomorphic voxelized female chest and head (0° and 30° tilt) phantoms and standard head and body CTDI dosimetry cylinders. The simulations resulted in tables of normalized dose deposition for several radiosensitive organs quantifying the organ dose per emitted photon for each incident photon energy and projection angle for coronary angiography and brain perfusion acquisitions. The values in a table can be multiplied by an incident spectrum and number of photons at each projection angle and then summed across all energies and angles to estimate total organ dose. Scanner-specific organ dose may be approximated by normalizing the database-estimated organ dose by the database-estimated CTDI(vol) and multiplying by a physical CTDI(vol) measurement. Two examples are provided demonstrating how to use the tables to estimate relative organ dose. In the first, the change in breast and lung dose during coronary angiography CT scans is calculated for reduced kVp, angular tube current modulation, and partial angle scanning protocols relative to a reference protocol. In the second example, the change in dose to the eye lens is calculated for a brain perfusion CT acquisition in which the gantry is tilted 30° relative to a nontilted scan. Our database provides tables of normalized dose deposition for several radiosensitive organs irradiated during coronary angiography and brain perfusion CT scans. Validation results indicate total organ doses calculated using our database are within 1% of those

  16. A database for estimating organ dose for coronary angiography and brain perfusion CT scans for arbitrary spectra and angular tube current modulation

    International Nuclear Information System (INIS)

    Rupcich, Franco; Badal, Andreu; Kyprianou, Iacovos; Schmidt, Taly Gilat

    2012-01-01

    Purpose: The purpose of this study was to develop a database for estimating organ dose in a voxelized patient model for coronary angiography and brain perfusion CT acquisitions with any spectra and angular tube current modulation setting. The database enables organ dose estimation for existing and novel acquisition techniques without requiring Monte Carlo simulations. Methods: The study simulated transport of monoenergetic photons between 5 and 150 keV for 1000 projections over 360° through anthropomorphic voxelized female chest and head (0° and 30° tilt) phantoms and standard head and body CTDI dosimetry cylinders. The simulations resulted in tables of normalized dose deposition for several radiosensitive organs quantifying the organ dose per emitted photon for each incident photon energy and projection angle for coronary angiography and brain perfusion acquisitions. The values in a table can be multiplied by an incident spectrum and number of photons at each projection angle and then summed across all energies and angles to estimate total organ dose. Scanner-specific organ dose may be approximated by normalizing the database-estimated organ dose by the database-estimated CTDI vol and multiplying by a physical CTDI vol measurement. Two examples are provided demonstrating how to use the tables to estimate relative organ dose. In the first, the change in breast and lung dose during coronary angiography CT scans is calculated for reduced kVp, angular tube current modulation, and partial angle scanning protocols relative to a reference protocol. In the second example, the change in dose to the eye lens is calculated for a brain perfusion CT acquisition in which the gantry is tilted 30° relative to a nontilted scan. Results: Our database provides tables of normalized dose deposition for several radiosensitive organs irradiated during coronary angiography and brain perfusion CT scans. Validation results indicate total organ doses calculated using our database are

  17. Quantitative coronary angiography in the estimation of the functional significance of coronary stenosis: correlations with dobutamine-atropine stress test

    NARCIS (Netherlands)

    J.M.P. Baptista da Silva (José); M. Arnese (Mariarosaria); J.R.T.C. Roelandt (Jos); P.M. Fioretti (Paolo); D.T.J. Keane (David); J. Escaned (Javier); C. di Mario (Carlo); P.W.J.C. Serruys (Patrick); H. Boersma (Eric)

    1994-01-01

    textabstractOBJECTIVES. The purpose of this study was to determine the predictive value of quantitative coronary angiography in the assessment of the functional significance of coronary stenosis as judged from the development of left ventricular wall motion abnormalities during dobutamine-atropine

  18. Visualization of RELAP5-3D best estimate code

    International Nuclear Information System (INIS)

    Mesina, G.L.

    2004-01-01

    The Idaho National Engineering Laboratory has developed a number of nuclear plant analysis codes such as RELAP5-3D, SCDAP/RELAP5-3D, and FLUENT/RELAP5-3D that have multi-dimensional modeling capability. The output of these codes is very difficult to analyze without the aid of visualization tools. The RELAP5-3D Graphical User Interface (RGUI) displays these calculations on plant images, functional diagrams, graphs, and by other means. These representations of the data enhance the analysts' ability to recognize plant behavior visually and reduce the difficulty of analyzing complex three-dimensional models. This paper describes the Graphical User Interface system for the RELAP5-3D suite of Best Estimate codes. The uses of the Graphical User Interface are illustrated. Examples of user problems solved by use of this interface are given. (author)

  19. Clinical study on relationship of visualization of the cerebral arteries in MR angiography to age, sex, laterality or lacunar infarction in neurologically normal subjects

    International Nuclear Information System (INIS)

    Kajiya, Yoriko

    1995-01-01

    The purpose of this study is to assess the correlation between the visualization of cerebral peripheral arteries in magnetic resonance angiography (MRA) and aging, sex, laterality or lacunar infarctions in magnetic resonance imaging (MRI). Two hundred forty-four neurologically normal subjects (119 males and 125 females, aged 7 to 82 yrs.) were evaluated with MRA and MRI. A three-dimensional Fourier transformation (3DFT-TOF) pulse sequence with slab thickness of 115 mm was used to obtain axial, sagittal and coronal projection images. The imaging parameters were 30/11/1 (TR/TE/excitations) using a 20 degree flip angle and the voxel size was 0.9 x 1.1 x 0.9 mm. A total of 6 arteries including bilateral anterior cerebral arteries (ACAs), middle cerebral arteries (MCAs) and posterior cerebral arteries (PCAs) for every subject were each graded into 8 scores by the degree of visualization of the arteries. Asymptomatic lacunar infarctions were analyzed in subjects of fifties or more. They were scored as 0-2 based on their size and the scores were summed. An age-related decline of visualization of the cerebral arteries was observed in ACA (r=-0.603, p<0.001), MCA (r=-0.452, p<0.001) and PCA (r=-0.537, p<0.001). Females during the fifth decade had a higher score of visualization of the arteries than males (p<0.01). No substantial relationship was observed between visualization of the arteries and sex in other decades, laterality or lacunar infarctions. The MRA using a 3DFT-TOF pulse sequence with slab thickness of 115 mm disclosed an age-related decline of visualization of the cerebral arteries and a sex-dependent difference of the visualization in the fifth decade probably due to the decline of the blood flow velocity with aging and a difference in it between females and males in the fifth decade, respectively. (J.P.N.)

  20. Clinical study on relationship of visualization of the cerebral arteries in MR angiography to age, sex, laterality or lacunar infarction in neurologically normal subjects

    Energy Technology Data Exchange (ETDEWEB)

    Kajiya, Yoriko [Kagoshima Univ. (Japan). Faculty of Medicine

    1995-08-01

    The purpose of this study is to assess the correlation between the visualization of cerebral peripheral arteries in magnetic resonance angiography (MRA) and aging, sex, laterality or lacunar infarctions in magnetic resonance imaging (MRI). Two hundred forty-four neurologically normal subjects (119 males and 125 females, aged 7 to 82 yrs.) were evaluated with MRA and MRI. A three-dimensional Fourier transformation (3DFT-TOF) pulse sequence with slab thickness of 115 mm was used to obtain axial, sagittal and coronal projection images. The imaging parameters were 30/11/1 (TR/TE/excitations) using a 20 degree flip angle and the voxel size was 0.9 x 1.1 x 0.9 mm. A total of 6 arteries including bilateral anterior cerebral arteries (ACAs), middle cerebral arteries (MCAs) and posterior cerebral arteries (PCAs) for every subject were each graded into 8 scores by the degree of visualization of the arteries. Asymptomatic lacunar infarctions were analyzed in subjects of fifties or more. They were scored as 0-2 based on their size and the scores were summed. An age-related decline of visualization of the cerebral arteries was observed in ACA (r=-0.603, p<0.001), MCA (r=-0.452, p<0.001) and PCA (r=-0.537, p<0.001). Females during the fifth decade had a higher score of visualization of the arteries than males (p<0.01). No substantial relationship was observed between visualization of the arteries and sex in other decades, laterality or lacunar infarctions. The MRA using a 3DFT-TOF pulse sequence with slab thickness of 115 mm disclosed an age-related decline of visualization of the cerebral arteries and a sex-dependent difference of the visualization in the fifth decade probably due to the decline of the blood flow velocity with aging and a difference in it between females and males in the fifth decade, respectively. (J.P.N.).

  1. 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 produces very ... of a catheter makes it possible to combine diagnosis and treatment in a single procedure. An example is finding ...

  2. Catheter Angiography

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    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 ...

  3. 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 ...

  4. 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 regular x-ray ... any possibility that they are pregnant. See the Safety page for more information about pregnancy and x- ...

  5. Catheter Angiography

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    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 ( ...

  6. Transcranial Doppler US as an alternative to angiography and balloon occlusion in estimating risk of carotid occlusion

    International Nuclear Information System (INIS)

    Feaster, S.H.; Powers, A.; Laws, E.R.

    1990-01-01

    This paper demonstrates the reliability of transcranial Doppler (TCD) US in the evaluation of the adequacy of collateral vessel cerebral blood flow in patients being considered for carotid ligation or occlusion. TCD was utilized in 12 patients in an attempt to study collateral vessel blood flow during endovascular balloon occlusion of a carotid artery. This was correlated with TCD measurements performed during manual carotid compression and with cerebral angiography. Changes of blood flow velocity were measured in the ipsilateral MCA and ACA. Excellent correlation was noted between the TCD measurements during manual carotid compression and actual endovascular balloon occlusion. There was also qualitative agreement with the cross-compression angiogram

  7. Comparison of fluoro and cine coronary angiography: balancing acceptable outcomes with a reduction in radiation dose.

    Science.gov (United States)

    Olcay, Ayhan; Guler, Ekrem; Karaca, Ibrahim Oguz; Omaygenc, Mehmet Onur; Kizilirmak, Filiz; Olgun, Erkam; Yenipinar, Esra; Cakmak, Huseyin Altug; Duman, Dursun

    2015-04-01

    Use of last fluoro hold (LFH) mode in fluoroscopy, which enables the last live image to be saved and displayed, could reduce radiation during percutaneous coronary intervention when compared with cine mode. No previous study compared coronary angiography radiation doses and image quality between LFH and conventional cine mode techniques. We compared cumulative dose-area product (DAP), cumulative air kerma, fluoroscopy time, contrast use, interobserver variability of visual assessment between LFH angiography, and conventional cine angiography techniques. Forty-six patients were prospectively enrolled into the LFH group and 82 patients into the cine angiography group according to operator decision. Mean cumulative DAP was higher in the cine group vs the LFH group (50058.98 ± 53542.71 mGy•cm² vs 11349.2 ± 8796.46 mGy•cm²; Pcine group vs the LFH group (3.87 ± 5.08 minutes vs 1.66 ± 1.51 minutes; Pcine group vs the LFH group (112.07 ± 43.79 cc vs 88.15 ± 23.84 cc; Pcine and LFH angiography groups (0.66680 ± 0.19309 vs 0.54193 ± 0.31046; P=.20). Radiation doses, contrast use, and fluoroscopy times are lower in fluoroscopic LFH angiography vs cine angiography. Interclass variability of visual stenosis estimation between three operators was not different between cine and LFH groups. Fluoroscopic LFH images conventionally have inferior diagnostic quality when compared with cine coronary angiography, but with new angiographic systems with improved LFH image quality, these images may be adequate for diagnostic coronary angiography.

  8. Stent sizing strategies in renal artery stenting: the comparison of conventional invasive renal angiography with renal computed tomographic angiography

    Directory of Open Access Journals (Sweden)

    Jacek Kadziela

    2016-05-01

    Full Text Available Introduction : Randomized trials comparing invasive treatment of renal artery stenosis with standard pharmacotherapy did not show substantial benefit from revascularization. One of the potential reasons for that may be suboptimal procedure technique. Aim : To compare renal stent sizing using two modalities: three-dimensional renal computed tomography angiography (CTA versus conventional angiography. Material and methods: Forty patients (41 renal arteries, aged 65.1 ±8.5 years, who underwent renal artery stenting with preprocedural CTA performed within 6 months, were retrospectively analyzed. In CTA analysis, reference diameter (CTA-D and lesion length (CTA_LL were measured and proposed stent diameter and length were recorded. Similarly, angiographic reference diameter (ANGIO_D and lesion length (ANGIO_LL as well as proposed stent dimensions were obtained by visual estimation. Results: The median CTA_D was 0.5 mm larger than the median ANGIO_D (p < 0.001. Also, the proposed stent diameter in CTA evaluation was 0.5 mm larger than that in angiography (p < 0.0001. The median CTA_LL was 1 mm longer than the ANGIO_LL (p = NS, with significant correlation of these variables (r = 0.66, p < 0.0001. The median proposed stent length with CTA was equal to that proposed with angiography. The median diameter of the implanted stent was 0.5 mm smaller than that proposed in CTA (p < 0.0005 and identical to that proposed in angiography. The median length of the actual stent was longer than that proposed in angiography (p = 0.0001. Conclusions : Renal CTA has potential advantages as a tool adjunctive to angiography in appropriate stent sizing. Careful evaluation of the available CTA scans may be beneficial and should be considered prior to the planned procedure.

  9. Stent sizing strategies in renal artery stenting: the comparison of conventional invasive renal angiography with renal computed tomographic angiography.

    Science.gov (United States)

    Kadziela, Jacek; Michalowska, Ilona; Pregowski, Jerzy; Janaszek-Sitkowska, Hanna; Lech, Katarzyna; Kabat, Marek; Staruch, Adam; Januszewicz, Andrzej; Witkowski, Adam

    2016-01-01

    Randomized trials comparing invasive treatment of renal artery stenosis with standard pharmacotherapy did not show substantial benefit from revascularization. One of the potential reasons for that may be suboptimal procedure technique. To compare renal stent sizing using two modalities: three-dimensional renal computed tomography angiography (CTA) versus conventional angiography. Forty patients (41 renal arteries), aged 65.1 ±8.5 years, who underwent renal artery stenting with preprocedural CTA performed within 6 months, were retrospectively analyzed. In CTA analysis, reference diameter (CTA-D) and lesion length (CTA_LL) were measured and proposed stent diameter and length were recorded. Similarly, angiographic reference diameter (ANGIO_D) and lesion length (ANGIO_LL) as well as proposed stent dimensions were obtained by visual estimation. The median CTA_D was 0.5 mm larger than the median ANGIO_D (p < 0.001). Also, the proposed stent diameter in CTA evaluation was 0.5 mm larger than that in angiography (p < 0.0001). The median CTA_LL was 1 mm longer than the ANGIO_LL (p = NS), with significant correlation of these variables (r = 0.66, p < 0.0001). The median proposed stent length with CTA was equal to that proposed with angiography. The median diameter of the implanted stent was 0.5 mm smaller than that proposed in CTA (p < 0.0005) and identical to that proposed in angiography. The median length of the actual stent was longer than that proposed in angiography (p = 0.0001). Renal CTA has potential advantages as a tool adjunctive to angiography in appropriate stent sizing. Careful evaluation of the available CTA scans may be beneficial and should be considered prior to the planned procedure.

  10. 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.

  11. Estimation of loneliness in students with visual impairments

    Directory of Open Access Journals (Sweden)

    Stanimirović Dragana V.

    2017-01-01

    Full Text Available Background/Aim. Loneliness is becoming more frequent, especially in young people. Some authors believe that visual impairments increase the risk of loneliness. Empirical data on its manifestation in persons with visual impairments are contradictory. The aim of this research was to determine the degree of loneliness in students with visual impairments and their peers from general population. Methods. A comparative research was conducted on a sample consisting of 36 visually impaired students and 101 students without visual impairments (control group. Students with visual impairments were divided into 3 subgroups with regard to the degree of visual impairments (students with low vision, legally blind, and totally blind students. University of California Los Angeles Loneliness Scale (which assesses the general loneliness and Social and Emotional Loneliness Scale (which assesses social loneliness, family loneliness, and romantic loneliness were used in our investigation. Results. The results showed that the general loneliness was significantly lower in the group of students with visual impairments than in the control group (t = 2.121; p = 0.036. There were no significant differences in the Social and Emotional Loneliness Scale between the group with visual impairments and the control group. No significant differences were determined in the level of loneliness among students with a different degree of visual impairments. There are significant differences in the manifestation level of social loneliness, family loneliness, and romantic loneliness (Wilk’s lambda = 0.604; p ≤ 0.000 in the group of students with visual impairments. Romantic loneliness was manifested the most, followed by social loneliness, while family loneliness was the least manifested. Conclusion. With regard to the results of our research, visual impairment alone is not a crucial factor of loneliness in students with visual impairments. Further studies on protective factors of

  12. Transluminal color-coded three-dimensional magnetic resonance angiography for visualization of signal Intensity distribution pattern within an unruptured cerebral aneurysm: preliminarily assessment with anterior communicating artery aneurysms

    International Nuclear Information System (INIS)

    Satoh, T.; Ekino, C.; Ohsako, C.

    2004-01-01

    The natural history of unruptured cerebral aneurysm is not known; also unknown is the potential growth and rupture in any individual aneurysm. The authors have developed transluminal color-coded three-dimensional magnetic resonance angiography (MRA) obtained by a time-of-flight sequence to investigate the interaction between the intra-aneurysmal signal intensity distribution patterns and configuration of unruptured cerebral aneurysms. Transluminal color-coded images were reconstructed from volume data of source magnetic resonance angiography by using a parallel volume-rendering algorithm with transluminal imaging technique. By selecting a numerical threshold range from a signal intensity opacity chart of the three-dimensional volume-rendering dataset several areas of signal intensity were depicted, assigned different colors, and visualized transparently through the walls of parent arteries and an aneurysm. Patterns of signal intensity distribution were analyzed with three operated cases of an unruptured anterior communicating artery aneurysm and compared with the actual configurations observed at microneurosurgery. A little difference in marginal features of an aneurysm was observed; however, transluminal color-coded images visualized the complex signal intensity distribution within an aneurysm in conjunction with aneurysmal geometry. Transluminal color-coded three-dimensional magnetic resonance angiography can thus provide numerical analysis of the interaction between spatial signal intensity distribution patterns and aneurysmal configurations and may offer an alternative and practical method to investigate the patient-specific natural history of individual unruptured cerebral aneurysms. (orig.)

  13. Probabilistic Mapping of Human Visual Attention from Head Pose Estimation

    Directory of Open Access Journals (Sweden)

    Andrea Veronese

    2017-10-01

    Full Text Available Effective interaction between a human and a robot requires the bidirectional perception and interpretation of actions and behavior. While actions can be identified as a directly observable activity, this might not be sufficient to deduce actions in a scene. For example, orienting our face toward a book might suggest the action toward “reading.” For a human observer, this deduction requires the direction of gaze, the object identified as a book and the intersection between gaze and book. With this in mind, we aim to estimate and map human visual attention as directed to a scene, and assess how this relates to the detection of objects and their related actions. In particular, we consider human head pose as measurement to infer the attention of a human engaged in a task and study which prior knowledge should be included in such a detection system. In a user study, we show the successful detection of attention to objects in a typical office task scenario (i.e., reading, working with a computer, studying an object. Our system requires a single external RGB camera for head pose measurements and a pre-recorded 3D point cloud of the environment.

  14. 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

  15. Comparison of visual acuity estimates using three different letter charts under two ambient room illuminations

    OpenAIRE

    Chen, Ai-Hong; Norazman, Fatin Nur Najwa; Buari, Noor Halilah

    2012-01-01

    Background: Visual acuity is an essential estimate to assess ability of the visual system and is used as an indicator of ocular health status. Aim: The aim of this study is to investigate the consistency of acuity estimates from three different clinical visual acuity charts under two levels of ambient room illumination. Materials and Methods: This study involved thirty Malay university students aged between 19 and 23 years old (7 males, 23 females), with their spherical refractive error rangi...

  16. Automated volumetric breast density estimation: A comparison with visual assessment

    International Nuclear Information System (INIS)

    Seo, J.M.; Ko, E.S.; Han, B.-K.; Ko, E.Y.; Shin, J.H.; Hahn, S.Y.

    2013-01-01

    Aim: To compare automated volumetric breast density (VBD) measurement with visual assessment according to Breast Imaging Reporting and Data System (BI-RADS), and to determine the factors influencing the agreement between them. Materials and methods: One hundred and ninety-three consecutive screening mammograms reported as negative were included in the study. Three radiologists assigned qualitative BI-RADS density categories to the mammograms. An automated volumetric breast-density method was used to measure VBD (% breast density) and density grade (VDG). Each case was classified into an agreement or disagreement group according to the comparison between visual assessment and VDG. The correlation between visual assessment and VDG was obtained. Various physical factors were compared between the two groups. Results: Agreement between visual assessment by the radiologists and VDG was good (ICC value = 0.757). VBD showed a highly significant positive correlation with visual assessment (Spearman's ρ = 0.754, p < 0.001). VBD and the x-ray tube target was significantly different between the agreement group and the disagreement groups (p = 0.02 and 0.04, respectively). Conclusion: Automated VBD is a reliable objective method to measure breast density. The agreement between VDG and visual assessment by radiologist might be influenced by physical factors

  17. Tensor Completion for Estimating Missing Values in Visual Data

    KAUST Repository

    Liu, Ji

    2012-01-25

    In this paper, we propose an algorithm to estimate missing values in tensors of visual data. The values can be missing due to problems in the acquisition process or because the user manually identified unwanted outliers. Our algorithm works even with a small amount of samples and it can propagate structure to fill larger missing regions. Our methodology is built on recent studies about matrix completion using the matrix trace norm. The contribution of our paper is to extend the matrix case to the tensor case by proposing the first definition of the trace norm for tensors and then by building a working algorithm. First, we propose a definition for the tensor trace norm that generalizes the established definition of the matrix trace norm. Second, similarly to matrix completion, the tensor completion is formulated as a convex optimization problem. Unfortunately, the straightforward problem extension is significantly harder to solve than the matrix case because of the dependency among multiple constraints. To tackle this problem, we developed three algorithms: simple low rank tensor completion (SiLRTC), fast low rank tensor completion (FaLRTC), and high accuracy low rank tensor completion (HaLRTC). The SiLRTC algorithm is simple to implement and employs a relaxation technique to separate the dependant relationships and uses the block coordinate descent (BCD) method to achieve a globally optimal solution; the FaLRTC algorithm utilizes a smoothing scheme to transform the original nonsmooth problem into a smooth one and can be used to solve a general tensor trace norm minimization problem; the HaLRTC algorithm applies the alternating direction method of multipliers (ADMMs) to our problem. Our experiments show potential applications of our algorithms and the quantitative evaluation indicates that our methods are more accurate and robust than heuristic approaches. The efficiency comparison indicates that FaLTRC and HaLRTC are more efficient than SiLRTC and between Fa

  18. Merging Psychophysical and Psychometric Theory to Estimate Global Visual State Measures from Forced-Choices

    International Nuclear Information System (INIS)

    Massof, Robert W; Schmidt, Karen M; Laby, Daniel M; Kirschen, David; Meadows, David

    2013-01-01

    Visual acuity, a forced-choice psychophysical measure of visual spatial resolution, is the sine qua non of clinical visual impairment testing in ophthalmology and optometry patients with visual system disorders ranging from refractive error to retinal, optic nerve, or central visual system pathology. Visual acuity measures are standardized against a norm, but it is well known that visual acuity depends on a variety of stimulus parameters, including contrast and exposure duration. This paper asks if it is possible to estimate a single global visual state measure from visual acuity measures as a function of stimulus parameters that can represent the patient's overall visual health state with a single variable. Psychophysical theory (at the sensory level) and psychometric theory (at the decision level) are merged to identify the conditions that must be satisfied to derive a global visual state measure from parameterised visual acuity measures. A global visual state measurement model is developed and tested with forced-choice visual acuity measures from 116 subjects with no visual impairments and 560 subjects with uncorrected refractive error. The results are in agreement with the expectations of the model

  19. Merging Psychophysical and Psychometric Theory to Estimate Global Visual State Measures from Forced-Choices

    Science.gov (United States)

    Massof, Robert W.; Schmidt, Karen M.; Laby, Daniel M.; Kirschen, David; Meadows, David

    2013-09-01

    Visual acuity, a forced-choice psychophysical measure of visual spatial resolution, is the sine qua non of clinical visual impairment testing in ophthalmology and optometry patients with visual system disorders ranging from refractive error to retinal, optic nerve, or central visual system pathology. Visual acuity measures are standardized against a norm, but it is well known that visual acuity depends on a variety of stimulus parameters, including contrast and exposure duration. This paper asks if it is possible to estimate a single global visual state measure from visual acuity measures as a function of stimulus parameters that can represent the patient's overall visual health state with a single variable. Psychophysical theory (at the sensory level) and psychometric theory (at the decision level) are merged to identify the conditions that must be satisfied to derive a global visual state measure from parameterised visual acuity measures. A global visual state measurement model is developed and tested with forced-choice visual acuity measures from 116 subjects with no visual impairments and 560 subjects with uncorrected refractive error. The results are in agreement with the expectations of the model.

  20. Catheter Angiography

    Medline Plus

    Full Text Available ... artery of the neck, which may limit blood flow to the brain and cause a stroke. identify ... the arteries to the kidneys or visualize blood flow to help prepare for a kidney transplant or ...

  1. 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

  2. Visual odometry for trailer off-tracking estimation

    CSIR Research Space (South Africa)

    De Saxe, Christopher

    2016-11-01

    Full Text Available that that existing methods for this are not applicable on roads with low friction or significant camber or grade. Here we propose an off-tracking measurement concept using stereo visual odometry which is applicable to off-highway environments. Simulation results...

  3. 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.)

  4. Inter-observer variation in estimates by nuclear angiography of left ventricular ejection fraction and ejection rate

    International Nuclear Information System (INIS)

    Young, K.C.; Railton, R.

    1980-01-01

    The recent decline in the cost of computing has led to the introduction of data processing of gamma-camera images in many medical centres, allowing the development and widespread use of radionuclide techniques for assessing left ventricular performance. Methods such as ECG-gated blood-pool imaging have the advantage of being less invasive than contrast ventriculography and do not rely on geometrical assumptions about the shape of the ventricle. A study has been made of the inter-observer variation in estimates of ejection fraction and average and maximum systolic contraction rates using a micro-computer (VIP-450 Video Image Processor, Ohio-Nuclear Limited, Rugby) to analyse gated blood-pool images of the left ventricle. (author)

  5. Left Gastric Vein Visualization with Hepatopetal Flow Information in Healthy Subjects Using Non-Contrast-Enhanced Magnetic Resonance Angiography with Balanced Steady-State Free-Precession Sequence and Time-Spatial Labeling Inversion Pulse.

    Science.gov (United States)

    Furuta, Akihiro; Isoda, Hiroyoshi; Ohno, Tsuyoshi; Ono, Ayako; Yamashita, Rikiya; Arizono, Shigeki; Kido, Aki; Sakashita, Naotaka; Togashi, Kaori

    2018-01-01

    To selectively visualize the left gastric vein (LGV) with hepatopetal flow information by non-contrast-enhanced magnetic resonance angiography under a hypothesis that change in the LGV flow direction can predict the development of esophageal varices; and to optimize the acquisition protocol in healthy subjects. Respiratory-gated three-dimensional balanced steady-state free-precession scans were conducted on 31 healthy subjects using two methods (A and B) for visualizing the LGV with hepatopetal flow. In method A, two time-spatial labeling inversion pulses (Time-SLIP) were placed on the whole abdomen and the area from the gastric fornix to the upper body, excluding the LGV area. In method B, nonselective inversion recovery pulse was used and one Time-SLIP was placed on the esophagogastric junction. The detectability and consistency of LGV were evaluated using the two methods and ultrasonography (US). Left gastric veins by method A, B, and US were detected in 30 (97%), 24 (77%), and 23 (74%) subjects, respectively. LGV flow by US was hepatopetal in 22 subjects and stagnant in one subject. All hepatopetal LGVs by US coincided with the visualized vessels in both methods. One subject with non-visualized LGV in method A showed stagnant LGV by US. Hepatopetal LGV could be selectively visualized by method A in healthy subjects.

  6. Robust Visual Tracking Using the Bidirectional Scale Estimation

    Directory of Open Access Journals (Sweden)

    An Zhiyong

    2017-01-01

    Full Text Available Object tracking with robust scale estimation is a challenging task in computer vision. This paper presents a novel tracking algorithm that learns the translation and scale filters with a complementary scheme. The translation filter is constructed using the ridge regression and multidimensional features. A robust scale filter is constructed by the bidirectional scale estimation, including the forward scale and backward scale. Firstly, we learn the scale filter using the forward tracking information. Then the forward scale and backward scale can be estimated using the respective scale filter. Secondly, a conservative strategy is adopted to compromise the forward and backward scales. Finally, the scale filter is updated based on the final scale estimation. It is effective to update scale filter since the stable scale estimation can improve the performance of scale filter. To reveal the effectiveness of our tracker, experiments are performed on 32 sequences with significant scale variation and on the benchmark dataset with 50 challenging videos. Our results show that the proposed tracker outperforms several state-of-the-art trackers in terms of robustness and accuracy.

  7. Estimating Field Densities of Haematobia irritans (Diptera: Muscidae) Using Direct Visual Field Counts Versus Photographic Assessments.

    Science.gov (United States)

    Mullens, Bradley A; Soto, Diane; Gerry, Alec C

    2016-05-01

    Horn flies, Haematobia irritans (L.), were photographed on cattle and then immediately estimated visually in the field on pastured beef cattle in southern California. Horn flies were counted in the pictures later on a computer screen. For 479 counts on individual cattle, the concordance correlation coefficient between the visual and photo-based assessments was 0.790, but was better for the higher half of the counts (0.732) than for the lower half of the counts (0.217). Major axis regression indicated that visual estimates were consistently higher than the number of flies counted in the pictures across the entire density range. Based on average raw means, the visual estimates averaged 21% higher than the photo counts. Visual estimates included flies on the belly and lower legs that could not be seen in a photo, and lower densities may have been more susceptible to such error. Where flies can be seen well, e.g. for very tame animals, the visual estimates were much faster and more cost-efficient and were sufficient to track relative horn fly abundance changes. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. A simple visual estimation of food consumption in carnivores.

    Directory of Open Access Journals (Sweden)

    Katherine R Potgieter

    Full Text Available Belly-size ratings or belly scores are frequently used in carnivore research as a method of rating whether and how much an animal has eaten. This method provides only a rough ordinal measure of fullness and does not quantify the amount of food an animal has consumed. Here we present a method for estimating the amount of meat consumed by individual African wild dogs Lycaon pictus. We fed 0.5 kg pieces of meat to wild dogs being temporarily held in enclosures and measured the corresponding change in belly size using lateral side photographs taken perpendicular to the animal. The ratio of belly depth to body length was positively related to the mass of meat consumed and provided a useful estimate of the consumption. Similar relationships could be calculated to determine amounts consumed by other carnivores, thus providing a useful tool in the study of feeding behaviour.

  9. Estimation of organ-absorbed radiation doses during 64-detector CT coronary angiography using different acquisition techniques and heart rates: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Matsubara, Kosuke; Koshida, Kichiro; Kawashima, Hiroko (Dept. of Quantum Medical Technology, Faculty of Health Sciences, Kanazawa Univ., Kanazawa (Japan)), email: matsuk@mhs.mp.kanazawa-u.ac.jp; Noto, Kimiya; Takata, Tadanori; Yamamoto, Tomoyuki (Dept. of Radiological Technology, Kanazawa Univ. Hospital, Kanazawa (Japan)); Shimono, Tetsunori (Dept. of Radiology, Hoshigaoka Koseinenkin Hospital, Hirakata (Japan)); Matsui, Osamu (Dept. of Radiology, Faculty of Medicine, Kanazawa Univ., Kanazawa (Japan))

    2011-07-15

    Background: Though appropriate image acquisition parameters allow an effective dose below 1 mSv for CT coronary angiography (CTCA) performed with the latest dual-source CT scanners, a single-source 64-detector CT procedure results in a significant radiation dose due to its technical limitations. Therefore, estimating the radiation doses absorbed by an organ during 64-detector CTCA is important. Purpose: To estimate the radiation doses absorbed by organs located in the chest region during 64-detector CTCA using different acquisition techniques and heart rates. Material and Methods: Absorbed doses for breast, heart, lung, red bone marrow, thymus, and skin were evaluated using an anthropomorphic phantom and radiophotoluminescence glass dosimeters (RPLDs). Electrocardiogram (ECG)-gated helical and ECG-triggered non-helical acquisitions were performed by applying a simulated heart rate of 60 beats per minute (bpm) and ECG-gated helical acquisitions using ECG modulation (ECGM) of the tube current were performed by applying simulated heart rates of 40, 60, and 90 bpm after placing RPLDs on the anatomic location of each organ. The absorbed dose for each organ was calculated by multiplying the calibrated mean dose values of RPLDs with the mass energy coefficient ratio. Results: For all acquisitions, the highest absorbed dose was observed for the heart. When the helical and non-helical acquisitions were performed by applying a simulated heart rate of 60 bpm, the absorbed doses for heart were 215.5, 202.2, and 66.8 mGy for helical, helical with ECGM, and non-helical acquisitions, respectively. When the helical acquisitions using ECGM were performed by applying simulated heart rates of 40, 60, and 90 bpm, the absorbed doses for heart were 178.6, 139.1, and 159.3 mGy, respectively. Conclusion: ECG-triggered non-helical acquisition is recommended to reduce the radiation dose. Also, controlling the patients' heart rate appropriately during ECG-gated helical acquisition with

  10. Estimation and comparison of the radiation effective dose during coronary computed tomography angiography examinations on single-source 64-MDCT and dual-source 128-MDCT.

    Science.gov (United States)

    Khoramian, Daryoush; Sistani, Soroush

    2017-12-01

    To estimate and compare the radiation dose associated with coronary computed tomography angiography (CCTA) examinations on two multi-detector CT scanners (MDCT), 64-MDCT and 128-MDCT, in daily practice. Scan parameters of 90 patients undergoing retrospective electrocardiographic gating spiral CCTA exam were recorded during a period on a single-source 64-MDCT and a dual-source 128-MDCT, and average scan parameters were derived that were used for dosimetry. The computed tomography dose index (CTDI) with a pencil ionisation chamber and polymethyl methacrylate body phantom with diameter of 32 cm was measured on both scanners. The dose-length product (DLP) was calculated and the DLP to effective dose conversion factor (for chest scan at 120 kV of 0.014 mSv mGy -1 cm -1 ) was used to estimate effective dose (ED). Patients' heart rate, scan length, pitch factor, CTDIv, DLP and ED for 128-MDCT were 64 (5) (beats min -1 ), 161 (10) (mm), 0.26, 47 (12) (mGy), 769 (212) (mGy cm) and 10.3 (3.1) (mSv), respectively [mean (one standard deviation)]. Patients' heart rate, scan length, pitch factor, CTDIv, DLP and ED for 64-MDCT were 60 (7) (beats min -1 ), 172 (14) (mm), 0.2, 60 (6) (mGy), 1068 (98) (mGy cm) and 14.9 (1.4) (mSv), respectively. Our results indicated that the CTDIv, DLP and the effective dose with 128-MDCT is significantly lower than with 64-MDCT (p CT scanners was not significant (p > 0.05) and the kV was constant for both scanners (120 kV), the differences resulted from a shorter scan length on the 128-MDCT and use of a higher pitch factor (0.26 and 0.2 in the 128-MDCT and 64-MDCT, respectively). Comparison with other published studies confirms the findings and indicates methods for reducing patient dose.

  11. Pronation and supination after forearm fractures in children: Reliability of visual estimation and conventional goniometry measurement.

    Science.gov (United States)

    Colaris, Joost; van der Linden, Marleen; Selles, Ruud; Coene, Napoleon; Allema, Jan Hein; Verhaar, Jan

    2010-06-01

    Forearm fractures are common amongst children and often result in limited rotational function. In daily practice, pronation and supination of the arm are often visually estimated or measured using a conventional goniometer. The aim of this study was to compare the reliability of these two methods in paediatric patients who had previously sustained a forearm fracture. Intra- and interrater reliability of visual estimation and conventional goniometry were determined in 47 children who had previously sustained a forearm fracture. Intra- and interrater reliability of visual estimation and conventional goniometry was fair to excellent, with intraclass correlation coefficients (ICCs) ranging between 0.75 and 0.94. In addition, the overall goniometer data consistently showed lower smallest detectable differences (SDDs) compared to the visual estimation data, also indicating better reliability for the goniometer method. A conventional goniometer is an easy, fast and reliable method to determine the pronation and supination in a child who had sustained a forearm fracture. If an uncooperative child hinders the measurement, visual estimation is a good second choice. Measurements are more reliable when repeated by the same professional. Copyright 2010 Elsevier Ltd. All rights reserved.

  12. 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

  13. Accuracy and inter-observer reliability of visual estimation compared to clinical goniometry of the elbow.

    Science.gov (United States)

    Blonna, Davide; Zarkadas, Peter C; Fitzsimmons, James S; O'Driscoll, Shawn W

    2012-07-01

    To test the hypothesis that visual estimation by a trained observer is as accurate and reliable as clinical goniometry for measuring elbow range of motion. Instrument validity and inter-observer reliability of visual estimation was evaluated on a consecutive series of 50 elbow contractures. Four observers with different levels of elbow experience first estimated extension and flexion of the contracted elbows and then measured them with a blinded goniometer. Instrument validity for visually-based goniometry was extremely high. ICC scores were 0.97 for both extension and flexion estimations. Systematic error was negligible (1°) with upper limits of agreement being 9° (95% CI: 7°-11°) and 8° (95% CI: 6°-10°), respectively, for extension and flexion. For the expert surgeon, 92% of the visual estimates were within 5° of the value obtained by clinical goniometry. Between experienced observers (elbow surgeon and physician assistant), the ICC's were very high-0.96 for extension and 0.93 for flexion. The systematic errors were low, from -1° to 1° with upper limit of agreement being 11° (95% CI: 8°-14°). However, agreement was poor between an inexperienced study coordinator and the others (ICC's: 0.51-0.38, systematic errors: 8°-18°, upper limit of agreement: 32°-40°). The accuracy of the visual estimations made by the experienced elbow surgeon was as good as the measurements taken with a goniometer by the physician assistant or the clinical fellow and better than those taken by an inexperienced study coordinator. The trained human eye is highly capable of accurately estimating the range of motion of the elbow, compared to conventional clinical goniometry, depending on the experience of the observer. Diagnostic study, Level II.

  14. 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 ...

  15. The Prevalence of Age-Related Eye Diseases and Visual Impairment in Aging: Current Estimates

    Science.gov (United States)

    Klein, Ronald; Klein, Barbara E. K.

    2013-01-01

    Purpose. To examine prevalence of five age-related eye conditions (age-related cataract, AMD, open-angle glaucoma, diabetic retinopathy [DR], and visual impairment) in the United States. Methods. Review of published scientific articles and unpublished research findings. Results. Cataract, AMD, open-angle glaucoma, DR, and visual impairment prevalences are high in four different studies of these conditions, especially in people over 75 years of age. There are disparities among racial/ethnic groups with higher age-specific prevalence of DR, open-angle glaucoma, and visual impairment in Hispanics and blacks compared with whites, higher prevalence of age-related cataract in whites compared with blacks, and higher prevalence of late AMD in whites compared with Hispanics and blacks. The estimates are based on old data and do not reflect recent changes in the distribution of age and race/ethnicity in the United States population. There are no epidemiologic estimates of prevalence for many visually-impairing conditions. Conclusions. Ongoing prevalence surveys designed to provide reliable estimates of visual impairment, AMD, age-related cataract, open-angle glaucoma, and DR are needed. It is important to collect objective data on these and other conditions that affect vision and quality of life in order to plan for health care needs and identify areas for further research. PMID:24335069

  16. A Probabilistic Model of Visual Working Memory: Incorporating Higher Order Regularities into Working Memory Capacity Estimates

    Science.gov (United States)

    Brady, Timothy F.; Tenenbaum, Joshua B.

    2013-01-01

    When remembering a real-world scene, people encode both detailed information about specific objects and higher order information like the overall gist of the scene. However, formal models of change detection, like those used to estimate visual working memory capacity, assume observers encode only a simple memory representation that includes no…

  17. Comparing Visual and Digital Counting Methods to Estimate Horn Fly (Diptera: Muscidae) Populations on Cattle.

    Science.gov (United States)

    Smythe, B G; Urias, S; Wise, M E; Scholljegerdes, E J; Summers, A F; Bailey, D W

    2017-07-01

    Horn fly, Haematobia irritans (L.), population estimates often serve as a diagnostic tool prior to implementing managerial control options available to researchers and producers. Digital photographs taken of cattle infested with horn flies have been suggested to provide similarly accurate population estimates as compared with traditional visual assessments. The objective of this study was to compare visual and digital techniques used to estimate horn fly populations. Sixteen Angus × Hereford yearling heifers artificially infested with four levels of horn flies (Low = 0 flies; Medium = 250 flies; High = 500 flies; Extreme = 1,000 flies) were evaluated. Population estimates were taken visually by experienced (VE1) and inexperienced (VE2) technicians, as well as digitally, with photographs taken on both lateral sides of the south-facing animal. Horn flies were counted in both photographs and combined (CDC) for full body estimates. In addition, the highest photographed side population times two (DDC) was used for comparison. Estimations were made at 0700, 1200, and 1900 h the day following infestation. A time of observation × infestation level interaction (P < 0.01) was detected. On average, VE1 population estimates were greater (P < 0.01) than any other counting method observed. Morning estimates were greater (P < 0.05) than those taken at noon or in the early evening regardless of counting method. Further research regarding the standardization of these techniques to ensure more accurate population estimates is needed before these methods can be incorporated into integrated pest management programs. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Pilot-based parametric channel estimation algorithm for DCO-OFDM-based visual light communications

    Science.gov (United States)

    Qian, Xuewen; Deng, Honggui; He, Hailang

    2017-10-01

    Due to wide modulation bandwidth in optical communication, multipath channels may be non-sparse and deteriorate communication performance heavily. Traditional compressive sensing-based channel estimation algorithm cannot be employed in this kind of situation. In this paper, we propose a practical parametric channel estimation algorithm for orthogonal frequency division multiplexing (OFDM)-based visual light communication (VLC) systems based on modified zero correlation code (ZCC) pair that has the impulse-like correlation property. Simulation results show that the proposed algorithm achieves better performances than existing least squares (LS)-based algorithm in both bit error ratio (BER) and frequency response estimation.

