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Sample records for resonance angiography study

  1. Gadolinium-enhanced magnetic resonance angiography for pulmonary embolism: a multicenter prospective study (PIOPED III).

    Science.gov (United States)

    Stein, Paul D; Chenevert, Thomas L; Fowler, Sarah E; Goodman, Lawrence R; Gottschalk, Alexander; Hales, Charles A; Hull, Russell D; Jablonski, Kathleen A; Leeper, Kenneth V; Naidich, David P; Sak, Daniel J; Sostman, H Dirk; Tapson, Victor F; Weg, John G; Woodard, Pamela K

    2010-04-06

    The accuracy of gadolinium-enhanced magnetic resonance pulmonary angiography and magnetic resonance venography for diagnosing pulmonary embolism has not been determined conclusively. To investigate performance characteristics of magnetic resonance angiography, with or without magnetic resonance venography, for diagnosing pulmonary embolism. Prospective, multicenter study from 10 April 2006 to 30 September 2008. 7 hospitals and their emergency services. 371 adults with diagnosed or excluded pulmonary embolism. Sensitivity, specificity, and likelihood ratios were measured by comparing independently read magnetic resonance imaging with the reference standard for diagnosing pulmonary embolism. Reference standard diagnosis or exclusion was made by using various tests, including computed tomographic angiography and venography, ventilation-perfusion lung scan, venous ultrasonography, d-dimer assay, and clinical assessment. Magnetic resonance angiography, averaged across centers, was technically inadequate in 25% of patients (92 of 371). The proportion of technically inadequate images ranged from 11% to 52% at various centers. Including patients with technically inadequate images, magnetic resonance angiography identified 57% (59 of 104) with pulmonary embolism. Technically adequate magnetic resonance angiography had a sensitivity of 78% and a specificity of 99%. Technically adequate magnetic resonance angiography and venography had a sensitivity of 92% and a specificity of 96%, but 52% of patients (194 of 370) had technically inadequate results. A high proportion of patients with suspected embolism was not eligible or declined to participate. Magnetic resonance pulmonary angiography should be considered only at centers that routinely perform it well and only for patients for whom standard tests are contraindicated. Magnetic resonance pulmonary angiography and magnetic resonance venography combined have a higher sensitivity than magnetic resonance pulmonary angiography

  2. Hemifacial spasm. Study by magnetic resonance angiography; Espasmo hemifacial: estudo pela angiografia por ressonancia magnetica

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    Bittar, Miriam Salvadori; Staut, Claudio Cesar Vilela; Barbosa, Egberto Reis; Bacheschi, Luiz Alberto; Magalhaes, Alvaro Cebrian de Almeida [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina. Hospital das Clinicas

    1995-12-31

    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) 29 refs., 2 figs., 2 tabs.

  3. Magnetic resonance angiography

    Science.gov (United States)

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

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

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    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.

  5. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... I-131 Therapy Radiology and You 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 ...

  6. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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

  7. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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

  8. Gadofosveset trisodium-enhanced magnetic resonance angiography of the left atrium-A feasibility study

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    Wagner, Moritz, E-mail: moritz.wagner@charite.d [Department of Radiology, Charite - University Hospital, Berlin (Germany); Rief, Matthias; Asbach, Patrick [Department of Radiology, Charite - University Hospital, Berlin (Germany); Vogtmann, Thomas [Department of Cardioloy and Angiology, Charite - University Hospital, Berlin (Germany); Huppertz, Alexander [Imaging Science Institute Charite Berlin, Berlin (Germany); Beling, Mark [Department of Cardioloy and Angiology, Charite - University Hospital, Berlin (Germany); Butler, Craig [Mazankowski Alberta Heart Institute, University of Alberta, Edmonton (Canada); Laule, Michael [Department of Cardioloy and Angiology, Charite - University Hospital, Berlin (Germany); Warmuth, Carsten; Taupitz, Matthias; Hamm, Bernd; Lembcke, Alexander [Department of Radiology, Charite - University Hospital, Berlin (Germany)

    2010-08-15

    Aim: Imaging of the left atrium is regularly performed prior to pulmonary vein isolation. The aim of the study was to evaluate the feasibility of contrast-enhanced high-resolution magnetic resonance angiography (MRA) of the left atrium using the blood-pool contrast agent gadofosveset trisodium in comparison to noncontrast MRA. Materials and methods: Twenty consecutive patients were examined by free-breathing electrocardiogram-gated whole-heart MRA (reconstructed spatial resolution, 0.7 mm x 0.6 mm x 0.8 mm) with a noncontrast T2-prepared steady state free precession sequence (T2-prep SSFP) and a gadofosveset trisodium-enhanced inversion-recovery SSFP sequence (CE IR-SSFP). Contrast-to-noise ratio (CNR) of blood in the left atrium was determined. Depiction of the left atrium was rated by two radiologists in consensus. A cardiologist segmented the MR data sets and rated depiction of the left atrium. Results: Five of 20 patients had irregular breathing patterns with navigator efficiency less than 35% and were excluded from evaluation. CNR was significantly higher for CE IR-SSFP compared with T2-prep SSFP (18.4 {+-} 5.3 vs. 11.7 {+-} 3.5, p < 0.01). Depiction of the left atrium by T2-prep SSFP was rated as good in four patients, moderate in ten patients, and poor in one patient, whereas depiction of the left atrium by CE IR-SSFP was rated as excellent in nine patients, good in four patients, and moderate in two patients. CE IR-SSFP allowed for semiautomated segmentation of the left atrium in 15 patients, whereas T2-prep SSFP allowed for segmentation only in ten patients. Conclusion: Gadofosveset trisodium-enhanced MRA of the left atrium is feasible with significantly improved image quality compared to noncontrast MRA.

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

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

    2004-02-01

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

  10. 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.

  11. Magnetic resonance angiography in suspected cerebral vasculitis

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    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.)

  12. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Therapy November 8 is the International Day of Radiology (IDoR) Radiology and You Sponsored by Image/Video Gallery Your ... Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot org Hello, I’m Dr. Elliot ...

  13. Magnetic Resonance Angiography: Principles and Applications.

    Science.gov (United States)

    Dyke, Lara M

    2013-12-01

    Magnetic Resonance Angiography: Principles and Applications. Carr J. C., Carroll T. J., Springer-Verlag, Heidelberg/New York, 2012. 412 pp. Price $179.00. ISBN 978-1-4419-1685-3 (hardcover). © 2013 American Association of Physicists in Medicine.

  14. A prospective feasibility study of duplex ultrasound arterial mapping, digital-subtraction angiography, and magnetic resonance angiography in management of critical lower limb ischemia by endovascular revascularization.

    Science.gov (United States)

    Lowery, A J; Hynes, N; Manning, B J; Mahendran, M; Tawfik, S; Sultan, S

    2007-07-01

    Duplex ultrasound arterial mapping (DUAM) allows precise evaluation of peripheral vascular disease (PVD). However, magnetic resonance angiography (MRA) and digital-subtraction angiography (DSA) are the diagnostic tools used most frequently prior to intervention. Our aim was to compare clinical pragmatism, hemodynamic outcomes, and cost-effectiveness when using DUAM alone compared to DSA or MRA as preoperative assessment tools for endovascular revascularization (EvR) in critical lower limb ischemia (CLI). From 2002 through 2005, 465 patients were referred with PVD. Of these, 199 had CLI and 137 required EvR. Preoperative diagnostic evaluation included DUAM (n = 41), DSA (n = 50), or MRA (n = 46). EvR was aortoiliac in 27% of cases and infrainguinal in 73%. Patients were assessed at day 1, 6 weeks, 3 months, and 6 months. Composite end points were relief of rest pain, ulcer/gangrene healing, and increase in perfusion pressure, as measured by ankle-brachial index (ABI) and digital pressures. Patency by DUAM, limb salvage, morbidity, mortality, length of stay, and cost-effectiveness were compared between groups using nonparametric t-test, analysis of variance, and Kaplan-Meier analysis. The three groups were comparable in terms of age, sex, comorbidity, and Society for Vascular Surgery/International Society of Cardiovascular Surgery clinical classification. Six-month mean improvement in ABI in the DUAM group was comparable to that in the DSA group (P = 0.25) and significantly better than that in the MRA group (P < 0.05). Six-month patency rates for the DUAM group were comparable to those in the DSA group (P = 0.68, relative risk [RR] = 0.74, 95% confidence interval [CI] 0.18-2.99) and superior to that in the MRA group (P = 0.022, RR = 0.255, 95% CI 0.09-0.71). Length of hospital stay was lower in the DUAM group compared with the DSA group (P < 0.0001) and the MRA group (P = 0.0003). The cost of DUAM is lower than that of both DSA and MRA. DUAM accurately identified the

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

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

    1996-07-01

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

  16. Analysis of enlarged images using time-of-flight magnetic resonance angiography, computed tomography, and conventional angiography.

    Science.gov (United States)

    Heo, Yeong-Cheol; Lee, Hae-Kag; Yang, Han-Jun; Cho, Jae-Hwan

    2014-12-01

    This study aimed to assess the accuracy of time-of-flight magnetic resonance angiography, computed tomography, and conventional angiography in depicting the actual length of the blood vessels. Three-dimensional time-of-flight magnetic resonance angiography and computed tomography angiography were performed using a flow phantom model that was 2.11 mm in diameter and had a total area of 0.26 cm(2). After this, volume rendering technique and the maximum intensity projection method as well as two-dimensional digital subtraction angiography and three-dimensional rotational angiography based on conventional angiography were conducted. For three-dimensional time-of-flight magnetic resonance angiography, 8 channel sensitivity encoding (SENSE) head coil for the 3.0 Tesla equipment was used. Fluid was added to the normal saline solution at various rates, such as 11.4, 20.0, 31.4, 40.0, 51.5, 60.0, 71.5, 80.1, 91.5, and 100.1 cm/s using an automatic contrast media injector. Each image was thoroughly examined. After reconstructing the image using the maximum intensity projection method, the length of the conduit in the center of the coronal plane was measured 30 times. After performing computed tomography angiography with the 64-channel CT scanner and 16-channel CT scanner, the images were sent to TeraRecon. Then, the length of the conduit in the center of the coronal plane of each image was measured 30 times after reconstructing the images using volume rendering and maximum intensity projection techniques. For conventional angiography, three-dimensional rotational angiography and two-dimensional digital subtraction angiography were used. Images obtained by three-dimensional rotational angiography were reconstructed and enhanced by 33, 50, and 100 % in the 128 Matrix and the 256 Matrix, respectively on the Xtra Vision workstation. The maximum intensity projection was used for the reconstruction, and the length of the conduit was measured 30 times in the center of the coronal

  17. The study of vascular dynamics for the effect of a compress pack on pain relief using magnetic resonance angiography

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    Baek, Ji Won; Lim, Young Khi [Gachon University, Sungnam (Korea, Republic of)

    2015-12-15

    This study was to investigate the effects of the hot compress pack on alleviating local muscular discomfort, stiffness in limbs as well as the chronic pains such as migraine in terms of hemodynamics. In this study, the hot compress band was put on the neck and the local physiological change on the stimulation site and the cranial blood circulation change were examined. We recruited healthy volunteers (n=8, mean age: 32.13 (4.61)), who participated in the magnetic resonance imaging (MRI) study. Local skin color and temperature were measured for the local effect of the hot compress band and the changes of intra-cranial and extra-cranial blood vessels were examined with MR angiography (MRA) images. The skin temperature increased from 36.4 degrees Celsius at the rest condition to 36.7 degrees Celsius and 37.1 degrees Celsius after 15 min and 30 min stimulation, respectively. The change of the extra-cranial blood vessels between pre-stimulation and post-stimulation of 30 min was significantly increased (+38.8%), while the change of the intra-cranial blood vessels was negligible. In this study, we demonstrated that the hot compress band on the neck yielded the increase of local skin temperature on the stimulation site and it made an effect on the extracranial circulation. In conclusion, the stimulation with a hot compress could facilitate the blood circulation, causing to relieve the muscular discomfort, stiffness in limbs as well as the chronic pains such as migraine.

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

    OpenAIRE

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

    2015-01-01

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

  19. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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  20. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... CT Angiography Video: Myelography Video: CT of the Heart Video: Radioiodine I-131 Therapy Radiology and You ... CT Angiography Video: Myelography Video: CT of the Heart Video: Radioiodine I-131 Therapy Radiology and You ...

  1. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... is National Breast Cancer Awareness Month Recently posted: Medical Imaging Costs Magnetoencephalography (MEG) Video: Coronary CT Angiography ... home. Tell the radiologic technologist if you have medical devices implanted in your body as these can ...

  2. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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  3. Evaluation of the lower limb vasculature before free fibula flap transfer. A prospective blinded comparison between magnetic resonance angiography and digital subtraction angiography

    NARCIS (Netherlands)

    Klein, Steven; Van Lienden, Krijn P; Van't Veer, Marcel; Smit, Jeroen M; Werker, Paul M N

    2013-01-01

    Introduction The aim of this study was to compare magnetic resonance angiography (MRA) with digital subtraction angiography (DSA) in the preoperative assessment of crural arteries and their skin perforators prior to free fibular transfer. Patients and methods Fifteen consecutive patients, scheduled

  4. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Index A-Z Spotlight October is National Breast Cancer Awareness Month Recently posted: Medical Imaging Costs Magnetoencephalography (MEG) Video: Coronary CT Angiography Video: Myelography Video: CT of the Heart Video: Radioiodine I-131 Therapy November 8 is the International Day of Radiology ( ...

  5. A comparison between magnetic resonance angiography at 3 teslas (time-of-flight and contrast-enhanced and flat-panel digital subtraction angiography in the assessment of embolized brain aneurysms

    Directory of Open Access Journals (Sweden)

    Guilherme S. Nakiri

    2011-01-01

    Full Text Available PURPOSE: To compare the time-of-flight and contrast-enhanced- magnetic resonance angiography techniques in a 3 Tesla magnetic resonance unit with digital subtraction angiography with the latest flat-panel technology and 3D reconstruction in the evaluation of embolized cerebral aneurysms. INTRODUCTION: Many embolized aneurysms are subject to a recurrence of intra-aneurismal filling. Traditionally, imaging surveillance of coiled aneurysms has consisted of repeated digital subtraction angiography. However, this method has a small but significant risk of neurological complications, and many authors have advocated the use of noninvasive imaging methods for the surveillance of embolized aneurysms. METHODS: Forty-three aneurysms in 30 patients were studied consecutively between November 2009 and May 2010. Two interventional neuroradiologists rated the time-of-flight-magnetic resonance angiography, the contrast-enhanced-magnetic resonance angiography, and finally the digital subtraction angiography, first independently and then in consensus. The status of aneurysm occlusion was assessed according to the Raymond scale, which indicates the level of recanalization according to degrees: Class 1: excluded aneurysm; Class 2: persistence of a residual neck; Class 3: persistence of a residual aneurysm. The agreement among the analyses was assessed by applying the Kappa statistic. RESULTS: Inter-observer agreement was excellent for both methods (K = 0.93; 95 % CI: 0.84-1. Inter-technical agreement was almost perfect between time-of-flight-magnetic resonance angiography and digital subtraction angiography (K = 0.98; 95 % CI: 0.93-1 and between time-of-flight-magnetic resonance angiography and contrast-enhanced-magnetic resonance angiography (K = 0.98; 95% CI: 0.93-1. Disagreement occurred in only one case (2.3%, which was classified as Class I by time-of-flight-magnetic resonance angiography and Class II by digital subtraction angiography. The agreement between

  6. APPLICATION OF MAGNETIC RESONANCE ANGIOGRAPHY IN PORTAL HYPERTENSIVE SURGERY

    Institute of Scientific and Technical Information of China (English)

    LIU Hua; CHEN Zhi-ping; WU Zhi-yong

    2005-01-01

    Objective To compare magnetic resonance angiography (MRA) with traditional angiography and doppler ultrasonography (DUS) in the assessment of portal venous anatomy and its hemodynamics. MethodsThree dimensional dynamic contrast-enhanced (3D-DCE) MRA and two dimensional phase-contrast (2D-PC) MR were used for the study of portal venous system in the patients with portal hypertension and those without liver cirrhosis. The comparison of the portal blood flow (PBF) measured with 2D-PC MR and DUS was made. ResultsThe portal vein, splenic vein, superior mesenteric vein, cephalic collateral veins and anastomotic stoma of surgical shunting were clearly displayed in 3D-DCE MRA. There was no significant difference between PBF measured with 2D-PC MR and DUS. Conclusion The results of present study indicate that the anatomical imaging of the portal venous system can be clearly revealed in MRA and the PBF can be accurately measured with 2D-PC MR. It is believed that MRA is a useful tool in the management of the patients with portal hypertension.

  7. Unenhanced respiratory-navigated NATIVE(®) TrueFISP magnetic resonance angiography in the evaluation of renal arteries: Comparison with contrast-enhanced magnetic resonance angiography.

    Science.gov (United States)

    Değirmenci, B; Kara, M; Kıdır, V; İnal, S; Sezer, T; Umul, A; Orhan, H; Çelik, A O; Demirtaş, H; Yilmaz, Ö

    2017-02-01

    To compare unenhanced three-dimensional (3D) NATIVE(®) true fast imaging with steady-state precession (TrueFISP) magnetic resonance (MR) angiography with the more conventional MR angiography technique obtained after intravenous administration of a gadolinium chelate in the evaluation of renal arteries and their branches in patients with suspected renal artery stenosis. A total of 39 patients (25 men, 14 women) with a mean age of 51.4±17.5years (SD) (range: 10-82years) were included in the study. All patients with suspected renal artery stenosis underwent unenhanced 3D NATIVE(®) TrueFISP MR angiography and contrast-enhanced MR angiography. The two MR angiography methods were compared by two independent readers for image quality using a four-point scale, diagnostic performance and grading of renal artery stenosis on a total of 78 renal arteries. For both readers image quality of unenhanced 3D NATIVE(®) TrueFISP MR angiography (3.12 to 3.63) was greater than that of contrast-enhanced MR angiography (1.94 to 2.71) for renal artery ostium-trunk and the left renal artery segmental branches. The sensitivity of 3D NATIVE(®) TrueFISP MR angiography for the diagnosis of renal artery stenosis was 100% for both readers for the right renal artery and 66% and 80% for the left renal artery for reader 1 and reader 2, respectively. Agreement between 3D NATIVE(®) TrueFISP MR angiography and CE-MR angiography was 95% (74/78) for reader 1 and 92% (72/78) for reader 2. Unenhanced NATIVE(®) TrueFISP magnetic resonance angiography can play an additional role in the evaluation of renal arteries in patients with hypertension, especially in subjects at risk of nephrogenic systemic fibrosis. Copyright © 2016 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

  8. Fluorine-19 magnetic resonance angiography of the mouse.

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    Ruud B van Heeswijk

    Full Text Available PURPOSE: To implement and characterize a fluorine-19 ((19F magnetic resonance imaging (MRI technique and to test the hypothesis that the (19F MRI signal in steady state after intravenous injection of a perfluoro-15-crown-5 ether (PCE emulsion may be exploited for angiography in a pre-clinical in vivo animal study. MATERIALS AND METHODS: In vitro at 9.4T, the detection limit of the PCE emulsion at a scan time of 10 min/slice was determined, after which the T(1 and T(2 of PCE in venous blood were measured. Permission from the local animal use committee was obtained for all animal experiments. 12 µl/g of PCE emulsion was intravenously injected in 11 mice. Gradient echo (1H and (19F images were obtained at identical anatomical levels. Signal-to-noise (SNR and contrast-to-noise (CNR ratios were determined for 33 vessels in both the (19F and (1H images, which was followed by vessel tracking to determine the vessel conspicuity for both modalities. RESULTS: In vitro, the detection limit was ∼400 µM, while the (19F T(1 and T(2 were 1350±40 and 25±2 ms. The (19F MR angiograms selectively visualized the vasculature (and the liver parenchyma over time while precisely coregistering with the (1H images. Due to the lower SNR of (19F compared to (1H (17±8 vs. 83±49, p<0.001, the (19F CNR was also lower at 15±8 vs. 52±35 (p<0.001. Vessel tracking demonstrated a significantly higher vessel sharpness in the (19F images (66±11 vs. 56±12, p = 0.002. CONCLUSION: (19F magnetic resonance angiography of intravenously administered perfluorocarbon emulsions is feasible for a selective and exclusive visualization of the vasculature in vivo.

  9. Diagnostic value of 3D contrast-enhanced magnetic resonance angiography in Takayasu's arteritis - a comparative study with digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Garg, Shobhit K.; Kumar, Sunil [Sanjay Gandhi Postgraduate Institute of Medical Sciences, Department of Radiodiagnosis, Lucknow, UP (India); Mohan, Suyash [Sanjay Gandhi Postgraduate Institute of Medical Sciences, Department of Radiodiagnosis, Lucknow, UP (India); University of Pennsylvania Health System, Neuroradiology Division, Department of Radiology, Philadelphia, PA (United States)

    2011-08-15

    To assess the diagnostic value of 3D CEMRA in TA compared with DSA. Twenty-two patients with clinically suspected TA based on 1990 ACR criteria for the classification of TA, were included in this study. There were 16 female and 6 male patients with ages ranging from 11 to 50 years (mean age 25 years). CEMRA and DSA were performed in all patients within 4 weeks of each other, for detection of stenosis, occlusion and aneurysm in the arch vessels, renal arteries and aortic segments. (1) TA was confirmed by CEMRA in all patients. (2) 147 arteries did not reveal any steno-occlusive lesion on CEMRA compared with 158 on DSA. (3) 75 stenoses, (excluding occlusions) were detected on CEMRA compared with DSA, which revealed 65 stenotic lesions, with sensitivity, specificity, PPV, NPV and DA for detection of a significant (>50%) stenotic lesion being 98.33%, 97.25%, 92.18%, 99.43% and 97.52% respectively. (4) Aneurysmal dilatation was detected in 13 arteries on CEMRA compared with 16 on DSA. Diagnostic value of CEMRA is comparable to that of DSA with a very strong and statistically significant correlation between DSA and CEMRA in detection and grading of characteristic steno-occlusive lesions of TA. (orig.)

  10. A multi-center, comparative, phase 3 study to determine the efficacy of gadofosveset-enhanced magnetic resonance angiography for evaluation of renal artery disease

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Robert [St. Boniface General Hospital, Winnipeg, Manitoba (Canada); Vymazal, Josef [Hospital Na Homolce, Prague (Czech Republic); Martinez-Lopez, Manuel [Hospital Medica Sur, Mexico City (Mexico); Neuwirth, Jiri [Faculty Hospital Motol, Prague (Czech Republic); Salgado, Perla [American British Cowdray Medical Center, Mexico City (Mexico); Beregi, Jean-Paul [Hopital Cardiologique, Lille (France); Peduto, Anthony [Westmead Hospital, Westmead New South Wales (Australia); Pena-Almaguer, Erasmo de la [Christus-Muguerza Medical Center, Monterrey, Nuevo Leon (Mexico); Slater, Greg J. [Greenslopes Private Hospital, Greenslopes, Queensland (Australia); Shamsi, Kohkan [Berlex Laboratories, Montville, NJ (United States); Parsons, Edward C. [EPIX Pharmaceuticals, Inc., Lexington, MA (United States)], E-mail: eparsons@epixpharma.com

    2008-02-15

    Purpose: To determine prospectively the safety and efficacy of the blood-pool contrast agent gadofosveset trisodium in renal artery magnetic resonance angiography (MRA). Materials and methods: Gadofosveset (0.03 mmol/kg) was administered to adult patients with known or suspected renal arterial disease in a multi-center phase 3 single dose study. The drug binds reversibly to albumin, prolonging the blood residence time, and allowing collection of images in the first-pass and steady-state phases. The combination of these images was compared to non-contrast MRA, using catheter X-ray angiography (XRA) as the standard of reference (SOR). All MRA images were collected at 1.5 T in one imaging session for direct comparison, and XRA within 30 days. Sensitivity, specificity, and accuracy for diagnosing significant disease (stenosis {>=}50%) were calculated for MRA using three independent blinded readers. Patient safety was monitored for 72-96 h. Results: A total of 145 patients at 18 centers were enrolled and received gadofosveset; the 127 with complete efficacy data entered the primary efficacy analysis. Gadofosveset-enhanced MRA led to significant improvement (p < 0.01) in sensitivity (+25%, +26%, +42%), specificity (+23%, +25%, +29%), and accuracy (+23%, +28%, +29%) over non-enhanced MRA for the three readers. The rate of uninterpretable examinations decreased from 30% to less than 2%. There were no serious adverse events, and the most common adverse events were nausea, pruritis, and headache (8% each). No significant trends in clinical chemistry parameters, nor significant changes in serum creatinine, were found following administration of gadofosveset. Conclusion: In patients with known or suspected renal arterial disease, multi-phase gadofosveset-enhanced MRA significantly improves sensitivity, specificity, and accuracy versus non-enhanced MRA. Gadofosveset was safe and well tolerated in this patient population.

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

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

    1999-06-01

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

  12. Thyroid Nodules Detected by Contrast-Enhanced Magnetic Resonance Angiography: Prevalence and Clinical Significance.

    Science.gov (United States)

    Lim, Hyun Kyung; Park, Sung Tae; Ha, Hongil; Choi, Seo-youn

    2016-01-01

    Incidental thyroid lesions are frequently found on contrast-enhanced magnetic resonance (CE-MR) angiography. The purpose of this study is to determine the prevalence of thyroid incidentalomas detected by CE-MR angiography and to evaluate their clinical significance by correlation with ultrasound (US) and cytopathological results. We retrospectively reviewed 3,299 consecutive CE-MR angiography examinations performed at our institution between January 2010 and March 2013. Two radiologists evaluated the CE-MR angiography imaging in consensus regarding the presence, location, and vascularity of thyroid incidentaloma. We correlated these findings with follow-up US and cytopathologic results. The prevalence of thyroid incidentalomas detected by CE-MR angiography was 4.6% (152/3,299 patients). CE-MR angiography showed hypervascularity in 86.8% (145/167), isovascularity in 8.4% (14/167), and hypovascularity in 4.8% (8/167) of thyroid nodules compared to vascularity of thyroid parenchyma. Among the patients with thyroid incidentaloma, 34 patients (22.4%) were followed by US examination, and all 36 nodules on CE-MR angiography were detected on follow-up US. Of these nodules, 9 (25%) nodules were classified as probably benign, 26 (72.2%) as indeterminate, and 1 (2.8%) as suspicious malignant nodule. Among the 16 nodules with available cytopathologic results, 12 nodules were benign, 2 nodules were follicular neoplasm, and 2 nodules showed non-diagnostic results. Incidental thyroid nodules were found in 4.6% of CE-MR angiography examinations. Because the high incidence of indeterminate US feature among thyroid incidentaloma, when a thyroid incidentaloma is detected on CE-MR angiography, further evaluation with US should be performed.

  13. Thyroid Nodules Detected by Contrast-Enhanced Magnetic Resonance Angiography: Prevalence and Clinical Significance.

    Directory of Open Access Journals (Sweden)

    Hyun Kyung Lim

    Full Text Available Incidental thyroid lesions are frequently found on contrast-enhanced magnetic resonance (CE-MR angiography. The purpose of this study is to determine the prevalence of thyroid incidentalomas detected by CE-MR angiography and to evaluate their clinical significance by correlation with ultrasound (US and cytopathological results.We retrospectively reviewed 3,299 consecutive CE-MR angiography examinations performed at our institution between January 2010 and March 2013. Two radiologists evaluated the CE-MR angiography imaging in consensus regarding the presence, location, and vascularity of thyroid incidentaloma. We correlated these findings with follow-up US and cytopathologic results.The prevalence of thyroid incidentalomas detected by CE-MR angiography was 4.6% (152/3,299 patients. CE-MR angiography showed hypervascularity in 86.8% (145/167, isovascularity in 8.4% (14/167, and hypovascularity in 4.8% (8/167 of thyroid nodules compared to vascularity of thyroid parenchyma. Among the patients with thyroid incidentaloma, 34 patients (22.4% were followed by US examination, and all 36 nodules on CE-MR angiography were detected on follow-up US. Of these nodules, 9 (25% nodules were classified as probably benign, 26 (72.2% as indeterminate, and 1 (2.8% as suspicious malignant nodule. Among the 16 nodules with available cytopathologic results, 12 nodules were benign, 2 nodules were follicular neoplasm, and 2 nodules showed non-diagnostic results.Incidental thyroid nodules were found in 4.6% of CE-MR angiography examinations. Because the high incidence of indeterminate US feature among thyroid incidentaloma, when a thyroid incidentaloma is detected on CE-MR angiography, further evaluation with US should be performed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Yumin; Zhu, Ming; Sun, Aimin; Li, Yuhua [Shanghai Jiao Tong University School of Medicine, Department of Radiology, Shanghai Children' s Medical Center, Shanghai (China); Jaffe, Richard B. [Primary Children' s Medical Center, Department of Medical Imaging, Salt Lake City, UT (United States); Gao, Wei [Shanghai Jiao Tong University School of Medicine, Department of Cardiology, Shanghai Children' s Medical Center, Shanghai (China)

    2007-03-15

    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.)

  15. Middle cerebral artery variations detected by magnetic resonance angiography

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, A.; Kato, A.; Takase, Y.; Kudo, S. [Saga Medical School, Saga (Japan). Dept. of Radiology

    2000-04-01

    Middle cerebral artery (MCA) variations are found incidentally on cranial magnetic resonance angiography (MRA). Our goal was to examine the incidence and types of MCA variations detected by MRA. Between April 1996 and March 1999, cranial MRA was performed in 432 cases at our institution. Most of the patients examined had or were suspected to have cerebrovascular disease. After excluding 7 patients with moyamoya disease, we retrospectively reviewed 425 MRA results. A 1.5-T scanner was used in all studies, and maximum-intensity projection images obtained using the three-dimensional time-of-flight technique were displayed stereoscopically. In the 425 patients MRA revealed 16 anomalous MCAs, including 9 duplicated MCAs, 5 accessory MCAs, and 2 fenestrated MCAs, which is a rate of 3.8%. Thus, although the clinical significance is not great, we found a relatively high incidence of anomalous MCAs on MRA. We stress that knowledge and recognition of these variations are useful and important during the interpretation of cranial MRA. (orig.)

  16. Association of Lumbar Arterial Stenosis with Low Back Symptoms: A Cross-Sectional Study Using Two-Dimensional Time-of-Flight Magnetic Resonance Angiography

    Energy Technology Data Exchange (ETDEWEB)

    Korkiakoski, A.; Niinimaeki, J.; Karppinen, J.; Korpelainen, R.; Haapea, M.; Natri, A.; Tervonen, O. (Inst. of Clinical Sciences, Dept. of Physical and Rehabilitation Medicine, Univ. of Oulu, Oulu (Finland))

    2009-01-15

    Background: Recent studies indicate that diminished blood flow may cause low back symptoms and intervertebral disc degeneration. Purpose: To explore the association between lumbar arterial stenosis as detected by two-dimensional time-of-flight magnetic resonance angiography (2D TOF-MRA) and lumbar pain symptoms in an occupational cohort of middle-aged Finnish males. Material and Methods: 228 male subjects aged 36 to 55 years (mean 47 years) were imaged with 2D TOF-MRA. Additionally, 20 randomly selected subjects were scanned with contrast-enhanced MRA (ceMRA). In each subject, the first (L1) to fourth (L4) segmental lumbar arteries were evaluated for lumbar artery stenosis using a dichotomic scale. One subject was excluded because of poor image quality, reducing the study population to 227 subjects. Logistic regression analysis was used to evaluate the association between arterial stenosis in 2D TOF-MRA and low back pain and sciatica symptoms (intensity, duration, frequency). Results: Comparing 2D TOF-MRA and ceMRA images, the kappa value (95% confidence interval) was 0.52 (0.31-0.73). The intraobserver reliability kappa value for 2D TOF-MRA was 0.85 (0.77-0.92), and interobserver kappa was 0.57 (0.49-0.65). The sensitivity of 2D TOF-MRA in detecting stenosis was 0.58, the accuracy 0.89, and the specificity 0.94. In 97 (43%) subjects all arteries were normal, whereas 130 (57%) had at least one stenosed artery. The left L4 artery was most often affected. The degree of arterial stenosis was associated with intensity of low back and sciatic pain, and sciatica pain duration during the past 3 months. Conclusion: 2D TOF-MRA is an acceptable imaging method for arterial stenosis compared to ceMRA. Arterial stenosis was associated with subjective pain symptoms, indicating a role of decreased nutrition in spinal disorders

  17. Magnetic resonance tomographic angiography: diagnostic value in trigeminal neuralgia

    Energy Technology Data Exchange (ETDEWEB)

    Umehara, F. [Third Dept. of Internal Medicine, Faculty of Medicine, Kagoshima Univ. (Japan); Kamishima, K. [Div. of Diagnostic Neuroradiology, Kagoshima Univ. (Japan); Kashio, N. [Third Dept. of Internal Medicine, Faculty of Medicine, Kagoshima Univ. (Japan); Yamaguchi, K. [Div. of Diagnostic Neuroradiology, Kagoshima Univ. (Japan); Sakimoto, T.; Osame, M. [Third Dept. of Internal Medicine, Faculty of Medicine, Kagoshima Univ. (Japan)

    1995-07-01

    A combination of MRI, MR angiography and MR tomographic angiography (MRTA) was used to study the relationship of the root exit zone of the trigeminal nerve to surrounding vascular structures in seven patients with trigeminal neuralgia (TN) and ten patients with no evidence at a lesion in this region. MRTA is the technique for showing the relationship between vessels, cranial nerves and brain stem. MRTA clearly demonstrated the presence of a vessel at the root exit zone of the trigeminal nerve in all patients with TN. In the ten other patients, examination of 20 trigeminal nerves revealed that only one nerve (5%) was in contact with a vessel at the root exit zone. This study supports vascular compression of trigeminal nerves as a cause of TN, and demonstrates the value of MRTA as noninvasive technique for demonstrating compression. (orig.)

  18. Gadolinium-enhanced magnetic resonance angiography in brain death

    Science.gov (United States)

    Luchtmann, M.; Beuing, O.; Skalej, M.; Kohl, J.; Serowy, S.; Bernarding, J.; Firsching, R.

    2014-01-01

    Confirmatory tests for the diagnosis of brain death in addition to clinical findings may shorten observation time required in some countries and may add certainty to the diagnosis under specific circumstances. The practicability of Gadolinium-enhanced magnetic resonance angiography to confirm cerebral circulatory arrest was assessed after the diagnosis of brain death in 15 patients using a 1.5 Tesla MRI scanner. In all 15 patients extracranial blood flow distal to the external carotid arteries was undisturbed. In 14 patients no contrast medium was noted within intracerebral vessels above the proximal level of the intracerebral arteries. In one patient more distal segments of the anterior and middle cerebral arteries (A3 and M3) were filled with contrast medium. Gadolinium-enhanced MRA may be considered conclusive evidence of cerebral circulatory arrest, when major intracranial vessels fail to fill with contrast medium while extracranial vessels show normal blood flow.

  19. Magnetic resonance angiography and CT angiography of persistent primitive olfactory artery: Incidence and association rate with aneurysm in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Bo Ra; Yeo, Soo Hyun; Chang, Hyuk Won; Kim, Mi Jeong; Lee, Sung Moon; Kim, Ealmaan; Kim, Mi Kyung; Cho, Ho Chan; Kim, Hye Soon [Keimyung University College of Medicine, Daegu (Korea, Republic of)

    2012-06-15

    Japanese data indicates an incidence of persistent primitive olfactory artery (PPOA) of 0.14%. We studied the incidence of PPOA and associated cerebral vascular variation or anomalies in Korea. We retrospectively reviewed cranial magnetic resonance angiography (MRA) and computed tomography angiography (CTA) images of a total of 9841 patients of our institution. The diagnostic criterion of PPOA is extreme anterioinferior course of the proximal anterior cerebral artery, with a hairpin turn of the lateral projection. We found 29 cases (0.29%) with PPOA. The PPOA location was on the left in 19 cases, bilateral in 3 cases, and on the right in 7 cases. An aneurysm was found at the hairpin turn in 2 patients. There were aneurysms in other sites in 3 cases. There were hypoplasia of anterior cerebral artery in 3 cases, and fenestration of intracranial artery in 1 case. In Korean populations, the incidence of PPOA found in MRA and CTA was twice as high as that shown in the previous Japanese data. Within Korea, left side laterality is more common than right side or bilalterality. Aneurysmal dilatations at the hairpin turning point and aneurysms at other sites were found, and other vascular variations were observed in several cases.

  20. Magnetic resonance angiography evidence of vasospasm in children with suspected acute hemiplegic migraine.

    Science.gov (United States)

    Safier, Robert; Cleves-Bayon, Catalina; Vaisleib, Inna; Siddiqui, Ali; Zuccoli, Giulio

    2014-06-01

    Hemiplegic migraine is a rare subtype of migraine that is differentiated by motor weakness in the aura phase. The purpose of this case series was to examine the magnetic resonance angiogram findings of patients suffering from suspected acute hemiplegic migraine. This was a retrospective institutional board review protocol study of 8 patients. All patients received full brain magnetic resonance imaging under a 1.5-T magnet. The scans were subsequently evaluated by a neuroradiologist and 2 neurologists who were blinded to the study. The magnetic resonance angiogram findings of this study showed the presence of vasospasm within the intracranial vasculature during suspected acute hemiplegic migraine. This case series suggests that routine use of magnetic resonance angiography might be beneficial in both managing patients with acute hemiplegic migraine and helping to further understand the pathophysiology of this complicated disease process.

  1. Atherosclerosis measured by whole body magnetic resonance angiography and carotid artery ultrasound is related to arterial compliance, but not to endothelium-dependent vasodilation - the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study.

    Science.gov (United States)

    Lind, Lars; Andersson, Jessika; Hansen, Tomas; Johansson, Lars; Ahlström, Håkan

    2009-09-01

    Arterial compliance and endothelium-dependent vasodilation are two characteristics of the vessel wall. In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, we studied the relationships between arterial compliance and endothelium-dependent vasodilation versus atherosclerosis as measured with two imaging modalities. In the population-based PIVUS study (1016 subjects aged 70), arterial compliance was determined by ultrasound in the carotid artery and the stroke volume to pulse pressure ratio by echocardiography, while endothelium-dependent vasodilation was assessed by the invasive forearm technique with acetylcholine and brachial artery ultrasound. Intima-media thickness was evaluated by ultrasound in the carotid artery (n = 954). Stenosis in the carotid, aorta, renal, upper and lower leg arteries were determined by magnetic resonance angiography in a random subsample of 306 subjects. After adjustments for gender, Framingham risk score, obesity, myocardial infarction and stroke, distensibility in the carotid artery and the stroke volume to pulse pressure ratio were both significantly related to a weighted index of stenosis in the five arterial territories evaluated by magnetic resonance angiography (p<0.02 for both). Distensibility in the carotid artery (P = 0.021), but not the stroke volume to pulse pressure ratio (P = 0.08), was also significantly related to intima-media thickness. In the elderly population, atherosclerosis is mainly related to arterial compliance, but not to endothelium-dependent vasodilation in peripheral conduit or resistance vessels.

  2. Diagnostic role of magnetic resonance angiography in Swyer James syndrome: Case series of two cases

    Directory of Open Access Journals (Sweden)

    Parashari Umesh

    2010-01-01

    Full Text Available Swyer James syndrome is a rare syndrome which occurs due to viral illness in early childhood. The post infective obliterative bronchiolitis results in arrest of lung growth and alveolarization with reduced vascularity resulting in classical radiological features. We describe two cases of patients fulfilling all the criteria of the syndrome - 1 Unilateral hyperlucent small lung in chest radiograph with air trapping on expiration, small ipsilateral hila and pulmonary artery. 2 Diffuse decrease in attenuation of lung parenchyma with bronchiectasis and reduction in vascularity. 3 Unilateral pruned tree appearance on angiography (MRA. The clinical presentation was recurrent chest infection in a child and infrequent bouts of hemoptysis in a middle aged female. The study demonstrates the role of magnetic resonance angiography in diagnosing the condition.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-11-15

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

  4. 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.)

  5. Subsecond magnetic resonance angiography and the evaluation of abnormal arteriovasuclar communications

    Science.gov (United States)

    Zachariah, Anish B.; Pereles, F. S.; Kaliney, Ryan; Carr, James C.; Collins, Jeremy D.; Wood, Cecil; Finn, John P.

    2003-05-01

    Magnetic resonance (MR) angiography is becoming widely accepted in the diagnosis of vascular diseases. When used for evaluation of arterial stenoses, aneurysm, thrombosis, or occlusion, MR angiography is a robust and accurate technique. Traditional techniques for contrast-enhanced magnetic resonance angiography (MRA) offer the benefit of high spatial resolution in characterizing vascular malformations, but have lacked the temporal resolution to describe dynamic flow events. The purpose of this project is to demonstrate the potential role of a novel technique, sub-second MRA, in the evaluation of abdominal arteriovenous malformation.

  6. Improved Cerebral Time-of-Flight Magnetic Resonance Angiography at 7 Tesla – Feasibility Study and Preliminary Results Using Optimized Venous Saturation Pulses

    Science.gov (United States)

    Wrede, Karsten H.; Johst, Sören; Dammann, Philipp; Özkan, Neriman; Mönninghoff, Christoph; Kraemer, Markus; Maderwald, Stefan; Ladd, Mark E.; Sure, Ulrich; Umutlu, Lale; Schlamann, Marc

    2014-01-01

    Purpose Conventional saturation pulses cannot be used for 7 Tesla ultra-high-resolution time-of-flight magnetic resonance angiography (TOF MRA) due to specific absorption rate (SAR) limitations. We overcome these limitations by utilizing low flip angle, variable rate selective excitation (VERSE) algorithm saturation pulses. Material and Methods Twenty-five neurosurgical patients (male n = 8, female n = 17; average age 49.64 years; range 26–70 years) with different intracranial vascular pathologies were enrolled in this trial. All patients were examined with a 7 Tesla (Magnetom 7 T, Siemens) whole body scanner system utilizing a dedicated 32-channel head coil. For venous saturation pulses a 35° flip angle was applied. Two neuroradiologists evaluated the delineation of arterial vessels in the Circle of Willis, delineation of vascular pathologies, presence of artifacts, vessel-tissue contrast and overall image quality of TOF MRA scans in consensus on a five-point scale. Normalized signal intensities in the confluence of venous sinuses, M1 segment of left middle cerebral artery and adjacent gray matter were measured and vessel-tissue contrasts were calculated. Results Ratings for the majority of patients ranged between good and excellent for most of the evaluated features. Venous saturation was sufficient for all cases with minor artifacts in arteriovenous malformations and arteriovenous fistulas. Quantitative signal intensity measurements showed high vessel-tissue contrast for confluence of venous sinuses, M1 segment of left middle cerebral artery and adjacent gray matter. Conclusion The use of novel low flip angle VERSE algorithm pulses for saturation of venous vessels can overcome SAR limitations in 7 Tesla ultra-high-resolution TOF MRA. Our protocol is suitable for clinical application with excellent image quality for delineation of various intracranial vascular pathologies. PMID:25232868

  7. Whole-body magnetic resonance angiography at 3 tesla using a hybrid protocol in patients with peripheral arterial disease

    DEFF Research Database (Denmark)

    Nielsen, Yousef W; Eiberg, Jonas P; Logager, Vibeke B

    2009-01-01

    The purpose of this study was to determine the diagnostic performance of 3T whole-body magnetic resonance angiography (WB-MRA) using a hybrid protocol in comparison with a standard protocol in patients with peripheral arterial disease (PAD). In 26 consecutive patients with PAD two different proto...

  8. Chronic hepatosplenic schistosomiasis mansoni: magnetic resonance imaging and magnetic resonance angiography findings

    Energy Technology Data Exchange (ETDEWEB)

    Bezerra, A.S.; D' Ippolito, G.; Caldana, R.P.; Cecin, A.O.; Ahmed, M.; Szejnfeld, J. [Dept. of Diagnostic Imaging, Federal Univ. of Sao Paulo, Sao Paulo (Brazil)

    2007-02-15

    Purpose: To evaluate the hepatosplenic manifestations and the portal venous system in patients with chronic infection by Schistosoma mansoni. Material and Methods: A cross-sectional observational study was performed in 28 patients with chronic hepatosplenic schistosomiasis submitted to magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) of the abdomen. Images were interpreted independently by two radiologists to determine the reproducibility of image interpretation and who evaluated the presence of morphological alterations in the liver and spleen, such as hepatosplenomegaly, hepatic fissure widening, periportal fibrosis, and the presence of siderotic nodules. Interobserver and intra-observer agreement were measured with the kappa and intraclass correlation tests. Evaluation of venous collateral pathways and portal and splenic veins was done in consensus by both examiners. Results: Observers identified enlargement of the left lobe (78.5-92.8%) and caudate-to-right-lobe ratio (78.5-92.8%), irregularity of hepatic contours (89.2-96.4%), fissure widening (89.2-100%), and splenic siderotic nodules (84.2%). Splenomegaly, heterogeneity of hepatic parenchyma, peripheral hepatic vessels, and periportal fibrosis were observed in 100% of patients. MRI findings presented almost perfect interobserver (kappa 0.65-1) and intra-observer (kappa = 0.73-1 for observer 1, and kappa = 0.65-1 for observer 2) agreement for the variables analyzed. MRA showed the presence of collateral pathways in the majority of patients (71.4%) along with widening of portal and splenic veins. Conclusion: Using MRI, hepatosplenic alterations in schistosomiasis are characterized by heterogeneity of hepatic parenchyma, presence of peripheral perihepatic vessels, periportal fibrosis, splenomegaly, siderotic nodules, and the presence of venous collateral pathways.

  9. 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.

  10. Magnetic resonance angiography of the brain: review of 100 cases; Angiorresonancia magnetica do cranio: revisao de 100 casos

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Leonardo Portugal Guimaraes [Hospital da Benficencia Portuguesa de Niteroi, RJ (Brazil). Scan Diagnosticos por Imagem; Santos, Alair Augusto S.M. D. dos; Marchiori, Edson [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Radiologia]. E-mail: lpgamaral@yahoo.com.br

    2004-06-01

    In this study we reviewed the scans of 100 patients submitted to magnetic resonance angiography (MR angiography) of the brain for different clinical indications. The objectives of the study were to discuss the advantages and disadvantages of the 3D TOF in cerebral MR angiography, to review the main indications of MR angiography in the evaluation of intracranial vascular lesions, and to assess the frequency of the most important findings. The main indications for MR angiography were headache (n = 29), stroke (n = 14), transient ischemic attack (n = 11) and other causes (n = 35). In 11 patients the clinical indication could not be recovered from the patients records. Fifty two percent of the exams showed abnormalities. The main findings were vascular stenosis (n = 30), aneurysm (n = 10), anatomical variants (n = 6), vascular malformations (n = 4) and dural sinuses thrombosis (n = 2). The 3D TOF technique, the only technique applied in this study, proved to be efficient in most of the cases, requiring a relatively short acquisition time. One of the disadvantages was the lack of efficiency in covering large volume areas. (author)

  11. Catheter Angiography

    Medline Plus

    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 ...

  12. Whole-body magnetic resonance angiography of patients using a standard clinical scanner

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Tomas; Wikstroem, Johan; Eriksson, Mats-Ola; Lundberg, Anders; Ahlstroem, Haakan [Uppsala University Hospital, Department of Diagnostic Radiology, Uppsala (Sweden); Johansson, Lars [Uppsala University Hospital, Uppsala (Sweden); Ljungman, Christer [Uppsala University Hospital, Department of Vascular Surgery, Uppsala (Sweden); Hoogeven, Romhild [Philips Medical Systems, MR Clinical Science, Best (Netherlands)

    2006-01-01

    The purpose of this study was to evaluate the technique of whole-body magnetic resonance angiography (MRA) of patients with a standard clinical scanner. Thirty-three patients referred for stenoses, occlusions, aneurysms, assessment of patency of vascular grafts, vasculitis and vascular aplasia were examined in a 1.5-T scanner using its standard body coil. Three-dimensional sequences were acquired in four stations after administration of one intravenous injection of 40 ml conventional gadolinium contrast agent. Different vessel segments were evaluated as either diagnostic or nondiagnostic and regarding the presence of stenoses with more than 50% diameter reduction, occlusions or aneurysms. Of 923 vessel segments, 67 were not evaluable because of poor contrast filling (n=31), motion artefacts (n=20), venous overlap (n=12) and other reasons (n=4). Stenoses of more than 50%, occlusions or aneurysms were observed in 26 patients (129 segments). In nine patients additional unsuspected pathology was found. In 10 out of 14 patients (71/79 segments) there was conformity between MRA and digital subtraction angiography regarding the grade of stenosis. This study shows that whole-body MRA with a standard clinical scanner is feasible. Motion artefacts and the timing of the contrast agent through the different segments are still problems to be solved. (orig.)

  13. Factors in the technical quality of gadolinium enhanced magnetic resonance angiography for pulmonary embolism in PIOPED III

    OpenAIRE

    Sostman, H. Dirk; Jablonski, Kathleen A.; Woodard, Pamela K.; Stein, Paul D.; Naidich, David P.; Chenevert, Thomas L.; Weg, John G.; Hales, Charles A.; Hull, Russell D.; Goodman, Lawrence R.; Tapson, Victor F

    2011-01-01

    In a multi-center trial, gadolinium enhanced magnetic resonance angiography (MRA) for diagnosis of acute pulmonary embolism (PE) had a high rate of technically inadequate images. Accordingly, we evaluated the reasons for poor quality MRA of the pulmonary arteries in these patients. We performed a retrospective analysis of the data collected in the PIOPED III study. We assessed the relationship to the proportion of examinations deemed “uninterpretable” by central readers to the clinical center...

  14. Diagnostic Performance of Combined Contrast-Enhanced Magnetic Resonance Angiography and Phase-Contrast Magnetic Resonance Imaging in Suspected Subclavian Steal Syndrome.

    Science.gov (United States)

    Tsao, Teng-Fu; Cheng, Kai-Lun; Shen, Chao-Yu; Wu, Ming-Chi; Huang, Hsin-Hui; Su, Chun-Hung; Chen, Fong-Lin; Tyan, Yeu-Sheng; Lin, Yung-Chang

    2016-05-01

    The study sought to evaluate the efficacy of magnetic resonance imaging (MRI) in patients with suspected subclavian steal syndrome (SSS) using both contrast-enhanced (CE) MR angiography and phase-contrast (PC) MRI. Fifteen suspected SSSs from 13 patients were evaluated using CE-MR angiography and PC-MRI. Ten patients also received dynamic CE-MR angiography. All MRI examinations were technically successful. By combining CE-MR angiography with PC-MRI, 10 SSSs were diagnosed in 9 patients. The delay enhancement dynamic technique predicted SSS with a sensitivity, specificity, and accuracy of 57.1%, 100%, and 72.7%, respectively. Without the dynamic technique, affected delay-enhanced arteries were poorly visualized and could be mistaken for occluded vessels. Retrograde vertebral flow by PC-MRI was used to predict ipsilateral SSS with a sensitivity, specificity, and accuracy of 100%, 60%, and 86.7%, respectively. There were 2 false positives including 1 patient with a proximal total occlusion of the affected vertebral artery and another with brachiocephalic steal syndrome rather than SSS. This suggested that retrograde vertebral flow does not always indicate SSS. CE-MR angiography combined with PC-MRI is efficacious when evaluating SSS in clinical practice. Copyright © 2016 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

  15. The increased use of computed tomography angiography and magnetic resonance angiography as the sole imaging modalities prior to infrainguinal bypass has had no effect on outcomes.