  19. Abnormal course of the vertebral artery at the craniovertebral junction in patients with Down syndrome visualized by three-dimensional CT angiography

    International Nuclear Information System (INIS)

    Yamazaki, Masashi; Okawa, Akihiko; Hashimoto, Mitsuhiro; Aiba, Atsuomi; Someya, Yukio; Koda, Masao

    2008-01-01

    We determined the incidence of vertebral artery (VA) anomalies at the craniovertebral junction (CVJ) in patients with Down syndrome, and characterized the VA anomalies. The course of the VA in 46 consecutive patients who were due to undergo posterior arthrodesis surgery at the CVJ were evaluated by three-dimensional CT angiography (3DCTA). Included were five patients with Down syndrome who suffered from myelopathy due to atlantoaxial subluxation. All five patients with Down syndrome also had a simultaneous congenital skeletal anomaly, either os odontoideum or ossiculum terminale. Of the five patients with Down syndrome, three had VA anomalies at the CVJ, two had fenestration and one had a persistent first intersegmental artery. Of the other 41 patients without Down syndrome, five had VA anomalies at the CVJ. The incidence of VA anomalies at the CVJ was much higher in patients with Down syndrome than in those without Down syndrome. In planning surgery in patients with Down syndrome with symptomatic atlantoaxial subluxation and a congenital skeletal anomaly at the CVJ, we should consider the possible presence of VA anomalies. Preoperative 3DCTA allows us to precisely identify an anomalous VA and evaluate the possible risk of intraoperative VA injury in advance. (orig.)

  20. Abnormal course of the vertebral artery at the craniovertebral junction in patients with Down syndrome visualized by three-dimensional CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Masashi; Okawa, Akihiko; Hashimoto, Mitsuhiro; Aiba, Atsuomi; Someya, Yukio; Koda, Masao [Chiba University Graduate School of Medicine, Spine Section, Department of Orthopaedic Surgery, Chiba (Japan)

    2008-06-15

    We determined the incidence of vertebral artery (VA) anomalies at the craniovertebral junction (CVJ) in patients with Down syndrome, and characterized the VA anomalies. The course of the VA in 46 consecutive patients who were due to undergo posterior arthrodesis surgery at the CVJ were evaluated by three-dimensional CT angiography (3DCTA). Included were five patients with Down syndrome who suffered from myelopathy due to atlantoaxial subluxation. All five patients with Down syndrome also had a simultaneous congenital skeletal anomaly, either os odontoideum or ossiculum terminale. Of the five patients with Down syndrome, three had VA anomalies at the CVJ, two had fenestration and one had a persistent first intersegmental artery. Of the other 41 patients without Down syndrome, five had VA anomalies at the CVJ. The incidence of VA anomalies at the CVJ was much higher in patients with Down syndrome than in those without Down syndrome. In planning surgery in patients with Down syndrome with symptomatic atlantoaxial subluxation and a congenital skeletal anomaly at the CVJ, we should consider the possible presence of VA anomalies. Preoperative 3DCTA allows us to precisely identify an anomalous VA and evaluate the possible risk of intraoperative VA injury in advance. (orig.)

  1. 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

  2. Estimation of frequency and pretest probability of CAD in patients presenting with recent onset chest pain by multi-detector CT angiography

    Directory of Open Access Journals (Sweden)

    Omar Muayad Sultan

    2016-03-01

    Conclusion: CAD was seen in 77.5% in those with recent onset chest pain. Higher incidence of significant CAD was seen in hypertensive and diabetic patients. Family history is still not a reliable factor in our society. Male patient <60 years old has higher incidence of CAD than female in same age group. Pretest probability for CAD is a simple and important test as all patients in higher probability have CAD and most of them have significant disease so it is better to direct referral of them to conventional angiography to gain a benefit from direct intervention, radiation and cost benefit.

  3. Low-dose prospectively electrocardiogram-gated axial dual-source CT angiography in patients with pulsatile bilateral bidirectional Glenn Shunt: an alternative noninvasive method for postoperative morphological estimation.

    Directory of Open Access Journals (Sweden)

    Xiaopeng Ji

    Full Text Available To explore the clinical value of low-dose prospectively electrocardiogram-gated axial dual-source CT angiography (low-dose PGA scanning, CTA in patients with pulsatile bilateral bidirectional Glenn shunt (bBDG as an alternative noninvasive method for postoperative morphological estimation.Twenty patients with pulsatile bBDG (mean age 4.2±1.6 years underwent both low-dose PGA scanning and conventional cardiac angiography (CCA for the morphological changes. The morphological evaluation included the anatomy of superior vena cava (SVC and pulmonary artery (PA, the anastomotic location, thrombosis, aorto-pulmonary collateral circulation, pulmonary arteriovenous malformations, etc. Objective and subjective image quality was assessed. Bland-Altman analysis and linear regression analyses were used to evaluate the correlation on measurements between CTA and CCA. Effective radiation dose of both modalities was calculated.The CT attenuation value of bilateral SVC and PA was higher than 300 HU. The average subjective image quality score was 4.05±0.69. The morphology of bilateral SVC and PA was displayed completely and intuitively by CTA images. There were 24 SVC above PA and 15 SVC beside PA. Thrombosis was found in 1 patient. Collateral vessels were detected in 13 patients. No pulmonary arteriovenous malformation was found in our study. A strong correlation (R2>0.8, P0.The mean effective dose of CTA and CCA was 0.50±0.17 mSv and 4.85±1.34 mSv respectively.CT angiography with a low-dose PGA scanning is an accurate and reliable noninvasive examination in the assessment of morphological changes in patients with pulsatile bBDG.

  4. Numerosity estimation in visual stimuli in the absence of luminance-based cues.

    Directory of Open Access Journals (Sweden)

    Peter Kramer

    2011-02-01

    Full Text Available Numerosity estimation is a basic preverbal ability that humans share with many animal species and that is believed to be foundational of numeracy skills. It is notoriously difficult, however, to establish whether numerosity estimation is based on numerosity itself, or on one or more non-numerical cues like-in visual stimuli-spatial extent and density. Frequently, different non-numerical cues are held constant on different trials. This strategy, however, still allows numerosity estimation to be based on a combination of non-numerical cues rather than on any particular one by itself.Here we introduce a novel method, based on second-order (contrast-based visual motion, to create stimuli that exclude all first-order (luminance-based cues to numerosity. We show that numerosities can be estimated almost as well in second-order motion as in first-order motion.The results show that numerosity estimation need not be based on first-order spatial filtering, first-order density perception, or any other processing of luminance-based cues to numerosity. Our method can be used as an effective tool to control non-numerical variables in studies of numerosity estimation.

  5. High-resolution ex vivo magnetic resonance angiography: a feasibility study on biological and medical tissues

    Directory of Open Access Journals (Sweden)

    Boel Lene WT

    2010-03-01

    Full Text Available Abstract Background In biomedical sciences, ex vivo angiography is a practical mean to elucidate vascular structures three-dimensionally with simultaneous estimation of intravascular volume. The objectives of this study were to develop a magnetic resonance (MR method for ex vivo angiography and to compare the findings with computed tomography (CT. To demonstrate the usefulness of this method, examples are provided from four different tissues and species: the human placenta, a rice field eel, a porcine heart and a turtle. Results The optimal solution for ex vivo MR angiography (MRA was a compound containing gelatine (0.05 g/mL, the CT contrast agent barium sulphate (0.43 mol/L and the MR contrast agent gadoteric acid (2.5 mmol/L. It was possible to perform angiography on all specimens. We found that ex vivo MRA could only be performed on fresh tissue because formalin fixation makes the blood vessels permeable to the MR contrast agent. Conclusions Ex vivo MRA provides high-resolution images of fresh tissue and delineates fine structures that we were unable to visualise by CT. We found that MRA provided detailed information similar to or better than conventional CTA in its ability to visualize vessel configuration while avoiding interfering signals from adjacent bones. Interestingly, we found that vascular tissue becomes leaky when formalin-fixed, leading to increased permeability and extravascular leakage of MR contrast agent.

  6. Estimation of Visual Maps with a Robot Network Equipped with Vision Sensors

    Directory of Open Access Journals (Sweden)

    Arturo Gil

    2010-05-01

    Full Text Available In this paper we present an approach to the Simultaneous Localization and Mapping (SLAM problem using a team of autonomous vehicles equipped with vision sensors. The SLAM problem considers the case in which a mobile robot is equipped with a particular sensor, moves along the environment, obtains measurements with its sensors and uses them to construct a model of the space where it evolves. In this paper we focus on the case where several robots, each equipped with its own sensor, are distributed in a network and view the space from different vantage points. In particular, each robot is equipped with a stereo camera that allow the robots to extract visual landmarks and obtain relative measurements to them. We propose an algorithm that uses the measurements obtained by the robots to build a single accurate map of the environment. The map is represented by the three-dimensional position of the visual landmarks. In addition, we consider that each landmark is accompanied by a visual descriptor that encodes its visual appearance. The solution is based on a Rao-Blackwellized particle filter that estimates the paths of the robots and the position of the visual landmarks. The validity of our proposal is demonstrated by means of experiments with a team of real robots in a office-like indoor environment.

  7. Automatic Conflict Monitoring by Event-Related Potentials Could be used to Estimate Visual Acuity Levels.

    Science.gov (United States)

    Huang, Wenwen; Liu, Sinan; Luo, Bin; Meng, Huanhuan; Ji, Mengmeng; Li, Maojuan; Chen, Xiping; Tao, Luyang

    2018-03-15

    Numerous studies have explored the physical attribute features or face perceptions in conflict processing, while complicate gradient conflicts were rarely discussed. The aim of the study was to discuss the relationship between the event-related potential (ERP) component features and different visual acuity levels by using the modified S1-S2 task under non-attention status. Three visual acuity levels were applied, each with four orientations of "E" optotype stimuli randomly presented in the center of the visual field while participants were required to concentrate on listening to stories. The results showed that the amplitudes of P1 and P3 as well as difference P3 were larger in supra-threshold condition. In threshold condition, larger amplitudes for both N2 and difference N2 exhibited in frontal and central areas. In sub-threshold condition, there was no endogenous component elicited by mismatch stimuli except smaller anterior N1. Meanwhile, the specific distributions of N1 and N2 were presented and compared with previous face processing. The findings showed that visual conflict processing took place not only at an early stage but also at the late period, which might be as the consequences of interaction between conflict strength and involuntary attention. We concluded that automatic conflict detecting of visual icons by the serial ERP components could distinguish different visual acuity levels. The involvement of endogenous components could reveal the specific mechanism of more precise and fine conflict identification of complex physical attributes under non-attention status, furthermore could be used as valid markers to estimate the magnitude of visual acuity objectively. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

  8. Estimation of metallurgical parameters of flotation process from froth visual features

    Directory of Open Access Journals (Sweden)

    Mohammad Massinaei

    2015-06-01

    Full Text Available The estimation of metallurgical parameters of flotation process from froth visual features is the ultimate goal of a machine vision based control system. In this study, a batch flotation system was operated under different process conditions and metallurgical parameters and froth image data were determined simultaneously. Algorithms have been developed for measuring textural and physical froth features from the captured images. The correlation between the froth features and metallurgical parameters was successfully modeled, using artificial neural networks. It has been shown that the performance parameters of flotation process can be accurately estimated from the extracted image features, which is of great importance for developing automatic control systems.

  9. 6-DOF Pose Estimation of a Robotic Navigation Aid by Tracking Visual and Geometric Features.

    Science.gov (United States)

    Ye, Cang; Hong, Soonhac; Tamjidi, Amirhossein

    2015-10-01

    This paper presents a 6-DOF Pose Estimation (PE) method for a Robotic Navigation Aid (RNA) for the visually impaired. The RNA uses a single 3D camera for PE and object detection. The proposed method processes the camera's intensity and range data to estimates the camera's egomotion that is then used by an Extended Kalman Filter (EKF) as the motion model to track a set of visual features for PE. A RANSAC process is employed in the EKF to identify inliers from the visual feature correspondences between two image frames. Only the inliers are used to update the EKF's state. The EKF integrates the egomotion into the camera's pose in the world coordinate system. To retain the EKF's consistency, the distance between the camera and the floor plane (extracted from the range data) is used by the EKF as the observation of the camera's z coordinate. Experimental results demonstrate that the proposed method results in accurate pose estimates for positioning the RNA in indoor environments. Based on the PE method, a wayfinding system is developed for localization of the RNA in a home environment. The system uses the estimated pose and the floorplan to locate the RNA user in the home environment and announces the points of interest and navigational commands to the user through a speech interface. This work was motivated by the limitations of the existing navigation technology for the visually impaired. Most of the existing methods use a point/line measurement sensor for indoor object detection. Therefore, they lack capability in detecting 3D objects and positioning a blind traveler. Stereovision has been used in recent research. However, it cannot provide reliable depth data for object detection. Also, it tends to produce a lower localization accuracy because its depth measurement error quadratically increases with the true distance. This paper suggests a new approach for navigating a blind traveler. The method uses a single 3D time-of-flight camera for both 6-DOF PE and 3D object

  10. Isolated retinal cotton wool spot after coronary angiography

    Directory of Open Access Journals (Sweden)

    Nikolaos Kopsachilis

    2013-01-01

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

  11. Isolated retinal cotton wool spot after coronary angiography.

    Science.gov (United States)

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

    2013-01-01

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

  12. Visual estimation versus gravimetric measurement of postpartum blood loss: a prospective cohort study.

    Science.gov (United States)

    Al Kadri, Hanan M F; Al Anazi, Bedayah K; Tamim, Hani M

    2011-06-01

    One of the major problems in international literature is how to measure postpartum blood loss with accuracy. We aimed in this research to assess the accuracy of visual estimation of postpartum blood loss (by each of two main health-care providers) compared with the gravimetric calculation method. We carried out a prospective cohort study at King Abdulaziz Medical City, Riyadh, Saudi Arabia between 1 November 2009 and 31 December 2009. All women who were admitted to labor and delivery suite and delivered vaginally were included in the study. Postpartum blood loss was visually estimated by the attending physician and obstetrics nurse and then objectively calculated by a gravimetric machine. Comparison between the three methods of blood loss calculation was carried out. A total of 150 patients were included in this study. There was a significant difference between the gravimetric calculated blood loss and both health-care providers' estimation with a tendency to underestimate the loss by about 30%. The background and seniority of the assessing health-care provider did not affect the accuracy of the estimation. The corrected incidence of postpartum hemorrhage in Saudi Arabia was found to be 1.47%. Health-care providers tend to underestimate the volume of postpartum blood loss by about 30%. Training and continuous auditing of the diagnosis of postpartum hemorrhage is needed to avoid missing cases and thus preventing associated morbidity and mortality.

  13. A noise-optimized virtual monochromatic reconstruction algorithm improves stent visualization and diagnostic accuracy for detection of in-stent re-stenosis in lower extremity run-off CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, Stefanie [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); De Cecco, Carlo N.; Yamada, Ricardo T.; Varga-Szemes, Akos; Stubenrauch, Andrew C.; Fuller, Stephen R. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Schoepf, U.J. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Caruso, Damiano [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncology and Pathology, Rome (Italy); Vogl, Thomas J.; Wichmann, Julian L. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Nikolaou, Konstantin [Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Todoran, Thomas M. [Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States)

    2016-12-15

    To evaluate the impact of noise-optimized virtual monochromatic imaging (VMI+) on stent visualization and accuracy for in-stent re-stenosis at lower extremity dual-energy CT angiography (DE-CTA). We evaluated third-generation dual-source DE-CTA studies in 31 patients with prior stent placement. Images were reconstructed with linear blending (F{sub 0}.5) and VMI+ at 40-150 keV. In-stent luminal diameter was measured and contrast-to-noise ratio (CNR) calculated. Diagnostic confidence was determined using a five-point scale. In 21 patients with invasive catheter angiography, accuracy for significant re-stenosis (≥50 %) was assessed at F{sub 0}.5 and 80 keV-VMI+ chosen as the optimal energy level based on image-quality analysis. At CTA, 45 stents were present. DSA was available for 28 stents whereas 12 stents showed significant re-stenosis. CNR was significantly higher with ≤80 keV-VMI+ (17.9 ± 6.4-33.7 ± 12.3) compared to F{sub 0}.5 (16.9 ± 4.8; all p < 0.0463); luminal stent diameters were increased at ≥70 keV (5.41 ± 1.8-5.92 ± 1.7 vs. 5.27 ± 1.8, all p < 0.001) and diagnostic confidence was highest at 70-80 keV-VMI+ (4.90 ± 0.48-4.88 ± 0.63 vs. 4.60 ± 0.66, p = 0.001, 0.0042). Sensitivity, negative predictive value and accuracy for re-stenosis were higher with 80 keV-VMI+ (100, 100, 96.4 %) than F{sub 0}.5 (90.9, 94.1, 89.3 %). 80 keV-VMI+ improves image quality, diagnostic confidence and accuracy for stent evaluation at lower extremity DE-CTA. (orig.)

  14. [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.

  15. Development of Categories of Colour Similarity Estimation Algorithm for Persons with Low Visual Capability Using Artificial Neural Network

    Science.gov (United States)

    Fujisawa, Shoichiro; Kurozumi, Ryota; Mitani, Seiji; Sueda, Osamu

    In Japan, it is reported about 90% of the persons with visual impairment are the persons with low visual capability. However, the database of the low visual capability and the standard about the easily comprehensible visual information presentation are not existed yet. Therefore, the categories of colour similarity of the persons with low visual capability are measured. However, measuring various colour combinations is placing a burden on the object person. Therefore, in this research, development of the categories of colour similarity estimation algorithm is proposed. Applying the generalization capability of the artificial neural network, the distribution of the categories of colour similarity will be obtained from the limited colour combination measures.

  16. Isolated retinal cotton wool spot after coronary angiography

    OpenAIRE

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

    2013-01-01

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

  17. Differences in characteristics of raters who use the visual estimation method in hospitals based on their training experiences.

    Science.gov (United States)

    Kawasaki, Yui; Tamaura, Yuki; Akamatsu, Rie; Sakai, Masashi; Fujiwara, Keiko

    2018-02-07

    Despite a clinical need, only a few studies have provided information concerning visual estimation training for raters to improve the validity of their evaluations. This study aims to describe the differences in the characteristics of raters who evaluated patients' dietary intake in hospitals using the visual estimation method based on their training experiences. We collected data from three hospitals in Tokyo from August to September 2016. The participants were 199 nursing staff members, and they completed a self-administered questionnaire on demographic data; working career; training in the visual estimation method; knowledge, attitude, and practice associated with nutritional care; and self-evaluation of method validity of and skills of visual estimation. We classified participants into two groups, experienced and inexperienced, based on whether they had received training. Square test, Mann-Whitney U test, and univariable and multivariable logistic regression analysis were used to describe the differences between these two groups in terms of their characteristics; knowledge, attitude, and practice associated with nutritional care; and self-evaluation of method validity and tips used in the visual estimation method. Of the 158 staff members (79.4%) (118 nurses and 40 nursing assistants) who agreed to participate in the analysis, thirty-three participants (20.9%) were trained in the visual estimation method. Participants who had received training had better knowledge (2.70 ± 0.81, score range was 1-5) than those who had not received any training (2.34 ± 0.74, p = 0.03). Score of self-evaluation of method validity of the visual estimation method was higher in the experienced group (3.78 ± 0.61, score range was 1-5) than the inexperienced group (3.40 ± 0.66, p trained had adequate knowledge (OR: 2.78, 95% CI: 1.05-7.35) and frequently used tips in visual estimation (OR: 1.85, 95% CI: 1.26-2.73). Trained participants had more required knowledge and

  18. Defining the real-world reproducibility of visual grading of left ventricular function and visual estimation of left ventricular ejection fraction: impact of image quality, experience and accreditation.

    Science.gov (United States)

    Cole, Graham D; Dhutia, Niti M; Shun-Shin, Matthew J; Willson, Keith; Harrison, James; Raphael, Claire E; Zolgharni, Massoud; Mayet, Jamil; Francis, Darrel P

    2015-10-01

    Left ventricular function can be evaluated by qualitative grading and by eyeball estimation of ejection fraction (EF). We sought to define the reproducibility of these techniques, and how they are affected by image quality, experience and accreditation. Twenty apical four-chamber echocardiographic cine loops (Online Resource 1-20) of varying image quality and left ventricular function were anonymized and presented to 35 operators. Operators were asked to provide (1) a one-phrase grading of global systolic function (2) an "eyeball" EF estimate and (3) an image quality rating on a 0-100 visual analogue scale. Each observer viewed every loop twice unknowingly, a total of 1400 viewings. When grading LV function into five categories, an operator's chance of agreement with another operator was 50% and with themself on blinded re-presentation was 68%. Blinded eyeball LVEF re-estimates by the same operator had standard deviation (SD) of difference of 7.6 EF units, with the SD across operators averaging 8.3 EF units. Image quality, defined as the average of all operators' assessments, correlated with EF estimate variability (r = -0.616, p visual grading agreement (r = 0.58, p visual grading of LV function and LVEF estimation is dependent on image quality, but individuals cannot themselves identify when poor image quality is disrupting their LV function estimate. Clinicians should not assume that patients changing in grade or in visually estimated EF have had a genuine clinical change.

  19. Spatial bias in estimating the position of visual and proprioceptive targets.

    Science.gov (United States)

    Liu, Yang; Sexton, Brandon Montgomery; Block, Hannah J

    2018-02-21

    When people match an unseen hand to a visual or proprioceptive target, they make both variable and systematic (bias) errors. Variance is a well-established factor in behavior, but the origin and implications of bias, and its connection to variance, are poorly understood. Eighty healthy adults matched their unseen right index finger to proprioceptive (left index finger) and visual targets with no performance feedback. We asked whether matching bias was related to target modality and to the magnitude or spatial properties of matching variance. Bias errors were affected by target modality, with subjects estimating visual and proprioceptive targets 20 mm apart. We found three pieces of evidence to suggest a connection between bias and variable errors: (1) for most subjects, the target modality that yielded greater spatial bias was also estimated with greater variance; (2) magnitudes of matching bias and variance were somewhat correlated for each target modality (R = 0.24 and 0.29); and (3), bias direction was closely related to the angle of the major axis of the confidence ellipse (R = 0.60 and 0.63). However, while variance was significantly correlated with visuo-proprioceptive weighting as predicted by multisensory integration theory (R = -0.29 and 0.27 for visual and proprioceptive variance, respectively), bias was not. In a second session, subjects improved their matching variance, but not bias, for both target modalities, indicating a difference in stability. Taken together, these results suggest bias and variance are related only in some respects, which should be considered in the study of multisensory behavior.

  20. 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.

  1. 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

  2. Individual differences in rate of encoding predict estimates of visual short-term memory capacity (K).

    Science.gov (United States)

    Jannati, Ali; McDonald, John J; Di Lollo, Vincent

    2015-06-01

    The capacity of visual short-term memory (VSTM) is commonly estimated by K scores obtained with a change-detection task. Contrary to common belief, K may be influenced not only by capacity but also by the rate at which stimuli are encoded into VSTM. Experiment 1 showed that, contrary to earlier conclusions, estimates of VSTM capacity obtained with a change-detection task are constrained by temporal limitations. In Experiment 2, we used change-detection and backward-masking tasks to obtain separate within-subject estimates of K and of rate of encoding, respectively. A median split based on rate of encoding revealed significantly higher K estimates for fast encoders. Moreover, a significant correlation was found between K and the estimated rate of encoding. The present findings raise the prospect that the reported relationships between K and such cognitive concepts as fluid intelligence may be mediated not only by VSTM capacity but also by rate of encoding. (c) 2015 APA, all rights reserved).

  3. Sonification of reference markers for auditory graphs: effects on non-visual point estimation tasks

    Directory of Open Access Journals (Sweden)

    Oussama Metatla

    2016-04-01

    Full Text Available Research has suggested that adding contextual information such as reference markers to data sonification can improve interaction with auditory graphs. This paper presents results of an experiment that contributes to quantifying and analysing the extent of such benefits for an integral part of interacting with graphed data: point estimation tasks. We examine three pitch-based sonification mappings; pitch-only, one-reference, and multiple-references that we designed to provide information about distance from an origin. We assess the effects of these sonifications on users’ performances when completing point estimation tasks in a between-subject experimental design against visual and speech control conditions. Results showed that the addition of reference tones increases users accuracy with a trade-off for task completion times, and that the multiple-references mapping is particularly effective when dealing with points that are positioned at the midrange of a given axis.

  4. Estimates of Incidence and Prevalence of Visual Impairment, Low Vision, and Blindness in the United States.

    Science.gov (United States)

    Chan, Tiffany; Friedman, David S; Bradley, Chris; Massof, Robert

    2018-01-01

    Updated estimates of the prevalence and incidence rates of low vision and blindness are needed to inform policy makers and develop plans to meet the future demands for low vision rehabilitation services. To provide updated estimates of the incidence and prevalence of low vision and blindness in the United States. Visual acuity measurements as a function of age from the 2007-2008 National Health and Nutrition Examination Survey, with representation of racial and ethnic groups, were used to estimate the prevalence and incidence of visual impairments. Data from 6016 survey participants, ranging in age from younger than 18 years to older than 45 years, were obtained to estimate prevalence rates for different age groups. Incidence and prevalence rates of low vision (best-corrected visual acuity [BCVA] in the better-seeing eye of United States were estimated, using the 2010 US census data by age, from the rate models applied to the census projections for 2017, 2030, and 2050. Data were collected from November 1, 2007, to October 31, 2008. Data analysis took place from March 31, 2016, to March 19, 2017. Prevalence and incidence rates of low vision and blindness in the United States. Of the 6016 people in the study, 1714 (28.4%) were younger than 18 years of age, 2358 (39.1%) were 18 to 44 years of age, and 1944 (32.3%) were 45 years of age or older. There were 2888 male (48%) and 3128 female (52%) participants. The prevalence of low vision and blindness for older adults (≥45 years) in the United States in 2017 is estimated to be 3 894 406 persons (95% CI, 3 034 442-4 862 549 persons) with a BCVA less than 20/40, 1 483 703 persons (95% CI, 968 656-2 370 513 persons) with a BCVA less than 20/60, and 1 082 790 persons (95% CI, 637 771-1 741 864 persons) with a BCVA of 20/200 or less. The estimated 2017 annual incidence (projected from 2010 census data) of low vision and blindness among older adults (≥45 years) in the United States is 481

  5. Magnetic resonance angiography of fetal vasculature at 3.0 T

    OpenAIRE

    Neelavalli, Jaladhar; Krishnamurthy, Uday; Jella, Pavan K.; Mody, Swati S.; Yadav, Brijesh K.; Hendershot, Kelly; Hernandez-Andrade, Edgar; Yeo, Lami; Cabrera, Maria D.; Haacke, Ewart M.; Hassan, Sonia S.; Romero, Roberto

    2016-01-01

    Magnetic resonance angiography has not been used much previously for visualizing fetal vessels in utero for reasons that include a contraindication for the use of exogenous contrast agents, maternal respiratory motion and fetal motion. In this work, we report the feasibility of using an appropriately modified clinical time-of-flight magnetic resonance imaging sequence for non-contrast angiography of human fetal and placental vessels at 3.0 T. Using this 2D angiography technique, it is possibl...

  6. 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

  7. Genetic parameters estimates and visual selection for leaves production in Ilex paraguariensis

    Directory of Open Access Journals (Sweden)

    José Alfredo Sturion

    2017-08-01

    Full Text Available ABSTRACT The selection of yerba mate superior genotypes, based on each plant leaf weight, is based on genetic parameters obtained from experimental plantations and it is practically impossible from the fourth year of age. Therefore, we estimate genetic parameters and check the feasibility of selection through notes and weight estimates of each tree at 18.5 years of age. The genetic material consists of a combined trial of provenances and progenies of half-sibs with 140 progenies from 7 provenances, installed in Ivaí, Paraná, Brazil, in a randomized block design with 10 repetitions. The genetic control of leaf production is of low magnitude (ĥ2a= 0.175042 ± 0.0393 revealing high influence of the environment. The additive genetic correlations between the real weight of leaves × notes and real weight of leaves × visually estimated weight were of high magnitude (higher than 88%. Thus, the selection based on the leaves weight can be carried out without major losses in genetic gains by both methodologies when the purpose is the sexual selection, in which case the sort order has no importance. In the case of vegetative propagation, aiming clonal plantations, in which only the plants with the highest genotypic values should be selected, the selection by means of notes and leaves weight estimates proved to be inefficient.

  8. Preterm-associated visual impairment and estimates of retinopathy of prematurity at regional and global levels for 2010

    Science.gov (United States)

    Blencowe, Hannah; Lawn, Joy E.; Vazquez, Thomas; Fielder, Alistair; Gilbert, Clare

    2013-01-01

    Background: Retinopathy of prematurity (ROP) is a leading cause of potentially avoidable childhood blindness worldwide. We estimated ROP burden at the global and regional levels to inform screening and treatment programs, research, and data priorities. Methods: Systematic reviews and meta-analyses were undertaken to estimate the risk of ROP and subsequent visual impairment for surviving preterm babies by level of neonatal care, access to ROP screening, and treatment. A compartmental model was used to estimate ROP cases and numbers of visually impaired survivors. Results: In 2010, an estimated 184,700 (uncertainty range: 169,600–214,500) preterm babies developed any stage of ROP, 20,000 (15,500–27,200) of whom became blind or severely visually impaired from ROP, and a further 12,300 (8,300–18,400) developed mild/moderate visual impairment. Sixty-five percent of those visually impaired from ROP were born in middle-income regions; 6.2% (4.3–8.9%) of all ROP visually impaired infants were born at >32-wk gestation. Visual impairment from other conditions associated with preterm birth will affect larger numbers of survivors. Conclusion: Improved care, including oxygen delivery and monitoring, for preterm babies in all facility settings would reduce the number of babies affected with ROP. Improved data tracking and coverage of locally adapted screening/treatment programs are urgently required. PMID:24366462

  9. Basin Visual Estimation Technique (BVET) and Representative Reach Approaches to Wadeable Stream Surveys: Methodological Limitations and Future Directions

    Science.gov (United States)

    Lance R. Williams; Melvin L. Warren; Susan B. Adams; Joseph L. Arvai; Christopher M. Taylor

    2004-01-01

    Basin Visual Estimation Techniques (BVET) are used to estimate abundance for fish populations in small streams. With BVET, independent samples are drawn from natural habitat units in the stream rather than sampling "representative reaches." This sampling protocol provides an alternative to traditional reach-level surveys, which are criticized for their lack...

  10. Variability in abundance of temperate reef fishes estimated by visual census.

    Directory of Open Access Journals (Sweden)

    Alejo J Irigoyen

    Full Text Available Identifying sources of sampling variation and quantifying their magnitude is critical to the interpretation of ecological field data. Yet, most monitoring programs of reef fish populations based on underwater visual censuses (UVC consider only a few of the factors that may influence fish counts, such as the diver or census methodology. Recent studies, however, have drawn attention to a broader range of processes that introduce variability at different temporal scales. This study analyzes the magnitude of different sources of variation in UVCs of temperate reef fishes off Patagonia (Argentina. The variability associated with time-of-day, tidal state, and time elapsed between censuses (minutes, days, weeks and months was quantified for censuses conducted on the five most conspicuous and common species: Pinguipes brasilianus, Pseudopercis semifasciata, Sebastes oculatus, Acanthistius patachonicus and Nemadactylus bergi. Variance components corresponding to spatial heterogeneity and to the different temporal scales were estimated using nested random models. The levels of variability estimated for the different species were related to their life history attributes and behavior. Neither time-of-day nor tidal state had a significant effect on counts, except for the influence of tide on P. brasilianus. Spatial heterogeneity was the dominant source of variance in all but one species. Among the temporal scales, the intra-annual variation was the highest component for most species due to marked seasonal fluctuations in abundance, followed by the weekly and the instantaneous variation; the daily component was not significant. The variability between censuses conducted at different tidal levels and time-of-day was similar in magnitude to the instantaneous variation, reinforcing the conclusion that stochastic variation at very short time scales is non-negligible and should be taken into account in the design of monitoring programs and experiments. The present

  11. 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

  12. 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

  13. Lateral Trunk Surface as a new parameter to estimate live body weight by Visual Image Analysis

    Directory of Open Access Journals (Sweden)

    S. Terramoccia

    2010-02-01

    Full Text Available Live weight of 74 milking Mediterranean buffaloes (Bubalus bubalis L. have been estimated by Visual Image Analysis. The total surface of lateral profile, tested in previous researches with viable result, was substituted by the measurement of the Lateral Trunk Surface (LTrS. The measurements were recorded by a camera equipped by a laser distance recorder and data were elaborated by a specific software. This parameter, eliminating the surface of neck, head and legs, that are less easily measurable, simplified and accelerated the procedure. Correlation between LTrS and live weight was r = 0.90 (P < 0.01. A significant equation (P < 0.01 was obtained from the recorded data of a random sample of 38 buffaloes. When the validation of the equation was tested on the other 36 subjects, the estimated live weight had a mean of 691.74 kg ± 68.55. This was corresponding to a 1.08% overestimation of the real weight.

  14. 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

  15. 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

  16. 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.)

  17. 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

  18. Magnetic resonance angiography of fetal vasculature at 3.0 T

    Energy Technology Data Exchange (ETDEWEB)

    Neelavalli, Jaladhar; Krishnamurthy, Uday; Yadav, Brijesh K.; Haacke, Ewart M. [Wayne State University School of Medicine, Department of Radiology, Detroit, MI (United States); Wayne State University, Department of Biomedical Engineering, Detroit, MI (United States); Jella, Pavan K.; Hendershot, Kelly; Cabrera, Maria D. [Wayne State University School of Medicine, Department of Radiology, Detroit, MI (United States); Mody, Swati S. [Wayne State University School of Medicine, Department of Radiology, Detroit, MI (United States); Children' s Hospital of Michigan, Department of Radiology, Detroit, MI (United States); Hernandez-Andrade, Edgar; Yeo, Lami; Hassan, Sonia S. [Wayne State University, Department of Obstetrics and Gynecology, Detroit, MI (United States); Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, MI (United States); Romero, Roberto [Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, and Detroit, MI (United States); University of Michigan, Department of Obstetrics and Gynecology, Ann Arbor, MI (United States); Michigan State University, Department of Epidemiology and Biostatistics, East Lansing, MI (United States); Wayne State University, Center for Molecular Medicine and Genetics, Detroit, MI (United States)

    2016-12-15

    Magnetic resonance angiography has not been used much previously for visualizing fetal vessels in utero for reasons that include a contraindication for the use of exogenous contrast agents, maternal respiratory motion and fetal motion. In this work, we report the feasibility of using an appropriately modified clinical time-of-flight magnetic resonance imaging sequence for non-contrast angiography of human fetal and placental vessels at 3.0 T. Using this 2D angiography technique, it is possible to visualize fetal vascular networks in late pregnancy. (orig.)

  19. Magnetic resonance angiography of fetal vasculature at 3.0 T

    Science.gov (United States)

    Krishnamurthy, Uday; Jella, Pavan K.; Mody, Swati S.; Yadav, Brijesh K.; Hendershot, Kelly; Hernandez-Andrade, Edgar; Yeo, Lami; Cabrera, Maria D.; Haacke, Ewart M.; Hassan, Sonia S.; Romero, Roberto

    2016-01-01

    Magnetic resonance angiography has not been used much previously for visualizing fetal vessels in utero for reasons that include a contraindication for the use of exogenous contrast agents, maternal respiratory motion and fetal motion. In this work, we report the feasibility of using an appropriately modified clinical time-of-flight magnetic resonance imaging sequence for non-contrast angiography of human fetal and placental vessels at 3.0 T. Using this 2D angiography technique, it is possible to visualize fetal vascular networks in late pregnancy. PMID:27189488

  20. Magnetic resonance angiography of fetal vasculature at 3.0 T

    International Nuclear Information System (INIS)

    Neelavalli, Jaladhar; Krishnamurthy, Uday; Yadav, Brijesh K.; Haacke, Ewart M.; Jella, Pavan K.; Hendershot, Kelly; Cabrera, Maria D.; Mody, Swati S.; Hernandez-Andrade, Edgar; Yeo, Lami; Hassan, Sonia S.; Romero, Roberto

    2016-01-01

    Magnetic resonance angiography has not been used much previously for visualizing fetal vessels in utero for reasons that include a contraindication for the use of exogenous contrast agents, maternal respiratory motion and fetal motion. In this work, we report the feasibility of using an appropriately modified clinical time-of-flight magnetic resonance imaging sequence for non-contrast angiography of human fetal and placental vessels at 3.0 T. Using this 2D angiography technique, it is possible to visualize fetal vascular networks in late pregnancy. (orig.)

  1. Usefulness of a novel calibrated hood to determine indications for colon polypectomy: visual estimation of polyp size is not accurate.

    Science.gov (United States)

    Watanabe, Tatsuyuki; Kume, Keiichiro; Yoshikawa, Ichiro; Harada, Masaru

    2015-07-01

    Accurate measurement of polyp size during colonoscopy is important because the size is a surrogate marker of cancer, but a standardized measurement technique to measure polyp size has yet to be determined. We have developed a new device "a novel calibrated hood." We assessed polyp size by visual estimation and measurement using the calibrated hood. Patients who underwent polypectomy from November 2012 to September 2013 and who had received screening colonoscopy within 6 months prior to the polypectomy were included in this study. Polypectomy was performed attaching the calibrated hood. The endoscopist measured the polyp size using the calibrated hood. Polyp size was compared between visual estimation and measurement using the calibrated hood. Seventy-five patients with 157 polyps were included. Seventy-seven polyps fulfilled the selection criteria. Mean polyp size by visual estimation was 6.57 ± 2.15, and by using calibrated hood was 5.94 ± 1.73 (p = 0.005). There was a significant difference between measurements using the calibrated hood vs. visual estimation by inexperienced trainees; however, there was no difference in case of well-experienced endoscopists. By visual estimation, 11 of 19 polyps were decided for ≥5 mm despite being less than 5 mm, and 5 of 58 polyps were decided for estimation of polyp size is not accurate. It is important to measure the size by an objective way, and the calibrated hood is useful in measuring polyp size, from the standpoint of accurately determining indication for polypectomy.

  2. Rationale and design of the worldwide prospective multicenter registry on radiation dose estimates of cardiac CT angiography in daily practice in 2017 (PROTECTION VI)

    DEFF Research Database (Denmark)

    Stocker, Thomas J; Deseive, Simon; Chen, Marcus

    2018-01-01

    -randomized and randomized studies have been performed to reduce the associated radiation exposure. Currently, it is unclear if the advances in technology and knowledge about radiation reduction translated into reduced levels of cardiac CTA radiation dose in daily clinical practice as well as a wide utilization of dose......-saving strategies. METHODS: The PROTECTION VI study is a multicenter, prospective, worldwide registry designed to evaluate radiation dose exposure, utilization of dose-saving strategies and diagnostic image quality during cardiac CTA in current daily practice. Assessment of image quality will be addressed...... median radiation dose levels, image quality, frequency of use and efficacy of algorithms for dose reduction, and patient and study-related predictors associated with radiation dose. CONCLUSIONS: The PROTECTION VI study is designed to provide a reliable estimate of current radiation dose for cardiac CTA...

  3. Accuracy of using visual identification of white sharks to estimate residency patterns.

    Directory of Open Access Journals (Sweden)

    David G Delaney

    Full Text Available Determining the residency of an aquatic species is important but challenging and it remains unclear what is the best sampling methodology. Photo-identification has been used extensively to estimate patterns of animals' residency and is arguably the most common approach, but it may not be the most effective approach in marine environments. To examine this, in 2005, we deployed acoustic transmitters on 22 white sharks (Carcharodon carcharias in Mossel Bay, South Africa to quantify the probability of detecting these tagged sharks by photo-identification and different deployment strategies of acoustic telemetry equipment. Using the data collected by the different sampling approaches (detections from an acoustic listening station deployed under a chumming vessel versus those from visual sightings and photo-identification, we quantified the methodologies' probability of detection and determined if the sampling approaches, also including an acoustic telemetry array, produce comparable results for patterns of residency. Photo-identification had the lowest probability of detection and underestimated residency. The underestimation is driven by various factors primarily that acoustic telemetry monitors a large area and this reduces the occurrence of false negatives. Therefore, we propose that researchers need to use acoustic telemetry and also continue to develop new sampling approaches as photo-identification techniques are inadequate to determine residency. Using the methods presented in this paper will allow researchers to further refine sampling approaches that enable them to collect more accurate data that will result in better research and more informed management efforts and policy decisions.

  4. Intrarater and interrater reliability of first metatarsophalangeal joint dorsiflexion: goniometry versus visual estimation.

    Science.gov (United States)

    Jones, Angela M; Curran, Sarah A

    2012-01-01

    Visual estimation (VE) and goniometric measurement (GM) are commonly used to assess first metatarsophalangeal joint dorsiflexion. The purposes of this study were to determine the intrarater and interrater reliability of VE and GM and to establish whether reliability was influenced by the experience of the examiner. Ten experienced and ten inexperienced examiners evaluated three real-size photographs of a first metatarsophalangeal joint positioned in various degrees of dorsiflexion on two separate occasions. Experienced examiners demonstrated excellent intrarater and interrater reliability for GM (intraclass correlation coefficient [ICC], >0.953; standard error of measurement [SEM], 1.8°-2.5°) compared with inexperienced examiners, who showed fair-to-good intrarater and interrater reliability (ICC, 0.322-0.597; SEM, 2.0°-3.0°). For VE, inexperienced examiners demonstrated fair-to-good interrater and excellent intra-rater reliability (ICC, 0.666-0.808), which was higher compared with experienced examiners (ICC, 0.167-0.672). The SEM (2.8°-4.4°) was less varied than that of experienced examiners (SEM, 3.8°-6.4°) for VE, but neither group's SEMs were clinically acceptable. Although minimal differences between intrarater and interrater reliability of GM and VE are noted, this study suggests that GM is more reliable than VE is when used by experienced examiners. These findings support the continued use of GM for first metatarsophalangeal joint dorsiflexion assessment.

  5. THREaD Mapper Studio: a novel, visual web server for the estimation of genetic linkage maps.

    Science.gov (United States)

    Cheema, Jitender; Ellis, T H Noel; Dicks, Jo

    2010-07-01

    The estimation of genetic linkage maps is a key component in plant and animal research, providing both an indication of the genetic structure of an organism and a mechanism for identifying candidate genes associated with traits of interest. Because of this importance, several computational solutions to genetic map estimation exist, mostly implemented as stand-alone software packages. However, the estimation process is often largely hidden from the user. Consequently, problems such as a program crashing may occur that leave a user baffled. THREaD Mapper Studio (http://cbr.jic.ac.uk/threadmapper) is a new web site that implements a novel, visual and interactive method for the estimation of genetic linkage maps from DNA markers. The rationale behind the web site is to make the estimation process as transparent and robust as possible, while also allowing users to use their expert knowledge during analysis. Indeed, the 3D visual nature of the tool allows users to spot features in a data set, such as outlying markers and potential structural rearrangements that could cause problems with the estimation procedure and to account for them in their analysis. Furthermore, THREaD Mapper Studio facilitates the visual comparison of genetic map solutions from third party software, aiding users in developing robust solutions for their data sets.

  6. Intra-arterial digital angiography of the liver

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Palma, L.; Stacul, F.; Maffessanti, M.; Pozzi-Mucelli, R.

    1983-08-01

    The authors report the preliminary results of the intraarterial digital angiography of the liver. A series of 30 patients were examined comparing conventional and digital technique following the injection of the coeliac, splenic, hepatic and mesenteric arteries. The results obtained with the digital technique have been of good quality and sometimes even better in spite of significant dilution of the contrast medium. It is concluded that intraarterial digital angiography of the liver gives some advantages compared with the conventional technique, that is the use of a much lower concentrated contrast medium, the better visualization of the portal branches and its collaterals and the very low cost of the film material.

  7. Determination of plate waste in primary school lunches by weighing and visual estimation methods: a validation study.

    Science.gov (United States)

    Liz Martins, Margarida; Cunha, Luís M; Rodrigues, Sara S P; Rocha, Ada

    2014-08-01

    The aim of this study was to validate the visual estimation method for aggregated plate waste of main dish at Portuguese primary school canteens. For this purpose plate waste at school lunch was measured for 505 individual servings, using weighing individual servings and plate waste and visual estimation method by a 6-point scale, as developed by Comstock et al. (1981). A high variability of initial serving weights was found with serving sizes ranging from 88.9 to 283.3g and with a coefficient of variation ranging from 5.5% to 24.7%. Mean plate waste was 27.5% according to the weighing method. There was a significant bias in the conversion of the visual waste estimations to actual waste, being overestimated by an average of 8.0 g (ranging from -12.9 g to 41.4 g). According to Bland and Altman plot, the mean difference between methods was of 8.0 g and the amplitude interval was 102.6g. The study showed that the visual estimation method is not as accurate as the weighing method in assessing nonselective aggregated plate waste at primary school canteens. Our findings are thus very important on considering plate waste assessment, since the wide variation on initial servings introduces a relevant bias when considering standard portions or a random sample of initial servings. Although, greater convenience, time-saving and the possibility to monitor plate waste of large groups, make the visual estimation method an important method to assess plate waste at school canteens, these results highlighted the need of portions standardization and control of initial servings to allow for its use. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. 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.)

  9. Soft tissue navigation for laparoscopic prostatectomy: evaluation of camera pose estimation for enhanced visualization

    Science.gov (United States)

    Baumhauer, M.; Simpfendörfer, T.; Schwarz, R.; Seitel, M.; Müller-Stich, B. P.; Gutt, C. N.; Rassweiler, J.; Meinzer, H.-P.; Wolf, I.

    2007-03-01

    We introduce a novel navigation system to support minimally invasive prostate surgery. The system utilizes transrectal ultrasonography (TRUS) and needle-shaped navigation aids to visualize hidden structures via Augmented Reality. During the intervention, the navigation aids are segmented once from a 3D TRUS dataset and subsequently tracked by the endoscope camera. Camera Pose Estimation methods directly determine position and orientation of the camera in relation to the navigation aids. Accordingly, our system does not require any external tracking device for registration of endoscope camera and ultrasonography probe. In addition to a preoperative planning step in which the navigation targets are defined, the procedure consists of two main steps which are carried out during the intervention: First, the preoperatively prepared planning data is registered with an intraoperatively acquired 3D TRUS dataset and the segmented navigation aids. Second, the navigation aids are continuously tracked by the endoscope camera. The camera's pose can thereby be derived and relevant medical structures can be superimposed on the video image. This paper focuses on the latter step. We have implemented several promising real-time algorithms and incorporated them into the Open Source Toolkit MITK (www.mitk.org). Furthermore, we have evaluated them for minimally invasive surgery (MIS) navigation scenarios. For this purpose, a virtual evaluation environment has been developed, which allows for the simulation of navigation targets and navigation aids, including their measurement errors. Besides evaluating the accuracy of the computed pose, we have analyzed the impact of an inaccurate pose and the resulting displacement of navigation targets in Augmented Reality.

  10. Estimation of utility values from visual analog scale measures of health in patients undergoing cardiac surgery

    Directory of Open Access Journals (Sweden)

    Oddershede L

    2014-01-01

    Full Text Available Lars Oddershede,1,2 Jan Jesper Andreasen,1 Lars Ehlers2 1Department of Cardiothoracic Surgery, Center for Cardiovascular Research, Aalborg University Hospital, Aalborg, Denmark; 2Danish Center for Healthcare Improvements, Faculty of Social Sciences and Faculty of Health Sciences, Aalborg University, Aalborg East, Denmark Introduction: In health economic evaluations, mapping can be used to estimate utility values from other health outcomes in order to calculate quality adjusted life-years. Currently, no methods exist to map visual analog scale (VAS scores to utility values. This study aimed to develop and propose a statistical algorithm for mapping five dimensions of health, measured on VASs, to utility scores in patients suffering from cardiovascular disease. Methods: Patients undergoing coronary artery bypass grafting at Aalborg University Hospital in Denmark were asked to score their health using the five VAS items (mobility, self-care, ability to perform usual activities, pain, and presence of anxiety or depression and the EuroQol 5 Dimensions questionnaire. Regression analysis was used to estimate four mapping models from patients' age, sex, and the self-reported VAS scores. Prediction errors were compared between mapping models and on subsets of the observed utility scores. Agreement between predicted and observed values was assessed using Bland–Altman plots. Results: Random effects generalized least squares (GLS regression yielded the best results when quadratic terms of VAS scores were included. Mapping models fitted using the Tobit model and censored least absolute deviation regression did not appear superior to GLS regression. The mapping models were able to explain approximately 63%–65% of the variation in the observed utility scores. The mean absolute error of predictions increased as the observed utility values decreased. Conclusion: We concluded that it was possible to predict utility scores from VAS scores of the five

  11. 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

  12. Estimating mast production: an evaluation of visual surveys and comparison with seed traps using white oaks

    Science.gov (United States)

    Roger W. Perry; Ronald E. Thill

    1999-01-01

    Perry and Thill compared five types of visual mast surveyed with seed trap data from 105 white oaks (Quercus alba L.) during 1996-1997 in the Ouachita Mountains of Arkansas. They also evaluated these visual survey methods for their usefulness in detecting differences in acorn density among areas. Indices derived from all five methods were highly...

  13. Spontaneous coronary artery dissection: challenges of coronary computed tomography angiography.

    Science.gov (United States)

    Eleid, Mackram F; Tweet, Marysia S; Young, Phillip M; Williamson, Eric; Hayes, Sharonne N; Gulati, Rajiv

    2017-01-01

    There is limited understanding of the role of cardiac computed tomography angiography (CCTA) for assessment of patients with spontaneous coronary artery dissection (SCAD). In this report we describe the diagnostic utility of CCTA in three young women presenting with signs and symptoms of myocardial ischemia who were eventually diagnosed with SCAD. None of the women had traditional atherosclerotic risk factors. SCAD was not initially identified on CCTA in any of the three women, but was visualized during retrospective analysis in two patients after invasive coronary angiography. In two patients follow-up CCTA imaging was used successfully for subsequent management. In patients presenting with signs or symptoms of acute coronary syndrome, SCAD may be missed or not detectable on CCTA. A negative CCTA should not exclude a diagnosis of SCAD, and invasive coronary angiography should be considered for further evaluation.

  14. Determination of left ventricular heart volume by fast MRI in breath-hold technique: how different are quantitative ventricular angiography, quantitative MRI, and visual echocardiography?; Linksventrikulaere Herzvoluminabestimmung mittels schneller MRT in Atemanhaltetechnik: Wie unterschiedlich sind quantitativer Herzkatheter, quantitativer MRT und visuelle Echokardiographie?

    Energy Technology Data Exchange (ETDEWEB)

    Rominger, M.B.; Bachmann, G.F. [Giessen Univ. (Germany). Diagnostische Radiologie; Kerckhoff-Klinik GmbH, Bad Nauheim (Germany). Projektgruppe Magnetresonanztomographie; Pabst, W. [Giessen Univ. (Germany). Inst. fuer Medizinische Informatik; Ricken, W.W. [Kerckhoff-Klinik GmbH, Bad Nauheim (Germany). Projektgruppe Magnetresonanztomographie; Dinkel, H.P.; Rau, W.S. [Giessen Univ. (Germany). Diagnostische Radiologie

    2000-01-01

    Goal: Comparison of fast MRI, echocardiography (Echo), and ventricular angiography (Cath) in the assessment of left ventricular global function. Methods: Fast MRI in short axis plane, biplane Cath, and 2D Echo were performed in 62 patients [35 coronary artery diseases, 16 acquired valvular diseases (VD), 9 dilated cardiomyopathies (DCM), 1 congenital heart disease and 1 heart transplantation]. Enddiastolic (EDV), endsystolic (ESV), stroke volumes (SV), cardiac output (CO), and ejection fraction (EF) were compared in MRI and Cath. EF was visually estimated in 2D Echo by an experienced observer. Results: In comparison to MRI, Cath overestimated EF by 8.4%, and Echo underestimated EF by 5.6%. The limits of agreement between MRI and Cath in EF were {+-}23.8%, between MRI and Echo {+-}18%, and between Echo and Cath {+-}19.4%. Significant differences were found between Cath and MRI in EDV, SV, and CO, but not for ESV. The best agreement in EF was found in the group with DCM, the worst in the group with VD. Conclusion: Important systemic and random errors were found in the comparison of MRI, Echo, and Cath. For therapy decision and follow-up, the methods should not be exchanged unscrupulously. (orig.) [German] Ziel: Methodenvergleich von schneller Magnetresonanztomographie (MRT), Echokardiographie (Echo) und Herzkatheter (HK) in der Bestimmung linksventrikulaerer globaler Funktionsparameter. Material und Methoden: Bei 62 Patienten (35 koronare Herzerkrankungen, 16 Herzklappenvitien (KV), 9 idiopathische dilatative Kardiomyopathien (DCM), 1 kongenitale Herzerkrankung und 1 Herzktransplantation) wurde ein Methodenvergleich zwischen schneller Cine MRT im Kurzachsenschnitt, biplanarem HK und 2D Echo durchgefuehrt. Verglichen wurden in MRT und HK linksventrikulaeres enddiastolisches (EDV) und endsystolisches Volumen (ESV), Schlagvolumen (SV), Herzzeitvolumen (HZV) und Ejektionsfraktion (EF). In der Echo wurde die EF visuell durch einen erfahrenen Untersucher bestimmt

  15. Validation of visual estimation of portion size consumed as a method for estimating food intake by young Indian children.

    Science.gov (United States)

    Dhingra, Pratibha; Sazawa, Sunil; Menon, Venugopal P; Dhingra, Usha; Black, Robert E

    2007-03-01

    In this observational study, estimation of food intake was evaluated using recording of portion size consumed, instead of post-weighing, as a method. In total, 930 feeding episodes were observed among 128 children aged 12-24 months in which actual intake was available by pre- and post-weighing. For each offering and feeding episode, portion size consumed was recorded by an independent nutritionist-as none, less than half, half or more, and all. Using the pre-weighed offering, available intake was estimated by multiplying portion sizes by the estimated weight. The estimated mean intake was 510.4 kilojoules compared to actual intake of 510.7 kilojoules by weighing. Similar results were found with nestum (52.0 vs 56.2 g), bread (3.8 vs 3.7 g), puffed rice (1.7 vs 1.9 g), banana (31.3 vs 24.4 g), and milk (41.6 vs 44.2 mL). Recording portion size consumed and estimating food intake from that provides a good alternative to the time-consuming and often culturally-unacceptable method of post-weighing food each time after a feeding episode.

  16. 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.

  17. Movement-based estimation and visualization of space use in 3D for wildlife ecology and conservation.

    Directory of Open Access Journals (Sweden)

    Jeff A Tracey

    Full Text Available Advances in digital biotelemetry technologies are enabling the collection of bigger and more accurate data on the movements of free-ranging wildlife in space and time. Although many biotelemetry devices record 3D location data with x, y, and z coordinates from tracked animals, the third z coordinate is typically not integrated into studies of animal spatial use. Disregarding the vertical component may seriously limit understanding of animal habitat use and niche separation. We present novel movement-based kernel density estimators and computer visualization tools for generating and exploring 3D home ranges based on location data. We use case studies of three wildlife species--giant panda, dugong, and California condor--to demonstrate the ecological insights and conservation management benefits provided by 3D home range estimation and visualization for terrestrial, aquatic, and avian wildlife research.

  18. Movement-based estimation and visualization of space use in 3D for wildlife ecology and conservation.

    Science.gov (United States)

    Tracey, Jeff A; Sheppard, James; Zhu, Jun; Wei, Fuwen; Swaisgood, Ronald R; Fisher, Robert N

    2014-01-01

    Advances in digital biotelemetry technologies are enabling the collection of bigger and more accurate data on the movements of free-ranging wildlife in space and time. Although many biotelemetry devices record 3D location data with x, y, and z coordinates from tracked animals, the third z coordinate is typically not integrated into studies of animal spatial use. Disregarding the vertical component may seriously limit understanding of animal habitat use and niche separation. We present novel movement-based kernel density estimators and computer visualization tools for generating and exploring 3D home ranges based on location data. We use case studies of three wildlife species--giant panda, dugong, and California condor--to demonstrate the ecological insights and conservation management benefits provided by 3D home range estimation and visualization for terrestrial, aquatic, and avian wildlife research.

  19. Movement-based estimation and visualization of space use in 3D for wildlife ecology and conservation

    Science.gov (United States)

    Tracey, Jeff A.; Sheppard, James; Zhu, Jun; Wei, Fu-Wen; Swaisgood, Ronald R.; Fisher, Robert N.

    2014-01-01

    Advances in digital biotelemetry technologies are enabling the collection of bigger and more accurate data on the movements of free-ranging wildlife in space and time. Although many biotelemetry devices record 3D location data with x, y, and z coordinates from tracked animals, the third z coordinate is typically not integrated into studies of animal spatial use. Disregarding the vertical component may seriously limit understanding of animal habitat use and niche separation. We present novel movement-based kernel density estimators and computer visualization tools for generating and exploring 3D home ranges based on location data. We use case studies of three wildlife species – giant panda, dugong, and California condor – to demonstrate the ecological insights and conservation management benefits provided by 3D home range estimation and visualization for terrestrial, aquatic, and avian wildlife research.

  20. 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)

  1. Effects of shape, size, and chromaticity of stimuli on estimated size in normally sighted, severely myopic, and visually impaired students.

    Science.gov (United States)

    Huang, Kuo-Chen; Wang, Hsiu-Feng; Chen, Chun-Ching

    2010-06-01

    Effects of shape, size, and chromaticity of stimuli on participants' errors when estimating the size of simultaneously presented standard and comparison stimuli were examined. 48 Taiwanese college students ages 20 to 24 years old (M = 22.3, SD = 1.3) participated. Analysis showed that the error for estimated size was significantly greater for those in the low-vision group than for those in the normal-vision and severe-myopia groups. The errors were significantly greater with green and blue stimuli than with red stimuli. Circular stimuli produced smaller mean errors than did square stimuli. The actual size of the standard stimulus significantly affected the error for estimated size. Errors for estimations using smaller sizes were significantly higher than when the sizes were larger. Implications of the results for graphics-based interface design, particularly when taking account of visually impaired users, are discussed.

  2. Clinical application of pelvic MR angiography for gynecologic diseases

    International Nuclear Information System (INIS)

    Ohnishi, Takeshi

    1996-01-01

    Magnetic resonance (MR) imaging is the second most important method next to the ultrasound for the diagnosis of gynecological disorders. MR angiography provides a new noninvasive method for evaluating vascular occlusive disease of the lower extremities and the branches of abdominal aorta. To our knowledge, no determinant of efficacy of MR angiography and images of gynecological diseases have yet been made. Maximum intensity projection image was obtained from the data set by the three dimensional contrast enhanced MR angiography (3D-CE MRA) with newly designed fat suppression method. MR angiogram reveals well visualization of lower abdominal aorta and its branches. Furthermore, uterine arteries were identified in 49.3% of the cases, branching from the internal iliac artery. Leiomyoma of the uterus showed an enhanced uterus in 53.7% of the eases. All cases of endometriosis demonstrated a homogeneous, high signal intensity being a specific finding. In conclusion, maximum intensity projection image of pelvis showed a good visualization of the lower abdominal aorta and its branches. Uterine artery and, in a few cases, ovarian artery can be demonstrated on MR angiography. All cases of endometriosis showed a significant, high signal intensity. This technique is noninvasive and be a supplementary method for diagnosis and follow up of vasculature of gynecological disorders. (author)

  3. On-board and Ground Visual Pose Estimation Techniques for UAV Control

    OpenAIRE

    Martínez Luna, Carol Viviana; Mondragon Bernal, Ivan Fernando; Olivares Méndez, Miguel Ángel; Campoy Cervera, Pascual

    2011-01-01

    In this paper, two techniques to control UAVs (Unmanned Aerial Vehicles), based on visual information are presented. The first one is based on the detection and tracking of planar structures from an on-board camera, while the second one is based on the detection and 3D reconstruction of the position of the UAV based on an external camera system. Both strategies are tested with a VTOL (Vertical take-off and landing) UAV, and results show good behavior of the visual systems (precision in the es...

  4. 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.

  5. Preoperative evaluation of the artery of adamkiewicz by MR angiography and CT angiography in patients with a thoracic aortic aneurysm

    International Nuclear Information System (INIS)

    Niinuma, Hiroyuki; Ohira, Atsushi; Makita, Shinji; Moriai, Yoshiteru; Hiramori, Katsuhiko; Yoshioka, Kunihiro; Nakajima, Takayuki; Kawazoe, Kohei

    2002-01-01

    Paraplegia is known as an extremely serious and important complication of surgical repair in patients with a thoraco-abdominal aortic aneurysm. It is important to evaluate the artery of Adamkiewicz (AdA) before surgical repair to prevent paraplegia. But the AdA is difficult to visualize by the invasive and hazardous, conventional selective angiography. The aim of this study was to visualize AdA by MR angiography (MRA) and CT angiography (CTA). Twenty-one consecutive patients with a thoracic aortic aneurysm underwent both gadolinium-enhanced, three-dimensional MRA and CTA using multislice helical CT. The AdA was successfully visualized in 15 of the 21 patients (71.4%) by MRA, and in 17 of those 21 patients (80.9%) by CTA. Its continuity was depicted in 12 of 15 patients (80%) by MRA, and in 9 of 17 patients (47%) by CTA. AdA was visualized at 85.7% by MRA or CTA, respectively. This study shows that CTA is a much more sensitive method to detect AdA than MRA. On the other hand, MRA is better to evaluate the continuity of AdA from the descending aorta to the anterior spinal artery, than CTA. Therefore, MRA and CTA are both useful for a preoperative evaluation of AdA and its detailed vascular anatomy from the aorta to the anterior spinal artery. (author)

  6. Magnetic resonance angiography of fetal vasculature at 3.0 T.

    Science.gov (United States)

    Neelavalli, Jaladhar; Krishnamurthy, Uday; Jella, Pavan K; Mody, Swati S; Yadav, Brijesh K; Hendershot, Kelly; Hernandez-Andrade, Edgar; Yeo, Lami; Cabrera, Maria D; Haacke, Ewart M; Hassan, Sonia S; Romero, Roberto

    2016-12-01

    Magnetic resonance angiography has not been used much previously for visualizing fetal vessels in utero for reasons that include a contraindication for the use of exogenous contrast agents, maternal respiratory motion and fetal motion. In this work, we report the feasibility of using an appropriately modified clinical time-of-flight magnetic resonance imaging sequence for non-contrast angiography of human fetal and placental vessels at 3.0 T. Using this 2D angiography technique, it is possible to visualize fetal vascular networks in late pregnancy. • 3D-visualization of fetal vasculature is feasible using non-contrast MRA at 3.0 T. • Visualization of placental vasculature is also possible with this method. • Fetal MRA can serve as a vascular localizer for quantitative MRI studies. • This method can be extended to 1.5 T.

  7. Proactive interference does not meaningfully distort visual working memory capacity estimates in the canonical change detection task

    Directory of Open Access Journals (Sweden)

    Po-Han eLin

    2012-02-01

    Full Text Available The change detection task has become a standard method for estimating the storage capacity of visual working memory. Most researchers assume that this task isolates the properties of an active short-term storage system that can be dissociated from long-term memory systems. However, long-term memory storage may influence performance on this task. In particular, memory traces from previous trials may create proactive interference that sometimes leads to errors, thereby reducing estimated capacity. Consequently, the capacity of visual working memory may be higher than is usually thought, and correlations between capacity and other measures of cognition may reflect individual differences in proactive interference rather than individual differences in the capacity of the short-term storage system. Indeed, previous research has shown that change detection performance can be influenced by proactive interference under some conditions. The purpose of the present study was to determine whether the canonical version of the change detection task—in which the to-be-remembered information consists of simple, briefly presented features—is influenced by proactive interference. Two experiments were conducted using methods that ordinarily produce substantial evidence of proactive interference, but no proactive interference was observed. Thus, the canonical version of the change detection task can be used to assess visual working memory capacity with no meaningful influence of proactive interference.

  8. Novel application of postmortem CT angiography for evaluation of the intracranial vascular anatomy in cadaver heads

    NARCIS (Netherlands)

    Van Eijk, Ruben P A; Van Der Zwan, Albert; Bleys, Ronald L A W; Regli, Luca; Esposito, Giuseppe

    2015-01-01

    OBJECTIVE. Postmortem CT angiography is a common procedure used to visualize the entire human vasculature. For visualization of a specific organ's vascular anatomy, casting is the preferred method. Because of the permanent and damaging nature of casting, the organ cannot be further used as an

  9. 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)

  10. Validation of an efficient visual method for estimating leaf area index ...

    African Journals Online (AJOL)

    Leaf area index (LAI) is a key ecophysiological parameter in forest stands because it characterises the interface between atmospheric processes and plant physiology. Several indirect methods for estimating LAI have been developed. However, these methods have limitations that can affect the estimates. This study aimed ...

  11. 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

  12. 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.

  13. 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 ...

  14. 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)

  15. Assessment of anemia during CT pulmonary angiography

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-15

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

  16. 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.

  17. Improving slowness estimate stability and visualization using limited sensor pair correlation on seismic arrays

    Science.gov (United States)

    Gibbons, Steven J.; Näsholm, S. P.; Ruigrok, E.; Kværna, T.

    2018-04-01

    Seismic arrays enhance signal detection and parameter estimation by exploiting the time-delays between arriving signals on sensors at nearby locations. Parameter estimates can suffer due to both signal incoherence, with diminished waveform similarity between sensors, and aberration, with time-delays between coherent waveforms poorly represented by the wave-front model. Sensor-to-sensor correlation approaches to parameter estimation have an advantage over direct beamforming approaches in that individual sensor-pairs can be omitted without necessarily omitting entirely the data from each of the sensors involved. Specifically, we can omit correlations between sensors for which signal coherence in an optimal frequency band is anticipated to be poor or for which anomalous time-delays are anticipated. In practice, this usually means omitting correlations between more distant sensors. We present examples from International Monitoring System seismic arrays with poor parameter estimates resulting when classical f-k analysis is performed over the full array aperture. We demonstrate improved estimates and slowness grid displays using correlation beamforming restricted to correlations between sufficiently closely spaced sensors. This limited sensor-pair correlation (LSPC) approach has lower slowness resolution than would ideally be obtained by considering all sensor-pairs. However, this ideal estimate may be unattainable due to incoherence and/or aberration and the LSPC estimate can often exploit all channels, with the associated noise-suppression, while mitigating the complications arising from correlations between very distant sensors. The greatest need for the method is for short-period signals on large aperture arrays although we also demonstrate significant improvement for secondary regional phases on a small aperture array. LSPC can also provide a robust and flexible approach to parameter estimation on three-component seismic arrays.

  18. Ankle joint range of motion measurements in spastic cerebral palsy children: intraobserver and interobserver reliability and reproducibility of goniometry and visual estimation.

    Science.gov (United States)

    Allington, Nanni J; Leroy, Nathalie; Doneux, Carole

    2002-07-01

    The aim of this study was to assess the intra- and interobserver reliability and reproducibility of goniometry and visual estimation of ankle joint range of motion measurements in children with spastic cerebral palsy. Forty-six ankles of 24 spastic cerebral palsy children were measured under a strict protocol. The global mean measurement error was 5 degrees (SD, 5 degrees) for intra- and interobserver measurements and 3 degrees (SD, 3 degrees) for goniometry versus visual estimation. Statistical analysis showed a high reliability for intra- and interobserver measurements (r>0.75), between visual estimation and goniometry (correlation coefficient, r>0.967; concordance coefficient, r>0.957). Both visual estimation and goniometry ankle range-of-motion measurements are reliable and reproducible in spastic cerebral palsy children if a strict but simple protocol is applied.

  19. Individual patient data meta-analysis for the clinical assessment of coronary computed tomography angiography: protocol of the Collaborative Meta-Analysis of Cardiac CT (CoMe-CCT

    Directory of Open Access Journals (Sweden)

    Schuetz Georg M

    2013-02-01

    Full Text Available Abstract Background Coronary computed tomography angiography has become the foremost noninvasive imaging modality of the coronary arteries and is used as an alternative to the reference standard, conventional coronary angiography, for direct visualization and detection of coronary artery stenoses in patients with suspected coronary artery disease. Nevertheless, there is considerable debate regarding the optimal target population to maximize clinical performance and patient benefit. The most obvious indication for noninvasive coronary computed tomography angiography in patients with suspected coronary artery disease would be to reliably exclude significant stenosis and, thus, avoid unnecessary invasive conventional coronary angiography. To do this, a test should have, at clinically appropriate pretest likelihoods, minimal false-negative outcomes resulting in a high negative predictive value. However, little is known about the influence of patient characteristics on the clinical predictive values of coronary computed tomography angiography. Previous regular systematic reviews and meta-analyses had to rely on limited summary patient cohort data offered by primary studies. Performing an individual patient data meta-analysis will enable a much more detailed and powerful analysis and thus increase representativeness and generalizability of the results. The individual patient data meta-analysis is registered with the PROSPERO database (CoMe-CCT, CRD42012002780. Methods/Design The analysis will include individual patient data from published and unpublished prospective diagnostic accuracy studies comparing coronary computed tomography angiography with conventional coronary angiography. These studies will be identified performing a systematic search in several electronic databases. Corresponding authors will be contacted and asked to provide obligatory and additional data. Risk factors, previous test results and symptoms of individual patients will be

  20. Individual patient data meta-analysis for the clinical assessment of coronary computed tomography angiography: protocol of the Collaborative Meta-Analysis of Cardiac CT (CoMe-CCT).

    Science.gov (United States)

    Schuetz, Georg M; Schlattmann, Peter; Achenbach, Stephan; Budoff, Matthew; Garcia, Mario J; Roehle, Robert; Pontone, Gianluca; Meijboom, Willem Bob; Andreini, Daniele; Alkadhi, Hatem; Honoris, Lily; Bettencourt, Nuno; Hausleiter, Jörg; Leschka, Sebastian; Gerber, Bernhard L; Meijs, Matthijs Fl; Shabestari, Abbas Arjmand; Sato, Akira; Zimmermann, Elke; Schoepf, Uwe J; Diederichsen, Axel; Halon, David A; Mendoza-Rodriguez, Vladimir; Hamdan, Ashraf; Nørgaard, Bjarne L; Brodoefel, Harald; Ovrehus, Kristian A; Jenkins, Shona Mm; Halvorsen, Bjørn A; Rixe, Johannes; Sheikh, Mehraj; Langer, Christoph; Martuscelli, Eugenio; Romagnoli, Andrea; Scholte, Arthur Jha; Marcus, Roy P; Ulimoen, Geir R; Nieman, Koen; Mickley, Hans; Nikolaou, Konstantin; Tardif, Jean-Claude; Johnson, Thorsten Rc; Muraglia, Simone; Chow, Benjamin Jw; Maintz, David; Laule, Michael; Dewey, Marc

    2013-02-15

    Coronary computed tomography angiography has become the foremost noninvasive imaging modality of the coronary arteries and is used as an alternative to the reference standard, conventional coronary angiography, for direct visualization and detection of coronary artery stenoses in patients with suspected coronary artery disease. Nevertheless, there is considerable debate regarding the optimal target population to maximize clinical performance and patient benefit. The most obvious indication for noninvasive coronary computed tomography angiography in patients with suspected coronary artery disease would be to reliably exclude significant stenosis and, thus, avoid unnecessary invasive conventional coronary angiography. To do this, a test should have, at clinically appropriate pretest likelihoods, minimal false-negative outcomes resulting in a high negative predictive value. However, little is known about the influence of patient characteristics on the clinical predictive values of coronary computed tomography angiography. Previous regular systematic reviews and meta-analyses had to rely on limited summary patient cohort data offered by primary studies. Performing an individual patient data meta-analysis will enable a much more detailed and powerful analysis and thus increase representativeness and generalizability of the results. The individual patient data meta-analysis is registered with the PROSPERO database (CoMe-CCT, CRD42012002780). The analysis will include individual patient data from published and unpublished prospective diagnostic accuracy studies comparing coronary computed tomography angiography with conventional coronary angiography. These studies will be identified performing a systematic search in several electronic databases. Corresponding authors will be contacted and asked to provide obligatory and additional data. Risk factors, previous test results and symptoms of individual patients will be used to estimate the pretest likelihood of coronary

  1. 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 ...

  2. 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

  3. Estimating cohesion in small groups using audio-visual nonverbal behavior

    NARCIS (Netherlands)

    Hung, H.; Gatica-Perez, D.

    2010-01-01

    Cohesiveness in teams is an essential part of ensuring the smooth running of task-oriented groups. Research in social psychology and management has shown that good cohesion in groups can be correlated with team effectiveness or productivity, so automatically estimating group cohesion for team

  4. Particle Filter-based Estimation of Orbital Parameters of Visual Binary Stars with Incomplete Observations

    Science.gov (United States)

    Claveria, R.; Mendez, R. A.; Orchard, M.

    2018-01-01

    This work addresses the problem of orbital estimation from a Bayesian point of view, using the Particle Filter technique to approximate the posterior distribution of orbital parameters. Additionally, we present a multiple imputation scheme as a means to include partial measurements into the analysis.

  5. Estimation of mental effort in learning visual search by measuring pupil response.

    Directory of Open Access Journals (Sweden)

    Tatsuto Takeuchi

    Full Text Available Perceptual learning refers to the improvement of perceptual sensitivity and performance with training. In this study, we examined whether learning is accompanied by a release from mental effort on the task, leading to automatization of the learned task. For this purpose, we had subjects conduct a visual search for a target, defined by a combination of orientation and spatial frequency, while we monitored their pupil size. It is well known that pupil size reflects the strength of mental effort invested in a task. We found that pupil size increased rapidly as the learning proceeded in the early phase of training and decreased at the later phase to a level half of its maximum value. This result does not support the simple automatization hypothesis. Instead, it suggests that the mental effort and behavioral performance reflect different aspects of perceptual learning. Further, mental effort would be continued to be invested to maintain good performance at a later stage of training.

  6. Contrast-enhanced magnetic resonance angiography of persistent fifth aortic arch in children

    International Nuclear Information System (INIS)

    Zhong, Yumin; Zhu, Ming; Sun, Aimin; Li, Yuhua; Jaffe, Richard B.; Gao, Wei

    2007-01-01

    Cine angiography and echocardiography have been utilized to diagnose congenital aortic arch anomalies. However, the visualization of great vessels by echocardiography is limited, while cine angiography requires cardiac catheterization with ionizing radiation. Contrast-enhanced magnetic resonance angiography (MRA) is a noninvasive modality suitable for visualization of congenital aortic arch anomalies. To evaluate the utility of contrast-enhanced MRA in the diagnosis of persistent fifth aortic arch, a rare congenital aortic arch anomaly, and to compare the diagnostic accuracy of MRA with that of echocardiography and cine angiography. In four pediatric patients, contrast-enhanced MRA studies were performed for diagnosing persistent fifth aortic arch. The findings of MRA were compared with echocardiographic findings and confirmed by cine angiography and operation. Transthoracic surface echocardiography noted an aberrant vessel arising from the ascending aorta in two of four patients; the etiology of this vessel was uncertain. In the other two patients a diagnosis of coarctation was made. Of the four patients, only one was diagnosed with interruption of the aortic arch. Contrast-enhanced MRA clarified uncertain echocardiographic findings, enabling the correct diagnosis of persistent fifth aortic arch with fourth aortic arch interruption in all four patients. Contrast-enhanced MRA is a safe, accurate, and fast imaging technique for the evaluation of persistent fifth aortic arch and may obviate the need for conventional cine angiography. Cardiac catheterization may be reserved for some types of complicated congenital heart disease and for obtaining hemodynamic information. (orig.)

  7. A robust method for estimating motorbike count based on visual information learning

    Science.gov (United States)

    Huynh, Kien C.; Thai, Dung N.; Le, Sach T.; Thoai, Nam; Hamamoto, Kazuhiko

    2015-03-01

    Estimating the number of vehicles in traffic videos is an important and challenging task in traffic surveillance, especially with a high level of occlusions between vehicles, e.g.,in crowded urban area with people and/or motorbikes. In such the condition, the problem of separating individual vehicles from foreground silhouettes often requires complicated computation [1][2][3]. Thus, the counting problem is gradually shifted into drawing statistical inferences of target objects density from their shape [4], local features [5], etc. Those researches indicate a correlation between local features and the number of target objects. However, they are inadequate to construct an accurate model for vehicles density estimation. In this paper, we present a reliable method that is robust to illumination changes and partial affine transformations. It can achieve high accuracy in case of occlusions. Firstly, local features are extracted from images of the scene using Speed-Up Robust Features (SURF) method. For each image, a global feature vector is computed using a Bag-of-Words model which is constructed from the local features above. Finally, a mapping between the extracted global feature vectors and their labels (the number of motorbikes) is learned. That mapping provides us a strong prediction model for estimating the number of motorbikes in new images. The experimental results show that our proposed method can achieve a better accuracy in comparison to others.

  8. Clinical Assessment of a New Stereoscopic Digital Angiography System

    International Nuclear Information System (INIS)

    Moll, Thierry; Douek, Philippe; Finet, Gerard; Turjman, Francis; Picard, Catherine; Revel, Didier; Amiel, Michel

    1998-01-01

    Purpose: To assess the clinical feasibility of an experimental modified angiographic system capable of real-time digital stereofluoroscopy and stereography in X-ray angiography, using a twin-focus tube and a stereoscopic monitor. Methods: We report the experience obtained in 37 patients with a well-documented examination. The patients were examined for coronary angiography (11 cases), aortography (7 cases), pulmonary angiography (6 cases), inferior vena cava filter placement (2 cases), and cerebral angiography (11 cases). Six radiologists were asked to use stereoscopic features for fluoroscopy and angiography. A questionnaire was designed to record their subjective evaluation of stereoscopic image quality, ergonomics of the system, and its medical interest. Results: Stereofluoroscopy was successfully used in 25 of 37 cases; diplopia and/or ghost images were reported in 6 cases. It was helpful for aortic catheterization in 10 cases and for selective catheterization in 5 cases. In stereoangiography, depth was easily and accurately perceived in 27 of 37 cases; diplopia and/or ghost images were reported in 4 cases. A certain gain in the three-dimensional evaluation of the anatomy and relation between vessels and lesions was noted. As regards ergonomic considerations, polarized spectacles were not considered cumbersome. Visual fatigue and additional work were variously reported. Stereoshift tuning before X-ray acquisition was not judged to be a limiting factor. Conclusion: A twin-focus X-ray tube and a polarized shutter for stereoscopic display allowed effective real-time three-dimensional perception of angiographic images. Our clinical study suggests no clear medical interest for diagnostic examinations, but the field of interventional radiology needs to be investigated

  9. A dual systems account of visual perception: Predicting candy consumption from distance estimates.

    Science.gov (United States)

    Krpan, Dario; Schnall, Simone

    2017-04-01

    A substantial amount of evidence shows that visual perception is influenced by forces that control human actions, ranging from motivation to physiological potential. However, studies have not yet provided convincing evidence that perception itself is directly involved in everyday behaviors such as eating. We suggest that this issue can be resolved by employing the dual systems account of human behavior. We tested the link between perceived distance to candies and their consumption for participants who were tired or depleted (impulsive system), versus those who were not (reflective system). Perception predicted eating only when participants were tired (Experiment 1) or depleted (Experiments 2 and 3). In contrast, a rational determinant of behavior-eating restraint towards candies-predicted eating for non-depleted individuals (Experiment 2). Finally, Experiment 3 established that perceived distance was correlated with participants' self-reported motivation to consume candies. Overall, these findings suggest that the dynamics between perception and behavior depend on the interplay of the two behavioral systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Comparison of dual-axis rotational coronary angiography (XPERSWING) versus conventional technique in routine practice.

    Science.gov (United States)

    Gómez-Menchero, Antonio E; Díaz, José F; Sánchez-González, Carlos; Cardenal, Rosa; Sanghvi, Amit B; Roa-Garrido, Jessica; Rodríguez-López, José L

    2012-05-01

    Coronary angiography is the gold standard for the study of coronary artery disease. This technique requires several orthogonal projections. Rotational angiography is a new technique which involves pre-set rotation of the X-ray tube around the patient and allows visualization of each coronary artery in different views, using a single contrast injection. The purpose of this study was to compare conventional coronary angiography (A) vs rotational angiography (B), focusing on radiation dose, amount of contrast administered, and total procedure time for both diagnostic and therapeutic percutaneous coronary interventions. Prospective study of 104 consecutive patients undergoing coronary angiography who were randomized to one of these techniques. We found a significant reduction in the amount of contrast administered (A vs B, 93.1 [41.7] vs 50.9 [14.7] mL; Protational angiography arm. However, when only the last 50 patients were analyzed, we found no difference in procedure time between the groups, probably related to the learning curve of the operators. Angioplasty was performed in 29 patients in group A and 28 patients in group B. Contrast reduction was maintained in the rotational angiography group compared to the conventional technique (A vs B, 335.1 [192.1] vs 238.5 [114.4] mL; P=.02). The rotational angiography technique leads to a significant decrease in radiation exposure and contrast dose administered for diagnostic procedures when compared to conventional coronary angiography. In patients who undergo percutaneous coronary intervention, contrast reduction remains significant. Copyright © 2011 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  11. Digital subtraction angiography in the assessment of cardiovascular disease

    International Nuclear Information System (INIS)

    Harrington, D.P.; Boxt, L.M.

    1985-01-01

    Digital subtraction angiography (DSA) is a new radiographic method for evaluating the cardiovascular system. It represents another in a continuing series of computer-assisted diagnostic imaging modalities. The advantages of this technique are its relatively noninvasive nature combined with diagnostically acceptable angiographic images of a variety of cardiovascular structures. Major clinical applications of DSA include its use in imaging of localized regions of peripheral arterial disease and as a screening procedure in evaluating extracranial carotid and vertebral artery disease and renovascular hypertension. Cardiac applications of DSA include assessment of ventricular function, recognition and quantification of intracardiac shunts, visualization of coronary artery bypass grafts, and the study of complex congenital cardiac malformations. Digital subtraction angiography may also be used to evaluate intracranial aneurysms and vascular tumors

  12. 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.

  13. Time and order estimation of paintings based on visual features and expert priors

    Science.gov (United States)

    Cabral, Ricardo S.; Costeira, João P.; de La Torre, Fernando; Bernardino, Alexandre; Carneiro, Gustavo

    2011-03-01

    Time and order are considered crucial information in the art domain, and subject of many research efforts by historians. In this paper, we present a framework for estimating the ordering and date information of paintings and drawings. We formulate this problem as the embedding into a one dimension manifold, which aims to place paintings far or close to each other according to a measure of similarity. Our formulation can be seen as a manifold learning algorithm, albeit properly adapted to deal with existing questions in the art community. To solve this problem, we propose an approach based in Laplacian Eigenmaps and a convex optimization formulation. Both methods are able to incorporate art expertise as priors to the estimation, in the form of constraints. Types of information include exact or approximate dating and partial orderings. We explore the use of soft penalty terms to allow for constraint violation to account for the fact that prior knowledge may contain small errors. Our problem is tested within the scope of the PrintART project, which aims to assist art historians in tracing Portuguese Tile art "Azulejos" back to the engravings that inspired them. Furthermore, we describe other possible applications where time information (and hence, this method) could be of use in art history, fake detection or curatorial treatment.

  14. Physical principles of cardiac digital subtraction angiography

    International Nuclear Information System (INIS)

    Buonocore, E.; Pavlicek, W.

    1986-01-01

    Advances in the applications of computers with standard radiologic equipment have resulted in the development of electronic, or so-called ''film-less'' imaging. This technique, discussed by the authors, has become of particular value in the visualization of the central vascular system and has become known as digital subtraction angiography (DSA). Commercial products have become increasingly available and are capable of converting T.V. signals, obtained by conventional fluorography, to a computed array of digital values. Addition, subtraction, and averaging of this data, result in images with adequate signal-to-noise ratios that achieve detection of low concentrations of contrast media not possible with conventional screen film techniques. Computer subtraction of unnecessary background information improves the conspicuity of the opacified vessels to permit detection of vascular structures containing a concentration of no more than 1-3 percent of contrast media. This improved visualization is possible even with intravenous peripheral injections or reduced amounts of contrast media given intraarterially. With either method of contrast media administration, DSDA has become an excellent means of anatomic demonstration of the heart and great vessels with decreased morbidity and at lower cost

  15. Global Estimates on the Number of People Blind or Visually Impaired by Diabetic Retinopathy: A Meta-analysis From 1990 to 2010.

    Science.gov (United States)

    Leasher, Janet L; Bourne, Rupert R A; Flaxman, Seth R; Jonas, Jost B; Keeffe, Jill; Naidoo, Kovin; Pesudovs, Konrad; Price, Holly; White, Richard A; Wong, Tien Y; Resnikoff, Serge; Taylor, Hugh R

    2016-09-01

    To estimate global and regional trends from 1990 to 2010 of the prevalence and number of persons visually impaired specifically by diabetic retinopathy (DR), as a complication of the precipitous trends in global diabetes, is fundamental for health planning purposes. The meta-analysis of published population studies from 1990 to 2012 for the Global Burden of Disease Study 2010 (GBD) yielded estimated global regional trends in DR among other causes of moderate and severe vision impairment (MSVI; presenting visual acuity visual acuity visually impaired people, 0.8 million were blind and 3.7 million were visually impaired because of DR, with an alarming increase of 27% and 64%, respectively, spanning the two decades from 1990 to 2010. DR accounted for 2.6% of all blindness in 2010 and 1.9% of all MSVI worldwide, increasing from 2.1% and 1.3%, respectively, in 1990. These figures were lower in regions with younger populations (4%). The number of persons with visual impairment due to DR worldwide is rising and represents an increasing proportion of all blindness/MSVI causes. Age-standardized prevalence of DR-related blindness/MSVI was higher in sub-Saharan Africa and South Asia. One out of 39 blind people had blindness due to DR, and 1 out of 52 visually impaired people had visual impairment due to DR. © 2016 by the American Diabetes Association.

  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. 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.

  18. Proposal of a non-lethal visual census method to estimate freshwater stingray abundance

    Directory of Open Access Journals (Sweden)

    Mónica Andrea Morales-Betancourt

    2016-01-01

    Full Text Available There is not a current method to estimate South American freshwater stingray’s abundance. Therefore we designed a census method and tested it in the field. It consists of making nocturnal surveys by boat in large rivers (>25m width and floodplain lagoons of varying sizes, along transects of 100m x 10m (1000 m2. We applied this method in the Tomo River, a tributary of the Orinoco River in Colombia. 110 transects were surveyed in 200 runs. A total of 149 rays of four species were recorded: Potamotrygon motoro, Potamotrygon orbignyi, Potamotrygon schroederi and Paratrygon aiereba. P. motoro was the most abundant with a density of 0.31 individuals /1000 m2 (SD=0.5. This method gave optimal results when applied to habitats with high transparency and shallow depth (< 1m since it permitted the identification of both adults and juveniles present.