    Science.gov (United States)

    Shue, Bing; Damle, Rachelle N; Flahive, Julie; Kalish, Jeffrey A; Stone, David H; Patel, Virendra I; Schanzer, Andres; Baril, Donald T

    2015-08-01

    Angiography remains the gold standard imaging modality before infrainguinal bypass. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) have emerged as noninvasive alternatives for preoperative imaging. We sought to examine contemporary trends in the utilization of CTA and MRA as isolated imaging modalities before infrainguinal bypass and to compare outcomes following infrainguinal bypass in patients who underwent CTA or MRA versus those who underwent conventional arteriography. Patients undergoing infrainguinal bypass within the Vascular Study Group of New England were identified (2003-2012). Patients were stratified by preoperative imaging modality: CTA/MRA alone or conventional angiography. Trends in utilization of these modalities were examined and demographics of these groups were compared. Primary end points included primary patency, secondary patency, and major adverse limb events (MALE) at 1 year as determined by Kaplan-Meier analysis. Multivariable Cox proportional hazards models were constructed to evaluate the effect of imaging modality on primary patency, secondary patency, and MALE after adjusting for confounders. In 3123 infrainguinal bypasses, CTA/MRA alone was used in 462 cases (15%) and angiography was used in 2661 cases (85%). Use of CTA/MRA alone increased over time, with 52 (11%) bypasses performed between 2003 and 2005, 189 (41%) bypasses performed between 2006 and 2009, and 221 (48%) bypasses performed between 2010 and 2012 (P < 0.001). Patients with CTA/MRA alone, compared with patients with angiography, more frequently underwent bypass for claudication (33% vs. 26%, P = 0.001) or acute limb ischemia (13% vs. 5%, P < 0.0001), more frequently had prosthetic conduits (39% vs. 30%, P = 0.001), and less frequently had tibial/pedal targets (32% vs. 40%, P = 0.002). After adjusting for these and other confounders, multivariable analysis demonstrated that the use of CTA/MRA alone was not associated with a significant

  16. Transient cortical blindness: a benign but devastating complication after coronary angiography and graft study.

    Science.gov (United States)

    Sridhar, Ganiga Srinivasaiah; Sadiq, Muhammad Athar; Wan Ahmad, Wan Azman; Supuramaniam, Chitra; Undok, Abdul Wahab; Abidin, Imran Zainal; Chee, Kok Han

    2014-10-01

    Transient cortical blindness after coronary angiography and bypass graft is a very rare complication. In this report we present the case of a 63-year-old man who developed transient cortical blindness within 30 minutes of coronary angioplasty and graft study, but subsequently recovered within 72 hours without any neurological deficit. A plain computed tomography brain scan showed bilateral symmetrical subarachnoid hyperdensities in the posterior cerebral circulation area suspicious of subarachnoid bleed. However, magnetic resonance imaging and magnetic resonance angiography scans were normal. Excess contrast volume causing direct neurotoxicity seems to be the most probable cause, but the exact mechanism is unclear.

  17. Optimal velocity encoding during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography

    Institute of Scientific and Technical Information of China (English)

    Gang Guo; Yonggui Yang; Weiqun Yang

    2011-01-01

    This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-contrast magnetic resonance angiography slice was applied perpendicular to the internal carotid artery and the vertebral artery at C2 level. For each subject, the velocity encoding was set from 30 to 90 cm/s with an interval of 10 cm/s for a total of seven settings. Various velocity encodings greatly affected blood flow volume, maximal blood flow velocity and mean blood flow velocity in the internal carotid artery, but did not significantly affect vertebral arteries and jugular veins. When velocity encoding was 60-80 cm/s, the inflow blood volume was 655 ± 118 mL/min, and the outflow volume was 506 ± 186 mL/min. The ratio of outflow/inflow was steady at 0.78-0.83, and there was no aliasing in any of the images. These findings suggest that velocity encodings of 60-80 cm/s should be selected during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography.

  18. Magnetic Resonance Imaging and Angiography for the Prerupture Diagnosis of Rudimentary Uterine Horn Pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Ozeren, S.; Caliskan, E.; Corakci, A.; Ozkan, S.; Demirci, A. [Kocaeli Univ., Faculty of Medicine, Kocaeli (Turkey). Dept. of Obstetrics and Gynecology

    2004-12-01

    Magnetic resonance (MR) imaging and MR angiography were used for the differential diagnosis and preoperative planning of a 17 weeks of age rudimentary horn pregnancy. A 26-year-old primigravida was referred to our hospital with a preliminary diagnosis of abdominal pregnancy. After an inconclusive ultrasound evaluation we were able to identify a rudimentary horn pregnancy, extent of the placental invasion, and the vascular supply via MR imaging and time of flight sequence MR angiography. The obtained data were also used for preoperative planning, which resulted in an uncomplicated, prerupture laparotomy for pregnancy termination and a healthy female.

  19. Arterial Obstruction on Computed Tomographic or Magnetic Resonance Angiography and Response to Intravenous Thrombolytics in Ischemic Stroke.

    Science.gov (United States)

    Mair, Grant; von Kummer, Rüdiger; Adami, Alessandro; White, Philip M; Adams, Matthew E; Yan, Bernard; Demchuk, Andrew M; Farrall, Andrew J; Sellar, Robin J; Sakka, Eleni; Palmer, Jeb; Perry, David; Lindley, Richard I; Sandercock, Peter A G; Wardlaw, Joanna M

    2017-02-01

    Computed tomographic angiography and magnetic resonance angiography are used increasingly to assess arterial patency in patients with ischemic stroke. We determined which baseline angiography features predict response to intravenous thrombolytics in ischemic stroke using randomized controlled trial data. We analyzed angiograms from the IST-3 (Third International Stroke Trial), an international, multicenter, prospective, randomized controlled trial of intravenous alteplase. Readers, masked to clinical, treatment, and outcome data, assessed prerandomization computed tomographic angiography and magnetic resonance angiography for presence, extent, location, and completeness of obstruction and collaterals. We compared angiography findings to 6-month functional outcome (Oxford Handicap Scale) and tested for interactions with alteplase, using ordinal regression in adjusted analyses. We also meta-analyzed all available angiography data from other randomized controlled trials of intravenous thrombolytics. In IST-3, 300 patients had prerandomization angiography (computed tomographic angiography=271 and magnetic resonance angiography=29). On multivariable analysis, more extensive angiographic obstruction and poor collaterals independently predicted poor outcome (P1 indicates benefit) in patients with (odds ratio, 2.07; 95% confidence interval, 1.18-3.64; P=0.011) versus without (odds ratio, 0.88; 95% confidence interval, 0.58-1.35; P=0.566) arterial obstruction (P for interaction 0.017). Intravenous thrombolytics provide benefit to stroke patients with computed tomographic angiography or magnetic resonance angiography evidence of arterial obstruction, but the sample was underpowered to demonstrate significant treatment benefit or harm among patients with apparently patent arteries. URL: http://www.isrctn.com. Unique identifier: ISRCTN25765518. © 2016 The Authors.

  20. Arterial Obstruction on Computed Tomographic or Magnetic Resonance Angiography and Response to Intravenous Thrombolytics in Ischemic Stroke

    Science.gov (United States)

    Mair, Grant; von Kummer, Rüdiger; Adami, Alessandro; White, Philip M.; Adams, Matthew E.; Yan, Bernard; Demchuk, Andrew M.; Farrall, Andrew J.; Sellar, Robin J.; Sakka, Eleni; Palmer, Jeb; Perry, David; Lindley, Richard I.; Sandercock, Peter A.G.

    2017-01-01

    Background and Purpose— Computed tomographic angiography and magnetic resonance angiography are used increasingly to assess arterial patency in patients with ischemic stroke. We determined which baseline angiography features predict response to intravenous thrombolytics in ischemic stroke using randomized controlled trial data. Methods— We analyzed angiograms from the IST-3 (Third International Stroke Trial), an international, multicenter, prospective, randomized controlled trial of intravenous alteplase. Readers, masked to clinical, treatment, and outcome data, assessed prerandomization computed tomographic angiography and magnetic resonance angiography for presence, extent, location, and completeness of obstruction and collaterals. We compared angiography findings to 6-month functional outcome (Oxford Handicap Scale) and tested for interactions with alteplase, using ordinal regression in adjusted analyses. We also meta-analyzed all available angiography data from other randomized controlled trials of intravenous thrombolytics. Results— In IST-3, 300 patients had prerandomization angiography (computed tomographic angiography=271 and magnetic resonance angiography=29). On multivariable analysis, more extensive angiographic obstruction and poor collaterals independently predicted poor outcome (PHandicap Scale (P≥0.075) in IST-3. In meta-analysis (5 trials of alteplase or desmoteplase, including IST-3, n=591), there was a significantly increased benefit of thrombolytics on outcome (odds ratio>1 indicates benefit) in patients with (odds ratio, 2.07; 95% confidence interval, 1.18–3.64; P=0.011) versus without (odds ratio, 0.88; 95% confidence interval, 0.58–1.35; P=0.566) arterial obstruction (P for interaction 0.017). Conclusions— Intravenous thrombolytics provide benefit to stroke patients with computed tomographic angiography or magnetic resonance angiography evidence of arterial obstruction, but the sample was underpowered to demonstrate significant

  1. Magnetic Resonance Angiography in the Pig using Hyperpolarized Water

    DEFF Research Database (Denmark)

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

    , the acquisition time is several minutes, and conventional MRA methods thus fail to image within a single respiration or heartbeat and therefore suffers from motion artefacts. We demonstrate that hyperpolarized (HP) water can be used as an imaging agent to provide subsecond angiographies in pigs. Previous work...... sequence with 5 ° flip angle, slice thickness of 40 mm, TR = 3.4 ms, TE = 0.9840 ms, 256x256 matrix, FOV = (140 mm)2. The acquisition time is 870 ms. 15 mL HP substance is injected over 5 s, initiated 15 s after dissolution through a catheter in the right renal artery of a 40 kg pig. Results The protons...

  2. Discordance between CT and angiography in the PIOPED II study.

    Science.gov (United States)

    Wittram, Conrad; Waltman, Arthur C; Shepard, Jo-Anne O; Halpern, Elkan; Goodman, Lawrence R

    2007-09-01

    To retrospectively evaluate the causes of discordant computed tomographic (CT)-angiographic readings from the Prospective Investigation of Pulmonary Embolism Diagnosis, or PIOPED, II study. Institutional review board approval was obtained for this HIPAA-compliant study. Of 1036 patients suspected of having pulmonary embolism who were examined with CT, 226 underwent angiography; 206 patients had concordant results and 20 had discordant results according to two independent readers. Of these 20 patients, 10 were men and 10 were women (mean age, 49 years). Among the 20 studies with discordant results, central readers identified seven cases as negative and 13 as positive for pulmonary embolism at CT; these findings were reversed at angiography. Side-by-side comparisons of discordant studies were performed in consensus. The time between CT and angiography and all locations of pulmonary embolism vascular territory were recorded. The McNemar binomial test was used. One patient had false-positive findings at angiography, 13 patients had false-negative findings at angiography, and two patients had false-negative findings at CT. Four patients had true-negative findings at CT; however, findings were positive for thrombus at angiography. The sensitivity for the detection of pulmonary embolism was 87% for CT and 32% for angiography (P=.007). The largest missed thrombus at angiography was subsegmental in eight patients, segmental in two patients, and lobar in three patients; at CT it was subsegmental in two patients. The mean time between CT and angiography was 40 hours+/-21 (standard deviation) (range, 10-97 hours). In the interval between CT and angiography, thrombi can remain the same, resolve, develop, or result from angiography. Copyright (c) RSNA, 2007.

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

    Science.gov (United States)

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

    2006-01-01

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

  4. Blood Pool Contrast-enhanced Magnetic Resonance Angiography with Correlation to Digital Subtraction Angiography: A Pictorial Review

    Directory of Open Access Journals (Sweden)

    Martha-Grace Knuttinen

    2014-01-01

    Full Text Available Magnetic resonance angiography (MRA provides noninvasive visualization of the vascular supply of soft tissue masses and vascular pathology, without harmful radiation. This is important for planning an endovascular intervention, and helps to evaluate the efficiency and effectiveness of the treatment. MRA with conventional extracellular contrast agents relies on accurate contrast bolus timing, limiting the imaging window to first-pass arterial phase. The recently introduced blood pool contrast agent (BPCA, gadofosveset trisodium, reversibly binds to human serum albumin, resulting in increased T1 relaxivity and prolonged intravascular retention time, permitting both first-pass and steady-state phase high-resolution imaging. In our practice, high-quality MRA serves as a detailed "roadmap" for the needed endovascular intervention. Cases of aortoiliac occlusive disease, inferior vena cava thrombus, pelvic congestion syndrome, and lower extremity arteriovenous malformation are discussed in this article. MRA was acquired at 1.5 T with an 8-channel phased array coil after intravenous administration of gadofosveset (0.03 mmol/kg body weight, at the first-pass phase. In the steady-state, serial T1-weighted 3D spoiled gradient echo images were obtained with high resolution. All patients underwent digital subtraction angiography (DSA and endovascular treatment. MRA and DSA findings of vascular anatomy and pathology are discussed and correlated. BPCA-enhanced MRA provides high-quality first-pass and steady-state vascular imaging. This could increase the diagnostic accuracy and create a detailed map for pre-intervention planning. Understanding the pharmacokinetics of BPCA and being familiar with the indications and technique of MRA are important for diagnosis and endovascular intervention.

  5. A free-breathing non-contrast-enhanced pulmonary magnetic resonance angiography at 3 Tesla

    Institute of Scientific and Technical Information of China (English)

    YANG Jian; WANG Wei; WANG Ya-rong; NIU Gang; JIN Chen-wang; WU Ed Xuekui

    2009-01-01

    Background The breathhold contrast-enhanced three-dimensional magnetic resonance angiography (MRA) using T1-weighted gradient-echo imaging sequence is the standard technique for MRA of the thorax. However, this technique is not desirable for certain patients with respiratory insufficiency, serious renal impairment, or allergy to contrast agents. The objective of this study was to optimize and evaluate a non-contrast-enhanced free-breathing pulmonary MRA protocol at 3 Tesla.Methods The time-of-flight protocol was based on a two-dimensional T1-weighted turbo field echo sequence with slice-selective inversion recovery and magnetization transfer preparation together with respiratory navigator gating, cardiac gating, and parallel imaging. Optimal values for time of inversion delay, flip angle and slice thickness were experimentally determined and used for all subjects.Results Excellent pulmonary MRA images, in which the 7th order branches of pulmonary arteries could be reliably identified, were obtained in the 12 free-breathing healthy volunteers. TI of ~300 ms provides the best suppression of background thoracic and cardiac muscles and effective inflow enhancement. With increasing flip angle, the pulmonary vessels gradually brightened and exhibited optimal contrast at 20°-30°. The 2 mm slice thickness and 0.5 mm slice overlap is suitable for visualization of the peripheral pulmonary vessel.Conclusions The MRA protocol at 3 Tesla may have clinical significance for pulmonary vascular imaging in patients who are not available for contrast-enhanced 3D MRA and CT angiography examination or are unable to sustain a long breath-hold.

  6. Standardized Volume Rendering for Magnetic Resonance Angiography Measurements in the Abdominal Aorta

    Energy Technology Data Exchange (ETDEWEB)

    Persson, A.; Brismar, T.B.; Lundstroem, C.; Dahlstroem, N.; Othberg, F.; Smedby, Oe. [Linkoeping Univ. Hospital (Sweden). Center for Medical Image Science and Visualization (CMIV)

    2006-03-15

    Purpose: To compare three methods for standardizing volume rendering technique (VRT) protocols by studying aortic diameter measurements in magnetic resonance angiography (MRA) datasets. Material and Methods: Datasets from 20 patients previously examined with gadolinium-enhanced MRA and with digital subtraction angiography (DSA) for abdominal aortic aneurysm were retrospectively evaluated by three independent readers. The MRA datasets were viewed using VRT with three different standardized transfer functions: the percentile method (Pc-VRT), the maximum-likelihood method (ML-VRT), and the partial range histogram method (PRH-VRT). The aortic diameters obtained with these three methods were compared with freely chosen VRT parameters (F-VRT) and with maximum intensity projection (MIP) concerning inter-reader variability and agreement with the reference method DSA. Results: F-VRT parameters and PRH-VRT gave significantly higher diameter values than DSA, whereas Pc-VRT gave significantly lower values than DSA. The highest interobserver variability was found for F-VRT parameters and MIP, and the lowest for Pc-VRT and PRH-VRT. All standardized VRT methods were significantly superior to both MIP and F-VRT in this respect. The agreement with DSA was best for PRH-VRT, which was the only method with a mean error below 1 mm and which also had the narrowest limits of agreement (95% of cases between 2.1 mm below and 3.1 mm above DSA). Conclusion: All the standardized VRT methods compare favorably with MIP and VRT with freely selected parameters as regards interobserver variability. The partial range histogram method, although systematically overestimating vessel diameters, gives results closest to those of DSA.

  7. Comparison of three-dimensional volume-targeted thin-slab FIESTA magnetic resonance angiography and 64-multidetector computed tomographic angiography for the identification of proximal coronary stenosis.

    Science.gov (United States)

    Cheng, Liuquan; Ma, Lin; Schoenhagen, Paul; Ye, Huiyi; Lou, Xin; Gao, Yuangui; Zhao, Xihai; Wang, Xinjiang; Dong, Wei

    2013-09-10

    Based on recent clinical data, an imaging strategy of identifying proximal coronary disease allows further management decisions in patients with stable angina pectoris. We aimed to compare diagnostic accuracy of non-contrast fast steady-state (FIESTA) magnetic resonance angiography (MRA) with 64-multidetector computed tomographic angiography (CTA), using conventional coronary angiography (CA) as the reference standard. Thirty patients with suspected coronary artery disease consented to participate in an institutional review board-approved protocol. Coronary MRA was performed at 1.5 T using a respiratory navigator and electrocardiogram-gated three-dimensional FIESTA pulse sequence. CTA images were acquired using a 64-multidetector computed tomographic scanner, using beta blockade to reduce the heart rate to less than 70 bpm. Coronary luminal stenosis >50% was identified. Plaques were classified as non-calcified, mixed, or calcified on CTA, and as high-, intermediate-, or low-signal on FIESTA MRA. Compared to CA, the sensitivity, specificity, and overall accuracy for detection of >50% proximal coronary stenoses were 83.0%, 86.9%, and 86.1% for MRA and 85.1%, 87.2%, and 86.8% for CTA, respectively. For the 24 calcified stenoses, MRA corrected 16 segments that overestimated on CTA and MRA had an accuracy of 75% in evaluating calcified plaques. High-resolution three-dimensional FIESTA MRA and CTA have a similar accuracy in detecting proximal coronary stenosis. The clinical impact of identification of proximal disease in patients with stable CAD needs to be examined in future studies. Copyright © 2012. Published by Elsevier Ireland Ltd.

  8. Magnetic resonance pulmonary angiography and direct imaging of embolus for the detection of pulmonary emboli.

    Science.gov (United States)

    Moody, A R; Liddicoat, A; Krarup, K

    1997-08-01

    The authors developed a two-dimensional breathhold magnetic resonance (MR) technique for the direct imaging of pulmonary emboli. In vitro MR imaging was performed to demonstrate the potential generation of clot-blood contrast by in vivo pulmonary embolism (PE). A two-dimensional magnetization prepared gradient-echo (turbo-FLASH) breathhold technique was designed to directly image intravascular emboli by the selective nulling of the blood signal. A turbo-FLASH pulmonary angiographic breathhold sequence was used to provide spatial localization of detected emboli. Thirteen patients with suspected PE were studied; 6 patients underwent conventional pulmonary angiography (CPA) and the remaining 7 had diagnoses based on findings from other studies. In vitro study of blood clot demonstrated an initial rise and then fall in T1 sufficient to generate clot-blood contrast after eight days of clot formation. All patients with CPA or alternative study evidence of PE were diagnosed as positive with direct embolus imaging MR. There were no false-positive diagnoses. Three additional emboli were detected using the MR technique compared with CPA. The MR pulmonary angiographic sequence provided a useful road map for localization of intravascular emboli but was less sensitive for PE detection than the embolus imaging technique. The direct imaging of PE is feasible using a simple two-dimensional breathhold technique.

  9. Prominent porto-systemic collateral pathways in patients with portal hypertension: demonstration by gadolinium-enhanced magnetic resonance angiography; Vias colaterais porto-sistemicas exuberantes em portadores de hipertensao portal: demonstracao pela angiografia por ressonancia magnetica com gadolinio

    Energy Technology Data Exchange (ETDEWEB)

    Caldana, Rogerio Pedreschi; Bezerra, Alexandre Araujo Sergio; Cecin, Alexnadre Oliveira; Souza, Luis Ronan Marques Ferreira de; Goldman, Susan Menasce; D' Ippolito, Giuseppe; Szejnfeld, Jacob [Universidade Federal de Sao Paulo (UNIFESP/EPM), Sao Paulo, SP (Brazil). Dept. de Diagnostico por Imagem]. E-mail: rogercal@uol.com.br

    2003-03-01

    To demonstrate the usefulness of gadolinium-enhanced magnetic resonance angiography in the evaluation of prominent porto-systemic collateral pathways. We reviewed the images from 40 patients with portal hypertension studied with gadolinium-enhanced magnetic resonance angiography and selected illustrative cases of prominent porto-systemic collateral pathways. The scans were performed using high field equipment (1.5 Tesla) and a 3 D volume technique. Image were obtained after intravenous injection of paramagnetic contrast media using a power injector. Magnetic resonance angiography demonstrated with precision the porto-systemic collateral pathways, particularly when investigating extensive territories or large vessels. The cases presented show the potential of this method in the investigation of patients with portal hypertension. Gadolinium-enhanced magnetic resonance angiography is a useful method for the evaluation of patients with portal hypertension and prominent collateral pathways. (author)

  10. Magnetic resonance angiography in potential live renal donors: a joint radiological and surgical evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Subramaniam, M.; Mizzi, A.; Roditi, G. E-mail: Giles.Roditi@northglasgow.scot.nhs.ukgilesroditi@mac.com

    2004-04-01

    AIM: To assess the impact of a joint surgical and radiological audit on the accuracy of contrast-enhanced magnetic resonance angiography (MRA) reports in the evaluation of potential renal donors. MATERIALS AND METHODS: We analysed the records of live renal donors who underwent gadolinium-enhanced MRA as part of the pre-operative evaluation to assess renal vasculature between August 1999 and July 2002 when feedback from surgical findings to radiology had been available. In cases of discrepancy between MRA reports and surgical findings, studies were retrieved from the magnetic resonance imaging (MRI) workstation and subjected to detailed joint clinical and radiological review. Scan quality was assessed and sources of discrepancy were identified. RESULTS: There were 45 donors, 23 men and 22 women with a mean age of 41 years. Reported MRA findings were fully confirmed at surgery in 38 of 45 cases. These images were not analysed further. In seven donors the findings at surgery were discrepant with the radiological reports: there were four cases of 'missed' early branches and three cases of 'missed' accessory arteries. In the first year of the audit there were four discrepant cases out of 18 (22%), all of which were radiological reporting errors. The number of discrepant cases in the second year was two out of 19 cases (11%). Neither of these was a radiological reporting error. There was one 'missed' early renal artery branch in the third year of audit, which was identified on MRA review. CONCLUSION: The study highlights the importance of detecting and clearly reporting not only accessory renal arteries, but also early renal arterial branches in the pre-operative evaluation of renal donors. The accuracy of pre-operative MRA in potential renal donors is high, but radiological reporting of MRA examinations is improved through careful clinical feedback, audit and interdisciplinary co-operation.

  11. Venous reflux on contrast-enhanced head and neck magnetic resonance angiography: Analysis of causative factors

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    Shin, Dong Jae; Lee, Eun Ja [Dept. of Radiology, Dongguk University Ilsan Hospital, Goyang (Korea, Republic of); Bae, Jong Myon [Dept. of Preventive Medicine, Jeju National University School of Medicine, Jeju (Korea, Republic of)

    2016-12-15

    The purpose of this study was to analyze the causative factors of venous reflux on contrast-enhanced head and neck magnetic resonance angiography. We retrospectively reviewed 150 patients with right-arm injections and 150 patients with left-arm injections. We included the age, gender, body mass index, history of hypertension, and history of diabetes mellitus in the evaluation of all patients. We measured the shortest width of the left or right brachiocephalic vein (BCV), the diameter of the aortic arch, and the distance between the sternum and vertebral body. The relationship between these factors and the venous reflux was analyzed. In patients with venous reflux, we performed qualitative image scoring for suboptimal images. In patients with venous reflux, the image quality of the left-arm injection group was significantly inferior to the image quality of the right-arm injection group. The mean age and the male-to-female ratio of patients with venous reflux were significantly higher than those of patients without venous reflux. In patients receiving the left-arm injection, the mean shortest width of the left BCV was significantly narrower in patients with venous reflux than in patients without venous reflux. A left-arm injection should be avoided, especially in elderly patients, to acquire an optimal image.

  12. Giant fibroma in the left ventricle of an infant: imaging findings in magnetic resonance imaging, echocardiography and angiography

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    Gutberlet, Matthias; Felix, Roland [Department of Radiology and Nuclear Medicine, Charite, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Abdul-Khaliq, Hashim; Stiller, Brigitte; Schubert, Ulf; Lange, Peter E. [Department of Pediatric Cardiology, Deutsches Herzzentrum, Berlin (Germany); Stoltenburg-Didinger, Gisela [Department of Neuropathology, Free University Berlin, Berlin (Germany); Hetzer, Roland [Department of Cardio-, Thoracic and Vascular Surgery, Deutsches Herzzentrum Berlin (Germany)

    2002-07-01

    The diagnosis of a rare case of giant intraventricular fibroma in an infant by MRI in comparison with other imaging modalities, such as echocardiography and angiography, is discussed. For preoperative planning only MRI showed the myocardial infiltration. The myocardial blood supply of the tumor could be evaluated qualitatively by contrast-enhanced MRI, but the direct visualization of the distally located branches could only be assessed by coronary angiography. Magnetic resonance coronary angiography using the navigator technique failed to depict the distal part of the coronaries. The obstruction of the left ventricle outflow tract could be assessed and quantified by all imaging modalities. (orig.)

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

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

    2000-09-01

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

  14. Assessing portal hypertension in post-operative biliary atresia patients using 2D magnetic resonance angiography

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    Hiki, Saori; Horikoshi, Kentarou; Kobayashi, Hiroyuki; Yamataka, Atsuyuki; Miyano, Takeshi; Kuwatsuru, Ryouhei; Katayama, Hitoshi [Juntendo Univ., Tokyo (Japan). School of Medicine

    2000-01-01

    2D magnetic resonance angiography (MRA) was performed in 38 post-operative biliary atresia (BA) patients. Collateral circulation other than esophageal varices that could not be observed with endoscopy was detected. By using contrast, the portal vasculature could be clearly delineated. MRA can be performed without using general anesthesia obviating the nead for hospitalization. At present, MRA alone is not sufficient for the complete assessment of varices in post-operative BA patients, and mucosal changes cannot be detected without endoscopy. However, combined with endoscopy, it provides valuable additional follow-up information without the need for general anesthesia or hospitalization. (author)

  15. CIRCLE OF WILLIS: VARIANT FORMS AND THEIR EMBRYOLOGY USING GROSS DISSECTION AND MAGNETIC RESONANCE ANGIOGRAPHY

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    Bishwajeet Saikia

    2014-06-01

    Full Text Available Background: The circle of Willis is a large arterial anastomotic ring present at the base of the brain uniting the internal carotid and the vertebrobasilar systems. Branches from the internal carotid and vertebral arteries anastomose to form an arterial circle in the basal cisterns and then distribute to supply the brain. The anatomy of the circle is known to vary significantly; the vessels may be absent or sufficiently narrowed altering the hemodynamics of the circle of Willis and affecting its role as a collateral route. These variant forms can be correlated to their phylogeny and embryology. Prior knowledge of these variant forms is important in pathologies and treatment (e.g. parent artery occlusion for carotid aneurysms resulting occlusion of carotid and vertebral arteries. Context and purpose: Our study was undertaken to observe and compare the morphology of circle of Willis using two entirely different methods; gross dissection (GD and Magnetic resonance angiography (MRA and to correlate the variant patterns encountered with the possible underlying developmental events. Gross dissection was carried out in 70 human cadavers and equal numbers of MRA’s of healthy individuals were studied retrospectively. Results: Only 31 cases (22.14% presented with a complete circle of Willis, out of which 14 (20% were cadaveric specimen and 17 (24.18% were in MRA group. Unilateral hypoplastic posterior communicating artery was the most common variation observed in our study (19.28%. Conclusions: The wide variation in completeness of the circle of Willis in general population is similar to earlier observations. Review of phylogeny and embryology makes us familiar with variant forms which would be otherwise difficult to recognize and may be misinterpreted. MRA and gross dissection findings despite certain variations are comparable.

  16. The use of magnetic resonance and MR angiography in the detection of cerebral infarction: A complication of pediatric bacterial meningitis

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    Stošić-Opinćal Tatjana

    2005-01-01

    Full Text Available Bacground. Association of both cerebral infarction and acute bacterial meningitis is more common in younger patients than in the elderly. The rate of mortality and the frequency of sequel are very high inspite of the use of modern antibiotic therapy. In more than 30% of the cases of childhood bacterial meningitis, both arterial and venous infarctions can occur. The aim of this study was to present the role of the use of magnetic resonance (MRI, and MR angiography (MRA in the detection of bacterial meningitis in children complicated with cerebral infarctions. Method. In the Centre for MR, the Clinical Centre of Serbia, 25 patients with the diagnosis of bacterial meningitis, of which 9 children with cerebral infarction whose clinical conditon deteriorated acutely, despite the antibiotic therapy, underwent MRI and MR angiography examination on a 1T scanner. Examination included the conventional spin-echo techniques with T1-weighted saggital and coronal, and T2- weighted axial and coronal images. Coronal fluid attenuated inversion recovery (FLAIR and the postcontrast T1-weighted images in three orthogonal planes were also used. The use MR angiography was accomplished by the three-dimensional time-of-flight (3D TOF technique. Results. The findings included: multiple hemorrhagic infarction in 4 patients, multiple infarctions in 3 patients, focal infarction in 1 patient and diffuse infarction (1 patient. Common sites of involvement were: the frontal lobes, temporal lobes and basal ganglia. The majority of infarctions were bilateral. In 3 of the patients empyema was found, and in 1 patient bitemporal abscess was detected. In 8 of the patients MR angiography confirmed inflammatory vasculitis. Conclusion. Infarction is the most common sequel of severe meningitis in children. Since the complication of cerebral infarction influences the prognosis of meningitis, repetitive MRI examinations are very significant for the evaluation of the time course of

  17. Common carotid intima media thickness and ankle-brachial pressure index correlate with local but not global atheroma burden: a cross sectional study using whole body magnetic resonance angiography.

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    Jonathan R Weir-McCall

    Full Text Available Common carotid intima media thickness (CIMT and ankle brachial pressure index (ABPI are used as surrogate marker of atherosclerosis, and have been shown to correlate with arterial stiffness, however their correlation with global atherosclerotic burden has not been previously assessed. We compare CIMT and ABPI with atheroma burden as measured by whole body magnetic resonance angiography (WB-MRA.50 patients with symptomatic peripheral arterial disease were recruited. CIMT was measured using ultrasound while rest and exercise ABPI were performed. WB-MRA was performed in a 1.5T MRI scanner using 4 volume acquisitions with a divided dose of intravenous gadolinium gadoterate meglumine (Dotarem, Guerbet, FR. The WB-MRA data was divided into 31 anatomical arterial segments with each scored according to degree of luminal narrowing: 0 = normal, 1 = <50%, 2 = 50-70%, 3 = 70-99%, 4 = vessel occlusion. The segment scores were summed and from this a standardized atheroma score was calculated.The atherosclerotic burden was high with a standardised atheroma score of 39.5±11. Common CIMT showed a positive correlation with the whole body atheroma score (β 0.32, p = 0.045, however this was due to its strong correlation with the neck and thoracic segments (β 0.42 p = 0.01 with no correlation with the rest of the body. ABPI correlated with the whole body atheroma score (β -0.39, p = 0.012, which was due to a strong correlation with the ilio-femoral vessels with no correlation with the thoracic or neck vessels. On multiple linear regression, no correlation between CIMT and global atheroma burden was present (β 0.13 p = 0.45, while the correlation between ABPI and atheroma burden persisted (β -0.45 p = 0.005.ABPI but not CIMT correlates with global atheroma burden as measured by whole body contrast enhanced magnetic resonance angiography in a population with symptomatic peripheral arterial disease. However this is

  18. Image Quality and Stenosis Assessment of Non-Contrast-Enhanced 3-T Magnetic Resonance Angiography in Patients with Peripheral Artery Disease Compared with Contrast-Enhanced Magnetic Resonance Angiography and Digital Subtraction Angiography.

    Science.gov (United States)

    Liu, Jiayi; Zhang, Nan; Fan, Zhaoyang; Luo, Nan; Zhao, Yike; Bi, Xiaoming; An, Jing; Chen, Zhong; Liu, Dongting; Wen, Zhaoying; Fan, Zhanming; Li, Debiao

    2016-01-01

    To evaluate the diagnostic performance of flow-sensitive dephasing (FSD)-prepared steady-state free precession (SSFP) magnetic resonance angiography (MRA) at 3 T for imaging infragenual arteries relative to contrast-enhanced MRA (CE-MRA) and digital subtraction angiography (DSA). A series of 16 consecutive patients with peripheral arterial disease (PAD) underwent a combined peripheral MRA protocol consisting of FSD-MRA for the calves and large field-of-view CE-MRA. DSA was performed on all patients within 1 week of the MR angiographies. Image quality and degree of stenosis was assessed by two readers with rich experience. Inter-observer agreement was determined using kappa statistics. Receiver operating characteristic (ROC) curve analysis determined the diagnostic value of FSD-MRA, CE-MRA, and CE-MRA combined with FSD-MRA (CE+FSD MRA) in predicting vascular stenosis. At the calf station, no significantly difference of subjective image quality scores was found between FSD-MRA and CE-MRA. Inter-reader agreement was excellent for both FSD-MRA and CE-MRA. Both of FSD-MRA and CE-MRA carry a stenosis overestimation risk relative to DSA standard. With DSA as the reference standard, ROC curve analysis showed that the area under the curve was largest for CE+FSD MRA. The greatest sensitivity and specificity were obtained when a cut-off stenosis score of 2 was used. In patients with severe PAD,3 T FSD-MRA provides good-quality diagnostic images without a contrast agent and is a good supplement for CE-MRA. CE+FSD MRA can improve the accuracy of vascular stenosis diagnosis.

  19. Magnetic resonance angiography signal intensity as a marker of hemodynamic impairment in intracranial arterial stenosis.

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    Xinyi Leng

    Full Text Available BACKGROUND: Intracranial arterial stenosis (ICAS is the predominant cause of ischemic stroke and transient ischemic attack in Asia. Change of signal intensities (SI across an ICAS on magnetic resonance angiography (MRA may reflect its hemodynamic severity. METHODS: In-patients with a symptomatic single ICAS detected on 3D time-of-flight MRA were recruited from 2 hospitals. Baseline and 1-year follow-up data were collected. Signal intensity ratio (SIR [ =  (mean post-stenotic SI -mean background SI/(mean pre-stenotic SI - mean background SI] was evaluated on baseline MRA to represent change of SIs across an ICAS. Acute infarct volume was measured on baseline diffusion-weighted images (DWI. Relationships between SIR and baseline characteristics as well as 1y outcomes were evaluated. RESULTS: Thirty-six subjects (86.1% males, mean age 55.0 were recruited. Overall, mean SIR was 0.84±0.23. Mean SIRs were not significantly different between the 23 (63.9% anatomically severe stenoses and the 13 (36.1% anatomically moderate stenoses (0.80±0.23 versus 0.92±0.21, p = 0.126. SIR was significantly, linearly and negatively correlated to acute infarct volume on DWI (Spearman correlation coefficient -0.471, p = 0.011. Two patients (5.6% had recurrent ischemic strokes at 1y, not related to SIR values. CONCLUSIONS: Change of signal intensities across an ICAS on MRA may reflect its hemodynamic and functional severity. Future studies are warranted to further verify the relationships between this index and prognosis of patients with symptomatic ICAS.

  20. Vessel segmentation in 4D arterial spin labeling magnetic resonance angiography images of the brain

    Science.gov (United States)

    Phellan, Renzo; Lindner, Thomas; Falcão, Alexandre X.; Forkert, Nils D.

    2017-03-01

    4D arterial spin labeling magnetic resonance angiography (4D ASL MRA) is a non-invasive and safe modality for cerebrovascular imaging procedures. It uses the patient's magnetically labeled blood as intrinsic contrast agent, so that no external contrast media is required. It provides important 3D structure and blood flow information but a sufficient cerebrovascular segmentation is important since it can help clinicians to analyze and diagnose vascular diseases faster, and with higher confidence as compared to simple visual rating of raw ASL MRA images. This work presents a new method for automatic cerebrovascular segmentation in 4D ASL MRA images of the brain. In this process images are denoised, corresponding image label/control image pairs of the 4D ASL MRA sequences are subtracted, and temporal intensity averaging is used to generate a static representation of the vascular system. After that, sets of vessel and background seeds are extracted and provided as input for the image foresting transform algorithm to segment the vascular system. Four 4D ASL MRA datasets of the brain arteries of healthy subjects and corresponding time-of-flight (TOF) MRA images were available for this preliminary study. For evaluation of the segmentation results of the proposed method, the cerebrovascular system was automatically segmented in the high-resolution TOF MRA images using a validated algorithm and the segmentation results were registered to the 4D ASL datasets. Corresponding segmentation pairs were compared using the Dice similarity coefficient (DSC). On average, a DSC of 0.9025 was achieved, indicating that vessels can be extracted successfully from 4D ASL MRA datasets by the proposed segmentation method.

  1. Catheter Angiography

    Medline Plus

    Full Text Available ... using: x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) In catheter angiography, a thin plastic tube, ... blood flow to the brain and cause a stroke. identify a small aneurysm or arteriovenous malformation (abnormal ...

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

    Science.gov (United States)

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

    2004-08-01

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

  3. Efficacy of magnetic resonance coronary angiography for evaluating coronary arterial lesions due to Kawasaki disease

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, Rikako; Suzuki, Atsuko; Sato, Katsuhiko; Ono, Masae; Hosina, Kiyoshi; Furuyama, Tamio; Takemura, Atsusi; Korenaga, Tateo [Tokyo Teishin Hospital (Japan)

    2002-11-01

    To reduce the number of invasive X-ray coronary angiography (XCA) in patients with coronary arterial lesions (CAL) due to Kawasaki disease, we evaluated the efficacy of noninvasive magnetic resonance coronary angiography (MRCA). We preformed MRCA on 30 patients with Kawasaki disease (age 4 months to 37 years; medium 9 years) by SIEMENS MAGNETOM Symphony 1.5 T. MRCA with free respiration using navigator echo 3D fast low angle shot (3D-FLASH) was performed on 10 young children. Evaluation of MRCA was based on the findings of 2D echo cardiogram (30 patients) and XCA (14 patients). All 17 aneurysms (100%) were detected by MRCA; four out of five dilatations were detected by MRCA (80%), but a slight dilatation was not detected (i.e., appeared to be a normal coronary artery). We observed seven stenoses (100%) that were detected on XCA and one new stenosis on MRCA; both of two aortocoronary bypass graphs (one in each of two patients; 100%) were observed to be patent. These results demonstrated that MRCA was highly beneficial, first for detecting CAL after the acute phase even in young infants, second for reducing the number of XCA examination times for following up CAL, and third for screening of CAL in adults with a history of Kawasaki disease. (author)

  4. Computer simulation of magnetic resonance angiography imaging: model description and validation.

    Directory of Open Access Journals (Sweden)

    Artur Klepaczko

    Full Text Available With the development of medical imaging modalities and image processing algorithms, there arises a need for methods of their comprehensive quantitative evaluation. In particular, this concerns the algorithms for vessel tracking and segmentation in magnetic resonance angiography images. The problem can be approached by using synthetic images, where true geometry of vessels is known. This paper presents a framework for computer modeling of MRA imaging and the results of its validation. A new model incorporates blood flow simulation within MR signal computation kernel. The proposed solution is unique, especially with respect to the interface between flow and image formation processes. Furthermore it utilizes the concept of particle tracing. The particles reflect the flow of fluid they are immersed in and they are assigned magnetization vectors with temporal evolution controlled by MR physics. Such an approach ensures flexibility as the designed simulator is able to reconstruct flow profiles of any type. The proposed model is validated in a series of experiments with physical and digital flow phantoms. The synthesized 3D images contain various features (including artifacts characteristic for the time-of-flight protocol and exhibit remarkable correlation with the data acquired in a real MR scanner. The obtained results support the primary goal of the conducted research, i.e. establishing a reference technique for a quantified validation of MR angiography image processing algorithms.

  5. Hemodynamic Change in Pulmonary Vein Stenosis after Radiofrequency Ablation: Assessment with Magnetic Resonance Angiography

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    Yun, Doyoung; Jung, Jung Im; Oh, Yong Seog; Youn, Ho Joong [Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of)

    2012-11-15

    We present a case of pulmonary vein (PV) stenosis after radio-frequency (RF) ablation, in which a hemodynamic change in the pulmonary artery was similar to that of congenital PV atresia on time-resolved contrast-enhanced magnetic resonance angiography (TR-MRA). A 48-year-old man underwent RF ablation due to atrial fibrillation. The patient subsequently complained of hemoptysis, dyspnea on exertion, and right chest pain. Right PV stenosis after catheter ablation was diagnosed through chest computed tomography and lung perfusion scan. Pulmonary TR-MRA revealed the pulmonary artery via systemic arterial collaterals and draining systemic collateral veins. On a velocity-encoded cine image, the flow direction of the right pulmonary artery was reversed in the diastolic phase and the left pulmonary artery demonstrated continuous forward flow throughout the cardiac cycle. These hemodynamic changes were similar to those seen in congenital unilateral PV atresia.

  6. Intracranial Aneurysms Treated with Coil Placement: Test Characteristics of Follow-up MR Angiography-Multicenter Study

    NARCIS (Netherlands)

    J.D. Schaafsma; B.K. Velthuis; C.B.L.M. Majoie; R. van den Berg; P.A. Brouwer; F. Barkhof; O. Eshghi; G.A.P. de Kort; R.T.H. Lo; T.D. Witkamp; M.E.S. Sprengers; M.A. van Walderveen; J.C. Bot; E. Sanchez; W.P. Vandertop; J. van Gijn; E. Buskens; Y. van der Graaf; G.J.E. Rinkel

    2010-01-01

    Purpose: To determine the test characteristics of magnetic resonance (MR) angiography in the assessment of occlusion of aneurysms treated with coil placement. Materials and Methods: This was an ethics committee-approved multicenter study. Written informed consent was obtained in 311 patients with 34

  7. Diagnostic Pitfalls in Postinterventional Intraarterial Magnetic Resonance Angiography after Recanalization of Femoropopliteal Arterial Occlusions

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    Huegli, R.W.; Aschwanden, M.; Kos, S.; Rasmus, M.; Jaeger, K.; Jacob, A.L.; Bilecen, D. (Dept. of Radiology and Dept. of Angiology, Univ. Hospital of Basel, Basel (Switzerland))

    2008-12-15

    Background: Magnetic resonance (MR)-guided vascular interventions are of increasing interest, and, with the use of contrast-enhanced techniques, intraarterial contrast-enhanced MR angiography (ia-ce-MRA) competes with intraarterial digital subtraction angiography (ia-DSA) for the diagnostic evaluation of the infrainguinal vessel tree. Purpose: To assess the diagnostic value of ia-ce-MRA and high-resolution T1-weighted (hr-T1w) imaging compared to the gold-standard ia-DSA for residual stenosis and local dissections after femoropopliteal recanalization in patients with peripheral arterial occlusive disease (PAOD). Material and Methods: Eight patients with PAOD and short vessel occlusion of their femoropopliteal arteries underwent recanalization and balloon positioning under DSA. Patients were transferred to a short-bore MR scanner. Percutaneous transluminal angioplasty (PTA) was accomplished under MR fluoroscopy. Pre- and postinterventional ia-ce three-dimensional (3D) gradient-echo MRA with gadopentate dimeglumine was performed using the intraarterial introducer sheath. Maximum intensity projections (MIP) and multiplanar reconstructions (MPR) were calculated from the data set. High-resolution T1w images of the angioplasty region before and after dilatation were acquired. Control ia-DSA images were obtained. Results: The postinterventional angioplasty results for stenosis grading were comparable in ia-MRA and ia-DSA. Only two of five local dissections in ia-DSA were visualized with the ia-ce-MRA runs including MIPs and MPRs. To clearly depict dissection, hr-T1w images were needed. Conclusion: Grading of stenotic lesions with ia-ce-MRA after PTA is comparable to ia-DSA. Intraarterial ce-MRA with calculated MIPs and MPRs is only partially sufficient to visualize local dissections after PTA. High-resolution T1w images are required for precise diagnosis of dissections in magnetic resonance tomography

  8. Diagnostic Pitfalls in Postinterventional Intraarterial Magnetic Resonance Angiography after Recanalization of Femoropopliteal Arterial Occlusions

    Energy Technology Data Exchange (ETDEWEB)

    Huegli, R.W.; Aschwanden, M.; Kos, S.; Rasmus, M.; Jaeger, K.; Jacob, A.L.; Bilecen, D. [Dept. of Radiology and Dept. of Angiology, Univ. Hospital of Basel, Basel (Switzerland)

    2008-12-15

    Background: Magnetic resonance (MR)-guided vascular interventions are of increasing interest, and, with the use of contrast-enhanced techniques, intraarterial contrast-enhanced MR angiography (ia-ce-MRA) competes with intraarterial digital subtraction angiography (ia-DSA) for the diagnostic evaluation of the infrainguinal vessel tree. Purpose: To assess the diagnostic value of ia-ce-MRA and high-resolution T1-weighted (hr-T1w) imaging compared to the gold-standard ia-DSA for residual stenosis and local dissections after femoropopliteal recanalization in patients with peripheral arterial occlusive disease (PAOD). Material and Methods: Eight patients with PAOD and short vessel occlusion of their femoropopliteal arteries underwent recanalization and balloon positioning under DSA. Patients were transferred to a short-bore MR scanner. Percutaneous transluminal angioplasty (PTA) was accomplished under MR fluoroscopy. Pre- and postinterventional ia-ce three-dimensional (3D) gradient-echo MRA with gadopentate dimeglumine was performed using the intraarterial introducer sheath. Maximum intensity projections (MIP) and multiplanar reconstructions (MPR) were calculated from the data set. High-resolution T1w images of the angioplasty region before and after dilatation were acquired. Control ia-DSA images were obtained. Results: The postinterventional angioplasty results for stenosis grading were comparable in ia-MRA and ia-DSA. Only two of five local dissections in ia-DSA were visualized with the ia-ce-MRA runs including MIPs and MPRs. To clearly depict dissection, hr-T1w images were needed. Conclusion: Grading of stenotic lesions with ia-ce-MRA after PTA is comparable to ia-DSA. Intraarterial ce-MRA with calculated MIPs and MPRs is only partially sufficient to visualize local dissections after PTA. High-resolution T1w images are required for precise diagnosis of dissections in magnetic resonance tomography.

  9. 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.

  10. The added value of longitudinal black-blood cardiovascular magnetic resonance angiography in the cross sectional identification of carotid atherosclerotic ulceration

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    Hippe Daniel S

    2009-08-01

    Full Text Available Abstract Background Carotid atherosclerotic ulceration is a significant source of stroke. This study evaluates the efficacy of adding longitudinal black-blood (BB cardiovascular magnetic resonance (CMR angiography to cross-sectional CMR images in the identification of carotid atherosclerotic ulceration. Methods Thirty-two subjects (30 males and two females with ages between 48 and 83 years scheduled for carotid endarterectomy were imaged on a 1.5T GE Signa scanner using multisequence [3D time-of-flight, T1, proton density, T2, contrast enhanced T1], cross-sectional CMR images and longitudinal BB CMR angiography (0.625 × 0.625 mm/pixel. Two rounds of review (round 1: cross-sectional CMR images alone and round 2: cross-sectional CMR images plus longitudinal BB CMR angiography were conducted for the presence and volume measurements of ulceration. Ulceration was defined as a distinct depression into the plaque containing blood flow signal on cross-sectional CMR and longitudinal BB CMR angiography. Results Of the 32 plaques examined by histology, 17 contained 21 ulcers. Using the longitudinal BB CMR angiography sequence in addition to the cross-sectional CMR images in round 2, the sensitivity improved to 80% for ulcers of at least 6 mm3 in volume by histology and 52.4% for all ulcers, compared to 30% and 23.8% in round 1, respectively. There was a slight decline in specificity from 88.2% to 82.3%, though both the positive and negative predictive values increased modestly from 71.4% to 78.6% and from 48.4% to 58.3%, respectively. Conclusion The addition of longitudinal BB CMR angiography to multisequence cross-sectional CMR images increases accuracy in the identification of carotid atherosclerotic ulceration.

  11. A follow-up study of autosomal dominant polycystic kidney disease with intracranial aneurysms using 3.0 T three-dimensional time-of-flight magnetic resonance angiography

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    Jiang, Tao; Wang, Peng; Qian, Yi [Department of Radiology, Changzheng Hospital, Second Military Medical University, Shanghai (China); Zheng, Xuan [Clinical Nutrition Department of Changhai Hospital, Second Military Medical University, Shanghai (China); Xiao, Liaoyuan [Department of Nephrology, Changzheng Hospital, Second Military Medical University, Shanghai (China); Yu, Shengqiang, E-mail: yushengqiang_cz@163.com [Department of Nephrology, Changzheng Hospital, Second Military Medical University, Shanghai (China); Liu, Shiyuan, E-mail: laijiangtaotao@163.com [Department of Radiology, Changzheng Hospital, Second Military Medical University, Shanghai (China)

    2013-11-01

    Objective: Autosomal dominant polycystic kidney disease (ADPKD) patients have an increased risk for intracranial aneurysms (IAs). Our aim was to screen and follow up the unruptured intracranial aneurysms (UIAs) detected by 3.0 T three-dimensional time-of-flight magnetic resonance angiography (3D-TOF MRA) in patients with ADPKD in order to evaluate the growth of UIAs and the value of 3D-TOF MRA. Methods: From 2011 to 2012, we followed up UIAs detected in 40 ADPKD patients who had MRA examinations with an interval of at least 36 months. All MRA examinations were performed on a 3 T system (Achieva X-Series, Philips Medical Systems) with a Sense-Head-8 receiver head coil. The acquired data sets were transferred to a workstation (EWS, Philips Medical) to perform maximum intensity projection (MIP) and volume rendering (VR) with a specialized software package (Philips Medical). The size of UIAs was determined as the longest diameter in transverse or vertical measurement. UIAs that grew more than 20% were considered as enlarged. Results: Fifty UIAs were found in 40 previously examined ADPKD patients who underwent 3.0 T 3D-TOF MRA follow-ups. No patients ever had treatment before the second examination. The longest diameter of all follow-up UIAs was less than 10 mm and mean diameter was 3.64 ± 2.25 mm. UIAs in only 4 patients (10%) were considered as enlarged. None of the 50 IAs in the 40 ADPKD patients ruptured during the MRA follow-up period. Conclusion: 3.0 T 3D-TOF MRA was feasible for UIAs follow-up in ADPKD patients. The chance of enlargement and rupture of UIAs in ADPKD patients was not higher than in the general population.

  12. Prospective intraindividual comparison of gadoterate and gadobutrol for cervical and intracranial contrast-enhanced magnetic resonance angiography.