  19. Does manipulating the speed of visual flow in virtual reality change distance estimation while walking in Parkinson's disease?

    Science.gov (United States)

    Ehgoetz Martens, Kaylena A; Ellard, Colin G; Almeida, Quincy J

    2015-03-01

    Although dopaminergic replacement therapy is believed to improve sensory processing in PD, while delayed perceptual speed is thought to be caused by a predominantly cholinergic deficit, it is unclear whether sensory-perceptual deficits are a result of corrupt sensory processing, or a delay in updating perceived feedback during movement. The current study aimed to examine these two hypotheses by manipulating visual flow speed and dopaminergic medication to examine which influenced distance estimation in PD. Fourteen PD and sixteen HC participants were instructed to estimate the distance of a remembered target by walking to the position the target formerly occupied. This task was completed in virtual reality in order to manipulate the visual flow (VF) speed in real time. Three conditions were carried out: (1) BASELINE: VF speed was equal to participants' real-time movement speed; (2) SLOW: VF speed was reduced by 50 %; (2) FAST: VF speed was increased by 30 %. Individuals with PD performed the experiment in their ON and OFF state. PD demonstrated significantly greater judgement error during BASELINE and FAST conditions compared to HC, although PD did not improve their judgement error during the SLOW condition. Additionally, PD had greater variable error during baseline compared to HC; however, during the SLOW conditions, PD had significantly less variable error compared to baseline and similar variable error to HC participants. Overall, dopaminergic medication did not significantly influence judgement error. Therefore, these results suggest that corrupt processing of sensory information is the main contributor to sensory-perceptual deficits during movement in PD rather than delayed updating of sensory feedback.

  20. Self-estimation of physical ability in stepping over an obstacle is not mediated by visual height perception: a comparison between young and older adults.

    Science.gov (United States)

    Sakurai, Ryota; Fujiwara, Yoshinori; Ishihara, Masami; Yasunaga, Masashi; Ogawa, Susumu; Suzuki, Hiroyuki; Imanaka, Kuniyasu

    2017-07-01

    Older adults tend to overestimate their step-over ability. However, it is unclear as to whether this is caused by inaccurate self-estimation of physical ability or inaccurate perception of height. We, therefore, measured both visual height perception ability and self-estimation of step-over ability among young and older adults. Forty-seven older and 16 young adults performed a height perception test (HPT) and a step-over test (SOT). Participants visually judged the height of vertical bars from distances of 7 and 1 m away in the HPT, then self-estimated and, subsequently, actually performed a step-over action in the SOT. The results showed no significant difference between young and older adults in visual height perception. In the SOT, young adults tended to underestimate their step-over ability, whereas older adults either overestimated their abilities or underestimated them to a lesser extent than did the young adults. Moreover, visual height perception was not correlated with the self-estimation of step-over ability in both young and older adults. These results suggest that the self-overestimation of step-over ability which appeared in some healthy older adults may not be caused by the nature of visual height perception, but by other factor(s), such as the likely age-related nature of self-estimation of physical ability, per se.

  1. 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.)

  2. Estimated capacity of object files in visual short-term memory is not improved by retrieval cueing.

    Science.gov (United States)

    Saiki, Jun; Miyatsuji, Hirofumi

    2009-03-23

    Visual short-term memory (VSTM) has been claimed to maintain three to five feature-bound object representations. Some results showing smaller capacity estimates for feature binding memory have been interpreted as the effects of interference in memory retrieval. However, change-detection tasks may not properly evaluate complex feature-bound representations such as triple conjunctions in VSTM. To understand the general type of feature-bound object representation, evaluation of triple conjunctions is critical. To test whether interference occurs in memory retrieval for complete object file representations in a VSTM task, we cued retrieval in novel paradigms that directly evaluate the memory for triple conjunctions, in comparison with a simple change-detection task. In our multiple object permanence tracking displays, observers monitored for a switch in feature combination between objects during an occlusion period, and we found that a retrieval cue provided no benefit with the triple conjunction tasks, but significant facilitation with the change-detection task, suggesting that low capacity estimates of object file memory in VSTM reflect a limit on maintenance, not retrieval.

  3. 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

  4. A Simple Method for Estimating the Economic Cost of Productivity Loss Due to Blindness and Moderate to Severe Visual Impairment.

    Science.gov (United States)

    Eckert, Kristen A; Carter, Marissa J; Lansingh, Van C; Wilson, David A; Furtado, João M; Frick, Kevin D; Resnikoff, Serge

    2015-01-01

    To estimate the annual loss of productivity from blindness and moderate to severe visual impairment (MSVI) using simple models (analogous to how a rapid assessment model relates to a comprehensive model) based on minimum wage (MW) and gross national income (GNI) per capita (US$, 2011). Cost of blindness (COB) was calculated for the age group ≥50 years in nine sample countries by assuming the loss of current MW and loss of GNI per capita. It was assumed that all individuals work until 65 years old and that half of visual impairment prevalent in the ≥50 years age group is prevalent in the 50-64 years age group. For cost of MSVI (COMSVI), individual wage and GNI loss of 30% was assumed. Results were compared with the values of the uncorrected refractive error (URE) model of productivity loss. COB (MW method) ranged from $0.1 billion in Honduras to $2.5 billion in the United States, and COMSVI ranged from $0.1 billion in Honduras to $5.3 billion in the US. COB (GNI method) ranged from $0.1 million in Honduras to $7.8 billion in the US, and COMSVI ranged from $0.1 billion in Honduras to $16.5 billion in the US. Most GNI method values were near equivalent to those of the URE model. Although most people with blindness and MSVI live in developing countries, the highest productivity losses are in high income countries. The global economy could improve if eye care were made more accessible and more affordable to all.

  5. Detection of malignant right coronary artery anomaly by multi-slice CT coronary angiography

    NARCIS (Netherlands)

    Dirksen, M. S.; Bax, J. J.; Blom, N. A.; Schalij, M. J.; Jukema, W. J.; Vliegen, H. W.; van der Wall, E. E.; de Roos, A.; Lamb, H. J.

    2002-01-01

    Coronary artery anomalies occur in 0.3-0.8% of the population and infer a high risk for sudden cardiac death in young adults. Diagnosis is usually established during coronary angiography, which is hampered by poor spatial visualization. Magnetic resonance imaging is an alternative, but it is not

  6. Preoperative imaging for DIEA perforator flaps: a comparative study of computed tomographic angiography and Doppler ultrasound.

    Science.gov (United States)

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

    2008-01-01

    Abdominal donor-site flaps, including the transverse rectus abdominis musculocutaneous (TRAM) and deep inferior epigastric artery (DIEA) perforator flaps, are standard in autologous breast reconstruction. With significant variation in the vascular anatomy of the abdominal wall, preoperative imaging is essential for preoperative planning and reducing intraoperative error. Doppler and color duplex sonography have been used with varying results, and the quest continues for optimal preoperative assessment. Computed tomographic angiography has recently been proposed as a noninvasive modality for this purpose. This is the first study to formally compare preoperative Doppler ultrasound with computed tomographic angiography for imaging the DIEA. Eight consecutive patients undergoing DIEA perforator flap surgery for breast reconstruction underwent both computed tomographic angiography and Doppler ultrasound preoperatively. All investigations and procedures were performed at the same institution with the same primary and assisting surgeons and the same radiology team. Computed tomographic angiography was superior to Doppler ultrasound at identifying the course of the DIEA and its branching pattern, and in visualizing its perforators. Preoperative computed tomographic angiography was highly specific (100 percent) and more sensitive in mapping and visualizing perforators (p = 0.0078). It was also proficient at identifying the superficial epigastric arterial system and for effectively displaying the results intraoperatively. It was substantially quicker and removed the interobserver error associated with Doppler ultrasonography. The study was ceased after eight patients because of the overwhelming benefit of computed tomographic angiography over Doppler ultrasonography. Computed tomographic angiography is a valuable imaging modality for the preoperative assessment of the donor-site vascular supply for TRAM and DIEA perforator flaps.

  7. 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.

  8. Magnetic resonance angiography: Physical principles and clinical applications

    International Nuclear Information System (INIS)

    Hausmann, R.; Mueller, E.

    1992-01-01

    Within the last four years magnetic resonance angiography (MRA) developed very rapidly towards a well accepted screening technique for vascular examinations as a fast add-on to conventional MR. This review describes the basic physical principles as well as the different methods like time-of-flight and phase-sensitive MRA for visualization of blood vessels. Different applications of 3D, 2D sequential and 3D multivolume MRA are shown from various regions of the head and body. A short outlock to quantitative flow measurments is given in the last chapter including some interesting applications of these techniques which show the still expanding potential of magnetic resonance. (orig.) [de

  9. Achievable Rate Estimation of IEEE 802.11ad Visual Big-Data Uplink Access in Cloud-Enabled Surveillance Applications.

    Science.gov (United States)

    Kim, Joongheon; Kim, Jong-Kook

    2016-01-01

    This paper addresses the computation procedures for estimating the impact of interference in 60 GHz IEEE 802.11ad uplink access in order to construct visual big-data database from randomly deployed surveillance camera sensing devices. The acquired large-scale massive visual information from surveillance camera devices will be used for organizing big-data database, i.e., this estimation is essential for constructing centralized cloud-enabled surveillance database. This performance estimation study captures interference impacts on the target cloud access points from multiple interference components generated by the 60 GHz wireless transmissions from nearby surveillance camera devices to their associated cloud access points. With this uplink interference scenario, the interference impacts on the main wireless transmission from a target surveillance camera device to its associated target cloud access point with a number of settings are measured and estimated under the consideration of 60 GHz radiation characteristics and antenna radiation pattern models.

  10. Achievable Rate Estimation of IEEE 802.11ad Visual Big-Data Uplink Access in Cloud-Enabled Surveillance Applications.

    Directory of Open Access Journals (Sweden)

    Joongheon Kim

    Full Text Available This paper addresses the computation procedures for estimating the impact of interference in 60 GHz IEEE 802.11ad uplink access in order to construct visual big-data database from randomly deployed surveillance camera sensing devices. The acquired large-scale massive visual information from surveillance camera devices will be used for organizing big-data database, i.e., this estimation is essential for constructing centralized cloud-enabled surveillance database. This performance estimation study captures interference impacts on the target cloud access points from multiple interference components generated by the 60 GHz wireless transmissions from nearby surveillance camera devices to their associated cloud access points. With this uplink interference scenario, the interference impacts on the main wireless transmission from a target surveillance camera device to its associated target cloud access point with a number of settings are measured and estimated under the consideration of 60 GHz radiation characteristics and antenna radiation pattern models.

  11. 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

  12. 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.

  13. Image quality in coronary computed tomography angiography

    DEFF Research Database (Denmark)

    Precht, Helle; Gerke, Oke; Thygesen, Jesper

    2018-01-01

    Background Computed tomography (CT) technology is rapidly evolving and software solution developed to optimize image quality and/or lower radiation dose. Purpose To investigate the influence of adaptive statistical iterative reconstruction (ASIR) at different radiation doses in coronary CT...... angiography (CCTA) in detailed image quality. Material and Methods A total of 160 CCTA were reconstructed as follows: 55 scans with filtered back projection (FBP) (650 mA), 51 scans (455 mA) with 30% ASIR (ASIR30), and 54 scans (295 mA) with 60% ASIR (ASIR60). For each reconstruction, subjective image quality...... was assessed by five independent certified cardiologists using a visual grading analysis (VGA) with five predefined image quality criteria consisting of a 5-point scale. Objective measures were contrast, noise, and contrast-to-noise ratio (CNR). Results The CTDIvol resulted in 10.3 mGy, 7.4 mGy, and 4.6 m...

  14. 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)

  15. 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. ...

  16. The visualization and analysis of urban facility pois using network kernel density estimation constrained by multi-factors

    Directory of Open Access Journals (Sweden)

    Wenhao Yu

    Full Text Available The urban facility, one of the most important service providers is usually represented by sets of points in GIS applications using POI (Point of Interest model associated with certain human social activities. The knowledge about distribution intensity and pattern of facility POIs is of great significance in spatial analysis, including urban planning, business location choosing and social recommendations. Kernel Density Estimation (KDE, an efficient spatial statistics tool for facilitating the processes above, plays an important role in spatial density evaluation, because KDE method considers the decay impact of services and allows the enrichment of the information from a very simple input scatter plot to a smooth output density surface. However, the traditional KDE is mainly based on the Euclidean distance, ignoring the fact that in urban street network the service function of POI is carried out over a network-constrained structure, rather than in a Euclidean continuous space. Aiming at this question, this study proposes a computational method of KDE on a network and adopts a new visualization method by using 3-D "wall" surface. Some real conditional factors are also taken into account in this study, such as traffic capacity, road direction and facility difference. In practical works the proposed method is implemented in real POI data in Shenzhen city, China to depict the distribution characteristic of services under impacts of multi-factors.

  17. 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.

  18. Detection of malignant right coronary artery anomaly by multi-slice CT coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Dirksen, M.S.; Roos, A. de; Lamb, H.J. [Department of Radiology, C2-S, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden (Netherlands); Bax, J.J.; Schalij, M.J.; Jukema, W.J.; Vliegen, H.W.; Wall, E.E. van der [Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden (Netherlands); Blom, N.A. [Department of Pediatrics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden (Netherlands)

    2002-07-01

    Coronary artery anomalies occur in 0.3-0.8% of the population and infer a high risk for sudden cardiac death in young adults. Diagnosis is usually established during coronary angiography, which is hampered by poor spatial visualization. Magnetic resonance imaging is an alternative, but it is not feasible in the presence of metal objects or claustrophobia. In this report, a 15-year-old boy experienced ventricular fibrillation and was successfully resuscitated. Cardiac catheterization was inconclusive, and pacemaker implantation prohibited the use of MR imaging. Multi-slice CT coronary angiography revealed a malignant anomalous right coronary artery. (orig.)

  19. The juvenile face as a suitable age indicator in child pornography cases: a pilot study on the reliability of automated and visual estimation approaches.

    Science.gov (United States)

    Ratnayake, M; Obertová, Z; Dose, M; Gabriel, P; Bröker, H M; Brauckmann, M; Barkus, A; Rizgeliene, R; Tutkuviene, J; Ritz-Timme, S; Marasciuolo, L; Gibelli, D; Cattaneo, C

    2014-09-01

    In cases of suspected child pornography, the age of the victim represents a crucial factor for legal prosecution. The conventional methods for age estimation provide unreliable age estimates, particularly if teenage victims are concerned. In this pilot study, the potential of age estimation for screening purposes is explored for juvenile faces. In addition to a visual approach, an automated procedure is introduced, which has the ability to rapidly scan through large numbers of suspicious image data in order to trace juvenile faces. Age estimations were performed by experts, non-experts and the Demonstrator of a developed software on frontal facial images of 50 females aged 10-19 years from Germany, Italy, and Lithuania. To test the accuracy, the mean absolute error (MAE) between the estimates and the real ages was calculated for each examiner and the Demonstrator. The Demonstrator achieved the lowest MAE (1.47 years) for the 50 test images. Decreased image quality had no significant impact on the performance and classification results. The experts delivered slightly less accurate MAE (1.63 years). Throughout the tested age range, both the manual and the automated approach led to reliable age estimates within the limits of natural biological variability. The visual analysis of the face produces reasonably accurate age estimates up to the age of 18 years, which is the legally relevant age threshold for victims in cases of pedo-pornography. This approach can be applied in conjunction with the conventional methods for a preliminary age estimation of juveniles depicted on images.

  20. Qual o erro da angiografia na definição de isquemia miocárdica durante intervenções coronarianas percutâneas? What is the angiography error when defining myocardial ischemia during percutaneous coronary interventions?

    Directory of Open Access Journals (Sweden)

    Fernando Mendes Sant'Anna

    2008-09-01

    Full Text Available FUNDAMENTO: A angiografia vem sendo utilizada como padrão de referência para definição de doença arterial coronariana (DAC, embora suas limitações sejam conhecidas. O valor da medida do fluxo fracionado de reserva do miocárdio (FFR na avaliação da DAC está bem estabelecido. OBJETIVO: O objetivo deste estudo é avaliar a acurácia da angiografia em definir as lesões isquêmicas e sua correlação com o FFR. MÉTODOS: Duzentos e cinqüenta pacientes foram incluídos no estudo (471 vasos. Todas as estenoses > 50% pela estimativa visual da angiografia (EVA foram avaliadas medindo-se o FFR. Se o FFR 0,75 a lesão não foi tratada. As lesões foram divididas em moderadas (BACKGROUND: The angiography has been used as a reference standard to define coronary artery disease (CAD, although its limitations are well-known. The significance of the myocardial fractional flow reserve (FFR in the assessment of CAD is well established. OBJECTIVE: The aim of this study was to evaluate the accuracy of angiography when defining ischemic lesions and its correlation with FFR. METHODS: Two hundred and fifty consecutive patients (471 arteries were included in this study. All stenoses > 50% at the angiography visual estimate (AVE were assessed by FFR measurements. When FFR was 0.75, no interventional treatment was carried out. Offline quantitative coronary angiography (QCA was performed in all stenoses, which were divided in intermediate (< 70% - 327 and severe (125. The correlation coefficients between the diameter of the stenosis (%DS and FFR and the accuracy of VA of the angiography when assessing ischemia were determined. RESULTS: FFR could be obtained in 452 lesions (96%. Mean %DS and FFR were 56 ± 8% and 0.74 and 76 ± 6% and 0.48 for moderate and severe stenoses, respectively. Concordance between QCA and FFR was poor, especially in intermediate stenoses (Spearman's rho = - 0.33, p<0.0001. Visual assessment resulted in an accuracy of 57% and 96% in

  1. Visual information and expert’s idea in Hurst index estimation of the fractional Brownian motion using a diffusion type approximation

    Science.gov (United States)

    Taheriyoun, Ali R.; Moghimbeygi, Meisam

    2017-02-01

    An approximation of the fractional Brownian motion based on the Ornstein-Uhlenbeck process is used to obtain an asymptotic likelihood function. Two estimators of the Hurst index are then presented in the likelihood approach. The first estimator is produced according to the observed values of the sample path; while the second one employs the likelihood function of the incremental process. We also employ visual roughness of realization to restrict the parameter space and to obtain prior information in Bayesian approach. The methods are then compared with three contemporary estimators and an experimental data set is studied.

  2. Effects of cane length and diameter and judgment type on the constant error ratio for estimated height in blindfolded, visually impaired, and sighted participants.

    Science.gov (United States)

    Huang, Kuo-Chen; Leung, Cherng-Yee; Wang, Hsiu-Feng

    2010-04-01

    The purpose of this study was to assess the ability of blindfolded, visually impaired, and sighted individuals to estimate object height as a function of cane length, cane diameter, and judgment type. 48 undergraduate students (ages 20 to 23 years) were recruited to participate in the study. Participants were divided into low-vision, severely myopic, and normal-vision groups. Five stimulus heights were explored with three cane lengths, varying cane diameters, and judgment types. The participants were asked to estimate the stimulus height with or without reference to a standard block. Results showed that the constant error ratio for estimated height improved with decreasing cane length and comparative judgment. The findings were unclear regarding the effect of cane length on haptic perception of height. Implications were discussed for designing environments, such as stair heights, chairs, the magnitude of apertures, etc., for visually impaired individuals.

  3. Endovascular therapy by CO2 angiography to prevent contrast-induced nephropathy in patients with chronic kidney disease: a prospective multicenter trial of CO2 angiography registry.

    Science.gov (United States)

    Fujihara, Masahiko; Kawasaki, Daizo; Shintani, Yoshiaki; Fukunaga, Masashi; Nakama, Tatsuya; Koshida, Ryouji; Higashimori, Akihiro; Yokoi, Yoshiaki

    2015-04-01

    To assess the safety and efficacy of carbon dioxide (CO2) angiography-guided endovascular therapy (EVT) for renal, iliofemoral artery disease. Patients with peripheral vascular disease (PVD) often have chronic kidney disease (CKD) and the use of iodinated contrast media may enhance the risk of contrast-induced nephropathy (CIN). Contrast volume reduction is an effective CIN preventive strategy. A prospective multicenter registry was developed and six clinical centers participated in the study. Patients with an estimated glomerular filtration rate (eGFR) of CO2 angiography-guided EVT was performed; incomplete CO2 angiograms were supplemented by intravascular ultrasound, pressure wire, and/or minimal iodinated contrast media. The primary endpoint was a composite of freedom from renal events and freedom from major CO2 angiography related complications. This study included 98 patients with 109 lesions. The mean eGFR baseline was 35.2±12.7 ml min(-1). CO2 angiography-guided angioplasty were performed in 16 renal arteries, 31 aortoiliac arteries, and 62 superficial femoral arteries. The technical success rate was 97.9%. Average CO2 consumption was 281.4±155.8 ml, average dose of iodinated contrast media was 15.0±18.1 ml. Primary endpoint was 92.8% (91/98). Incidence of CIN was 5.1% (5/98) and CO2 angiography-related complications occurred in 17.3% (17/98). Two cases (2%) developed severe, fatal, nonocclusive mesenteric ischemia (NOMI). This trial showed that CO2 angiography-guided angioplasty was effective for preventing CIN, however, CO2 angiography related complication was somewhat high. © 2014 Wiley Periodicals, Inc.

  4. Influence of adaptive statistical iterative reconstruction algorithm on image quality in coronary computed tomography angiography.

    Science.gov (United States)

    Precht, Helle; Thygesen, Jesper; Gerke, Oke; Egstrup, Kenneth; Waaler, Dag; Lambrechtsen, Jess

    2016-12-01

    Coronary computed tomography angiography (CCTA) requires high spatial and temporal resolution, increased low contrast resolution for the assessment of coronary artery stenosis, plaque detection, and/or non-coronary pathology. Therefore, new reconstruction algorithms, particularly iterative reconstruction (IR) techniques, have been developed in an attempt to improve image quality with no cost in radiation exposure. To evaluate whether adaptive statistical iterative reconstruction (ASIR) enhances perceived image quality in CCTA compared to filtered back projection (FBP). Thirty patients underwent CCTA due to suspected coronary artery disease. Images were reconstructed using FBP, 30% ASIR, and 60% ASIR. Ninety image sets were evaluated by five observers using the subjective visual grading analysis (VGA) and assessed by proportional odds modeling. Objective quality assessment (contrast, noise, and the contrast-to-noise ratio [CNR]) was analyzed with linear mixed effects modeling on log-transformed data. The need for ethical approval was waived by the local ethics committee as the study only involved anonymously collected clinical data. VGA showed significant improvements in sharpness by comparing FBP with ASIR, resulting in odds ratios of 1.54 for 30% ASIR and 1.89 for 60% ASIR ( P  = 0.004). The objective measures showed significant differences between FBP and 60% ASIR ( P  < 0.0001) for noise, with an estimated ratio of 0.82, and for CNR, with an estimated ratio of 1.26. ASIR improved the subjective image quality of parameter sharpness and, objectively, reduced noise and increased CNR.

  5. Dynamic contrast-enhanced subtraction MR angiography in intracranial vascular abnormalities

    International Nuclear Information System (INIS)

    Takano, K.; Ono, H.; Utsunomiya, H.; Okazaki, M.; Tanaka, A.

    1999-01-01

    We present our clinical experience with dynamic contrast-enhanced MR angiography (MRA) with subtraction for assessing intracranial vascular abnormalities. Ten patients with various cerebrovascular disorders underwent dynamic contrast-enhanced MRA on a 1.0-T system. Thirty sections (2 mm) were acquired in 29-30 s. Maximum intensity projection images and subtracted source images were compared with those obtained by conventional angiography. In all cases, the presence or absence of abnormalities in the targeted vessels, as well as the morphology of the sagittal sinuses, was clearly visualized as in conventional angiography, without any obstructions such as hyperintense hematomas or thrombi, or intraluminal turbulence. Although the temporal and spatial resolutions with current hardware are insufficient, these preliminary results suggest that dynamic contrast-enhanced MRA with subtraction may be useful for assessing vascular lesions with hemorrhage or thrombus, and the dural sinuses. (orig.)

  6. Differences in the validity of a visual estimation method for determining patients' meal intake between various meal types and supplied food items.

    Science.gov (United States)

    Kawasaki, Yui; Akamatsu, Rie; Tamaura, Yuki; Sakai, Masashi; Fujiwara, Keiko; Tsutsuura, Satomi

    2018-02-12

    The aim of this study was to examine differences in the validity of a visual estimation method for determining patients' meal intake between various meal types and supplied food items in hospitals and to find factors influencing the validity of a visual estimation method. There are two procedures by which we obtained the information on dietary intake of the patients in these hospitals. These are both by visual assessment from the meal trays at the time of their clearing, by the attending nursing staff and by weighing conducted by researchers. The following criteria are set for the target trays: A) standard or therapeutic meals, which are monitored by a doctor, for energy and/or protein and/or sodium; B) regular, bite-sized, minced and pureed meal texture, and C) half-portion meals. Visual assessment results were tested for their validity by comparing with the corresponding results of weighing. Differences between these two methods indicated the estimated and absolute values of nutrient intake. A total of 255 (76.1%) trays were included in the analysis out of the 335 possible trays and the results indicated that the energy consumption estimates by visual or weighing procedures are not significantly different (412 ± 173 kcal, p = 0.15). However, the mean protein consumption was significantly different (16.3 ± 6.7 g/tray, p types and textures, except for meals with added supplied food items. Nursing staff need to be attentive to supplied food items. Copyright © 2018 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  7. 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

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

    International Nuclear Information System (INIS)

    Chen Shuang; Zhu Ruijiang; Feng Xiaoyuan

    2006-01-01

    Objective: To evaluate the value of Multi-slice spiral CT angiography for spinal cord vessels. Methods: 11 adult subjects with suspected of myelopathy were performed with Multi-slice spiral CT angiography, An iodine contrast agent was injected at 3.5 ml/s, for total 100 ml. The parameters were axial 16 slice mode, 0.625 mm slice thickness, 0.8 s rotation, delay time depending on smartprep(15-25 s), multi-phase scan. The coronal and sagittal MPR and SSD were generated on a workstation compared with spinal digital subtraction angiography (DSA) to analyze normal or abnormal spinal cord vessels. Results: Normal findings at spinal CTA and digital subtraction angiography in six adult normal subjects and spinal cord vascular malformations (1 intradural extramedullary AVF, 4 dural AVFs) in five cases, Recognizable intradural vessels corresponding to anterior median (midline) veins and/or anterior spinal arteries were show in six adult normal subjects. Abnormal intradural vessels were detected in all five spinal cord vascular malformation with CT angiography, in comparison with digital subtraction angiography these vessels were primarily enlarged veins of the coronal venous plexus on the cord surface, radiculomedullary-dural arteries could not be clearly shown in four dural AVF, only one anterior spinal artery was detected in one patient with intradural medullary AVF, which direct shunt between anterior spinal artery and perimedullary vein with tortuous draining vessel. Conclusion: Multi-slice CT angiography is able to visualize the normal or abnormal spinal cord vessels. It could be used as a noninvasive method to screen the spinal cord vascular disease. (authors)

  10. 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.

  11. 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

  12. 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 ...

  13. 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 ...

  14. 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.

  15. 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 ...

  16. 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 ...

  17. 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.

  18. Fluorescein angiography of the canine retina

    International Nuclear Information System (INIS)

    Schaepdrijver, L. de; Simoens, P.; Lauwers, H.

    1996-01-01

    The retinal vascular bed was examined in 37 canine eyes by studying 50 retinal fluorangiograms. All angiographic phases could distinctly be visualized by the use of a small intravenous bolus of 10 mg/kg fluorescein. The choroidal phase is characterized by spot-like and lobular filling of the choriocapillaris. By coalescence of the choroidal lobules, this uneven filling progressively disappears in the subsequent phases. The retinal arterial phase is characterized by a hyperfluorescence of the retinal arterioles at the level of the optic disc border. The time interval between the start of the choroidal phase and the retinal arterial phase is very short due to the common origin of the choroidal and retinal arteries from the choroidoretinal arteries. The retinal arterio-venous phase is characterized by a complete filling of the smaller arterioles, capillaries, and venules. During this phase the branching pattern of the retinal blood vessels at the area centralis region can be most easily studied. This also applies to the periarteriolar capillary-free zones and the radial peripapillary capillaries. The retinal early venous phase is characterized by the onset of laminar flow in the larger retinal venules. A homogeneous and complete filling of the larger venules is characteristic for the onset of the late venous phase. During the retinal venous phase the border venule can be observed just posterior to the ora ciliaris retinae. Fluorescein angiography of the canine retinal microvasculature shows that the dog is less suitable as an experimental animal model in ophthalmology, due to the presence of the choroidal tapetum which reflects fluorescent light and thus diminishes the contrast between the retinal blood vessels and the background

  19. The evaluation of three-dimensional dynamic contrast enhanced MR angiography in portal hypertension

    International Nuclear Information System (INIS)

    Wu Zhuo; Liang Biling; Liu Qingyu; Zhong Jinglian; Ye Ruixin; Ling Yunbiao; Ou Qingjia

    2006-01-01

    Objective: To evaluate the techniques of three-dimensional dynamic contrast enhanced MR angiography (3D DCE MRA)with normative timing of sequences, enhancive 3D slab thickness and subtraction in portosystemic collaterals. Methods: Before April 2003, 12 patients were performed with 75-90 mm of 3D slab thickness and 3-5 repeated sequences estimated by breath, after April 2003, 18 patients were performed with 150-180 mm of 3D slab thickness and 5 normative repeated sequences respectively at 0, 20, 40, 60 and 90 s. After subtracting selective arterial phase images from subsequent portal venous phase images, two radiologists assessed visualization of portal collaterals independently with a four - point scale for ranking of image quality in maximum intensity projection (MIP) images with and without subtraction. Results: Average scores for image quality in visualization of the portal vein with subtraction were significantly depressed compared with the scores without subtraction (2.53±0.49 versus 2.74±0.31, P<0.05). However, subtraction three dimension-maximum intensity projection (3D-MIP) gave superior visualization of portal collaterals compared with non-subtraction 3D-MIP(2.58±0.30 versus 1.63±0.50). A statistically significant difference (P<0.01) was found between the two groups of esophageal varices. Most of portosystemic shunts demonstrated in the same time as the portal vein at about 20s, but some of collaterals demonstrated in delay time. Conclusion: Subtraction 3D-MIP demonstrates portosystemic collaterals more clearly than non-subtraction; normative timing of sequences ensure against omitting varices displayed late, 3 D slab thickness provides details about paraumbilical vein and retroperitoneal collaterals. (authors)

  20. Study on Estimating and Decreasing of Visual Stress Level Caused by the Use of Computers in the Economic Field

    OpenAIRE

    Petru Balogh; Pompiliu Golea; Valentin Inceu

    2013-01-01

    The intensive use of computers in office work and its associated stressors, generate mental and physical demands regarding personnel engaged in this activity. This paper aims to assess the most significant psycho-physiological effects induced in a computer company and to identify direct and indirect symptoms of visual stress, perceived by staff working in the video terminals. Also very important are the organizational measures for the diminishing of visual stress that must be implemented by t...

  1. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-15

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

  3. 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.)

  4. Influence of vessel stenosis on indocyanine green fluorescence intensity assessed by near-infrared fluorescence angiography.

    Science.gov (United States)

    Yamamoto, Masaki; Nishimori, Hideaki; Fukutomi, Takashi; Handa, Takemi; Kihara, Kazuki; Tashiro, Miwa; Sato, Takayuki; Orihashi, Kazumasa

    2017-07-01

    Although useful for visualizing blood flow during revascularization surgery, the permeability of near-infrared fluorescence (NIR) angiography using indocyanine green (ICG) does not allow for vessel stenosis visualization. We hypothesized that changes in ICG fluorescence intensity reflect vessel stenosis, and evaluated the influence of stenosis on blood flow by ex vivo experimentation. The vessel stenosis model comprised a silicon tube, a graft occluder, and artificial blood. During near-infrared angiography, the fluorescense intensity was calculated during pre- and post-stenosis of an artificial circuit, using a NIR angiography. We measured the maximum fluorescence intensity and the time to maximum fluorescence intensity. Severe stenosis (≥75%) attenuated the increase in ICG fluorescence intensity in the tube significantly, pre- and post-stenosis. The time to maximum fluorescence intensity did not differ between sites pre- and post-stenosis, irrespective of stenosis severity. Stenosis affected the ICG fluorescence intensity through the vessel. Thus, quantitative analysis using NIR angiography may detect severe vessel stenosis (≥75%), and the extinction curve of indocyanine fluorescence intensity may support the evaluation of blood flow. The absence of differences in the time to maximum fluorescence intensity for degrees of stenosis might suggest a limitation of previous conventional qualitative assessments.

  5. Parametric color coding of digital subtraction angiography in the evaluation of carotid cavernous fistulas.

    Science.gov (United States)

    Gölitz, P; Struffert, T; Lücking, H; Rösch, J; Knossalla, F; Ganslandt, O; Deuerling-Zheng, Y; Doerfler, A

    2013-06-01

    Angiographic assessment of carotid cavernous fistulas (CCFs) can be complex. Our purpose was to examine whether the use of parametric color coding in the postprocessing of DSA series is advantageous in the evaluation of CCFs. We enrolled 16 patients with angiographically proven CCFs. Endovascular treatment was performed in 14 cases. For postprocessing of digital subtraction angiography (DSA) series, a newly implemented algorithm of parametric color coding was used, turning sequential images of two-dimensional (2D)-DSA series into a single color-coded image. Angiographic data of initial, interventional, and postinterventional 2D-DSA series were compared with color-coded images. Whether parametric color coding could facilitate evaluation of fistula architecture and provide a more precise estimation of fistula venous drainage patterns as well as whether flow analysis could reveal objective changes during and after treatment were investigated. In 56 % of the cases, parametric color coding was observed to facilitate visualization of fistula angioarchitecture. Estimation of fistula drainage flow patterns was considered to be improved in 31 % of the cases. For assessment of hemodynamic changes during and after treatment, parametric color coding was assumed to be helpful in 21 % of the cases, especially because revealing flow changes that were not visible on 2D-DSA series were now visible. Parametric color coding is a fast application tool that might provide additional support in the angiographic evaluation of CCFs. Visualization of complex fistula architecture could be facilitated, and flow analysis might improve assessment of venous drainage patterns, thereby increasing overall diagnostic confidence. During and after treatment, hemodynamic changes that were not visible on 2D-DSA series could now be depicted.

  6. 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

  7. 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

  8. User manual of Visual Balan V. 1.0 Interactive code for water balances and refueling estimation

    International Nuclear Information System (INIS)

    Samper, J.; Huguet, L.; Ares, J.; Garcia, M. A.

    1999-01-01

    This document contains the Users Manual of Visual Balan V1.0, an updated version of Visual Balan V0.0 (Samper et al., 1997). Visual Balan V1.0 performs daily water balances in the soil, the unsaturated zone and the aquifer in a user-friendly environment which facilitates both the input data process and the postprocessing of results. The main inputs of the balance are rainfall and irrigation while the outputs are surface runoff, evapotranspiration, interception, inter flow and groundwater flow. The code evaluates all these components in a sequential manner by starting with rainfall and irrigation, which must be provided by the user, and continuing with interception, surface runoff, evapotranspiration, and potential recharge (water flux crossing the bottom of the soil). This potential recharge is the input to the unsaturated zone where water can flow horizontally as subsurface flow (inter flow) or vertically as percolation into the aquifer. (Author)

  9. Effect of hot bag application on the extremities in angiography of patients with Raynaud's syndrome

    International Nuclear Information System (INIS)

    Won, Je Hwan; Han, Kyong Lim; Kim, Chan

    2004-01-01

    It is sometimes difficult to evaluate the angiographic findings pertaining to spasm of the arteries in the hands and feet in patients with Raynaud's syndrome. The purpose of this study is to investigate the effectiveness of applying a hot bag to the hands and/or feet for the control of vasospasm in patients with Raynaud's syndrome during angiography. Forty five cases (hands: feet=15:30) in forty patients (M:F=9:31, mean age; 39 years) with Raynaud's syndrome whose conventional angiography demonstrated the presence of vasospasm were included. First, digital subtraction angiography of the extremities was performed at room temperature (20 to 21 degrees Celsius). Then a hot bag was applied for 5 minutes on the hand or foot, and a post-hot bag angiography of the extremity was performed. The angiographic findings were classified into 6 grades in the case of the feet (0; anterior/posterior tibial artery, 1; dorsalis pedis /lateral plantar artery, 2; arcuate artery/plantar arch, 3; metatarsal artery, 4; digital artery, 5; blushing of toe tip) and 5 grades in the case of the hands (0; ulnar/radial artery, 1; palmar arch, 2; common palmar artery, 3; proper palmar artery, 4; blushing of finger tip) according to the level of the visualized vessels on the angiography. The time and the time difference to maximal visualization of the vessels between the measurements taken at room temperature and those taken after the hot bag application were calculated. In all cases, more. vessels were visualized after the hot bag application than at room temperature. After the application of the hot bag, the grade of vessel visualization was increased in both the feet (range; 1-4, mean; 2.3) and hands (range; 1-2, mean; 1.4). The time to the maximal visualization of the vessels was faster after the hot bag application than at room temperature. The time difference between the two groups ranged from 1 to 33 seconds (mean; 12.3 seconds) in the feet and 2 to 26 seconds (mean; 11.8 seconds) in the

  10. Machine-smoking studies of cigarette filter color to estimate tar yield by visual assessment and through the use of a colorimeter.

    Science.gov (United States)

    Morton, Michael J; Williams, David L; Hjorth, Heather B; Smith, Jennifer H

    2010-04-01

    This paper explores using the intensity of the stain on the end of the filter ("filter color") as a vehicle for estimating cigarette tar yield, both by instrument reading of the filter color and by visual comparison to a template. The correlation of machine-measured tar yield to filter color measured with a colorimeter was reasonably strong and was relatively unaffected by different puff volumes or different tobacco moistures. However, the correlation of filter color to machine-measured nicotine yield was affected by the moisture content of the cigarette. Filter color, as measured by a colorimeter, was generally comparable to filter extraction of either nicotine or solanesol in its correlation to machine-smoked tar yields. It was found that the color of the tar stain changes over time. Panelists could generally correctly order the filters from machine-smoked cigarettes by tar yield using the intensity of the tar stain. However, there was considerable variation in the panelist-to-panelist tar yield estimates. The wide person-to-person variation in tar yield estimates, and other factors discussed in the text could severely limit the usefulness and practicality of this approach for visually estimating the tar yield of machine-smoked cigarettes. Copyright 2009 Elsevier Inc. All rights reserved.

  11. MR respiratory navigator echo gated coronary angiography at 3 T

    International Nuclear Information System (INIS)

    Chang Shixin; Wang Yibin; Zong Genlin; Hao Nanxin; Du Yushan

    2007-01-01

    Objective: To investigate the techniques and influence factors for the respiratory navigator echo triggered whole-heart coronary MR angiography (WH-CMRA) and evaluate its application in visualizing coronary arteries and the image quality. Methods: Ninety two volunteers were acquired with WH-CMRA at 3 T MR scanner using respiratory navigator-echo gated TFE sequence. Imaging quality was visually graded as 0-IV grade according to the visual inspection, average length, diameter and sharpness of coronary arteries. The correlation between the imaging quality and respiratory pattern, heart rate and navigator efficiency was analyzed. Results: The imaging quality in 92 cases was that 28 were graded as IV, 53 were graded as III, 9 were graded as II and 2 were graded as I. The successful rate of scan was 88% (81/92). The imaging quality is mainly graded as IV when the heart rate was less than 75 beats per minute (bpm) and the sharpness of vessel was (48±11)%. When heart rate was more than 75 bpm, the image quality was mostly graded as 111 and the sharpness was (33±15)%. The correlation between heart rate and imaging quality score was negative (r= -0.726, P O.05). Conclusion: 3 T WH-CMRA technique could facilitated the visualization of whole coronary arteries at free breathing but having indications on heart rate. (authors)

  12. 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.)

  13. En-face optical coherence tomography angiography of neovascularization elsewhere in hemicentral retinal vein occlusion

    Directory of Open Access Journals (Sweden)

    Sogawa K

    2015-10-01

    Full Text Available Kenji Sogawa, Taiji Nagaoka, Akihiro Ishibazawa, Atsushi Takahashi, Tomofumi Tani, Akitoshi Yoshida Department of Ophthalmology, Asahikawa Medical University, Asahikawa, Japan Purpose: To evaluate how the growth of neovascularization elsewhere (NVE was delineated in an eye with hemicentral retinal vein occlusion (CRVO using optical coherence tomography (OCT angiography. Patients and methods: We examined a 64-year-old man diagnosed with hemi-CRVO. The area around the occluded vein was scanned using a spectral-domain OCT device (RTVue XR Avanti. Blood flow was detected using the split-spectrum amplitude-decorrelation angiography (SSADA algorithm. Color fundus photography, fluorescein angiography (FA, and OCT angiography examinations were performed at the first visit and at 3 and 6 months postpresentation. Results: At the first visit, FA revealed delayed retinal venous filling and extensive areas of capillary nonperfusion. The patient underwent a trial of intravitreal ranibizumab injection (0.5 mg/0.05 mL for the treatment of macular edema. At 3 months postpresentation, there was no NVE around the occluded vein in the en-face SSADA image, but at 6 months, NVE appeared on the occluded veins. The en-face SSADA image showed the NVE structure in the fibrovascular membrane on the occluded vein more clearly than FA images. Conclusion: OCT angiography clearly visualized the sprouting of NVE in an eye with hemi-CRVO. New findings of the vascular structure of NVE in hemi-CRVO were revealed using the en-face SSADA algorithm. Keywords: OCT angiography, hemi-CRVO, NVE

  14. Surgical interventions with fatal outcome: utility of multi-phase postmortem CT angiography.

    Science.gov (United States)

    Zerlauth, J-B; Doenz, F; Dominguez, A; Palmiere, C; Uské, A; Meuli, R; Grabherr, S

    2013-02-10

    Cases of fatal outcome after surgical intervention are autopsied to determine the cause of death and to investigate whether medical error caused or contributed to the death. For medico-legal purposes, it is imperative that autopsy findings are documented clearly. Modern imaging techniques such as multi-detector computed tomography (MDCT) and postmortem CT angiography, which is used for vascular system imaging, are useful tools for determining cause of death. The aim of this study was to determine the utility of postmortem CT angiography for the medico-legal death investigation. This study investigated 10 medico-legal cases with a fatal outcome after surgical intervention using multi-phase postmortem whole body CT angiography. A native CT scan was performed as well as three angiographic phases (arterial, venous, and dynamic) using a Virtangio(®) perfusion device and the oily contrast agent, Angiofil(®). The results of conventional autopsy were compared to those from the radiological investigations. We also investigated whether the radiological findings affected the final interpretation of cause-of-death. Causes of death were hemorrhagic shock, intracerebral hemorrhage, septic shock, and a combination of hemorrhage and blood aspiration. The diagnoses were made by conventional autopsy as well as by postmortem CT angiography. Hemorrhage played an important role in eight of ten cases. The radiological exam revealed the exact source of bleeding in seven of the eight cases, whereas conventional autopsy localized the source of bleeding only generally in five of the seven cases. In one case, neither conventional autopsy nor CT angiography identified the source of hemorrhage. We conclude that postmortem CT angiography is extremely useful for investigating deaths following surgical interventions. This technique helps document autopsy findings and allows a second examination if it is needed; specifically, it detects and visualizes the sources of hemorrhages in detail, which

  15. 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

  16. Post-mortem computed tomography angiography utilizing barium sulfate to identify microvascular structures : a preliminary phantom model and case study

    NARCIS (Netherlands)

    Haakma, Wieke; Rohde, Marianne; Kuster, Lidy; Uhrenholt, Lars; Pedersen, Michael; Boel, Lene Warner Thorup

    2016-01-01

    We investigated the use of computer tomography angiography (CTA) to visualize microvascular structures in a vessel-mimicking phantom and post-mortem (PM) bodies. A contrast agent was used based on 22% barium sulfate, 20% polyethylene glycol and 58% distilled water. A vessel-mimicking phantom

  17. 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

  18. Pioneers in angiography: The Portuguese School of Angiography, Second edition

    International Nuclear Information System (INIS)

    Veiga-Pires, J.A.; Grainger, R.G.