    Science.gov (United States)

    Hoelter, Philip; Lang, Stefan; Weibart, Marina; Schmidt, Manuel; Knott, Michael F X; Engelhorn, Tobias; Essig, Marco; Kloska, Stephan; Doerfler, Arnd

    2017-09-14

    Gadobutrol (GB) is reported to provide improved relaxivity and concentration compared to gadoterate (GT). This study was designed to intraindividually compare quantitative and qualitative enhancement characteristics of GB to GT in cervicocranial magnetic resonance angiography (MRA) of patients with cerebrovascular disease (CVD). Patients (n = 54) with CVD underwent two identical contrast-enhanced magnetic resonance angiography (CE-MRA) examinations of the cervical and intracranial vasculature in randomized order, using GB and GT in equimolar dose. Signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were obtained by two independent neuroradiologists, blinded to the applied contrast agents. Qualitative assessment was performed using a three-point scale with a focus on M1/M2 segments. One thousand and twenty-six vessel segments were analyzed. GB revealed a significantly higher SNR (p = 0.032) and CNR (p = 0.031) in all vessel segments. GB featured a significantly higher SNR and CNR in thoracic (p = 0.022; p = 0.016) and cervical vessels (p = 0.03; p = 0.038), as well as in the posterior circulation (p = 0.012; p = 0.005). In blinded qualitative assessment, overall preference was given to GB (p = 0.02), showing a significant better delineation of the M1/M2 segments (p = 0.041). Compared to GT, the use of GB results in a significantly higher SNR and CNR in cervical and cerebral CE-MRA, leading to a better delineation of the intracranial vasculature. Present results underline the potential of GB for improved CE-MRA assessment of vasculature in CVD patients.

  13. Dixon-type and subtraction-type contrast-enhanced magnetic resonance angiography: A theoretical and experimental comparison of SNR and CNR.

    Science.gov (United States)

    Stinson, Eric G; Trzasko, Joshua D; Weavers, Paul T; Riederer, Stephen J

    2014-07-17

    The purpose of this work is to compare the behavior of the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in contrast-enhanced MR angiography with background suppression performed by either a Dixon-type or subtraction-type method. Theoretical expressions for the SNR and CNR for both background suppression techniques were derived. The theoretical Dixon:subtraction SNR and CNR ratios were compared to empirical ratios measured from phantom and in vivo studies for Dixon techniques utilizing one, two, and three echoes. Specifically, the SNR and CNR ratios were compared as the concentration of contrast material in the blood changed. Empirical measurements of the SNR and CNR ratios compared favorably with the ratios predicted by theory. As the contrast concentration was reduced, the SNR advantage of the Dixon techniques increased asymptotically. In the ideal case, the SNR improvement over subtraction contrast-enhanced MR angiography was at least twofold for one- and two-echo Dixon techniques and at least a factor of 6 for the three-echo Dixon technique. Expressions showing a contrast concentration-dependent SNR and CNR improvement of at least a factor of two when Dixon-type contrast-enhanced MR angiography is used in place of subtraction-type contrast-enhanced MR angiography were derived and validated with phantom and in vivo experiments. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc. Copyright © 2014 Wiley Periodicals, Inc.

  14. PEGylated silica nanoparticles encapsulating multiple magnetite nanocrystals for high-performance microscopic magnetic resonance angiography.

    Science.gov (United States)

    Wu, Si-Han; Lin, Chien-Yuan; Hung, Yann; Chen, Wei; Chang, Chen; Mou, Chung-Yuan

    2011-10-01

    A novel magnetic resonance (MR) angiographic method, 3DΔR2-mMRA (three dimensional and ΔR2 based microscopy magnetic resonance angiography), is developed as a clinical diagnosis for depicting the function and structure of cerebral small vessels. However, the visibility of microvasculatures and the precision of cerebral blood volume calculation greatly rely on the transverse relaxivity and intravascular half-life of contrast agent, respectively. In this work, we report a blood pool contrast agent named H-Fe₃O₄@SiO₂-PEG where multiple Fe₃O₄ nanocrystals are encapsulated in a thin silica shell to enhance the T₂-relaxivity (r₂ = 342.8 mM⁻¹ s⁻¹) and poly(ethylene glycol) (PEG) is employed to reduce opsonization and prolong circulation time of nanoparticles. Utilization of the newly developed H-Fe₃O₄@SiO₂-PEG with a novel MR angiographic methodology, a high-resolution MR image of rat cerebral microvasculatures is successfully obtained.

  15. Spontaneous arterial recanalization with magnetic resonance angiography evidence: report of a case.

    Science.gov (United States)

    Filis, Konstantinos A; Arko, Frank R; Bakoyannis, Chris N; Georgopoulos, Sotiris E; Bramis, John; Bastounis, Elias A

    2006-01-01

    A 27-year-old man was admitted to our hospital for investigation of severe claudication in his right foot. Based on the findings of magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA), we diagnosed anatomic popliteal artery entrapment syndrome, which was causing a short popliteal artery occlusion. Moreover, a long posterior tibial artery occlusion and a peroneal artery lesion had developed as distal thromboembolic complications of the entrapment. Thus, we planned to perform in situ vein bypass graft for the popliteal occlusion and start thrombolytic treatment for the posterior tibial and peroneal lesions. While contemplating the operation, the patient showed a gradual clinical improvement over the next 2 months. A second MRA showed total arterial recanalization of the right posterior tibial and peroneal arteries, although the popliteal artery was still occluded. Spontaneous lower limb arterial recanalization is a rare phenomenon. To our knowledge, this is the first case of spontaneous arterial recanalization after a distal thromboembolic event caused by popliteal entrapment syndrome.

  16. Technical inadequacies of peripheral contrast-enhanced magnetic resonance angiography: incidence, causes and management strategies

    Energy Technology Data Exchange (ETDEWEB)

    Low, G. [Department of Radiology, Hairmyres Hospital, East Kilbride (United Kingdom); Mizzi, A. [Department of Radiology, Hairmyres Hospital, East Kilbride (United Kingdom)]. E-mail: adrianmizzi@yahoo.co.uk; Ong, K. [Department of Radiology, Hairmyres Hospital, East Kilbride (United Kingdom); Lau, P.F. [Department of Radiology, Hairmyres Hospital, East Kilbride (United Kingdom); McKinstery, J. [Department of Radiology, Hairmyres Hospital, East Kilbride (United Kingdom)

    2006-11-15

    Aim: To assess the incidence, causes and effects of technical inadequacies in peripheral contrast-enhanced magnetic resonance angiography (CE-MRA) and to discuss relevant management strategies. Materials and methods: A retrospective analysis of 249 peripheral CE-MRA examinations was performed using the radiology department's RIS/PACS (radiology information system/picture archiving and communication system) database. All failed or technically inadequate MRAs were reviewed. In cases that underwent further imaging by conventional angiography (CA), we assessed if relevant arterial disease had been masked on the MRA. Results: Of the 249 examinations, 215 (86.3%) were technically satisfactory while 34 (13.7%) were a combination of technical inadequacies [29 cases (11.6%)] and examination failures [five cases (2%)]. The causes of technical inadequacies were: (1) venous contamination (13 cases; 5.2%), (2) motion-induced subtraction artefact (eight cases; 3.2%), (3) stent-induced artefact (four cases; 1.6%), (4) inadequate scan coverage (two cases; 0.8%), and (5) contrast timing error (two cases; 0.8%). The causes of failed examinations were: (1) inability to tolerate lying in the scanner (three cases; 1.2%) and (2) inability to fit into the scanner (two cases; 0.8%). Fifteen (44.1%) of the 34 cases underwent further imaging by CA, and in eight of these there was significant arterial disease that was missed on the MRA. Conclusion: Technical inadequacies occur in a small but significant proportion of peripheral CE-MRAs and can mask significant arterial disease. Knowledge of the potential causes of technical problems and the relevant management options is important for quality assurance and for limiting the need for an alternative investigation.

  17. Magnetic resonance angiography in the evaluation of renal arteries: imaging findings; Angiografia por ressonancia magnetica na avaliacao das arterias renais: achados de imagem

    Energy Technology Data Exchange (ETDEWEB)

    Nacif, Marcelo Souto [Faculdade de Medicina de Teresopolis, RJ (Brazil). Curso de Radiologia]. E-mail: msnacif@yahoo.com.br; Santos, Alair Augusto Sarmet Moreira Damas dos [Instituto de Pos-graduacao Medica Carlos Chagas (VOT-Imagem), Rio de Janeiro, RJ (Brazil). Curso de Especializacao em Radiologia; Marchiori, Edson [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Radiologia]. E-mail: msnacif@yahoo.com.br

    2006-07-15

    Objective: to describe indications, main findings and diagnosis of magnetic resonance angiographies of renal arteries. Materials and methods: a retrospective study including 56 imaging studies covering a total of 111 renal arteries, performed during the period between December 6, 2001 and March 11, 2004. The angiographies were performed in a 1.5 T scanner, in compliance with the Department protocol. Results: as regards sex, it was found that 55.4% (n = 31) patients were male and 44.6% (n = 25) were female. The youngest patient was 12 years old and the oldest 88 years old. From a total of 25 different clinical indications, systemic arterial hypertension was the principal one with 26.7% (n = 15), followed by abdominal and/or lumbar pain with 12.5% (n 7), abdominal aortic aneurysm with 10.7% (n = 6), renal artery stenosis with 8.9% (n = 5), and others. Among these 56 studies, 43 (76.7%) had different types of findings and 13 (23.2%) were normal. The majority of findings were related to vascular diameter and amongst them, parietal irregularities, aneurysms and stenosis were the most frequent. Parietal irregularity was the most frequent alteration in the right renal artery with 17.87% (n = 10) and stenosis, in the left renal artery, with 25.45% (n = 14). Conclusion: magnetic resonance angiography has shown to be an excellent non-invasive method for evaluation of renal arteries, because of its sensitivity and multiplanar capacity for demonstrating vascular structures. (author)

  18. Posterior cerebral artery laterality on magnetic resonance angiography predicts long-term functional outcome in middle cerebral artery occlusion.

    Science.gov (United States)

    Ichijo, Masahiko; Miki, Kazunori; Ishibashi, Satoru; Tomita, Makoto; Kamata, Tomoyuki; Fujigasaki, Hiroto; Mizusawa, Hidehiro

    2013-02-01

    Prominent posterior cerebral artery (PCA) laterality upon 3-dimensional time-of-flight magnetic resonance angiography is often encountered in patients with middle cerebral artery occlusion. We hypothesized that this sign is correlated with improved functional outcome in patients with middle cerebral artery occlusion treated with intravenous recombinant tissue plasminogen activator. Fifty acute ischemic stroke patients with middle cerebral artery occlusion were treated with intravenous recombinant tissue plasminogen activator from April 2007 to October 2009. All patients routinely underwent initial (first 3 hours) magnetic resonance scans on admission, and additional follow-up (14-21 days after stroke onset) computed tomography scans. Two film readers blinded to all clinical information assessed the presence or absence of PCA laterality on magnetic resonance angiography. We retrospectively analyzed the clinical and radiologic data on all patients. Out of 50 patients, 20 showed PCA laterality on magnetic resonance angiography. National Institute of Health Stroke Scale score 7 days after stroke onset was significantly lower (P=0.007), and infarct volume on follow-up computed tomography was significantly smaller (P=0.009) in patients with PCA laterality than in patients without this sign. Multivariate logistic regression analyses showed an adjusted odds ratio of 8.49 for a favorable outcome (modified Rankin Scale score 0-1 at 6 months) in patients with PCA laterality (95% CI: 1.82 to 55.8, P=0.005). The presence of PCA laterality on magnetic resonance angiography before intravenous recombinant tissue plasminogen activator can be used as a predictor of favorable functional outcome in patients with middle cerebral artery occlusion, probably due to improvement of recanalization rate.

  19. Complications after liver transplantation: evaluation with magnetic resonance imaging, magnetic resonance cholangiography, and 3-dimensional contrast-enhanced magnetic resonance angiography in a single session

    Energy Technology Data Exchange (ETDEWEB)

    Boraschi, P.; Donati, F.; Gigoni, R. [Pisa Univ. Hospital, Second Dept. of Radiology, Pisa (Italy)], E-mail: p.boraschi@do.med.unipi.it; Salemi, S. [Univ. of Pisa, Diagnostic and Interventional Radiology, Pisa (Italy); Urbani, L.; Filipponi, F. [Univ. of Pisa, Liver Transplant Unit of the Dept. of Oncology, Transplants and Advanced Technologies in Medicine, Pisa (Italy); Falaschi, F. [Pisa Univ. Hospital, Second Dept. of Radiology, Pisa (Italy); Bartolozzi, C. [Univ. of Pisa, Diagnostic and Interventional Radiology, Pisa (Italy)

    2008-12-15

    To evaluate a comprehensive magnetic resonance imaging (MRI) protocol as noninvasive diagnostic modality for simultaneous detection of parenchymal, biliary, and vascular complications after liver transplantation. Fifty-two liver transplant recipients suspected to have parenchymal, biliary, and (or) vascular complications underwent our MRI protocol at 1.5T unit using a phased array coil. After preliminary acquisition of axial T{sub 1}w and T{sub 2}w sequences, magnetic resonance cholangiography (MRC) was performed through a breath-hold, thin- and thick-slab, single-shot T{sub 2}w sequence in the coronal plane. Contrast-enhanced magnetic resonance angiography (CEMRA) was obtained using a 3-dimensional coronal spoiled gradient-echo sequence, which enabled acquisition of 32 partitions 2.0 mm thick. A fixed dose of 20 ml gadobenate dimeglumine was administered at 2 mL/s. A post-contrast T{sub 1}w sequence was also performed. Two observers in conference reviewed source images and 3-dimensional reconstructions to determine the presence of parenchymal, biliary, and vascular complications. MRI findings were correlated with surgery, endoscopic retrograde cholangiography (ERC), biopsy, digital subtraction angiography (DSA), and imaging follow-up. MRI revealed abnormal findings in 32 out of 52 patients (61%), including biliary complications (anastomotic and nonanastomotic strictures, and lithiasis) in 31, vascular disease (hepatic artery stenosis and thrombosis) in 9, and evidence of hepatic abscess and hematoma in 2. ERC confirmed findings of MRC in 30 cases, but suggested disease underestimation in 2. DSA confirmed 7 magnetic resonance angiogram (MRA) findings, but suggested disease overestimation in 2. MRI combined with MRC and CEMRA can provide a comprehensive assessment of parenchymal, biliary, and vascular complications in most recipients of liver transplantation. (author)

  20. Breath-hold imaging of the coronary arteries using Quiescent-Interval Slice-Selective (QISS) magnetic resonance angiography: pilot study at 1.5 Tesla and 3 Tesla.

    Science.gov (United States)

    Edelman, Robert R; Giri, S; Pursnani, A; Botelho, M P F; Li, W; Koktzoglou, I

    2015-11-23

    Coronary magnetic resonance angiography (MRA) is usually obtained with a free-breathing navigator-gated 3D acquisition. Our aim was to develop an alternative breath-hold approach that would allow the coronary arteries to be evaluated in a much shorter time and without risk of degradation by respiratory motion artifacts. For this purpose, we implemented a breath-hold, non-contrast-enhanced, quiescent-interval slice-selective (QISS) 2D technique. Sequence performance was compared at 1.5 and 3 Tesla using both radial and Cartesian k-space trajectories. The left coronary circulation was imaged in six healthy subjects and two patients with coronary artery disease. Breath-hold QISS was compared with T2-prepared 2D balanced steady-state free-precession (bSSFP) and free-breathing, navigator-gated 3D bSSFP. Approximately 10 2.1-mm thick slices were acquired in a single ~20-s breath-hold using two-shot QISS. QISS contrast-to-noise ratio (CNR) was 1.5-fold higher at 3 Tesla than at 1.5 Tesla. Cartesian QISS provided the best coronary-to-myocardium CNR, whereas radial QISS provided the sharpest coronary images. QISS image quality exceeded that of free-breathing 3D coronary MRA with few artifacts at either field strength. Compared with T2-prepared 2D bSSFP, multi-slice capability was not restricted by the specific absorption rate at 3 Tesla and pericardial fluid signal was better suppressed. In addition to depicting the coronary arteries, QISS could image intra-cardiac structures, pericardium, and the aortic root in arbitrary slice orientations. Breath-hold QISS is a simple, versatile, and time-efficient method for coronary MRA that provides excellent image quality at both 1.5 and 3 Tesla. Image quality exceeded that of free-breathing, navigator-gated 3D MRA in a much shorter scan time. QISS also allowed rapid multi-slice bright-blood, diastolic phase imaging of the heart, which may have complementary value to multi-phase cine imaging. We conclude that, with further clinical

  1. Feasibility of magnetic resonance angiography (MRA) follow-up as the primary imaging modality after coiling of intracranial aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Bakker, Nicolaas A.; Metzemaekers, Jan D. M.; Dijk, J. Marc C. van; Mooij, Jan Jakob A.; Groen, Rob J. M. (Dept. of Neurosurgery, Univ. Medical Center Groningen, Univ. of Groningen, Groningen (Netherlands)), e-mail: r.j.m.groen@nchir.umcg.nl; Westerlaan, Henriette E.; Eshghi, Omid S. (Dept. of Radiology, Univ. Medical Center Groningen, Univ. of Groningen, Groningen (Netherlands))

    2010-03-15

    Background: Digital subtraction angiography (DSA) is still regarded as the gold standard for detecting residual flow in treated aneurysms. Recent reports have also shown excellent results from magnetic resonance angiography (MRA) imaging. This is an important observation, since DSA is associated with a risk of medical complications, is time consuming, and is more expensive. Purpose: To determine whether MRA could replace conventional DSA and serve as the primary postinterventional imaging modality in patients with coiled intracranial aneurysms. Material and Methods: We studied a prospectively enrolled cohort of 190 patients treated endovascularly for a first-ruptured and/or unruptured intracranial aneurysm between January 2004 and December 2008. The imaging protocol included a 1.5T time-of-flight (TOF) MRA and a DSA at 3 months (on the same day) and, depending on comparability, a 1.5T TOF-MRA or DSA 1 year after treatment. All images were evaluated by a multidisciplinary panel. Results: In 141/190 patients, both an MRA and DSA were performed after 3-month follow-up. In 2/141 patients (1.4%), (small) neck remnants gave false-negative MRA results. In one patient (0.7%), this led to additional neurosurgical clipping of the aneurysm. In 25/141 patients, future follow-up (>3 months) consisted of DSA because of various reasons. In 24/25 of these patients, primary MRA images alone would invariably have led to additional DSA imaging. Conclusion: The present study shows that 1.5T TOF-MRA is a feasible primary follow-up modality after coiling of intracranial aneurysms. Given our data, we now suggest that, in every patient with a coiled intracranial aneurysm, the first follow-up, 3 months after coiling, should be an MRA study. Only when this MRA is inconclusive (e.g., because of coil artifacts), or in the case of suspicion of recanalization, should DSA be performed additionally

  2. 3D FIESTA pulse sequence for assessing renal artery stenosis: is it a reliable application in unenhanced magnetic resonance angiography?

    Science.gov (United States)

    Gaudiano, Caterina; Busato, Fiorenza; Ferramosca, Emiliana; Cecchelli, Carlo; Corcioni, Beniamino; De Sanctis, Lucia Barbara; Santoro, Antonio; Golfieri, Rita

    2014-12-01

    To assess the capability of the three-dimensional (3D) Fast Imaging Employing Steady-State Acquisition (FIESTA) sequence in evaluating renal artery stenosis (RAS). We retrospectively analysed 79 patients referred for suspected RAS, examined by 3D FIESTA and contrast-enhanced magnetic resonance angiography (CE-MRA), using a 1.5T whole-body scanner. Image quality was assessed as well as the presence and grade of RAS. Patients with RAS ≥ 50% were evaluated for possible digital subtraction angiography (DSA). Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy of 3D FIESTA were calculated with ROC analysis using CE-MRA and DSA as the standard of reference. A total of 186 renal arteries were assessed; 36 had RAS ≥ 50 % demonstrated by CE-MRA. Ten patients underwent DSA, for a total evaluation of 22 arteries. Sensitivity, specificity, NPV, PPV, and accuracy of 3D FIESTA were 91.7%, 100%, 98%, 100%, and 98%, respectively, as compared to CE-MRA, and 88.2%, 100%, 71.4%, 100%, and 91%, respectively, as compared to DSA. The area under the ROC curve (AUC) of 3D FIESTA as compared to CE-MRA and DSA was 0.958 and 0.941, respectively. Our study demonstrated the capability of the 3D FIESTA sequence in evaluating RAS, with high-quality images and good diagnostic accuracy. The 3D FIESTA sequence provides a robust evaluation of RAS. The 3D FIESTA sequence allows non-invasive evaluation of the renal arteries. The 3D FIESTA sequence could be a useful tool in evaluating RAS.

  3. Diagnosis of systemic arterial diseases with whole-body 3D contrast-enhanced magnetic resonance angiography

    Institute of Scientific and Technical Information of China (English)

    LIN Jiang; CHEN Bin; WANG Jian-hua

    2006-01-01

    Background With the development of magnetic resonance (MR) technologies, whole-body 3D contrast-enhanced MR angiography (3D CE MRA) has become possible. The purpose of this study was to introduce and evaluate this technique in demonstration of various systemic arterial diseases.Methods Thirty-seven patients underwent whole-body 3D CE MRA using a 1.5T MR imager. The patients included were with clinically documented or suspected peripheral arterial occlusive disease (PAOD, n=19),Takayasu arteritis (n=8), polyarteritis nodosa (n=1), Type B dissection (n=4) and thoracic and/or abdominal aneurysm (n=5). Sixty-eight surface coil elements were employed to encompass the whole body. Four 3D CE MRA stations were acquired successively through automatic table moving. A total scan range of 188 cm,covering the arterial tree from carotid artery to trifurcation vessels, was acquired. Overall image quality of each arterial segment and venous overlay were assessed and rated. The depiction of various systemic arterial diseases was evaluated and compared with other imaging modalities if available, including digital subtraction angiography (DSA), CT angiography, dedicated mono-station MRA.Results Whole-body 3D CE MRA was well tolerated by all patients. It yielded a detailed display of the arterial system with a short examination time. The image quality was considered diagnostic in 99.3% of the arterial segments. The remaining 0.7% of the arterial segments were considered non-diagnostic. In 7 of 19 patients with PAOD, whole-body MRA showed additional vascular narrowing apart from peripheral arterial disease. In 9 patients with vasculitis, whole-body MRA depicted luminal irregularity, narrowing or occlusion, aneurysm and collateral circulation involving multiple vascular segments. Whole-body MRA also clearly revealed the severity and extent of dissection and aortic aneurysm. In 20 cases the vascular pathologies demonstrated on whole body MRA were confirmed by other imaging investigations

  4. Magnetic resonance imaging and magnetic resonance angiography in severe crush syndrome with consideration of fasciotomy or amputation: a novel diagnostic tool

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ling; FANG Zhi-jia; LIU Fang; FU Ping; TAO Ye; LI Zheng-yan; SONG Bin

    2011-01-01

    Three cases of severe crush syndrome after the Wenchuan earthquake in China are presented. The patients, 2 males and one female ranging in age from 18-45 years were studied via 1.5 T magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). MRI examinations were performed more than twice on two patients within 60 days of the earthquake. All the patients had acute renal failure (ARF) with plasma myoglobin concentrations above 17 000 μg/L The T2-weighted and short time inversion recovery (STIR) sequences revealed high intensity lesions in the affected muscles, and enhanced T1 -weighted images showed enhancement of partial affected muscles. MRA revealed no signs of arterial occlusion, arteriostenosis, or filling defects of main arteries. All patients were managed medically with continuous venous-venous hemofiltration and other supportive care, and none required fasciotomy or amputation. Repeat MR studies showed that the high intensity lesions seen on the T2-weighted and STIR sequences resolved in parallel with improvement of laboratory studies and clinical course.

  5. Magnetic resonance angiography in the management of recurrent hemarthrosis after total knee arthroplasty.

    Science.gov (United States)

    Hash, Thomas W; Maderazo, Alex B; Haas, Steven B; Saboeiro, Gregory R; Trost, David W; Potter, Hollis G

    2011-12-01

    Spontaneous hemarthrosis is an infrequent but disabling complication after total knee arthroplasty. The purpose of this case series is to demonstrate the utility of magnetic resonance angiography (MRA) in the evaluation of hemarthrosis after total knee arthroplasty. Patients presenting with hemarthrosis unexplained by trauma, anticoagulation, or a bleeding diathesis were retrospectively identified. Eighteen patients were referred for MRA to evaluate recurrent hemarthrosis after failing conservative therapy (n = 16) or synovectomy (n = 2). Despite artifact caused by the metallic components, diagnostic evaluation of regional vessels was made. In 12 of 13 cases that underwent embolization or synovectomy, a hypertrophic feeding artery (or arteries) was visualized on MRA. One case of negative MRA did not have subsequent surgery, and we are unable to comment on the rate of false-positives because all patients in this case series had evidence of bleeding. By characterizing the vascular anatomy and identifying a dominant artery (or arteries) supplying the hypervascular synovium, MRA can serve as a guide for subsequent embolization or synovectomy, as indicated.

  6. Magnetic resonance angiography with blood-pool contrast agents: future applications

    Energy Technology Data Exchange (ETDEWEB)

    Fink, C. [Univ. Hospitals, Grosshadern, Munich (Germany); Goyen, M. [Univ. Medical Center, Hamburg-Eppendorf, Hamburg (Germany); Lotz, J. [Hannover Medical School, Hannover (Germany)

    2007-03-15

    Blood pool agents remain in the intravascular space for a longer time period. Therefore the optimal imaging window for vascular structures is widened to about 30 minutes. Gadofosveset trisodium (Vasovist, Bayer Schering Pharma AG, Berlin, Germany) is the first blood-pool contrast agent approved in Europe for contrast-enhanced magnetic resonance angiography (MRA) of vessels in the abdomen, pelvis and lower extremity in adults. Other possible applications of blood-pool agents are now being considered, such as assessment of venous thromboembolism, coronary artery disease or sinus venous thrombosis. Perfusion MR imaging holds promise for detecting lung perfusion defects with higher spatial resolution and reduced scan time compared with radionuclide scintigraphy. In coronary artery disease, blood-pool agents enable a substantial increase in the quality of coronary artery imaging. Quantitative myocardial perfusion and myocardial viability seem to be possible, although modifications in protocols and sequence design are necessary for optimal results. Other novel applications of blood-pool agents include monitoring of inflammatory changes in systemic lupus erythematosus and evaluation of tumour invasion into lymph nodes and more reliable assessment of cerebral venous and sinus thrombosis. (orig.)

  7. Autologous breast reconstruction: preoperative magnetic resonance angiography for perforator flap vessel mapping.

    Science.gov (United States)

    Agrawal, Mukta D; Thimmappa, Nanda Deepa; Vasile, Julie V; Levine, Joshua L; Allen, Robert J; Greenspun, David T; Ahn, Christina Y; Chen, Constance M; Hedgire, Sandeep S; Prince, Martin R

    2015-01-01

    Selection of a vascular pedicle for autologous breast reconstruction is time consuming and depends on visual evaluation during the surgery. Preoperative imaging of donor site for mapping the perforator artery anatomy greatly improves the efficiency of perforator selection and significantly reduces the operative time. In this article, we present our experience with magnetic resonance angiography (MRA) for perforator vessel mapping including MRA technique and interpretation. We have performed over 400 MRA examinations from August 2008 to August 2013 at our institution for preoperative imaging of donor site for mapping the perforator vessel anatomy. Using our optimized imaging protocol with blood pool magnetic resonance imaging contrast agents, multiple donor sites can be imaged in a single MRA examination. Following imaging using the postprocessing and reporting tool, we estimated incidence of commonly used perforators for autologous breast reconstruction. In our practice, anterior abdominal wall tissue is the most commonly used donor site for perforator flap breast reconstruction and deep inferior epigastric artery perforators are the most commonly used vascular pedicle. A thigh flap, based on the profunda femoral artery perforator has become the second most used flap at our institution. In addition, MRA imaging also showed evidence of metastatic disease in 4% of our patient subset. Our MRA technique allows the surgeons to confidently assess multiple donor sites for the best perforator and flap design. In conclusion, a well-performed MRA with specific postprocessing provides an accurate method for mapping perforator vessel, at the same time avoiding ionizing radiation. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  8. Whole-heart magnetic resonance coronary angiography with multiple breath-holds and automatic breathing-level tracking

    Science.gov (United States)

    Kuhara, Shigehide; Ninomiya, Ayako; Okada, Tomohisa; Kanao, Shotaro; Kamae, Toshikazu; Togashi, Kaori

    2010-05-01

    Whole-heart (WH) magnetic resonance coronary angiography (MRCA) studies are usually performed during free breathing while monitoring the position of the diaphragm with real-time motion correction. However, this results in a long scan time and the patient's breathing pattern may change, causing the study to be aborted. Alternatively, WH MRCA can be performed with multiple breath-holds (mBH). However, one problem in the mBH method is that patients cannot hold their breath at the same position every time, leading to image degradation. We have developed a new WH MRCA imaging method that employs both the mBH method and automatic breathing-level tracking to permit automatic tracking of the changes in breathing or breath-hold levels. Evaluation of its effects on WH MRCA image quality showed that this method can provide high-quality images within a shorter scan time. This proposed method is expected to be very useful in clinical WH MRCA studies.

  9. The value of magnetic resonance imaging for the detection of the bleeding source in non-traumatic intracerebral haemorrhages: a comparison with conventional digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Lummel, Nina; Lutz, Juergen; Brueckmann, Hartmut; Linn, Jennifer [University of Munich, Department of Neuroradiology, Munich (Germany)

    2012-07-15

    Conventional digital subtraction angiography (DSA) is currently regarded as the gold standard in detecting underlying vascular pathologies in patients with intracerebral haemorrhages (ICH). However, the use of magnetic resonance imaging (MRI) in the diagnostic workup of ICHs has considerably increased in recent years. Our aim was to evaluate the diagnostic accuracy and yield of MRI for the detection of the underlying aetiology in ICH patients. Sixty-seven consecutive patients with an acute ICH who underwent MRI (including magnetic resonance angiography (MRA) and DSA during their diagnostic workup) were included in the study. Magnetic resonance images were retrospectively analysed by two independent neuroradiologists to determine the localisation and cause of the ICH. DSA was used as a reference standard. In seven patients (10.4%), a DSA-positive vascular aetiology was present (one aneurysm, four arteriovenous malformations, one dural arteriovenous fistula and one vasculitis). All of these cases were correctly diagnosed by both readers on MRI. In addition, MRI revealed the following probable bleeding causes in 39 of the 60 DSA-negative patients: cerebral amyloid angiopathy (17), cavernoma (9), arterial hypertension (8), haemorrhagic transformation of an ischaemic infarction (3) and malignant brain tumour with secondary ICH (2). Performing MRI with MRA proved to be an accurate diagnostic tool in detecting vascular malformations in patients with ICH. In addition, MRI provided valuable information regarding DSA-negative ICH causes, and thus had a high diagnostic yield in ICH patients. (orig.)

  10. Accelerated free breathing ECG triggered contrast enhanced pulmonary vein magnetic resonance angiography using compressed sensing.

    Science.gov (United States)

    Roujol, Sébastien; Foppa, Murilo; Basha, Tamer A; Akçakaya, Mehmet; Kissinger, Kraig V; Goddu, Beth; Berg, Sophie; Nezafat, Reza

    2014-11-22

    To investigate the feasibility of accelerated electrocardiogram (ECG)-triggered contrast enhanced pulmonary vein magnetic resonance angiography (CE-PV MRA) with isotropic spatial resolution using compressed sensing (CS). Nineteen patients (59±13 y, 11 M) referred for MR were scanned using the proposed accelerated free breathing ECG-triggered 3D CE-PV MRA sequence (FOV=340×340×110 mm3, spatial resolution=1.5×1.5×1.5 mm3, acquisition window=140 ms at mid diastole and CS acceleration factor=5) and a conventional first-pass breath-hold non ECG-triggered 3D CE-PV MRA sequence. CS data were reconstructed offline using low-dimensional-structure self-learning and thresholding reconstruction (LOST) CS reconstruction. Quantitative analysis of PV sharpness and subjective qualitative analysis of overall image quality were performed using a 4-point scale (1: poor; 4: excellent). Quantitative PV sharpness was increased using the proposed approach (0.73±0.09 vs. 0.51±0.07 for the conventional CE-PV MRA protocol, p<0.001). There were no significant differences in the subjective image quality scores between the techniques (3.32±0.94 vs. 3.53±0.77 using the proposed technique). CS-accelerated free-breathing ECG-triggered CE-PV MRA allows evaluation of PV anatomy with improved sharpness compared to conventional non-ECG gated first-pass CE-PV MRA. This technique may be a valuable alternative for patients in which the first pass CE-PV MRA fails due to inaccurate first pass timing or inability of the patient to perform a 20-25 seconds breath-hold.

  11. New methods for computational fluid dynamics modeling of carotid artery from magnetic resonance angiography

    Science.gov (United States)

    Cebral, Juan R.; Yim, Peter J.; Loehner, Rainald; Soto, Orlando; Marcos, Hani; Choyke, Peter L.

    2001-05-01

    Computational fluid dynamics (CFD) models of the carotid artery are constructed from contrast-enhanced magnetic resonance angiography (MRA) using a deformable model and a surface-merging algorithm. Physiologic flow conditions are obtained from cine phase-contrast MRA at two slice locations below and above the carotid bifurcation. The methodology was tested on image data from a rigid flow-through phantom of a carotid artery with 65% degree stenosis. Predicted flow patterns are in good agreement with MR flow measurements at intermediate slice locations. Our results show that flow in a rigid flow-through phantom of the carotid bifurcation with stenosis can be simulated accurately with CFD. The methodology was then tested on flow and anatomical data from a normal human subject. The sum of the instantaneous flows measured at the internal and external carotids differs from that at the common carotid, indicating that wall compliance must be modeled. Coupled fluid-structure calculations were able to reproduce the significant dampening of the velocity waveform observed between different slices along the common carotid artery. Visualizations of the blood flow in a compliant model of the carotid bifurcation were produced. A comparison between compliant and rigid models shows significant differences in the time-dependent wall shear stress at selected locations. Our results confirm that image-based CFD techniques can be applied to the modeling of hemodynamics in compliant carotid arteries. These capabilities may eventually allow physicians to enhance current image-based diagnosis, and to predict and evaluate the outcome of interventional procedures non- invasively.

  12. The effectiveness of 3T time-of-flight magnetic resonance angiography for follow-up evaluations after the stent-assisted coil embolization of cerebral aneurysms.

    Science.gov (United States)

    Cho, Won-Sang; Kim, Sam Soo; Lee, Seung Jin; Kim, Sung Hun

    2014-06-01

    Artifacts introduced by stents limit the value of magnetic resonance (MR) imaging as a follow-up modality after the stent-assisted coil embolization of cerebral aneurysms. To investigate the usefulness of 3 Tesla (3T) time-of-flight (TOF) MR angiography (MRA) for the follow-up evaluation. Twenty-two aneurysms of 20 patients treated with stent-assisted coil embolization were followed up with 3T TOF MRA and digital subtraction angiography (DSA) with three-dimensional rotational angiography (3DRA). The status of coiled aneurysms was compared with 3T TOF MRA and DSA with 3DRA in terms of complete occlusion, residual neck, and residual aneurysm. TOF MRA at 3T was performed 1 day before DSA with 3DRA, with a mean follow-up period of 20.1 ± 10.8 months. Twenty (90.9%) of 22 cases were concordant between the two modalities. The degree of agreement and correlation between them were high (κ=0.771, Pcoil embolization of cerebral aneurysms. Further study with a larger patient sample is needed to confirm the effectiveness of 3T TOF MRA. © The Foundation Acta Radiologica 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  13. Magnetic resonance angiography virtual endoscopy in the assessment of pulmonary veins before radiofrequency ablation procedures for atrial fibrillation

    Energy Technology Data Exchange (ETDEWEB)

    Cirillo, S.; Tosetti, Irene; Giuseppe, M.De; Longo, M.; Regge, D. [Institute for Cancer Research and Treatment (IRCC), Unit of Radiology, Candiolo (Torino) (Italy); Bonamini, R. [University of Torino, Department of Cardiology, Torino (Italy); Gaita, F.; Bianchi, F.; Vivalda, L. [Ospedale Mauriziano Umberto I, Department of Cardiology, Torino (Italy)

    2004-11-01

    Magnetic resonance angiography (MRA) is a safe and non-invasive imaging method that can readily depict the pulmonary veins (PV), whose imaging has acquired momentum with the advent of new techniques for radiofrequency ablation of atrial fibrillation (AF). We evaluated whether virtual endoscopy from 3D MRA images (MRA-VE) is feasible in studying the morphology of PV. Fifty patients with AF underwent pre-ablative MRA (1.5 T). Images were acquired with axial T-2 weighted and 3D-SPGR sequences after intravenous administration of Gd-DTPA and automatic triggering. Postprocessing was performed by an experienced radiologist with maximum intensity projection (MIP) and virtual endoscopy software (Navigator, GEMS). The venoatrial junction was visualized with MRA-VE in 49 of 50 patients (98.0%). Twenty-seven patients (55.1%) had two ostia on both sides, 13 patients (26.5%) had two ostia on the right and a single common ostium on the left, 5 patients (10.2%) had accessory PV and 4 patients (8.2%) had both an accessory right PV and a single common ostium on the left. Flythrough navigation showed the number and spatial disposition of second-order PV branches in 48 out of 49 patients (98.0%). MRA-VE is an excellent tool for at-a-glance visualization of ostia morphology, navigation of second-generation PV branches and easy endoluminal assessment of left atrial structures in pre-ablative imaging. (orig.)

  14. Thyroid Incidentaloma Detected by Time-Resolved Magnetic Resonance Angiography at 3T: Prevalence and Clinical Significance

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    Choi, Nami; Moon, Won Jin; Kim, Hahn Young; Roh, Hong Gee; Choi, Jin Woo [Konkuk University Medical Center, Seoul (Korea, Republic of)

    2012-06-15

    To determine the prevalence of thyroid incidentalomas detected by time-resolved magnetic resonance angiography (TRMRA) and to evaluate their clinical significance by using an ultrasonographic (US) and cytologic correlation. We retrospectively reviewed 2010 consecutive TRMRA examinations performed at our institution between August 2006 and April 2010. The TRMRA findings of thyroid incidentalomas were analyzed according to location, size, as well as vascularity, and were correlated with the US findings and cytologic results. Each nodule was classified as suspiciously malignant, indeterminate or probably benign according to the US criteria recommended by the Korean Society of Thyroid Radiology. A total of 102 incidentalomas were detected in 90 of 2010 patients (5%). TRMRA showed homogenous hypervascularity in 48 (47%), inhomogeneous hypervascularity in 46 (45%), and hypovascularity in 8 (8%) thyroid nodules. At follow-up study, out of 26 patients with 30 incidentalomas on TRMRA, 27 nodules were identified on US. Of the 27 nodules, 24 (89%) nodule were classified as indeterminate, two (7%) as probably benign, and one (4%) as suspiciously malignant. Among the 16 nodules with available cytopathologic results, 14 (82%) were benign, one (6%) was indeterminate, and one (6%) was malignant. Thyroid incidentalomas are found in 5% of TRMRA examinations. Although their presence does not necessarily indicate malignancy, nonspecific findings of detected incidentalomas on TRMRA require further evaluation by US.

  15. Factors in the technical quality of gadolinium enhanced magnetic resonance angiography for pulmonary embolism in PIOPED III.

    Science.gov (United States)

    Sostman, H Dirk; Jablonski, Kathleen A; Woodard, Pamela K; Stein, Paul D; Naidich, David P; Chenevert, Thomas L; Weg, John G; Hales, Charles A; Hull, Russell D; Goodman, Lawrence R; Tapson, Victor F

    2012-02-01

    In a multi-center trial, gadolinium enhanced magnetic resonance angiography (MRA) for diagnosis of acute pulmonary embolism (PE) had a high rate of technically inadequate images. Accordingly, we evaluated the reasons for poor quality MRA of the pulmonary arteries in these patients. We performed a retrospective analysis of the data collected in the PIOPED III study. We assessed the relationship to the proportion of examinations deemed "uninterpretable" by central readers to the clinical centers, MR equipment platform and vendors, degree of vascular opacification in different orders of pulmonary arteries; type, frequency and severity of image artifacts; patient co-morbidities, symptoms and signs; and reader characteristics. Centers, MR equipment vendor and platform, degree of vascular opacification, and motion artifacts influenced the likelihood of central reader determinations that images were "uninterpretable". Neither the reader nor patient characteristics (age, body mass index, respiratory rate, heart rate) correlated with the likelihood of determining examinations "uninterpretable". Vascular opacification and motion artifact are the principal factors influencing MRA interpretability. Some centers obtain better images more consistently, but the reasons for differences between centers are unclear.

  16. Dynamic CT head phantom for perfusion and angiography studies

    Science.gov (United States)

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

    2010-03-01

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

  17. Cuff-Compression of the Proximal Calf to Reduce Venous Contamination in Contrast-Enhanced Stepping-Table Magnetic Resonance Angiography

    Energy Technology Data Exchange (ETDEWEB)

    Bilecen, D.; Jaeger, K.A.; Aschwanden, M.; Heidecker, H.G.; Schulte, A.C.; Bongartz, G. [Univ. of Basel (Switzerland). Dept. of Diagnostic Radiology and Dept. of Angiology

    2004-08-01

    Purpose: To minimize venous overlay at the calf station in contrast-enhanced three-dimensional (3D) stepping-table magnetic resonance angiography (MRA) using a continuous cuff-compression technique during MR data acquisition. Material and Methods: Within 14 months, 32 patients suffering from symptomatic peripheral arterial occlusive disease (PAOD) with a bilateral ankle-brachial index (ABI) of 0.8 or below were consecutively enrolled in this study. Unilateral cuff-compression of the proximal calf was applied in the study group (n=14). The control group (n=18) underwent no compression. All patients underwent three-step 3D contrast-enhanced magnetic resonance angiography (3D CE-MRA) according to the institute's protocol. Venous contamination scores (vcs) at the calf station were blindly ranked by a 1 to 3 rating score (3=major venous contamination). The vcs values of the control group were regarded as standard. Statistical significance between both groups was evaluated with a paired t test. Results: Symmetric venous contamination was observed within the control group with a mean vcs of 2.2{+-}0.6 on the left side and 2.2{+-}0.7 on the right side with vcs left-right of 0.1{+-}0.2 (P>0.1). In the study group, asymmetric venous contamination was determined with vcs mean=2.3{+-}0.6 for the uncompressed side and vcs mean=1.4{+-}0.5 for the compressed side and a vcs uncomp-comp of 0.9{+-}0.5 (P<0.00005). The control group and the uncompressed side of the study group showed no significant difference in venous contamination (P>0.1). Conclusion: Subdiastolic cuff-compression of the proximal calf is an easily applicable and inexpensive technique by which to reduce venous contamination of the calf station in stepping-table MR angiography and to improve evaluation of the infrapopliteal arteries.

  18. Dynamic contrast-enhanced magnetic resonance angiography for the localization of spinal dural arteriovenous fistulas at 3T.

    Science.gov (United States)

    Zhou, G; Li, M H; Lu, C; Yin, Y L; Zhu, Y Q; Wei, X E; Lu, H T; Zheng, Q Q; Gao, W W

    2017-02-01

    This study was undertaken to evaluate the accuracy of dynamic contrast-enhanced magnetic resonance angiography (DCE-MRA) in the precise location and demonstration of fistulous points in spinal dural arteriovenous fistulas (SDAVFs). Fifteen patients (14 men, 1 woman; age range: 40-78 years; mean: 55.5 years) harboring SDAVF who underwent preoperative DCE-MRA and spinal digital subtraction angiography (DSA) between January 2012 and January 2015 were evaluated retrospectively. Two reviewers independently evaluated the level and side of the arteriovenous fistula and feeding artery on 3T DCE-MRA and DSA images. The accuracy of DCE-MRA was assessed by comparing its findings with those from DSA and surgery in each case. All 15 patients underwent DCE-MRA and DSA. DSA was unsuccessful in two patients due to technical difficulties. All cases were explored surgically, guided by the DCE-MRA. Surgery confirmed that 14 AVF sites were located in the thoracic spine, 5 in the lumbar spine, and 1 in the cervical spine. The origin of the fistulas and feeding arteries was accurately shown by DCE-MRA in 11 of the 15 patients. DCE-MRA also detected dilated perimedullary veins in all 15 patients. Overall, DCE-MRA facilitated DSA catheterization in 10 cases. In six patients, the artery of Adamkiewicz could be observed. In 15 out of 20 fistulas (75%), both readers agreed on the location on DCE-MRA images, and the κ coefficient of the interobserver agreement was 0.67 (95% confidence interval [CI], 0.16-0.87). In 13 of 16 shunts (75%), the DCE-MRA consensus findings and DSA findings coincided. The intermodality agreement was 0.77 (95% CI: 0.35-0.92). Our DCE-MRA studies benefited from the use of a high-field 3T MR imaging unit and reliably detected and localized the SDAVF and feeding arteries. As experience with this technique grows, it may be possible to replace DSA with DCE-MRA if surgery is the planned treatment. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  19. Parenchymal abnormalities in cerebral venous thrombosis: findings of magnetic resonance imaging and magnetic resonance angiography; Alteracoes parenquimatosas na trombose venosa cerebral: aspectos da ressonancia magnetica e da angiorressonancia

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    Ferreira, Clecia Santos; Pellini, Marcos [Universidade Federal, Rio de Janeiro, RJ (Brazil). Faculdade de Medicina. Dept. de Radiologia]. E-mail: csferreira@superig.com.br; Boasquevisque, Edson [Universidade do Estado do Rio de Janeiro, (UERJ), RJ (Brazil). Faculdade de Medicina. Dept. de Patologia; Souza, Luis Alberto M. de [Hospital da Beneficencia Portuguesa do Rio de Janeiro, RJ (Brazil). Servico de Imagem. Setor de Ressonancia Magnetica

    2006-09-15

    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)

  20. Visualization of periventricular collaterals in moyamoya disease with flow-sensitive black-blood magnetic resonance angiography: preliminary experience.

    Science.gov (United States)

    Funaki, Takeshi; Fushimi, Yasutaka; Takahashi, Jun C; Takagi, Yasushi; Araki, Yoshio; Yoshida, Kazumichi; Kikuchi, Takayuki; Miyamoto, Susumu

    2015-01-01

    Fragile abnormal collaterals in moyamoya disease, known as "moyamoya vessels," have rarely been defined. While flow-sensitive black-blood magnetic resonance angiography (FSBB-MRA) is a promising technique for visualizing perforating arteries, as of this writing no other reports exist regarding its application to moyamoya disease. Six adults with moyamoya disease underwent FSBB-MRA. It depicted abnormal collaterals as extended lenticulostriate, thalamic perforating, or choroidal arteries, which were all connected to the medullary or insular artery in the periventricular area and supplied the cortex. This preliminary case series illustrates the potential for FSBB-MRA to reveal abnormal moyamoya vessels, which could be reasonably defined as periventricular collaterals.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Supra-aortic low-dose contrast-enhanced time-resolved magnetic resonance (MR) angiography at 3 T: comparison with time-of-flight MR angiography and high-resolution contrast-enhanced MR angiography.

    Science.gov (United States)

    Lee, Youn-Joo; Kim, Bum-soo; Koo, Ja-Sung; Kim, Bom-Yi; Jang, Jinhee; Choi, Hyun Seok; Jung, So-Lyung; Ahn, Kook-Jin

    2015-06-01

    Low-dose, time-resolved, contrast-enhanced, magnetic resonance angiography (TR-CEMRA) has been described previously; however, a comparative study between low dose TR-CEMRA and time-of-flight MRA (TOF-MRA) in the diagnosis of supra-aortic arterial stenosis has not yet been published. To demonstrate the feasibility and effectiveness of low-dose TR-CEMRA compared with TOF-MRA, using high-resolution contrast-enhanced MRA (HR-CEMRA) as the reference standard. This prospective study consisted of 30 consecutive patients. All patients underwent TOF-MRA of the neck and circle of Willis and supra-aortic HR-CEMRA, followed by supra-aortic low-dose TR-CEMRA. Gadoterate meglumine (Gd-DOTA, Dotarem(®), Guerbet, Roissy CdG Cedex, France) was injected at a dose of 0.1 mmol/kg for HR-CEMRA, followed by a 0.03 mmol/kg bolus for low-dose TR-CEMRA. Three readers evaluated the assessibility and image quality, and then two readers classified each stenosis into the following categories: normal (0-30%), mild stenosis (31-50%), moderate (51-70%), severe (71-99%), and occlusion. TR-CEMRA and HR-CEMRA showed a greater number of assessable arterial segments than TOF-MRA (P < 0.01). For TR-CEMRA, 29 cases showed within or better than the diagnostic range, whereas all 30 cases were in the diagnostic range for TOF-MRA and HR-CEMRA. For evaluation of stenosis in a total of 743 arterial segments, both TR-CEMRA and TOF-MRA results agreed with those of HR-CEMRA in 729 segments (98.1%), with excellent inter-observer agreement of TR-CEMRA; stenosis was overestimated in nine segments (1.2%) and underestimated in five segments (0.7%). For diagnosis of stenosis using 30% as the cut-off value on HR-CEMRA, the sensitivity and specificity were 88.2% and 99.3%, respectively, for the TR-CEMRA procedure, versus 94.1% and 99.6%, respectively, for TOF-MRA. Low-dose TR-CEMRA is feasible and effective in the diagnosis of supra-aortic arterial stenosis, and could be more useful option than TOF-MRA. © The

  3. The benefit of non contrast-enhanced magnetic resonance angiography for predicting vascular access surgery outcome: a computer model perspective.

    Directory of Open Access Journals (Sweden)

    Maarten A G Merkx

    Full Text Available INTRODUCTION: Vascular access (VA surgery, a prerequisite for hemodialysis treatment of end-stage renal-disease (ESRD patients, is hampered by complication rates, which are frequently related to flow enhancement. To assist in VA surgery planning, a patient-specific computer model for postoperative flow enhancement was developed. The purpose of this study is to assess the benefit of non contrast-enhanced magnetic resonance angiography (NCE-MRA data as patient-specific geometrical input for the model-based prediction of surgery outcome. METHODS: 25 ESRD patients were included in this study. All patients received a NCE-MRA examination of the upper extremity blood vessels in addition to routine ultrasound (US. Local arterial radii were assessed from NCE-MRA and converted to model input using a linear fit per artery. Venous radii were determined with US. The effect of radius measurement uncertainty on model predictions was accounted for by performing Monte-Carlo simulations. The resulting flow prediction interval of the computer model was compared with the postoperative flow obtained from US. Patients with no overlap between model-based prediction and postoperative measurement were further analyzed to determine whether an increase in geometrical detail improved computer model prediction. RESULTS: Overlap between postoperative flows and model-based predictions was obtained for 71% of patients. Detailed inspection of non-overlapping cases revealed that the geometrical details that could be assessed from NCE-MRA explained most of the differences, and moreover, upon addition of these details in the computer model the flow predictions improved. CONCLUSIONS: The results demonstrate clearly that NCE-MRA does provide valuable geometrical information for VA surgery planning. Therefore, it is recommended to use this modality, at least for patients at risk for local or global narrowing of the blood vessels as well as for patients for whom an US-based model

  4. Cerebrovascular reactivity by quantitative magnetic resonance angiography with a co{sub 2} challenge. Validation as a new imaging biomarker

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    Caputi, Luigi, E-mail: lcaputi@istituto-besta.it [Department of Cerebrovascular Diseases, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Ghielmetti, Francesco, E-mail: Francesco.Ghielmetti@istituto-besta.it [Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Faragò, Giuseppe, E-mail: Giuseppe.Farago@istituto-besta.it [Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Longaretti, Fabio, E-mail: fabio.longaretti@libero.it [Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Lamperti, Massimo, E-mail: docmassimomd@gmail.com [Department of Neuroanesthesia and Intensive Care, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Anzola, Gian Paolo, E-mail: gpanzola@speedyposta.it [Service of Neurology, S. Orsola Hospital, Fondazione Poliambulanza, Via Vittorio Emanuele II 27, 25122 Brescia (Italy); Carriero, Maria Rita, E-mail: MariaRita.Carriero@istituto-besta.it [Department of Cerebrovascular Diseases, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Charbel, Fady T., E-mail: fcharbel@uic.edu [Department of Neurosurgery, University of Illinois at Chicago College of Medicine, Chicago, IL 60612 (United States); Bruzzone, Maria Grazia, E-mail: Maria.Bruzzone@istituto-besta.it [Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Parati, Eugenio, E-mail: Eugenio.Parati@istituto-besta.it [Department of Cerebrovascular Diseases, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Ciceri, Elisa, E-mail: Elisa.Ciceri@istituto-besta.it [Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy)

    2014-06-15

    Assessment of cerebrovascular reactivity (CVR) is essential in cerebrovascular diseases, as exhausted CVR may enhance the risk of cerebral ischemic events. Transcranial Doppler (TCD) with a vasodilatory stimulus is currently used for CVR evaluation. Scanty data are available for Quantitative Magnetic Resonance Angiography (QMRA), which supplies higher spatial resolution and quantitative cerebral blood flow values. Aims of our pilot study were: (a) to assess safety and feasibility of CO{sub 2} administration during QMRA, (b) evaluation of CVR under QMRA compared to TCD, and (c) quantitative evaluation of blood flow from the major intracranial arterial vessels both at rest and after CO{sub 2}. CVR during 5% CO{sub 2} air breathing was measured with TCD as a reference method and compared with QMRA. Fifteen healthy subjects (age 60.47 ± 2.24; male 11/15) were evaluated at rest and during CO{sub 2} challenge. Feasibility and safety of QMRA under CO{sub 2} were ensured in all subjects. CVR from middle cerebral artery territory was not statistically different between TCD and MRI (p > 0.05). Mean arterial pressure (MAP) and heart rate (HR) increased during QMRA and TCD (MAP p = 0.007 and p = 0.001; HR p = 0.043 and p = 0.068, respectively). Blood flow values from all intracranial vessels increased after CO{sub 2} inhalation (p < 0.001). CO{sub 2} administration during QMRA sessions is safe and feasible. Good correlation in terms of CVR was obtained comparing TCD and QMRA. Blood flow values significantly increased from all intracranial arterial vessels after CO{sub 2}. Studies regarding CVR in physiopathological conditions might consider the utilization of QMRA both in routine clinical settings and in research projects.

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

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

    2002-08-01

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

  6. Follow-up after embolization of ruptured intracranial aneurysms: A prospective comparison of two-dimensional digital subtraction angiography, three-dimensional digital subtraction angiography, and time-of-flight magnetic resonance angiography

    Energy Technology Data Exchange (ETDEWEB)

    Serafin, Zbigniew; Strzesniewski, Piotr; Lasek, Wladyslaw [Nicolaus Copernicus University, Collegium Medicum, Department of Radiology and Diagnostic Imaging, Bydgoszcz (Poland); Beuth, Wojciech [Nicolaus Copernicus University, Collegium Medicum, Department of Neurosurgery and Neurotraumatology, Bydgoszcz (Poland)

    2012-11-15

    To prospectively compare of the diagnostic value of digital subtraction angiography (DSA) and time-of-flight magnetic resonance angiography (TOF-MRA) in the follow-up of intracranial aneurysms after endovascular treatment. Seventy-two consecutive patients were examined 3 months after the embolization. The index tests included: two-dimensional DSA (2D-DSA), three-dimensional DSA (3D-DSA), and TOF-MRA. The reference test was a retrospective consensus between 2D-DSA images, 3D-DSA images, and source rotational DSA images. The evaluation included: detection of the residual flow, quantification of the flow, and validity of the decision regarding retreatment. Intraobserver agreement and interobserver agreement were determined. The sensitivity and specificity of residual flow detection ranged from 84.6 % (2D-DSA and TOF-MRA) to 92.3 % (3D-DSA) and from 91.3 % (TOF-MRA) to 97.8 % (3D-DSA), respectively. The accuracy of occlusion degree evaluation ranged from 0.78 (2D-DSA) to 0.92 (3D-DSA, Cohen's kappa). The 2D-DSA method presented lower performance in the decision on retreatment than 3D-DSA (P < 0.05, ROC analysis). The intraobserver agreement was very good for all techniques ({kappa} = 0.80-0.97). The interobserver agreement was moderate for TOF-MRA and very good for 2D-DSA and 3D-DSA ({kappa} = 0.72-0.94). Considering the invasiveness of DSA and the minor difference in the diagnostic performance between 3D-DSA and TOF-MRA, the latter method should be the first-line modality for follow-up after aneurysm embolization. (orig.)

  7. 3D-FIESTA Magnetic Resonance Angiography Fusion Imaging of Distal Segment of Occluded Middle Cerebral Artery.

    Science.gov (United States)

    Kuribara, Tomoyoshi; Haraguchi, Koichi; Ogane, Kazumi; Matsuura, Nobuki; Ito, Takeo

    2015-01-01

    Middle cerebral artery (MCA) occlusion was examined with basi-parallel anatomical scanning (BPAS) using three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA), and 3D-FIESTA and magnetic resonance angiography (MRA) fusion images were created. We expected that an incidence of hemorrhagic complications due to vessel perforations would be decreased by obtaining vascular information beyond the occlusion and thus acute endovascular revascularization could be performed using such techniques. We performed revascularization for acute MCA occlusion for five patients who were admitted in our hospital from October 2012 to October 2014. Patients consisted of 1 man and 4 women with a mean age of 76.2 years (range: 59-86 years). Fusion images were created from three-dimensional time of flight (3D-TOF) MRA and 3D-FIESTA with phase cycling (3D-FIESTA-C). Then thrombectomy was performed in all the 5 patients. Merci retriever to 1 patient, Penumbra system to 1, urokinase infusion to 2, and Solitaire to 1 using such techniques. In all cases, a 3D-FIESTA-MRA fusion imaging could depict approximately clear vascular information to at least the M3 segment beyond the occlusion. And each acute revascularization was able to perform smoothly using these imaging techniques. In all cases, there was no symptomatic hemorrhagic complication. It showed that 3D-FIESTA MRA fusion imaging technique could obtain vascular information beyond the MCA occlusion. In this study, no symptomatic hemorrhagic complications were detected. It could imply that such techniques were useful not only to improve treatment efficiency but also to reduce the risk of development of hemorrhagic complications caused by vessel perforations in acute revascularization.

  8. Antibodies to the α1-adrenergic receptor cause vascular impairments in rat brain as demonstrated by magnetic resonance angiography.

    Directory of Open Access Journals (Sweden)

    Peter Karczewski

    Full Text Available BACKGROUND: Circulating agonistic autoantibodies acting at G protein-coupled receptors have been associated with numerous sever pathologies in humans. Antibodies directed predominantly against the α(1-adrenergig receptor were detected in patients suffering from widespread diseases such as hypertension and type 2 diabetes. Their deleterious action has been demonstrated for peripheral organs. We postulate that antibodies to the α(1-adrenergig receptor are relevant pathomolecules in diseases of the central nervous system associated with vascular impairments. METHODOLOGY/PRINCIPAL FINDINGS: Using a rat model we studied the long-term action of antibodies against the α(1-adrenergig receptor either induced by immunization with a receptor peptide or applied by intravenous injection. The vasculature in the rat brains was investigated by time-of-flight magnetic resonance angiography using a 9.4 Tesla small animal MR imaging system. Visual examination of maximum-intensity-projections (MIPs of brain angiographs revealed the development of vascular defects in antibody- exposed animals between three and eight months of treatment. Relative vascular areas were derived from representative MIP image sections by grayscale analysis and used to form an index of vascular circulation. Animals exposed to the action of α(1-adrenergig receptor antibodies showed significantly reduced vascular areas (p<0.05. Calculated index values indicated attenuated blood flow in both antibody-treated cohorts compared to their respective controls reaching with (relative units ± standard error, n = 10 0.839 ± 0.026 versus 0.919 ± 0.026 statistical significance (p<0.05 for peptide-immunized rats. CONCLUSION/SIGNIFICANCE: We present evidence that antibodies to the α(1-adrenergig receptor cause cerebrovascular impairments in the rat. Our findings suggest the pathological significance of these antibodies in pathologies of the human central nervous system linked to impairments of

  9. Vulnerable atherosclerotic carotid plaque evaluation by ultrasound, computed tomography angiography, and magnetic resonance imaging: an overview.

    Science.gov (United States)

    Naim, Cyrille; Douziech, Maxime; Therasse, Eric; Robillard, Pierre; Giroux, Marie-France; Arsenault, Frederic; Cloutier, Guy; Soulez, Gilles

    2014-08-01

    Ischemic syndromes associated with carotid atherosclerotic disease are often related to plaque rupture. The benefit of endarterectomy for high-grade carotid stenosis in symptomatic patients has been established. However, in asymptomatic patients, the benefit of endarterectomy remains equivocal. Current research seeks to risk stratify asymptomatic patients by characterizing vulnerable, rupture-prone atherosclerotic plaques. Plaque composition, biology, and biomechanics are studied by noninvasive imaging techniques such as magnetic resonance imaging, computed tomography, ultrasound, and ultrasound elastography. These techniques are at a developmental stage and have yet to be used in clinical practice. This review will describe noninvasive techniques in ultrasound, magnetic resonance imaging, and computed tomography imaging modalities used to characterize atherosclerotic plaque, and will discuss their potential clinical applications, benefits, and drawbacks. Copyright © 2014 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

  10. Contrast enhanced magnetic resonance angiography for determining patency of coronary bypass grafts. A comparison with coronary angiography; Kontrastmittelverstaerkte Magnetresonanzangiographie zur Ueberpruefung der Durchgaengigkeit koronarer Bypasses. Vergleich zur Koronarangiographie

    Energy Technology Data Exchange (ETDEWEB)

    Wintersperger, B.J.; Smekal, A. von; Penzkofer, H.V.; Reiser, M. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern der Ludwig-Maximilians-Universitaet Muenchen (Germany); Engelmann, M.G.; Knez, A. [1. Medizinische Klinik und Poliklinik, Klinikum Grosshadern der Ludwig-Maximilians-Universitaet Muenchen (Germany); Laub, G. [Siemens AG, Erlangen (Germany). Bereich Medizintechnik

    1997-12-01

    Aim: Assessment of graft patency with current non-invasive MRA techniques is particularly difficult for evaluating internal mammary artery grafts. Our aim is to determine the accuracy of a contrast enhanced MRA technique in assessing graft patency. Methods: We examined 19 patients with a total of 53 grafts (32 venous/21 arterial), using an ultrafast contrast enhanced 3D gradient-echo technique and compared this with the results of selective angiography. Results: Sensitivity of the contrast enhanced method was 95.2% for venous grafts, 94.4% for IMA grafts and 94.8% overall. Specificity was 85.7% overall, 90.9% for venous and 66.7% for IMA grafts. Positive predictive value was 94.4%. Conclusion: Compared with previous studies, visualisation of IMA grafts was improved by using contrast enhanced MRA. In this preliminary study, contrast enhanced MRA proved promising for the assessment of graft patency. (orig.) [Deutsch] Ziel: Die Bestimmung der Durchgaengigkeit koronarer Bypasses mit bisherigen, nichtinvasiven Methoden der Magnetresonanzangiographie (MRA) erwies sich insbesondere beim A.-mammaria-interna-Bypass (IMA) als schwierig. In unseren Untersuchungen soll die Wertigkeit einer kontrastverstaerkten MRA-Technik zur Ueberpruefung der Bypassdurchgaengigkeit bestimmt werden. Methoden: Wir untersuchten 19 Patienten mit insgesamt 53 Bypasses (32 ACVB/21 IMA) mit einer ultraschnellen, kontrastverstaerkten 3D-Gradienten-Echo-Technik im Vergleich zur selektiven Angiographie. Ergebnisse: Die Sensitivitaet der kontrastverstaerkten Methode betrug 95,2% fuer ACVBs, 94,4% fuer IMA-Bypasses und insgesamt 94,8%. Die Spezifitaet lag insgesamt bei 85,7%, fuer ACVB`s 90,9% und fuer IMA-Bypasses 66,7%. Der positive Vorhersagewert betrug 94,9%. Schlussfolgerung: Im Vergleich zu bisherigen Studien ist die Darstellung von IMA-Bypasses deutlich verbessert und zuverlaessiger. In ersten Ergebnissen stellt die kontrastverstaerkte MRA eine relativ einfache und schnelle Methode zur Bestimmung

  11. Accuracy of Noncontrast Quiescent-Interval Single-Shot Lower Extremity MR Angiography Versus CT Angiography for Diagnosis of Peripheral Artery Disease : Comparison With Digital Subtraction Angiography

    NARCIS (Netherlands)

    Varga-Szemes, Akos; Wichmann, Julian L; Schoepf, U Joseph; Suranyi, Pal; De Cecco, Carlo N; Muscogiuri, Giuseppe; Caruso, Damiano; Yamada, Ricardo T; Litwin, Sheldon E; Tesche, Christian; Duguay, Taylor M; Giri, Shivraman; Vliegenthart, Rozemarijn; Todoran, Thomas M

    2017-01-01

    OBJECTIVES: This study sought to evaluate the image quality and diagnostic accuracy of noncontrast quiescent-interval single-shot (QISS) magnetic resonance angiography (MRA) versus iodine-contrast computed tomography angiography (CTA) in patients with peripheral artery disease (PAD), with invasive d

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-15

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

  13. Cardiac magnetic resonance and computed tomography angiography for clinical imaging of stable coronary artery disease. Diagnostic classification and risk stratification

    Science.gov (United States)

    Korosoglou, Grigorios; Giusca, Sorin; Gitsioudis, Gitsios; Erbel, Christian; Katus, Hugo A.

    2014-01-01

    Despite advances in the pharmacologic and interventional treatment of coronary artery disease (CAD), atherosclerosis remains the leading cause of death in Western societies. X-ray coronary angiography has been the modality of choice for diagnosing the presence and extent of CAD. However, this technique is invasive and provides limited information on the composition of atherosclerotic plaque. Coronary computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR) have emerged as promising non-invasive techniques for the clinical imaging of CAD. Hereby, CCTA allows for visualization of coronary calcification, lumen narrowing and atherosclerotic plaque composition. In this regard, data from the CONFIRM Registry recently demonstrated that both atherosclerotic plaque burden and lumen narrowing exhibit incremental value for the prediction of future cardiac events. However, due to technical limitations with CCTA, resulting in false positive or negative results in the presence of severe calcification or motion artifacts, this technique cannot entirely replace invasive angiography at the present time. CMR on the other hand, provides accurate assessment of the myocardial function due to its high spatial and temporal resolution and intrinsic blood-to-tissue contrast. Hereby, regional wall motion and perfusion abnormalities, during dobutamine or vasodilator stress, precede the development of ST-segment depression and anginal symptoms enabling the detection of functionally significant CAD. While CT generally offers better spatial resolution, the versatility of CMR can provide information on myocardial function, perfusion, and viability, all without ionizing radiation for the patients. Technical developments with these 2 non-invasive imaging tools and their current implementation in the clinical imaging of CAD will be presented and discussed herein. PMID:25147526

  14. Multicenter phase-II trial of safety and efficacy of NC100150 for steady-state contrast-enhanced peripheral magnetic resonance angiography

    NARCIS (Netherlands)

    Leiner, T; Ho, KYJAM; Ho, VB; Bongartz, G; Mali, WPTM; Rasch, W; van Engelshoven, JMA

    2003-01-01

    The aim of this study was to test the safety and efficacy of NC100150 injection for steady-state contrast-enhanced peripheral MR angiography in a multicentre phase-II trial. Thirty-three patients underwent steady-state NC100150 enhanced MR angiography (5 mg Fe/kg body weight) of the aortoiliac and f

  15. Role of high resolution contrast-enhanced magnetic resonance angiography (HR CeMRA) in management of arterial complications of the renal transplant

    Energy Technology Data Exchange (ETDEWEB)

    Ismaeel, M. Maged [Suez Canal University (Egypt); Abdel-Hamid, Azza, E-mail: azza4951@hotmail.com [Suez Canal University (Egypt)

    2011-08-15

    Introduction: Transplant renal artery (RA) stenosis (TRAS) is the most frequent posttransplantation vascular complication. Contrast enhanced magnetic resonance (CeMRA) angiography has been established as the preferred imaging technique for the evaluation of TRAS because it does not require the use of iodinated contrast material and does not expose the patient to ionizing radiation. Digital subtraction angiography (DSA) is the gold standard in the evaluation of arterial tree of the renal allograft. Aim of the work: This study was carried out to assess the accuracy of CeMRA in the detection of arterial complications after renal transplantation. Patients and methods: Thirty renal transplant patients with suspected arterial complications in which both CeMRA and DSA were performed were included in the study. The HR CeMRA shows 93.7% sensitivity, 80% specificity, 88.2% positive predictive value, 88.9% negative predictive value and 88.5% accuracy. Conclusion: HR CeMRA is an accurate reliable tool in the assessment of arterial complications after renal transplantation. It may replace DSA as a diagnostic modality with reservation of interventional techniques for endovascular treatment of suitable cases.

  16. Off-resonance-robust velocity-selective magnetization preparation for non-contrast-enhanced peripheral MR angiography.

    Science.gov (United States)

    Shin, Taehoon; Hu, Bob S; Nishimura, Dwight G

    2013-11-01

    To develop a new velocity-selective (VS) excitation pulse sequence which is robust to field inhomogeneity, and demonstrate its application to non-contrast-enhanced peripheral MR angiography (MRA). The off-resonance-robust VS saturation pulse is designed by incorporating 180° refocusing pulses into the k-space-based reference design and tailoring sequence parameters in a velocity region of interest. The VS saturation pulse is used as magnetization preparation for non-contrast-enhanced peripheral MRA to suppress background tissues but not arterial blood based on their velocities. Non-contrast-enhanced peripheral MRA using the proposed VS preparation was tested in healthy volunteers and a patient with arterial stenosis. Calf angiograms obtained using the new VS preparation show more uniform background suppression than the reference VS preparation, as demonstrated by larger mean values and smaller standard deviations of artery-to-vein and artery-to-muscle contrast-to-noise ratios (71.0 ± 11.4 and 75.3 ± 12.1 versus 61.7 ± 22.7 and 58.5 ± 27.8). Two-station peripheral MRA using the new VS preparation identifies stenosis of the femoral and popliteal arteries in the patient, as validated by digital subtraction angiography. Non-contrast-enhanced MRA using the new VS magnetization preparation can reliably provide high angiographic contrast in the lower extremities with significantly improved immunity to field inhomogeneity. Copyright © 2012 Wiley Periodicals, Inc.

  17. Value of Subtraction in Fat-Saturated Three-Dimensional Contrast-Enhanced Magnetic Resonance Angiography of the Hemodialysis Fistula

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, N.; Sato, M.; Niitsu, M.; Saida, Y. [Univ. of Tsukuba Hospital, Ibaraki (Japan). Dept. of Radiology

    2004-10-01

    Purpose: To evaluate image subtraction in a three-dimensional contrast-enhanced magnetic resonance angiography (3D CE-MRA) using fat suppression for the hemodialysis fistula. Material and Methods: Fifteen patients suffering from hemodialysis fistula dysfunction were imaged with 3D CE-MRA using fat suppression and digital subtraction angiography (DSA). Non-subtracted and subtracted MRA images using maximum intensity projection (MIP) were constructed and the validity of the MRA interpretations of the degree of vascular stenoses was evaluated using DSA as the standard of reference. Image quality was assessed using qualitative analysis (vessel contrast) and quantitative analysis (contrast-to-noise ratio (CNR) of the vessel versus the background). Results: In the vessels with stenosis of 50% or greater, the sensitivity and specificity of the non-subtracted MRA were 89.5% and 81.8%, respectively, and of the subtracted MRA 89.5% and 86.4%, respectively. There was no significant difference in the detectability of stenoses between either MRA. The vessel contrast of the anterior interosseous artery and the CNR of the anterior interosseous artery versus the background on the subtracted MRA were significantly superior to those on the non-subtracted MRA. With regard to the radial artery and cephalic vein, there was no significant difference in the vessel contrast and CNR between either MRA. Conclusion: Both subtracted and non-subtracted MRA techniques are useful in detecting hemodialysis fistula dysfunction.

  18. Ultrasound and magnetic resonance angiography features of post-traumatic ulnar artery pseudoaneurysm: a case report and review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Coll Gimenez, David; Valencoso Gilabert, Oscar; Yanguas Muns, Carles [Fundacio Althaia. Xarxa Assistencial de Manresa, Department of Radiology, Barcelona (Spain); Gimenez Ruiz, Joan [Institut Medic per la Imatge, Department of Radiology, Barcelona (Spain); Badal Alter, Josep [Fundacio Althaia, Xarxa Assistencial de Manresa, Department of Pathology, Barcelona (Spain); Rosines Cubells, M.D. [Fundacio Althaia, Xarxa Assistencial de Manresa, Department of Orthopaedic Surgery, Barcelona (Spain)

    2009-09-15

    Ulnar artery pseudoaneurysms are very uncommon. The least common etiological mechanism is a single direct trauma. It is important to identify these lesions, which may have important clinical complications such as distal thrombosis with digital ischemia or gangrene. This report describes the features of sonography and magnetic resonance angiography of a histologically confirmed ulnar artery pseudoaneurysm. (orig.)

  19. Non-invasive diagnostic workup of patients with suspected stable angina by combined computed tomography coronary angiography and magnetic resonance perfusion imaging

    NARCIS (Netherlands)

    S.W.M. Kirschbaum (Sharon); K. Nieman (Koen); T. Springeling (Tirza); A.C. Weustink (Annick); S. Ramcharitar (Steve); C.A.G. van Mieghem (Carlos); A.G. Rossi (Adriano); E. Duckers (Eric); P.W.J.C. Serruys (Patrick); H. Boersma (Eric); P.J. de Feyter (Pim); R.J.M. van Geuns (Robert Jan)

    2011-01-01

    textabstractBackground: To evaluate additional adenosine magnetic resonance perfusion (MRP) imaging in the diagnostic workup of patients with suspected stable angina with computed tomography coronary angiography (CTCA) as first-line diagnostic modality. Methods and Results: Two hundred and thirty sy

  20. Noncontrast-Enhanced Magnetic Resonance Versus Computed Tomography Angiography in Preoperative Evaluation of Potential Living Renal Donors

    DEFF Research Database (Denmark)

    Blankholm, Anne Dorte; Pedersen, Bodil G; Østrat, Ernst Ø

    2015-01-01

    RATIONALE AND OBJECTIVES: Living renal donors undergo an extensive examination program. These examinations should be as safe, gentle, and patient friendly as possible. To compare computed tomography angiography (CTA) and an extensive magnetic resonance imaging (MRI) protocol without contrast agents...... to observations from nephrectomy in living renal donors and to evaluate whether noncontrast-enhanced MRI can replace CTA for vessel assessment in living renal donors. MATERIAL AND METHODS: CTA and MRI results were compared to observations from nephrectomy, which served as the reference standard. Fifty......-one potential kidney donors underwent imaging, and 31 donated a kidney. Comparisons in sensitivity, specificity, and accuracy were made with respect to the number of arteries, early branching, and the number of veins. Agreement was assessed using Cohen's kappa. The exact McNemar's test was used to test...

  1. Preoperative detection of the neurovascular relationship in trigeminal neuralgia using three-dimensional fast imaging employing steady-state acquisition (FIESTA) and magnetic resonance angiography (MRA).

    Science.gov (United States)

    Zeng, QingShi; Zhou, Qin; Liu, ZhiLing; Li, ChuanFu; Ni, ShiLei; Xue, Feng

    2013-01-01

    Microvascular decompression is an accepted treatment for trigeminal neuralgia (TN). Preoperative identification of neurovascular compression, therefore, could aid determination of the appropriate treatment for TN. To preoperatively visualize the neurovascular relationship, three-dimensional fast imaging employing steady-state acquisition (3D FIESTA) and magnetic resonance angiography (MRA) were performed on 37 patients with TN in our study. 3D FIESTA in combination with MRA identified surgically verified neurovascular contact in 35 of 36 symptomatic nerves. The offending vessel (artery or vein) was correctly identified in 94.4% of patients, and agreement between preoperative MRI visualization and surgical findings was excellent (k=0.92; 95% confidence interval, 0.67-1.00). Thus, 3D FIESTA in combination with MRA is useful in the detection of vascular contact with the trigeminal nerve in patients with TN. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Noncontrast-Enhanced Magnetic Resonance Versus Computed Tomography Angiography in Preoperative Evaluation of Potential Living Renal Donors.

    Science.gov (United States)

    Blankholm, Anne Dorte; Pedersen, Bodil G; Østrat, Ernst Ø; Andersen, Gratien; Stausbøl-Grøn, Brian; Laustsen, Susse; Ringgaard, Steffen

    2015-11-01

    Living renal donors undergo an extensive examination program. These examinations should be as safe, gentle, and patient friendly as possible. To compare computed tomography angiography (CTA) and an extensive magnetic resonance imaging (MRI) protocol without contrast agents to observations from nephrectomy in living renal donors and to evaluate whether noncontrast-enhanced MRI can replace CTA for vessel assessment in living renal donors. CTA and MRI results were compared to observations from nephrectomy, which served as the reference standard. Fifty-one potential kidney donors underwent imaging, and 31 donated a kidney. Comparisons in sensitivity, specificity, and accuracy were made with respect to the number of arteries, early branching, and the number of veins. Agreement was assessed using Cohen's kappa. The exact McNemar's test was used to test for statistically significant differences. In the assessment of more than one renal artery, the sensitivity and specificity of MRI and CTA were high and in perfect agreement compared to observations from surgery. The results for both MRI and CTA were as follows: (sensitivity 100%/specificity100%/accuracy 100%/Kappa = 1/P = 1). When comparing the ability to test for early branching we found, MRI: (sensitivity 33%/specificity 100%/accuracy 87%/Kappa = 0.45/P = 1) and CTA: (sensitivity 50%/specificity 100%/accuracy 90%/Kappa = 0.62/P = 1). When used to depict supernumerary veins, we found MRI: (sensitivity60%/specifivity100%/accuracy 93%/Kappa = 0.72/P = 1), whereas CTA showed: (sensitivity 40%/specificity 96%/accuracy 87% Kappa = 0.43/P = 1). In conclusion, an optimized MRI protocol that includes noncontrast-enhanced magnetic resonance angiography can be substituted for CTA for preoperative assessment of the renal vessels before living donor nephrectomy. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  3. Diagnostic accuracy of colour Doppler ultrasonography, CT angiography and blood-pool-enhanced MR angiography in assessing carotid stenosis: a comparative study with DSA in 170 patients.

    Science.gov (United States)

    Anzidei, M; Napoli, A; Zaccagna, F; Di Paolo, P; Saba, L; Cavallo Marincola, B; Zini, C; Cartocci, G; Di Mare, L; Catalano, C; Passariello, R

    2012-02-01

    This study was undertaken to prospectively evaluate the diagnostic performance of colour Doppler ultrasonography (CDUS), first-pass (FP) and steady-state (SS) contrast-enhanced magnetic resonance angiography (MRA) and computed tomography angiography (CTA) of the carotid arteries using digital subtraction angiography (DSA) as the reference standard. A total of 170 patients with previous cerebrovascular events and suspected carotid artery stenoses underwent CDUS, blood-pool MRA, CTA and DSA. Accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for CDUS, FP MRA, SS MRA and CTA. The McNemar and Wilcoxon tests and receiver operating characteristic (ROC) curve analysis were used to determine significant differences (p<0.05) between the diagnostic performances of the four modalities, and the degree of stenosis was compared using linear regression. A total of 336 carotid bifurcations were studied. The area under the curve (AUC) for degree of stenosis was: CDUS 0.85±0.02, FP MRA 0.982±0.005, SS MRA 0.994±0.002 and CTA 0.997±0.001. AUC analysis showed no statistically significant difference between CTA and MRA (p=0.0174) and a statistically significant difference between CDUS and the other techniques (p<0.001). Plaque morphology analysis showed no significant difference between CTA and SS MRA; a significant difference was seen between CTA and SS MRA versus FP MRA (p=0.04) and CDUS (p=0.038). Plaque ulceration analysis showed a statistically significant difference between MRA and CTA (0.04< p<0.046) versus CDUS (p=0.019). CTA is the most accurate technique for evaluating carotid stenoses, with a slightly better performance than MRA (97% vs. 95% for SS MRA and 92% for FP MRA) and a greater accuracy than CDUS (97% vs. 76%). Blood-pool contrast-enhanced SS sequences offer improved evaluation of degree of stenosis and plaque morphology with accuracy substantially identical to CTA.

  4. Time-resolved Magnetic Resonance Angiography for assessment of recanalization after coil embolization of visceral artery aneurysms.

    Science.gov (United States)

    Kurosaka, Kenichiro; Kawai, Tatsuya; Shimohira, Masashi; Hashizume, Takuya; Ohta, Kengo; Suzuki, Yosuke; Shibamoto, Yuta

    2013-01-01

    Follow-up imaging after coil embolization of visceral artery aneurysms is important for detecting recanalization. However, CT examination is susceptible to coil artifacts, which sometimes makes it difficult to assess recanalization. We report 2 cases where recanalization was successfully visualized using time-resolved magnetic resonance angiography after coil embolization of visceral artery aneurysms (one case of right internal iliac artery aneurysm and one case of splenic artery aneurysm). Repeat coil embolization was successfully performed. Case 1. An 80-year-old male patient with right internal iliac artery (IIA) aneurysm underwent coil embolization. Aneurysm was located at the bifurcation of the right IIA and therefore, after making a femorofemoral bypass, the distal part of the right IIA, aneurysm and the common iliac artery were embolized with a coil. One year later, the size of the aneurysm seemed to have increased on CT. However, the details were not determined because of metal artifacts. Thus, time-resolved MRA was performed and showed minute vascular flow inside the aneurysm. Angiography was subsequently performed and blood flow inside the aneurysm was visualized similar to the findings in time-resolved MRA. Coil embolization was performed once more and vascular flow inside the aneurysm disappeared. Case 2. A 36-year-old male patient with a splenic artery aneurysm underwent coil packing with preservation of splenic artery patency. Four years later, coil compaction was suspected in a CT scan, but CT could not evaluate recanalization because of severe metal artifacts. Angiography was subsequently performed, showing recanalization of the aneurysm as did the time-resolved MRA. Therefore, coil embolization of the aneurysm and splenic artery was performed again. Follow-up imaging after coil embolization of visceral artery aneurysms is important for detecting recanalization. However, it is sometimes difficult to assess recanalization with CT because of artifacts

  5. A Comparison of Magnetic Resonance Angiography Techniques for the Evaluation of Intracranial Aneurysms Treated With Stent-assisted Coil Embolization.

    Science.gov (United States)

    Thamburaj, Krishnamoorthy; Cockroft, Kevin; Agarwal, Amit K; Sabat, Shyam; Kalapos, Paul

    2016-12-02

    To identify the effective magnetic resonance angiography (MRA) technique to monitor intracranial aneurysms treated with stent-assisted coiling. Retrospective analysis of various MRA techniques was performed in 42 patients. Three neuroradiologists independently compared non-contrast time of flight (ncTOF) MRA of the head, contrast-enhanced time of flight (cTOF) MRA of the head and dynamic contrast-enhanced MRA (CEMRA) of the head and neck or of the head. Digital subtraction angiography (DSA) was available for comparison in 32 cases. Inter-rater agreement (kappa statistic) was assessed. Artifactual in-stent severe stenosis or flow gap was identified by ncTOF MRA in 23 of 42 cases (55%) and by cTOF MRA in 23 of 38 cases (60%). DSA excluded in-stent stenosis or occlusion in all 32 cases. No difference was noted between ncTOF and cTOF in the demonstration of neck remnants or residual aneurysms in three cases each. CEMRA of the head and neck or of the head was rated superior to ncTOF and cTOF MRA by all three investigators in seven out of eight cases. In one case, all three techniques demonstrated signifcant artifacts due to double stent placement during coiling. The kappa statistic revealed 0.8 agreement between investigators. In the assessment of stent-assisted coiling of intracranial aneurysm, both ncTOF and cTOF MRA show similar results. CEMRA tends to show better flow signals in stent and residual aneurysm.

  6. Safety of cardiac magnetic resonance and contrast angiography for neonates and small infants: a 10-year single-institution experience

    Energy Technology Data Exchange (ETDEWEB)

    Rangamani, Sheela; Li, Ling; Harvey, Lisa; Fletcher, Scott E.; Danford, David A.; Kutty, Shelby [University of Nebraska College of Medicine/Creighton University School of Medicine, Joint Division of Pediatric Cardiology, Omaha, NE (United States); Varghese, Joby [Children' s Hospital and Medical Center, Division of Pediatric Cardiac Anesthesia, Omaha, NE (United States); Hammel, James M.; Duncan, Kim F. [Children' s Hospital and Medical Center, Division of Cardiothoracic Surgery, Omaha, NE (United States)

    2012-11-15

    With increasing applications of cardiac magnetic resonance (CMR) and magnetic resonance angiography (MRA) for evaluation of congenital heart disease (CHD), safety of this technology in the very young is of particular interest. We report our 10-year experience with CMR in neonates and small infants with particular focus on the safety profile and incidence of adverse events (AEs). We reviewed clinical, anesthesia and nursing records of all children {<=}120 days of age who underwent CMR. We recorded variables including cardiac diagnosis, study duration, anesthesia type and agents, prostaglandin E1 (PGE1) dependence and gadolinium (Gd) use. Serially recorded temperature, systemic saturation (SpO{sub 2}) and cardiac rhythm were analyzed. Primary outcome measure was any AE during or <24 h after the procedure, including minor AEs such as hypothermia (axillary temperature {<=}95 F), desaturation (SpO{sub 2} drop {>=}10% below baseline) and bradycardia (heart rate {<=}100 bpm). Secondary outcome measure was unplanned overnight hospitalization of outpatients. Children (n = 143; 74 boys, 69 girls) had a median age of 6 days (1-117), and 98 were {<=}30 days at the time of CMR. The median weight was 3.4 kg (1.4-6 kg) and body surface area 0.22 m{sup 2} (0.13-0.32 m{sup 2}). There were 118 (83%) inpatients (108 receiving intensive care) and 25 (17%) outpatients. Indications for CMR were assessment of aortic arch (n = 57), complex CHD (n = 41), pulmonary veins (n = 15), vascular ring (n = 8), intracardiac mass (n = 8), pulmonary artery (n = 7), ventricular volume (n = 4), and systemic veins (n = 3). CMR was performed using a 1.5-T scanner and a commercially available coil. CMR utilized general anesthesia (GA) in 86 children, deep sedation (DS) in 50 and comforting methods in seven. MRA was performed in 136 children. Fifty-nine children were PGE1-dependent and 39 had single-ventricle circulation. Among children on PGE1, 43 (73%) had GA and 10 (17%) had DS. Twelve children (9%) had

  7. Catheter Angiography

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    Full Text Available ... What are the limitations of Catheter Angiography? What is Catheter Angiography? Angiography is a minimally invasive medical ... them appear bright white. top of page How is the procedure performed? This examination is usually done ...

  8. Catheter Angiography

    Medline Plus

    Full Text Available ... medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ... Angiography (CTA) X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Catheter Angiography Sponsored ...

  9. Phase-Contrast Magnetic Resonance Angiography Measurements of Global Cerebral Blood Flow in the Neonate

    NARCIS (Netherlands)

    Benders, Manon J. N. L.; Hendrikse, Jeroen; de Vries, Linda S.; van Bel, Frank; Groenendaal, Floris

    2011-01-01

    Cerebral blood flow (CBF) alterations are important in pathogenesis of neonatal ischemic/hemorrhagic brain damage. In clinical practice, estimation of neonatal CBF is mostly based on Doppler-measured blood flow velocities in major intracranial arteries. Using phase-contrast magnetic resonance angiog

  10. Radiological findings of dissecting aneurysm -a correlative study of CT with angiography-

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Tae Yeong; Park, Jae Hyung; Kim, Seung Hyup; Han, Man Chung [College of Medicine, Seoul National University, Seoul (Korea, Republic of)

    1987-06-15

    This study comprised 16 patients with aortic dissecting aneurysm who were admitted to Seoul National University Hospital from May 1984 to January 1987. CT findings in 16 cases of aortic dissecting aneurysm were correlated with angiographic findings retrospectively. The results were analysed. 1. Number of male was 11 and that of female was 5. Male patients in fifties were most common and 4 in number. 13 patients had hypertension or history of hypertension among 14 patients. There were one case of Marfan's syndrome, preeclampsia and Takayasu's arteritis respectively. 2. There were 5 cases of DeBakey type I, 1 case of type II and 9 cases of types III dissecting aneurysm. Type III was most common. 3. CT confirmed as superior vena cava which was not identified whether it was superior vena cava or unopacified false lumen by angiography in one case. Regarding distal extent, authors defined A whose extent was proximal to diaphragm and B beyond it for convenience sake. There was one false negative case in CT among 16 cases which was diagnosed as dissecting aneurysm type IIIB by angiography and confirmed as type III surgically. One case was diagnosed as type IB by CT and as type IIIB by angiography and confirmed as type I surgically. Extent was more accurate in CT than angiography. One case was diagnosed as type II by CT but misdiagnosed as right atrial tumor by angiography. 4. Diagnostic sensitivities of CT and angiography in this study were 94% (15/16) respectively. CT was more advantageous in hemothorax, hemopericardium, hemomediastinum, unopacified false lumen, aortic wall calcification and getting information about mediastinum. In angiography aortic regurgitation and tear site and involvement of abdominal vessels could be observed.

  11. Inter-observer agreement and diagnostic accuracy of myocardial perfusion reserve quantification by cardiovascular magnetic resonance at 3 Tesla in comparison to quantitative coronary angiography.

    Science.gov (United States)

    Ikuye, Katharina; Buckert, Dominik; Schaaf, Lisa; Walcher, Thomas; Rottbauer, Wolfgang; Bernhardt, Peter

    2013-03-27

    Quantification of cardiovascular magnetic resonance (CMR) myocardial perfusion reserve (MPR) at 1.5 Tesla has been shown to correlate to invasive evaluation of coronary artery disease (CAD) and to yield good inter-observer agreement. However, little is known about quantitative adenosine-perfusion CMR at 3 Tesla and no data about inter-observer agreement is available. Aim of our study was to evaluate inter-observer agreement and to assess the diagnostic accuracy in comparison to quantitative coronary angiography (QCA). Fifty-three patients referred for coronary x-ray angiography were previously examined in a 3 Tesla whole-body scanner. Adenosine and rest perfusion CMR were acquired for the quantification of MPR in all segments. Two blinded and independent readers analyzed all images. QCA was performed in case of coronary stenosis. QCA data was used to assess diagnostic accuracy of the MPR measurements. Inter-observer agreement was high for all myocardial perfusion territories (ρ = 0.92 for LAD, ρ = 0.93 for CX and RCA perfused segments). Compared to QCA receiver-operating characteristics yielded an area under the curve of 0.78 and 0.73 for RCA, 0.66 and 0.69 for LAD, and 0.52 and 0.53 for LCX perfused territories. Inter-observer agreement of MPR quantification at 3 Tesla CMR is very high for all myocardial segments. Diagnostic accuracy in comparison to QCA yields good values for the RCA and LAD perfused territories, but moderate values for the posterior LCX perfused myocardial segments.

  12. Diagnostic accuracy of magnetic resonance angiography for detection of coronary artery disease: a systematic review and meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Di Leo, Giovanni [IRCCS Policlinico San Donato, Radiology Unit, San Donato Milanese (Italy); Fisci, Erica [Universita degli Studi di Genova, Scuola di Specializzazione in Radiodiagnostica, Genova (Italy); Secchi, Francesco [IRCCS Policlinico San Donato, Radiology Unit, San Donato Milanese (Italy); Universita degli Studi di Milano, PhD Course in Integrative Biomedical Research, Milan (Italy); Ali, Marco [Universita degli Studi di Milano, PhD Course in Integrative Biomedical Research, Milan (Italy); Ambrogi, Federico [Universita degli Studi di Milano, Department of Clinical Sciences and Community Health, Milan (Italy); Sconfienza, Luca Maria; Sardanelli, Francesco [IRCCS Policlinico San Donato, Radiology Unit, San Donato Milanese (Italy); Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, San Donato Milanese (Italy)

    2016-10-15

    To review the diagnostic performance of MR coronary angiography (MRCA) for coronary artery disease (CAD). Two independent reviewers searched on MEDLINE/EMBASE with the following inclusion criteria: 01/01/2000-03/23/2015 publication date; per-patient sensitivity/specificity for >50 % stenosis confirmed by conventional coronary angiography with raw data provided or retrievable; sample size >10. Quality was appraised using QUADAS2. Nine hundred eighteen studies were retrieved, 24 of them, including 1,638 patients, were selected. Using a bivariate model, the pooled sensitivity was 89 % (95 % confidence interval 86-92 %), the pooled specificity 72 % (63-79 %). Meta-regression did not show a significant impact on sensitivity/specificity for both year of publication and disease prevalence (p ≥ 0.114). Sensitivity of contrast-enhanced examinations (95 %, 90-97 %) was higher (p = 0.005) than that of unenhanced examinations (87 %, 83-90 %). Specificity of whole-heart acquisition mode (78 %, 72-84 %) was higher (p = 0.006) than that of targeted mode (57 %, 45-69 %). Specificity at 3 T (83 %, 69-92 %) was higher (p = 0.067) than that at 1.5 T (68 %, 60-76 %). Risk of bias and concerns regarding applicability were low. Sensitivity and specificity of MRCA for CAD were 89 % and 72 %, respectively. A specificity higher than 80 % may be obtained at 3 T. Whole-heart contrast-enhanced protocols should be preferred for a higher diagnostic performance. (orig.)

  13. 川崎病患儿冠状动脉的CT血管造影及磁共振血管造影%Computed tomography angiography and magnetic resonance angiography evaluate coronary artery in children with Kawasaki disease

    Institute of Scientific and Technical Information of China (English)

    胡喜红; 黄国英

    2014-01-01

    Kawasaki disease can affect the coronary arteries,including coronary artery dilation,aneurysm,stenosis and thrombus.Conventional coronary angiography is the gold standard for coronary artery evaluation,but there are risks associated with its invasive nature and with the exposure to contrast agents and radiation.With the rapid development,computed tomography angiography and magnetic resonance angiography become the noninvasive imaging modalities to evaluate the coronary artery.%川崎病容易累及冠状动脉,可导致冠状动脉扩张、冠状动脉瘤形成、狭窄或闭塞等.经导管冠状动脉血管造影是传统评价冠状动脉病变的方法,但其存在一定的侵入性.近年来CT和磁共振技术迅速发展,CT血管造影和磁共振血管造影逐渐成为评估冠状动脉病变的重要无创检查手段.

  14. The role of preoperative cerebral magnetic resonance angiography in the prevention of cerebral complications following cardiovascular surgery

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Masakazu; Sakai, Akira; Kodera, Koujirou; Sudo, Kyouichi; Oosawa, Mikio [Seirei Hamamatsu General Hospital, Shizuoka (Japan)

    1997-11-01

    Screening of carotid and intracranial artery diseases by magnetic resonance angiography (MRA) was performed in forty-one adult patients prior to elective cardiovascular surgery. In twenty patients (48.8%), MRA demonstrated significant cerebrovascular lesions: carotid or main cerebral artery stenosis in 7, diffuse cerebral arteriosclerotic change in 6, vertebral artery lesion in 5 and berry aneurysm in 2. Advanced age (over 70 years) and previous cerebrovascular events increased the incidence of cerebrovascular lesions on MRA. Forty patients underwent scheduled surgery under cardiopulmonary bypass, and pulsatile flow perfusion was used in patients in whom significant cerebrovascular lesions were demonstrated on MRA. One patient with aortic arch aneurysm was judged to be an unacceptable candidate for surgery in light of his marked diffuse arteriosclerotic lesions on MRA. In five patients, staged operation was performed from 10 to 30 days after cerebrovascular surgery (bypass surgery for internal carotid occlusion in 2, aneurysm clipping in 2, carotid endarterectomy in 1). Postoperative neurological complications occurred in one patient (2.5%). In conclusion, screening of carotid and intracranial artery diseases by MRA is a safe and useful method for evaluation of cerebrovascular lesions in patients with advanced age, previous cerebrovascular events and/or arteriosclerotic diseases. (author)

  15. Application of electrophysiological methods and magnetic resonance tomographic angiography in the differentiation between hemifacial spasm and Meige syndrome.

    Science.gov (United States)

    Huang, Chuyi; Miao, Suhua; Chu, Heling; Muheremu, Aikeremujiang; Wu, Jinting; Zhou, Rongsong; Zuo, Huancong; Ma, Yu

    2016-05-01

    Bilateral hemifacial spasm and Meige syndrome can be easily confused due to their similar clinical manifestation. Here, we aimed to investigate the application of electrophysiological methods and magnetic resonance tomographic angiography (MRTA) in the differentiation between hemifacial spasm and Meige syndrome. 10 patients with bilateral hemifacial spasm and 9 patients with Meige syndrome received electrophysiological monitoring of nerves. There were two males and eight females with bilateral hemifacial spasm, aged 16-58 years with a course of 5-54 months. For the patients with Meige syndrome, there were three males and six females, aged 51-68 years with a course of 12-36 months. All patients received conventional MRTA of the brain blood vessels before decompression. We found that all patients with Meige syndrome showed synchronous contraction of bilateral orbicularis oculi muscles and (or) burst discharge from orbicularis oris muscles in surface electromyography (sEMG). However, those with hemifacial spasm presented with bilaterally asynchronous burst discharge. Electromyography for patients with Meige syndrome did not record abnormal muscle response (AMR), but recorded AMR for those with bilateral hemifacial spasm. The offending vessels were compressed in patients with hemifacial spasm in MRTA, while MRTA results were generally negative for those with Meige syndrome. Combining sEMG and AMR detection in EMG and MRTA, bilateral hemifacial spasm can be differentiated from Meige syndrome with a reduction of misdiagnosis rate.

  16. Congenital aortic arch anomalies: diagnosis using contrast enhanced magnetic resonance angiography

    Institute of Scientific and Technical Information of China (English)

    ZHU Ming; ZHONG Yu-min; LI Yu-hua; SUN Ai-min; JIN Biao

    2005-01-01

    @@ Congenital aortic arch anomalies occur most commonly in children. The disease can be classified into three types: ① obstructive congenital abnormalities, including coarctation of aorta (CoA) and interruption of aortic arch (IAA); ② non-obstructive congenital abnormalities, including double aortic arch and others; ③ congenital shunt abnormalities, including different types of patent ductus arteriosus (PDA). Management of patients with congenital aortic arch anomalies relies on imaging. Routine imaging modalities, such as conventional X-ray plain film and transthoracic echocardiography (TTE), have been recently complemented by magnetic resonance imaging (MRI).

  17. Arterial occlusion sites on magnetic resonance angiography influence the efficacy of intravenous low-dose (0.6 mg/kg) alteplase therapy for ischaemic stroke.

    Science.gov (United States)

    Nakashima, T; Toyoda, K; Koga, M; Matsuoka, H; Nagatsuka, K; Takada, T; Naritomi, H; Minematsu, K

    2009-12-01

    To determine the predictors of efficacy, including magnetic resonance imaging information, for low-dose intravenous alteplase therapy for stroke patients. Seventy-eight patients were prospectively enrolled in a single Stroke Unit (SU) receiving alteplase at a dose of 0.6 mg/kg during the initial 27 months after its approval in Japan. Ischaemic changes and vascular lesions were identified using computed tomography, diffusion-weighted magnetic resonance imaging, and magnetic resonance angiography. Early ischaemic signs were assessed using the Alberta Stroke Program Early CT Score. The median baseline National Institutes of Health Stroke Scale score of 78 patients was 12. In 19 patients (24%), the National Institutes of Health Stroke Scale score improved by >or=8 points at 24 h. After multivariate adjustment, occlusion at the internal carotid artery (odds ratio 11.82, 95% confidence interval 1.73-142.74), Alberta Stroke Program Early CT Score on diffusion-weighted imaging Stroke Scale score (1.24, 1.08-1.47, per 1-point decrease) were inversely correlated with early improvement. Four patients (5%) had symptomatic intracranial haemorrhage. At 3 months, 76 patients (98%) survived, and 36 of 78 patients (46%) overall, but only two of 19 patients (11%) with internal carotid artery occlusion, had a favourable functional outcome, corresponding to a modified Rankin scale score Stroke Program Early CT Score on diffusion-weighted imaging studies using an alteplase dose of 0.9 mg/kg. However, patients with occlusion at the internal carotid artery did not respond to this low-dose alteplase therapy.

  18. Assessment of pulmonary venous stenosis after radiofrequency catheter ablation for atrial fibrillation by magnetic resonance angiography: a comparison of linear and cross-sectional area measurements

    Energy Technology Data Exchange (ETDEWEB)

    Tintera, Jaroslav; Porod, Vaclav; Rolencova, Eva; Fendrych, Pavel [Institute for Clinical and Experimental Medicine, Department of Radiology, Prague 4 (Czech Republic); Cihak, Robert; Mlcochova, Hanka; Kautzner, Josef [Institute for Clinical and Experimental Medicine, Department of Cardiology, Prague 4 (Czech Republic)

    2006-12-15

    One of the recognised complications of catheter ablation is pulmonary venous stenosis. The aim of this study was to compare two methods of evaluation of pulmonary venous diameter for follow-up assessment of the above complication: (1) a linear approach evaluating two main diameters of the vein, (2) semiautomatically measured cross-sectional area (CSA). The study population consists of 29 patients. All subjects underwent contrast-enhanced magnetic resonance angiography (CeMRA) of the pulmonary veins (PVs) before and after the ablation; 14 patients were also scanned 3 months later. PV diameter was evaluated from two-dimensional multiplanar reconstructions by measuring either the linear diameter or CSA. A comparison between pulmonary venous CSA and linear measurements revealed a systematic difference in absolute values. This difference was not significant when comparing the relative change CSA and quadratic approximation using linear extents (linear approach). However, a trend towards over-estimation of calibre reduction was documented for the linear approach. Using CSA assessment, significant PV stenosis was found in ten PVs (8%) shortly after ablation. Less significant PV stenosis, ranging from 20 to 50% was documented in other 18 PVs (15%). CeMRA with CSA assessment of the PVs is suitable method for evaluation of PV diameters. (orig.)

  19. Qualitative assessment of contrast-enhanced magnetic resonance angiography using breath-hold and non-breath-hold techniques in the portal venous system

    Science.gov (United States)

    Goo, Eun-Hoe; Kim, Sun-Ju; Dong, Kyung-Rae; Kim, Kwang-Choul; Chung, Woon-Kwan

    2016-09-01

    The purpose of this study is to evaluate the image quality in delineation of the portal venous systems with two different methods, breath-hold and non-breath-hold by using the 3D FLASH sequence. We used a 1.5 T system to obtain magnetic resonance(MR)images. Arterial and portal phase 3D FLASH images were obtained with breath-hold after a bolus injection of GD-DOTA. The detection of PVS on the MR angiograms was classified into three grades. First, the angiograms of the breath-hold method showed well the portal vein, the splenic vein and the superior mesenteric vein systems in 13 of 15 patients (86%) and the inferior mesenteric vein system in 6 of 15 patients (40%), Second, MR angiograms of the non-breath-hold method demonstrated the PVS and the SMV in 12 of 15 patients (80%) and the IMV in 5 of 15 patients (33%). Our study showed contrast-enhanced 3D FLASH MR angiography, together with the breath-hold technique, may provide reliable and accurate information on the portal venous system.