    1987-01-01

    Master physician and researcher Egas Moniz and his innovative surgical colleague Reynaldo dos Santoz developed and established the Portugese School, which introduced the science of visualization of the arteries, veins, and lymphatics throughout the body. This second edition of the book on the Portuguese School benefits from the addition of several important documents by these two men, as well as by the inclusion of their brilliant and moving last lectures

  19. Egas Moniz: 90 Years (1927-2017) from Cerebral Angiography.

    Science.gov (United States)

    Artico, Marco; Spoletini, Marialuisa; Fumagalli, Lorenzo; Biagioni, Francesca; Ryskalin, Larisa; Fornai, Francesco; Salvati, Maurizio; Frati, Alessandro; Pastore, Francesco Saverio; Taurone, Samanta

    2017-01-01

    In June 2017 we celebrate the 90th anniversary of the pioneer discovery of cerebral angiography, the seminal imaging technique used for visualizing cerebral blood vessels and vascular alterations as well as other intracranial disorders. Egas Moniz (1874-1955) was the first to describe the use of this revolutionary technique which, until 1975 (when computed tomography, CT, scan was introduced in the clinical practice), was the sole diagnostic tool to provide an imaging of cerebral vessels and therefore alterations due to intracranial pathology. Moniz introduced in the clinical practice this fundamental and important diagnostic tool. The present contribution wishes to pay a tribute to the Portuguese neurosurgeon, who was also a distinguished neurologist and statesman. Despite his tremendous contribution in modern brain imaging, Egas Moniz was awarded the Nobel Prize in Physiology or Medicine in 1949 for prefrontal leucotomy, the neurosurgical intervention nowadays unacceptable, but should rather be remembered for his key contribution to modern brain imaging.

  20. Egas Moniz: 90 Years (1927–2017) from Cerebral Angiography

    Science.gov (United States)

    Artico, Marco; Spoletini, Marialuisa; Fumagalli, Lorenzo; Biagioni, Francesca; Ryskalin, Larisa; Fornai, Francesco; Salvati, Maurizio; Frati, Alessandro; Pastore, Francesco Saverio; Taurone, Samanta

    2017-01-01

    In June 2017 we celebrate the 90th anniversary of the pioneer discovery of cerebral angiography, the seminal imaging technique used for visualizing cerebral blood vessels and vascular alterations as well as other intracranial disorders. Egas Moniz (1874–1955) was the first to describe the use of this revolutionary technique which, until 1975 (when computed tomography, CT, scan was introduced in the clinical practice), was the sole diagnostic tool to provide an imaging of cerebral vessels and therefore alterations due to intracranial pathology. Moniz introduced in the clinical practice this fundamental and important diagnostic tool. The present contribution wishes to pay a tribute to the Portuguese neurosurgeon, who was also a distinguished neurologist and statesman. Despite his tremendous contribution in modern brain imaging, Egas Moniz was awarded the Nobel Prize in Physiology or Medicine in 1949 for prefrontal leucotomy, the neurosurgical intervention nowadays unacceptable, but should rather be remembered for his key contribution to modern brain imaging. PMID:28974927

  1. OCT angiography and visible-light OCT in diabetic retinopathy.

    Science.gov (United States)

    Nesper, Peter L; Soetikno, Brian T; Zhang, Hao F; Fawzi, Amani A

    2017-10-01

    In recent years, advances in optical coherence tomography (OCT) techniques have increased our understanding of diabetic retinopathy, an important microvascular complication of diabetes. OCT angiography is a non-invasive method that visualizes the retinal vasculature by detecting motion contrast from flowing blood. Visible-light OCT shows promise as a novel technique for quantifying retinal hypoxia by measuring the retinal oxygen delivery and metabolic rates. In this article, we discuss recent insights provided by these techniques into the vascular pathophysiology of diabetic retinopathy. The next milestones for these modalities are large multicenter studies to establish consensus on the most reliable and consistent outcome parameters to study diabetic retinopathy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  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. Advanced techniques for digital angiography of the heart

    International Nuclear Information System (INIS)

    Hoehne, K.H.; Obermoeller, U.; Riemer, M.; Witte, G.

    1987-01-01

    Digital angiography is widely considered as being simply a method in which images taken at different times are subtracted from each other. This paper presents some techniques which are performed in the frequency domain after the application of the Fourier Transform. Nonselective bypass angiograms and intravenous ventriculograms are taken as examples to show that simple procedures utilizing these techniques exhibit the advantages of improved signal to noise ratio in the subtraction images, reduction of motion artefacts, easy application of phase-synchronous subtraction, integration and quantitative visualization of blood propagation. Furthermore it is shown that the storage of the angiographic image sequence as Fourier-coefficients leads to data compression and convenient data access in an image database. (Auth.)

  4. Egas Moniz: 90 Years (1927–2017 from Cerebral Angiography

    Directory of Open Access Journals (Sweden)

    Marco Artico

    2017-09-01

    Full Text Available In June 2017 we celebrate the 90th anniversary of the pioneer discovery of cerebral angiography, the seminal imaging technique used for visualizing cerebral blood vessels and vascular alterations as well as other intracranial disorders. Egas Moniz (1874–1955 was the first to describe the use of this revolutionary technique which, until 1975 (when computed tomography, CT, scan was introduced in the clinical practice, was the sole diagnostic tool to provide an imaging of cerebral vessels and therefore alterations due to intracranial pathology. Moniz introduced in the clinical practice this fundamental and important diagnostic tool. The present contribution wishes to pay a tribute to the Portuguese neurosurgeon, who was also a distinguished neurologist and statesman. Despite his tremendous contribution in modern brain imaging, Egas Moniz was awarded the Nobel Prize in Physiology or Medicine in 1949 for prefrontal leucotomy, the neurosurgical intervention nowadays unacceptable, but should rather be remembered for his key contribution to modern brain imaging.

  5. Coronary CT Angiography in the Quantitative Assessment of Coronary Plaques

    Directory of Open Access Journals (Sweden)

    Zhonghua Sun

    2014-01-01

    Full Text Available Coronary computed tomography angiography (CCTA has been recently evaluated for its ability to assess coronary plaque characteristics, including plaque composition. Identification of the relationship between plaque composition by CCTA and patient clinical presentations may provide insight into the pathophysiology of coronary artery plaque, thus assisting identification of vulnerable plaques which are associated with the development of acute coronary syndrome. CCTA-generated 3D visualizations allow evaluation of both coronary lesions and lumen changes, which are considered to enhance the diagnostic performance of CCTA. The purpose of this review is to discuss the recent developments that have occurred in the field of CCTA with regard to its diagnostic accuracy in the quantitative assessment of coronary plaques, with a focus on the characterization of plaque components and identification of vulnerable plaques.

  6. Utility estimation of the application of auditory-visual-tactile sense feedback in respiratory gated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jung Hun; KIm, Byeong Jin; Roh, Shi Won; Lee, Hyeon Chan; Jang, Hyeong Jun; Kim, Hoi Nam [Dept. of Radiation Oncology, Biomedical Engineering, Seoul St. Mary' s Hospital, Seoul (Korea, Republic of); Song, Jae Hoon [Dept. of Biomedical Engineering, Seoul St. Mary' s Hospital, Seoul (Korea, Republic of); Kim, Young Jae [Dept. of Radiological Technology, Gwang Yang Health Collage, Gwangyang (Korea, Republic of)

    2013-03-15

    The purpose of this study was to evaluate the possibility to optimize the gated treatment delivery time and maintenance of stable respiratory by the introduction of breath with the assistance of auditory-visual-tactile sense. The experimenter's respiration were measured by ANZAI 4D system. We obtained natural breathing signal, monitor-induced breathing signal, monitor and ventilator-induced breathing signal, and breath-hold signal using real time monitor during 10 minutes beam-on-time. In order to check the stability of respiratory signals distributed in each group were compared with means, standard deviation, variation value, beam{sub t}ime of the respiratory signal. The stability of each respiratory was measured in consideration of deviation change studied in each respiratory time lapse. As a result of an analysis of respiratory signal, all experimenters has showed that breathing signal used both Real time monitor and Ventilator was the most stable and shortest time. In this study, it was evaluated that respiratory gated radiation therapy with auditory-visual-tactual sense and without auditory-visual-tactual sense feedback. The study showed that respiratory gated radiation therapy delivery time could significantly be improved by the application of video feedback when this is combined with audio-tactual sense assistance. This delivery technique did prove its feasibility to limit the tumor motion during treatment delivery for all patients to a defined value while maintaining the accuracy and proved the applicability of the technique in a conventional clinical schedule.

  7. Utility estimation of the application of auditory-visual-tactile sense feedback in respiratory gated radiation therapy

    International Nuclear Information System (INIS)

    Jo, Jung Hun; KIm, Byeong Jin; Roh, Shi Won; Lee, Hyeon Chan; Jang, Hyeong Jun; Kim, Hoi Nam; Song, Jae Hoon; Kim, Young Jae

    2013-01-01

    The purpose of this study was to evaluate the possibility to optimize the gated treatment delivery time and maintenance of stable respiratory by the introduction of breath with the assistance of auditory-visual-tactile sense. The experimenter's respiration were measured by ANZAI 4D system. We obtained natural breathing signal, monitor-induced breathing signal, monitor and ventilator-induced breathing signal, and breath-hold signal using real time monitor during 10 minutes beam-on-time. In order to check the stability of respiratory signals distributed in each group were compared with means, standard deviation, variation value, beam t ime of the respiratory signal. The stability of each respiratory was measured in consideration of deviation change studied in each respiratory time lapse. As a result of an analysis of respiratory signal, all experimenters has showed that breathing signal used both Real time monitor and Ventilator was the most stable and shortest time. In this study, it was evaluated that respiratory gated radiation therapy with auditory-visual-tactual sense and without auditory-visual-tactual sense feedback. The study showed that respiratory gated radiation therapy delivery time could significantly be improved by the application of video feedback when this is combined with audio-tactual sense assistance. This delivery technique did prove its feasibility to limit the tumor motion during treatment delivery for all patients to a defined value while maintaining the accuracy and proved the applicability of the technique in a conventional clinical schedule

  8. Visualization of Flow in Pressurizer Spray Line Piping and Estimation of Thermal Stress Fluctuation Caused by Swaying of Water Surface

    Science.gov (United States)

    Oumaya, Toru; Nakamura, Akira; Onojima, Daisuke; Takenaka, Nobuyuki

    The pressurizer spray line of PWR plants cools reactor coolant by injecting water into pressurizer. Since the continuous spray flow rate during commercial operation of the plant is considered insufficient to fill the pipe completely, there is a concern that a water surface exists in the pipe and may periodically sway. In order to identify the flow regimes in spray line piping and assess their impact on pipe structure, a flow visualization experiment was conducted. In the experiment, air was used substituted for steam to simulate the gas phase of the pressurizer, and the flow instability causing swaying without condensation was investigated. With a full-scale mock-up made of acrylic, flow under room temperature and atmospheric pressure conditions was visualized, and possible flow regimes were identified based on the results of the experiment. Three representative patterns of swaying of water surface were assumed, and the range of thermal stress fluctuation, when the surface swayed instantaneously, was calculated. With the three patterns of swaying assumed based on the visualization experiment, it was confirmed that the thermal stress amplitude would not exceed the fatigue endurance limit prescribed in the Japanese Design and Construction Code.

  9. 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)

  10. Estimating the relative weights of visual and auditory tau versus heuristic-based cues for time-to-contact judgments in realistic, familiar scenes by older and younger adults.

    Science.gov (United States)

    Keshavarz, Behrang; Campos, Jennifer L; DeLucia, Patricia R; Oberfeld, Daniel

    2017-04-01

    Estimating time to contact (TTC) involves multiple sensory systems, including vision and audition. Previous findings suggested that the ratio of an object's instantaneous optical size/sound intensity to its instantaneous rate of change in optical size/sound intensity (τ) drives TTC judgments. Other evidence has shown that heuristic-based cues are used, including final optical size or final sound pressure level. Most previous studies have used decontextualized and unfamiliar stimuli (e.g., geometric shapes on a blank background). Here we evaluated TTC estimates by using a traffic scene with an approaching vehicle to evaluate the weights of visual and auditory TTC cues under more realistic conditions. Younger (18-39 years) and older (65+ years) participants made TTC estimates in three sensory conditions: visual-only, auditory-only, and audio-visual. Stimuli were presented within an immersive virtual-reality environment, and cue weights were calculated for both visual cues (e.g., visual τ, final optical size) and auditory cues (e.g., auditory τ, final sound pressure level). The results demonstrated the use of visual τ as well as heuristic cues in the visual-only condition. TTC estimates in the auditory-only condition, however, were primarily based on an auditory heuristic cue (final sound pressure level), rather than on auditory τ. In the audio-visual condition, the visual cues dominated overall, with the highest weight being assigned to visual τ by younger adults, and a more equal weighting of visual τ and heuristic cues in older adults. Overall, better characterizing the effects of combined sensory inputs, stimulus characteristics, and age on the cues used to estimate TTC will provide important insights into how these factors may affect everyday behavior.

  11. Effects of Estimators on Ultrasound Nakagami Imaging in Visualizing the Change in the Backscattered Statistics from a Rayleigh Distribution to a Pre-Rayleigh Distribution.

    Science.gov (United States)

    Tsui, Po-Hsiang; Wan, Yung-Liang; Tai, Dar-In; Shu, Yu-Chen

    2015-08-01

    Ultrasound Nakagami imaging has recently attracted interest as an imaging technique for analyzing envelope statistics. Because the presence of structures has a strong effect on estimation of the Nakagami parameter, previous studies have indicated that Nakagami imaging should be used specifically for characterization of soft tissues with fewer structures, such as liver tissues. Typically, changes in the properties of the liver parenchyma cause the backscattered statistics to transform from a Rayleigh distribution to a pre-Rayleigh distribution, and this transformation can be visualized using a Nakagami imaging technique. However, different estimators result in different estimated values; thus, the performance of a Nakagami image may depend on the type of estimator used. This study explored the effects of various estimators on ultrasound Nakagami imaging to describe the backscattered statistics as they change from a Rayleigh distribution to a pre-Rayleigh distribution. Simulations and clinical measurements involving patients with liver fibrosis (n = 85) yielded image data that were used to construct B-mode and conventional Nakagami images based on the moment estimator (denoted as mINV images) and maximum-likelihood estimator (denoted as mML images). In addition, novel window-modulated compounding Nakagami images based on the moment estimator (denoted as mWMC images) were also obtained. The means and standard deviations of the Nakagami parameters were examined as a function of the backscattered statistics. The experimental results indicate that the mINV, mML and mWMC images enabled quantitative visualization of the change in backscattered statistics from a Rayleigh distribution to a pre-Rayleigh distribution. Importantly, the mWMC image is superior to both mINV and mML images because it simultaneously realizes sensitive detection of the backscattered statistics and a reduction of estimation variance for image smoothness improvement. We therefore recommend using m

  12. Spatial Estimation and Visualization of CO2 Emissions for Campus Sustainability: The Case of King Abdullah University of Science and Technology (KAUST, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Yusuf A. Adenle

    2017-11-01

    Full Text Available A total of 21 metric tons of CO2 per person in terms of per capita emissions from consumption of energy was recorded in Saudi Arabia in 2011 and forecasts have shown that this emission of CO2 is increasing. This poses the threat of climate change and global warming and therefore the need for the sustainability of the country. The Kingdom of Saudi Arabia’s Vision for 2030 addresses environmental sustainability that includes a reduction in CO2 emissions as well as diversified economic growth. Universities have been regarded as institutions with significant responsibilities to resolve the issues of sustainability as well as serve as role model to society by implementing a sustainability plan. This study established a spatial evaluation, estimation, and visualization of the CO2 emissions of King Abdullah University of Science and Technology (KAUST, Saudi Arabia. The data required for this study were collected from the overall coverage of the university campus buildings by transforming raster data from the satellite image to vector data in the form of polygons, and then multiplying the area by the number of floors of the individual building. ArcGIS 10.3® (ESRI, Redlands, CA, USA software was used for this campus CO2 emissions evaluation and visualization. The overall estimate of the CO2 emissions for the university campus was 127.7-tons CO2 equivalent. The lowest emission was 0.02-tons CO2 equivalent while the maximum value was 20.9-tons of CO2 equivalent. By this ArcGIS-based evaluation, it is evident that geographically integrated model for campus estimation and visualization of CO2 emissions provides the information for decision makers to develop viable strategies for achieving a higher standard in overall campus sustainability and addressing the issue of climate change.

  13. 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

  14. 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.

  15. Assessment Of Coronary Arterial Stents By Multislice-CT Angiography

    International Nuclear Information System (INIS)

    Maintz, D.; Fallenberg, E. M.; Heindel, W.; Fischbach, R.; Grude, M.

    2003-01-01

    Purpose: To assess patency and lumen visibility of coronary artery stents by multislice-CT angiography (MSCTA) in comparison with conventional coronary angiography as the standard of reference. Material and Methods: 47 stents of 13 different types were evaluated in 29 patients. MSCTA was performed on a 4-slice scanner with a standard coronary protocol (detector collimation 4 x 1 mm; table feed 1.5 mm/rotation, 400 mAs, 120 kV). Image evaluation was performed by two readers who were blinded to the reports from the catheter angiography. MIP reconstructions were evaluated for image quality on a 4-point scale (1 = poor, 4 = excellent) and stent patency (contrast distal to the stent as an indirect patency sign). Axial images and multiplanar reformations through the stents were used for assessment of stent lumen visibility (measurement of the visible stent lumen diameter) and detection of relevant in-stent stenosis (50%). Results: Image quality was fair to good on average (score 2.64 ± 1.0) and depended on the heart rate (heart rate 45-60: average score 3.2, heart rate 61-70: average score 2.8, heart rate >71: average score 1.4). Thirty-seven stents were correctly classified as patent, 1 was correctly classified as occluded and 9 stents were not assessable due to insufficient image quality because of triggering artifacts. Parts of the stent lumen could be visualized in 30 cases. On average, 20-40% of the stent lumen diameter was visible. Twenty-five stents were correctly classified as having no stenosis, 1 was falsely classified as stenosed, 1 was correctly classified as occluded. In 20 stents lumen visibility was not sufficient for stenosis evaluation. Conclusion: Although the stent lumen may be partly visualized in most stents, a reliable evaluation of in-stent stenoses does not seem practical by 4-slice MSCT. Nevertheless, for stent patency evaluation, MS-CTA might provide valuable clinical information. With submillimeter MSCT (e.g. 16-slice scanners) and more

  16. 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

  17. MR angiography of eddy-current-free MR imaging system with a 3T permanent magnet

    International Nuclear Information System (INIS)

    Nishimura, H.; Watanabe, S.; Takeuchi, H.

    1991-01-01

    This paper reports that, the authors main purpose was to evaluate two-dimensional time flight MR angiography in the visualization of vascular structure by using an eddy-current-free 0.3-T permanent magnet MR imaging system. The authors have developed multisection acquisition technique for two-dimensional time-of-flight MR angiography with the use of velocity-compensated gradient echoes. MR angiograms were obtained with a ray-tracing algorithm of the new modified maximum intensity projection at various viewing angles. These angiograms are displayed on cathode-ray tubes in a high-speed cyclic mode to depict the front-rear relation of vessels for better recognition. With an eddy-current-free permanent magnet system, two-dimensional time-of-flight angiography could clearly depict intracranial vascular structure, cervical vessels, and vessels of the extremities with thin-section (2 or 3 mm) acquisition. A high flip angle (90 degrees) with a short TR enabled better differentiation between blood flow and stationary tissues. Stenosis of the carotids could be detected in accordance with digital subtraction angiography

  18. Optical Coherence Tomography Angiography in Retinal Vascular Diseases and Choroidal Neovascularization

    Directory of Open Access Journals (Sweden)

    Rodolfo Mastropasqua

    2015-01-01

    Full Text Available Purpose. To assess the ability of optical coherence tomography-angiography (OCT-A to show and analyze retinal vascular patterns and the choroidal neovascularization (CNV in retinal vascular diseases. Methods. Seven eyes of seven consecutive patients with retinal vascular diseases were examined. Two healthy subjects served as controls. All eyes were scanned with the SD-OCT XR Avanti (Optovue Inc, Fremont CA, USA. Split spectrum amplitude decorrelation angiography algorithm was used to identify the blood flow within the tissue. Fluorescein angiography (FA and indocyanine green angiography (ICGA with Spectralis HRA + OCT (Heidelberg Engineering GmbH were performed. Results. In healthy subjects OCT-A visualized major macular vessels and detailed capillary networks around the foveal avascular zone. Patients were affected with myopic CNV (2 eyes, age-related macular degeneration related (2, branch retinal vein occlusion (BRVO (2, and branch retinal artery occlusion (BRAO (1. OCT-A images provided distinct vascular patterns, distinguishing perfused and nonperfused areas in BRVO and BRAO and recognizing the presence, location, and size of CNV. Conclusions. OCT-A provides detailed images of retinal vascular plexuses and quantitative data of pathologic structures. Further studies are warranted to define the role of OCT-A in the assessment of retinovascular diseases, with respect to conventional FA and ICG-A.

  19. 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

  20. Non-enhanced MR angiography of renal arteries - Comparison with contrast-enhanced MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Angeretti, M. G.; Lumia, D.; Cani, A.; Barresi, M.; Cardim, L Nocchi; Piacentino, F.; Genovese, E. A.; Fugazzola, C. [Dept. of Radiology, Insubria Univ., Ospedale di Circolo e Fondazione Macchi, Varese (Italy)], e-mail: laranocchi@gmail.com; Maresca, A. M. [Dept. of Internal Medicine, Insubria Univ., Ospedale di Circolo e Fondazione Macchi, Varese (Italy); Novario, R. [Dept. of Medical Physics, Insubria Univ., Ospedale di Circolo e Fondazione Macchi, Varese (Italy)

    2013-09-15

    Background: The main causes of renal artery stenosis (RAS) are atherosclerosis and fibromuscular dysplasia. Despite contrast-enhanced magnetic resonance angiography (CE-MRA) being a safe and reliable method for diagnosis of RAS especially in young individuals, recently it has been possible to adopt innovative technologies that do not require paramagnetic contrast agents. Purpose: To assess the accuracy of steady-state free-precession (SSFP) non-contrast-enhanced magnetic resonance angiography (NC-MRA) by using a 1.5 T MR scanner for the detection of renal artery stenosis, in comparison with breath-hold CE-MRA as the reference standard. Material and Methods: Sixty-three patients (33 men, 30 women) with suspected renovascular hypertension (RVHT) were examined by a 1.5T MR scanner; NC-MRA with an electrocardiography (ECG)-gated SSFP sequence was performed in 58.7% (37/63) of patients; in 41.3% (26/63) of patients a respiratory trigger was used in addition to cardiac gating. CE-MRA, with a three-dimensional gradient echo (3D-GRE) T1-weighted sequence, was performed in all patients within the same session. Maximum intensity projection (MIP) image quality, number of renal arteries, and the presence of stenosis were assessed by two observers (independently for NC-MRA and together for CE-MRA). The agreement between NC-MRA and CE-MRA as well as the inter-observer reproducibility were calculated with Bland-Altman plots. Results: MIP image quality was considered better for NC-MRA. NC-MRA identified 143 of 144 (99.3%) arteries detected by CE-MRA (an accessory artery was not identified). Fourteen stenoses were detected by CE-MRA (11 atherosclerotic, 3 dysplastic) with four of 14 (28.5%) significant stenosis. Bland-Altman plot demonstrated an excellent concordance between NC-MRA and CE-MRA; particularly, the reader A evaluated correctly all investigated arteries, while over-estimation of two stenoses occurred for reader B. Regarding NC-MRA, inter-observer agreement was excellent

  1. 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.

  2. 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.)

  3. 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 ...

  4. 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 ...

  5. 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

  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. 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 ...

  8. 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...

  9. 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

  10. 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.

  11. 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

  12. Influence of adaptive statistical iterative reconstruction algorithm on image quality in coronary computed tomography angiography

    Directory of Open Access Journals (Sweden)

    Helle Precht

    2016-12-01

    Full Text Available Background Coronary computed tomography angiography (CCTA requires high spatial and temporal resolution, increased low contrast resolution for the assessment of coronary artery stenosis, plaque detection, and/or non-coronary pathology. Therefore, new reconstruction algorithms, particularly iterative reconstruction (IR techniques, have been developed in an attempt to improve image quality with no cost in radiation exposure. Purpose To evaluate whether adaptive statistical iterative reconstruction (ASIR enhances perceived image quality in CCTA compared to filtered back projection (FBP. Material and Methods Thirty patients underwent CCTA due to suspected coronary artery disease. Images were reconstructed using FBP, 30% ASIR, and 60% ASIR. Ninety image sets were evaluated by five observers using the subjective visual grading analysis (VGA and assessed by proportional odds modeling. Objective quality assessment (contrast, noise, and the contrast-to-noise ratio [CNR] was analyzed with linear mixed effects modeling on log-transformed data. The need for ethical approval was waived by the local ethics committee as the study only involved anonymously collected clinical data. Results VGA showed significant improvements in sharpness by comparing FBP with ASIR, resulting in odds ratios of 1.54 for 30% ASIR and 1.89 for 60% ASIR (P = 0.004. The objective measures showed significant differences between FBP and 60% ASIR (P < 0.0001 for noise, with an estimated ratio of 0.82, and for CNR, with an estimated ratio of 1.26. Conclusion ASIR improved the subjective image quality of parameter sharpness and, objectively, reduced noise and increased CNR.

  13. OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY REVEALS BLOOD FLOW IN CHOROIDAL NEOVASCULAR MEMBRANE IN REMISSION PHASE OF NEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

    Science.gov (United States)

    Ichiyama, Yusuke; Sawada, Tomoko; Ito, Yuka; Kakinoki, Masashi; Ohji, Masahito

    2017-04-01

    The aim of the study was to investigate blood flow in choroidal neovascular membrane in remission phase of neovascular age-related macular degeneration using optical coherence tomography (OCT) angiography. OCT angiography was obtained in eyes with remission phase of neovascular age-related macular degeneration after treatments, defined as no exudative change (such as macular edema, subretinal fluid, and subretinal hemorrhage) observed in eyes without any treatment for neovascular age-related macular degeneration within the previous 6 months. Irregular blood flows shown in the segmentation of outer retina detected by OCT angiography were considered as blood flows in choroidal neovascular membrane. The vascular area and vessel density were obtained from OCT angiography images. Twenty eyes of 20 patients were included in this analysis. The blood flows in choroidal neovascular membrane were observed in all eyes (100%) using OCT angiography. The mean vascular area was 3.81 ± 3.41 mm and the mean vessel density of lesion was 28.9 ± 8.2%. The vessel density was significantly correlated with best-corrected visual acuity and duration of remission (best-corrected visual acuity: P = 0.008, r = -0.576; duration of remission: P = 0.017, r = -0.525, respectively). Optical coherence tomography angiography revealed that blood flows in choroidal neovascular membrane remained in eyes with clinically inactive neovascular age-related macular degeneration.

  14. Coupled parametric model for estimation of visual field tests based on OCT macular thickness maps, and vice versa, in glaucoma care.

    Science.gov (United States)

    Tsai, Andy; Caprioli, Joseph; Shen, Lucy Q

    2012-01-01

    The current standard of care for glaucoma patients consists of functional assessment of vision via visual field (VF) testing, which is sensitive but subjective, time-consuming, and often unreliable. A new imaging technology, Fourier domain optical coherence tomography (OCT), is being introduced to assess the structural characteristics of the macula. This new complementary exam is efficient, objective, and reliable. A complex, but consistent, relationship exists between the structural information provided by macular OCT and the functional information gathered by VF maps. We propose a learning-based framework with the ability to estimate the VF map based on OCT macular thickness measurements as input (and vice versa). Central to this algorithmic framework is a coupled parametric model that captures not only the individual variabilities of the OCT macular thickness measurements and the VF maps, but also their co-dependencies. This model is derived by applying principal component analysis (PCA) to a library consisting of various pairs of OCT and VF maps. The parameters of this coupled model are obtained by solving a linear least squares problem. Next, these estimated parameters are used, in conjunction with the eigenvectors derived from PCA, to compute the estimate. The accuracy of this coupled parametric estimation model was evaluated by performing multiple leave-one-out cross validation experiments. Copyright © 2011 Elsevier B.V. All rights reserved.

  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. Multi-slice spiral CT coronary angiography: influence of heart rate and reconstruction window on image quality

    International Nuclear Information System (INIS)

    Mao Dingbiao; Hua Yanqing; Wang Mingpeng; Zhang Guozhen; Wu Weilan; Hu Fei; Ge Xiaojun; Ding Qiyong

    2004-01-01

    Objective: To evaluate the influence of heart rate and reconstruction window on image quality of multi-slice spiral CT coronary angiography. Methods: Retrospectively ECG-gated MSCT coronary angiography were performed in 80 healthy cases. Results: Four coronary (RCA, LM, LAD, LCX) segments were analyzed in each patient with regard to image quality. 82.1% (46/56) of the coronary segments were sufficient for analysis in patients with heart rate ≤60 bpm, 63.4% (104/164) with 61-70 bpm, 41.2%(28/68) with 71-80 bpm, and 31.2%(10/32) with>80 bpm, respectively. The left anterior descending artery, left circumflex artery, and the right coronary artery were best visualized when the reconstruction window was 60%-70%, 50%-60%, and 50%-70%, respectively. Conclusion: Image quality of MSCT coronary angiography is highly dependent on heart rate and reconstruction window

  17. 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.

  18. The Usefulness of Three-Dimensional Angiography with a Flat Panel Detector of Direct Conversion Type in a Transcatheter Arterial Chemoembolization Procedure for Hepatocellular Carcinoma: Initial Experience

    International Nuclear Information System (INIS)

    Kakeda, Shingo; Korogi, Yukunori; Hatakeyama, Yoshihisa; Ohnari, Norihiro; Oda, Nobuhiro; Nishino, Kazuyoshi; Miyamoto, Wataru

    2008-01-01

    The purpose of this study was to assess the usefulness of a three-dimensional (3D) angiography system using a flat panel detector of direct conversion type in treatments with subsegmental transcatheter arterial chemoembolization (TACE) for hepatocellular carcinomas (HCCs). Thirty-six consecutive patients who underwent hepatic angiography were prospectively examined. First, two radiologists evaluated the degree of visualization of the peripheral branches of the hepatic arteries on 3D digital subtraction angiography (DSA). Then the radiologists evaluated the visualization of tumor staining and feeding arteries in 25 patients (30 HCCs) who underwent subsegmental TACE. The two radiologists who performed the TACE assessed whether the additional information provided by 3D DSA was useful for treatments. In 34 (94.4%) of 36 patients, the subsegmental branches of the hepatic arteries were sufficiently visualized. The feeding arteries of HCCs were sufficiently visualized in 28 (93%) of 30 HCCs, whereas tumor stains were sufficiently visualized in 18 (60%). Maximum intensity projection images were significantly superior to volume recording images for visualization of the tumor staining and feeding arteries of HCCs. In 27 (90%) of 30 HCCs, 3D DSA provided additional useful information for subsegmental TACE. The high-quality 3D DSA with flat panel detector angiography system provided a precise vascular road map, which was useful for performing subsegmental TACE .of HCCs

  19. [Value of angiography and embolisation in treatment of head and neck vascular malformations at Otolaryngology Department, Poznań University of Medical Sciences, Poland].

    Science.gov (United States)

    Wróbel, Maciej; Kopeć, Tomasz; Juszkat, Robert; Szyfterl, Witold; Borucki, Łukasz

    2008-01-01

    Angiography is an invasive, radiological investigation of vascular system. It plays an important role within variety of diagnostic tools in head and neck pathologies. In selected cases with well defined tumor supply vessels, angiography may be combined with intravascular obliteration. This possibility widen indications, which comprise diagnostic arteriographies - visualization of blood supply and extension of vascularization; therapeutic and diagnostic arteriographies - palliative or radical in character, dependent on pathology; and therapeutic angiographies as adjuvant therapy prior to surgical treatment. Authors present their experience with endovascular techniques application in head and neck pathologies. Material comprised 59 angiographies performed in patients treated at Otolaryngology Department at Poznań University of Medical Sciences between 2000-2007. In conclusion authors emphasize advantages and disadvantages, as well as, the role of the endovascular treatment in head and neck surgery.

  20. Accessory optical device for the Heidelberg retina angiograph ( HRA classic to perform angiography of the vitreous cavity and the anterior eye segment

    Directory of Open Access Journals (Sweden)

    Mennel Stefan

    2007-01-01

    Full Text Available The Heidelberg retina angiograph ( HRA classic enables fluorescein angiography (FA and indocyanine green angiography (ICG-A of the retina and choroid. The goal of this study was to design an accessory device to adapt the HRA classic for application on structures anterior to the retina. The optical device consisted of a cylindrical two-piece plastic frame holding a magnifying lens commonly used with the indirect ophthalmoscope. A 60-diopters lens was inserted in this frame to enable the angiography of the anterior segment. A less strong lens of 30 diopters was used for the visualization of pathologic findings in the vitreous cavity. We designed an easy-to-use and low-cost device to adapt the HRA classic for angiography of the fundus, vitreous cavity and anterior segment in the same session and without delay. FA and ICG-A images of two patients with rubeosis iridis and of one patient with choroidal melanoma are described.

  1. 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

  2. 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

  3. Three-dimensional black blood MR angiography of the liver during breath holding. A comparison with two-dimensional time-of-flight MR angiography

    International Nuclear Information System (INIS)

    Suto, Y.; Ohuchi, Y.; Kimura, T.; Shirakawa, T.; Mizuuchi, N.; Takizawa, O.; Yamane, T.; Kamba, M.; Moriyama, S.; Ohta, Y.

    1994-01-01

    In 2-D time-of-flight MR angiography (2-D TOF MRA) of the liver, artifacts caused by respiratory motion are unavoidable. Therefore, a 3-D black blood MRA of the liver was attempted in 7 healthy volunteers, using a 3-D gradient echo sequence which allows imaging during breath holding. 2-D TOF MRA was performed as well. In all subjects, 3-D MRA allowed visualization of the trunk, 1st-, and 2nd-order branches of the portal vein without interruption. Right 3rd-order branches were visualized without interruption in 6 of 7 subjects (85%). However, with 2-D MRA, the transverse portion of the left main portal vein could not be visualized in any subject, and the periphery of the portal vein was less clear than with 3-D MRA. (orig.)

  4. Diagnostic impact of anterior segment angiography of limbal stem cell insufficiency in PAX6-related aniridia.

    Science.gov (United States)

    Käsmann-Kellner, Barbara; Latta, Lorenz; Fries, Fabian N; Viestenz, Arne; Seitz, Berthold

    2018-04-01

    PAX6 is a master gene of ocular development and postnatal ocular equilibrium. Congenital aniridia is the hallmark of PAX6 gene haploinsufficiency (Chr. 11 p. 13), but PAX6-associated aniridia is a profound, progressive pan-ocular developmental disorder often leading to blindness. There is congenital visual impairment with advancing loss of vision mainly due to secondary glaucoma and to corneal blindness caused by limbal stem cell insufficiency (LSCI). LSCI leads to ARK (aniridia-related keratopathy), which typically develops in four stages. Incipient LSCI with vessels starting to grow into the cornea can be imaged by fluorescein anterior segment angiography, which enables fine vessels to be more easily detected than by routine slit lamp examination, especially in patients with nystagmus. Thus, clinical stage 1 ARK is often diagnosed at stage 2 by angiography. Corneal neovascularizations often start at the 12 and 6 positions and subsequently progress circumferentially, not at the 3 and 9 positions as previously believed. Anterior segment angiography can provide an easily standardizable tool for monitoring progress, treatment-induced regress or stabilization of ARK. Especially in children, angiography could be used to monitor new treatment regimens for reducing LSCI. Angiography could enable treatment to begin earlier to preserve corneal hemostasis. In addition, the fact that vascularization often starts at the subpalpebral 6 and 12 positions as opposed to the 3 and 9 positions raises more questions concerning factors that promote LSCI and related corneal injuries. Clin. Anat. 31:392-397, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  5. Parathyroid gland angiography with indocyanine green fluorescence to predict parathyroid function after thyroid surgery.

    Science.gov (United States)

    Vidal Fortuny, J; Belfontali, V; Sadowski, S M; Karenovics, W; Guigard, S; Triponez, F

    2016-04-01

    Postoperative hypoparathyroidism remains the most common complication following thyroidectomy. The aim of this pilot study was to evaluate the use of intraoperative parathyroid gland angiography in predicting normal parathyroid gland function after thyroid surgery. Angiography with the fluorescent dye indocyanine green (ICG) was performed in patients undergoing total thyroidectomy, to visualize vascularization of identified parathyroid glands. Some 36 patients underwent ICG angiography during thyroidectomy. All patients received standard calcium and vitamin D supplementation. At least one well vascularized parathyroid gland was demonstrated by ICG angiography in 30 patients. All 30 patients had parathyroid hormone (PTH) levels in the normal range on postoperative day (POD) 1 and 10, and only one patient exhibited asymptomatic hypocalcaemia on POD 1. Mean(s.d.) PTH and calcium levels in these patients were 3·3(1·4) pmol/l and 2·27(0·10) mmol/l respectively on POD 1, and 4·0(1.6) pmol/l and 2·32(0·08) mmol/l on POD 10. Two of the six patients in whom no well vascularized parathyroid gland could be demonstrated developed transient hypoparathyroidism. None of the 36 patients presented symptomatic hypocalcaemia, and none received treatment for hypoparathyroidism. PTH levels on POD 1 were normal in all patients who had at least one well vascularized parathyroid gland demonstrated during surgery by ICG angiography, and none required treatment for hypoparathyroidism. © 2016 The Authors. BJS published by John Wiley & Sons Ltd on behalf of BJS Society Ltd.

  6. Improved estimates of percolation and anisotropic permeability from 3-D X-ray microtomography using stochastic analyses and visualization

    Science.gov (United States)

    Liu, Jie; Regenauer-Lieb, Klaus; Hines, Chris; Liu, Keyu; Gaede, Oliver; Squelch, Andrew

    2009-05-01

    X-ray microtomography (micro-CT) with micron resolution enables new ways of characterizing microstructures and opens pathways for forward calculations of multiscale rock properties. A quantitative characterization of the microstructure is the first step in this challenge. We developed a new approach to extract scale-dependent characteristics of porosity, percolation, and anisotropic permeability from 3-D microstructural models of rocks. The Hoshen-Kopelman algorithm of percolation theory is employed for a standard percolation analysis. The anisotropy of permeability is calculated by means of the star volume distribution approach. The local porosity distribution and local percolation probability are obtained by using the local porosity theory. Additionally, the local anisotropy distribution is defined and analyzed through two empirical probability density functions, the isotropy index and the elongation index. For such a high-resolution data set, the typical data sizes of the CT images are on the order of gigabytes to tens of gigabytes; thus an extremely large number of calculations are required. To resolve this large memory problem parallelization in OpenMP was used to optimally harness the shared memory infrastructure on cache coherent Non-Uniform Memory Access architecture machines such as the iVEC SGI Altix 3700Bx2 Supercomputer. We see adequate visualization of the results as an important element in this first pioneering study.

  7. Visual threshold estimation and its relation to the question: Fechner-law or Stevens-power function.

    Science.gov (United States)

    Thoss, F

    1986-01-01

    This investigation was initiated by the apparent rivalry between Fechner-law and Stevens-power function. We used the pupil reaction as on objective measure for the excitation of the visual system within both the threshold and the suprathreshold region. The course of the threshold as a function of adaptation light shows important differences at different field areas. The Weber-law is valid only in the case of large fields (30 degrees) as had been used by Weber himself. At smaller fields the threshold may be described as a power function with exponents of 0.5 at the smallest (0.5 degrees) and about 0.75 at medium sized (5 degrees) fields. In all these experiments the Fechner-hypothesis is suitable automatically because of the constant increment of pupil constriction at the threshold. The validity of the Fechner-hypothesis together with the approximation of the threshold course by power functions lead to Stevens-power functions for the suprathreshold region. The Fechner-law - a logarithmic function - is valid at large fields only. This consideration has been confirmed by our measurements in the suprathreshold sphere.

  8. A New Questionnaire for Estimating the Severity of Visual Height Intolerance and Acrophobia by a Metric Interval Scale

    Directory of Open Access Journals (Sweden)

    Doreen Huppert

    2017-06-01

    Full Text Available AimsTo construct and validate a short scale for the assessment of the severity of visual height intolerance (vHI and acrophobia.MethodsThe questionnaire was developed from two earlier representative epidemiological studies (n = 5,529. Items were applied in a telephone survey of a representative population-based sample.ResultsA total of 1,960 persons were included. The life-time prevalence of vHI was 32.7% (f: 36.1%; m: 28.4%; 12% of these persons fulfilled the psychiatric criteria of acrophobia. Rasch analysis of 11 items on severity, symptoms, and triggers resulted in an 8-item scale with good fit to the model. The score differentiated well between persons with and without acrophobia. The distribution of the scores on the metric scale of the questionnaires of those individuals with acrophobia is separate and distinct from that of susceptibles without acrophobia, although there is some overlap.ConclusionOur proposed short questionnaire (vHISS, see Table 1 and Supplementary Material allows a continuous quantification of the severity of vHI within a metric interval scale from 0 to 13. The diagnosis of acrophobia can be established by including two additional questions.