  20. Diagnosis of intracranial occlusive vascular disease and evaluation of extracranial-intracranial (EC/IC) arterial bypass using three-dimensional magnetic resonance angiography

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Takashi; Houkin, Kiyohiro; Kamiyama, Hiroyasu; Iwasaki, Yoshinobu; Abe, Hiroshi (Hokkaido Univ., Sapporo (Japan). School of Medicine); Kawaguchi, Susumu; Kashiwabara, Takeshi; Koiwa, Mitsuyuki

    1993-01-01

    The three-dimensional time-of-flight (TOF) magnetic resonance angiograms (MRA) were studied to evaluate its accuracy in the assessment of the intracranial carotid occlusive lesions, collateral circulation and also the patency of extracranial-intracranial (EC/IC) arterial bypass surgery. All occlusive lesions of the intracranial major arteries seen in conventional angiograms were revealed clearly with MRA. However MRA had its practical limitation in the evaluation of the leptomeningeal anastomosis (collateral circulation) probably due to the deterioration of contrast in its slow flow and saturation effect of the magnetization. In addition to that, MRA often exaggerated the severity of the stenotic lesions, mostly in severe cases. The postoperative state of collateral flow and the patency of EC/IC bypass could be evaluated as properly with MRA as with conventional angiography, although MRA was limited in spatial resolution and evaluation of flow direction. In conclusion, MRA was considered to be a reliable non-invasive modality as a screening examination for the evaluation of the carotid occlusive disease and as the follow-up study of the post-operative patients with EC/IC bypass surgery. (author).

  1. The diagnosis of intracranial carotid occlusive disease and the evaluation of extracranial-intracranial arterial bypass using three-dimensional magnetic resonance angiography

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Takeshi; Houkin, Kiyohiro; Kamiyama, Hiroyasu; Iwasaki, Yoshinobu; Abe, Hiroshi (Hokkaido Univ., Sapporo (Japan). School of Medicine); Koiwa, Mitsuyuki; Kawaguchi, Susumu; Kashiwaba, Takeshi

    1993-02-01

    Three-dimensional time-of-flight (TOF) magnetic resonance angiograms (MRA) were studied in order to evaluate their accuracy in the assessment of intracranial carotid occlusive lesions, collateral circulation, and the usefulness of extracranial-intracranial (EC/IC) arterial bypass surgery. All occlusive lesions of the intracranial major arteries seen in conventional angiograms were clearly revealed with MRA. However, MRA had a practical limitation in the evaluation of leptomeningeal anastomosis (collateral circulation), probably because of the deterioration of the contrast in its slow flow and because of the saturation effect of the magnetization. In addition, MRA often exaggerated the severity of the stenotic lesions, mostly in severe cases. The post-operative state of the collateral flow and the usefulness of EC/IC bypass could be evaluated as properly with MRA as with conventional angiography, although MRA was limited in its spatial resolution and in its evaluation of the flow direction. In conclusion, MRA was considered to be a reliable, non-invasive modality for use as a screening examination for the evaluation of carotid occlusive disease and as a follow-up, post-operative study of patients who have received EC/IC bypass surgery. (author).

  2. Frequency of Intracranial Aneurysms Determined by Magnetic Resonance Angiography in Children (Mean Age 16) Having Operative or Endovascular Treatment of Coarctation of the Aorta (Mean Age 3).

    Science.gov (United States)

    Donti, Andrea; Spinardi, Luca; Brighenti, Maurizio; Faccioli, Luca; Leoni, Chiara; Fabi, Marianna; Trossello, Marco P; Gargiulo, Gaetano D; Bonvicini, Marco

    2015-08-15

    Coarctation of the aorta (CofA) has been associated with an increased risk of intracranial aneurysm (IA). This magnetic resonance angiography (MRA) study investigates the prevalence of IAs in 80 children treated in early life for CofA. MRA was performed at mean age of 15.7 ± 7.1 years, and surgical or endovascular treatment for CofA occurred at a mean age of 2.6 ± 4.4 years. No IA was found. In contrast with earlier findings in adult patients with late treatment for CofA, this first systematic study of very early treated patients for CofA failed to confirm the association between CofA and IAs. Our results call the abnormal developmental relation between CofA and IAs into question and suggest that modifiable risk factors like hypertension may be responsible for IA development in patients with CofA with adult diagnosis and treatment. In conclusion, our data suggest that early treatment of CofA can reduce the formation of IAs in children so as to make MRA screening less valuable in this young population.

  3. Contrast-enhanced magnetic resonance angiography for the detection of crossing renal vessels in children with symptomatic ureteropelvic junction obstruction: comparison with operative findings

    Energy Technology Data Exchange (ETDEWEB)

    Calder, Alistair D.; Hiorns, Melanie P.; Olsen, Oystein E. [Hospital for Children NHS Trust, Department of Radiology, London (United Kingdom); Abhyankar, Aruna; Mushtaq, Imran [Hospital for Children NHS Trust, Department of Urology, London (United Kingdom)

    2007-04-15

    Crossing renal vessels (CRV) are associated with ureteropelvic junction (UPJ) obstruction, particularly when presentation is beyond the neonatal period. Their presence may influence surgical management. To evaluate the accuracy of contrast-enhanced magnetic resonance angiography (CE-MRA) in the identification of CRV in children requiring surgical treatment of symptomatic UPJ obstruction, against a gold standard of laparoscopic or open surgical findings. We reviewed CE-MRA studies (3-D T2-weighted turbo spin-echo and multiphase 3-D spoiled gradient echo following intravenous gadolinium administration) of 14 children, age range 6-15 years, performed prior to surgery for suspected CRV-related UPJ obstruction. Consensus reviews of the CE-MRA studies were compared with surgical findings. CE-MRA demonstrated CRV at the level of the obstruction in nine and no crossing vessels in five children. These were all verified intraoperatively ({chi}{sup 2} = 14.0; P < 0.001). In eight of the nine patients with CRV there was no evidence of intrinsic obstruction at surgery. In the remaining patient there was fibrosis of the upper ureter. CE-MRA is an accurate means of identifying CRV in children older than 6 years with symptomatic UPJ obstruction. (orig.)

  4. Three-Dimensional Time-of-Flight Magnetic Resonance Angiography Detection of Duplication of the Vertebral Artery in a Large Chinese Population.

    Science.gov (United States)

    Li, Shuhua; Li, Yunyun; Bai, Min; Zhang, Chuanchen

    2016-10-17

    BACKGROUND The aim of this study was to investigate duplication of the vertebral artery (VA) using three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA) in a large study population to further our understanding of vascular variations. MATERIAL AND METHODS A retrospective analysis of 3D TOF-MRA data in 12 826 cases was performed. The occurrence rate of VA duplication was calculated and accompanied vascular anomalies were recoded. RESULTS Twenty-one VA duplication patients were found, with an occurrence rate of 0.164%; 12 of them had left VA duplication with 2 branches initially arising from the aortic arch and left subclavian artery; 9 of them were right VA duplication with the branches originating from the right subclavian artery. In the 21 cases, 11 had other vascular abnormalities. CONCLUSIONS VA duplication is very rare and often associated with other vascular abnormalities. 3D TOF-MRA can accurately display the duplication variation. Better understanding of the variation is instrumental for disease diagnosis, interventional therapy, and surgical operation.

  5. Three-Dimensional Time-of-Flight Magnetic Resonance Angiography Detection of Duplication of the Vertebral Artery in a Large Chinese Population

    Science.gov (United States)

    Li, Shuhua; Li, Yunyun; Bai, Min; Zhang, Chuanchen

    2016-01-01

    Background The aim of this study was to investigate duplication of the vertebral artery (VA) using three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA) in a large study population to further our understanding of vascular variations. Material/Methods A retrospective analysis of 3D TOF-MRA data in 12 826 cases was performed. The occurrence rate of VA duplication was calculated and accompanied vascular anomalies were recoded. Results Twenty-one VA duplication patients were found, with an occurrence rate of 0.164%; 12 of them had left VA duplication with 2 branches initially arising from the aortic arch and left subclavian artery; 9 of them were right VA duplication with the branches originating from the right subclavian artery. In the 21 cases, 11 had other vascular abnormalities. Conclusions VA duplication is very rare and often associated with other vascular abnormalities. 3D TOF-MRA can accurately display the duplication variation. Better understanding of the variation is instrumental for disease diagnosis, interventional therapy, and surgical operation. PMID:27749814

  6. Ankle Brachial Index <0.9 Underestimates the Prevalence of Peripheral Artery Occlusive Disease Assessed with Whole-Body Magnetic Resonance Angiography in the Elderly

    Energy Technology Data Exchange (ETDEWEB)

    Wikstroem, J.; Hansen, T.; Johansson, L.; Lind, L.; Ahlstroem, H. [Dept. of Radiology and Dept. of Medical Sciences, Uppsala Univ. Hospital, Uppsala (Sweden)

    2008-03-15

    Background: Whole-body magnetic resonance angiography (WBMRA) permits noninvasive vascular assessment, which can be utilized in epidemiological studies. Purpose: To assess the relation between a low ankle brachial index (ABI) and high-grade stenoses in the pelvic and leg arteries in the elderly. Material and Methods: WBMRA was performed in a population sample of 306 subjects aged 70 years. The arteries below the aortic bifurcation were graded after the most severe stenosis according to one of three grades: 0-49% stenosis, 50-99% stenosis, or occlusion. ABI was calculated for each side. Results: There were assessable WBMRA and ABI examinations in 268 (right side), 265 (left side), and 258 cases (both sides). At least one {>=}50% stenosis was found in 19% (right side), 23% (left side), and 28% (on at least one side) of the cases. The corresponding prevalences for ABI <0.9 were 4.5%, 4.2%, and 6.6%. An ABI cut-off value of 0.9 resulted in a sensitivity, specificity, and positive and negative predictive value of 20%, 99%, 83%, and 84% on the right side, and 15%, 99%, 82%, and 80% on the left side, respectively, for the presence of a {>=} 50% stenosis in the pelvic or leg arteries. Conclusion: An ABI <0.9 underestimates the prevalence of peripheral arterial occlusive disease in the general elderly population.

  7. Time-resolved magnetic resonance angiography (MRA) at 3.0 Tesla for evaluation of hemodynamic characteristics of vascular malformations: description of distinct subgroups.

    Science.gov (United States)

    Hammer, Simone; Uller, Wibke; Manger, Florentine; Fellner, Claudia; Zeman, Florian; Wohlgemuth, Walter A

    2017-01-01

    Quantitative evaluation of hemodynamic characteristics of arteriovenous and venous malformations using time-resolved magnetic resonance angiography (MRA) at 3.0 Tesla. Time-resolved MRA with interleaved stochastic trajectories (TWIST) at 3.0 Tesla was studied in 83 consecutive patients with venous malformations (VM) and arteriovenous malformations (AVM). Enhancement characteristics were calculated as percentage increase of signal intensity above baseline over time. Maximum percentage signal intensity increase (signalmax), time intervals between onset of arterial enhancement and lesion enhancement (tonset), and time intervals between beginning of lesion enhancement and maximum percentage of lesion enhancement (tmax) were analyzed. All AVMs showed a high-flow hemodynamic pattern. Two significantly different (p Tesla provides hemodynamic characterization of vascular malformations. VMs can be subclassified into two hemodynamic subgroups due to presence or absence of AVFs. • Time-resolved MRA at 3.0 Tesla provides quantitative hemodynamic characterization of vascular malformations. • Malformations significantly differ in time courses of enhancement and signal intensity increase. • AVMs show a distinctive high-flow hemodynamic pattern. • Two significantly different types of VMs emerged: VMs with and without AVFs.

  8. Cerebral blood flow volume measurements of the carotid artery and ipsilateral branches using two-dimensional phase-contrast magnetic resonance angiography

    Institute of Scientific and Technical Information of China (English)

    Gang Guo; Yonggui Yang; Weiqun Yang

    2011-01-01

    The optimal velocity encoding of phase-contrast magnetic resonance angiography (PC MRA) in measuring cerebral blood flow volume (BFV) ranges from 60 to 80 cm/s. To verify the accuracy of two-dimensional (2D) PC MRA, the present study localized the region of interest at blood vessels of the neck using PC MRA based on three-dimensional time-of-flight sequences, and the velocity encodingwas set to 80 cm/s. Results of the measurements showed that the error rate was 7.0 ± 6.0%in the estimation of BFV in the internal carotid artery, the external carotid artery and the ipsilateralcommon carotid artery. There was no significant difference, and a significant correlation in BFV between internal carotid artery + external carotid artery and ipsilateral common carotid artery. Inaddition, the BFV of the common carotid artery was correlated with that of the ipsilateral internal carotid artery. The main error was attributed to the external carotid artery and its branches. Therefore,after selecting the appropriate scanning parameters and protocols, 2D PC MRA is more accuratein the determination of BFV in the carotid arteries.

  9. The evaluation of vertebrobasilar artery system in neuro-Behçet and Behçet disease using magnetic resonance angiography.

    Science.gov (United States)

    Kose, Evren; Kamisli, Suat; Dogan, Metin; Tasolar, Sevgi; Kahraman, Ayşegül; Oztanir, Mustafa Namik; Sener, Serpil

    2014-07-01

    The aim of this study is the evaluation of the vertebrobasilar artery system in patients with Behçet's and Neuro-Behçet's disease. For this aim; 20 adults with clinically diagnosed Behcet's disease, 20 adults with Neuro-Behçet's disease, and 19 age- and gender-matched controls were examined by magnetic resonance angiography (MRA). During MRA, diameters of left vertebral artery (LVA), right vertebral artery (RVA), basilar artery (BA), and proximal segment (P1) of posterior cerebral artery between origin and junction with the posterior communicating artery were measured. In all groups, LVA was dominant than RVA (P < 0.05). The diameters of BA and right P1 of Neuro-Behçet's disease were larger than the other groups (P < 0.05). In addition, the diameters of left P1 of Neuro-Behçet's disease were larger but not statistically significant. There is no difference between the groups in terms of gender. Behçet's disease can affect vascular structures; therefore vertebrobasilar artery system should be examined in patients with Behçet's and Neuro-Behçet's disease.

  10. Time-resolved magnetic resonance angiography (MRA) at 3.0 Tesla for evaluation of hemodynamic characteristics of vascular malformations: description of distinct subgroups

    Energy Technology Data Exchange (ETDEWEB)

    Hammer, Simone; Fellner, Claudia; Wohlgemuth, Walter A. [University Hospital Regensburg, Department of Radiology, Regensburg (Germany); Uller, Wibke [Boston Children' s Hospital and Harvard Medical School, Division of Vascular and Interventional Radiology, Boston, MA (United States); University Hospital Regensburg, Department of Radiology, Regensburg (Germany); Manger, Florentine [University Hospital Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Zeman, Florian [University Hospital Regensburg, Center for Clinical Trials, Regensburg (Germany)

    2017-01-15

    Quantitative evaluation of hemodynamic characteristics of arteriovenous and venous malformations using time-resolved magnetic resonance angiography (MRA) at 3.0 Tesla. Time-resolved MRA with interleaved stochastic trajectories (TWIST) at 3.0 Tesla was studied in 83 consecutive patients with venous malformations (VM) and arteriovenous malformations (AVM). Enhancement characteristics were calculated as percentage increase of signal intensity above baseline over time. Maximum percentage signal intensity increase (signal{sub max}), time intervals between onset of arterial enhancement and lesion enhancement (t{sub onset}), and time intervals between beginning of lesion enhancement and maximum percentage of lesion enhancement (t{sub max}) were analyzed. All AVMs showed a high-flow hemodynamic pattern. Two significantly different (p < 0.001) types of venous malformations emerged: VMs with arteriovenous fistulas (AVF) (median signal{sub max} 737 %, IQR [interquartile range] = 511 - 1182 %; median t{sub onset} 5 s, IQR = 5 - 10 s; median t{sub max} 35 s, IQR = 26 - 40 s) and without AVFs (median signal{sub max} 284 %, IQR = 177-432 %; median t{sub onset} 23 s, IQR = 15 - 30 s; median t{sub max} 60 s, IQR = 55 - 75 s). Quantitative evaluation of time-resolved MRA at 3.0 Tesla provides hemodynamic characterization of vascular malformations. VMs can be subclassified into two hemodynamic subgroups due to presence or absence of AVFs. (orig.)

  11. Catheter Angiography

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

  12. 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 ...

  13. Three-dimensional reconstructed magnetic resonance imaging for diagnosing persistent left superior vena cava. Comparison with magnetic resonance angiography and plain chest radiography

    Energy Technology Data Exchange (ETDEWEB)

    Koito, Hitoshi; Suzuki, Junichi; Ohkubo, Naohiko; Ishiguro, Yuka; Iwasaka, Toshiji; Inada, Mitsuo; Nakano, Yoshihisa [Kansai Medical Univ., Moriguchi, Osaka (Japan)

    1996-09-01

    The usefulness of low-cost, three-dimensional (3D) images reconstructed from magnetic resonance (MR) imaging for investigating persistent left superior vena cava was assessed and compared to the diagnostic accuracy of chest radiography. MR imaging by the spin-echo technique and MR angiography were performed in 10 patients with this anomaly diagnosed previously by contrast echocardiography and radionuclide angiocardiography. Four patients had complicating cardiac anomalies, one with postoperative atrial septal defect, one with postoperative ventricular septal defect, one with atrial septal defect and partial anomalous pulmonary venous return, and one with aortic coarctation and patent ductus arteriosus. Multisectional and multiphasic MR images were used for the 3D-reconstruction of the cardiovascular and mediastinal structures with a NeXT workstation and a 3D-kit. The 3D-reconstructed MR imaging clearly showed the persistent left superior vena cava and the anatomical relationship with the other cardiovascular and mediastinal structures in all 10 patients. Vascular shadows were observed outside the upper left border of the aortic arch on the chest radiographs in seven patients, and the 3D-reconstructed MR images revealed these shadows to be compatible with superior caval vein. The ratios of the diameter between the left and right superior venae cavae with and without the left innominate vein were 0.63{+-}0.14 (mean{+-}SD) and 0.94{+-}0.08, respectively. Three-dimensional reconstructed MR imaging is a useful method for recognizing persistent left superior vena cava and precise examination of the chest radiographs often allowed detection of the vascular shadows caused by this anomaly. (author)

  14. 磁共振血管造影在临床应用的新进展%Magnetic Resonance Angiography in Clinical Application

    Institute of Scientific and Technical Information of China (English)

    董军; 孙洪珍; 吴树冰

    2013-01-01

      本文介绍了最新发展的无创性磁共振血管造影检查方法,就其成像原理、应用技术及磁共振造影在血管影像诊断方面的临床应用及其评价进行综述。%This paper introduces the latest development of non-invasive magnetic resonance angiography (MRA) method, the imaging principle, application technology and MRA in vascular imaging diagnosis of clinical application and evaluation were reviewed in this article.

  15. Magnetic resonance angiography of the carotid arteries: comparison of unenhanced and contrast enhanced techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Harald; Nikolaou, Konstantin; Reiser, Maximilian F. [Ludwig Maximilians University, Department of Clinical Radiology, University Hospitals Munich, Grosshadern Campus, Munich (Germany); Runge, Val M. [University of Texas Medical Branch, Department of Radiology, Galveston, TX (United States); Morelli, John N.; Williams, Kenneth D.; Naul, L.G. [Scott and White Memorial Hospital, Department of Radiology, Temple, TX (United States); Wintersperger, Bernd J. [Ludwig Maximilians University, Department of Clinical Radiology, University Hospitals Munich, Grosshadern Campus, Munich (Germany); University of Toronto, Department of Medical Imaging, UHN, MSH and WCH, Toronto (Canada)

    2011-08-15

    To compare different techniques for carotid imaging including contrast-enhanced, unenhanced and dynamic techniques to find an alternative to contrast-enhanced MRA. 43 patients referred for imaging of the carotids were enrolled in this IRB-approved study. Imaging included dark-blood, time-of-flight, ECG-gated SSFP and dynamic and static contrast-enhanced MRA. Two radiologists evaluated all datasets in terms of image quality (vessel lumen, signal homogeneity, diagnostic confidence, preferred technique) on a four-point Likert-scale and in measuring the vessel area. Of the 43 included patients the first 8 subjects served for protocol optimisation and 4 individuals discontinued the examination. Thus 31 datasets served for evaluation. CE-MRA revealed best results for delineation of vessel lumen, signal homogeneity and diagnostic confidence with values of 3.61, 3.42 and 3.77. It was also rated as the most preferred technique. SSFP-MRA was rated second in all categories with values of 3.1, 2.9 and 3.11. This unenhanced technique was the only one showing non-significantly different results in quantitative analysis. SSFP-MRA, an unenhanced form of MRA, represents an alternative to CE-MRA, particularly in patients where administration of gadolinium for CE-MRA may be contraindicated. In contrast to other techniques, SSFP-MRA serves with not significant different results compared to standard CE-MRA. (orig.)

  16. Direct Assessment of Wall Shear Stress by Signal Intensity Gradient from Time-of-Flight Magnetic Resonance Angiography.

    Science.gov (United States)

    Han, Kap-Soo; Lee, Sang Hyuk; Ryu, Han Uk; Park, Se-Hyoung; Chung, Gyung-Ho; Cho, Young I; Jeong, Seul-Ki

    2017-01-01

    The aim of the study was to calculate the arterial wall signal intensity gradient (SIG) from time-of-flight MR angiography (TOF-MRA) and represent arterial wall shear stress. We developed a new algorithm that uses signal intensity (SI) of a TOF-MRA to directly calculate the signal intensity gradient (SIG). The results from our phantom study showed that the TOF-MRA SIG could be used to distinguish the magnitude of blood flow rate as high (mean SIG ± SD, 2.2 ± 0.4 SI/mm for 12.5 ± 2.3 L/min) and low (0.9 ± 0.3 SI/mm for 8.5 ± 2.6 L/min) in vessels (p SIG values were highly correlated with various flow rates (β = 0.96, p SIG was greater than 0.8 in each section at the carotid artery (p SIG and thereby the WSS. Thus, the TOF-MRA SIG can provide clinicians with an accurate and efficient screening method for making rapid decisions on the risk of vascular disease for a patient in clinical practice.

  17. Space time relationship in continuously moving table method for large FOV peripheral contrast-enhanced magnetic resonance angiography

    Science.gov (United States)

    Sabati, M.; Lauzon, M. L.; Frayne, R.

    2003-09-01

    Data acquisition using a continuously moving table approach is a method capable of generating large field-of-view (FOV) 3D MR angiograms. However, in order to obtain venous contamination-free contrast-enhanced (CE) MR angiograms in the lower limbs, one of the major challenges is to acquire all necessary k-space data during the restricted arterial phase of the contrast agent. Preliminary investigation on the space-time relationship of continuously acquired peripheral angiography is performed in this work. Deterministic and stochastic undersampled hybrid-space (x, ky, kz) acquisitions are simulated for large FOV peripheral runoff studies. Initial results show the possibility of acquiring isotropic large FOV images of the entire peripheral vascular system. An optimal trade-off between the spatial and temporal sampling properties was found that produced a high-spatial resolution peripheral CE-MR angiogram. The deterministic sampling pattern was capable of reconstructing the global structure of the peripheral arterial tree and showed slightly better global quantitative results than stochastic patterns. Optimal stochastic sampling patterns, on the other hand, enhanced small vessels and had more favourable local quantitative results. These simulations demonstrate the complex spatial-temporal relationship when sampling large FOV peripheral runoff studies. They also suggest that more investigation is required to maximize image quality as a function of hybrid-space coverage, acquisition repetition time and sampling pattern parameters.

  18. Total-body 3D magnetic resonance angiography influences the management of patients with peripheral arterial occlusive disease

    Energy Technology Data Exchange (ETDEWEB)

    Goyen, Mathias; Herborn, Christoph U.; Debatin, Joerg F. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany); Kroeger, Knut [University Hospital Essen, Department of Angiology, Essen (Germany); Ruehm, Stefan G. [David Geffen School of Medicine at UCLA, Department of Radiology, Los Angeles, CA (United States)

    2006-03-15

    High-resolution total-body 3D MR angiography (MRA) has recently become available, revealing additional clinically relevant disease in patients with peripheral arterial occlusive disease (PAOD). However, the actual impact of total-body MRA on patient management in patients with PAOD has not been investigated so far. Two hundred forty-nine consecutive patients with angiographically proven PAOD were prospectively examined by means of contrast-enhanced total-body 3D MRA on a 1.5-T MR scanner. All correlative imaging studies performed within 60 days of total-body MRA were included in the efficacy analysis. Additional clinically relevant disease (luminal narrowing >50%, aneurysmal changes or dissections) was found in 73 segments (52 patients), including the renal arteries (36 segments), carotid arteries (28 segments), subclavian arteries (four segments) and abdominal aortic aneurysms (AAA) (five segments). Of the 73 segments, 36 were deemed necessary for further investigation by means of focused MRA examinations; the diagnosis was confirmed in all cases. Within the 60-day follow-up period, interventional or surgical therapy outside the peripheral arterial tree was performed in nine patients (11 segments), including carotid endatherectomy and renal artery angioplasty. The outlined total-body 3D MRA approach permits a comprehensive evaluation of the arterial system in patients with atherosclerosis and does indeed have an impact on patient management in patients with PAOD. (orig.)

  19. The role of cardiovascular magnetic resonance imaging and computed tomography angiography in suspected non-ST-elevation myocardial infarction patients : Design and rationale of the CARdiovascular Magnetic rEsoNance imaging and computed Tomography Angiography (CARMENTA) trial

    NARCIS (Netherlands)

    Smulders, Martijn W.; Kietselaer, Bastiaan L. J. H.; Das, Marco; Wildberger, Joachim E.; Crijns, Harry J. G. M.; Veenstra, Leo F.; Brunner-La Rocca, Hans-Peter; van Dieijen-Visser, Marja P.; Mingels, Alma M. A.; Dagnelie, Pieter C.; Post, Mark J.; Gorgels, Anton P. M.; van Asselt, Antoinette D. I.; Vogel, Gaston; Schalla, Simon; Kim, Raymond J.; Bekkers, Sebastiaan C. A. M.

    2013-01-01

    Background Although high-sensitivity cardiac troponin (hs-cTn) substantially improves the early detection of myocardial injury, it lacks specificity for acute myocardial infarction (MI). In suspected non-ST-elevation MI, invasive coronary angiography (ICA) remains necessary to distinguish between ac

  20. Angiorressonância magnética do crânio: revisão de 100 casos Magnetic resonance angiography of the brain: review of 100 cases

    Directory of Open Access Journals (Sweden)

    Leonardo Portugal Guimarães Amaral

    2004-06-01

    Full Text Available Neste trabalho foram analisados, retrospectivamente, os exames de 100 pacientes que se submeteram a angiografia por ressonância magnética (angio-RM do crânio com diferentes indicações clínicas. Os objetivos deste trabalho foram discutir as vantagens e desvantagens da técnica 3D TOF em exames de angio-RM cerebral e verificar as principais indicações de angio-RM na avaliação das lesões vasculares intracranianas e a freqüência dos principais achados nestes exames. As principais indicações para a realização de angio-RM neste trabalho foram cefaléia (n = 29, acidente vascular encefálico (n = 14 e ataque isquêmico transitório (n = 11. Em 11 casos não havia indicação clínica e os demais tiveram indicações diversas. Cinqüenta e dois por cento dos exames apresentaram alguma alteração. Os principais achados foram estenose vascular (n = 30, aneurisma (n = 10, variações anatômicas (n = 6, malformações vasculares (n = 4 e trombose dos seios durais (n = 2. A técnica 3D TOF, única utilizada neste trabalho, mostrou-se eficiente na maioria dos casos, com um tempo relativamente curto para sua aquisição. Como desvantagem, não se mostra eficaz para cobrir grandes volumes.In this study we reviewed the scans of 100 patients submitted to magnetic resonance angiography (MR angiography of the brain for different clinical indications. The objectives of the study were to discuss the advantages and disadvantages of the 3D TOF in cerebral MR angiography, to review the main indications of MR angiography in the evaluation of intracranial vascular lesions, and to assess the frequency of the most important findings. The main indications for MR angiography were headache (n = 29, stroke (n = 14, transient ischemic attack (n = 11 and other causes (n = 35. In 11 patients the clinical indication could not be recovered from the patients records. Fifty two percent of the exams showed abnormalities. The main findings were vascular stenosis (n

  1. Carotid artery stenosis with a high-intensity signal plaque on time-of-flight magnetic resonance angiography and association with evidence of intraplaque hypoxia.

    Science.gov (United States)

    Ogata, Atsushi; Kawashima, Masatou; Wakamiya, Tomihiro; Nishihara, Masashi; Masuoka, Jun; Nakahara, Yukiko; Ebashi, Ryo; Inoue, Kohei; Takase, Yukinori; Irie, Hiroyuki; Abe, Tatsuya

    2017-06-01

    OBJECTIVE Hypoxia induces angiogenesis and plays a major role in the progression of carotid plaques. During carotid intervention, plaques with high-intensity signals on time-of-flight (TOF) magnetic resonance angiography (MRA) often cause ischemic stroke and embolic complications. However, the role of intraplaque hypoxia before carotid endarterectomy (CEA) and carotid artery stenting is not presently understood. In this study the authors aimed to investigate the relationship between intraplaque hypoxia and MRA findings. METHODS Nineteen consecutive patients with 20 carotid artery stenoses who underwent CEA at Saga University Hospital between August 2008 and December 2014 were enrolled in the study. The expressions of hypoxia-inducible transcription factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) were analyzed by immunohistochemical analysis. In addition, the relationship between the findings on TOF MRA and pathology for the carotid plaques was analyzed. RESULTS High-intensity plaques on TOF MRA showed higher expression levels of HIF-1α (p = 0.015) and VEGF (p = 0.007) compared with isointensity plaques. The rate of intraplaque hemorrhage (IPH) on TOF MRA was also significantly higher in the high-intensity plaques than in the isointensity plaques (p = 0.024). Finally, the mean number of neovessels was significantly higher in those without plaque hemorrhage than in those with plaque hemorrhage (p = 0.010). CONCLUSIONS Plaques with high-intensity signals on TOF MRA were associated with IPH and evidence of intraplaque hypoxia. This fact may represent an opportunity to establish novel therapeutic agents targeting intraplaque hypoxia.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-15

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

  3. Combination of Magnetic Resonance Angiography and Computational Fluid Dynamics May Predict the Risk of Stroke in Patients with Asymptomatic Carotid Plaques

    Science.gov (United States)

    Jia, Qian; Liu, Hongbin; Li, Yanping; Wang, Xiaoxi; Jia, Jinju; Li, Yuying

    2017-01-01

    Background Atherosclerosis plaques in the carotid arteries frequently have been found in patients with stroke. However, the pathogenesis of carotid plaque from asymptomatic to cerebrovascular events is a complex process which is still not completely understood. We aimed to investigate the prognosis of asymptomatic carotid atherosclerotic plaques by use of magnetic resonance angiography (MRA) combined with computational fluid dynamics (CFD). Material/Methods We prospectively studied a cohort of 228 participants (mean age 59.21±8.48) with asymptomatic carotid atherosclerotic plaques; mean follow-up duration was 1147.56±224.84 days. Plaque morphology parameters were obtained by MRA analysis. Lumen area (LA) and total vessel area (TVA) were measured, and wall area (WA=TVA−LA) and normalized wall area index (NWI=WA/TVA) were calculated. CFD analysis was performed to evaluate hemodynamic characteristics, including wall pressure (WP) and wall shear stress (WSS). Independent risk factors for stroke were obtained by Cox regression analysis. The area under the curve (AUC) of receiver operator characteristic (ROC) and Z-statistic test were used to evaluate risk factors. Results Logistics regression analysis showed NWI (OR: 3.472, 95% CI: 2.943–4.096, P=0.11) and WSS (OR: 6.974, 95% CI: 1.070–45.453, P=0.42) were independent risk factors of stroke for patients with asymptomatic carotid plaques. The area under the ROC curve values for WSS, NWI, and WSS+NWI were 0.772, 0.798, and 0.903, respectively. Conclusions The combination of plaque morphology characteristics NWI and hemodynamic parameter WSS may predict the risk of stroke in patients with asymptomatic carotid plaques. PMID:28126983

  4. MR angiography with Vasovist

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-12-15

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

  5. Iohexol, ioxaglate and iopamidol in coronary angiography. A double-blind comparative study of 300 patients.

    Science.gov (United States)

    Soiva, M; Hekali, P; Keto, P; Karumo, J; Salonen, O; Heikkilä, J

    1991-05-01

    A randomized, double-blind study was carried out in 300 consecutive coronary angiography examinations to investigate the clinical safety of three low osmolar contrast media, iohexol 300, ioxaglate 320 and iopamidol 300, and the electrocardiographic changes that occurred with them. The ECG from electrode V5/V6 or AVF and intra-arterial pressure were monitored continuously, and recorded before and after the first contrast injections into the left and right coronary arteries. Of the variables tested, no statistically significant changes occurred in systolic arterial pressure, PR interval or ventricular extrasystole. The QT interval increased in the ioxaglate group (p = 0.001). Heart rate decreased in all groups, but slightly less in the ioxaglate group than in the iopamidol group (p = 0.02). The ST segment depression (mean 0.67m) was more marked in the ioxaglate group than in the other treatment groups (p = 0.0001) during right coronary angiography. The same characteristics, but less marked, were observed during left coronary angiography, the ioxaglate group (mean 0.251mm) differing from the iopamidol group (mean 0.050mm) (p = 0.04). No significant difference in severe adverse reactions were detected between these groups (ioxaglate 1, iopamidol 1). Ioxaglate produced mild side effects (nausea, vomitus, urticaria) in 16% of the patients, the other two contrast agents producing side effects in 1%.

  6. 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. ...

  7. Catheter Angiography

    Medline Plus

    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. ...

  8. Comparative Study on 16-slice CT Coronary Angiography vs Conventional Coronary Angiography-A Report of 38 Cases

    Institute of Scientific and Technical Information of China (English)

    Yan CHEN; Ping HAN; Bo LIANG; Huimin LIANG; Ziqiao LEI; Zhiliang TIAN; Gansheng FENG; Jie XIAO

    2008-01-01

    The clinical application of 16-slice CT coronary angiography (CTCA) and the impact of plaques differently characterized on assessing coronary artery stenosis were evaluated. Thirty-eight patients with coronary artery disease diagnosed by conventional coronary angiography (CAG) un- derwent 16-slice CTCA (collimation: 16×0.75 mm; rotation time: 420 msec; kernel: 35f; effective current: 500 mAs; tube voltage: 120 kV). The interval between CTCA and CAG was within one month. CTCA was evaluated by consensus of two independent experienced radiologists unknowing CAG findings. Original images, maximum intensity projections and multiplanar reconstructions were used to assess coronary artery stenosis. For a determined plaque an attenuation value≥130 HU was considered as calcified, and <130 HU noncalcified. The plaques were then classified into significant calcification (extensive calcification), medium calcification (small isolated calcification) and noncal- cification. The diagnostic accuracy of 16-slice CTCA findings as well as to detect ≥50% stenoses caused by plaques was evaluated respectively regarding CAG as the standard of reference. In com- parison with CAG findings, the sensitivity, specificity, positive and negative predictive value derived from CTCA for mild stenosis (<50%) were 72.7%, 38.5%, 50%, 62.5%, respectively; for moderate stenosis (50%-75%) 82.4%, 72.7%, 70%, 84.2%, resepctively; and for severe coronary stenosis (>75%) 85%, 90.5%, 81%, 92.7% respectively. With the increase of stenoses degree, the value of CTCA was greater. For the classification of the plaque calcification with ≥50% stenosis CTCA at- tained the sensitivity, specificity, positive and negative predictive value for severe calcificatoin 73.3%, 22.2%, 61.1% and 33.3%, respectively; for moderate calcification 70%, 55.6%, 63.6% and 62.5%, respectively; for noncalcification 93.8%, 85.7%, 93.8% and 85.7% respectively. CTCA was restricted in assessing coronary artery stenosis in the

  9. Retrospective analysis of the prevalence of asymptomatic cerebral aneurysm in 4518 patients undergoing magnetic resonance angiography. When does cerebral aneurysm develop?

    Energy Technology Data Exchange (ETDEWEB)

    Horikoshi, Toru; Yamagata, Zentaro; Nukui, Hideaki [Yamanashi Medical Univ., Tamaho (Japan); Akiyama, Iwao [Akiyama Neurosurgical Clinic, Nirasaki, Yamanashi (Japan)

    2002-03-01

    The natural history of cerebral aneurysms was investigated by measuring the prevalence of incidentally found unruptured aneurysms in the general population and evaluating the characteristics including risk factors. 'De novo' formation of aneurysm was also demographically estimated. The prevalence of incidental aneurysm was evaluated among 4518 patients who underwent magnetic resonance (MR) angiography for various reasons in a neurosurgical institute. Double the number of patients were randomly selected from the remaining patients without aneurysm as the Control group so that sex and age group were matched to the Aneurysm group. One hundred twenty seven patients (2.8%) had diagnoses of aneurysm. The prevalence of asymptomatic aneurysm among middle-aged and elderly patients were predominant in women and increased with age in both sexes. Patients with aneurysms had significantly more hypertension and family history of subarachnoid hemorrhage compared to the controls. The prevalence was markedly increased in the 8th decade in men and the 7th decade in women, and new aneurysms seemed to develop predominantly around these decades. Cerebral aneurysms become detectable on MR angiography in the middle or later decades, and women tend to develop aneurysm earlier than men. Hypertension and family history of subarachnoid hemorrhage are probably risk factors for the development of aneurysm. (author)

  10. Efficacy of Three-Dimensional Contrast-Enhanced Magnetic Resonance Angiography (3D CE-MRA in the Diagnosis of Thoracic Outlet Syndrome

    Directory of Open Access Journals (Sweden)

    Ercüment Ünlü

    2011-09-01

    Full Text Available Objective: The purpose of this study is to evaluate the effect of various upper extremity positions (adduction-abduction on vascular structures in contrast-enhanced three-dimensional MR angiographic studies performed in patients with thoracic outlet syndrome.Materials and Methods: Twenty-two consecutive patients with clinical symptoms of neurovascular thoracic outlet syndrome were examined by 1.0 T MR unit. Examinations were studied by three-dimensional contrast-enhanced MR angiography with the arms positioned in abduction and adduction in the same patients. Results: In twenty-one of 44 subclavian arteries, impingement or stenosis with different degrees were found. Majority of lesions were localized in the costoclavicular region. Venous phase sequences of contrast-enhanced MR angiography showed compression of the subclavian vein in the 17 areas.Conclusion: Thoracic outlet syndrome remains controversial in both diagnosis and treatment, particulary in patients with no muscle atrophy, hand ischemia findings or venous stasis symptoms. Three-dimensional contrast-enhanced MR angiography is noninvasive and requires neither ionizing radiation nor administration of iodinated contrast material- and may be used to diagnose early compression findings and stenosis of the subclavian vessels.

  11. Noncontrast-enhanced magnetic resonance renal angiography using a repetitive artery and venous labelling technique at 3 T: comparison with contrast-enhanced magnetic resonance angiography in subjects with normal renal function

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Yoon [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Samsung Medical Center, Seoul (Korea, Republic of); Severance Hospital, Yonsei University College of Medicine, Department of Radiology and Research Institute of Radiological Science, Seoul (Korea, Republic of); Kim, Chan Kyo; Park, Byung Kwan [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Samsung Medical Center, Seoul (Korea, Republic of); Kim, EunJu [Philips Healthcare Korea, Seoul (Korea, Republic of)

    2014-09-13

    To investigate the feasibility of noncontrast-enhanced MR angiography (NC-MRA) using the repetitive artery and venous labelling (RAVEL) technique to evaluate renal arteries compared to contrast-enhanced MR angiography (CE-MRA). Twenty-five subjects with normal renal function underwent NC-MRA using a RAVEL technique and CE-MRA at 3 T. Two independent readers analysed the MRA images. Image quality, number of renal arteries, presence or absence of an early branching vessel, and diameter of the main renal arteries were evaluated. The overall image quality of NC-MRA was fair or greater in 88 % of right and 92 % of left renal arteries, while it was 96 % in both sides with CE-MRA. On NC-MRA, the number of renal arteries in all subjects was perfectly predicted by both readers. Sensitivity and specificity for predicting early branching vessels were 82 % and 100 % for reader 1 and 82 % and 95 % for reader 2. Inter-modality agreement for comparing the diameters of main renal arteries was good or excellent at all segments for both readers. Inter-reader agreement was moderate or good at all segments except at the right distal segment on NC-MRA. NC-MRA with the RAVEL technique at 3 T may have comparable diagnostic feasibility for evaluating renal arteries compared to CE-MRA. (orig.)

  12. Computed tomography angiography and magnetic resonance imaging performance of acute segmental single compartment syndrome following an Achilles tendon repair: A case report and literature review

    Institute of Scientific and Technical Information of China (English)

    Li-Feng Jiang; Hang Li; Zeng-Feng Xin; Li-Dong Wu

    2016-01-01

    Acute compartment syndrome of the lower extremity is a serious postinjury complication that requires emergency treatment.Early diagnosis is of paramount importance for a good outcome.Four muscle compartments in the calf (anterior,lateral,deep posterior,and superficial posterior) may be individually or collectively affected.Acute segmental single-compartment syndrome is an extremely rare condition characterized by high pressure in a single compartment space with threatening of the segmental tissue viability.In this case report,we describe a young man with Achilles tendon rupture who complained of postoperative pain in the anterior tibial region.Emergent computed tomography angiography and magnetic resonance imaging revealed local muscle edema.Segmental anterior compartment syndrome was diagnosed and fasciotomy was performed.

  13. Non-contrast-enhanced 4D MR angiography with STAR spin labeling and variable flip angle sampling: a feasibility study for the assessment of Dural Arteriovenous Fistula.

    Science.gov (United States)

    Jang, Jinhee; Schmitt, Peter; Kim, Bom-yi; Choi, Hyun Seok; Jung, So-Lyung; Ahn, Kook-Jin; Kim, Inseong; Paek, Munyoung; Kim, Bum-soo

    2014-04-01

    This study aimed to evaluate the feasibility of non-contrast-enhanced 4D magnetic resonance angiography (NCE 4D MRA) with signal targeting with alternative radiofrequency (STAR) spin labeling and variable flip angle (VFA) sampling in the assessment of dural arteriovenous fistula (DAVF) in the transverse sinus. Nine patients underwent NCE 4D MRA for the evaluation of DAVF in the transverse sinus at 3 T. One patient was examined twice, once before and once after the interventional treatment. All patients also underwent digital subtraction angiography (DSA) and/or contrast-enhanced magnetic resonance angiography (CEMRA). For the acquisition of NCE 4D MRA, a STAR spin tagging method was used, and a VFA sampling was applied in the data readout module instead of a constant flip angle. Two readers evaluated the NCE 4D MRA data for the diagnosis of DAVF and its type with consensus. The results were compared with those from DSA and/or CEMRA. All patients underwent NCE 4D MRA without any difficulty. Among seven patients with patent DAVFs, all cases showed an early visualization of the transverse sinus on NCE 4D MRA. Except for one case, the type of DAVF of NCE 4D MRA was agreed with that of reference standard study. Cortical venous reflux (CVR) was demonstrated in two cases out of three patients with CVR. NCE 4D MRA with STAR tagging and VFA sampling is technically and clinically feasible and represents a promising technique for assessment of DAVF in the transverse sinus. Further technical developments should aim at improvements of spatial and temporal coverage.

  14. Non-contrast-enhanced 4D MR angiography with STAR spin labeling and variable flip angle sampling: a feasibility study for the assessment of Dural Arteriovenous Fistula

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jinhee; Kim, Bom-yi; Choi, Hyun Seok; Jung, So-Lyung; Ahn, Kook-Jin; Kim, Bum-soo [The Catholic University of Korea, Department of Radiology, Seoul St. Mary' s Hospital, College of Medicine, Seoul (Korea, Republic of); Schmitt, Peter [Siemens AG, Healthcare Sector, Erlangen (Germany); Kim, Inseong; Paek, Munyoung [Siemens AG, Healthcare, Seoul (Korea, Republic of)

    2014-04-15

    This study aimed to evaluate the feasibility of non-contrast-enhanced 4D magnetic resonance angiography (NCE 4D MRA) with signal targeting with alternative radiofrequency (STAR) spin labeling and variable flip angle (VFA) sampling in the assessment of dural arteriovenous fistula (DAVF) in the transverse sinus. Nine patients underwent NCE 4D MRA for the evaluation of DAVF in the transverse sinus at 3 T. One patient was examined twice, once before and once after the interventional treatment. All patients also underwent digital subtraction angiography (DSA) and/or contrast-enhanced magnetic resonance angiography (CEMRA). For the acquisition of NCE 4D MRA, a STAR spin tagging method was used, and a VFA sampling was applied in the data readout module instead of a constant flip angle. Two readers evaluated the NCE 4D MRA data for the diagnosis of DAVF and its type with consensus. The results were compared with those from DSA and/or CEMRA. All patients underwent NCE 4D MRA without any difficulty. Among seven patients with patent DAVFs, all cases showed an early visualization of the transverse sinus on NCE 4D MRA. Except for one case, the type of DAVF of NCE 4D MRA was agreed with that of reference standard study. Cortical venous reflux (CVR) was demonstrated in two cases out of three patients with CVR. NCE 4D MRA with STAR tagging and VFA sampling is technically and clinically feasible and represents a promising technique for assessment of DAVF in the transverse sinus. Further technical developments should aim at improvements of spatial and temporal coverage. (orig.)

  15. Melatonin mitigate cerebral vasospasm after experimental subarachnoid hemorrhage: a study of synchrotron radiation angiography

    Science.gov (United States)

    Cai, J.; He, C.; Chen, L.; Han, T.; Huang, S.; Huang, Y.; Bai, Y.; Bao, Y.; Zhang, H.; Ling, F.

    2013-06-01

    Cerebral vasospasm (CV) after subarachnoid hemorrhage (SAH) is a devastating and unsolved clinical issue. In this study, the rat models, which had been induced SAH by prechiasmatic cistern injection, were treated with melatonin. Synchrotron radiation angiography (SRA) was employed to detect and evaluate CV of animal models. Neurological scoring and histological examinations were used to assess the neurological deficits and CV as well. Using SRA techniques and histological analyses, the anterior cerebral artery diameters of SAH rats with melatonin administration were larger than those without melatonin treatment (p melatonin were less than those without melatonin treatment (p melatonin could mitigate CV after experimental SAH.

  16. Efficiency of ultrasonography and CT angiography in follow-up studies of carotid stent and percutaneous transluminal angioplasty

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Chang Woo; Lee, Byung Hee; Chung, Bong Sub; Ahn, Jung Yong; Heo, Kyung; Kho, Young Sik [Pundang CHA General Hospital, Pochon CHA Univ. College of Medicine, Pochon (Korea, Republic of)

    1999-12-01

    The aim of this study was to determine a more appropriate method for follow-up of carotid stenting by comparing the efficiency of US and CT angiography. Eleven carotid arteries of seven patients(men:5, women:2, mean age:56.4years) who underwent stent placement and percutaneous transluminal angioplasty(PTA) because of carotid stenosis were studied. The follow-up periods ranged from three to eleven (mean, five) months, and US and CT angiography were performed in one day. Color duplex sonography was performed with a 10 MHz linear array transducer. After spiral CT scan were obtained, MPR images were reconstructed on a workstation. Retrospective imaging analysis specifically focused on [1] stent configuration, [2] the accuracy of internal diameter measurement, [3] the detection of blood flow and the measurement of blood flow velocity, [4] the presence of atheroma and intraluminal thrombi, [5] the measurement of stent location, and [6] artifacts. US was more accurate than CT angiography for measuring internal diameter. In all cases, US and CT angiography were able to detect the blood flow at carotid artery, and utilizing the Doppler spectrum, flow velocity was measured. US showed atheromas in all cases but CT angiography demonstrated calcified atheromas in three cases only. In six cases, US failed to determine stent location, though in this respect CT angiography was successful in all cases. Artifacts of US were small reverberation artifact(11/11) of the stent and a defective color Doppler signal caused by acoustic shadowing of atheroma calcification(3/11). Artifacts of CT angiogrpahy were hardbeam artifact of the stent(11/11) and motion artifact(3/11). US was superior to CT angiography in accuracy of measuring stent diameter, hemodynamic assessment, high-resolution views of the luminal state of the stent and minimal artifacts for the non-invasive follow-up studies of carotid stenting.

  17. Cost evaluation of cardiovascular magnetic resonance versus coronary angiography for the diagnostic work-up of coronary artery disease: Application of the European Cardiovascular Magnetic Resonance registry data to the German, United Kingdom, Swiss, and United States health care systems

    Directory of Open Access Journals (Sweden)

    Moschetti Karine

    2012-06-01

    Full Text Available Abstract Background Cardiovascular magnetic resonance (CMR has favorable characteristics for diagnostic evaluation and risk stratification of patients with known or suspected CAD. CMR utilization in CAD detection is growing fast. However, data on its cost-effectiveness are scarce. The goal of this study is to compare the costs of two strategies for detection of significant coronary artery stenoses in patients with suspected coronary artery disease (CAD: 1 Performing CMR first to assess myocardial ischemia and/or infarct scar before referring positive patients (defined as presence of ischemia and/or infarct scar to coronary angiography (CXA versus 2 a hypothetical CXA performed in all patients as a single test to detect CAD. Methods A subgroup of the European CMR pilot registry was used including 2,717 consecutive patients who underwent stress-CMR. From these patients, 21% were positive for CAD (ischemia and/or infarct scar, 73% negative, and 6% uncertain and underwent additional testing. The diagnostic costs were evaluated using invoicing costs of each test performed. Costs analysis was performed from a health care payer perspective in German, United Kingdom, Swiss, and United States health care settings. Results In the public sectors of the German, United Kingdom, and Swiss health care systems, cost savings from the CMR-driven strategy were 50%, 25% and 23%, respectively, versus outpatient CXA. If CXA was carried out as an inpatient procedure, cost savings were 46%, 50% and 48%, respectively. In the United States context, cost savings were 51% when compared with inpatient CXA, but higher for CMR by 8% versus outpatient CXA. Conclusion This analysis suggests that from an economic perspective, the use of CMR should be encouraged as a management option for patients with suspected CAD.

  18. Catheter Angiography

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    Full Text Available ... you! 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 ...

  19. 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 ...

  20. Catheter Angiography

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

  1. Catheter Angiography

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    Full Text Available ... medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ... accredited facilities database . This website does not provide cost information. The costs for specific medical imaging tests, ...

  2. 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 ( ...

  3. Catheter Angiography

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

  4. Catheter Angiography

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    Full Text Available ... X-rays are a form of radiation like light or radio waves. X-rays pass through most ... catheter angiography to lessen the risk of allergic reaction. Another option is to undergo a different exam ...

  5. Catheter Angiography

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    Full Text Available ... top of page What are the benefits vs. risks? Benefits Angiography may eliminate the need for surgery. ... in the typical diagnostic range for this exam. Risks There is always a slight chance of cancer ...

  6. 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 ...

  7. 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 ... these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | Site Map Copyright © 2017 Radiological ...

  8. Catheter Angiography

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    Full Text Available ... few millimeters) in the skin where the catheter can be inserted into an artery. The catheter is ... need for surgery. If surgery remains necessary, it can be performed more accurately. Catheter angiography presents a ...

  9. Catheter Angiography

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    Full Text Available ... most cases, the kidneys will regain their normal function within five to seven days. Rarely, the catheter ... limitations of Catheter Angiography? Patients with impaired kidney function, especially those who also have diabetes, are not ...

  10. 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 ...

  11. A STUDY TO COMPARE FUNDUS FLUORESCEIN ANGIOGRAPHY AND OPTICAL COHERENCE TOMOGRAPHY IN AGE RELATED MACULAR DEGENERATION

    Directory of Open Access Journals (Sweden)

    Rani Sujatha

    2016-02-01

    Full Text Available PURPOSE To compare the diagnostic accuracy of optical coherence tomography with Fundus Fluorescein Angiography in diagnosing Age related macular degeneration. METHODS A total 25 patients newly diagnosed as Age related macular degeneration were included in the study. The study was done during the time period between August 2013 to November 2015 this is a prospective randomized hospital based study. RESULTS Maximum no of patients affected belonged to the age group of 50-70 years and 60% were females. The most common symptom was defective vision accounting for 92%. Hypertension and hyperlipidemia were the most common risk factors. 12% of the cases had unilateral disease and 88% had bilateral disease. 6% of eyes were normal in both FFA and OCT. 62% of the eyes by FFA and 61% of the eyes by OCT had dry ARMD and 32 % of the eye by FFA and 33 % by OCT had wet ARMD. CONCLUSION Fundus Fluorescein Angiography is the gold standard tool for screening ARMD and OCT is more specific in detecting early subretinal neovascular membrane and also to assess the activity of the neovascular membranes. Hence OCT is superior to FFA in diagnosing early wet ARMD and thus helps in early management of patients with ARMD.

  12. The frequency of intracranial arterial fenestrations: A study with 64-detector CT-angiography

    Energy Technology Data Exchange (ETDEWEB)

    Bayrak, Aylin Hasanefendioglu, E-mail: aylin_has@yahoo.com [Dicle University, School of Medicine, Radiology Department, Diyarbakir (Turkey); Senturk, Senem, E-mail: ssenturk@dicle.edu.tr [Dicle University, School of Medicine, Radiology Department, Diyarbakir (Turkey); Akay, Hatice Ozturkmen, E-mail: hozturkmen@gmail.com [Veni Vidi Hospital, Diyarbakir (Turkey); Ozmen, Cihan Akgul, E-mail: cihanakgul@dicle.edu.tr [Dicle University, School of Medicine, Radiology Department, Diyarbakir (Turkey); Bukte, Yasar, E-mail: ybukte@dicle.edu.tr [Dicle University, School of Medicine, Radiology Department, Diyarbakir (Turkey); Nazaroglu, Hasan, E-mail: hnazarog@dicle.edu.tr [Dicle University, School of Medicine, Radiology Department, Diyarbakir (Turkey)

    2011-03-15

    Fenestration is a vascular variation that begins with a common origin, then splits into two parallel luminal channels and rejoins distally. Potential association between anomalies of cerebral circulation and increased occurrence of aneurysm makes intracranial arterial fenestrations important. The planning of intracranial arterial interventions may be complicated if a fenestration occurs proximal to the site of intended treatment. This study is planned to determine the frequency of fenestrations on CT angiography and to search whether there is relationship between aneurysms and fenestrations. CT angiographies of 395 consecutive patients, performed by 64-detector CT, were retrospectively reviewed for aneurysms and fenestrations. Overall fenestration frequency, fenestration frequency in patients with and without aneurysm, and aneurysm frequency in patients with and without fenestration were searched. Demographic characteristics of patients were also compared. Overall fenestration frequency was 12.9%. Vertebrobasilar system (5.56%) and anterior communicating region (5.32%) were the two most frequent sites of fenestration. The rate of fenestrations was not significantly different between patients who had and did not have aneurysms. Mean age was significantly higher, and females were predominant in patients with aneurysms. However our results did not show significant difference in age and sex of patients with fenestrations. The frequency of fenestrations in this study is higher than in previously published radiological studies, suggesting that fenestrations are relatively common. There is no significant relationship between the frequency of aneurysms and fenestrations.

  13. Intraindividual quantitative and qualitative comparison of gadopentetate dimeglumine and gadobutrol in time-resolved contrast-enhanced 4-dimensional magnetic resonance angiography in minipigs.

    Science.gov (United States)

    Hadizadeh, Dariusch Reza; Jost, Gregor; Pietsch, Hubertus; Weibrecht, Martin; Perkuhn, Michael; Boschewitz, Jack Maria; Keil, Vera Catharina; Träber, Frank; Kukuk, Guido Matthias; Schild, Hans Heinz; Willinek, Winfried Albert

    2014-07-01

    The concentration and relaxivities of contrast agents affect quantitative and qualitative image quality in contrast-enhanced time-resolved 4-dimensional magnetic resonance angiography (4D-MRA). Gadobutrol has a high relaxivity and is the only gadolinium (Gd)-based contrast agent approved for clinical use at a 1 M concentration. This promises to confer superior bolus characteristics by generating a steeper and shorter bolus with a higher peak Gd concentration. The purpose of this study was to quantitatively examine bolus characteristics of 1 M gadobutrol compared with 0.5 M gadopentetate dimeglumine and to evaluate image quality in thoracoabdominal 4D-MRA. A total of 7 Goettingen minipigs received dynamic computed tomography (CT) on a clinical 64-slice CT (transverse slices, 80 kV, 20 seconds, 0.3 s/dynamic frame) and 4D-MRA (time-resolved imaging with stochastic trajectories; 1. transverse slices, 30 seconds, 0.49 s/frame; 2. coronal slices, 70 seconds, 1.3 s/frame) on a 1.5-T clinical whole-body magnetic resonance imaging under general anesthesia using gadopentetate dimeglumine and gadobutrol in an intraindividual comparative study. Computed tomography attenuations were converted into Gd concentrations on the basis of previous phantom experiments. Quantitative analysis included measurements of the full width at half maximum, time-to-peak intervals, and peak of each bolus in dynamic CT and transverse 4D-MRA. These studies were carried out at equivalent contrast agent flow rates of 1 mL/s. Quantitative analysis (7 arteries and veins) and qualitative image analysis were performed on coronal thoracoabdominal 4D-MRA studies carried out at flow rates of 1 mL/s and, in the case of gadopentetate dimeglumine, also at molarity-adjusted flow rates of 2 mL/s. The bolus in both transverse 4D-MRA and dynamic CT was significantly narrower (full width at half maximum), earlier (time to peak), and higher (signal intensity enhancement in 4D-MRA, Gd concentration in dynamic CT) when

  14. Polygamy and Risk of Coronary Artery Disease in Men Undergoing Angiography: An Observational Study

    Science.gov (United States)

    Lotfi, Amir; Al-Murayeh, Mushabab; Al-kaabi, Salem; Al-Faifi, Salem M.; Alama, Mohamed N.; Hersi, Ahmad S.; Dixon, Ciaran M.; Ahmed, Waleed; Al-Shehri, Mohamed; Youssef, Ali; Elimam, Ahmed Moustafa; Abougalambou, Ayman S.; Murad, Waheed; Alsheikh-Ali, Alawi A.

    2017-01-01

    Epidemiologic evidence suggests a link between psychosocial risk factors such as marital status and coronary artery disease (CAD). Polygamy (multiple concurrent wives) is a distinct marital status practiced in many countries in Asia and the Middle East, but its association with CAD is not well defined. We conducted a multicenter, observational study of consecutive patients undergoing coronary angiography during the period from April 1, 2013, to March 30, 2014. Of 1,068 enrolled patients, 687 were married men. Polygamy was reported in 32% of married men (1 wife: 68%, 2 wives: 19%, 3 wives: 10%, and 4 wives: 3%). When stratified by number of wives, significant baseline differences were observed in age, type of community (rural versus urban), prior coronary artery bypass grafting (CABG), and household income. After adjusting for baseline differences, there was a significant association between polygamy and CAD (adjusted OR 4.6 [95% CI 2.5, 8.3]), multivessel disease (MVD) (adjusted OR 2.6 [95% CI 1.8, 3.7]), and left main disease (LMD) (adjusted OR 3.5 [95% CI 2.1, 5.9]). Findings were consistent when the number of wives was analyzed as a continuous variable. In conclusion, among married men undergoing coronary angiography for clinical indications, polygamy is associated with the presence of significant CAD, MVD, and LMD. PMID:28250991

  15. Polygamy and Risk of Coronary Artery Disease in Men Undergoing Angiography: An Observational Study

    Directory of Open Access Journals (Sweden)

    Amin Daoulah

    2017-01-01

    Full Text Available Epidemiologic evidence suggests a link between psychosocial risk factors such as marital status and coronary artery disease (CAD. Polygamy (multiple concurrent wives is a distinct marital status practiced in many countries in Asia and the Middle East, but its association with CAD is not well defined. We conducted a multicenter, observational study of consecutive patients undergoing coronary angiography during the period from April 1, 2013, to March 30, 2014. Of 1,068 enrolled patients, 687 were married men. Polygamy was reported in 32% of married men (1 wife: 68%, 2 wives: 19%, 3 wives: 10%, and 4 wives: 3%. When stratified by number of wives, significant baseline differences were observed in age, type of community (rural versus urban, prior coronary artery bypass grafting (CABG, and household income. After adjusting for baseline differences, there was a significant association between polygamy and CAD (adjusted OR 4.6 [95% CI 2.5, 8.3], multivessel disease (MVD (adjusted OR 2.6 [95% CI 1.8, 3.7], and left main disease (LMD (adjusted OR 3.5 [95% CI 2.1, 5.9]. Findings were consistent when the number of wives was analyzed as a continuous variable. In conclusion, among married men undergoing coronary angiography for clinical indications, polygamy is associated with the presence of significant CAD, MVD, and LMD.

  16. Duplex ultrasound and computed tomography angiography in the follow-up of endovascular abdominal aortic aneurysm repair: a comparative study*

    Science.gov (United States)

    Cantador, Alex Aparecido; Siqueira, Daniel Emílio Dalledone; Jacobsen, Octavio Barcellos; Baracat, Jamal; Pereira, Ines Minniti Rodrigues; Menezes, Fábio Hüsemann; Guillaumon, Ana Terezinha

    2016-01-01

    Objective To compare duplex ultrasound and computed tomography (CT) angiography in terms of their performance in detecting endoleaks, as well as in determining the diameter of the aneurysm sac, in the postoperative follow-up of endovascular abdominal aortic aneurysm repair. Materials and Methods This was a prospective study involving 30 patients who had undergone endovascular repair of infrarenal aortoiliac aneurysms. Duplex ultrasound and CT angiography were performed simultaneously by independent radiologists. Measurements of the aneurysm sac diameter were assessed, and the presence or absence of endoleaks was determined. Results The average diameter of the aneurysm sac, as determined by duplex ultrasound and CT angiography was 6.09 ± 1.95 and 6.27 ± 2.16 cm, respectively. Pearson's correlation coefficient showing a statistically significant correlation (R = 0.88; p < 0.01). Comparing the duplex ultrasound and CT angiography results regarding the detection of endoleaks, we found that the former had a negative predictive value of 92.59% and a specificity of 96.15%. Conclusion Our results show that there is little variation between the two methods evaluated, and that the choice between the two would have no significant effect on clinical management. Duplex ultrasound could replace CT angiography in the postoperative follow-up of endovascular aneurysm repair of the infrarenal aorta, because it is a low-cost procedure without the potential clinical complications related to the use of iodinated contrast and exposure to radiation. PMID:27777476

  17. Duplex ultrasound and computed tomography angiography in the follow-up of endovascular abdominal aortic aneurysm repair: a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Cantador, Alex Aparecido; Siqueira, Daniel Emilio Dalledone; Jacobsen, Octavio Barcellos; Baracat, Jamal; Pereira, Ines Minniti Rodrigues; Menezes, Fabio Hüsemann; Guillaumon, Ana Terezinha, E-mail: alex_cantador@yahoo.com.br [Universidade Estadual de Campinas (FCM/UNICAMP), Campinas, SP (Brazil). Faculdade de Ciencias Medicas

    2016-07-15

    Objective: To compare duplex ultrasound and computed tomography (CT) angiography in terms of their performance in detecting endoleaks, as well as in determining the diameter of the aneurysm sac, in the postoperative follow-up of endovascular abdominal aortic aneurysm repair. Materials and Methods: This was a prospective study involving 30 patients who had undergone endovascular repair of infrarenal aortoiliac aneurysms. Duplex ultrasound and CT angiography were performed simultaneously by independent radiologists. Measurements of the aneurysm sac diameter were assessed, and the presence or absence of endoleaks was determined. Results: The average diameter of the aneurysm sac, as determined by duplex ultrasound and CT angiography was 6.09 ± 1.95 and 6.27 ± 2.16 cm, respectively. Pearson's correlation coefficient showing a statistically significant correlation (R = 0.88; p < 0.01). Comparing the duplex ultrasound and CT angiography results regarding the detection of endoleaks, we found that the former had a negative predictive value of 92.59% and a specificity of 96.15%. Conclusion: Our results show that there is little variation between the two methods evaluated, and that the choice between the two would have no significant effect on clinical management. Duplex ultrasound could replace CT angiography in the postoperative follow-up of endovascular aneurysm repair of the infrarenal aorta, because it is a low-cost procedure without the potential clinical complications related to the use of iodinated contrast and exposure to radiation. (author)

  18. Duplex ultrasound and computed tomography angiography in the follow-up of endovascular abdominal aortic aneurysm repair: a comparative study

    Directory of Open Access Journals (Sweden)

    Alex Aparecido Cantador

    Full Text Available Abstract Objective: To compare duplex ultrasound and computed tomography (CT angiography in terms of their performance in detecting endoleaks, as well as in determining the diameter of the aneurysm sac, in the postoperative follow-up of endovascular abdominal aortic aneurysm repair. Materials and Methods: This was a prospective study involving 30 patients who had undergone endovascular repair of infrarenal aortoiliac aneurysms. Duplex ultrasound and CT angiography were performed simultaneously by independent radiologists. Measurements of the aneurysm sac diameter were assessed, and the presence or absence of endoleaks was determined. Results: The average diameter of the aneurysm sac, as determined by duplex ultrasound and CT angiography was 6.09 ± 1.95 and 6.27 ± 2.16 cm, respectively. Pearson's correlation coefficient showing a statistically significant correlation (R = 0.88; p < 0.01. Comparing the duplex ultrasound and CT angiography results regarding the detection of endoleaks, we found that the former had a negative predictive value of 92.59% and a specificity of 96.15%. Conclusion: Our results show that there is little variation between the two methods evaluated, and that the choice between the two would have no significant effect on clinical management. Duplex ultrasound could replace CT angiography in the postoperative follow-up of endovascular aneurysm repair of the infrarenal aorta, because it is a low-cost procedure without the potential clinical complications related to the use of iodinated contrast and exposure to radiation.

  19. High-resolution steady state magnetic resonance angiography of the carotid arteries: are intravascular agents necessary?: feasibility and preliminary experience with gadobenate dimeglumine.

    Science.gov (United States)

    Anzidei, Michele; Napoli, Alessandro; Marincola, Beatrice Cavallo; Kirchin, Miles A; Neira, Cristina; Geiger, Daniel; Zaccagna, Fulvio; Catalano, Carlo; Passariello, Roberto

    2009-12-01

    To prospectively evaluate the potential of gadobenate dimeglumine for high-resolution steady-state (SS) contrast-enhanced magnetic resonance angiography (CE-MRA) of the carotid arteries as an adjunct to conventional first-pass (FP) MRA, with computed tomography angiography (CTA) and digital subtraction angiography (DSA) as reference. Institutional ethics committee approval and written informed consent were obtained. Forty consecutive patients underwent conventional FP MRA with 15 mL gadobenate dimeglumine, using a conventional 3D FLASH sequence (14 sec acquisition time). Immediately afterward, SS images were obtained using a high resolution coronal 3D FLASH sequence (240 sec acquisition time). All patients also underwent CTA and conventional DSA within 8 +/- 3 days. Three experienced radiologists assessed FP and SS image quality and calculated sensitivity, specificity, accuracy, and predictive values for stenosis grade and length, plaque morphology, and tandem lesions using DSA as reference. Detected stenoses were quantified and compared (Spearman rank correlation coefficient, [R(s)]; McNemar test) with DSA and CTA findings. Inter-read variability was assessed using kappa (kappa) statistics. The impact of SS acquisitions on diagnostic confidence and patient management was assessed. MRA FP and SS image quality was excellent in 63 (78.8%) and 46 (57.5%) vessels, adequate in 11 (13.8%) and 20 (25.0%) vessels, and poor in 6 (7.5%) and 14 (17.5%) vessels, respectively. Area under the curve analysis revealed no significant differences between MRA FP, MRA FP + SS, and CTA for the grading of stenoses (P = 0.838; accuracy values of 97.4%, 97.4%, and 98.7%, respectively). Greater accuracy (P < 0.001) was noted for FP + SS images over FP images alone for the assessment of plaque morphology (96.1% for FP + SS images vs. 83.3% for FP). Increased diagnostic confidence was noted for 49 (61.3%) vessels because of additional SS images whereas an impact on final diagnosis was noted

  20. Time-of-flight magnetic resonance angiography for follow-up of coil embolization with enterprise stent intracranial aneurysm: Usefulness of source images

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Dae; Kim, Kang Min; Lee, Woong Jae; Sohn, Chul Ho; Kang, Hyun Seung; Kim, Jeong Eun; Han, Moon Hee [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2014-02-15

    The aim of this study was to determine the interobserver and intermodality agreement in the interpretation of time-of-flight (TOF) MR angiography (MRA) for the follow-up of coiled intracranial aneurysms with the Enterprise stent. Two experienced neurointerventionists independently reviewed the follow-up MRA studies of 40 consecutive patients with 44 coiled aneurysms. All aneurysms were treated with assistance from the Enterprise stent and the radiologic follow-up intervals were greater than 6 months after the endovascular therapy. Digital subtraction angiography (DSA) served as the reference standard. The degree of aneurysm occlusion was determined by an evaluation of the maximal intensity projection (MIP) and source images (SI) of the TOF MRA. The capability of the TOF MRA to depict the residual flow within the coiled aneurysms and the stented parent arteries was compared with that of the DSA. DSA showed stable occlusions in 25 aneurysms, minor recanalization in 8, and major recanalization in 11. Comparisons between the TOF MRA and conventional angiography showed that the MIP plus SI had almost perfect agreement (κ = 0.892, range 0.767 to 1.000) and had better agreement than with the MIP images only ((κ = 0.598, range 0.370 to 0.826). In-stent stenosis of more than 33% was observed in 5 cases. Both MIP and SI of the MRA showed poor depiction of in-stent stenosis compared with the DSA. TOF MRA seemed to be reliable in screening for aneurysm recurrence after coil embolization with Enterprise stent assistance, especially in the evaluation of the SI, in addition to MIP images in the TOF MRA.

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

    Science.gov (United States)

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

    2012-10-01

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

  2. Lack of Serum Creatinine Decrease After Coronary Angiography Despite Prophylactic Hydration After Routine Coronary Angiography/Angioplasty in Stable Angina Patients - Pilot Study

    Directory of Open Access Journals (Sweden)

    Pawel Burchardt

    2016-03-01

    Full Text Available Background/Aims: To prevent contrast induced renal dysfunction a periprocedural prophylactic hydration is applied. Due to dilution it should cause a drop in serum creatinine concentration (SCR. Surprisingly, no reduction in SCR after contrast admission is found in up to 25% of patients as early as 12-18 hours after coronary angiography/angioplasty. This study aims to find a clinical explanation as well as predict circumstances for this phenomenon. Methods: Retrospective clinical and laboratory data was used from 341 patients who underwent elective coronary angiography/angioplasty, received a prophylactic hydration, and had serum creatinine concentration measured prior to, and 12-18 hours after invasive procedure with iodine contrast administration. To exclude an improper hydration due to no creatinine decrease, the number of red blood cells was analysed as well as hemoglobin and hematocrit in blood donations collected during the study time points. Results: The resulting lack of serum creatinine reduction could be explained by dehydration (measured by increase in number of RBC, HGB and HCT only in 13.5% , 10.8 %, and 20% of cases, respectively. Any form of abnormal glucose metabolism combined with either baseline serum creatinine concentration 86.77 mL/min, or GFR by CKD EPI >80.08 mL/min/1.73 m2, or GFR by MDRD >74.48 mL/min/1.73 m2 were the predictors for no creatinine decrease at outcome. Additionally, it was demonstrated that the lack of creatinine decrease was more often observed among those patients whose initial renal function was better than in the subjects with reduction of SCR. Conclusions: This observation requires further prospective investigation on extended group of patients.

  3. MR angiography

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-01-01

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

  4. Improving the image quality of contrast-enhanced MR angiography by automated image registration: A prospective study in peripheral arterial disease of the lower extremities

    Energy Technology Data Exchange (ETDEWEB)

    Menke, Jan, E-mail: Menke-J@T-Online.d [Department of Diagnostic Radiology, University Hospital, Robert-Koch-Strasse 40, 37075 Goettingen (Germany)

    2010-09-15

    Objective: If a patient has moved during digital subtraction angiography (DSA), manual pixel shift can improve the image quality. This study investigated whether such image registration can also improve the quality of contrast-enhanced magnetic resonance angiography (MRA) in patients with peripheral arterial disease of the lower extremities. Materials and methods: 404 leg MRAs of patients likely to have peripheral artery disease were included in this prospective study. The standard non-registered MRAs were compared to automatically linear, affine and warp registered MRAs by four image quality parameters, including the vessel detection probability (VDP) in maximum intensity projection (MIP) images and contrast-to-noise ratios (CNR). The different registration types were compared by analysis of variance. Results: All studied image quality parameters showed similar trends. Generally, registration improved the leg MRA quality significantly (P < 0.05). The 12% of lower legs with a body shift of 1 mm or more showed the highest gain in image quality when using linear registration instead of no registration, with an average VDP gain of 20-49%. Warp registration improved the image quality slightly further. Conclusion: Automated image registration can improve the MRA image quality especially in the lower legs, which is comparable to the effect of pixel shift in DSA.

  5. From 3D to 4D: Integration of temporal information into CT angiography studies.

    Science.gov (United States)

    Haubenreisser, Holger; Bigdeli, Amir; Meyer, Mathias; Kremer, Thomas; Riester, Thomas; Kneser, Ulrich; Schoenberg, Stefan O; Henzler, Thomas

    2015-12-01

    CT angiography is the current clinical standard for the imaging many vascular illnesses. This is traditionally done with a single arterial contrast phase. However, advances in CT technology allow for a dynamic acquisition of the contrast bolus, thus adding temporal information to the examination. The aim of this article is to highlight the clinical possibilities of dynamic CTA using 2 examples. The accuracy of the detection and quantification of stenosis in patients with peripheral arterial occlusive disease, especially in stadium III and IV, is significantly improved when performing dynamic CTA examinations. The post-interventional follow-up of examinations of EVAR benefit from dynamic information, allowing for a higher sensitivity and specificity, as well as allowing more accurate classification of potential endoleaks. The described radiation dose for these dynamic examinations is low, but this can be further optimized by using lower tube voltages. There are a multitude of applications for dynamic CTA that need to be further explored in future studies.

  6. Operator radiation exposure during right or left transradial coronary angiography: A phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Sciahbasi, Alessandro, E-mail: alessandro.sciahbasi@fastwebnet.it [Interventional Cardiology, Sandro Pertini Hospital, Rome (Italy); Rigattieri, Stefano [Interventional Cardiology, Sandro Pertini Hospital, Rome (Italy); Sarandrea, Alessandro [HSE Management, Rome (Italy); Cera, Maria; Di Russo, Cristian; Fedele, Silvio [Interventional Cardiology, Sandro Pertini Hospital, Rome (Italy); Romano, Silvio [Cardiology, University of L’Aquila, Rome (Italy); Pugliese, Francesco Rocco [Emergency Department, Sandro Pertini Hospital, Rome (Italy); Penco, Maria [Cardiology, University of L’Aquila, Rome (Italy)

    2015-10-15

    Background: Previous studies showed a possible lower radiation dose absorbed by operators comparing LRA and RRA for percutaneous coronary procedures. The reasons of this lower radiation dose are not well known. The aim of this study was to evaluate the radiation dose absorbed by operators comparing left with right radial access (LRA and RRA respectively) during a simulated diagnostic coronary angiography using a phantom. Methods: A coronary angiography examination was simulated on a phantom by 5 operators using eight projections with 5 seconds fluoroscopy each. Each operator was equipped with 4 electronic dosimeters placed at thorax, at left wrist, at left head and at hip level. Radiation doses were expressed in picosievert and normalized by dose area product. Results: LRA compared to RRA was associated with a significant lower operator dose at wrist (36 pSv/cGYcm{sup 2} [IQR 18–59 pSv/cGYcm{sup 2}] and 48 pSv/cGYcm{sup 2} [IQR 22–148 pSv/cGYcm{sup 2}] respectively, p = 0.01) and thorax (3 pSv/cGYcm{sup 2} [IQR 2–5 pSv/cGYcm{sup 2}] and 10 pSv/cGYcm{sup 2} [6–23 pSv/cGYcm{sup 2}] respectively, p < 0.001) but with a significant higher radiation dose at hip level (102 pSv/cGYcm{sup 2} [IQR 44–199 pSv/cGYcm{sup 2}] and 67 pSv/cGYcm{sup 2} [IQR 39–132 pSv/cGYcm{sup 2}] respectively, p = 0.02). Conversely the radiation dose at left side of the head did not show significant differences between the two approaches. Conclusions: In this phantom study simulating a diagnostic coronarography the use of LRA compared to RRA was associated with a significant lower radiation dose at wrist and thorax but with an increased dose at hip level. Summary: To evaluate the radiation dose absorbed by operators comparing left with right radial access (LRA and RRA respectively) we simulated a diagnostic coronary angiography using a dedicated phantom. Operators were equipped with dedicated electronic dosimeters at wrist, hip, head and thorax level. LRA compared to RRA was

  7. Dexmedetomidine and propofol for cerebral angiography in non-intubated patients: A comparative study

    Directory of Open Access Journals (Sweden)

    Sujoy Banik

    2015-01-01

    Full Text Available Context: Patients posted for cerebral angiography may be restless and drowsy with high chance of inadvertent movements. Aims: The primary objective was to compare the incidence of inadvertent movements between propofol and dexmedetomidine groups. The secondary objectives include comparison of recovery time and characteristics, Steward′s score, and haemodynamic and respiratory parameters between the two groups. Settings and Design: Prospective, randomised, double-blind, pilot study. Materials and Methods: In all, 20 adult uncooperative, drowsy patients were randomised to dexmedetomidine (1 μg/kg bolus over 10 minutes followed by 0.3-0.7 μg/kg/hour infusion or propofol (100 μg/kg/min for 10 minutes followed by 25-75 μg/kg/min infusion. Rate of movement, success of sedation, haemodynamics, respiratory parameters, Steward′s recovery score and recovery time were recorded. Statistical analysis used: Repeated measures of analysis of variance, Mann-Whitney test, independent and paired t-tests, and Fisher test. Results: The median rate of movement was similar (1, P = 0.206 with success of sedation achieved in 7 (70% patients in Group D and 9 (90% patients in Group P, which was comparable (P = 0.582. The median recovery time in patients in Group D was 150 (37-764 seconds and in Group P was 128 (54-174 seconds (P = 0.519 with similar Steward′s scores (P = 0.363. Haemodynamics and respiratory variables were well-maintained during loading and maintenance dose infusions in both the groups. Conclusions: Dexmedetomidine is a safe alternative for diagnostic cerebral angiography. Its success of sedation, median rate of movement during the imaging procedure, haemodynamics, respiratory parameters, recovery time and Steward′s recovery score were similar to propofol in our study.

  8. Value of high spatial and high temporal resolution magnetic resonance angiography for differentiation between idiopathic and thromboembolic pulmonary hypertension: initial results

    Energy Technology Data Exchange (ETDEWEB)

    Ley, Sebastian; Eichinger, Monika [DKFZ, Department of Radiology (E010), Heidelberg (Germany); Johannes Gutenberg-University, Department of Radiology, University Hospital Mainz, Mainz (Germany); Fink, Christian; Zaporozhan, Julia; Puderbach, Michael; Plathow, Christian; Kauczor, Hans-Ulrich [DKFZ, Department of Radiology (E010), Heidelberg (Germany); Borst, Mathias M.; Meyer, F. Joachim; Gruenig, Ekkehard [University Heidelberg, Department of Internal Medicine, Heidelberg (Germany); Kreitner, Karl-Friedrich [Johannes Gutenberg-University, Department of Radiology, University Hospital Mainz, Mainz (Germany)

    2005-11-01

    Differentiation between different forms of pulmonary hypertension (PH) is essential for correct disease management. The goal of this study was to elucidate the clinical impact of high spatial resolution MR angiography (SR-MRA) and time-resolved MRA (TR-MRA) to differentiate between patients with chronic thromboembolic PH (CTEPH) and idiopathic pulmonary arterial hypertension (IPAH). Ten PH patients and five volunteers were examined. Twenty TR-MRA data sets (TA 1.5 s) and SR-MRA (TA 23 s) were acquired. TR-MRA data sets were subtracted as angiography and perfusion images. Evaluation comprised analysis of vascular pathologies on a segmental basis, detection of perfusion defects, and bronchial arteries by two readers in consensus. Technical evaluation comprised evaluation of image quality, signal-to-noise ratio (SNR) measurements, and contrast-media passage time. Visualization of the pulmonary arteries was possible down to a subsegmental (SR-MRA) and to a segmental (TR-MRA) level. SR-MRA outperformed TR-MRA in direct visualization of intravascular changes. Patients with IPAH predominantly showed tortuous pulmonary arteries while in CTEPH wall irregularities and abnormal proximal-to-distal tapering was found. Perfusion images showed a diffuse pattern in IPAH and focal defects in CTEPH. TR-MRA and SR-MRA resulted in the same final diagnosis. Both MRA techniques allowed for differentiation between IPAH and CTEPH. Therefore, TR-MRA can be used in the clinical setting, especially in dyspneic patients. (orig.)

  9. 短暂性脑缺血发作时磁共振血管成像病变特点%Lesion characteristics in magnetic resonance angiography imaging in transient ischemic attacks

    Institute of Scientific and Technical Information of China (English)

    董玉茹; 王宏; 钟心; 刘勉; 刘腾; 兰鹏宇; 杨斯娇

    2013-01-01

    目的 探讨短暂性脑缺血发作(transient ischemic attacks,TIA)时磁共振血管成像病变特点.方法 选取我院收治的60例TIA患者,行磁共振血管成像检查颅内动脉、颈部动脉,分析患者颅颈部供血动脉病变特点、狭窄情况.结果 磁共振检查发现脑供血动脉狭窄患者53例(88.33%),未见异常者7例(11.67%).其中,颈内动脉系统发现病变者40例(75.47%),椎基底动脉系统发现病变者13例(24.53%).不同动脉系统的病变在颅内外的分布无统计学差异(χ2=4.94,P=0.08470).53例发生狭窄病例中,共有病变动脉92支,其中轻度狭窄20支,中度32支,重度38支,2支闭塞;按发生支数依次排序为颈内动脉、大脑中动脉、椎动脉、颈总动脉、基底动脉、大脑前动脉起始段、大脑后动脉.结论 磁共振技术诊断TIA客观,综合患者临床情况对于制定治疗方案具有重要的临床意义.%Objective To study the lesion characteristics in magnetic resonance angiography imaging in transient ischemic attacks. Methods Sixty patients with transient ischemic attacks in this hospital were recruited to examine intracranial artery and carotid artery by magnetic resonance angiography. We analyzed the lesion characteristics of cranium — neck blood — supplying arteries, such as narrowing, and angiosclerosis. Results 53(88. 33% ) patients had cerebral artery stenosis and 7(11. 67% ) patients had nothing abnormal detected by magnetic resonance imaging. Forty patients had lesions in internal carotid artery system and 13 patients in vertebral basilar artery system. There was no significant difference in distribution of intracranial and extracranial lesions between different arterial systems, % =4. 94,P = 0. 08470. There were 92 arteries with lesions in 53 patients with cerebral artery stenosis; mild stenosis in 20 branches, moderate stenosis in 32 branches, severe stenosis 38 branch, occlusion 2 branch. The number of affected branches increased in the

  10. Catheter Angiography

    Medline Plus

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

  11. Catheter Angiography

    Medline Plus

    Full Text Available ... Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Catheter Angiography ... may eliminate the need for surgery. Tell your doctor if there's a possibility you are pregnant and ...

  12. Catheter Angiography

    Medline Plus

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

  13. Catheter Angiography

    Medline Plus

    Full Text Available ... images are captured using a small dose of ionizing radiation ( x-rays ). top of page What are some common uses of the procedure? Catheter angiography is used to examine blood vessels in key areas of the body, including the: brain neck heart chest abdomen (such as the kidneys ...

  14. Effectiveness of embolization for management of hemoptysis pulmonary tuberculosis: comparison of chest radiographic study and angiography

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sang Chul; Kim, Yong Ju; Park, Joong Wha; Lee Myeong Sub; Kim Dong Jin; Hong In Soo [Yonsei Univ. College of Medicine, Wonju (Korea, Republic of)

    2001-01-01

    To compare the effectiveness of embolization of the bronchial artery embolization for the management of hemoptysis in pulmonary tuberculosis cases with the severity of lung parenchymal injury and pleural infiltration, as seen on plain chest radiographs, and with the findings of angiography of the branchial artery. Among 265 patients with hemoptysis due to pulmonary tuberculosis, the findings of plain chest radiography and angiography of the bronchial artery were comparatively analyzed in the 206 for whom the results of follow up were available. The chest radiographin findings were classified as follows: Type I refers to simple pulmonary tuberculosis; Type II includes cases in which pulmonary tuberculosis is complicated by bronchiectasis, aspergillosis, or cavitation; Type III si either Types I or II acompainted by pleural in filtrates limited to the lung apex, and Type IV includes cases in which pleural infiltrates have extended beyond the apex in the whole the lung. Bronchial angiographic findings were divided into four groups: Group I consists of cases which show abnormalities of only the bronchial artery; Group II includes those in which abnormalities are seen in the bronchial artery and either the internal mammary or an intercostal artery; Group III comprises cases which belong to Group I or II and which a bronch of the subclavian artery is abnormal, and Group IV includes those in which abnormalities occur in at least two branches of the subclavian artery, or there is direct visualization of hypervascularity of this vessel. The initial post-embolic hemostatic effect and the results of follow up were studied over a six-month period. As compared with simple pulmonary tuberculosis (Type I), we found that as the severity of pleural infiltration and complications revealed by plain chest radiographs increased (Type II, III, IV), so did the severity of the manifestation of systemic collateral arteries other than the bronchial artery, as depicted by increased on

  15. Usefulness of magnetic resonance imaging (MRI) in the detection of the lesions of gestational trophoblastic disease; Comparison with computed tomography and digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Satoshi; Akahori, Taiichiro; Mochizuki, Matsuto; Kono, Michio (Kobe Univ. (Japan). School of Medicine)

    1992-02-01

    Twenty patients with gestational trophoblastic disease (GTN) were examined by magnetic resonance imaging (MRI), computed tomography (CT) and digital subtraction angiography (DSA), to evaluate their usefulness in the diagnosis of the disease. The lesions of hydatidiform mole were mainly composed of molar vesicles, dilated vessels and hemorrhage which were depicted as small round high intensity lesions on the T2-weighted images and as tree-like low intensity lesions and high or low intensity lesions of various shapes in the T1-, T2-weighted images. These MRI findings closely corresponded to the histopathological findings. On the other hand, CT findings obtained with hydatidiform mole were characterized by filling defects or a small round low density area on contrast enhanced images. The detection ratio for intramural lesions of invasive mole and choriocarcinoma by MRI was 83% (5/6), while that by CT was 50% (3/6). The obliteration of the junctional zone and interruption of the myometrium observed in MRI were significant signs suggesting intramural invasion of the disease. In fact, these signs in MRI were observed in all of the six cases of invasive mole or choriocarcinoma examined. In conclusion, MRI is a powerful means for the determining the intramural invasive mole and choriocarcinoma. Thus more accurate diagnosis of GTN will be obtained with the combined use of MRI and DSA. (author).

  16. The EXPLORE Trial: A Feasibility Study Using Fluorescence Angiography to Evaluate Perfusion in the Oxygen-Rich Environment.

    Science.gov (United States)

    Arnold, Jonathan F; Roscum, Melissa

    2016-10-26

    Hyperbaric oxygen therapy (HBOT) is defined as breathing 100% oxygen at a pressure ≥1.4 atmospheres absolute (ATA). Adjunct HBOT is one modality used for treatment of certain complex wounds. The resulting increase in oxygen delivery to wounded tissue has been associated with reduced edema, reduced inflammation, improved infection control, increased collagen deposition, and increased angiogenesis. However, there remains a relative paucity of evidence supporting the use of HBOT in the treatment of certain acute and chronic, non-healing wounds. This feasibility study was undertaken to evaluate the ability of fluorescence angiography to provide real-time visualization and objective assessment of changes in local tissue perfusion over a standard course of HBOT. This single-center, prospective, feasibility study included a total of 34 subjects with wounds of various etiologies deemed eligible for treatment with adjunct HBOT. Fluorescence angiography was performed pre- and post-HBOT sessions 1, 5, 10, 15, and 20. The imaging sequences were analyzed to determine the effects of HBOT on local tissue perfusion to the wounds. A total of 22 subjects received a minimum of 10 HBO sessions with associated pre- and post-fluorescence angiography performed and analyzed. Fluorescence angiography was able to provide both real-time visualization and objective assessment of changes in tissue perfusion over the course of adjunct HBOT. The results of this feasibility study suggest that serial fluorescence angiography can detect short- and long-term changes in wound area tissue perfusion associated with HBOT. These findings may assist in the selection and monitoring of patients undergoing HBOT.

  17. First-pass and high-resolution steady-state magnetic resonance angiography of the peripheral arteries with gadobenate dimeglumine: an assessment of feasibility and diagnostic performance.

    Science.gov (United States)

    Anzidei, Michele; Napoli, Alessandro; Zaccagna, Fulvio; Cavallo Marincola, Beatrice; Zini, Chiara; Kirchin, Miles A; Catalano, Carlo; Passariello, Roberto

    2011-05-01

    To assess the feasibility of combined first-pass (FP) and steady-state (SS) contrast-enhanced magnetic resonance angiography (MRA) of the peripheral arteries with gadobenate dimeglumine (MultiHance) and to evaluate diagnostic performance relative to digital subtraction angiography (DSA). A total of 35 patients with symptomatic peripheral arterial occlusive disease (PAOD) underwent FP MRA (repetition time [TR]/echo time [TE]/flip angle [FA]/acquisition time [TA] = 3.5/1.2/30°/14s) at 1.5T after intravenous injection of 10 mL of gadobenate dimeglumine. Thereafter, SS imaging of the calf (TR/TE/FA/TA = 7.5/2.3/20°/40-130s) and femoropopliteal (TR/TE/FA/TA = 7.5/2.3/18°/130-240s) regions was performed after a second injection of 5 mL of gadobenate dimeglumine. All patients underwent conventional DSA. Three readers reviewed separate FP and FP+SS MRA datasets for image quality and presence/absence of clinically relevant PAOD. A fourth independent observer evaluated DSA images. The diagnostic performance (sensitivity, specificity, positive and negative predictive values) achieved with each dataset was determined and compared. Inter-reader agreement was assessed using kappa statistics. The image quality of 134 of 140 vascular regions was optimal or adequate on SS MRA. Inter-reader agreement was good to very good for assessments of FP (κ = 0.725) and combined FP+SS images (κ = 0.866). SS images improved diagnostic confidence in 34 (48.6%) femoropoliteal and 46 (65.7%) crural regions and altered final diagnosis in 8 (11.4%) and 10 (14.3%) regions, respectively. Global diagnostic accuracy increased from 92.9% on FP images to 95.9% on FP+SS images, with significant (P = 0.0384) improvement in the crural region. SS MRA of the peripheral arteries is feasible with gadobenate dimeglumine and potentially improves diagnostic performance in patients with symptomatic PAOD.

  18. Evaluation of Peripheral Arterial Disease with Nonenhanced Quiescent-Interval Single-Shot MR Angiography

    Science.gov (United States)

    Hodnett, Philip A.; Koktzoglou, Ioannis; Davarpanah, Amir H.; Scanlon, Timothy G.; Collins, Jeremy D.; Sheehan, John J.; Dunkle, Eugene E.; Gupta, Navyash; Carr, James C.

    2011-01-01

    Purpose: To assess the diagnostic performance of quiescent-interval single-shot (QISS) magnetic resonance (MR) angiography, a nonenhanced two-dimensional electrocardiographically gated single-shot balanced steady-state free precession examination for the evaluation of symptomatic chronic lower limb ischemia. Materials and Methods: For this prospective institutional review board–approved, HIPAA-compliant study, the institutional review board waived the requirement for informed patient consent. The QISS nonenhanced MR angiography technique was evaluated in a two-center trial involving 53 patients referred for lower extremity MR angiography for suspected or known chronic peripheral arterial disease (PAD), with contrast material–enhanced MR angiography serving as the noninvasive reference standard. The accuracy of stenosis assessments performed with the nonenhanced MR angiography sequence was evaluated relative to the reference standard. Per-segment, per-region, and per-limb sensitivities and specificities were calculated, and assessments were considered correct only if they were in exact agreement with the reference standard–derived assessments. Generalized estimating equation (GEE) modeling with use of an unstructured binomial logit analysis was used to account for clustering of multiple measurements per case. The sensitivity and specificity of QISS MR angiography for the determination of nonsignificant (MR angiography was found to be nearly equivalent to the diagnostic performances of contrast-enhanced MR angiography and digital subtraction angiography. Non-GEE segment-based analysis revealed that for the two reviewers, nonenhanced MR angiography had sensitivities of 89.7% (436 of 486 segments) and 87.0% (423 of 486 segments) and specificities of 96.5% (994 of 1030 segments) and 94.6% (973 of 1028 segments). Conclusion: QISS nonenhanced MR angiography offers an alternative to currently used imaging tests for symptomatic chronic lower limb ischemia, for which

  19. Radiation protection to the eye and thyroid during diagnostic cerebral angiography: a phantom study.

    Science.gov (United States)

    Shortt, C P; Malone, L; Thornton, J; Brennan, P; Lee, M J

    2008-08-01

    We measured radiation doses to the eye and thyroid during diagnostic cerebral angiography to assess the effectiveness of bismuth and lead shields at dose reduction. Phantom head angiographic studies were performed with bismuth (study 1) and lead shields (study 2). In study 1 (12 phantoms), thermoluminescent dosimeters (TLD) were placed over the eyes and thyroid in three groups: (i) no shields (four phantoms); (ii) anterior bismuth shields (four phantoms) and (iii) anterior and posterior bismuth shields (four phantoms). In a second study (eight phantoms), lead shields were placed over the thyroid only and TLD dose measurements obtained in two groups: (i) no shielding (four phantoms) and (ii) thyroid lead shielding (four phantoms). A standard 4-vessel cerebral angiogram was performed on each phantom. Study 1 (bismuth shields) showed higher doses to the eyes compared with thyroid (mean 13.03 vs 5.98 mSv, P shielding did not significantly reduce dose to either eyes or thyroid in the measured TLD positions. In study 2, a significant thyroid dose reduction was found with the use of lead shields (47%, mean 2.46 vs 4.62 mSv, P shielding is impractical and interferes with diagnostic capability. Thyroid lead shielding yields significant protection to the thyroid, is not in the field of view and should be used routinely.

  20. Whole-body MR angiography with body coil acquisition at 3 T in patients with peripheral arterial disease using the contrast agent gadofosveset trisodium

    DEFF Research Database (Denmark)

    Nielsen, Yousef W; Eiberg, Jonas P; Løgager, Vibeke Berg;

    2009-01-01

    Whole-body magnetic resonance angiography (WB-MRA) at 3 T with body coil acquisition has not previously been investigated. In this study, WB-MRA was performed in this manner using the blood pool contrast agent gadofosveset trisodium.......Whole-body magnetic resonance angiography (WB-MRA) at 3 T with body coil acquisition has not previously been investigated. In this study, WB-MRA was performed in this manner using the blood pool contrast agent gadofosveset trisodium....

  1. 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

  2. MR angiography in abdominal neoplasms

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-10-01

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

  3. Study of Mode Coupling on Coaxial Resonators

    Institute of Scientific and Technical Information of China (English)

    Rui Liu; Hong-Fu Li

    2011-01-01

    A study of mode coupling phenomenon of coaxial resonators has been conducted with theories.Through establishing the source-free transmission line equation,boundary conditions of the coaxial resonators with a corrugated inner conductor are analyzed.In the end,calculations are performed in a wide range of corrugation parameters for the resonator of the Karisruhe Institute of Technology (KIT) relevant coaxial gyrotron.

  4. Carotid angiography

    Directory of Open Access Journals (Sweden)

    Arne Torkildsen

    1950-03-01

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

  5. Changes in susceptibility signs on serial T2*-weighted single-shot echo-planar gradient-echo images in acute embolic infarction: comparison with recanalization status on 3D time-of-flight magnetic resonance angiography

    Energy Technology Data Exchange (ETDEWEB)

    Shinohara, Yuki; Kinoshita, Toshibumi; Kinoshita, Fumiko [Research Institute of Brain and Blood Vessels - Akita, Department of Radiology, Akita (Japan)

    2012-05-15

    The present study compares changes in susceptibility signs on follow-up single-shot echo-planar gradient-echo T2*-weighted images (GRE-EPI) with vascular status on follow-up magnetic resonance angiography (MRA) in acute embolic infarction. Twenty consecutive patients with acute embolic infarction repeatedly underwent MR imaging including GRE-EPI and MRA using a 1.5-T MR superconducting system. All patients underwent initial MR examination within 24 h of onset and follow-up MR imaging within 1 month after onset. Changes in susceptibility signs on follow-up GRE-EPI were compatible with vascular status on follow-up MRA in 19 of the 20 patients. Susceptibility signs disappeared with complete recanalization in 13 patients, migrated with partial recanalization in 3, did not change together with the absence of recanalization in 2, and became extended together with the absence of recanalization in 1. Cerebral hemorrhage obscured susceptibility signs in the one remaining patient. Susceptibility signs on follow-up GRE-EPI can reflect changes in an acute embolus, such as recanalization or migration, in this study. Serial GRE-EPI in acute embolism complements the diagnostic certainty of MRA by directly detecting an embolus as a susceptibility sign. (orig.)

  6. Comparison of contrast and noncontrast magnetic resonance angiography for quantitative analysis of thoracic arteries in young patients with congenital heart defects

    Directory of Open Access Journals (Sweden)

    Pasqua Alessia

    2011-01-01

    Full Text Available Background : Contrast MRA (C-MRA is the standard for quantitative analysis of thoracic vessels. We evaluated a noncontrast MRA (NC-MRA sequence (3-D EKG and navigator-gated SSFP for quantitative evaluation of the thoracic aorta and branch pulmonary arteries in young patients with congenital heart disease. Objective : To compare contrast and noncontrast magnetic resonance angiography for quantitative analysis of thoracic arteries in young patients with congenital heart defects. Methods : Measurements of thoracic aorta and branch pulmonary arteries were obtained from C-MRA and NC-MRA images in 51 patients, ages 2-35 years. Vessel diameters were compared using correlation and Bland-Altman analysis. Interobserver variability was assessed using percent variation. Results : C-MRA and NC-MRA measurements were highly correlated (r = 0.91-0.98 except for the right pulmonary artery (r = 0.74, 0.78. Agreement of measurements was excellent (mean difference -0.07 to -0.53 mm; mean % difference -1.8 to -4.9% except for the right pulmonary artery which was less good (mean difference 0.73, -1.38 mm; -3, -10%. Interobserver variability ranged from 5% to 8% for aortic and from 10% to 16% for pulmonary artery measures. The worse agreement and greater variability of the pulmonary artery measures appears due to difficulty standardizing the measurements in patients with abnormal and irregular vessels. Conclusion : These data indicate that C-MRA and NC-MRA measures are comparable and could be used interchangeably, avoiding administration of contrast in selected patients.

  7. Preoperative planning of renal transplantation: a comparison of non-contrast-enhanced ultrasonography, computed tomography, and magnetic resonance angiography with observations from surgery.

    Science.gov (United States)

    Blankholm, Anne Dorte; Pedersen, Bodil G; Stausbøl-Grøn, Brian; Andersen, Gratien; Hørlyck, Arne; Østrat, Ernst Ø; Laustsen, Sussie; Ringgaard, Steffen

    2015-12-01

    Many candidates for kidney transplantation need to undergo vessel examination before the transplantation procedure. To identify the optimal preoperative modality for the examination of vessel status without the use of contrast agents in kidney transplant candidates. Fifty-three consecutive patients were examined and 31 patients were transplanted. Ultrasonography (US), non-contrast-enhanced computed tomography (NCCT), and non-contrast-enhanced magnetic resonance angiography (NCMRA) were compared using inspection during kidney transplantation (TX) as a reference standard. The sensitivity and specificity to severe arteriosclerotic changes and the accuracy were calculated. Kappa statistics were used to assess the agreement between TX and the different examination modalities, and McNemar's test was used to test for significant differences. US had higher sensitivity (1.0) and better agreement with observations from surgery (k = 0.89) than both NCCT (sensitivity = 0.60; k = 0.72) and NCMRA (sensitivity = 0.20; k = 0.30). No significant difference was found between TX and US (P = 0.3173) or TX and NCCT (P = 0.1573), but there was a significant difference between TX and NCMRA (P = 0.0455). US was inconclusive in 20% of cases, and the internal iliac artery could not be visualized in 69% of cases. Either US or NCCT can be used as the preferred preoperative imaging modality to examine vessel status before kidney transplantation, but a combination of the two is preferable. NCMRA should not be used as the sole imaging modality for preoperative imaging before kidney transplantation because of its low sensitivity in detecting severe arteriosclerotic disease without the presence of stenosis. © The Foundation Acta Radiologica 2014.

  8. A comparative study of the nephrotoxicity of iohexol, iopamidol and ioxaglate in peripheral angiography.

    Science.gov (United States)

    Campbell, D R; Flemming, B K; Mason, W F; Jackson, S A; Hirsch, D J; MacDonald, K J

    1990-06-01

    Iohexol (Omnipaque 350) and iopamidol (Isovue 370) are nonionic monomers; ioxaglate (Hexabrix 320) is an ionic dimer. We compared the nephrotoxicity of these three media by a prospective double-blind evaluation in 500 patients who underwent peripheral angiography during a 6-month period. Serum creatinine levels were determined before injection of the contrast medium and 72 hours after in 478 patients. In 308 (64%) patients there was an average increase in the serum creatinine level of 18.1 mumol/L after injection of an average volume of 123 ml of contrast medium. A subset of 80 patients who had an elevated baseline creatinine level (more than 110 mumol/L) had an average increase in the serum creatinine level of 40.45 mumol/L. Of patients who had arterial injections, 182 (72%) had an increase in serum creatinine level (20.7 mumol/L), but of those who had peripheral venous injections, only 43 (45%) had an elevated creatinine level (9.2 mumol/L), and of those who had central venous injections, 83 (63.8%) had an elevated level (17.0 mumol/L). In most patients elevation of the serum creatinine level was not of clinical importance. High-risk patients with an elevated serum creatinine level were found to be most vulnerable to contrast nephrotoxicity. Although mean differences were not statistically significant, there were consistent trends which suggested that ioxaglate was the least nephrotoxic of the three agents studied.