  9. 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

  10. Evaluation of the portal venous system using MR angiography in patients with severe liver dysfunction

    International Nuclear Information System (INIS)

    Fukatsu, Hiroshi; Ando, Yoko; Yamakawa, Koji; Ishigaki, Takeo

    1994-01-01

    Fifteen patients of chronic liver dysfunction were examined with 2D TOF MR angiography to assess the portal venous system condition. All of the collateral pathways except esophageal varices were clearly demonstrated in all cases, portal vein thromboses were accurately diagnosed in two cases. Portal vein visualization index were determined as follows: good delineation of the main portal vein only; good delineation of the first tributaries of the intrahepatic portal vein; good delineation of the second or further tributaries. This index showed good correlation with the clinical stage proposed by Japan liver cancer study group. These results suggested that MR angiography has a potential for the evaluation of the portal system in patients with severe liver dysfunction. (author)

  11. Diagnosing coronary artery disease after a positive coronary computed tomography angiography

    DEFF Research Database (Denmark)

    Nissen, L; Winther, S; Westra, J

    2018-01-01

    of this study was to determine the diagnostic accuracy of cardiac magnetic resonance (CMR) and myocardial perfusion scintigraphy (MPS) against ICA with fractional flow reserve (FFR) in patients suspected of CAD by CCTA. Methods and results: Included were consecutive patients (1675) referred to CCTA......Aims: Perfusion scans after coronary computed tomography angiography (CCTA) in patients with suspected coronary artery disease (CAD) may reduce unnecessary invasive coronary angiographies (ICAs). However, the diagnostic accuracy of perfusion scans after primary CCTA is unknown. The aim...... with symptoms of CAD and low/intermediate risk profile. Patients with suspected CAD based on CCTA were randomized 1:1 to CMR or MPS followed by ICA with FFR. Obstructive CAD was defined as FFR ≤ 0.80 or > 90% diameter stenosis by visual assessment. After initial CCTA, 392 patients (23%) were randomized; 197...

  12. Value of OCT Angiography in the Diagnosis of Choroidal Neovascularization Complicating Multiple Evanescence White Dot Syndrome.

    Science.gov (United States)

    Nozaki, Miho; Hamada, Satoshi; Kimura, Masayo; Yoshida, Munenori; Ogura, Yuichiro

    2016-06-01

    This report describes a 19-year-old patient with the rare association of multiple evanescent white dot syndrome (MEWDS) and choroidal neovascularization (CNV). Despite the initial diagnosis of MEWDS, her vision significantly decreased. Fluorescein angiography showed dye leakage and pooling at the macula, whereas optical coherence tomography (OCT) showed cystoid macular edema and serous neuroepithelial elevation. The dye leakage and pooling made it impossible to diagnose CNV. However, OCT angiography (OCTA) revealed a vascular structure in the outer retina, thereby leading to the CNV diagnosis. Visual acuity improved after an anti-vascular endothelial growth factor injection. OCTA proved to be useful in the diagnosis of CNV. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:580-584.]. Copyright 2016, SLACK Incorporated.

  13. Assessing body image in anorexia nervosa using biometric self-avatars in virtual reality: Attitudinal components rather than visual body size estimation are distorted.

    Science.gov (United States)

    Mölbert, S C; Thaler, A; Mohler, B J; Streuber, S; Romero, J; Black, M J; Zipfel, S; Karnath, H-O; Giel, K E

    2018-03-01

    Body image disturbance (BID) is a core symptom of anorexia nervosa (AN), but as yet distinctive features of BID are unknown. The present study aimed at disentangling perceptual and attitudinal components of BID in AN. We investigated n = 24 women with AN and n = 24 controls. Based on a three-dimensional (3D) body scan, we created realistic virtual 3D bodies (avatars) for each participant that were varied through a range of ±20% of the participants' weights. Avatars were presented in a virtual reality mirror scenario. Using different psychophysical tasks, participants identified and adjusted their actual and their desired body weight. To test for general perceptual biases in estimating body weight, a second experiment investigated perception of weight and shape matched avatars with another identity. Women with AN and controls underestimated their weight, with a trend that women with AN underestimated more. The average desired body of controls had normal weight while the average desired weight of women with AN corresponded to extreme AN (DSM-5). Correlation analyses revealed that desired body weight, but not accuracy of weight estimation, was associated with eating disorder symptoms. In the second experiment, both groups estimated accurately while the most attractive body was similar to Experiment 1. Our results contradict the widespread assumption that patients with AN overestimate their body weight due to visual distortions. Rather, they illustrate that BID might be driven by distorted attitudes with regard to the desired body. Clinical interventions should aim at helping patients with AN to change their desired weight.

  14. Intraarterial CT Angiography Using Ultra Low Volume of Iodine Contrast – Own Experiences

    International Nuclear Information System (INIS)

    Garcarek, Jerzy; Kurcz, Jacek; Guziński, Maciej; Banasik, Mirosław; Miś, Marcin; Gołębiowski, Tomasz

    2015-01-01

    High volume of intravenous contrast in CT-angiography may result in contrast-induced nephropathy. Intraarterial ultra-low volume of contrast medium results in its satisfactory blood concentration with potentially good image quality. The first main purpose was to assess the influence of the method on function of transplanted kidney in patients with impaired graft function. The second main purpose of the study was to evaluate the usefulness of this method for detection of gastrointestinal and head-and-neck haemorrhages. Between 2010 and 2013 intraarterial CT-angiography was performed in 56 patients, including 28 with chronic kidney disease (CKD). There were three main subgroups: 18 patients after kidney transplantation, 10 patients with gastrointestinal hemorrhage, 8 patients with head-and-neck hemorrhage. Contralateral or ipsilateral inguinal arterial approach was performed. The 4-French vascular sheaths and 4F-catheters were introduced under fluoroscopy. Intraarterial CT was performed using 64-slice scanner. The scanning protocol was as follows: slice thickness 0.625 mm, pitch 1.3, gantry rotation 0.6 sec., scanning delay 1–2 sec. The extent of the study was established on the basis of scout image. In patients with CKD 6–8 mL of Iodixanol (320 mg/mL) diluted with saline to 18–24 mL was administered at a speed of 4–5 mL/s. Vasculature was properly visualized in all patients. In patients with impaired renal function creatinine/eGFR levels remained stable in all but one case. Traditional arteriography failed and CT-angiography demonstrated the site of bleeding in 3 of 10 patients with symptoms of gastrointestinal bleeding (30%). In 8 patients with head-and-neck bleeding CT-angiography did not prove beneficial when compared to traditional arteriography. 1. Ultra-low contrast intraarterial CT-angiography does not deteriorate the function of transplanted kidneys in patients with impaired graft function. 2. 3D reconstructions allow for excellent visualization of

  15. Evaluation and quality control of digital subtraction angiography systems

    International Nuclear Information System (INIS)

    Louisot, P.

    1986-04-01

    After reviewing the development of systems used in angiography, we rewind the medical interest and describe the steps of an angiographic examination. The following chapter is dedicated to the techniques used for the digitalization of video images. The components of the system involved in the image acquisition are thoroughly investigated in chapter 4. Then, we analyse the capabilities of the machines available in France in 1985. Chapter 6 is devoted to the criteria of quality in digital imaging. In order to assign qualitative values to the above criteria, we design a control procedure which is described in chapter 7. The procedure thus allows the estimate of the physical performances of angiographic digital subtraction systems [fr

  16. Rest and exercise radionuclide angiography for diagnosis in chronic ischemic heart disease

    International Nuclear Information System (INIS)

    Gibbons, R.J.

    1991-01-01

    Rest and exercise radionuclide angiography is frequently employed for the diagnosis of chest pain syndromes. Its value and limitations in this regard have been well studied, but proper utilization of the technique requires an understanding of five critical concepts: (1) Radionuclide angiography is superior to treadmill exercise testing and probably equivalent to thallium scintigraphy, although the published series did not use current methods. (2) The true specificity of radionuclide angiography is about 80%, intermediate between the early optimistic estimates and the later pessimistic ones. (3) The peak exercise ejection fraction is the preferred test parameter for diagnosis, although exercise hemodynamics, symptoms, and electrocardiographic changes should also be considered. (4) Although radionuclide angiography is clearly helpful for noninvasive diagnosis, significant numbers of patients will continue to fall in an uncertain category. (5) The proper application of the technique requires recognition of its limitations and careful attention to technical details. When properly applied, this modality can make an important contribution to clinical decision making. 58 references

  17. The value of applying nitroglycerin in 3D coronary MR angiography with real-time navigation technique

    International Nuclear Information System (INIS)

    Hackenbroch, M.; Meyer, C.; Schmiedel, A.; Hofer, U.; Flacke, S.; Kovacs, A.; Schild, H.; Sommer, T.; Tiemann, K.; Skowasch, D.

    2004-01-01

    Purpose: Nitroglycerin administration results in dilation of epicardial coronary vessels and in an increase in coronary blood flow, and has been suggested to improve MR coronary angiography. This study evaluates systematically whether administration of nitroglycerin improves the visualization of coronary arteries and, as a result, the detection of coronary artery stenosis during free breathing 3D coronary MR angiography. Materials and Methods: Coronary MR angiography was performed in 44 patients with suspected coronary artery disease at a 1.5 Tesla System (Intera, Philips Medical Systems) (a) with and (b) without continuous administration of intravenous nitroglycerin at a dose rate of 2.5 mg/h, using an ECG gated gradient echo sequence with real-time navigator correction (turbo field echo, in-plane resolution 0.70 x 0.79 mm 2 , acquisition window 80 ms). Equivalent segments of the coronary arteries in the sequences with and without nitroglycerin were evaluated for visualized vessel length and diameter, qualitative assessment of visualization using a four point grading scale and detection of stenoses >50%. Catheter coronary angiography was used as a gold-standard. Results: No significant differences were found between scans with and without nitroglycerin as to average length of the contiguously visualized vessel length (p>0.05) and diameter (p>0.05). There was also no significant difference in the coronary MR angiography with and without nitroglycerin in the average qualitative assessment score of the visualization of LM, proximal LAD, proximal CX, and proximal and distal RCA (2.1±0.8 and 2.2±0.7; p> 0.05). Sensitivity (77% [17/22] vs. 82% [18/22] p>0.05) and specificity (72% [13/18] vs. 72% [13/18] p>0.05) for the detection of coronary artery stenosis also did not differ significantly between scans with and without intravenous administration of nitroglycerin. Conclusion: Administration of nitroglycerin does not improve visualization of the coronary arteries and

  18. 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

  19. 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

  20. 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.)

  1. 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

  2. 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.

  3. 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.

  4. Inter- and intra-observer agreement of BI-RADS-based subjective visual estimation of amount of fibroglandular breast tissue with magnetic resonance imaging: comparison to automated quantitative assessment

    Energy Technology Data Exchange (ETDEWEB)

    Wengert, G.J.; Helbich, T.H.; Woitek, R.; Kapetas, P.; Clauser, P.; Baltzer, P.A. [Medical University of Vienna/ Vienna General Hospital, Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Vienna (Austria); Vogl, W.D. [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Computational Imaging Research Lab, Wien (Austria); Weber, M. [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Division of General and Pediatric Radiology, Wien (Austria); Meyer-Baese, A. [State University of Florida, Department of Scientific Computing in Medicine, Tallahassee, FL (United States); Pinker, Katja [Medical University of Vienna/ Vienna General Hospital, Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Vienna (Austria); State University of Florida, Department of Scientific Computing in Medicine, Tallahassee, FL (United States); Memorial Sloan-Kettering Cancer Center, Department of Radiology, Molecular Imaging and Therapy Services, New York City, NY (United States)

    2016-11-15

    To evaluate the inter-/intra-observer agreement of BI-RADS-based subjective visual estimation of the amount of fibroglandular tissue (FGT) with magnetic resonance imaging (MRI), and to investigate whether FGT assessment benefits from an automated, observer-independent, quantitative MRI measurement by comparing both approaches. Eighty women with no imaging abnormalities (BI-RADS 1 and 2) were included in this institutional review board (IRB)-approved prospective study. All women underwent un-enhanced breast MRI. Four radiologists independently assessed FGT with MRI by subjective visual estimation according to BI-RADS. Automated observer-independent quantitative measurement of FGT with MRI was performed using a previously described measurement system. Inter-/intra-observer agreements of qualitative and quantitative FGT measurements were assessed using Cohen's kappa (k). Inexperienced readers achieved moderate inter-/intra-observer agreement and experienced readers a substantial inter- and perfect intra-observer agreement for subjective visual estimation of FGT. Practice and experience reduced observer-dependency. Automated observer-independent quantitative measurement of FGT was successfully performed and revealed only fair to moderate agreement (k = 0.209-0.497) with subjective visual estimations of FGT. Subjective visual estimation of FGT with MRI shows moderate intra-/inter-observer agreement, which can be improved by practice and experience. Automated observer-independent quantitative measurements of FGT are necessary to allow a standardized risk evaluation. (orig.)

  5. 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.

  6. A screen for constituents of motor control and decision making in Drosophila reveals visual distance-estimation neurons

    Science.gov (United States)

    Triphan, Tilman; Nern, Aljoscha; Roberts, Sonia F.; Korff, Wyatt; Naiman, Daniel Q.; Strauss, Roland

    2016-01-01

    Climbing over chasms larger than step size is vital to fruit flies, since foraging and mating are achieved while walking. Flies avoid futile climbing attempts by processing parallax-motion vision to estimate gap width. To identify neuronal substrates of climbing control, we screened a large collection of fly lines with temporarily inactivated neuronal populations in a novel high-throughput assay described here. The observed climbing phenotypes were classified; lines in each group are reported. Selected lines were further analysed by high-resolution video cinematography. One striking class of flies attempts to climb chasms of unsurmountable width; expression analysis guided us to C2 optic-lobe interneurons. Inactivation of C2 or the closely related C3 neurons with highly specific intersectional driver lines consistently reproduced hyperactive climbing whereas strong or weak artificial depolarization of C2/C3 neurons strongly or mildly decreased climbing frequency. Contrast-manipulation experiments support our conclusion that C2/C3 neurons are part of the distance-evaluation system. PMID:27255169

  7. Estimation of Pleural Fluid Volumes on Chest Radiography Using Computed Tomography Volumetric Analysis: An Update of the Visual Prediction Rule.

    Science.gov (United States)

    Mammarappallil, Joseph G; Anderson, Sarah A; Danelson, Kerry A; Stitzel, Joel A; Chiles, Caroline

    2015-09-01

    The purpose of the study was to determine the volumes of pleural fluid (PF) required to produce visible menisci in the lateral and posterior costophrenic angles (CPA) and obscure the hemidiaphragms (HD) on upright frontal and lateral chest radiographs (CXRs), using volumetric analysis of chest computed tomography (CT). A total of 98 patients with small pleural effusions on chest CT, in whom CXRs were obtained within a 24-hour interval, were selected for retrospective analysis. PF within each hemithorax was quantified using a semiautomatic method of image segmentation. A cardiothoracic radiologist scored each hemithorax on each CXR from 0 to 3 (0-normal CPA, 1--fluid meniscus below the HD, 2--fluid meniscus at the level of the HD, 3--fluid opacity obscures the HD). Each CXR category was correlated with CT-determined PF volumes. A mean of 20 mL of PF was present on CT without a visible correlate on CXR. A meniscus below the HD on CXR correlated with roughly 100 mL; a meniscus occurring at the HD correlated with roughly 250 mL; a meniscus obscuring the HD correlated with a mean of approximately 650 mL. There were large standard deviations for all PF volumes. We provide guidelines for estimating PF volumes on upright frontal and lateral CXRs. We also confirm that the lateral radiograph is more sensitive for detection of small pleural effusions, with blunting of the posterior CPA only correlating with a mean of 26 mL of PF.

  8. In-vivo studies of new vector velocity and adaptive spectral estimators in medical ultrasound

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Lindskov

    Wave Excitation. Furthermore two different adaptive spectral estimators have been investigated: Blood spectral Power Capon method (BPC) and Blood Amplitude and Phase Estimation method (BAPES). The novel techniques investigated in this thesis are developed to circumvent some of the main limitations...... estimate blood velocities angle independently with a high frame rate. Complex vessel geometries in the cardiovascular system were explored in-vivo on four volunteers using the technique. Flow patterns previously visualized with magnetic resonance angiography and predicted by models of computational fluid...... dynamics, were shown for the first time with ultrasound. Additionally, new information on complex flow patterns in bifurcations and around venous valves was discovered. BPC and BAPES are adaptive spectral estimators which can produce spectrograms with a high temporal resolution. Spectrograms obtained in...

  9. The choroidal circulation assessed by laser-targeted angiography.

    Science.gov (United States)

    Hirata, Yuya; Nishiwaki, Hirokazu

    2006-03-01

    The choroid plays an important role in supplying nutrients to and removing waste products from the outer region of the retina. Abnormal choroidal blood flow can disrupt normal retinal function and lead to alterations in visual function. Visualization of the choriocapillaris in vivo is a great challenge to understanding its normal physiology and involvement in the disease process. Laser-targeted angiography (LTA) is a relatively new method used to visualize and analyze the choroidal circulation. Carboxyfluorescein (CF), encapsulated in heat-sensitive liposomes, is released locally in the choroid through the application of a heat beam provided by an infrared laser. Video angiograms are generated with excitation illumination provided by an argon laser. Obtained images are highly selective to the choriocapillaris and are sharply contrasted against underlying and overlying structures. The images can be obtained repetitively, during which period the circulating liposome concentration is sufficient to generate adequate angiograms. These high-quality images have revealed three distinct phases (filling, plateau, and draining) of the choriocapillaris. In the plateau phase, a cluster of lobules fed by a common arteriole has been uniformly illuminated. This defined cluster area does not change in size while an infrared laser is continuously applied to the same spot, which demonstrates that each cluster is functionally independent and no physiological communication exists between them. Only in posterior regions do the angiograms demonstrate during the filling and draining phases that each lobule is filled from a central spot and drained along a peripheral ring, showing honeycomb flow patterns. The regional differences in choriocapillaris flow patterns revealed by LTA suggests that the choriocapillaris provides a more highly efficient system of outflow in posterior regions than in peripheral regions. LTA is useful in analyzing choroidal circulation in vivo and has the potential

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

    Directory of Open Access Journals (Sweden)

    Francisco Flávio Costa Filho

    2015-11-01

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

  11. Gated tomographic radionuclide angiography using cadmium-zinc-telluride detector gamma camera; comparison to traditional gamma cameras

    DEFF Research Database (Denmark)

    Jensen, Maria Maj; Schmidt, Ulla; Huang, Chenxi

    2014-01-01

    PURPOSE: Estimation of left ventricular ejection fraction (LVEF) with equilibrium 99MTc-HSA equilibrium radionuclide angiography (MUGA) is frequently used for assessing cardiac function. The purpose of this study was to compare intra- and interobserver variation between three different gamma...

  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. Optimized subtraction coronary CT angiography protocol for clinical use with short breath-holding time-initial experience.

    Science.gov (United States)

    Kidoh, Masafumi; Utsunomiya, Daisuke; Oda, Seitaro; Yuki, Hideaki; Funama, Yoshinori; Namimoto, Tomohiro; Yamamuro, Megumi; Yamashita, Yasuyuki

    2015-01-01

    Subtraction coronary computed tomography (CT) angiography (CCTA), which enables the removal of calcium and coronary stents from CCTA images, has been clinically introduced on a second-generation 320-row CT scanner. However, this technique for clinical use is not optimized. The long breath-holding time for two data acquisitions, which causes image misregistration and patient's discomfort, may limit the clinical availability of this subtraction technique. This study received approval from the institutional review board; prior informed consent to participate was obtained from all patients. We performed subtraction CCTA of five patients using the test injection method and optimized the interval time between the first (pulmonary-arterial phase) and the second (coronary-arterial phase) scans to achieve robust subtraction. The patients' breath-holding times were recorded. We compared breath-holding times between our new protocol and previous study's protocol (estimated). Mean breath-holding time in our new protocol was 18.3 ± 3.4 seconds and that in previous protocol was 29.8 ± 3.6 seconds (difference in mean breath-holding time was 11.5 seconds). Misregistration artifacts were not shown in final subtraction CCTA images. These images improved luminal visualization in the calcified lesion. Our test injection protocol can shorten the breath-holding time, which is helpful for successful subtraction CCTA imaging, potentially resulting in an increase of subtraction CCTA examinations in many institutions. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  14. 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.

  15. Flat Panel Angiography in the Cross-Sectional Imaging of the Temporal Bone: Assessment of Image Quality and Radiation Dose Compared with a 64-Section Multisection CT Scanner.

    Science.gov (United States)

    Conte, G; Scola, E; Calloni, S; Brambilla, R; Campoleoni, M; Lombardi, L; Di Berardino, F; Zanetti, D; Gaini, L M; Triulzi, F; Sina, C

    2017-10-01

    Cross-sectional imaging of the temporal bone is challenging because of the complexity and small dimensions of the anatomic structures. We evaluated the role of flat panel angiography in the cross-sectional imaging of the temporal bone by comparing its image quality and radiation dose with a 64-section multisection CT scanner. We retrospectively collected 29 multisection CT and 29 flat panel angiography images of normal whole-head temporal bones. Image quality was assessed by 2 neuroradiologists, who rated the visualization of 30 anatomic structures with a 3-point ordinal scale. The radiation dose was assessed with an anthropomorphic phantom. Flat panel angiography showed better image quality than multisection CT in depicting the anterior and posterior crura of the stapes, the footplate of the stapes, the stapedius muscle, and the anterior ligament of the malleus ( P panel angiography in assessing the tympanic membrane, the bone marrow of the malleus and incus, the tendon of the tensor tympani, the interscalar septum, and the modiolus of the cochlea ( P panel angiography had a significantly higher overall image quality rating than multisection CT ( P = .035). A reduction of the effective dose of approximately 40% was demonstrated for flat panel angiography compared with multisection CT. Flat panel angiography shows strengths and weaknesses compared with multisection CT. It is more susceptible to artifacts, but due to the higher spatial resolution, it shows equal or higher image quality in assessing some bony structures of diagnostic interest. The lower radiation dose is an additional advantage of flat panel angiography. © 2017 by American Journal of Neuroradiology.

  16. Fusion of magnetic resonance angiography and magnetic resonance imaging for surgical planning for meningioma. Technical note

    International Nuclear Information System (INIS)

    Kashimura, Hiroshi; Ogasawara, Kuniaki; Arai, Hiroshi

    2008-01-01

    A fusion technique for magnetic resonance (MR) angiography and MR imaging was developed to help assess the peritumoral angioarchitecture during surgical planning for meningioma. Three-dimensional time-of-flight (3D-TOF) and 3D-spoiled gradient recalled (SPGR) datasets were obtained from 10 patients with intracranial meningioma, and fused using newly developed volume registration and visualization software. Maximum intensity projection (MIP) images from 3D-TOF MR angiography and axial SPGR MR imaging were displayed at the same time on the monitor. Selecting a vessel on the real-time MIP image indicated the corresponding points on the axial image automatically. Fusion images showed displacement of the anterior cerebral or middle cerebral artery in 7 patients and encasement of the anterior cerebral arteries in I patient, with no relationship between the main arterial trunk and tumor in 2 patients. Fusion of MR angiography and MR imaging can clarify relationships between the intracranial vasculature and meningioma, and may be helpful for surgical planning for meningioma. (author)

  17. OCT angiography of acute non-arteritic anterior ischemic optic neuropathy.

    Science.gov (United States)

    Rougier, M-B; Delyfer, M-N; Korobelnik, J-F

    2017-02-01

    To describe changes of the retinal peripapillary microvasculature on optical coherence tomography angiography (OCT-A) in non-arteritic anterior ischemic optic (NAION) neuropathy. Observational study of 10 patients at the acute phase of NAION. OCT-A was performed using a 3mm×3mm square centered on the optic disc (Cirrus HD-OCT with Angioplex, Carl Zeiss Meditec, Dublin, CA). A qualitative comparison was made with the healthy fellow eye of each patient. All patients had a fluorescein angiography (HRA2, Heidelberg, Germany) and a visual field examination (Octopus 101 ® , Haag-Streit, USA). In the affected eyes, OCT-A showed clear modifications in the radial peripapillary network. In all these eyes, a focal disappearance of the superficial capillary radial pattern was present, twisted and irregular. In 8 eyes, there was also a lack of vascularization in some focal areas, appearing as dark areas. No correlation was found between the topography of the vascular alteration shown on OCT-A and visual field pattern defects. OCT-A is a new imaging technology able to demonstrate easily and safely the changes in the peripapillary capillary network during the acute phase of NAION. These changes are likely related to a decrease of the prelaminar optic nerve blood flow during the acute phase of NAION. Visual field defects are not correlated with OCT-A images, suggesting that they may be due mainly to disturbances in posterior ciliary artery blood flow. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  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. 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.

  2. The multidetector computed tomography angiography (MDCTA) in the diagnosis of splenic artery aneurysm and pseudoaneurysm

    Energy Technology Data Exchange (ETDEWEB)

    Saba, Luca; Mallarini, Giorgio (Dept. of Radiology, Azienda Ospedaliero Universitaria (AOU), Cagliari (Italy)), email: lucasaba@tiscali.it; Anzidei, Michele; Lucatelli, Pierleone (Dept. of Radiological Sciences, Univ. of Rome La Sapienza, Rome (Italy))

    2011-06-15

    Splenic artery aneurysm is the most frequent visceral artery aneurysm and rupture of the aneurysm is associated with a high mortality rate. It is important to discriminate between a true aneurysm and a pseudoaneurysm that may be caused by pancreatitis, iatrogenic and postoperative causes, trauma and peptic ulcer disease. Multidetector-row CT angiography (MDCTA) allows detailed visualization of the vascular anatomy and may allow identification of aneurysms and pseudoaneurysms that affect the splenic artery. The objective of this article is to provide a review of the general characteristics of splenic artery aneurysms and pseudoaneurysms and to describe the findings of MDCTA

  3. Swept-Source Optical Coherence Tomography Angiography Findings in Torpedo Maculopathy.

    Science.gov (United States)

    Ali, Zaria; Shields, Carol Lally; Jasani, Kirti; Aslam, Tariq Mehmood; Balaskas, Konstantinos

    2017-11-01

    Torpedo maculopathy is a rare congenital anomaly of the retinal pigment epithelium (RPE). Various imaging modalities have been used to assess cases of torpedo maculopathy, including optical coherence tomography (OCT) and fundus autofluorescence (FAF). OCT angiography (OCTA) offers combined structural and flow characteristics of imaged lesions. The authors present OCTA findings in two cases of torpedo maculopathy. Common features include loss of RPE and choriocapillaris allowing greater visualization of larger vessels in the outer choroid. This confirms the potential of OCTA to provide greater detail of retinal and choroidal architecture and elucidate the histopathology of retino-choridal lesions. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:932-935.]. Copyright 2017, SLACK Incorporated.

  4. Optical coherence tomography angiography features of bilateral retinopathy associated with Chikungunya fever.

    Science.gov (United States)

    Agarwal, Aniruddha; Choudhary, Tripti; Gupta, Vishali

    2018-01-01

    A 66-year-old male patient presented with decreased vision in both eyes following episode of Chikungunya fever. Examination revealed bilateral retinal lesions with stippled pigmentary changes at the level of the choriocapillaris, involving the macula in the left eye. The retinopathy consisted of outer retinal disruption and retinochoroidal flow abnormalities detected using with additional imaging, including spectral-domain optical coherence tomography (OCT), autofluorescence, and OCT angiography (OCTA). The index case report describes unique OCTA findings in both eyes of an elderly male secondary to Chikungunya fever. Using the technique of OCTA, insights into the mechanisms of visual damage in viral retinopathies such as Chikungunya fever can be understood.

  5. 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...

  6. 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...

  7. 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.

  8. 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

  9. Imaging choroidal neovascular membrane using en face swept-source optical coherence tomography angiography

    Directory of Open Access Journals (Sweden)

    Moussa M

    2017-10-01

    Full Text Available Magdy Moussa,1,2 Mahmoud Leila,3 Hagar Khalid1,2 1Ophthalmology Department, Faculty of Medicine, Tanta University, Tanta, Egypt; 2MEDIC Eye Center, Tanta, Egypt; 3Retina Department, Research Institute of Ophthalmology, Giza, Egypt Purpose: The aim of this study was to assess the efficacy of swept-source optical coherence tomography angiography (SS-OCTA in delineating the morphology of choroidal neovascular membrane (CNV. Patients and methods: This was a retrospective observational case series reviewing clinical data and fundus fluorescein angiography (FFA, swept-source optical coherence tomography (SS-OCT, and SS-OCTA images of patients with CNV and comparing the findings. The swept-source technology enables deeper penetration and superior axial resolution. The incorporated blood flow detection algorithm, optical coherence tomography angiography ratio analysis (OCTARA, enables visualization of CNV in vivo without the need for dye injection. Results: The study included 136 eyes of 105 patients. Active lesions on SS-OCTA images showed increased capillary density, extensive arborization, vascular anastomosis and looping, and peri-lesional hollow. Inactive lesions showed decreased capillary density, presence of large linear vessels, and presence of feeder vessels supplying the CNV. We detected positive correlation between SS-OCTA, FFA, and SS-OCT images in 97% of eyes. In the remaining 3%, SS-OCTA confirmed the absence of CNV, whereas FFA and SS-OCT either were inconclusive in the diagnosis of CNV or yielded false-positive results. Conclusion: SS-OCT and SS-OCTA represent a reproducible risk-free analog for FFA in imaging CNV. SS-OCTA is particularly versatile in cases where FFA and SS-OCT are inconclusive. Keywords: swept-source OCT, OCT angiography, imaging of CNV, OCTARA algorithm

  10. Prevalence and Characteristics of Myocardial Bridging in Multidetector-Row Computed Tomography Coronary Angiography

    International Nuclear Information System (INIS)

    Carrascosa, Patricia; Martin Lopez, Elba; Capunay, Carlos; Deviggiano, Alejandro; Vallejos, Javier; Carrascosa, Jorge

    2009-01-01

    Background: Myocardial bridging (MB) are congenital defects of the coronary arteries in which a segment of an epicardial artery lies in the myocardium for part of its course. The current gold standard for diagnosing MB is coronary angiography; however other invasive techniques are also useful. Myocardial bridging can also be visualized with the use of novel non-invasive imaging techniques such as multidetector-row computed tomography coronary angiography (MDCT-CA). Objectives: To assess the prevalence and characteristics of myocardial bridging in patients undergoing multidetector-row computed tomography coronary angiography (MDCT-CA). Material and Methods: A total of 452 consecutive patients were evaluated with 16-row and 64-row MDCT-CA due to the presence of abnormal findings in myocardial perfusion image tests, symptoms suggestive of coronary artery disease, and in asymptomatic patients with a family history of coronary artery disease. The presence of MB, their location and characteristics were analyzed. Myocardial bridging were classified as complete and incomplete bridges with respect to continuity of the myocardium over the tunneled segment of the artery involved. Quantitative measurements of vessel diameter during systole and diastole were evaluated. Results: The prevalence of MB was 35.18%; 88 were complete and 71 incomplete. Among complete MB, 6 affected both systole and diastole, 27 presented only systolic compression and 55 showed no compression. Incomplete MB showed absence of arterial compression. Conclusions: Multidetector-row computed tomography coronary angiography detected a higher prevalence of MB in the study population and allowed to classify them and to assess their functional aspects throughout the cardiac cycle. (authors) [es

  11. 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

  12. Detection of the delayed cerebral vasospams by MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Ueyama, Takehiko; Kuwamura, Keiichi; Saitoh, Minoru; Mandai, Kazuhiro; Takaishi, Yoshiyuki (Hyogo Prefectural Awaji Hospital, Sumoto (Japan))

    1994-05-01

    The usefulness of MR angiography (MRA) for the detection of the cerebral vasospasm after subarachnoid hemorrhage (SAH) was studied. Fourteen out of 69 patients of SAH between Jan 1992 and Dec 1993 underwent both CAG and MRA at the time of pre-spasm, spasm and postspasm period. MRA was performed using an MRT-200FXII(Toshiba Corp., Tokyo. 1.5T). Most images were obtained using the 3D-TOF subtraction method. Cerebral arteries were divided into 4 portions, which consisted of A[sub 1], A[sub 2] and M[sub 1], M[sub 2]. The angiographical findings of both CAG and MRA were studied at each divided area (such as M[sub 1] or M[sub 2]) in the view of the presence or absence of vasospasm. Cerebral vasospasm on CAG and MRA were defined as arteries with a caliber less than 75% and 50% of the original size respectively. The compatibilities between the findings of MRA and CAG were 98% at the territory of ACA and 91% at MCA. The territory of 22% of the arteries was not visualized on MRA due to the artifact caused by aneurysmal clips. However, the total compatibility of MRA and CAG was 94%. The MRA is useful and will become the noninvasive diagnostic tool for the detection of the cerebral vasospasm. (author).

  13. Diagnosis of cardiovascular diseases by digital fluoroscopic angiography

    International Nuclear Information System (INIS)

    Takahashi, Mutsumasa; Hirota, Yoshihisa; Tsuchigame, Naotoshi

    1982-01-01

    Digital fluoroscopic angiography (DFA) is a recently developed angiocardiographic technique, which consists of digitization and real-time subtraction of X-ray transmission data from an image intensifier and television fluoroscopic system. A prototype unit based on this principle was developed and installed at our hospital and initial clinical trial has been performed. Fifty-three examinations were performed on 49 patients with various cardiovascular conditions. DFA was useful in demonstration of intracardiac shunt, and valvular diseases secondary to congenital heart diseases. In ischemic heart diseases, DFA noninvasively demonstrated the heart wall motion, making it possible to evaluate dyskinesis, akinesis and ventricular aneurysm. DFA was also valuable in visualizing disproportionate enlargement of cardiac chambers, stasis, and frequently regurgitation of contrast media in valvular heart diseases. Abnormal mediastinal enlargement and aortic aneurysm were differentiated from other conditions to good advantage. DFA will be used more widely in the above conditions because of non-invasive and simple procedures. Future effort should be directed towards improvement of spatial resolution and development of new algorithm for hemodynamic evaluation. (author)

  14. Prognostic significance of MR angiography in patients with cerebral infarction

    International Nuclear Information System (INIS)

    Moon, Woong Jae; Kim, Jun Ho; Seo, Jeong Jin; Cho, Ki Hyun; Kim, Yun Hyeon; Kim, Jae Kyu; Kang, Heoung Keun

    1994-01-01

    This study was designed to evaluate the prognostic significance of Magnetic resonance angiography(MRA) in patients with cerebral infarction. Magnetic Resonance Imaging(MRI) and 2 dimensional or 3 dimensional Time-of-Flight MRA were performed subsequently in 83 patients with cerebral infarction proven by brain CT and clinical manifestations, using GE Signa Advantage 1.5 T. We classified the size of infarction on MRI as Extent I( 6 cm) and classified the intracranial vascular occlusion according to visualizations of intracranial vascular branches on MRA as Grade 0, Grade I, Grade II, Grade III. And we evaluated clinical outcomes of these patients according to Rankin's disability scale, compared with MRI and MRA. In 72 cases(86.8%), the larger the size of infarction on MRI, the more severe vascular occlusion on MRA, the worse the clinical outcomes were noted(p < 0.01). However, in 7 cases(8.4%) who showed huge cerebral infarction on MRI with low grade intracranial vascular occlusion on MRA, the clinical outcomes were improved. In 4 cases(4.8%) who noted small sized cerebral infarction on MRI with high grade vascular occlusion on MRA, the clinical outcomes were worsened. MRA provides additional useful information to that provided by MRI in predicting the prognosis of patients with cerebral infarction

  15. 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

  16. 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 ...

  17. 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...

  18. Inter- and intra-observer agreement of BI-RADS-based subjective visual estimation of amount of fibroglandular breast tissue with magnetic resonance imaging: comparison to automated quantitative assessment.

    Science.gov (United States)

    Wengert, G J; Helbich, T H; Woitek, R; Kapetas, P; Clauser, P; Baltzer, P A; Vogl, W-D; Weber, M; Meyer-Baese, A; Pinker, Katja

    2016-11-01

    To evaluate the inter-/intra-observer agreement of BI-RADS-based subjective visual estimation of the amount of fibroglandular tissue (FGT) with magnetic resonance imaging (MRI), and to investigate whether FGT assessment benefits from an automated, observer-independent, quantitative MRI measurement by comparing both approaches. Eighty women with no imaging abnormalities (BI-RADS 1 and 2) were included in this institutional review board (IRB)-approved prospective study. All women underwent un-enhanced breast MRI. Four radiologists independently assessed FGT with MRI by subjective visual estimation according to BI-RADS. Automated observer-independent quantitative measurement of FGT with MRI was performed using a previously described measurement system. Inter-/intra-observer agreements of qualitative and quantitative FGT measurements were assessed using Cohen's kappa (k). Inexperienced readers achieved moderate inter-/intra-observer agreement and experienced readers a substantial inter- and perfect intra-observer agreement for subjective visual estimation of FGT. Practice and experience reduced observer-dependency. Automated observer-independent quantitative measurement of FGT was successfully performed and revealed only fair to moderate agreement (k = 0.209-0.497) with subjective visual estimations of FGT. Subjective visual estimation of FGT with MRI shows moderate intra-/inter-observer agreement, which can be improved by practice and experience. Automated observer-independent quantitative measurements of FGT are necessary to allow a standardized risk evaluation. • Subjective FGT estimation with MRI shows moderate intra-/inter-observer agreement in inexperienced readers. • Inter-observer agreement can be improved by practice and experience. • Automated observer-independent quantitative measurements can provide reliable and standardized assessment of FGT with MRI.

  19. Computed tomography angiography in acute stroke (revisiting the 4Ps of imaging).

    Science.gov (United States)

    Varadharajan, Shriram; Saini, Jitender; Acharya, Ullas V; Gupta, Arun Kumar

    2016-02-01

    Imaging in acute stroke has traditionally focussed on the 4Ps-parenchyma, pipes, perfusion, and penumbra-and has increasingly relied upon advanced techniques including magnetic resonance imaging to evaluate such patients. However, as per European Magnetic Resonance Forum estimates, the availability of magnetic resonance imaging scanners for the general population in India (0.5 per million inhabitants) is quite low as compared to Europe (11 per million) and United States (35 per million), with most of them only present in urban cities. On the other hand, computed tomography (CT) is more widely available and has reduced scanning duration. Computed tomography angiography of cervical and intracranial vessels is relatively simpler to perform with extended coverage and can provide all pertinent information required in such patients. This imaging review will discuss relevant imaging findings on CT angiography in patients with acute ischemic stroke through illustrated cases. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Is visual evaluation of aneurysm coiling a reliable study end point? Systematic review and meta-analysis.

    Science.gov (United States)

    Ernst, Marielle; Yoo, Albert J; Kriston, Levente; Schönfeld, Michael H; Vettorazzi, Eik; Fiehler, Jens

    2015-06-01

    Angiographic occlusion as a surrogate marker of satisfactory aneurysm treatment is commonly used in clinical trials although some pitfalls have to be considered. To investigate the inter-rater reliability of visual rating of aneurysm occlusion as study end point, we performed a systematic review and meta-analysis. Electronic databases (MEDLINE, EMBASE, PubMed, and the Cochrane Library) were searched up to June 2014. Assessment of risk for bias was based on the Quality Appraisal Tool for Studies of Diagnostic Reliability and the Guidelines for Reporting Reliability and Agreement studies. Inter-rater reliability estimates were pooled across studies using meta-analysis, and the influence of several factors (eg, imaging methods, grading scales, and occlusion rate) was tested with meta-regression. From 1193 titles, 644 abstracts and 87 full-text versions were reviewed. Twenty-six articles met the inclusion criteria and provided 77 reliability estimates. Twenty-one different rating scales were used, and statistical analysis varied. Mean inter-rater agreement of the pooled studies was substantial (κ=0.65; 95% confidence interval, 0.60-0.69). Reliability varied significantly as a function of imaging methods, grading scales, occlusion rates, and their interaction. Observer agreement substantially increased with increasing occlusion rate in digital subtraction angiography but not in MR angiography. Reliability was higher in studies using 2- or 3-value grading scales than in studies with 4-value grading scales. There is significant heterogeneity between studies evaluating the reliability of visual evaluation of aneurysm coiling. On the basis of our analysis, we found that the combination of magnetic resonance angiography, 3-value grading scale, and 2 trained raters seems most promising for usage as surrogate study end points. © 2015 American Heart Association, Inc.

  1. 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.)

  2. 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)

  3. 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.)

  4. 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.)

  5. 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.)

  6. 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.

  7. Choriocapillaris and choroidal microvasculature imaging with ultrahigh speed OCT angiography.

    Directory of Open Access Journals (Sweden)

    WooJhon Choi

    Full Text Available We demonstrate in vivo choriocapillaris and choroidal microvasculature imaging in normal human subjects using optical coherence tomography (OCT. An ultrahigh speed swept source OCT prototype at 1060 nm wavelengths with a 400 kHz A-scan rate is developed for three-dimensional ultrahigh speed imaging of the posterior eye. OCT angiography is used to image three-dimensional vascular structure without the need for exogenous fluorophores by detecting erythrocyte motion contrast between OCT intensity cross-sectional images acquired rapidly and repeatedly from the same location on the retina. En face OCT angiograms of the choriocapillaris and choroidal vasculature are visualized by acquiring cross-sectional OCT angiograms volumetrically via raster scanning and segmenting the three-dimensional angiographic data at multiple depths below the retinal pigment epithelium (RPE. Fine microvasculature of the choriocapillaris, as well as tightly packed networks of feeding arterioles and draining venules, can be visualized at different en face depths. Panoramic ultra-wide field stitched OCT angiograms of the choriocapillaris spanning ∼32 mm on the retina show distinct vascular structures at different fundus locations. Isolated smaller fields at the central fovea and ∼6 mm nasal to the fovea at the depths of the choriocapillaris and Sattler's layer show vasculature structures consistent with established architectural morphology from histological and electron micrograph corrosion casting studies. Choriocapillaris imaging was performed in eight healthy volunteers with OCT angiograms successfully acquired from all subjects. These results demonstrate the feasibility of ultrahigh speed OCT for in vivo dye-free choriocapillaris and choroidal vasculature imaging, in addition to conventional structural imaging.

  8. Choriocapillaris and choroidal microvasculature imaging with ultrahigh speed OCT angiography.

    Science.gov (United States)

    Choi, WooJhon; Mohler, Kathrin J; Potsaid, Benjamin; Lu, Chen D; Liu, Jonathan J; Jayaraman, Vijaysekhar; Cable, Alex E; Duker, Jay S; Huber, Robert; Fujimoto, James G

    2013-01-01

    We demonstrate in vivo choriocapillaris and choroidal microvasculature imaging in normal human subjects using optical coherence tomography (OCT). An ultrahigh speed swept source OCT prototype at 1060 nm wavelengths with a 400 kHz A-scan rate is developed for three-dimensional ultrahigh speed imaging of the posterior eye. OCT angiography is used to image three-dimensional vascular structure without the need for exogenous fluorophores by detecting erythrocyte motion contrast between OCT intensity cross-sectional images acquired rapidly and repeatedly from the same location on the retina. En face OCT angiograms of the choriocapillaris and choroidal vasculature are visualized by acquiring cross-sectional OCT angiograms volumetrically via raster scanning and segmenting the three-dimensional angiographic data at multiple depths below the retinal pigment epithelium (RPE). Fine microvasculature of the choriocapillaris, as well as tightly packed networks of feeding arterioles and draining venules, can be visualized at different en face depths. Panoramic ultra-wide field stitched OCT angiograms of the choriocapillaris spanning ∼32 mm on the retina show distinct vascular structures at different fundus locations. Isolated smaller fields at the central fovea and ∼6 mm nasal to the fovea at the depths of the choriocapillaris and Sattler's layer show vasculature structures consistent with established architectural morphology from histological and electron micrograph corrosion casting studies. Choriocapillaris imaging was performed in eight healthy volunteers with OCT angiograms successfully acquired from all subjects. These results demonstrate the feasibility of ultrahigh speed OCT for in vivo dye-free choriocapillaris and choroidal vasculature imaging, in addition to conventional structural imaging.