  9. Radiation protection to the eye and thyroid during diagnostic cerebral angiography: a phantom study.

    LENUS (Irish Health Repository)

    Shortt, C P

    2008-08-01

    We measured radiation doses to the eye and thyroid during diagnostic cerebral angiography to assess the effectiveness of bismuth and lead shields at dose reduction. Phantom head angiographic studies were performed with bismuth (study 1) and lead shields (study 2). In study 1 (12 phantoms), thermoluminescent dosimeters (TLD) were placed over the eyes and thyroid in three groups: (i) no shields (four phantoms); (ii) anterior bismuth shields (four phantoms) and (iii) anterior and posterior bismuth shields (four phantoms). In a second study (eight phantoms), lead shields were placed over the thyroid only and TLD dose measurements obtained in two groups: (i) no shielding (four phantoms) and (ii) thyroid lead shielding (four phantoms). A standard 4-vessel cerebral angiogram was performed on each phantom. Study 1 (bismuth shields) showed higher doses to the eyes compared with thyroid (mean 13.03 vs 5.98 mSv, P < 0.001) and a higher eye dose on the X-ray tube side. Overall, the use of bismuth shielding did not significantly reduce dose to either eyes or thyroid in the measured TLD positions. In study 2, a significant thyroid dose reduction was found with the use of lead shields (47%, mean 2.46 vs 4.62 mSv, P < 0.001). Considerable doses to the eyes and thyroid highlight the need for increased awareness of patient protection. Eye shielding is impractical and interferes with diagnostic capability. Thyroid lead shielding yields significant protection to the thyroid, is not in the field of view and should be used routinely.

  10. Clinical evaluation of magnetic resonance imaging in coronary heart disease: The CE-MARC study

    Directory of Open Access Journals (Sweden)

    Sculpher Mark

    2009-07-01

    Full Text Available Abstract Background Several investigations are currently available to establish the diagnosis of coronary heart disease (CHD. Of these, cardiovascular magnetic resonance (CMR offers the greatest information from a single test, allowing the assessment of myocardial function, perfusion, viability and coronary artery anatomy. However, data from large scale studies that prospectively evaluate the diagnostic accuracy of multi-parametric CMR for the detection of CHD in unselected populations are lacking, and there are few data on the performance of CMR compared with current diagnostic tests, its prognostic value and cost-effectiveness. Methods/design This is a prospective diagnostic accuracy cohort study of 750 patients referred to a cardiologist with suspected CHD. Exercise tolerance testing (ETT will be preformed if patients are physically able. Recruited patients will then undergo CMR and single photon emission tomography (SPECT followed in all patients by invasive X-ray coronary angiography. The order of the CMR and SPECT tests will be randomised. The CMR study will comprise rest and adenosine stress perfusion, cine imaging, late gadolinium enhancement and whole-heart MR coronary angiography. SPECT will use a gated stress/rest protocol. The primary objective of the study is to determine the diagnostic accuracy of CMR in detecting significant coronary stenosis, as defined by X-ray coronary angiography. Secondary objectives include an assessment of the prognostic value of CMR imaging, a comparison of its diagnostic accuracy against SPECT and ETT, and an assessment of cost-effectiveness. Discussion The CE-MARC study is a prospective, diagnostic accuracy cohort study of 750 patients assessing the performance of a multi-parametric CMR study in detecting CHD using invasive X-ray coronary angiography as the reference standard and comparing it with ETT and SPECT. Trial Registration Current Controlled Trials ISRCTN77246133

  11. Intraoperative assessment of STA-MCA bypass patency using near-infrared indocyanine green video-angiography: a preliminary study.

    Science.gov (United States)

    Ambekar, Sudheer; Babu, Arun; Pandey, Paritosh; Devi, Indira B

    2012-01-01

    Bypass patency is critical for patients undergoing superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis. Near-infrared indocyanine green video-angiography (ICGA) is an excellent method to assess vessels during cerebrovascular surgery. The aim of the present study is to analyze the effectiveness of ICGA in patients undergoing STA-MCA anastomosis for moyamoya disease. This study was a retrospective review of case records and operation records of patients who underwent STA-MCA bypass for moyamoya disease at our institute. Concordance of ICGA with intraoperative micro-Doppler and postoperative angiography, whenever available, was assessed. In all, 22 STA-MCA anastomoses were performed in 13 patients. ICGA was used to assess patency in 14 surgeries (10 patients). No patient required revision of anastomosis following ICGA. Postoperative angiography was done in five anastomoses (three patients) at three months follow-up and correlated well with ICGA findings in all cases. ICGA is an effective technique to assess bypass patency during cerebrovascular surgery. Routine use of ICGA in cerebral bypass surgery improves graft patency and minimizes complications due to graft occlusion.

  12. Intraoperative assessment of STA-MCA bypass patency using near-infrared indocyanine green video-angiography: A preliminary study

    Directory of Open Access Journals (Sweden)

    Sudheer Ambekar

    2012-01-01

    Full Text Available Background: Bypass patency is critical for patients undergoing superficial temporal artery-middle cerebral artery (STA-MCA anastomosis. Near-infrared indocyanine green video-angiography (ICGA is an excellent method to assess vessels during cerebrovascular surgery. Objective: The aim of the present study is to analyze the effectiveness of ICGA in patients undergoing STA-MCA anastomosis for moyamoya disease. Materials and Methods: This study was a retrospective review of case records and operation records of patients who underwent STA-MCA bypass for moyamoya disease at our institute. Concordance of ICGA with intraoperative micro-Doppler and postoperative angiography, whenever available, was assessed. Results: In all, 22 STA-MCA anastomoses were performed in 13 patients. ICGA was used to assess patency in 14 surgeries (10 patients. No patient required revision of anastomosis following ICGA. Postoperative angiography was done in five anastomoses (three patients at three months follow-up and correlated well with ICGA findings in all cases. Conclusion: ICGA is an effective technique to assess bypass patency during cerebrovascular surgery. Routine use of ICGA in cerebral bypass surgery improves graft patency and minimizes complications due to graft occlusion.

  13. Alpha resonant scattering for astrophysical reaction studies

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, H.; Kahl, D.; Nakao, T. [Center for Nuclear Study (CNS), University of Tokyo, RIKEN campus, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Wakabayashi, Y.; Kubano, S. [The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hashimoto, T. [Research Center for Nuclear Physics (RCNP), Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Hayakawa, S. [Istituto Nazionale Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS), Via S. Sofia 62, 95125 Catania (Italy); Kawabata, T. [Department of Physics, Kyoto University, Kita-Shirakawa, Kyoto 606-8502 (Japan); Iwasa, N. [Department of Physics, Tohoku University, Aoba, Sendai, Miyagi 980-8578 (Japan); Teranishi, T. [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan); Kwon, Y. K. [Institute for Basic Science, 70, Yuseong-daero 1689-gil, Yuseong-gu, Daejeon 305-811 (Korea, Republic of); Binh, D. N. [30 MeV Cyclotron Center, Tran Hung Dao Hospital, Hoan Kiem District, Hanoi (Viet Nam); Khiem, L. H.; Duy, N. G. [Institute of Physics, Vietnam Academy of Science and Technology, 18 Hong Quoc Viet, Nghia do, Hanoi (Viet Nam)

    2014-05-02

    Several alpha-induced astrophysical reactions have been studied at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. One of the methods to study them is the α resonant scattering using the thick-target method in inverse kinematics. Among the recent studies at CRIB, the measurement of {sup 7}Be+α resonant scattering is discussed. Based on the result of the experiment, we evaluated the contributions of high-lying resonances for the {sup 7}Be(α,γ) reaction, and proposed a new cluster band in {sup 11}C.

  14. Three-dimensional digital subtraction angiography vs two-dimensional digital subtraction angiography for detection of ruptured intracranial aneurysms: A study of 86 aneurysms

    Directory of Open Access Journals (Sweden)

    Kawashima Masatou

    2005-01-01

    Full Text Available Aims : Three-dimensional reconstruction of intracranial vessels is of interest for evaluation of aneurysms. This study determined diagnostic difference of three-dimensional digital subtraction angiography (3D-DSA, volume-rendering image versus 2D-DSA for evaluating ruptured intracranial aneurysms, particularly focusing on the size of aneurysms as depicted in both images. Settings and Design : Sixty-nine patients underwent 3D-DSA and 2D-DSA. The relative size of an aneurysm, which is the ratio of the maximal diameter of an aneurysm to the diameter of a major vessel, was compared between imaging techniques. In addition, relative sizes of smaller aneurysms (10 mm. Statistical analysis used : For comparison of aneurysm size and location of aneurysm, statistical analysis was performed with the Yates chi square test; statistical significance was set with a P value of less than 0.05. Results: Sixty-three (73.3% of the 86 total aneurysms were bigger when measured with 3D-DSA versus 2D-DSA. When measured with 3D-DSA, 28 (84.8% of the 33 smaller aneurysms were bigger, and 50% of the larger aneurysms were bigger versus measurements of 2D-DSA images ( P P Conclusions : 3D-DSA, especially volume-rendering images, tends to depict ruptured intracranial aneurysms bigger than 2D-DSA. This is particularly true with cerebral aneurysms that are <5 mm in size and are located in the anterior circulation, especially ICA and ACA territories.

  15. Comparison of conventional magnetic resonance imaging and nonenhanced three dimensional time-of-flight magnetic resonance angiography findings between dogs with meningioma and dogs with intracranial histiocytic sarcoma: 19 cases (2010-2014).

    Science.gov (United States)

    Ishikawa, Chieko; Ito, Daisuke; Kitagawa, Masato; Watari, Toshihiro

    2016-05-15

    OBJECTIVE To compare conventional MRI and nonenhanced 3-D time-of-flight (TOF) magnetic resonance angiography (MRA) findings between dogs with meningioma and dogs with intracranial histiocytic sarcoma (IHS). DESIGN Retrospective case series. ANIMALS 14 dogs with meningioma and 5 dogs with IHS. PROCEDURES Medical records of dogs with meningioma or IHS that were examined at a tertiary veterinary hospital from 2010 through 2014 and underwent 3-D TOF MRA in conjunction with conventional MRI were reviewed. Findings for conventional MRI and 3-D TOF MRA were compared between the 2 groups of dogs to evaluate whether there were any characteristics that could be used to differentiate meningioma from IHS. RESULTS Tumor type was significantly associated with signal intensity on conventional T2-weighted and fluid-attenuated inversion recovery MRI images; most meningiomas were hyperintense, and most IHSs were isointense or hypointense on those images. Tumor type was not associated with signal uniformity, tumor location, tumor origin, or the presence of edema, midline shift, or brain herniation. On MRA, blood vessels adjacent to the tumor were identified and characterized for 9 of 14 dogs with meningioma and all 5 dogs with IHS. Vessels adjacent to meningiomas were displaced in 8 of 9 dogs, whereas vessels adjacent to IHSs were not displaced. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated nonenhanced 3-D TOF MRA findings provided additional information that can be assessed in conjunction with conventional MRI findings to help differentiate meningiomas from IHSs in dogs.

  16. Randomized study on the safety and efficacy of dual-axis rotational versus standard coronary angiography in the Chinese population

    Institute of Scientific and Technical Information of China (English)

    LIU Hui-liang; JIN Zhi-geng; YANG Sheng-li; LUO Jian-ping; MA Dong-xing; LIU Ying; HAN Wei

    2012-01-01

    Background Dual-axis rotational coronary angiography (DARCA) was developed as an innovative adaptation of rotational angiography (RA),but it requires a longer coronary injection compared to standard coronary angiography (SA).As the body of the average Chinese patient is smaller than that of most western patients,with the same contrast injection time,the risk of complications from the contrast agent is increased in this population.The purpose of this study was to assess the clinical safety and efficacy of DARCA in the diagnosis of coronary artery disease (CAD) in the Chinese population by directly comparing it to SA.Methods Two hundred Chinese patients were randomized to either the SA group (n=100) or DARCA group (n=100).Contrast utilization,radiation exposure and procedure time were recorded for each modalities.Blood pressure (BP),heart rate (HR) pre and post injection symptoms and any arrhythmias were recorded.Results Compared to the SA group,there was a 42% reduction in contrast utilization,55% reduction in radiation exposure and a 31% shorter procedure time in the DARCA group.In both groups,there were slight declines in the systolic BP values in the left coronary artery (LCA) post injection (P <0.01).Moreover,post injection HRs for the LCA were also reduced in the DARCA group (P <0.01).But all of these changes were small,transient and without clinical importance.Only one patient (1%) in the DARCA group had an attack of ventricular tachycardia immediately post injection and it resolved by itself during LCA angiography.No arrhythmias occurred in the SA group.Conclusion DARCA is a safe,efficient,and clinically comparable altemative to SA in the diagnosis of coronary artery disease in the Chinese population with less contrast utilized,which is less radiation exposure and a shorter procedure time than SA.

  17. Expedited computed tomography perfusion and angiography in acute ischemic stroke: a feasibility study.

    Science.gov (United States)

    Gentile, Nina T; Cernetich, John; Kanamalla, Uday S; Kochan, Jeffrey P; Reimer, Hannah; Freeman, Brent; Jungreis, Charles

    2012-08-01

    Acute ischemic stroke diagnosis and treatment are among the most challenging in Emergency Medicine. Perfusion computed tomography (CTP) can increase the sensitivity for detecting ischemic stroke and, especially with the addition of CT angiography (CTA), improve decision-making regarding thrombolytic therapy compared to non-contrast computed tomography (NCCT) alone. However, because acute stroke protocols do not generally include procedures for multimodal imaging, they are not commonly performed. In addition, there is concern that additional studies could delay or preclude therapy in patients otherwise eligible for thrombolytic therapy. To demonstrate the feasibility of perfusion CTP and CTA in addition to NCCT of the brain in the emergency assessment of patients with acute ischemic stroke. Starting January 2008, multimodal (CTP and CTA) imaging was added to NCCT in the Emergency Department (ED) initial assessment of patients with stroke of ≤ 5 h duration. Over the subsequent 9 months, we measured the time from ED arrival to imaging and to recombinant tissue plasminogen activator (rt-PA) treatment and compared these times to patients evaluated with CT alone. From January to October 2008, 95 patients had CTP and CTA studies in addition to NCCT for acute ischemic stroke. There were no differences between the average time to CT study or to rt-PA treatment between patients evaluated with multimodal CT imaging and patients assessed with NCCT alone. Combining CTP and CTA with NCCT is feasible and does not adversely increase the time to CT imaging or rt-PA treatment in patients with acute ischemic stroke. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Direction of flow in posterior communicating artery on magnetic resonance angiography in patients with occipital lobe infarcts

    NARCIS (Netherlands)

    Jongen, JCF; Franke, CL; Ramos, LMP; Wilmink, JT; van Gijn, J

    2004-01-01

    Background and Purpose - In some people the blood supply to the posterior cerebral artery occurs partly or even exclusively via the carotid system. This anatomic configuration may influence the risk of occipital lobe infarction. We studied the presence and direction of flow in the posterior communic

  19. Three-dimensional CT angiography study on the relations between the vertebral artery and atlantoaxial joint

    Institute of Scientific and Technical Information of China (English)

    DUAN Shao-yin; LU Shao-mao; YE Feng; LIN Qing-chi; CHEN Liao-bin

    2009-01-01

    Background The vertebral artery (VA) and atlantoaxial joint (AAJ), with complicated structures, are located in the depths of the head-neck boundary area, the regional anatomy of which cannot be shown globally and directly. This study aims to evaluate three-dimensional CT angiography (3DCTA) in displaying the AAJ, atlantoaxial segment of the vertebral artery (ASVA) and the identification of their interrelations.Methods Sixty-eight subjects without pathology of the ASVA and AAJ were selected from head-neck CTA examination. All the 3D images were formed with volume rendering (VR) together with techniques of separating, fusing, opacifying and false-coloring (SFOF). On the 3D images, the ASVA and AAJ were observed, and their interrelations were measured.Results All the 3DCTA images were of high quality and up to our requirements. They could cleady and directly show the ASVA, ascending along the AAJ. There were 5 curves in the course of the ASVA, of which 2 curves were away from the atlantoaxial joint, one in the 2nd curve of 0.0 mm-5.4 mm, the other in the 4th of 2.6 mm-9.2 mm. There was no significant difference in the measurements between left and dght (P>0.05). The curved parts of the ASVA slightly expanded, with the biggest diameter of 5.6 mm in the 4th curve. Statistical comparison shows that the left ASVA is larger than the right (P<0.05). Variations of the ASVA were found in 8 cases and of the AAJ in 12.Conclusions 3DCTA can globally and directly demonstrate the structures of the AAJ, ASVA and their interrelations. The 3D imaging data make up and enrich the research contents of regional anatomy and lay the foundation for related study and applications.

  20. Effect of fluorescein angiography on renal functions in type 2 diabetes patients: A pilot study

    Directory of Open Access Journals (Sweden)

    Waleed H Almalki

    2017-01-01

    Full Text Available Fluorescein angiography (FA is an important tool for the diagnosis and management of diabetic retinopathy. However, the safety of fluorescein sodium on renal functions is not fully understood. One hundred type 2 diabetes patients, within the Ophthalmology Outpatient Clinic at Alexandria Main University Hospital, Egypt, were enrolled in this prospective observational study to determine the safety of FA on renal function. Serum creatinine and cystatin C were measured pre- and 2 days post-FA. Urinary neutrophil gelatinase-associated lipocalin (uNGAL was measured pre- and 4 hours post-FA. Renal injury was defined as a 25% increase in serum creatinine, cystatin C, or uNGAL. The study included 71 females and 29 males, with a mean age of 55.73 ± 7.29 years. Baseline serum cystatin C and uNGAL were 0.89 ± 0.34 mg/L and 21.7 ± 2.39 ng/mL, respectively. Serum cystatin C and uNGAL significantly increased after FA to 0.95 ± 0.36 and 27 ± 2.81, respectively (P <0.001. Eleven patients (11% experienced more than a 25% rise in serum cystatin C from baseline, whereas 40 patients (40% experienced more than a 25% increase in uNGAL levels after FA. However, the mean serum creatinine level did not change significantly after FA (P = 0.061. Only one patient experienced more than a 25% rise in serum creatinine from baseline. FA showed a significant increase in early sensitive acute kidney injury biomarkers (as serum cystatin C and uNGAL in substantial number of patients, suggesting but still not proving, a potential harmful effect of FA on kidney functions. These findings were not demonstrated using ordinary serum creatinine.

  1. Measurement precision and biological variation of cranial arteries using automated analysis of 3 T magnetic resonance angiography

    DEFF Research Database (Denmark)

    Amin, Faisal Mohammad; Lundholm, Elisabet; Hougaard, Anders;

    2014-01-01

    -to-day, and side-to-side variations of the circumference of the middle meningeal (MMA) and middle cerebral (MCA) arteries. RESULTS: We found an excellent intra- and interobserver agreement for the MMA (ICC: 0.909-0.987) and for the MCA (ICC: 0.876-0.949). The coefficient of variance within observers was ≤1......-to-day and side-to-side variations have not yet been published. We hypothesised that the observer related, side-to-side, and day-to-day variations would be less than 10%. METHODS: Ten female participants were studied using high-resolution MRA on two study days separated by at least one week. Using the automated...... LKEB-MRA vessel wall analysis software arterial circumferences were measured by blinded observers. Each artery was analysed twice by each of the two different observers. The primary endpoints were to determine the intraclass correlation coefficient (ICC) and intra- an inter-observer, the day...

  2. Can carotid stenosis be operated without arteriography? Contribution of magnetic resonance and helical computerized tomography angiography; Peut-on operer une stenose carotidienne sans arteriographie? Apport de l`angioMR et/ou de l`angioscanner helicoidal

    Energy Technology Data Exchange (ETDEWEB)

    Auffrau-Calvier, E.; Kersaint-Gilly, A. de; Desal, H.A.; Viarouge, M.P.; Havet, T. [Hopital Laennec, 44 - Nantes (France)

    1996-09-01

    The aim of this work is to ascertain the role of the magnetic resonance angiography (MRA) and to compare it with the Doppler effect, the X-ray angiography and the new method of helical computerized tomography. Seventy one carotid bifurcations in 37 patients with suspected cerebral vascular events has been evaluated with the MRA and digitalized angiography, the reference method. The obtained data corroborate the good results proposed by other authors reporting in the literature and allow to propose this examination as a new means of investigating carotid bifurcations. Work with the helical computerized tomography appears to be promising too but there are few reported series. Therefore, there appears to be two interesting points: the reliability of distinguishing between very severe stenosis and occlusion, and the fine-tuned analysis of the plaque with detection of ulcerations. When a consistent approach is used to the evaluation of the carotid bifurcation, the Willis circle and the cerebral parenchyma, the MRA can complete the Doppler echo data and the preoperative arteriography can only be used in patients when the MRA and the Doppler echo results disagree. (authors)

  3. Peripheral Reticular Pigmentary Degeneration and Choroidal Vascular Insufficiency, Studied by Ultra Wide-Field Fluorescein Angiography

    Science.gov (United States)

    Bae, Kunho; Cho, Kyuyeon; Kang, Se Woong; Kim, Sang Jin; Kim, Jong Min

    2017-01-01

    Purpose To explore the pathogenesis of peripheral reticular pigmentary degeneration (PRPD) and its clinical significance. Methods This cross-sectional, observational study (conducted between January 2010 and May 2015) enrolled 441 eyes of 229 subjects, including 35 eyes with PRPD and 406 eyes without PRPD, which was identified by ultra-wide-field fluorescein angiography (UWFA). The distribution and angiographic circulation time of PRPD were assessed by UWFA. The frequencies of systemic and ophthalmologic comorbidities were compared between groups. Univariate and multivariate generalized estimation equation methods were used to determine the risk factors for PRPD. Results The patients with PRPD had a mean age of 75.7 ± 8.5 years (range, 59–93 years), whereas the patients without PRPD had a mean age of 60.1 ± 14.9 years (range, 9–92 years). All eyes with PRPD manifested the lesion in the superior nasal periphery with or without circumferential extension. Among those, only 16 eyes (45.7%) in the PRPD group showed distinctive features in the same location on fundus photographs. There was significant choroidal filling delay in the PRPD group when compared with the control group (1.42±1.22 vs. -0.02±1.05 seconds, P < 0.001). Multivariate regression analysis revealed that older age (P < 0.001), stroke (P = 0.018), ischemic optic neuropathy (P < 0.001), and age-related macular degeneration (P = 0.022) were significantly associated with PRPD. Conclusions UWFA may enhance the diagnostic sensitivity of PRPD. Choroidal vascular insufficiency with compromised systemic circulation in the elderly was related to the manifestation of PRPD. These results help to better understand the pathophysiology of PRPD. Co-existence of systemic and ophthalmic circulatory disorders should be considered in patients with PRPD. PMID:28114409

  4. Non-enhanced magnetic resonance imaging of unruptured intracranial aneurysms at 7 Tesla: Comparison with digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Wrede, Karsten H.; Chen, Bixia [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, Department of Neurosurgery, Essen (Germany); Matsushige, Toshinori [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, Department of Neurosurgery, Essen (Germany); Hiroshima University, Department of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima (Japan); Goericke, Sophia L.; Umutlu, Lale; Forsting, Michael [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Quick, Harald H. [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, High Field and Hybrid MR Imaging, Essen (Germany); Ladd, Mark E. [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); German Cancer Research Center (DKFZ), Division of Medical Physics in Radiology (E020), Heidelberg (Germany); Johst, Soeren [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); Sure, Ulrich [University Hospital Essen, Department of Neurosurgery, Essen (Germany); Schlamann, Marc [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); University Hospital Giessen, Department of Neuroradiology, Giessen (Germany)

    2017-01-15

    To prospectively evaluate non-contrast-enhanced 7-Tesla (T) MRA for delineation of unruptured intracranial aneurysms (UIAs) in comparison with DSA. Forty patients with single or multiple UIAs were enrolled in this IRB-approved trial. Sequences acquired at 7 T were TOF MRA and non-contrast-enhanced MPRAGE. All patients additionally underwent 3D rotational DSA. Two neuroradiologists individually analysed the following aneurysm and image features on a five-point scale in 2D and 3D image reconstructions: delineation of parent vessel, dome and neck; overall image quality; presence of artefacts. Interobserver accordance was assessed by the kappa coefficient. A total of 64 UIAs were detected in DSA and in all 2D and 3D MRA image reconstructions. Ratings showed comparable results for DSA and 7-T MRA when considering all image reconstructions. Highest ratings for individual image reconstructions were given for 2D MPRAGE and 3D TOF MRA. Interobserver accordance was almost perfect for the majority of ratings. This study demonstrates excellent delineation of UIAs using 7-T MRA within a clinical setting comparable to the gold standard, DSA. The combination of 7-T non-enhanced MPRAGE and TOF MRA for assessment of untreated UIAs is a promising clinical application of ultra-high-field MRA. (orig.)

  5. Cardiac magnetic resonance angiography using blood-pool contrast agents: comparison of citrate-coated very small superparamagnetic iron oxide particles with gadofosveset trisodium in pigs.

    Science.gov (United States)

    Schnorr, J; Taupitz, M; Schellenberger, E A; Warmuth, C; Fahlenkamp, U L; Wagner, S; Kaufels, N; Wagner, M

    2012-02-01

    To compare citrate-coated very small superparamagnetic iron oxide particles (VSOP) with gadofosveset trisodium as blood pool contrast agents for cardiac magnetic resonance angiography (CMRA) in pigs. Animal experiments were approved by the responsible authority. 10 CMRA-like examinations were performed at 1.5 T after administration of VSOP (0.06  mmol Fe/kg; 5 examinations) and gadofosveset trisodium (0.03  mmol Gd/kg; 5 examinations). The CMRA protocol included ECG-gated inversion-recovery-prepared T1-weighted gradient echo imaging (IR-GRE; one slice) and ECG-gated inversion recovery prepared steady state free precession imaging (IR SSFP; one slice) before and 1, 3, 5, 10, 15, 20, 25, 30, 40, 50, and 60  min after injection. At each time point, three different inversion times (TI; 200  msec, 300  msec, and 400  msec) were applied. Contrast-to-noise ratios (CNR) between blood and myocardium were calculated and compared using mixed linear models. No significant differences of CNR were found between IR-GRE and IR SSFP. At 3 and 5  min after contrast agent administration, VSOP showed a significantly higher CNR than gadofosveset trisodium when TI of 200  msec and 300 msec were applied (TI of 200  msec at 3 min: 8.2 ± 0.7 vs. 5.4 ± 0.7; TI of 200  msec at 5 min: 7.9 ± 0.7 vs. 3.5 ± 0.8; TI of 300  msec at 3  min: 11.7 ± 0.7 vs. 8.8 ± 0.8; TI of 300  msec at 5  min: 11.4 ± 0.7 vs. 8.0 ± 0.8; p VSOP were found for all time points from 10 to 40  min irrespective of TI (p VSOP has superior blood-pool properties compared to gadofosveset trisodium resulting in prolonged improvement of CNR on CMRA. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Cardiac magnetic resonance angiography using blood-pool contrast agents. Comparison of citrate-coated very small superparamagnetic iron oxide particles with gadofosveset trisodium in pigs

    Energy Technology Data Exchange (ETDEWEB)

    Schnorr, J.; Taupitz, M.; Schellenberger, E.A.; Warmuth, C.; Wagner, S.; Kaufels, N.; Wagner, M. [Charite - Universitaetsmedizin Berlin (Germany). Inst. fuer Radiologie; Fahlenkamp, U.L. [Charite - Universitaetsmedizin Berlin (Germany). Inst. fuer Radiologie; Universitaetsklinikum Bonn (Germany). Radiologische Klinik

    2012-02-15

    Purpose: To compare citrate-coated very small superparamagnetic iron oxide particles (VSOP) with gadofosveset trisodium as blood pool contrast agents for cardiac magnetic resonance angiography (CMRA) in pigs. Materials and Methods: Animal experiments were approved by the responsible authority. 10 CMRA-like examinations were performed at 1.5 T after administration of VSOP (0.06 mmol Fe/kg; 5 examinations) and gadofosveset trisodium (0.03 mmol Gd/kg; 5 examinations). The CMRA protocol included ECG-gated inversion-recovery-prepared T1-weighted gradient echo imaging (IR-GRE; one slice) and ECG-gated inversion recovery prepared steady state free precession imaging (IR SSFP; one slice) before and 1, 3, 5, 10, 15, 20, 25, 30, 40, 50, and 60 min after injection. At each time point, three different inversion times (TI; 200 msec, 300 msec, and 400 msec) were applied. Contrast-to-noise ratios (CNR) between blood and myocardium were calculated and compared using mixed linear models. Results: No significant differences of CNR were found between IR-GRE and IR SSFP. At 3 and 5 min after contrast agent administration, VSOP showed a significantly higher CNR than gadofosveset trisodium when TI of 200 msec and 300 msec were applied (TI of 200 msec at 3 min: 8.2 {+-} 0.7 vs. 5.4 {+-} 0.7; TI of 200 msec at 5 min: 7.9 {+-} 0.7 vs. 3.5 {+-} 0.8; TI of 300 msec at 3 min: 11.7 {+-} 0.7 vs. 8.8 {+-} 0.8; TI of 300 msec at 5 min: 11.4 {+-} 0.7 vs. 8.0 {+-} 0.8; p < 0.05). Moreover, significant differences in favor of VSOP were found for all time points from 10 to 40 min irrespective of TI (p < 0.05). Conclusion: VSOP has superior blood-pool properties compared to gadofosveset trisodium resulting in prolonged improvement of CNR on CMRA. (orig.)

  7. Value of first day angiography/angioplasty in evolving Non-ST segment elevation myocardial infarction: an open multicenter randomized trial. The VINO Study.

    Science.gov (United States)

    Spacek, R; Widimský, P; Straka, Z; Jiresová, E; Dvorák, J; Polásek, R; Karel, I; Jirmár, R; Lisa, L; Budesínský, T; Málek, F; Stanka, P

    2002-02-01

    Direct angioplasty is an effective treatment for ST-elevation myocardial infarction. The role of very early angioplasty in non-ST-elevation infarction is not known. Thus, a randomized study of first day angiography/angioplasty vs early conservative therapy of evolving myocardial infarction without persistent ST-elevation was conducted. One hundred and thirty-one patients with confirmed acute myocardial infarction without ST-segment elevations were randomized within 24 h of last rest chest pain: 64 in the first day angiography/angioplasty group and 67 in the early conservative group (coronary angiography only after recurrent or stress induced myocardial ischaemia). All patients in the invasive group underwent coronary angiography on the day of admission (mean randomization-angiography time 6.2 h). First day angioplasty of the infarct related artery was performed in 47% of the patients and bypass surgery in 35%. In the conservative group, 55% underwent coronary angiography, 10% angioplasty and 30% bypass surgery within 6 months. The primary end-point (death/reinfarction) at 6 months occurred in 6.2% vs 22.3% (P<0.001). Six month mortality in the first day angiography/angioplasty group was 3.1% vs 13.4% in the conservative group (P<0.03). Non-fatal reinfarction occurred in 3.1% vs. 14.9% (P<0.02). First day coronary angiography followed by angioplasty whenever possible reduces mortality and reinfarction in evolving myocardial infarction without persistent ST-elevation, in comparison with an early conservative treatment strategy. Copyright 2001 The European Society of Cardiology.

  8. Alterações parenquimatosas na trombose venosa cerebral: aspectos da ressonância magnética e da angiorressonância Parenchymal abnormalities in cerebral venous thrombosis: findings of magnetic resonance imaging and magnetic resonance angiography

    Directory of Open Access Journals (Sweden)

    Clécia Santos Ferreira

    2006-10-01

    -mortalidade da doença.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.

  9. SS-HORSE method for studying resonances

    Science.gov (United States)

    Blokhintsev, L. D.; Mazur, A. I.; Mazur, I. A.; Savin, D. A.; Shirokov, A. M.

    2017-03-01

    A new method for analyzing resonance states based on the Harmonic-Oscillator Representation of Scattering Equations (HORSE) formalism and analytic properties of partial-wave scattering amplitudes is proposed. The method is tested by applying it to the model problem of neutral-particle scattering and can be used to study resonance states on the basis of microscopic calculations performed within various versions of the shell model.

  10. SS-HORSE method for studying resonances

    Energy Technology Data Exchange (ETDEWEB)

    Blokhintsev, L. D. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Mazur, A. I.; Mazur, I. A., E-mail: 008043@pnu.edu.ru [Pacific National University (Russian Federation); Savin, D. A.; Shirokov, A. M. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

    2017-03-15

    A new method for analyzing resonance states based on the Harmonic-Oscillator Representation of Scattering Equations (HORSE) formalism and analytic properties of partial-wave scattering amplitudes is proposed. The method is tested by applying it to the model problem of neutral-particle scattering and can be used to study resonance states on the basis of microscopic calculations performed within various versions of the shell model.

  11. A double-blind study comparing the safety, tolerability, and efficacy of ioversol 320 and iopamidol-300 in cerebral angiography.

    Science.gov (United States)

    Ringel, K; Kuehn, J

    1989-06-01

    Ioversol is a new nonionic, triiodinated, water-soluble contrast medium. In a controlled double-blind study, ioversol 320 versus iopamidol-300 was tested on 60 patients in cerebral angiography. The safety of the contrast medium, the general and local tolerance, as well as the contrast quality were tested. In this study, ioversol 320 displayed no differences from iopamidol-300 in terms of contrast quality, neurologic status, and liver and kidney tolerance. In the local tolerance test, patients receiving ioversol 320 perceived significantly less heat than patients receiving iopamidol-300 when all injections were considered.

  12. Whole-body magnetic resonance angiography with additional steady-state acquisition of the infragenicular arteries in patients with peripheral arterial disease

    DEFF Research Database (Denmark)

    Nielsen, Yousef W; Eiberg, Jonas P; Løgager, Vibeke B

    2010-01-01

    -body (WB) MRA. Twenty consecutive patients with PAD referred to digital-subtraction angiography (DSA) underwent WB-MRA. Using a bolus-chase technique, first-pass WB-MRA was performed from the supra-aortic vessels to the ankles. The blood-pool contrast agent gadofosveset trisodium was used at a dose of 0...

  13. Vascular flow density in pathological myopia: an optical coherence tomography angiography study.

    Science.gov (United States)

    Mo, Jing; Duan, Anli; Chan, Szyyann; Wang, Xuefei; Wei, Wenbin

    2017-02-03

    To investigate vascular flow density in pathological myopia with optical coherence tomography (OCT) angiography. A prospective comparative study was conducted from December 2015 to March 2016. Participants were recruited in Beijing Tongren Hospital. A total of 131 eyes were enrolled, which were divided into three groups: 45 eyes with emmetropia (EM; mean spherical equivalent (MSE) 0.50D to -0.50D), 41 eyes with high myopia (HM; MSE ≤-6.00D, without pathological changes), and 45 eyes with pathological myopia (PM; MSE ≤-6.00D and axial length (AL) ≥26.5 mm, and with pathological changes). Macular, choriocapillaris and radial peripapillary capillary (RPC) flow densities were measured and compared between groups, and their relationships with AL and best corrected visual acuity (BCVA) were analysed. Significant differences were found in macular, choriocapillaris and RPC flow densities among the three groups (pdensities of the PM group were significantly decreased (pdensity was found between the PM and HM groups (p=0.731). Compared with the EM group, retinal flow density in the macular and arcuate fibre region was not decreased in the HM group. In addition, there was a negative correlation between AL and superficial macular flow density (β=-0.542, pdensity (β=-0.282, p=0.002) and RPC flow density (β=-0.522, pdensity (β=0.194, p=0.021), deep macular flow density (β=0.373, pdensity (β=0.291, p=0.001). Macular and RPC flow densities decreased in pathological myopia compared with high myopia and emmetropia. No significant decrease of retinal flow density in the macular and arcuate fibre region was found in high myopic eyes compared with emmetropic eyes. Moreover, macular and RPC flow densities were negatively related to AL, and macular flow density was positively related to BCVA. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  14. TIPIT: A randomised controlled trial of thyroxine in preterm infants under 28 weeks gestation: Magnetic Resonance Imaging and Magnetic Resonance Angiography protocol

    Directory of Open Access Journals (Sweden)

    Tietze Anna

    2008-06-01

    Full Text Available Abstract Background Infants born at extreme prematurity are at high risk of developmental disability. A major risk factor for disability is having a low level of thyroid hormone described as hypothyroxinaemia, which is recognised to be a frequent phenomenon in these infants. Derangements of critical thyroid function during the sensitive window in prematurity when early development occurs, may have a range of long term effects for brain development. Further research in preterm infants using neuroimaging techniques will increase our understanding of the specificity of the effects of hypothyroxinaemia on the developing foetal brain. This is an explanatory double blinded randomised controlled trial which is aimed to assess the effect of thyroid hormone supplementation on brain size, key brain structures, extent of myelination, white matter integrity and vessel morphology, somatic growth and the hypothalamic-pituitary-adrenal axis. Methods The study is a multi-centred double blinded randomised controlled trial of thyroid hormone supplementation in babies born below 28 weeks' gestation. All infants will receive either levothyroxine or placebo until 32 weeks corrected gestational age. The primary outcomes will be width of the sub-arachnoid space measured using cranial ultrasound and head circumference at 36 weeks corrected gestational age. The secondary outcomes will be thyroid hormone concentrations, the hypothalamic pituitary axis status and auxological data between birth and expected date of delivery; thyroid gland volume, brain size, volumes of key brain structures, extent of myelination and brain vessel morphology at expected date of delivery and markers of morbidity which include duration of mechanical ventilation and/or oxygen requirement and chronic lung disease. Trial registration Current Controlled Trials ISRCTN89493983

  15. Renal artery assessment with nonenhanced steady-state free precession versus contrast-enhanced MR angiography.

    Science.gov (United States)

    Wyttenbach, Rolf; Braghetti, Antonio; Wyss, Michael; Alerci, Mario; Briner, Lukas; Santini, Paolo; Cozzi, Luca; Di Valentino, Marcello; Katoh, Marcus; Marone, Claudio; Vock, Peter; Gallino, Augusto

    2007-10-01

    To prospectively assess the diagnostic accuracy of nonenhanced three-dimensional (3D) steady-state free precession (SSFP) magnetic resonance (MR) angiography for detection of renal artery stenosis (RAS), with breath-hold contrast material-enhanced MR angiography performed as the reference standard. The study was local ethics committee approved; all patients gave written informed consent. Fifty-three patients (30 male, 23 female; mean age, 58 years) with arterial hypertension and suspected of having RAS were examined with 1.5-T 3D SSFP renal MR angiography. Stenosis grade, maximal visible vessel length, and subjective image quality were compared. Sensitivity, specificity, accuracy, and negative predictive value (NPV) were calculated on artery-by-artery and patient-by-patient bases. The significance of the results was assessed with the paired two-sided t test for continuous variables and with the marginal homogeneity test for categorical variables. Cohen kappa statistics were used to estimate interobserver agreement. One hundred eight renal arteries with 20 significant (>or=50%) stenoses were detected with contrast-enhanced MR angiography. At artery-by-artery analysis, sensitivity, specificity, accuracy, and NPV of nonenhanced SSFP MR angiography for RAS detection were 100%, 93%, 94%, and 100%, respectively, for observer 1 and 95%, 95%, 95%, and 99%, respectively, for observer 2. Corresponding patient-by-patient values were 100%, 92%, 94%, and 100%, respectively, for observer 1 and 100%, 95%, 96%, and 100%, respectively, for observer 2. Overestimation of stenosis grade with SSFP MR angiography resulted in six and four false-positive findings for readers 1 and 2, respectively. Mean maximal visible lengths of the renal arteries were 69.9 mm at contrast-enhanced MR angiography and 61.1 mm at SSFP MR angiography (PMR angiography had high sensitivity, specificity, accuracy, and NPV for RAS detection, without the need for contrast material. However, RAS severity was

  16. Iodixanol Has a Favourable Fibrinolytic Profile Compared to Iohexol in Cardiac Patients Undergoing Elective Angiography: A Double-Blind, Randomized, Parallel Group Study.

    Directory of Open Access Journals (Sweden)

    Andrew T Treweeke

    Full Text Available There is no consensus and a limited evidence base for choice of contrast agents (CA in angiography. This study evaluated the impact of iohexol and iodixanol CA on fibrinolytic factors (tissue plasminogen activator [t-PA] and plasminogen activator inhibitor-1 [PAI-1], as well as platelet-monocyte conjugates in cardiac patients undergoing elective angiography in a double-blind, randomised parallel group study.Patients (men, 50-70 years old; n = 12 were randomised to receive either iohexol (Omnipaque; n = 6 or iodixanol (Visipaque; n = 6 during elective angiography at Raigmore Hospital, Inverness, UK. Arterial and venous blood samples were drawn prior to CA delivery and following angiography. Assessment of platelet-monocyte conjugation, t-PA and PAI-1 antigen and activity was conducted in samples pre- and post-angiography.Plasma t-PA antigen was depressed equally in the study groups after angiography, but there was a greater reduction in PAI-1 antigen in the group receiving iodixanol. These findings corresponded to a substantial reduction in t-PA activity in patients receiving iohexol, with no change in those receiving iodixanol (P = 0.023 between the CA groups. Both CAs caused a reduction in platelet-monocyte conjugation, with no difference between the groups. No adverse events were reported during the trial.Avoiding reduced plasma t-PA activity might be an important consideration in choosing iodixanol over iohexol in patients at risk of thrombosis following angiography. The trial is registered on the ISRCTN register (ISRCTN51509735 and funded by the Coronary Thrombosis Trust and National Health Service (Highland R&D Endowments. The funders had no influence over study design or reporting.Controlled-Trials.com ISRCTN51509735.

  17. Gadolinium-enhanced magnetic resonance angiography for hepato mesenteric vascular evaluation: single and double doses comparison in schistosomiasis patients; Estudo da circulacao hepatomesenterica pela angiografia por ressonancia magnetica com gadolinio: comparacao entre doses simples e dupla no estudo de pacientes esquistossomoticos

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-15

    Objective: to evaluate the visibility of hepatomesenteric vascular segments by 3D gadolinium-enhanced magnetic resonance (MR) angiography and to compare the method effectiveness between two different gadolinium doses (single and double doses). Materials and methods: a prospective study was performed with 36 schistosomiasis patients who were submitted to 3D contrast-enhanced MR angiography. Scans were performed in a high-field equipment (1.5 T), with body coil and power injector for intravenous contrast administration. Contrast double doses (Gd-DTPA 0.2 mmol/kg) and single doses (0.1 mmol/kg) were randomly used respectively in 21 and 15 patients. Studies were interpreted by consensus between two observers who have rated the visualization degree of 25 proximal vascular segments without knowing the dose used. Results: proximal and calibrous vascular segments have presented higher visualization degree in the greatest part of the sample studied. The celiac trunk, common hepatic artery, splenic artery, proximal and medium third of superior mesenteric artery, portal vein, splenic vein and superior mesenteric vein have presented grade 2 visualization in more than 70% of the sample studied. As regards comparison between different doses, there was no significant difference (p < 0.05) in the visualization degree of several structures evaluated, between double dose and single dose groups, except for an isolate case of evaluation of right hepatic artery (p = 0.008) in which the single dose group has presented a higher frequency of grade 2 visualization with statistical significance. Conclusion: the visualization degree of hepato mesenteric vascular segments by 3D gadolinium-enhanced MR angiography is high, especially in the proximal and calibrous segments. The comparison between groups using single and double contrast doses has demonstrated similar results. (author)

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

    Directory of Open Access Journals (Sweden)

    Alexander Radbruch

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

  19. Studies on intracranial collateral circulation with multi-slice CT angiography in patients with symptomatic cerebral artery stenosis

    Directory of Open Access Journals (Sweden)

    Shu-qing ZHOU

    2011-06-01

    Full Text Available Objective To explore the features of intracranial collateral circulation in patients with symptomatic cerebral artery stenosis.Method Ninety-four patients with ischemic cerebrovascular disease admitted from Apr.2004 to Jun.2009 were involved in present study.All the patients were examined with cerebral multi-slice CT angiography,and the features of cerebral artery stenosis and intracranial collateral circulation were evaluated using maximum intensity projection(MIP and volume rendering(VR images of CT angiography.Result Of the 94 patients involved,48 were diagnosed as cerebral artery stenosis,including 29 cases of cerebral infarction,18 of transient ischemic attack(TIA and 1 of moyamoya disease(MMD.Among the 14 cases of severe cerebral artery stenosis or occlusion,cerebral infarction was found in 6 cases with lesser intracranial collateral vessels(including massive cerebral infarction in 4 cases and watershed infarction in 2 cases,and focal infarction of central semi-ovale in 1 case and TIA in 7 cases were found with abundant intracranial collateral vessels.Multiple lacunar infarction was found in 22 cases of mild or moderate cerebral artery stenosis,but there was no significant correlation between the stenosed arteries and infarction sites.Abundant intracranial collateral vessels were found in one patient with Moyamoya disease but no infarction was observed.Conclusions Intracranial collateral circulation plays an important role of compensation in patients with severe cerebral artery stenosis or occlusion.Cerebral angiography with multi-slice CT is of great significance in evaluation of cerebral artery stenosis and intracranial collateral circulation.

  20. Diagnostic accuracy of combined coronary angiography and adenosine stress myocardial perfusion imaging using 320-detector computed tomography: pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Nasis, Arthur; Ko, Brian S.; Leung, Michael C.; Antonis, Paul R.; Wong, Dennis T.; Kyi, Leo; Cameron, James D.; Meredith, Ian T.; Seneviratne, Sujith K. [Southern Health and Monash University, Monash Cardiovascular Research Centre, Monash Heart, Department of Medicine Monash Medical Centre (MMC), Melbourne (Australia); Nandurkar, Dee; Troupis, John M. [MMC, Southern Health, Department of Diagnostic Imaging, Melbourne (Australia)

    2013-07-15

    To determine the diagnostic accuracy of combined 320-detector row computed tomography coronary angiography (CTA) and adenosine stress CT myocardial perfusion imaging (CTP) in detecting perfusion abnormalities caused by obstructive coronary artery disease (CAD). Twenty patients with suspected CAD who underwent initial investigation with single-photon-emission computed tomography myocardial perfusion imaging (SPECT-MPI) were recruited and underwent prospectively-gated 320-detector CTA/CTP and invasive angiography. Two blinded cardiologists evaluated invasive angiography images quantitatively (QCA). A blinded nuclear physician analysed SPECT-MPI images for fixed and reversible perfusion defects. Two blinded cardiologists assessed CTA/CTP studies qualitatively. Vessels/territories with both >50 % stenosis on QCA and corresponding perfusion defect on SPECT-MPI were defined as ischaemic and formed the reference standard. All patients completed the CTA/CTP protocol with diagnostic image quality. Of 60 vessels/territories, 17 (28 %) were ischaemic according to QCA/SPECT-MPI criteria. Sensitivity, specificity, PPV, NPV and area under the ROC curve for CTA/CTP was 94 %, 98 %, 94 %, 98 % and 0.96 (P < 0.001) on a per-vessel/territory basis. Mean CTA/CTP radiation dose was 9.2 {+-} 7.4 mSv compared with 13.2 {+-} 2.2 mSv for SPECT-MPI (P < 0.001). Combined 320-detector CTA/CTP is accurate in identifying obstructive CAD causing perfusion abnormalities compared with combined QCA/SPECT-MPI, achieved with lower radiation dose than SPECT-MPI. (orig.)

  1. A clinico-radiological study on 254 cases of pontine high signals on magnetic resonance imaging in relation to brain stem semiology

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Masaki; Takahashi, Akira (Nagoya Univ. (Japan). Faculty of Medicine); Arahata, Yutaka; Motegi, Yoshimasa; Furuse, Masahiro

    1993-11-01

    A total of 254 patients who were proved to have pontine high intensity areas on T[sub 2]-weighted magnetic resonance imaging (MRI) were analyzed in relation to brain stem semiology. A comparative study on MRI and MR angiography was made between 254 patients with pontine high signals and 276 control cases showing no abnormality either on T[sub 1] or T[sub 2]-weighted images. Of the 254 patients, 62 had transient subjective complaints such as vertigo-dizziness. Supratentorial high signals, basilar artery tortuousness and vertebral artery asymmetry on MR angiography were seen more frequently in patients with pontine high signals than in the controls. In conclusion, pontine high signals may result from diffuse arteriosclerosis and MR angiography is considered to be a useful screening method. (author).

  2. Electrodynamic study of YIG filters and resonators

    Science.gov (United States)

    Krupka, Jerzy; Salski, Bartlomiej; Kopyt, Pawel; Gwarek, Wojciech

    2016-01-01

    Numerical solutions of coupled Maxwell and Landau-Lifshitz-Gilbert equations for a magnetized yttrium iron garnet (YIG) sphere acting as a one-stage filter are presented. The filter is analysed using finite-difference time-domain technique. Contrary to the state of the art, the study shows that the maximum electromagnetic power transmission through the YIG filter occurs at the frequency of the magnetic plasmon resonance with the effective permeability of the gyromagnetic medium μr ≈ −2, and not at a ferromagnetic resonance frequency. Such a new understanding of the YIG filter operation, makes it one of the most commonly used single-negative plasmonic metamaterials. The frequency of maximum transmission is also found to weakly depend on the size of the YIG sphere. An analytic electromagnetic analysis of resonances in a YIG sphere is performed for circularly polarized electromagnetic fields. The YIG sphere is situated in a free space and in a large spherical cavity. The study demonstrates that both volume resonances and magnetic plasmon resonances can be solutions of the same transcendental equations. PMID:27698467

  3. Cone-beam CT angiography of the thorax. An experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Katsuya; Shimada, Kazuhiro [Chiba Univ. (Japan). School of Medicine; Tadokoro, Hiroyuki (and others)

    1999-10-01

    The authors recently developed a cone-beam computed tomography (CT) scanner and this report presents their evaluation of its potential for thoracic vascular imaging. An X-ray tube and a video-fluoroscopic system were rotated around the objects and 360 projected images were collected in a 12-s scan. Each image was digitized and a 3 dimensional (D) image (256 x 256 x 256 voxel volume with a voxel dimension of 0.9 x 0.9 x 0.9 mm) was reconstructed. Two different 3D-CT angiographies were investigated in 2 pigs: right atriography and thoracic aortography. Each pig was anesthetized, mechanically ventilated and positioned within the scanner. Contrast agent was infused through the right atrium or the aortic root at a rate of 3 ml/s during the scan. The right atriography scan clearly delineated the anatomy of the pulmonary artery, heart chambers and thoracic aorta. The thoracic aortography scan also clearly delineated the aortic anatomy including the internal thoracic and intercostal arteries. In conclusion, cone-beam CT angiography is potentially useful for thoracic vascular imaging. (author)

  4. A Resonant Damping Study Using Piezoelectric Materials

    Science.gov (United States)

    Min, J. B.; Duffy, K. P.; Choi, B. B.; Morrison, C. R.; Jansen, R. H.; Provenza, A. J.

    2008-01-01

    Excessive vibration of turbomachinery blades causes high cycle fatigue (HCF) problems requiring damping treatments to mitigate vibration levels. Based on the technical challenges and requirements learned from previous turbomachinery blade research, a feasibility study of resonant damping control using shunted piezoelectric patches with passive and active control techniques has been conducted on cantilever beam specimens. Test results for the passive damping circuit show that the optimum resistive shunt circuit reduces the third bending resonant vibration by almost 50%, and the optimum inductive circuit reduces the vibration by 90%. In a separate test, active control reduced vibration by approximately 98%.

  5. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... of which shows a thin slice of the body. The images can then be studied from different angles by ... mail: Area code: Phone no: Thank you! ... Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain ...