  9. Diagnosis of unruptured and ruptured aneurysms using magnetic resonance angiography

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Takeshi; Houkin, Kiyohiro; Abe, Hiroshi (Hokkaido Univ., Sapporo (Japan). School of Medicine); Kashiwaba, Takeshi

    1994-05-01

    Most previous reports have explored the efficacy of magnetic resonance angiography (MRA) as a noninvasive screening method for the detection of unruptured intracranial aneurysms and occlusive vascular disease. The purpose of this study was to assess the accuracy of three-dimensional (3D) time-of-flight (TOF) MRA in the identification of ruptured aneurysms presenting subarachnoid hemorrhage (SAH) as well as unruptured aneurysms. Sixty-two consecutive patients with 36 ruptured and 32 unruptured aneurysms were examined. MR angiograms and conventional contrast angiograms were retrospectively reviewed with regard to the relation between the detectability on MRA and size of aneurysm, location, and influence of subarachnoid hematoma. The size of ruptured aneurysms was significantly larger than that of unruptured aneurysms. Twenty-seven of 29 ruptured aneurysms in acute stage (93%) was detected on MRA, whereas 29 of 36 unruptured aneurysms (81%) and none of 4 ruptured aneurysms in subacute stage (0%) were detectable. Individual vessel visualization and image quality of MRA in patients with acute SAH were satisfactory, although in patients with subacute SAH, MRA showed poor visualization of vessels due to T1-shortening of subacute surrounding hematoma and presence of delayed vasospasm. Main causes of failure to detect aneurysms on MRA included limitation of spatial resolution, limited projections obtainable with maximum-intensity-projection (MIP) techniques and subacute hematoma simulating flow signal on MIP reconstructions. Improvement of present limitation of MRA requires higher spatial resolution, higher contrast resolution and a more adequate reconstruction method. MRA was considered to be a safe and useful examination for intracranial aneurysms especially in patients with acute SAH. (author).

  10. 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

  11. Whole-heart MR coronary angiography - first results

    International Nuclear Information System (INIS)

    Ozgun, M.; Quante, M.; Fischbach, R.; Heindel, W.; Maintz, D.; Hoffmeier, A.; Botnar, R.

    2006-01-01

    Purpose: To evaluate a new coronary MR angiography technique covering the whole coronary artery tree in one data set acquisition. Materials and methods: Six healthy volunteers and 15 patients with known CAD were examined with a navigator gated and corrected (NAV) free-breathing 3D steady-state free precession sequence covering the whole heart (WH-MRA) (TR=5.4, TE-2.7, SENSE factor=2, 160 slices, 0.75 mm reconstructed slice thickness, in-plane resolution =0.99 x 0.99 mm 2 , scan time 14 min [50% NAV efficiency]) and a vessel targeted 3D SSFP MRA sequence (t-MRA) (TR=5.6 ms, TE-2.8 ms, 20 slices of 1.5 mm reconstructed slice thickness, in-plane resolution =0.99 x 0.99 mm 2 , scan time=7 min [50% NAV efficiency]). Subjective image quality (4-point scale) and objective image quality parameters including vessel sharpness, vessel diameter and CNR were calculated for WH-MRA and t-MRA. In patients, the accuracy for detection of stenosis larger than 50% was compared to the accuracy of X-ray coronary angiography (XA), which was considered the standard. Results: WH-MRA demonstrated good vessel visibility in healthy subjects (100%) whereas vessel visibility in patients was limited (78% in an 8 segment evaluation). Vessel sharpness was inferior to that of t-MRA in patients (37 vs. 42%) but equal in healthy subjects (42%). Vessel diameter did not differ significantly between WH-MRA and t-MRA. CNR was significantly reduced for WH-MRA (CNR 7.4 vs. 11.5). The diagnostic accuracy for the detection of CAD was comparable for both MRA approaches (85.5 vs. 86.2%). Conclusion: WH-MRA allows good coronary artery visualization in healthy subjects and patients and provides a simplified scanning procedure and advantages in 3D post-processing. Regarding image parameters and the detection of CAD, the results are comparable to those acquired with t-MRA. The major disadvantage remains the high number of diagnostically insufficient images. (orig.)

  12. Assessment of coronary artery aneurysms in paediatric patients with Kawasaki disease by multidetector row CT angiography: feasibility and comparison with 2D echocardiography

    International Nuclear Information System (INIS)

    Chu, W.C.W.; Lam, W.W.M.; Mok, G.C.F.; Yam, M.; Sung, R.Y.T.

    2006-01-01

    Transthoracic ECHO is the locally accepted method for coronary surveillance of patients with Kawasaki disease but it may have limited visualization in the older child. To assess the feasibility of multidetector CT (MDCT) angiography in the follow-up of coronary artery aneurysms in children with previous Kawasaki disease. Six children (5 boys, 1 girl; mean age 11.5 years) with known Kawasaki disease and coronary artery involvement underwent CT coronary angiography using 16-detector MDCT. The visualized lengths and diameter of all coronary segments were measured. The number, size and location of coronary artery aneurysms were recorded and compared with recent ECHO. Twelve coronary artery aneurysms (seven saccular, five fusiform) were identified by MDCT angiography. One saccular aneurysm at the junction of the distal right coronary artery and posterior descending artery was not detected by ECHO while the remaining six in proximal segments were detected by both modalities. Two of five fusiform aneurysms were not detected by ECHO due to their small sizes. Excellent agreement was found between CT and ECHO for maximal diameter and length of the visualized aneurysms. MDCT angiography accurately defines coronary artery aneurysms. It is more sensitive for detecting aneurysms at distal coronary segments and fusiform aneurysms of small size

  13. The influence factors in image quality of multi-slice spiral CT coronary angiography (MSCTA)

    International Nuclear Information System (INIS)

    Zeng Huiliang; Zhu Xinjin; Liang Jianhao; Zhong Yingze; Chen Xueguang; Ou Weiqian; Wen Haomao; Li Peiwen

    2007-01-01

    Objective: To evaluate the influence of heart rate on image quality of multi-slice spiral CT coronary angiography(MSCTA) and the optimization of image reconstruction windows. Methods: Retrospectively ECG-gated MSCT coronary angiography were performed in 67 cases. The cases were divided into four groups by heart rate, groupl with heart rate less than 60 beats per minute(bpm), group 2 with heart rate 61-70 bpm, group 3 with heart rate 71-80 bpm and group 4 with heart rate over 81 bpm. The impact of heart rate on image quality of MSCTA and the optimization of image reconstruction windows were evaluated. Results: 4 coronary (RCA,LM,LAD,LCX) segments were analyzed in each patients with regard to image quality. 86.7%(112/128) of the coronary segments were sufficient for analysis in patients with heart rate less than 60 bpm,62.5%(55/88) with 61-70 bpm,40%(8/20) with 71-80 bpm and 12.5%(2/16) with heart rate over 81 bpm, respectively. There were statistically significances between every coronary segments of group 1 and 2, group 3 and 4 (P<0.05). All coronary segments of group 1 were optimally visualized on the image reconstructed at 75% image reconstruction window of' cardiac cycle; 89.5% cases at 75% in group 2; for group 3.55% of coronary artery were best presented at 75% image reconstruction window, 45% of coronary artery at 45%; All coronary segments of group 4 were optimally visualized on the image reconstructed at 45% image reconstruction window. Conclusion: Image quality of MSCT coronary angiography is highly dependent on heart rate. Coronary artery is usually best shown at 75% image reconstruction window of cardiac cycle for those with heart rate less than 70 bpm. 30%-90% image reconstruction should be performed when heart rate is over 71 bpm. (authors)

  14. 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

  15. 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

  16. 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)

  17. 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.)

  18. 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....

  19. Using flow information to support 3D vessel reconstruction from rotational angiography

    International Nuclear Information System (INIS)

    Waechter, Irina; Bredno, Joerg; Weese, Juergen; Barratt, Dean C.; Hawkes, David J.

    2008-01-01

    For the assessment of cerebrovascular diseases, it is beneficial to obtain three-dimensional (3D) morphologic and hemodynamic information about the vessel system. Rotational angiography is routinely used to image the 3D vascular geometry and we have shown previously that rotational subtraction angiography has the potential to also give quantitative information about blood flow. Flow information can be determined when the angiographic sequence shows inflow and possibly outflow of contrast agent. However, a standard volume reconstruction assumes that the vessel tree is uniformly filled with contrast agent during the whole acquisition. If this is not the case, the reconstruction exhibits artifacts. Here, we show how flow information can be used to support the reconstruction of the 3D vessel centerline and radii in this case. Our method uses the fast marching algorithm to determine the order in which voxels are analyzed. For every voxel, the rotational time intensity curve (R-TIC) is determined from the image intensities at the projection points of the current voxel. Next, the bolus arrival time of the contrast agent at the voxel is estimated from the R-TIC. Then, a measure of the intensity and duration of the enhancement is determined, from which a speed value is calculated that steers the propagation of the fast marching algorithm. The results of the fast marching algorithm are used to determine the 3D centerline by backtracking. The 3D radius is reconstructed from 2D radius estimates on the projection images. The proposed method was tested on computer simulated rotational angiography sequences with systematically varied x-ray acquisition, blood flow, and contrast agent injection parameters and on datasets from an experimental setup using an anthropomorphic cerebrovascular phantom. For the computer simulation, the mean absolute error of the 3D centerline and 3D radius estimation was 0.42 and 0.25 mm, respectively. For the experimental datasets, the mean absolute

  20. Real-time visualization of coronary interventions using VRML

    Science.gov (United States)

    Mitchell, Steven C.; Wahle, Andreas; von Birgelen, Clemens; Erbel, Raimund; Sonka, Milan

    1999-05-01

    Medical visualization is a rapidly developing field with many application areas spanning from visualization of anatomy to surgery planning, to understanding of disease processes. With increasing computer speed, medical visualization is becoming more real-time. In this paper, we present a novel application of real-time three-dimensional visualization of coronary arteries during catheter interventions that combines image information from two complementary sources: biplane x-ray contrast angiography and intravascular ultrasound (IVUS). After identification of the three-dimensional characteristics of the intravascular ultrasound pullback sequence, vessel geometry and vessel wall images are combined into a single visualization using semi-automated analysis of a corresponding pair of biplane angiography images. Visualization data are represented using the Virtual Reality Modeling Language (VRML), the code for which is automatically generated by our angiography/IVUS image processing and analysis software system. Selection of the VRML approach facilitates real-time 3-D visualization with an ability of over-the-network image processing and dissemination of results. The visualization specifics are easily modifiable in near real time to consider the immediate requirements of the end-user, the cardiologist who performs the coronary intervention.

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

    International Nuclear Information System (INIS)

    Nau, G.; Albertal, M.; Cura, F.; Padilla, L.; Candiello, A.; Torrent, F.; Peralta, S.; Belardi, J.

    2012-01-01

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

  2. 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

  3. 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.

  4. Use of optical coherence tomography to evaluate visual acuity and visual field changes in dengue fever.

    Science.gov (United States)

    Rhee, Taek Kwan; Han, Jung Il

    2014-02-01

    Dengue fever is a viral disease that is transmitted by mosquitoes and affects humans. In rare cases, dengue fever can cause visual impairment, which usually occurs within 1 month after contracting dengue fever and ranges from mild blurring of vision to severe blindness. Visual impairment due to dengue fever can be detected through angiography, retinography, optical coherence tomography (OCT) imaging, electroretinography, event electroencephalography (visually evoked potentials), and visual field analysis. The purpose of this study is to report changes in the eye captured using fluorescein angiography, indocyanine green, and OCT in 3 cases of dengue fever visual impairment associated with consistent visual symptoms and similar retinochoroidopathic changes. The OCT results of the three patients with dengue fever showed thinning of the outer retinal layer and disruption of the inner segment/outer segment (IS/OS) junction. While thinning of the retina outer layer is an irreversible process, disruption of IS/OS junction is reported to be reversible. Follow-up examination of individuals with dengue fever and associated visual impairment should involve the use of OCT to evaluate visual acuity and visual field changes in patients with acute choroidal ischemia.

  5. Contrast-enhanced MR angiography in Leriche's syndrome

    International Nuclear Information System (INIS)

    Link, J.; Steffens, J.C.; Brossmann, J.; Heller, M.; Loose, R.

    1998-01-01

    Purpose: To determine the usefulness of contrast-enhanced MR angiography for the diagnosis of Leriche's syndrome. Material and methods: Leriche's syndrome was seen in 7 patients via DSA. In [dition, contrast-enhanced MR angiography was performed (T R 7.8 ms/T E 2.1 ms, flip angle 30 , slab thickness 116 mm, slice thickness 1.82 mm, 64 partitions, FOV 500x438 mm, matrix 224x512). Results: Diagnosis of Leriche's syndrome was possible by contrast-enhanced MR angiography in each case. Visualisation of the femoral arteries was not possible in two patients by intraarterial DSA, in three other patients there was an insufficient contrast in the femoral arteries with DSA. Contrast-enhanced MR angiography revealed good visualisation of the femoral arteries in these patients. In [dition, contrast-enhanced MR angiography allowed complete visualisation of the patent lower limb arteries. In intraarterial DSA visualisation of the lower limb arteries was achieved reached in only one patient, but was incomplete. Conclusion: Contrast-enhanced MR angiography yielded the correct diagnosis of Leriche's syndrome in all 7 patients. Contrast-enhanced MR angiography was superior to DSA in the assessment of the distal run-off vessels in five of seven patients. (orig.) [de

  6. Experience with intravenous digital subtraction angiography following shunting in 4 cases of congenital heart diseases

    Energy Technology Data Exchange (ETDEWEB)

    Higashidate, Masafumi; Konno, Susumu; Sumitomo, Naokata; Ito, Sango; Kobayashi, Hiroshi

    1985-01-01

    Intravenous digital subtraction angiography (IV-DSA) was performed in two patients with Fallot's tetralogy who underwent Blalock-Taussing operation, a patient with coarctation of the aortic arch who underwent extra-anastomic bypass between the ascending aorta and the descending aorta, and a patient with stenosis of the tricuspid valve who underwent Fontan type operation (anastomosis between the right atrium and the pulmonary artery). The conventional cardiac angiography was also performed for the comparison with IV-DSA in all patients. IV-DSA revealed the thickness of the subclavian artery anastomosed by Blaloch-Taussing operation, but failed to determine the accurate thickness of the pulmonary artery required for PA-index for radical surgery in cases of Fallot's tetralogy. Bypass from the ascending aorta to the descending aorta was well visualized by IV-DSA because the heart did not overlap on the image. In cases of Fontan type operation, IV-DSA permitted the visualization of blood flow from the right atrium to the pulmonary artery and the shape of the pulmonary artery. It is concluded that IV-DSA is a less invasive, simple technique to evaluate patients' condition following shunting for congenital heart diseases, as compared to the conventional method. (Namekawa, K.).

  7. Experience with intravenous digital subtraction angiography following shunting in 4 cases of congenital heart diseases

    International Nuclear Information System (INIS)

    Higashidate, Masafumi; Konno, Susumu; Sumitomo, Naokata; Ito, Sango; Kobayashi, Hiroshi

    1985-01-01

    Intravenous digital subtraction angiography (IV-DSA) was performed in two patients with Fallot's tetralogy who underwent Blalock-Taussing operation, a patient with coarctation of the aortic arch who underwent extra-anastomic bypass between the ascending aorta and the descending aorta, and a patient with stenosis of the tricuspid valve who underwent Fontan type operation (anastomosis between the right atrium and the pulmonary artery). The conventional cardiac angiography was also performed for the comparison with IV-DSA in all patients. IV-DSA revealed the thickness of the subclavian artery anastomosed by Blaloch-Taussing operation, but failed to determine the accurate thickness of the pulmonary artery required for PA-index for radical surgery in cases of Fallot's tetralogy. Bypass from the ascending aorta to the descending aorta was well visualized by IV-DSA because the heart did not overlap on the image. In cases of Fontan type operation, IV-DSA permitted the visualization of blood flow from the right atrium to the pulmonary artery and the shape of the pulmonary artery. It is concluded that IV-DSA is a less invasive, simple technique to evaluate patients' condition following shunting for congenital heart diseases, as compared to the conventional method. (Namekawa, K.)

  8. Multiple detector-row CT angiography of the renal and mesenteric vessels

    Energy Technology Data Exchange (ETDEWEB)

    Fleischmann, Dominik. E-mail: dominik.fleischmann@univie.ac.at

    2003-03-01

    Computed tomography angiography (CTA) of the abdomen with multiple detector-row computed tomography (MD-CT) is an effective technique for minimally invasive imaging of the renal arteries and the visceral vasculature. This article reviews the clinical and technical aspects of MD-CT angiography in terms of image acquisition and reconstruction parameters, contrast medium application, and three-dimensional visualization with special attention to renal and mesenteric vascular imaging. Because of its high sensitivity to detect renal artery stenosis on the one hand, and because a normal renal CTA virtually excludes the presence of a significant renal artery stenosis on the other hand, renal CTA plays a useful role in the management of patients with suspected renovascular hypertension. Mesenteric CTA is a useful tool for visualizing normal vascular anatomy and its variants--particularly in the setting of organ transplantation. Vascular pathology, e.g. atherosclerotic disease (abdominal angina), or aneurysms of the visceral arteries are reliably assessed with CTA. Mesenteric CTA is an invaluable adjunct to abdominal CT in the setting of abdominal emergencies, because of its ability to detect the causes of acute intestinal ischemia (superior mesenteric artery embolism or thrombosis, superior mesenteric vein thrombosis). Accurate timing of the CTA acquisition and the subsequent parenchymal phase acquisition relative to the contrast medium transit time is critical to obtain excellent image quality in double-pass abdominal CT acquisitions.

  9. Subjective and objective image differences in pediatric computed tomography cardiac angiography using lower iodine concentration

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Jae-Yeon [Pusan National University Yangsan Hospital, Department of Radiology, Yangsan-si, Gyeongsangnam-do (Korea, Republic of); Pusan National University Yangsan Hospital, Research Institute for Convergence of Biomedical Science and Technology, Yangsan-si, Gyeongsangnam-do (Korea, Republic of); Choo, Ki Seok; Choi, Yoon Young; Kim, Jin Hyeok; Ryu, Hwaseong; Kim, Yong-Woo; Jeon, Ung Bae; Nam, Kyung Jin [Pusan National University Yangsan Hospital, Department of Radiology, Yangsan-si, Gyeongsangnam-do (Korea, Republic of); Han, Junhee [Pusan National University Yangsan Hospital, Division of Biostatistics, Research Institute for Convergence of Biomedical Science and Technology, Yangsan-si, Gyeongsangnam-do (Korea, Republic of)

    2017-05-15

    Several recent studies showed the optimal contrast enhancement with a low-concentration and iso-osmolar contrast media in both adult and pediatric patients. However, low contrast media concentrations are not routinely used due to concerns of suboptimal enhancement of cardiac structures and small vessels. To evaluate the feasibility of using iso-osmolar contrast media containing a low iodine dose for CT cardiac angiography at 80 kilovolts (kVp) in neonates and infants. The iodixanol 270 group consisted of 79 CT scans and the iopromide 370 group of 62 CT scans in patients ≤1 year old. Objective measurement of the contrast enhancement was analyzed and contrast-to-noise ratios of the ascending aorta and left ventricle were calculated. Regarding subjective measurement, a four-point scale system was devised to evaluate degrees of contrast enhancement, image noise, motion artifact and overall image quality of each image set. Reader performance for correctly differentiating iodixanol 270 and iopromide 370 by visual assessment was evaluated. Group objective and subjective measurements were nonsignificantly different. Overall sensitivity, specificity and diagnostic accuracy for correctly differentiating iodixanol 270 and iopromide 370 by visual assessment were 42.8%, 59%, and 50%, respectively. The application of iodixanol 270 achieved optimal enhancement for performing pediatric cardiac CT angiography at 80 kVp in neonates and infants. Objective measurements of contrast enhancement and subjective image quality assessments were not statistically different in the iodixanol 270 and iopromide 370 groups. (orig.)

  10. Multiple detector-row CT angiography of the renal and mesenteric vessels

    International Nuclear Information System (INIS)

    Fleischmann, Dominik.

    2003-01-01

    Computed tomography angiography (CTA) of the abdomen with multiple detector-row computed tomography (MD-CT) is an effective technique for minimally invasive imaging of the renal arteries and the visceral vasculature. This article reviews the clinical and technical aspects of MD-CT angiography in terms of image acquisition and reconstruction parameters, contrast medium application, and three-dimensional visualization with special attention to renal and mesenteric vascular imaging. Because of its high sensitivity to detect renal artery stenosis on the one hand, and because a normal renal CTA virtually excludes the presence of a significant renal artery stenosis on the other hand, renal CTA plays a useful role in the management of patients with suspected renovascular hypertension. Mesenteric CTA is a useful tool for visualizing normal vascular anatomy and its variants--particularly in the setting of organ transplantation. Vascular pathology, e.g. atherosclerotic disease (abdominal angina), or aneurysms of the visceral arteries are reliably assessed with CTA. Mesenteric CTA is an invaluable adjunct to abdominal CT in the setting of abdominal emergencies, because of its ability to detect the causes of acute intestinal ischemia (superior mesenteric artery embolism or thrombosis, superior mesenteric vein thrombosis). Accurate timing of the CTA acquisition and the subsequent parenchymal phase acquisition relative to the contrast medium transit time is critical to obtain excellent image quality in double-pass abdominal CT acquisitions

  11. Optical Coherence Tomography Angiography: Employing a Novel Technique for Investigation in Vogt-Koyanagi-Harada Disease

    Directory of Open Access Journals (Sweden)

    Panagiotis Giannakouras

    2017-07-01

    Full Text Available Purpose: To report a case of Vogt-Koyanagi-Harada (VKH disease and describe the imaging findings by means of optical coherence tomography angiography (OCTA. Methods: Medical and ophthalmological history, ophthalmological examination, laboratory evaluation, B-scan ultrasonography, fluorescein and indocyanine angiography, and optical coherence tomography (OCT were performed at baseline, as well as OCTA. Results: A 50-year-old healthy female presented with decreased vision in both eyes. A Topcon DRI OCT Triton Plus swept source OCT system was used to visualize and evaluate the retinal and choroidal vascular plexus. Patchy and confluent dark areas in the superficial and deep retinal capillary plexus and choriocapillaris corresponded to areas of hypoperfusion, analyzed as areas of ischemia. Conclusions and Importance: VKH disease is characterized by ocular, neurological, and integumentary findings in its complete form. We present a case of incomplete disease in a 50-year-old female evaluated by means of OCTA which is a novel technique that provides depth-resolved images of the retina and choroidal microvasculature without dye injection that allows better visualization and detailed evaluation of the retinal and choroidal vascular plexus.

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

    Science.gov (United States)

    Netwong, Y.; Krisanachinda, A.

    2016-03-01

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

  13. Using coronary CT angiography for guiding invasive coronary angiography: potential role to reduce intraprocedural radiation exposure.

    Science.gov (United States)

    Arendt, Christophe T; Tischendorf, Patricia; Wichmann, Julian L; Messerli, Michael; Jörg, Lucas; Ehl, Niklas; Gohmann, Robin F; Wildermuth, Simon; Vogl, Thomas J; Bauer, Ralf W

    2018-02-07

    We investigated the potential reduction of patient exposure during invasive coronary angiography (ICA) if the procedure had only been directed to the vessel with at least one ≥ 50% stenosis as described in the CT report. Dose reports of 61 patients referred to ICA because of at least one ≥ 50% stenosis on coronary CT angiography (CCTA) were included. Dose-area product (DAP) was documented separately for left (LCA) and right coronary arteries (RCA) by summing up the single DAP for each angiographic projection. The study population was subdivided as follows: coronary intervention of LCA (group 1) or RCA (group 2) only, or of both vessels (group 3), or further bypass grafting (group 4), or no further intervention (group 5). 57.4% of the study population could have benefitted from reduced exposure if catheterization had been directly guided to the vessel of interest as described on CCTA. Mean relative DAP reductions were as follows: group 1 (n = 18), 11.2%; group 2 (n = 2), 40.3%; group 3 (n = 10), 0%; group 4 (n = 3), 0%; group 5 (n = 28), 28.8%. Directing ICA to the vessel with stenosis as described on CCTA would reduce intraprocedural patient exposure substantially, especially for patients with single-vessel stenosis. • Patients with CAD can benefit from decreased radiation exposure during coronary angiography. • ICA should be directed solely to significant stenoses as described on CCTA. • Severely calcified plaques remain a limitation of CCTA leading to unnecessary ICA referrals.

  14. Digital subtraction angiography system evaluation with phantoms

    International Nuclear Information System (INIS)

    Wenstrup, R.S.; Sweeney, K.P.; Scholz, F.J.

    1985-01-01

    Advances in digital subtraction angiography imaging demonstrate the need for critical evaluation of the performance of digital subtraction equipment. The design of a phantom set for noninvasive assessment of the imaging quality of digital subtraction equipment is described; components include a remotely controlled transport system and individual patterns to evaluate the contrast and detail properties of the image intensifier, low-contrast sensitivity and resolution of the system, geometric distortion of image, linearity, mechanical and electronic stability of equipment, and effects of bone and bowel gas on iodine perception. The performance of an add-on digital radiographic system is presented, along with radiation exposure levels at the image intensifier for a range of radiographic techniques

  15. Multislice CT angiography of interrupted aortic arch

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-01-15

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

  16. Multidetector CT angiography in Takayasu arteritis

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-02-15

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

  17. Transbrachial artery approach for selective cerebral angiography

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-02-01

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

  18. Two-dimensional phase contrast MR angiography of the venous system of lower extremities

    International Nuclear Information System (INIS)

    Hashimoto, Hiromi; Nakatsuka, Haruki; Tsubakimoto, Mitsuo

    1994-01-01

    Two-dimensional phase contrast MR angiography (MRA) was performed in 10 healthy volunteers and 14 patients in whom deep venous occlusion was clinically suspected. In all volunteers, MRA demonstrated bilateral great saphenous veins, superficial femoral veins and popliteal veins. Deep veins in the calves were visualized in only 3 of 20 legs (15%) examined, but after applying tourniquets above the knee, they were visualized in 6 of 8 legs (75%). In 5 of 8 patients whose lower extremities were swollen, deep vein occlusions were diagnosed by MRA and in 4 patients deep vein thrombosis was confirmed by computed tomography or conventional venography. In the other 3 patients whose lower extremities were swollen and in 6 patients whose lower extremities were not swollen but who had varicose veins, MRA demonstrated patency of the deep veins. It is concluded that MRA is a non-invasive useful diagnostic technique for evaluating patency of the deep venous system of the lower extremities. (author)

  19. Two-dimensional phase contrast MR angiography of the venous system of lower extremities

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Hiromi; Nakatsuka, Haruki; Tsubakimoto, Mitsuo (Itami City Hospital, Hyogo (Japan)) (and others)

    1994-01-01

    Two-dimensional phase contrast MR angiography (MRA) was performed in 10 healthy volunteers and 14 patients in whom deep venous occlusion was clinically suspected. In all volunteers, MRA demonstrated bilateral great saphenous veins, superficial femoral veins and popliteal veins. Deep veins in the calves were visualized in only 3 of 20 legs (15%) examined, but after applying tourniquets above the knee, they were visualized in 6 of 8 legs (75%). In 5 of 8 patients whose lower extremities were swollen, deep vein occlusions were diagnosed by MRA and in 4 patients deep vein thrombosis was confirmed by computed tomography or conventional venography. In the other 3 patients whose lower extremities were swollen and in 6 patients whose lower extremities were not swollen but who had varicose veins, MRA demonstrated patency of the deep veins. It is concluded that MRA is a non-invasive useful diagnostic technique for evaluating patency of the deep venous system of the lower extremities. (author).

  20. Visual field

    Science.gov (United States)

    Perimetry; Tangent screen exam; Automated perimetry exam; Goldmann visual field exam; Humphrey visual field exam ... Confrontation visual field exam. This is a quick and basic check of the visual field. The health care provider ...

  1. Visual Impairment

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Visual Impairment KidsHealth / For Teens / Visual Impairment What's in ... with the brain, making vision impossible. What Is Visual Impairment? Many people have some type of visual ...

  2. Digital subtraction angiography in 105 living renal transplant donors

    International Nuclear Information System (INIS)

    Suh, Ho Jong; Oh, Kyung Seung; Kim, So Sun; Huh, Jin Do; Kim, Ho Joon; Chun, Byung Hee; Joh, Young Duck

    1989-01-01

    In order to analyze the number and length of the renal arteries and to evaluate abnormalities of the renal parenchyma and vessel, digital subtraction angiogram images of 105 potential renal donors (45 men and 60 women aged 17-66 years) were studied retrospectively. For the entire series, 31 donors had multiple renal arteries on one side (15 on the left, 11 on the right) and 5 donors on the both sides. 89 donors were family related either parents or siblings of recipients. The estimation of the length of the renal artery was based on the mean height of the second lumbar vertebral body (L2). The right renal artery is significant longer than on the left and measured more than the height of L2 vertebral body in 84 cases on the right and 60 cases on the left. Twenty two donors underwent right nephrectomy due to presence of multiple renal arteries on the left (N=14), proximal bifurcation of left main renal artery (N=3), and young females in reproductive age (N=5). Unexpected abnormalities found with angiogram were seen in 7 cases and they include renal artery stenosis (N=2), renal cysts (N=4) and focal infarction (N=1). In cases of the renal cysts and focal infarction, there were no serious complications related to the abnormalities. It is conclude that intra-arterial digital subtraction angiography is safe and efficient method to image renal anatomy of the potential renal donors

  3. Quantitation of left ventricular asynchrony on radionuclide angiography phase images

    International Nuclear Information System (INIS)

    Alfano, B.; Betocchi, S.; Pace, L.; Perrone-Filardi, P.; Chiariello, M.; Salvatore, M.; Naples Univ.

    1990-01-01

    Quantitation of left ventricular (LV) asynchrony is relevant in clinical cardiology, as well as in evaluating LV mechanical properties. Radionuclide angiography (RA) phase images are extensively used, and asynchrony is usually assessed by computing the standard deviation of phase angle distribution (SD). However, SD is dependent on count statistics and does not take into account the spatial distribution of asynchrony. In this study a new index to evaluate asynchrony on phase images is presented (differential uniformity parameter, DUP). DUP is based on the frequency analysis of phase images. Diagnostic accuracy and reproducibility of either SD or DUP were tested. Reproducibility was evaluated in 15 patients studied by RA twice within a few minutes. DUP showed a better reproducibility than SD. Diagnostic accuracy was estimated in 84 patients, divided into four subgroups on the basis of coronary arteriography and contrast ventriculogrpahy findings: (a) 25 control subjects, (b) 16 patients with coronary artery disease (CAD) and normal LV wall motion, (c) 23 patients with CAD and LV hypokinesia and (d) 20 patients with CAD and LV dyskinesia. Relative diagnostic ability was assessed by comparing the areas under receiver-operating characteristic curves. DUP's area was larger than SD's when group D was tested against all the other groups (DUP's area=87%±5%, SD's area=76%±7%; P<0.01). Thus, our study indicates that DUP is more reproducible and more accurate than SD in identifying patients with CAD and LV dyskinesia. (orig.)

  4. 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

  5. Value of CT angiography in diagnosis of cerebral artery aneurysms

    International Nuclear Information System (INIS)

    Eberhardt, K.E.W.; Tomandl, B.; Noemayr, A.; Huk, W.J.

    1997-01-01

    Purpose: In a clinical study 35 patients with intracranial aneurysms were examined using CT-angiography, MR-angiography (MRA) and digital subtraction angiography (DSA). The aim of the study was to establish the ability of noninvasive techniques to detect intracranial aneurysms. Material and methods: The CT examinations were performed using a spiral CT scanner and the MR investigations with a 1.5 T whole body MR-system. We used for MR-angiography Time of Flight (TOF) and Phase Contrast (PC) techniques. For postprocessing reconstructions modalities Maximum Intensity Projection (MIP), Surface and Volume Rendering Technique (VRT) techniques were used. The results were evaluated by the intraoperative findings. Results: Aneurysms up to 5 mm could be detected best using CTA and DSA. Giant aneurysms could be evaluated best using CTA. Volume rendering technique was the most useful postprocessing procedure. MRA using Time of Flight was superior compared with MRA using PC technique. (orig./AJ) [de

  6. Vascular hand-arm vibration syndrome--magnetic resonance angiography.

    Science.gov (United States)

    Poole, C J M; Cleveland, T J

    2016-01-01

    The diagnosis of vascular hand-arm vibration syndrome (HAVS) requires consistent symptoms, photographic evidence of digital blanching and sufficient exposure to hand-transmitted vibration (HTV; A(8) > 2.5 m/s2). There is no reliable quantitative investigation for distinguishing HAVS from other causes of Raynaud's phenomenon and from normal individuals. Hypothenar and thenar hammer syndromes produce similar symptoms to HAVS but are difficult to diagnose clinically and may be confused with HAVS. Magnetic resonance angiography (MRA) is a safe and minimally invasive method of visualizing blood vessels. Three cases of vascular HAVS are described in which MRA revealed occlusions of the ulnar, radial and superficial palmar arteries. It is proposed that HTV was the cause of these occlusions, rather than blows to the hand unrelated to vibration, the assumed mechanism for the hammer syndromes. All three cases were advised not to expose their hands to HTV despite one of them being at Stockholm vascular stage 2 (early). MRA should be the investigation of choice for stage 2 vascular HAVS or vascular HAVS with unusual features or for a suspected hammer syndrome. The technique is however technically challenging and best done in specialist centres in collaboration with an occupational physician familiar with the examination of HAVS cases. Staging for HAVS should be developed to include anatomical arterial abnormalities as well as symptoms and signs of blanching. Workers with only one artery supplying a hand, or with only one palmar arch, may be at increased risk of progression and therefore should not be exposed to HTV irrespective of their Stockholm stage. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. CT coronary angiography in patients with atrial fibrillation

    International Nuclear Information System (INIS)

    Kovacs, A.; Sommer, T.; Leiss, A.; Naehle, P.; Schild, H.; Flacke, S.; Probst, C.; Welz, A.

    2005-01-01

    Purpose: Reliable visualization of the coronary arteries with multislice spiral CT angiography (MSCTA) in patients with atrial fibrillation (AF) remains a challenge despite retrospective ECG gating. A recently developed new algorithm automatically compensates dynamic changes in the heart rate during the scan, thus reducing misregistration and motion artifacts. The HeartBeat-RT algorithm combines a fixed percent delay determined from the first R wave and the fixed offset delay based on the second R wave in the ECG cycle. The purpose of this study was to find out the optimal reconstruction window in MSCTA in patients with AF for each of the three major coronary arteries during the cardiac cycle. Materials and methods: 20 patients with permanent AF were imaged on a 16-slice scanner (slice collimation: 16 x 0.75 mm; rotation time 0.42 s; 140 kV; 380 mAs; 120 ml Ultravist 370 registered i.v.). The patients had not received any previous drugs for heart frequency regulation. Acquisition was started after bolus tracking of a biphasic bolus of 120 ml Ultravist 370 injected intravenously. Each coronary segment was reconstructed at 0%-90% of the cardiac cycle in increments of 10%. For image analysis we used coronary segments as defined by the American Heart Association. Two blinded independent readers assessed the image quality in terms of visibility and artifacts (five-point rating scale 1=very poor, 2=poor, 3=fair, 4=good and 5=excellent) and the degree of stenosis (five-point rating scale 1=0%, 2=1%-49%, 3=50%-74%, 4=75%-99%, 5=100%) on axial slices, multiplanar reconstructions and three-dimensional volume-rendered images. (orig.)

  8. OCT Angiography and Ellipsoid Zone Mapping of Macular Telangiectasia Type 2 From the AVATAR Study.

    Science.gov (United States)

    Runkle, Anne P; Kaiser, Peter K; Srivastava, Sunil K; Schachat, Andrew P; Reese, Jamie L; Ehlers, Justis P

    2017-07-01

    To evaluate alterations on optical coherence tomography angiography (OCT-A) and quantitatively assess alterations in the ellipsoid zone (EZ) in eyes with macular telangiectasia type 2 (MacTel type 2). The Observational Assessment of Visualizing and Analyzing Vessels With Optical Coherence Tomography Angiography in Retinal Diseases study is an institutional review board-approved prospective, observational study investigating OCT-A in macular disease. Patients underwent spectral-domain (SD)-OCT and OCT-A imaging at a single visit. SD-OCT data were analyzed using a novel OCT EZ-mapping software to obtain linear, area, and volumetric measurements of the EZ-retinal pigment epithelium (RPE) complex across the macular cube. OCT-A retinal capillary density was measured using the Optovue Avanti split-spectrum amplitude-decorrelation angiography algorithm. EZ-RPE parameters were compared to age-matched, sex-matched controls. Fourteen eyes of seven patients (mean age, 59 ± 6.5 years) were analyzed. Mean visual acuity was 20/45 (range, 20/20-20/150). EZ-RPE central foveal mean thickness was 27.8 ± 6.7 μm, EZ-RPE central foveal thickness was 22.1 ± 21.6 μm, EZ-RPE central foveal area was 0.17 ± 0.04 mm2, and EZ-RPE central subfield volume was 0.017 ± 0.012 mm3. Each of these measurements was significantly inversely correlated with visual acuity (P OCT-A showed a reduced parafoveal vessel density of 50.8% temporally compared to 53.8% nasally (P = 0.01) in the superficial vascular plexus. In the deep vascular plexus, similar findings were noted with a parafoveal vessel density of 56.7% temporally and 58.8% nasally (P = 0.01). Abnormalities in EZ-RPE thickness, area, and volume are correlated with visual acuity in MacTel type 2, and may provide quantitative markers to measure disease progression and treatment response. OCT-A was a useful adjunct for determining disease severity.

  9. Computed tomography angiography in the investigation of carotid stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Goddard, A.J.P.; Mendelow, A.D.; Birchall, D

    2001-07-01

    The assessment of carotid atherosclerotic disease is an essential pre-requisite for determining a patients suitability for carotid endarterectomy to prevent ischaemic stroke. Catheter angiography is regarded as the most accurate investigative tool for this purpose. However, with its finite morbidity and invasiveness, there is an increasing reliance upon non-invasive methods to accurately assess carotid disease. We present a review of the technique and applications of computed tomography angiography. Goddard, A.J. P.et al. (2001)

  10. Digital subtraction angiography in pediatric cerebrovascular occlusive disease

    International Nuclear Information System (INIS)

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

    1984-01-01

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

  11. Diagnostic accuracy of dual-source CT coronary angiography in patients with atrial fibrillation: Meta analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Gang, E-mail: cjr.sungang@vip.163.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Li, Min [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Jiang, Zhi-wei [Department of Health Statistics, School of Public Health, Fourth Military Medical University, No. 169, Changle West Road, Xi’an, Shaanxi 710032 (China); Xu, Lin [Department of Medical Cardiology, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Peng, Zhao-hui; Ding, Juan; Li, Li [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Jin, Zhi-tao [Department of Cardiology, General Hospital of the Second Artillery, Beijing 100088 (China)

    2013-10-01

    Rationale and objective: To synthesize the available data to underscore the diagnostic accuracy of dual-source CT (DSCT) coronary angiography in patients with atrial fibrillation (AF). Materials and methods: We searched in the electronic databases of PubMed for all published studies that examined patients with AF using DSCT. We used an exact binomial rendition of the bivariate mixed-effects regression model to synthesize the diagnostic data. Results: The positive and negative likelihood ratios (LRs) at the patient level were 6.0 (CI, 3.6–10.1) and 0.03(CI, 0.004–0.2), respectively. The negative predictive values higher than 90% were available for a CAD prevalence <78%. The pooled vessel- and segment-level estimates showed higher positive and negative LRs than the patient-level estimates (15.3 [CI, 9.8–23.9] and 0.1 [CI, 0.07–0.3]; 25.1 [CI, 10.8–58.5] and 0.2 [CI, 0.2–0.3], respectively). No statistically significant heterogeneity between studies and publication bias were found at the patient level estimate. A sensitivity analysis showed that no study influenced the pooled results larger than 0.02. Conclusions: Cardiac angiography with DSCT can be applied as an imaging test for ruling out CAD in patient with AF. However, DSCT angiography may be not an effective tool for risk stratification for the high negative LR at the artery and segment levels.

  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. Diagnosis of preoperative staging of bladder cancer by CT and angiography

    International Nuclear Information System (INIS)

    Munechika, Hirotsugu; Saito, Kazuhiko; Tanaka, Osamu; Tomiie, Fumitaka; Aihara, Toshinori

    1982-01-01

    The accuracy of computed tomography (CT) and angiography in defining the extent of local invasion was studied retrospectively in 19 patients with surgically proven carcinoma of the bladder. The overall accuracy of CT and angiographic staging in these cases was 54 percent and 47 percent respectively. The diagnosis of carcinoma of the bladder by CT tended to do overstaging rather than understaging. A tangential view of the tumor-bearing area by the selective internal iliac arteriography allows an accurate estimation of the perivesical tumor extension. The topographic diagnosis should be made by CT prior to the angiographic study. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-15

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

  15. A comparison between dual axis rotational coronary angiography and conventional coronary angiography.

    Science.gov (United States)

    Grech, Marvin; Debono, Joseph; Xuereb, Robert G; Fenech, Albert; Grech, Victor

    2012-10-01

    Coronary angiography remains the gold standard for the investigation of coronary artery disease, and is carried out in multiple, predefined stationary views, at different angulations around the patient, for both left and right coronary arteries. Dual axis rotational coronary angiography (DARA) is an alternative technique wherein the c-arm rotates around the patient in a preprogrammed single acquisition, exposing the entire coronary artery at different angulations. The DARA system has been recently installed in the Cardiac Catheterisation Suite at Mater Dei Hospital, Malta, where a monoplane and a biplane machine are available. This study was carried out in order to compare DARA with conventional single and biplane coronary imaging, with respect to radiation dose, contrast loads, and procedure time. This study was carried out over the period from September to December 2010. Four hundred sixty-three patients were studied. Patients referred for the investigation of native coronary anatomy, for whatever indication, were consented and included, and randomly assigned to one of four groups depending on which machine and modality was used: monoplane conventional, monoplane DARA, biplane conventional, and biplane DARA. DARA was statistically significantly superior in dose area product, fluoroscopy time, amount of contrast used, and procedure time. These reductions ranged between 12 (contrast used) and 71% (procedure time). The advantages of such systems are obvious to both patient and healthcare provider, and DARA may prove to be an important and useful tool in the refinement of diagnostic coronary angiography by reducing patient contrast and radiation doses and reducing procedure time. Copyright © 2011 Wiley Periodicals, Inc.

  16. 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.

  17. 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

  18. Parenchymal abnormalities in cerebral venous thrombosis: findings of magnetic resonance imaging and magnetic resonance angiography

    International Nuclear Information System (INIS)

    Ferreira, Clecia Santos; Pellini, Marcos; Boasquevisque, Edson; Souza, Luis Alberto M. de

    2006-01-01

    Objective: to determine the frequency and localization of parenchymal abnormalities in cerebral venous thrombosis on magnetic resonance imaging and magnetic resonance angiography as well as their correlation with the territory and affected venous drainage. Materials and methods: retrospective analysis (1996 to 2004) of 21 patients (3 male and 18 female) age range between 3 and 82 years (mean 40 years, median 36 years) with clinical and radiological diagnosis of cerebral venous thrombosis on magnetic resonance imaging and magnetic resonance angiography in 2D PC, 3D PC and contrast-enhanced 3D TOF sequences. The statistical analysis was performed with the qui-square test. Four patients had follow-up exams and three patients underwent digital subtraction angiography. Results: main predisposing factors were: infection, use of oral contraceptives, hormone replacement therapy and collagenosis. Predominant symptoms included: focal deficit, headache, alteration of consciousness level and seizures. Most frequent parenchymal manifestations were: cortical/subcortical edema or infarct, venous congestion and collateral circulation, meningeal enhancement and thalamic and basal ganglia edema or infarct. Occlusion occurred mainly in superior sagittal, left transverse, left sigmoid and straight sinuses. Cavernous sinus and cortical veins thrombosis are uncommon events. Conclusion: cerebral venous thrombosis is an uncommon cause of stroke, with favorable prognosis because of its reversibility. Diagnosis is highly dependent on the radiologist capacity to recognize the presentations of this disease, principally in cases where the diagnosis is suggested by parenchymal abnormalities rather than necessarily by visualization of the thrombus itself. An accurate and rapid diagnosis allows an immediate treatment, reducing the morbidity and mortality rates. (author)

  19. Optimal image reconstruction intervals for non-invasive coronary angiography with 64-slice CT

    Energy Technology Data Exchange (ETDEWEB)

    Leschka, Sebastian; Husmann, Lars; Desbiolles, Lotus M.; Boehm, Thomas; Marincek, Borut; Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Gaemperli, Oliver; Schepis, Tiziano; Koepfli, Pascal [University Hospital Zurich, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiovascular Center, Zurich (Switzerland); University of Zurich, Center for Integrative Human Physiology, Zurich (Switzerland)

    2006-09-15

    The reconstruction intervals providing best image quality for non-invasive coronary angiography with 64-slice computed tomography (CT) were evaluated. Contrast-enhanced, retrospectively electrocardiography (ECG)-gated 64-slice CT coronary angiography was performed in 80 patients (47 male, 33 female; mean age 62.1{+-}10.6 years). Thirteen data sets were reconstructed in 5% increments from 20 to 80% of the R-R interval. Depending on the average heart rate during scanning, patients were grouped as <65 bpm (n=49) and {>=}65 bpm (n=31). Two blinded and independent readers assessed the image quality of each coronary segment with a diameter {>=}1.5 mm using the following scores: 1, no motion artifacts; 2, minor artifacts; 3, moderate artifacts; 4, severe artifacts; and 5, not evaluative. The average heart rate was 63.3{+-}13.1 bpm (range 38-102). Acceptable image quality (scores 1-3) was achieved in 99.1% of all coronary segments (1,162/1,172; mean image quality score 1.55{+-}0.77) in the best reconstruction interval. Best image quality was found at 60% and 65% of the R-R interval for all patients and for each heart rate subgroup, whereas motion artifacts occurred significantly more often (P<0.01) at other reconstruction intervals. At heart rates <65 bpm, acceptable image quality was found in all coronary segments at 60%. At heart rates {>=}65 bpm, the whole coronary artery tree could be visualized with acceptable image quality in 87% (27/31) of the patients at 60%, while ten segments in four patients were rated as non-diagnostic (scores 4-5) at any reconstruction interval. In conclusion, 64-slice CT coronary angiography provides best overall image quality in mid-diastole. At heart rates <65 bpm, diagnostic image quality of all coronary segments can be obtained at a single reconstruction interval of 60%. (orig.)

  20. Optical Coherence Tomography Angiography Characteristics of Iris Melanocytic Tumors.

    Science.gov (United States)

    Skalet, Alison H; Li, Yan; Lu, Chen D; Jia, Yali; Lee, ByungKun; Husvogt, Lennart; Maier, Andreas; Fujimoto, James G; Thomas, Charles R; Huang, David

    2017-02-01

    To evaluate tumor vasculature with optical coherence tomography angiography (OCTA) in malignant iris melanomas and benign iris lesions. Cross-sectional observational clinical study. Patients with iris lesions and healthy volunteers. Eyes were imaged using OCTA systems operating at 1050- and 840-nm wavelengths. Three-dimensional OCTA scans were acquired. Iris melanoma patients treated with radiation therapy were imaged again after I-125 plaque brachytherapy at 6 and 18 months. OCT and OCTA images, qualitative evaluation of iris and tumor vasculature, and quantitative vessel density. One eye each of 8 normal volunteers and 9 patients with iris melanomas or benign iris lesions, including freckles, nevi, and an iris pigment epithelial (IPE) cyst, were imaged. The normal iris has radially oriented vessels within the stroma on OCTA. Penetration of flow signal in normal iris depended on iris color, with best penetration seen in light to moderately pigmented irides. Iris melanomas demonstrated tortuous and disorganized intratumoral vasculature. In 2 eyes with nevi there was no increased vascularity; in another, fine vascular loops were noted near an area of ectropion uveae. Iris freckles and the IPE cyst did not have intrinsic vascularity. The vessel density was significantly higher within iris melanomas (34.5%±9.8%, P iris nevi (8.0%±1.4%) or normal irides (8.0%±1.2%). Tumor regression after radiation therapy for melanomas was associated with decreased vessel density. OCTA at 1050 nm provided better visualization of tumor vasculature and penetration through thicker tumors than at 840 nm. But in very thick tumors and highly pigmented lesions even 1050-nm OCTA could not visualize their full thickness. Interpretable OCTA images were obtained in 82% of participants in whom imaging was attempted. This is the first demonstration of OCTA in iris tumors. OCTA may provide a dye-free, no-injection, cost-effective method for monitoring a variety of tumors, including iris

  1. Expert panel vs decision-analysis recommendations for postdischarge coronary angiography after myocardial infarction.

    Science.gov (United States)

    Kuntz, K M; Tsevat, J; Weinstein, M C; Goldman, L

    1999-12-15

    Expert panels and decision-analytic techniques are increasingly used to determine the appropriateness of medical interventions, but these 2 approaches use different methods to process evidence. To compare expert panel appropriateness ratings of coronary angiography after myocardial infarction (from the time of hospital discharge to 12 weeks after infarction) with the health gains and cost-effectiveness predicted by a decision-analytic model. Comparison of the degree of importance of the clinical variables considered in expert panel appropriateness ratings vs a previously published decision-analytic model. Identification of 36 clinical scenarios from the expert panel that could be simulated by the decision-analytic model. Appropriateness score and appropriateness classification (expert panel) vs gain in quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratio (decision-analytic model). The most important clinical variables were similar in the 2 approaches, with the exercise tolerance test result exerting the greatest leverage on strength of recommendation for angiography. Among the expert panel clinical scenarios considered to be appropriate for coronary angiography that could be simulated in the decision-analysis model, the median (interquartile range) health gain and incremental cost-effectiveness ratio were 0.59 (0.41-0.76) QALYs and $27000 ($23000-$35000) per QALY gained, respectively. Among the clinical scenarios that expert panels considered inappropriate, the corresponding medians (interquartile ranges) were 0.24 (0.19-0.34) QALYs and $54000 ($36000-$58000) per QALY gained. The Spearman rank correlation between appropriateness score and QALY gain was 0.58 (Pappropriateness score and estimated incremental cost-effectiveness ratios was -0.66 (Pappropriateness score and both the health gain and the incremental cost-effectiveness ratio of coronary angiography compared with no angiography in the convalescent phase of acute myocardial infarction

  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. MR imaging and angiography in tuberculous meningitis

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-02-01

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

  4. Localization strategy for magnetic resonance coronary angiography

    International Nuclear Information System (INIS)

    Cheng Liuquan; Gao Yuangui; Sun Wei; Sheng Fugeng; Cai Youquan

    2003-01-01

    Objective: To develop a localization strategy for magnetic resonance coronary angiography (MRCA). Methods: In 89 subjects, the standard 4-chamber view and long-axis view of left and right ventricle were acquired using Fast-Imaging-Employing-Steady-State-Acquisition (FIESTA) sequence in CINE mode, and the trigger-delay time for mid-diastolic phase was determined. Coronary vessels including right coronary artery (RCA), left main (LM), left anterior descending (LAD), and left circumflex (LCX) were localized and imaged using 3- dimensional fat-suppressed FIESTA sequence during end-expiration. The reproducibility of the localization strategy was evaluated by taking the standard of coronary segmentation system recommended by American Heart Association. Results: Eighty-six subjects completed the examination with full respiratory co-operation and the indication ratio was 96.63%. Nine planes were optimized as the standard to target the main branches of coronary arteries, and a comprehensive reproducibility reached 100% in demonstrating the proximal and middle segment of RCA (AHA-18, 19), LM (AHA-1, 2), proximal and middle segment of LAD (AHA-3, 5, 7), and proximal LCX (AHA-10). The reproducibility for the demonstration of distal segments of LAD, LCX, and RCA (AHA-9, 14, 21) was 94.19%, 72.09%, and 96.51%, respectively. Conclusion: This is a simple and practical localization strategy for MRCA. It could image the proximal and middle segments of the coronary arteries with good reproducibility, which indicates the potential for clinical application

  5. Early use of coronary angiography and intervention.

    Science.gov (United States)

    McCullough, P A; O'Neill, W W

    1999-05-01

    In this article we have outlined the current rationale and role of invasive management in ACS. For the majority of patients with ACS, who are either at high risk or unstable, invasive management is a critical element in breaking the sequence of recurrent ischemia leading to early cardiac events (Fig. 11). Secular trends in the care of cardiovascular patients predict even more sophisticated, invasive methods of treating coronary occlusion in the future. A futurist's view on this subject may envision the following type of scenario. A patient with prior CAD experiences persistent chest pain and notifies the emergency medical system. The paramedics arrive, and perform a rapid fingerstick cardiac biomarker panel and ECG. The results are interpreted by an emergency physician via a telecommunication system, and the patient is determined to be at high risk. He or she is triaged to a center capable of angioplasty and bypass surgery. On the way to the hospital, the patient is treated with aspirin, IV heparin, and an IV glycoprotein IIb/IIIa inhibitor. The patient undergoes triage angiography within 1 hour of hospital arrival, culprit lesion(s) are identified, and a revascularization plan is made--setting a critical pathway that is definitive. This vision is not far off on the horizon. We anticipate additional clinical trial results will help form the decision points in this optimal treatment scenario, which for a large proportion of patients will involve invasive management.

  6. Comparison of anterior segment optical coherence tomography angiography and fluorescein angiography for iris vasculature analysis.

    Science.gov (United States)

    Zett, Claudio; Stina, Deborah M Rosa; Kato, Renata Tiemi; Novais, Eduardo Amorim; Allemann, Norma

    2018-04-01

    The aim of this study is to perform imaging of irises of different colors using spectral domain anterior segment optical coherence tomography angiography (AS-OCTA) and iris fluorescein angiography (IFA) and compare their effectiveness in examining iris vasculature. This is a cross-sectional observational clinical study. Patients with no vascular iris alterations and different pigmentation levels were recruited. Participants were imaged using OCTA adapted with an anterior segment lens and IFA with a confocal scanning laser ophthalmoscope (cSLO) adapted with an anterior segment lens. AS-OCTA and IFA images were then compared. Two blinded readers classified iris pigmentation and compared the percentage of visible vessels between OCTA and IFA images. Twenty eyes of 10 patients with different degrees of iris pigmentation were imaged using AS-OCTA and IFA. Significantly more visible iris vessels were observed using OCTA than using FA (W = 5.22; p Iris pigmentation was negatively correlated to the percentage of visible vessels in both imaging methods (OCTA, rho = - 0.73, p iris vasculature. In both AS-OCTA and IFA, iris pigmentation caused vasculature imaging blockage, but AS-OCTA provided more detailed iris vasculature images than IFA. Additional studies including different iris pathologies are needed to determine the most optimal scanning parameters in OCTA of the anterior segment.

  7. ACCURACY OF SPIRAL CT RENAL ANGIOGRAPHY OVER CONVENTIONAL ANGIOGRAPHY IN LIVING RENAL DONORS

    Directory of Open Access Journals (Sweden)

    Malle Vijaya Kumar

    2016-10-01

    Full Text Available BACKGROUND Potential donors for renal transplantation undergo an exhaustive pretty operative examination including medical assessment, laboratory testing and radiological imaging. The goal of imaging in these subjects is to delineate the kidneys and their vascular anatomy to determine if the subject is a suitable donor nephrectomy candidate and if so to assess which kidney maybe technically easier to transplant. This traditional imaging workup has consisted of two examinations, the IV Urogram (IVU and renal arteriography. MATERIALS AND METHODS Totally 18 healthy adults who were potential renal donors were taken for spiral CT angiography. The study was conducted in Viswabharathi Medical College, Penchikalapadu, Kurnool, Andhra Pradesh, between May 2015 and May 2016. RESULTS In the present study, supernumerary renal arteries were present in 7 cases (38.8% and consisted of one artery in 4 cases (11.1% two arteries in 3 cases (16.6%. Early branching of the main renal artery was seen in one case (2.7% venous anomaly in the form of retroaortic renal vein. Nonvascular abnormality noted in one case in the form of simple renal cyst in right upper pole (2.7%. Overall, CTA sensitivity, specificity and accuracy are 100%. In one case, axial sections could not find early branching, however, it was depicted in MIPS. CONCLUSION It is superior to conventional angiography in demonstrating accessory renal artery when it is arising from aorta immediately behind the main renal artery in anteroposterior direction and incidental findings like aortic calcifications, renal vein anomalies and renal cysts.

  8. DIAGNOSTIC ACCURACY OF MAGNETIC RESONANCE ANGIOGRAPHY FOR UNRUPTURED CEREBRAL ANEURYSMS IN CORRELATION WITH DIGITAL SUBTRACTION ANGIOGRAPHY

    Directory of Open Access Journals (Sweden)

    Aleksandra Aracki-Trenkić

    2015-09-01

    Full Text Available Intracranial aneurysm is a focal, abnormal dilation of an artery of the brain. Magnetic resonance angiography (MRA is a non-invasive technique for vascular imaging and is thus widely used for screening for intracranial vascular lesions. The aim of the study was to show the diagnostic accuracy of 3D Time-of-Flight (3D TOF MRA in the detection of unruptured cerebral aneurysms with the use of digital subtraction angiography (DSA as the gold standard. A total of 2.612 consecutive patients underwent 3DTOF MRA. It showed unruptured aneurysms in 94 (3.6% patients. They included 68 women and 26 men ranging in age from 29 to 76 years (mean, 52.5 years. Twenty-six of them, 20 women and 6 men, underwent DSA. The Mann-Whitney U test was used for the correlation of size. Fisher’s test was used for the correlation of location. The statistical level of significance was set at p0.05 of aneurysms between TOF MRA and DSA. MRA is an accurate and non-invasive method for diagnosis of unruptured intracranial aneurysms. The results of study show the compatibility of MRA findings, the location and the size of an aneurysm in comparison with the “gold standard” – cerebral DSA.

  9. The use of angiography in pediatric blunt abdominal trauma patients.

    Science.gov (United States)

    Fenton, Stephen J; Sandoval, Kristin N; Stevens, Austin M; Scaife, Eric R

    2016-08-01

    Angiography is a common treatment used in adults with blunt abdominal trauma and/or severe pelvic fractures. The Committee on Trauma of the American College of Surgeons has recently advocated for this resource to be urgently available at pediatric trauma centers; however, its usefulness in the pediatric setting is unclear. The purpose of this study was to determine the incidence of angiography in the treatment of blunt abdominal trauma among injured children. An analysis was performed using an established public use data set of children (younger than 18 years) treated at 20 participating trauma centers for blunt torso trauma through the Pediatric Emergency Care Applied Research Network. Patients who underwent angiography of the abdomen or pelvis were identified and analyzed. Of the 12,044 children evaluated for blunt abdominal trauma included within the data set, 973 sustained abdominopelvic injuries. Of these, only 26 (3%) underwent angiography. The median age was 14 years, 65% were males, with a mortality rate of 19%. Overall, 29 angiographic procedures were performed: 21 abdominal, 8 pelvic, with 3 patients undergoing both abdominal and pelvic. Eleven patients underwent embolization of a bleeding vessel, all of which were related to the spleen. No hepatic, renal, or pelvic vessels required embolization. The median time to angiography from emergency department evaluation was 7.3 hours. In addition to angiography, 50% also required surgical intervention, of which 31% underwent a laparotomy. Thirty-five percent of these patients required blood product transfusion, and 42% were admitted to the intensive care unit. The emergent use of angiography with embolization is uncommon in pediatric patients with blunt abdominal injuries. The requirement that pediatric trauma centers have access to interventional radiology within 30 minutes may be unnecessary. Epidemiologic study, level III; therapeutic study, level IV.

  10. Role of multi-slice CT coronary angiography in evaluating the different patterns of coronary artery disease in patients with unstable angina

    Directory of Open Access Journals (Sweden)

    Gamal Eldine M. Niazi

    2015-09-01

    Conclusion: Non-invasive multi-slice CT coronary angiography is a reliable technique of high ability to detect coronary artery disease and estimate the degree of obstruction, number of affected arteries and the pattern of their affection and can be used in workup in patients with unstable angina.

  11. 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

  12. Coexistent coronary artery disease or myocardial bridging in patients with hypertrophic cardiomyopathy using coronary CT angiography

    International Nuclear Information System (INIS)

    Lee, Jae Hwan; Chun, Eun Ju; Kim, Yeo Koon; Yoo, Jin Young; Choi, Sang Il; Choi, Dong Ju

    2015-01-01

    To evaluate the prevalence of coexistent coronary artery disease (CAD) or myocardial bridging (MB) in patients with hypertrophic cardiomyopathy (HCM) using coronary CT angiography (CCTA) and assess the role of CCTA. The prevalence of obstructive CAD (> 50% luminal reduction) and MB (partial and full encasement) were assessed in 150 patients with HCM diagnosed by clinical findings, electrocardiography, and echocardiography of 19588 consecutive patients who underwent CCTA for suspected CAD. The overall feasibility of coronary artery visualization was 98.9% with CCTA. In patients with HCM, the prevalence of obstructive CAD and MB (14.7% partial and 28.0% full encasement) were 23.3% and 42.7%, respectively. Age, hypertension, family history of premature CAD, Framingham risk score and severe chest pain were associated with CAD, whereas male gender and septal type were associated with MB (all p < 0.05). In comparison to invasive coronary angiography (n = 37), the diagnostic accuracy of CCTA for the detection of CAD and full encasement MB was 89.2% and 86.5%, respectively. One-quarter of patients with HCM had coexistent obstructive CAD or full encasement MB. CCTA can be a feasible and accurate noninvasive imaging modality for the detection of CAD and MB in patients with HCM

  13. Coexistent coronary artery disease or myocardial bridging in patients with hypertrophic cardiomyopathy using coronary CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Hwan; Chun, Eun Ju; Kim, Yeo Koon; Yoo, Jin Young; Choi, Sang Il; Choi, Dong Ju [Seoul National University Bundang Hospital, Seongnam (Korea, Republic of)

    2015-07-15

    To evaluate the prevalence of coexistent coronary artery disease (CAD) or myocardial bridging (MB) in patients with hypertrophic cardiomyopathy (HCM) using coronary CT angiography (CCTA) and assess the role of CCTA. The prevalence of obstructive CAD (> 50% luminal reduction) and MB (partial and full encasement) were assessed in 150 patients with HCM diagnosed by clinical findings, electrocardiography, and echocardiography of 19588 consecutive patients who underwent CCTA for suspected CAD. The overall feasibility of coronary artery visualization was 98.9% with CCTA. In patients with HCM, the prevalence of obstructive CAD and MB (14.7% partial and 28.0% full encasement) were 23.3% and 42.7%, respectively. Age, hypertension, family history of premature CAD, Framingham risk score and severe chest pain were associated with CAD, whereas male gender and septal type were associated with MB (all p < 0.05). In comparison to invasive coronary angiography (n = 37), the diagnostic accuracy of CCTA for the detection of CAD and full encasement MB was 89.2% and 86.5%, respectively. One-quarter of patients with HCM had coexistent obstructive CAD or full encasement MB. CCTA can be a feasible and accurate noninvasive imaging modality for the detection of CAD and MB in patients with HCM.

  14. Optical Coherence Tomography and Optical Coherence Tomography Angiography in Monitoring Coats’ Disease

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    Wojciech Hautz

    2017-01-01

    Full Text Available Purpose. The aim of this study was to evaluate the usefulness of optical coherence tomography (OCT and optical coherence tomography angiography (OCTA in monitoring pediatric patients with Coats’ disease. Material and Methods. This retrospective study included 9 Caucasian patients receiving treatment for Coats’ disease at the Children’s Memorial Health Institute Ophthalmology Department between December 2014 and May 2016. The course of the disease was monitored with OCTA in combination with OCT and fluorescein angiography (FA. Results. OCT B-scans obtained in all patients correlated with FA findings. Reliable OCTA images were obtained in 8 patients. In one patient, numerous artifacts due to poor visual acuity and retinal detachment confounded the interpretation of findings. Conclusions. OCTA and OCT, in combination with FA, are useful in Coats’ disease diagnostics and treatment monitoring. As noninvasive methods, OCT and OCTA may be performed more often than FA, which enable precise monitoring of the disease and making decisions as to its further treatment.

  15. Remapping of digital subtraction angiography on a standard fluoroscopy system using 2D-3D registration

    Science.gov (United States)

    Alhrishy, Mazen G.; Varnavas, Andreas; Guyot, Alexis; Carrell, Tom; King, Andrew; Penney, Graeme

    2015-03-01

    Fluoroscopy-guided endovascular interventions are being performing for more and more complex cases with longer screening times. However, X-ray is much better at visualizing interventional devices and dense structures compared to vasculature. To visualise vasculature, angiography screening is essential but requires the use of iodinated contrast medium (ICM) which is nephrotoxic. Acute kidney injury is the main life-threatening complication of ICM. Digital subtraction angiography (DSA) is also often a major contributor to overall patient radiation dose (81% reported). Furthermore, a DSA image is only valid for the current interventional view and not the new view once the C-arm is moved. In this paper, we propose the use of 2D-3D image registration between intraoperative images and the preoperative CT volume to facilitate DSA remapping using a standard fluoroscopy system. This allows repeated ICM-free DSA and has the potential to enable a reduction in ICM usage and radiation dose. Experiments were carried out using 9 clinical datasets. In total, 41 DSA images were remapped. For each dataset, the maximum and averaged remapping accuracy error were calculated and presented. Numerical results showed an overall averaged error of 2.50 mm, with 7 patients scoring averaged errors < 3 mm and 2 patients < 6 mm.

  16. Characterization of rat model of acute anterior uveitis using optical coherence tomography angiography

    Science.gov (United States)

    Choi, Woo June; Pepple, Kathryn L.; Zhi, Zhongwei; Wang, Ruikang K.

    2015-03-01

    Uveitis, or ocular inflammation, is a cause of severe visual impairment. Rodent models of uveitis are powerful tools used to investigate the pathological mechanisms of ocular inflammation and to study the efficacy of new therapies prior to human testing. In this paper, we report the utility of spectral-domain optical coherence tomography (SD-OCT) angiography in characterizing the inflammatory changes induced in the anterior segment of a rat model of uveitis. Acute anterior uveitis (AAU) was induced in two rats by intravitreal injection of a killed mycobacterial extract. One of them received a concurrent periocular injection of steroids to model a treatment effect. OCT imaging was performed prior to inflammation induction on day 0 (baseline), and 2 days post-injection (peak inflammation). Baseline and inflamed images were compared. OCT angiography identified swelling of the cornea, inflammatory cells in the anterior and posterior chambers, a fibrinous papillary membrane, and dilation of iris vessels in the inflamed eyes when compared to baseline images. Steroid treatment was shown to prevent the changes associated with inflammation. This is a novel application of anterior OCT imaging in animal models of uveitis, and provides a high resolution, in vivo assay for detecting and quantifying ocular inflammation and the response to new therapies.

  17. A feasibility study for compressed sensing combined phase contrast MR angiography reconstruction

    Science.gov (United States)

    Lee, Dong-Hoon; Hong, Cheol-Pyo; Lee, Man-Woo; Han, Bong-Soo

    2012-02-01

    Phase contrast magnetic resonance angiography (PC MRA) is a technique for flow velocity measurement and vessels visualization, simultaneously. The PC MRA takes long scan time because each flow encoding gradients which are composed bipolar gradient type need to reconstruct the angiography image. Moreover, it takes more image acquisition time when we use the PC MRA at the low-tesla MRI system. In this study, we studied and evaluation of feasibility for CS MRI reconstruction combined PC MRA which data acquired by low-tesla MRI system. We used non-linear reconstruction algorithm which named Bregman iteration for CS image reconstruction and validate the usefulness of CS combined PC MRA reconstruction technique. The results of CS reconstructed PC MRA images provide similar level of image quality between fully sampled reconstruction data and sparse sampled reconstruction using CS technique. Although our results used half of sampling ratio and do not used specification hardware device or performance which are improving the temporal resolution of MR image acquisition such as parallel imaging reconstruction using phased array coil or non-cartesian trajectory, we think that CS combined PC MRA technique will be helpful to increase the temporal resolution and at low-tesla MRI system.

  18. Cerebral angiography in patients with complicated migraine

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  19. Visual Culture and Visual Literacy

    Directory of Open Access Journals (Sweden)

    Sibel Onursoy

    2017-03-01

    Full Text Available Recently visual literacy gains importance in the context of understanding the rising visual culture products, thinking about them and producing these products. The purpose of this article examines the concept of visual literacy that is the relationship with visual culture depending on the literature. Visual literacy is one of the multiple literatures that emerge from the development of information and information dissemination forms. Visual literacy is an interdisciplinary concept and associated with some areas, such as graphic design, visual arts, architectural engineering, industrial product design, visual communication and media literacy. Visual culture covers every human product, so visual products that we face in everyday life and visual realities with abundant alternatives constitute our daily life itself. Sometimes, this confusing visual understanding creates a gap between contemporary cultural richness and what can be observed.

  20. Comparison of CO2 DSA and conventional angiography using non-ionic contrast media in lower extremity angiography

    International Nuclear Information System (INIS)

    Kim, Jae Kyu; Park, Sung Jae; Koh, Seok Wan; Seo, Jeong Jin; Kang, Heoung Keun; Chung, Hyon De

    1994-01-01

    The purpose of this study is to compare CO 2 DSA and nonionic contrast media angiography in respect to the quality of the opacification of collaterals and incidence of side-effects in peripheral occlusive arterial disease. Sixteen patients who were suspected to have peripheral occlusive arterial disease were performed angiography with nonionic contrast media and CO 2 at the same location with the same catheter. The causes of the lesions were atherosclerosis(n=7) and Buerger's disease(n=9). CO 2 DSA was compared with nonionic contrast media angiography in respect to the quality of image in the diagnosis of the lesions, opacifications of collaterals and side-effects. In atherosclerosis; quality of the images of CO 2 DSA was same as that of nonionic contrast media angiography in 6 patients and was poor in 1 patient; opacifications of collaterals of CO 2 DSA were same as that of nonionic contrast media angiography in 5 patients and was poor in 2 patients. In Buerger's disease; quality of the images of CO 2 DSA was same as that of nonionic contrast media angiography in 2 patients and was poor in 7 patients; opacifications of collaterals of CO 2 DSA were same as that of nonionic contrast media angiography in 1 patient and was poor in 8 patients. Leg pain was the only side-effect after CO 2 injection occurring in 4 out of 16 patients. CO 2 could be used as safe contrast media in patient with risk factors for nonionic contrast media and for diagnosis of the atherosclerosis in lower extremity. For the procedures such as vascular intervention requiring large amount of contrast media CO 2 could effectively replace nonionic contrast media

  1. Single-centre cohort study of gender influence in coronary CT angiography in patients with a low to intermediate pretest probability of coronary heart disease

    DEFF Research Database (Denmark)

    Nørgaard, Kirsten Schou; Isaksen, Christin; Buhl, Jørgen Selmer

    2015-01-01

    : This is a cohort study that included patients examined between 2010 and 2013. Data were obtained from the Western Denmark Heart Registry. The follow-up ended 11 March 2014. RESULTS: A total of 3541 people (1621 men and 1920 women) were examined by CCTA. The rate of invasive coronary angiography during follow......-up was 28.5% in men versus 18.3% in women (pwomen (pwomen versus men was 0.98 (95% CI 0.85 to 1.13) for invasive coronary angiography and 0.73 (95% CI 0.57 to 0.93) for coronary...... revascularisation. Further adjustment for age and other risk factors did not change these estimates. CONCLUSIONS: Women had a lower CAC score than men and a corresponding lower rate of invasive coronary angiography. The risk of coronary revascularisation was modestly reduced in women, irrespective of CAC. This may...

  2. Prognostic and therapeutic implications of statin and aspirin therapy in individuals with nonobstructive coronary artery disease: Results from the confirm (coronary CT angiography evaluation for clinical outcomes: An international multicenter registry) registry

    NARCIS (Netherlands)

    B.J.W. Chow (Benjamin); G.R. Small (Gary); Y. Yam (Yeung); L. Chen (Li); R. McPherson (Ruth); S. Achenbach (Stephan); M. Al-Mallah (Mouaz); D.S. Berman (Daniel); M.J. Budoff (Matthew J.); F. Cademartiri (Filippo); T.Q. Callister (Tracy); H.-J. Chang (Hyuk-Jae); V.Y. Cheng (Victor Y.); K. Chinnaiyan (Kavitha); R.C. Cury (Ricardo); A. Delago (Augustin); A. Dunning (Allison); G. Feuchtner (Gundrun); M. Hadamitzky (Martin); J. Hausleiter (Jörg); R.P. Karlsberg (Ronald); P.A. Kaufmann (Philipp A.); Y.-J. Kim (Yong-Jin); J. Leipsic (Jonathon); T.M. LaBounty (Troy); F.Y. Lin (Fay); E. Maffei (Erica); G.L. Raff (Gilbert); L.J. Shaw (Leslee J.); T.C. Villines (Todd); J.K. Min (James)

    2015-01-01

    textabstractObjective - We sought to examine the risk of mortality associated with nonobstructive coronary artery disease (CAD) and to determine the impact of baseline statin and aspirin use on mortality. Approach and Results - Coronary computed tomographic angiography permits direct visualization

  3. Detection of pigment epithelial detachment vascularization in age-related macular degeneration using phase-variance OCT angiography.

    Science.gov (United States)

    McClintic, Scott M; Kim, Dae Yu; Fingler, Jeff; Garcia, Susan; Zawadzki, Robert J; Morse, Lawrence S; Park, Susanna S; Fraser, Scott E; Werner, John S; Ruggiero, Jason P; Schwartz, Daniel M

    2015-01-01

    To demonstrate the use of phase-variance optical coherence tomography (PV-OCT) angiography for detection of pigment epithelial detachment (PED) vascularization in age-related macular degeneration (AMD). Patients with PEDs and exudative AMD were evaluated by the Retina Services at the University of California, Davis, and the University of California, San Francisco. Each subject underwent fluorescein angiography and structural optical coherence tomography (OCT). Phase-variance OCT analysis was used to create angiographic images of the retinal and choroidal vasculature. PV-OCT-generated B-scans were superimposed on structural OCT B-scans to allow easy identification of perfused vascular structures. Three patients with vascularized PEDs were imaged with PV-OCT, and each was found to have a vascular signal extending from the choroid into the hyperreflective substance of the PED. Two patients who had no evidence of PED vascularization on fluorescein angiography did not have vascular signals within their PEDs on PV-OCT. Structural OCT and PV-OCT images can be combined to create composite B-scans that offer high-resolution views of the retinal tissue along with dynamic vascular visualization. This technique offers a fast, noninvasive method for detecting vascularization of PEDs in AMD and may aid in the early detection of neovascular disease.

  4. Development of serial magnification angiography and its clinical significance

    International Nuclear Information System (INIS)

    Sasaki, Tsuneo; Matsubara, Kazuhito; Ishiguchi, Tsuneo; Mashita, Shinichi; Kaii, Osamu

    1979-01-01

    In order to apply serial magnification angiography to clinical examinations so easily, a serial cardioangiography apparatus was equipped with a tube having 0.1 mm focal spot and with DRX-431HD diode. A CAT-FK Type catheter bed (Toshiba) was used as a roentgenographic table and a PUCK film changer was used. Thus, serial magnification angiography can be easily used to clinical examinations, and can be set in a usual x-ray photographic studio. Serial magnification angiography was used to examine the cerebral vessels in 6 patients, vessels of the pulmonary circulation in 1 patient, bronchial arteries in 6 patients, the celiac artery in 18 patients, the superior mesenteric artery in 2 patients, inferior mesenteric artery in 2 patients, the renal artery in 2 patients, and the adrenal vein in 7 patients. Owing to this angiography, minute changes in the vessel in the lesion can be observed and fine neovascularity can be detected. Thus, serial magnification angiography makes diagnoses of vascular disorders easier. (Ichikawa, K.)

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  6. Hepatic Artery Angiography and Embolization for Hemobilia Following Laparoscopic Cholecystectomy

    International Nuclear Information System (INIS)

    Nicholson, Tony; Travis, Simon; Ettles, Duncan; Dyet, John; Sedman, Peter; Wedgewood, Kevin; Royston, Christopher

    1999-01-01

    Purpose: The effectiveness of angiography and embolization in diagnosis and treatment were assessed in a cohort of patients presenting with upper gastrointestinal hemorrhage secondary to hepatic artery pseudoaneurysm following laparoscopic cholecystectomy. Methods: Over a 6-year period 1513 laparoscopic cholecystectomies were carried out in our region. Nine of these patients (0.6%) developed significant upper gastrointestinal bleeding, 5-43 days after surgery. All underwent emergency celiac and selective right hepatic artery angiography. All were treated by coil embolization of the right hepatic artery proximal and distal to the bleeding point. Results: Pseudoaneurysms of the hepatic artery adjacent to cholecystectomy clips were demonstrated in all nine patients at selective right hepatic angiography. In three patients celiac axis angiography alone failed to demonstrate the pseudoaneurysm. Embolization controlled hemorrhage in all patients with no further bleeding and no further intervention. One patient developed a candidal liver abscess in the post-procedure period. All patients are alive and well at follow-up. Conclusion: Selective right hepatic angiography is vital in the diagnosis of upper gastrointestinal hemorrhage following laparoscopic cholecystectomy. Embolization offers the advantage of minimally invasive treatment in unstable patients, does not disrupt recent biliary reconstruction, allows distal as well as proximal control of the hepatic artery, and is an effective treatment for this potentially life-threatening complication

  7. Uterine artery embolization angiography and fertility related aspects

    Directory of Open Access Journals (Sweden)

    Irina A. Horhoianu

    2016-05-01

    Full Text Available Purpose. Uterine artery embolization is a minimally invasive technique. It applies the principle of targeted anatomical structure devascularisation with utility in fibroid conservative therapy, including for future fertility preserving status. The objective of our paper represents a description and evaluation of angiography utility as a predictive method for fertility maintenance. Material and Methods. The angiography and ultrasound aspects obtained from a prospective study in which selected patients have undergone uterine artery embolization for fertility preservation are detailed. Results. The following angiography aspects have been detected: left- right shunt and utero-ovarian collaterals; these have been compared with the ultrasound aspects related to the fibroid evolution form a volumetric and Doppler ultrasound point of view. The angiographical description predicts the impact on post embolization fibroid evolution and upon fertility. An analysis is made in order to assess the way in which angiography can contribute to fertility alteration. Conclusions. The angiography aspects during embolization and the following ultrasound aspects can represent predictive factors as to fertility evolution after uterine artery embolization.

  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. Optimization of Regularization Parameters in Compressed Sensing of Magnetic Resonance Angiography: Can Statistical Image Metrics Mimic Radiologists' Perception?

    OpenAIRE

    Akasaka, Thai; Fujimoto, Koji; Yamamoto, Takayuki; Okada, Tomohisa; Fushumi, Yasutaka; Yamamoto, Akira; Tanaka, Toshiyuki; Togashi, Kaori

    2016-01-01

    In Compressed Sensing (CS) of MRI, optimization of the regularization parameters is not a trivial task. We aimed to establish a method that could determine the optimal weights for regularization parameters in CS of time-of-flight MR angiography (TOF-MRA) by comparing various image metrics with radiologists' visual evaluation. TOF-MRA of a healthy volunteer was scanned using a 3T-MR system. Images were reconstructed by CS from retrospectively under-sampled data by varying the weights for the L...

  10. CT angiography versus intraarterial DSA in abdominal aortic aneurysms; CT-Angiographie versus intraarterielle DSA bei Bauchaortenaneurysmen

    Energy Technology Data Exchange (ETDEWEB)

    Rieker, O. [Klinik fuer Radiologie, Johannes-Gutenberg-Universitaet, Mainz (Germany); Dueber, C. [Klinik fuer Radiologie, Johannes-Gutenberg-Universitaet, Mainz (Germany); Schmiedt, W. [Klinik fuer Herz-, Thorax- und Gefaesschirurgie, Johannes-Gutenberg-Universitaet, Mainz (Germany); Neufang, A. [Klinik fuer Herz-, Thorax- und Gefaesschirurgie, Johannes-Gutenberg-Universitaet, Mainz (Germany); Pittow, M. [Klinik fuer Radiologie, Johannes-Gutenberg-Universitaet, Mainz (Germany); Schweden, F. [Klinik fuer Radiologie, Johannes-Gutenberg-Universitaet, Mainz (Germany)

    1996-07-01

    To evaluate if CT angiography is able to image all features necessary for the preoperative planning of abdominal aortic aneurysms (accessory renal arteries, stenoses or occlusions of renal and iliac arteries, patency of inferior mesentric artery). CT angiography and DSA were performed on 27 patients with abdominal aortic aneurysms. CT angiography was performed using a protocol that covered the abdominal aorta and the pelvic arteries with a single spiral acquisition (contrast dose: 150 ml, collimation: 5 mm, table feed: 7.5 mm/s, increment of reconstruction: 2 mm). Maximum intensity projections (MIP) and axial scans were compared with the results of intraarterial DSA. Using axial scans and subvolume MIP, CTA accurately defined 7/8 accessory renal arteries, 13/13 occlusions and 9/12 high grade stenoses of renal and pelvic arteries. High-grade stenoses of the iliac arteries were underestimated in two cases and overlooked in one case. CT angiography was superior to DSA in imaging the inferior mesenteric artery. CT angiography precisely diagnosed 33 aneurysms of the iliac, renal and coeliac arteries. CT angiography using a single administration of intravenous contrast may replace preoperative DSA in most cases of abdominal aortic aneurysm. (orig.) [Deutsch] Ziel dieser Studie war es zu pruefen, ob mit der CT-Angiographie die fuer die praeoperative Planung von Bauchaortenaneurysmen relevanten Gefaessveraenderungen darstelbar sind (Akzessorische Nierenarterien, Nierenarterienstenosen, A. mesenterica inferior, Beckenarterien). Die CT-Angiographien wurden mit einem Protokoll durchgefuehrt, das die Bauchaorta und die Beckenarterien bis zur Leiste mit einer einzigen Spiralakquisition erfasst (150 ml Kontrastmittel, Kollimation: 5 mm, Tischvorschub: 7,5 mm/s, Rekonstruktionsintervall: 2 mm). Die Befunde aus Maximum-Intensitaets-Projektionen (MIP) und den axialen Schnittbildern wurden mit den Befunden der intraarteriellen DSA bei 27 Patienten verglichen. Bei Hinzuziehung von

  11. Upper extremity computed tomographic angiography: state of the art technique and applications in 2010.

    Science.gov (United States)

    Hellinger, Jeffrey C; Epelman, Monica; Rubin, Geoffrey D

    2010-03-01

    From technical and interpretative perspectives, upper extremity computed tomographic angiography (CTA) is one of the more challenging vascular CTA applications. Synchronizing the relatively large scan coverage with a single bolus of contrast medium requires precise selection of acquisition and contrast delivery parameters. To avoid multiple acquisitions and minimize radiation exposure and contrast medium volume, it is important to have fundamental knowledge on how to select these parameters. Equally important is knowing how to adeptly apply advanced workstation visualization techniques and tool functions for the upper extremity vascular tree. In this review, upper extremity arterial and venous anatomy is discussed, followed by a detailed overview on state-of-the-art upper extremity CTA technical considerations and strategies. The review concludes with discussion and illustration of upper extremity CTA clinical applications. Copyright 2010 Elsevier Inc. All rights reserved.

  12. MR inflow angiography for the evaluation of dural sinus patency

    International Nuclear Information System (INIS)

    Poncelet, B.; Baleriaux, D.; Grand, C.; Van Dijk, P.; De Graaf, R.; Segebarth, C.

    1990-01-01

    This paper assesses dural sinus patency with two-dimensional inflow MR angiography. Twelve patients with potential dural sinus (superior sagittal and transverse sinus) involvement related to tumors of the falx or the convexity (meningiomas, metastasis) were examined with digital subtraction angiography (DSA), Mr imaging (1.5-T Gyroscan system), including T1-weighted (pre- and post-agadolinium) and T2-weighted spin-echo imaging, and MR angiography. For the MR angiographic study, a gradient-echo fast field echo sequence with flow compensation was used. Thin (2-mm), contiguous coronal or transverse sections were acquired sequentially. Three-dimensional reconstruction with MIP processing was then performed. CT, DSA, and MR imaging were performed for presurgical evaluation. Surgical confirmation of sinus patency was obtained for all patients

  13. Nosocomial septicemia and therapeutic angiography. Report of four cases

    International Nuclear Information System (INIS)

    Meyer, Ph.; Reizine, D.; Merland, J.J.; Guerin, J.M.

    1988-01-01

    Therapeutic angiography may be responsible for rare, but serious infectious complications.The authors report 4 cases occurring immediately following angiography. Three modes of contamination are proposed. Contamination by material used during the angiography is due to multiresistant hospital organisms. Penetration of cutaneous organisms into the circulation from the puncture site and bacterial contamination of a focus of tissue necrosis distal to the embolisation explain the other cases. Curative treatment is difficult because of the possibility of contamination of the embolisation material. Prophylactic treatment is essential and consists of respect of the rules of surgical asepsis, bacteriological control of the fluids used and eradication of adjacent septic foci. Routine antibiotic prophylaxis has yet to be evaluated [fr

  14. MR angiography as a screening tool for intracranial aneurysms: feasibility, test characteristics, and interobserver agreement

    NARCIS (Netherlands)

    Raaymakers, T. W.; Buys, P. C.; Verbeeten, B.; Ramos, L. M.; Witkamp, T. D.; Hulsmans, F. J.; Mali, W. P.; Algra, A.; Bonsel, G. J.; Bossuyt, P. M.; Vonk, C. M.; Buskens, E.; Limburg, M.; van Gijn, J.; Gorissen, A.; Greebe, P.; Albrecht, K. W.; Tulleken, C. A.; Rinkel, G. J.

    1999-01-01

    OBJECTIVE: MR angiography may be an appropriate tool to screen for unruptured intracranial aneurysms. Feasibility, test characteristics, and interobserver agreement in evaluation of MR angiograms were assessed by members of the MARS (Magnetic resonance Angiography in Relatives of patients with

  15. 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

  16. Optimization of Ecg G