  6. Impact of patient's age and disease duration on cardiac performance in acromegaly: a radionuclide angiography study.

    Science.gov (United States)

    Colao, A; Cuocolo, A; Marzullo, P; Nicolai, E; Ferone, D; Della Morte, A M; Petretta, M; Salvatore, M; Lombardi, G

    1999-05-01

    The aim of this study was to evaluate the impact of age and disease duration on cardiac performance in acromegaly. To address these issues, the left ventricular function at rest and during physical exercise was assessed by equilibrium radionuclide angiography in 40 rigorously selected patients with active acromegaly but without evidence of other complications able to affect heart function and in 32 healthy controls. Patients and controls were divided in two groups, on the basis of age below and above 40 yr. Circulating GH and insulin-like growth factor-I levels were significantly increased in patients, compared with controls, but were similar in the two groups of patients. At peak exercise, the systolic blood pressure was significantly higher in elderly patients (P 50%) in all but 2 patients and in all controls. The left ventricular ejection fraction at peak exercise was significantly decreased in elderly, compared with young, patients (P < 0.01) and in age-matched controls (P < 0.001). A normal response of the left ventricular ejection fraction to exercise was found in 12 of 40 patients (30%) and in 28 of 32 controls (87.5%) (chi2, 5.764; P < 0.01). Exercise-induced changes in left ventricular ejection fraction were significantly decreased in young (+5.2 +/- 4.4% vs. +21.3 +/- 3.4%, P < 0.005) and elderly patients (-10.2 +/- 2.8% vs. +13.7 +/- 2.7%, P < 0.0001), as compared with age-matched controls. The peak rate of left ventricular filling was significantly higher in young, than in elderly, patients whether peak filling rate was normalized to end-diastolic volume (P < 0.001), or stroke volume (P < 0.0001), or expressed as the ratio of peak filling rate to peak ejection rate (P < 0.001). The peak rate of left ventricular filling was significantly decreased in elderly patients, compared with young patients and age-matched controls, whether peak filling rate was normalized to end-diastolic volume (P < 0.01), or stroke volume (P < 0.005), or expressed as the ratio

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

    Science.gov (United States)

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

    2014-01-01

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

  8. High-resolution blood-pool-contrast-enhanced MR angiography in glioblastoma: tumor-associated neovascularization as a biomarker for patient survival. A preliminary study.

    Science.gov (United States)

    Puig, Josep; Blasco, Gerard; Daunis-I-Estadella, Josep; Alberich-Bayarri, Angel; Essig, Marco; Jain, Rajan; Remollo, Sebastián; Hernández, David; Puigdemont, Montserrat; Sánchez-González, Javier; Mateu, Gloria; Wintermark, Max; Pedraza, Salvador

    2016-01-01

    The objective of the study was to determine whether tumor-associated neovascularization on high-resolution gadofosveset-enhanced magnetic resonance angiography (MRA) is a useful biomarker for predicting survival in patients with newly diagnosed glioblastomas. Before treatment, 35 patients (25 men; mean age, 64 ± 14 years) with glioblastoma underwent MRI including first-pass dynamic susceptibility contrast (DSC) perfusion and post-contrast T1WI sequences with gadobutrol (0.1 mmol/kg) and, 48 h later, high-resolution MRA with gadofosveset (0.03 mmol/kg). Volumes of interest for contrast-enhancing lesion (CEL), non-CEL, and contralateral normal-appearing white matter were obtained, and DSC perfusion and DWI parameters were evaluated. Prognostic factors were assessed by Kaplan-Meier survival and Cox proportional hazards model. Eighteen (51.42 %) glioblastomas were hypervascular on high-resolution MRA. Hypervascular glioblastomas were associated with higher CEL volume and lower Karnofsky score. Median survival rates for patients with hypovascular and hypervascular glioblastomas treated with surgery, radiotherapy, and chemotherapy were 15 and 9.75 months, respectively (P contrast-enhanced MRA of newly diagnosed glioblastoma seems to be a useful biomarker that correlates with worse survival.

  9. Study on resonance frequency of thermoacoustic resonance pipes

    Institute of Scientific and Technical Information of China (English)

    FAN Li; WANG Benren; JIN Tao; ZHANG Shuyi

    2005-01-01

    For calculating the resonance frequency of practical resonance pipes more precisely, two methods are presented, which are the method of acoustic pressure simulation and the method of minimum point of standing wave. Both methods are based on the theoretical simulation of the acoustic pressure distribution in the pipe and the relation between the minimum point position of the standing wave and the acoustic impedances of the pipe terminations.It is demonstrated that both methods can calculate the resonance frequency of a pipe more precisely by considering the effect of the acoustic resistances of both terminations of the pipe.Therefore both methods presented are more useful in acoustic research fields in which the resonance frequency of a pipe must be controlled strictly. In addition, both methods can get the same calculation results despite of their different ways. The method of the minimum point of standing wave is more convenient, nevertheless the method of acoustic pressure simulation can derive the resonance frequency and the distribution of the acoustic pressure in the pipe simultaneously.

  10. Importance of oral fluid intake after coronary computed tomography angiography: An observational study

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Daiji [Department of Cardiology, Nagoya University Graduate School of Medicine (Japan); Department of Cardiology, Kami-iida Daiichi General Hospital, Nagoya (Japan); Isobe, Satoshi, E-mail: sisobe@med.nagoya-u.ac.jp [Department of Cardiology, Nagoya University Graduate School of Medicine (Japan); Department of Cardiology, Kami-iida Daiichi General Hospital, Nagoya (Japan); Sato, Kimihide; Ohashi, Toshio [Division of Radiology, Kami-iida Daiichi General Hospital, Nagoya (Japan); Fujiwara, Yuka; Ohyama, Hisato [Division of Nursing, Kami-iida Daiichi General Hospital, Nagoya (Japan); Ishii, Hideki; Murohara, Toyoaki [Department of Cardiology, Nagoya University Graduate School of Medicine (Japan)

    2011-01-15

    Background: The prevention of contrast-induced acute kidney injury (AKI) after coronary computed tomography angiography (CCTA) is important because patients referred for CCTA often need further contrast exposure such as an invasive coronary angiography. We aimed to examine the effects of oral volume intake on renal function in patients with preserved renal function referred for CCTA. Methods: We enrolled 180 patients who were referred for CCTA. The serum creatinine (SCr) and estimated glomerular filtration rate (eGFR) levels were measured before, 24 h, and a mean of 4.8 days after CCTA. The amount of unrestricted oral fluid intake for 24 h was checked. The patients were divided into two groups: 106 subjects with a rise in SCr after CCTA (group A); and 74 without (group B). Results: Significant correlations were observed between the amount of oral fluid intake and the percentage changes in SCr (%SCr) (r = -0.66, p < 0.0001) as well as the absolute changes in eGFR ({Delta}eGFR) (r = 0.65, p < 0.0001). The percentage of patients showing hemoglobin-A1c (HbA1c) {>=} 6.5% was greater in group A than in group B (29% vs. 18%, p < 0.001). Patients with HbA1c {>=} 6.5% showed higher %SCr and lower {Delta}eGFR compared to those without it. Multiple regression analysis revealed that the amount of oral fluid intake was the only independent predictor for a rise in SCr ({beta} = -0.731, p < 0.0001). Conclusion: Oral volume intake after CCTA is a very simple but important prophylactic procedure for contrast-induced AKI especially in diabetic patients.

  11. Collateral vessels in moyamoya disease : comparison of MR and MRA with conventional angiography

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Joo Eun; Yoon, Dae Young; Yi, Jeong Geun; Kim, Ho Chul; Choi, Chul Sun; Bae, Sang Hoon [Hallym University College of Medicine, Choonchun (Korea, Republic of)

    1998-01-01

    To determine the value of magnetic resonance imaging (MR) and magnetic resonance angiography (MRA) in assessing collateral vessels of moyamoya disease. Twenty-four patients with moyamoya disease who underwent MR, 3D TOF MRA, and conventional angiography participated in this study. Two radiologists working independently and with no knowledge of the angiographic findings, interpreted the MR and MRA images. To determine the presence of parenchymal and leptomeningeal collaterals (48 hemispheres) and transdural collaterals (38 hemispheres in 19 patients were depicted by angiography of the external carotid), the findings were compared with those of angiography. Parenchymal, leptomeningeal, and transdural collaterals were depicted by conventional angiography in 34 (71%), 32 (67%), and 11 (29%) hemispheres respectively. The sensitivity and specificity of MR/MRA for collateral vessels were 79.1/88.1 % for parenchymal collaterals, 72.1/88.1 % for leptomeningeal collaterals, and 0.1/18.1 % for transdural collaterals, respectively. Respective sensitivity and specificity of MR/MRA were 88.94/94.1% for leptomeningeal collaterals, and 18.93/55.1 % for transdural collaterals, when the prominent posterior cerebral and external carotid artery were regarded as secondary signs of leptomeningeal and transdural collateral vessels. In moyamoya disease, MR and MRA are useful imaging modalities for the assessment of collateral vessels. The prominent posterior cerebral artery and external carotid artery can be useful secondary signs of leptomeningeal and transdural collateral vessels. (author). 18 refs., 2 figs.

  12. Numerical and experimental studies of resonators with reduced resonant frequencies and small electrical sizes

    CERN Document Server

    Hao, T; Edwards, D J; Stevens, C J

    2008-01-01

    Methods on reducing resonant frequencies and electrical sizes of resonators are reported in this paper. Theoreti-cal and numerical analysis has been used and the results for the broadside-coupled resonators from both studies exhibit good agreement. Initial fabrication techniques are proposed and measurement results are compared with simulations. Further high resolution techniques have been envisaged to enhance the performance of the resona-tors. This class of small resonators with low resonant frequencies indicates a variety of applications in the design of microwave devices.

  13. Magnetic Resonance Materials in Physics, Biology and Medicine Fast Reduction of Undersampling Artifacts in Radial MR Angiography with 3D Total Variation on Graphics Hardware

    Science.gov (United States)

    Knoll, Florian; Unger, Markus; Diwoky, Clemens; Clason, Christian; Pock, Thomas; Stollberger, Rudolf

    2014-01-01

    Objective Subsampling of radially encoded MRI acquisitions in combination with sparsity promoting methods opened a door to significantly increased imaging speed, which is crucial for many important clinical applications. In particular, it has been shown recently that total variation (TV) regularization efficiently reduces undersampling artifacts. The drawback of the method is the long reconstruction time which makes it impossible to use in daily clinical practice, especially if the TV optimization problem has to be solved repeatedly to select a proper regularization parameter. Materials and Methods The goal of this work was to show that for the case of MR-Angiography, TV filtering can be performed as a post-processing step, in contrast to the common approach of integrating TV penalties in the image reconstruction process. With this approach it is possible to use TV algorithms with data fidelity terms in image space, which can be implemented very efficiently on graphic processing units (GPUs). The combination of a special radial sampling trajectory and a full 3D formulation of the TV minimization problem is crucial for the effectiveness of the artifact elimination process. Results and Conclusion The computation times of GPU-TV show that interactive elimination of undersampling artifacts is possible even for large volume data sets, in particular allowing the interactive determination of the regularization parameter. Results from phantom measurements and in vivo angiography data sets show that 3D TV, together with the proposed sampling trajectory, leads to pronounced improvements in image quality. However, while artifact removal was very efficient for angiography data sets in this work, it cannot be expected that the proposed method of TV post-processing will work for arbitrary types of scans. PMID:20352289

  14. Ferumoxytol as an off-label contrast agent in body 3T MR angiography: a pilot study in children

    Energy Technology Data Exchange (ETDEWEB)

    Ruangwattanapaisarn, Nichanan [Mahidol University, Department of Diagnostic and Therapeutic Radiology, Ramathibodi Hospital, Bangkok (Thailand); Stanford University, Department of Radiology, Stanford, CA (United States); Hsiao, Albert; Vasanawala, Shreyas S. [Stanford University, Department of Radiology, Stanford, CA (United States)

    2015-06-15

    Ferumoxytol is an ultrasmall superparamagnetic iron oxide (USPIO) nanoparticle agent used to treat iron deficiency anemia in adults with chronic kidney disease. We aim to determine the feasibility of using ferumoxytol for clinical pediatric cardiac and vascular imaging. We retrospectively identified 23 consecutive children who underwent MRI with ferumoxytol (11 males; mean age: 7.4 years, range: 3 days-18 years), yielding 12 abdominal MR angiography and 15 cardiac MRI studies. Medical records were reviewed for the clinical indication, ferumoxytol dose, injection rate, sedation and any complication. A two-reader consensus scored the images on a five-point scale for overall image quality and delineation of various anatomical structures. Signal-to-background ratios for abdominal aorta and inferior vena cava for abdominal cases and blood pool-myocardium contrast ratios for cardiac cases were calculated. The confidence intervals for obtaining a score of three or above for each image parameter were calculated by using adjusted Wald method. For abdominal MR angiography, average scores for overall image quality, as well as delineation of the hepatic artery, superior mesenteric artery, renal artery and veins were 4.5, 4.3, 4.3, 3.7 and 4.7, respectively. For cardiac exams, the average scores for overall image quality, systemic arteries, pulmonary arteries, pulmonary veins, valves and ventricles were 4.4, 4.6, 4.1, 4.8, 4.1 and 4.7, respectively. For all parameters, the lower bound for the proportion of cases to have a score of 3 or above was 65%. Signal-to-background ratios for aorta and abdominal veins averaged 86 +/- 74 and 86 +/- 77 for full-dose images, and 23 and 18 for half-dose images, respectively. Mean blood pool to myocardium contrast ratio was 3:3. Ferumoxytol can provide excellent image quality for pediatric body MR angiography/MR venography at a dose of 1.5 or 3 mg Fe/kg. Further investigation should be directed toward understanding the lowest dose that can be

  15. Diagnostic performance of combined noninvasive coronary angiography and myocardial perfusion imaging using 320 row detector computed tomography: design and implementation of the CORE320 multicenter, multinational diagnostic study.

    Science.gov (United States)

    Vavere, Andrea L; Simon, Gregory G; George, Richard T; Rochitte, Carlos E; Arai, Andrew E; Miller, Julie M; Di Carli, Marcello; Arbab-Zadeh, Armin; Zadeh, Armin A; Dewey, Marc; Niinuma, Hiroyuki; Laham, Roger; Rybicki, Frank J; Schuijf, Joanne D; Paul, Narinder; Hoe, John; Kuribyashi, Sachio; Sakuma, Hajime; Nomura, Cesar; Yaw, Tan Swee; Kofoed, Klaus F; Yoshioka, Kunihiro; Clouse, Melvin E; Brinker, Jeffrey; Cox, Christopher; Lima, Joao A C

    2011-01-01

    Multidetector coronary computed tomography angiography (CTA) is a promising modality for widespread clinical application because of its noninvasive nature and high diagnostic accuracy as found in previous studies using 64 to 320 simultaneous detector rows. It is, however, limited in its ability to detect myocardial ischemia. In this article, we describe the design of the CORE320 study ("Combined coronary atherosclerosis and myocardial perfusion evaluation using 320 detector row computed tomography"). This prospective, multicenter, multinational study is unique in that it is designed to assess the diagnostic performance of combined 320-row CTA and myocardial CT perfusion imaging (CTP) in comparison with the combination of invasive coronary angiography and single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI). The trial is being performed at 16 medical centers located in 8 countries worldwide. CT has the potential to assess both anatomy and physiology in a single imaging session. The co-primary aim of the CORE320 study is to define the per-patient diagnostic accuracy of the combination of coronary CTA and myocardial CTP to detect physiologically significant coronary artery disease compared with (1) the combination of conventional coronary angiography and SPECT-MPI and (2) conventional coronary angiography alone. If successful, the technology could revolutionize the management of patients with symptomatic CAD.

  16. Application study of 640-slice computed tomography low dose coronary angiography

    Directory of Open Access Journals (Sweden)

    Ziqiao Lei

    2015-01-01

    Full Text Available Objective: The aim was to explore image quality and radiation dose in patients with different heart rates in 640-slice volume computed tomography (CT coronary angiography by using tube voltage of 100 kV. Materials and Methods: The 220 consecutive patients clinically suspected or confirmed of coronary artery disease were divided into three groups: 67 cases in 1 beat group (heart rate 80 bpm. When scanning was completed, the best phase for coronary arteries would be chosen. Various postprocessing reconstructions of coronary arteries and branches, such as volume reconstruction (VR, maximum density projection, multiplanar reconstruction, curved surface reconstruction, were used. We classified image quality and made statistical analysis according to 4-grades method. We also compared scalability of coronary arterial segments and radiation doses between the groups. Results: There were no significant differences in the scalability of coronary arterial segments between the groups. Effective radiation doses of the three groups were (2.5±0.8 mSv, (8.4±3.1 mSv and (11.2±3.8mSv. The radiation doses between the groups showed statistical difference (P < 0.05. Conclusion: 640-slice volume CT can be adapted to changes during heart rate, and ensure the image quality under the condition of 100 kV, and radiation doses were significantly reduced in patients with heart rate <65 bpm.

  17. Diagnostic Performance of Self-navigated Whole-Heart Contrast-enhanced Coronary 3-T MR Angiography.

    Science.gov (United States)

    He, Yi; Pang, Jianing; Dai, Qinyi; Fan, Zhanming; An, Jing; Li, Debiao

    2016-11-01

    Purpose To evaluate the diagnostic performance of self-navigated whole-heart coronary 3-T magnetic resonance (MR) angiography by using conventional invasive coronary angiography (ICA) as the reference gold standard. Materials and Methods This study was approved by the local ethics committee. Written informed consent was obtained from each patient before the study. Thirty-nine consecutive patients underwent coronary MR angiography and later underwent ICA. Coronary MR angiography was performed with a 3-T imager with contrast agent enhancement during free breathing with self-navigated affine motion correction reconstruction. Coronary segments with reference diameters larger than 1.5 mm were included in the comparison between coronary MR angiography and ICA. The coronary MR angiography images were evaluated by two experienced readers blinded to the ICA results to identify significant luminal narrowing (>50% diameter reduction in reference ICA). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were performed to detect significant coronary artery stenosis. Results Coronary MR angiography examinations were successfully performed in all 39 patients. A total of 327 coronary segments had reference luminal diameter larger than 1.5 mm. Of these 327 coronary segments, 303 (92.7%) segments had a quality score greater than 1 at coronary MR angiography and were included in the analysis. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 78.2%, 75.0%, 81.8%, 70.6%, and 76.9%, respectively, on a per-patient basis. Conclusion Contrast-enhanced self-navigated coronary 3-T MR angiography is a promising technique for the noninvasive detection of clinically significant coronary stenosis. (©) RSNA, 2016.

  18. Periodontal disease, tooth loss and coronary heart disease assessed by coronary angiography: a cross-sectional observational study.

    Science.gov (United States)

    Zanella, S M; Pereira, S S; Barbisan, J N; Vieira, L; Saba-Chujfi, E; Haas, A N; Rösing, C K

    2016-04-01

    To evaluate the association between periodontal disease, tooth loss and coronary heart disease (CHD). There is still controversy about the relationship between periodontal disease and tooth loss with vessel obstruction assessed using coronary angiography. This cross-sectional study included 195 patients that underwent coronary angiography and presented with at least six teeth. Patients were classified into three categories of coronary obstruction severity: absence; one or more vessels with ≤ 50% obstruction; and one or more vessels with ≥ 50% obstruction. The extent of coronary obstruction was dichotomized into 0 and ≥ 1 affected vessels. A periodontist blinded to patient CHD status conducted a full mouth examination to determine mean clinical attachment loss, mean periodontal probing depth and tooth loss. Multiple logistic regression models were applied adjusting for age, gender, hypertension, smoking, body mass index, low-density lipoprotein cholesterol and C-reactive protein. Most patients were males (62.1%) older than 60 years (50.8%), and 61% of them had CHD. Mean periodontal probing depth, clinical attachment loss and tooth loss were 2.64 ± 0.72 mm, 4.40 ± 1.31 mm and 12.50 ± 6.98 teeth respectively. In the multivariable models, tooth loss was significantly associated with a higher chance of having at least one obstructed vessel (odds ratio = 1.04; 95% confidence interval 1.01-1.09) and with vessel obstruction ≥ 50% (odds ratio = 1.06; 95% confidence interval 1.01-1.11). No significant associations were found between periodontal variables and vessel obstruction. Tooth loss was found to be a risk indicator for CHD. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Ranking of magnetic resonance tomography of the infrarenal abdominal aorta aneurysms. Comparison with sonography, computed tomography, and angiography. Stellenwert der Kernspintomographie in der Diagnostik der infrarenalen Bauchaortenaneurysmen. Vergleich mit Sonographie, Computertomographie und Angiographie

    Energy Technology Data Exchange (ETDEWEB)

    Rieber, A.; Wrazidlo, W.; Brambs, H.J. (Heidelberg Univ. (Germany, F.R.). Radiologische Klinik); Allenberg, J.R. (Heidelberg Univ. (Germany, F.R.). Chirurgische Universitaetsklinik)

    15 patients with asymptomatic abdominal aortic aneurysms were evaluated with magnetic resonance imaging. The results were compared to the sonographic findings in 12, the computed tomographic in 14 and the angiographic findings in 14 cases. 14 patients were operated and the diagnostic results were verified. The advantage of MRI in comparison with the other diagnostic methods is the visualization of an infrarenal segment on the coronal images, which can be anastomized with the vascular prothesis. The evidence of this segment is important to know for the vascular surgeon to plan the operation technique. The disadvantage of MRI ist that thrombotic material and arterosclerotic plaques were bad or not visualized. We try to estimate, which importance the MRI will get in further times in the preoperative diagnosis of abdominal aortic aneurysms. (orig.).

  20. Membrane metamaterial resonators with a sharp resonance: A comprehensive study towards practical terahertz filters and sensors

    Directory of Open Access Journals (Sweden)

    Yongyao Chen

    2012-06-01

    Full Text Available We investigate the resonant properties of high quality-factor membrane-based metamaterial resonators functioning in the terahertz regime. A number of factors, including the resonator geometry, dielectric loss, and most importantly the membrane thickness are found to extensively influence the resonance strength and quality factor of the sharp resonance. Further studies on the membrane thickness-dependent-sensitivity for sensing applications reveal that high quality-factor membrane metamaterials with a moderate thickness ranging from 10 to 50 μm are the most promising option towards developing realistic integrated terahertz filters and sensors.

  1. Pilot study of dynamic cine CT angiography for the evaluation of abdominal aortic aneurysms : Implications for endograft treatment

    NARCIS (Netherlands)

    Teutelink, A; Rutten, A; Muhs, BE; Olree, M; van Herwaarden, JA; de Vos, AM; Prokop, M; Moll, FL; Verhagen, HJM

    Purpose: To utilize 40-slice electrocardiographically (ECG)-gated cine computed tomographic angiography (CTA) to characterize normal aortic motion during the cardiac cycle at relevant anatomical landmarks in preoperative abdominal aortic aneurysm (AAA) patients. Methods: In 10 consecutive

  2. Pilot study of dynamic cine CT angiography for the evaluation of abdominal aortic aneurysms : Implications for endograft treatment

    NARCIS (Netherlands)

    Teutelink, A; Rutten, A; Muhs, BE; Olree, M; van Herwaarden, JA; de Vos, AM; Prokop, M; Moll, FL; Verhagen, HJM

    2006-01-01

    Purpose: To utilize 40-slice electrocardiographically (ECG)-gated cine computed tomographic angiography (CTA) to characterize normal aortic motion during the cardiac cycle at relevant anatomical landmarks in preoperative abdominal aortic aneurysm (AAA) patients. Methods: In 10 consecutive preoperati

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

    Institute of Scientific and Technical Information of China (English)

    陈爽; 钱建国; 冯晓源

    2004-01-01

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

  4. Nuclear Quadrupole Resonance Study of Potassium - - Chloride.

    Science.gov (United States)

    Ramia, Maximo Elias

    Fast Fourier transform nuclear quadrupole resonance (NQR) was used to study the cubic antifluorite crystal potassium hexacloro-osmate, K(,2)OsCl(,6). The study of the ('35)Cl and ('37)Cl resonances were performed on three samples of K(,2)OsCl(,6), a powder sample, a powder sample recrystallized from D(,2)O and a single crystal sample. The studies were carried out in the temperature range 300 to 6K. A detailed study of the ('35)Cl and ('37)Cl NQR lineshapes, in the temperature range 70 to 300K, showed that the lineshapes reflect the strain fields produced by lattice dislocations and point defects. The temperature evolution of these strain fields give rise to a satellite line which previously was attributed to H('+) ion impurities present in the samples. A comprehensive study of the temperature evolution of the NQR spectrum in the vicinity of the phase transition revealed a drop of line intensity and the progressive appearance of an extra broad resonance component. Both effects are associated with the existence of precursor dynamic clusters at temperatures higher than T(,C). Qualitatively similar but quantitatively different behaviour was observed in the powder and single crystal samples. Although the precursor clusters are an intrinsic property of the phrase transition, their detailed dynamics is sample independent. A NQR study of the tetragonal phase showed that at the lowest temperature the ratio of line intensities is 2:1. The phase shift effect previously observed in the tetragonal phase of K(,2)ReCl(,6) was also observed in K(,2)OsCl(,6). The effect has been explained as an experimental artifact introduced by the truncation of the FID due to the spectrometer dead time. Spin-lattice relaxation measurements in the cubic phase show two component relaxation in the vicinity of T(,C). The behaviour is quantitatively different in the powder and single crystal samples. The short relaxation time is associated with dynamic clusters. Spin-lattice relaxation time

  5. Study on resonance frequency distribution of high-overtone bulk acoustic resonators

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui; WANG Zuoqing; ZHANG Shuyi

    2005-01-01

    Based on the method of characterizing piezo-films by the resonance frequency distributions, the factors influencing the resonance frequency distribution of a High-overtone Bulk Acoustic Resonator (HBAR) consisting of a piezoelectric thin film with twoelectrodes and a substrate are studied. Some HBARs are simulated. The results manifest that changing the acoustic impedance ratio of the substrate to piezo-film the distribution of the space of the parallel resonance frequency and the effective electromechanical coupling factor are changed. When the fundamental mode of the piezo-film is at high frequency, changing the acoustic impedance ratio of the electrode to piezo-film and the thickness of the electrodes make the resonance frequency distribution of HBARs change. These results manifest that the HBARs can be resonant at specified frequencies by means of adjusting the factors affecting the resonance frequency distribution.

  6. The blood flow in the posterior communicant artery. Angiographic study by using magnetic resonance

    CERN Document Server

    Portela, L A P

    1995-01-01

    did not change the direction of flow present, in the circumstances of this study. The arterial circle of Willis is the most important collateral pathway for the cerebral vessels when one the afferents is occluded. Its normal function, without vascular compromise, has been considered in conflicting ways in the literature. For centuries after its description by Thomas Willis in 1664 it was considered a flow equalizer, with free admixture of blood within it. Since the beginning of this century the dominant view is one of a potential value only, with null effective flow in the communicating arteries. The premise is included in different experimental models. Alternatively, it was considered that the normal direction of flow is antero-posterior, from carotid to posterior cerebral, since carotid flow is greater. Using phase-contrast magnetic resonance angiography, a non-invasive qualitative method, it was found in 40 patients without morphological brain abnormality and in 10 healthy volunteers that flow can be seen ...

  7. Follow-up of coiled intracranial aneurysms: comparison of 3D time-of-flight and contrast-enhanced magnetic resonance angiography at 3T in a large, prospective series

    Energy Technology Data Exchange (ETDEWEB)

    Pierot, Laurent [University of Reims, Department of Radiology, Maison Blanche Hospital, Reims (France); Hopital de la Maison Blanche - CHU, Service de radiologie, Reims (France); Portefaix, Christophe [University of Reims, Department of Radiology, Maison Blanche Hospital, Reims (France); University of Reims, CReSTIC SIC EA3804, Reims (France); Boulin, Anne [Foch Hospital, Department of Neuroradiology, Suresnes (France); Gauvrit, Jean-Yves [University of Rennes, Department of Radiology, CHU Rennes, Rennes (France)

    2012-10-15

    To compare 3D-TOF magnetic resonance angiography (MRA) and contrast-enhanced MRA (CE-MRA) sequences at 3T in the follow-up of coiled aneurysms with digital subtracted angiography (DSA) as the gold standard. DSA, 3D-TOF and CE-MRA were performed in a prospective series of 126 aneurysms in 96 patients (57 female, 39 male; age: 25-75 years, mean: 51.3 {+-} 11.3 years). The quality of aneurysm occlusion was assessed independently and anonymously by a core laboratory. Using DSA (gold standard technique), total occlusion was depicted in 57 aneurysms (45.2%), neck remnant in 34 aneurysms (27.0%) and aneurysm remnant in 35 aneurysms (27.8%). Sensitivity, specificity, positive predictive value and negative predictive value were very similar with 3D-TOF and CE-MRA. Visibility of coils was much better with 3D-TOF (95.2%) than with CE-MRA (23.0%) (P < 0.001). Also, substantial artefacts were less frequent with 3D-TOF (4.0%) than with CE-MRA (11.9%; P = 0.012). In this large prospective series of patients with coiled aneurysms, at 3T 3D-TOF MRA was equivalent to CE-MRA for the evaluation of aneurysm occlusion, but coil visibility was superior at 3D-TOF. Thus the use of 3D-TOF at 3T is recommended for the follow-up of coiled intracranial aneurysms. (orig.)

  8. TRICKS Magnetic Resonance Angiography at 3-Tesla for Assessing Whole Lower Extremity Vascular Tree in Patients with High-Grade Critical Limb Ischemia: DSA and TASC II Guidelines Correlations

    Directory of Open Access Journals (Sweden)

    Sheung-Fat Ko

    2012-01-01

    Full Text Available The entire vascular tree of 58 lower extremities with high-grade critical limb ischemia (CLI was assessed with three-station time resolved imaging of contrast kinetics (TRICKS magnetic resonance angiography (T-MRA and correlated with digital subtraction angiography (DSA examinations and Trans-Atlantic Inter-Society Consensus II (TASC II guidelines. Kappa (κ statistics were utilized to evaluate the agreement of stenosis scores (5-point scale; 0 normal to 4 occlusion based on T-MRA and DSA. With DSA as the standard, significant stenosis instances (stenosis score ≥2 among vascular segments were compared. The κ-statistics of image quality (4-point scale; 1 nondiagnostic to 4 excellent of T-MRA and TASC II classification assessed by a radiologist and a vascular surgeon were also evaluated. Among 870 vascular segments, excellent agreement was observed between T-MRA and DSA (mean κ = 0.883 in revealing stenosis (mean stenosis score, 2.1  ±  1.3 versus 2.0  ±  1.3. T-MRA harbored overall high sensitivity (99.5%, specificity (93.6%, positive predictive value (95.4%, negative predictive value (99.6%, and accuracy (97.7% in depicting significant stenosis. Excellent interobserver agreement (mean κ = 0.818 of superb image quality (mean score = 3.5–3.6 of T-MRA and outstanding agreement of TASC II classification of aortoiliac and femoral-popliteal lesions (κ = 0.912–0.917 between two raters further verified the clinical feasibility of T-MRA for treatment planning.

  9. Study of resonance in wind parks

    OpenAIRE

    Monjo, Lluis; Sainz, Luis; Liang, Jun; Pedra, Joaquín

    2015-01-01

    Wind turbine harmonic current emissions are a well-known power quality problem. These emissions flow through wind park impedances, leading to grid voltage distortion. Parallel resonance may worsen the problem because it increases voltage distortion around the resonance frequency. Hence, it is interesting to analyze the parallel resonance phenomenon. The paper explores this phenomenon in wind parks and provides analytical expressions to determine parallel resonances. (C) 2015 The Authors. Publ...

  10. Magnetic resonance spectroscopy studies in migraine

    Energy Technology Data Exchange (ETDEWEB)

    Montagna, P.; Cortelli, P.; Barbiroli, B. (Inst. of Medical Pathology, Univ. of Bologna (Italy))

    1994-06-01

    The authors describe the method of [sup 31]phosphorus magnetic resonance spectroscopy and review the results when it is applied to the study of brain and muscle energy metabolism in migraine subjects. Brain energy metabolism appears to be abnormal in all major subtypes of migraine when measured both during and between attacks. Impaired energy metabolism is also documented in skeletal muscle. It is suggested that migraine is associated with a generalized disorder of mitochondrial oxidative phosphorylation and that this may constitute a threshold for the triggering of migraine attacks. 47 refs., 10 figs., 3 tabs.

  11. Stochastic resonance and chaotic resonance in bimodal maps: A case study

    Indian Academy of Sciences (India)

    G Ambika; N V Sujatha; K P Harikrishnan

    2002-09-01

    We present the results of an extensive numerical study on the phenomenon of stochastic resonance in a bimodal cubic map. Both Gaussian random noise as well as deterministic chaos are used as input to drive the system between the basins. Our main result is that when two identical systems capable of stochastic resonance are coupled, the SNR of either system is enhanced at an optimum coupling strength. Our results may be relevant for the study of stochastic resonance in biological systems.

  12. High-resolution blood-pool-contrast-enhanced MR angiography in glioblastoma: tumor-associated neovascularization as a biomarker for patient survival. A preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Puig, Josep; Blasco, Gerard; Remollo, Sebastian; Hernandez, David; Pedraza, Salvador [Hospital Universitari Dr Josep Trueta, Research Unit of Diagnostic Imaging Institute (IDI), Department of Radiology [Girona Biomedical Research Institute] IDIBGI, Girona (Spain); Daunis-i-Estadella, Josep; Mateu, Gloria [University of Girona, Department of Computer Science, Applied Mathematics and Statistics, Girona (Spain); Alberich-Bayarri, Angel [La Fe Polytechnics and University Hospital, Biomedical Imaging Research Group (GIBI230), La Fe Health Research Institute, Valencia (Spain); Essig, Marco [University of Manitoba, Department of Radiology, Winnipeg (Canada); Jain, Rajan [NYU School of Medicine, Division of Neuroradiology, Department of Radiology, New York, NY (United States); Puigdemont, Montserrat [Hospital Universitari Dr Josep Trueta, Catalan Institute of Oncology (ICO), Hospital Cancer Registry, Girona (Spain); Sanchez-Gonzalez, Javier [Philips Healthcare Iberica, Madrid (Spain); Wintermark, Max [Stanford University, Department of Radiology, Neuroradiology Division, Palo Alto, CA (United States)

    2016-01-15

    The objective of the study was to determine whether tumor-associated neovascularization on high-resolution gadofosveset-enhanced magnetic resonance angiography (MRA) is a useful biomarker for predicting survival in patients with newly diagnosed glioblastomas. Before treatment, 35 patients (25 men; mean age, 64 ± 14 years) with glioblastoma underwent MRI including first-pass dynamic susceptibility contrast (DSC) perfusion and post-contrast T1WI sequences with gadobutrol (0.1 mmol/kg) and, 48 h later, high-resolution MRA with gadofosveset (0.03 mmol/kg). Volumes of interest for contrast-enhancing lesion (CEL), non-CEL, and contralateral normal-appearing white matter were obtained, and DSC perfusion and DWI parameters were evaluated. Prognostic factors were assessed by Kaplan-Meier survival and Cox proportional hazards model. Eighteen (51.42 %) glioblastomas were hypervascular on high-resolution MRA. Hypervascular glioblastomas were associated with higher CEL volume and lower Karnofsky score. Median survival rates for patients with hypovascular and hypervascular glioblastomas treated with surgery, radiotherapy, and chemotherapy were 15 and 9.75 months, respectively (P < 0.001). Tumor-associated neovascularization was the best predictor of survival at 5.25 months (AUC = 0.794, 81.2 % sensitivity, 77.8 % specificity, 76.5 % positive predictive value, 82.4 % negative predictive value) and yielded the highest hazard ratio (P < 0.001). Tumor-associated neovascularization detected on high-resolution blood-pool-contrast-enhanced MRA of newly diagnosed glioblastoma seems to be a useful biomarker that correlates with worse survival. (orig.)

  13. Noncontrast Computed Tomography versus Computed Tomography Angiography Source Images for Predicting Final Infarct Size in Anterior Circulation Acute Ischemic Stroke: a Prospective Cohort Study.

    Science.gov (United States)

    Mukherjee, Amritendu; Muthusami, Prakash; Mohimen, Aneesh; K, Srinivasan; B, Babunath; Pn, Sylaja; Kesavadas, Chandrasekharan

    2017-02-01

    There has been a recent debate regarding the superiority of computed tomography angiography source images (CTASIs) over noncontrast computed tomography (NCCT) to predict the final infarct size in acute ischemic stroke (AIS). We hypothesized that the parenchymal abnormality on CTASI in faster scanners would overestimate ischemic core. This prospective study assessed the correlation of Alberta Stroke Program Early CT Score (ASPECTS) on NCCT, CTASI, and computed tomography perfusion (CTP) with final infarct size in patients within 8 hours of AIS. Follow-up with NCCT or diffusion-weighted magnetic resonance imaging (MRI) was performed at 24 hours. Correlations of NCCT and CTASI with final infarct size and with CTP parameters were assessed. Subgroup analysis was performed in patients who underwent intravenous thrombolysis or mechanical thrombectomy. Inter-rater reliability was tested using Spearman's rank correlation. A P value less than .05 was considered statistically significant. A total of 105 patients were included in the final analysis. NCCT had a stronger correlation with the final infarct size than did CTASI (Spearman's ρ = .85 versus .78, P = .13). We found an overestimation of the final infarct size by CTASI in 47.6% of the cases, whereas NCCT underestimated infarct size in 60% of the patients. NCCT correlated most strongly with CBV (ρ = .93), whereas CTASI correlated most strongly with CBF (ρ = .87). Subgroup analysis showed less correlation of CTASI with final infarct size in the group that received thrombolysis versus the group that did not (ρ = .70 versus .88, P = .01). In a 256-slice scanner, the CTASI parenchymal abnormality includes ischemic penumbra and thus overestimates final infarct size-this could result in inappropriate exclusion of patients from thrombolysis or thrombectomy. Copyright © 2017 National Stroke Association. All rights reserved.

  14. The role of angiography in managing patients with temporal bone fractures: a retrospective study of 64 cases.

    Science.gov (United States)

    Ahmed, K Asif; Alison, David; Whatley, Wesley S; Chandra, Rakesh K

    2009-05-01

    We conducted a retrospective study of the utility of angiography in the evaluation of patients with temporal bone fractures. Our study population was made up of 64 patients-58 males and 6 females, aged 14 to 75 years (mean: 35.3)-with a temporal bone fracture who had presented to a level I trauma center over a 1-year period. Records were reviewed and data were obtained on the mechanism of injury; the type of fracture; associated injuries, particularly neurocranial injuries detected on computed tomography (CT) of the head; and any angiographic findings that might have been obtained. The primary outcomes measures were the type of treatment administered (conservative vs. surgical) and mortality. Patients were assigned to 1 of 4 groups according to CT results and angiographic findings, if any: normal CT and no angiogram (group 1; n = 12), abnormal CT and no angiogram (group 2; n = 28), abnormal CT and an abnormal angiogram (group 3; n = 9), and abnormal CT and a normal angiogram (group 4; n = 15). Conservative treatment was administered to all 12 patients in group 1 and to 9 patients (60%) in group 4; surgical treatment was provided to two-thirds of the patients in both group 2 and group 3. Mortality was low in group 1 (n = 0), group 3 (n = 1; 11%), and group 4 (n = 1; 7%), but high in group 2 (n = 10; 36%). In fact, the key finding of this study was that mortality in the group with an abnormal CT and no angiogram (group 2) was significantly higher than mortality in the group with an abnormal CT and an abnormal angiogram (group 3) (p = 0.02), even though the injuries in the 2 groups were similarly severe and their management was similarly aggressive. We conclude that current guidelines for angiography may need to be expanded to include all patients who have CT evidence of neurocranial injury in order to detect those vascular injuries that need aggressive management and thus lower overall mortality.

  15. [Gastric magnetic resonance study (methods, semiotics)].

    Science.gov (United States)

    Stashuk, G A

    2003-01-01

    The paper shows the potentialities of gastric study by magnetic resonance imaging (MRI). The methodic aspects of gastric study have been worked out. The MRI-semiotics of the unchanged and tumor-affected wall of the stomach and techniques in examining patients with gastric cancer of various sites are described. Using the developed procedure, MRI was performed in 199 patients, including 154 patients with gastric pathology and 45 control individuals who had no altered gastric wall. Great emphasis is placed on the role of MRI in the diagnosis of endophytic (diffuse) gastric cancer that is of priority value in its morphological structure. MRI was found to play a role in the diagnosis of the spread of a tumorous process both along the walls of the stomach and to its adjacent anatomic structures.

  16. Peripapillary retinal vessel density in eyes with acute primary angle closure: an optical coherence tomography angiography study.

    Science.gov (United States)

    Wang, Xiaolei; Jiang, Chunhui; Kong, Xiangmei; Yu, Xiaobo; Sun, Xinghuai

    2017-05-01

    The purpose was to investigate peripapillary retinal vessel density in resolved acute primary angle closure (APAC) eyes. This was a prospective, cross-sectional observational study. Thirty-four eyes of 34 patients with unilateral APAC were included, together with the fellow eyes with primary angle closure suspect (PACS) as controls. Peripapillary retinal vessel density was measured using optical coherence tomography (OCT) angiography. Peripapillary retinal vessel density was compared in both eyes and the potential relationship with visual field (VF) test results was evaluated. After an acute attack, the peripapillary retinal vessel density was lower in the APAC than in the PACS eyes (79.3 ± 8.2 versus 85.6 ± 4.9, respectively; P = 0.001). The VF mean deviation (MD) (-7.7 ± 6.7 versus -3.3 ± 1.8 dB, P = 0.002), and the pattern standard deviation (PSD) (4.6 ± 3.3 versus 2.4 ± 0.9 dB, P = 0.001) were worse for the APAC than the PACS eyes, but both had similar thicknesses of the retinal nerve fiber layer (RNFL) (111.8 ± 9.6 versus 114.1 ± 29.1 μm, P = 0.880) and ganglion cell complex (GCC) (94.7 ± 7.5 versus 91.8 ± 9.3 μm, P = 0.328). The peripapillary retinal vessel density was significantly correlated with the VF MD (vessel density: r = 0.455, P = 0.008) and PSD (vessel density: r = -0.592, P density, which was correlated with the VF values. OCT angiography is a reliable method for detecting vascular changes in glaucomatous eyes that show no thinning of the RNFL and GCC.

  17. Indocyanine green angiography findings in patients with long-standing Vogt-Koyanagi-Harada disease: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    da Silva Felipe T

    2012-08-01

    Full Text Available Abstract Background To investigate indocyanine green angiography (ICGA findings in patients with long-standing Vogt-Koyanagi-Harada (VKH disease and their correlation with disease activity on clinical examination as well as with systemic corticosteroid therapy. Methods Twenty-eight patients (51 eyes with long-standing (≥6 months from disease onset VKH disease whose treatment was tapered based only in clinical features were prospectively included at a single center in Brazil. All patients underwent standardized clinical evaluation, which included fundus photography, fluorescein angiography and ICGA. Clinical disease activity was determined based in the Standardization in Uveitis Nomenclature Working Group. Fisher exact test and logistic regression models were used for statistical analysis. Results Disease-related choroidal inflammation on ICGA was observed in 72.5% (31 of 51 eyes. Angiographic findings suggestive of (choroidal and/or retinal disease activity were not observed on FA. Clinically active disease based on clinical evaluation was observed in 41.2% (21 of 51 eyes. In these 21 eyes, disease-related choroidal inflammation on ICGA was observed in 76.2% (16 of 21 eyes; in the remaining eyes (without clinical active disease disease-related choroidal inflammation on ICGA was observed in 70.0% (21 of 30 eyes. In respect to systemic corticosteroid therapy, 10 patients (18 of 51 eyes were under treatment with prednisone. In these 10 (18 of 51 eyes patients, disease-related choroidal inflammation on ICGA was observed in 83.3% (15 of 18 eyes; in the remaining patients (33 of 51 eyes disease-related choroidal inflammation on ICGA was observed in 66.7% (22 of 33 eyes. Conclusion ICGA findings suggestive of disease-related choroidal inflammation were observed in a considerable proportion of patients with long-standing VKH disease, independent of the inflammatory status of the disease on clinical examination or current use of systemic

  18. Fast 3D coronary artery contrast-enhanced magnetic resonance angiography with magnetization transfer contrast, fat suppression and parallel imaging as applied on an anthropomorphic moving heart phantom

    NARCIS (Netherlands)

    Irwan, Roy; Russel, Inis K.; Sijens, Paul E.

    2006-01-01

    A magnetic resonance sequence for high-resolution imaging of coronary arteries in a very short acquisition time is presented. The technique is based on fast low-angle shot and uses fat saturation and magnetization transfer contrast Prepulses to improve image contrast. GeneRalized Autocalibrating Par

  19. Fast 3D coronary artery contrast-enhanced magnetic resonance angiography with magnetization transfer contrast, fat suppression and parallel imaging as applied on an anthropomorphic moving heart phantom

    NARCIS (Netherlands)

    Irwan, Roy; Russel, Inis K.; Sijens, Paul E.

    2006-01-01

    A magnetic resonance sequence for high-resolution imaging of coronary arteries in a very short acquisition time is presented. The technique is based on fast low-angle shot and uses fat saturation and magnetization transfer contrast Prepulses to improve image contrast. GeneRalized Autocalibrating Par

  20. Computed tomography coronary angiography in patients with acute myocardial infarction and normal invasive coronary angiography

    NARCIS (Netherlands)

    Panayi, Georgios; Wieringa, Wouter G.; Alfredsson, Joakim; Carlsson, Jorg; Karlsson, Jan-Erik; Persson, Anders; Engvall, Jan; Pundziute, Gabija; Swahn, Eva

    2016-01-01

    Background: Three to five percent of patients with acute myocardial infarction (AMI) have normal coronary arteries on invasive coronary angiography (ICA). The aim of this study was to assess the presence and characteristics of atherosclerotic plaques on computed tomography coronary angiography

  1. Transient cortical blindness after coronary angiography.

    Science.gov (United States)

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

    2009-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  3. Nuclear stress perfusion imaging versus computed tomography coronary angiography for identifying patients with obstructive coronary artery disease as defined by conventional angiography: insights from the CorE-64 multicenter study

    Directory of Open Access Journals (Sweden)

    Yutaka Tanami

    2014-08-01

    Full Text Available We investigated the diagnostic accuracy of computed tomography angiography (CTA versus myocardial perfusion imaging (MPI for detecting obstructive coronary artery disease (CAD as defined by conventional quantitative coronary angiography (QCA. Sixty-three patients who were enrolled in the CorE-64 multicenter study underwent CTA, MPI, and QCA imaging. All subjects were referred for cardiac catheterization with suspected or known coronary artery disease. The diagnostic accuracy of quantitative CTA and MPI for identifying patients with 50% or greater coronary arterial stenosis by QCA was evaluated using receiver operating characteristic (ROC analysis. Pre-defined subgroups were patients with known CAD and those with a calcium score of 400 or over. Diagnostic accuracy by ROC analysis revealed greater area under the curve (AUC for CTA than MPI for all 63 patients: 0.95 [95% confidence interval (CI: 0.89-0.100] vs 0.65 (95%CI: 0.53-0.77, respectively (P<0.01. Sensitivity, specificity, positive and negative predictive values were 0.93, 0.95, 0.97, 0.88, respectively, for CTA and 0.85, 0.45, 0.74, 0.63, respectively, for MPI. In 48 patients without known CAD, AUC was 0.96 for CTA and to 0.67 for SPECT (P<0.01. There was no significant difference in AUC for CTA in patients with calcium score below 400 versus over 400 (0.93 vs 0.95, but AUC was different for SPECT (0.61 vs 0.95; P<0.01. In a direct comparison, CTA is markedly superior to MPI for detecting obstructive coronary artery disease in patients. Even in subgroups traditionally more challenging for CTA, SPECT does not offer similarly good diagnostic accuracy. CTA may be considered the non-invasive test of choice if diagnosis of obstructive CAD is the purpose of imaging.

  4. Giant dipole resonance studied with GASP

    Energy Technology Data Exchange (ETDEWEB)

    Cinausero, M. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Bazzacco, D. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Bortignon, P.F. [Dipartimento di Fisica, I.N.F.N., Sezione di Milano, 20133, Milano (Italy); De Angelis, G. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Fabris, D. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Fiore, E.M. [Dipartimento di Fisica, I.N.F.N., Sezione di Bari, 70126, Bari (Italy); Fiore, L. [Dipartimento di Fisica, I.N.F.N., Sezione di Bari, 70126, Bari (Italy); Fioretto, E. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Fornal, B. [Institute of Nuclear Physics, 31342, Cracow (Poland); Gelli, N. [Dipartimento di Fisica, I.N.F.N., Sezione di Firenze, 50125, Firenze (Italy); Lops, M. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Lucarelli, F. [Dipartimento di Fisica, I.N.F.N., Sezione di Firenze, 50125, Firenze (Italy); Lunardi, S. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Nebbia, G. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Paticchio, V. [Dipartimento di Fisica, I.N.F.N., Sezione di Bari, 70126, Bari (Italy); Prete, G. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Rossi-Alvarez, C. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Viesti, G. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy)

    1996-03-18

    The giant dipole resonance (GDR) from the decay of excited {sup 156}Er nuclei populated in the reaction {sup 64}Ni+{sup 92}Zr at 241 MeV has been studied by using the GASP spectrometer. High-energy {gamma}-ray spectra have been obtained in coincidence with the 80 elements of the GASP inner ball and with discrete transitions in the residual nuclei {sup 155,154}Er. GDR parameters extracted from the high-energy {gamma}-ray spectra in coincidence with low-energy {gamma}-ray fold k>10 are in good agreement with systematics as well as with predictions from adiabatic calculations. No signature for entrance channel effects in the decay of {sup 156}Er was therefore observed from this lineshape analysis of the high-energy {gamma}-ray spectra in contrast with the case of the {sup 164}Yb nucleus. (orig.).

  5. Functional magnetic resonance imaging studies of language.

    Science.gov (United States)

    Small, Steven L; Burton, Martha W

    2002-11-01

    Functional neuroimaging of language builds on almost 150 years of study in neurology, psychology, linguistics, anatomy, and physiology. In recent years, there has been an explosion of research using functional imaging technology, especially positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), to understand the relationship between brain mechanisms and language processing. These methods combine high-resolution anatomic images with measures of language-specific brain activity to reveal neural correlates of language processing. This article reviews some of what has been learned about the neuroanatomy of language from these imaging techniques. We first discuss the normal case, organizing the presentation according to the levels of language, encompassing words (lexicon), sound structure (phonemes), and sentences (syntax and semantics). Next, we delve into some unusual language processing circumstances, including second languages and sign languages. Finally, we discuss abnormal language processing, including developmental and acquired dyslexia and aphasia.

  6. What Have We Learned from CONFIRM? Prognostic Implications from a Prospective Multicenter International Observational Cohort Study of Consecutive Patients Undergoing Coronary Computed Tomographic Angiography

    Science.gov (United States)

    Otaki, Yuka; Arsanjani, Reza; Gransar, Heidi; Cheng, Victor Y.; Dey, Damini; Labounty, Troy; Lin, Fay Y.; Achenbach, Stephan; Al-Mallah, Mouaz; Budoff, Matthew J.; Cademartiri, Filippo; Callister, Tracy Q.; Chang, Hyuk-Jae; Chinnaiyan, Kavitha; Chow, Benjamin J. W.; Delago, Augustin; Hadamitzky, Martin; Hausleiter, Joerg; Kaufmann, Philipp; Maffei, Erica; Raff, Gilbert; Shaw, Leslee J.; Villines, Todd C.; Dunning, Allison; Cury, Ricardo C.; Feuchtner, Gudrun; Kim, Yong-Jin; Leipsic, Jonathon; Berman, Daniel S.; Min, James K.

    2014-01-01

    Coronary computed tomographic angiography (CCTA) employing CT scanners of 64-detector rows or greater represents a novel noninvasive method for detection of coronary artery disease (CAD), providing excellent diagnostic information when compared to invasive angiography. In addition to its high diagnostic performance, prior studies have shown that CCTA can provide important prognostic information, although these prior studies have been generally limited to small cohorts at single centers. The Coronary CT Angiography EvaluatioN For clinical Outcomes: An InterRnational Multicenter Registry, or CONFIRM, is a large, prospective, multinational, dynamic observational cohort study of patients undergoing CCTA. This registry currently represents more than 32,000 consecutive adults suspected of having CAD who underwent ≥ 64–detector row CCTA at 12 centers in 6 countries between 2005 and 2009. Based on its large sample size and adequate statistical power, the data derived from CONFIRM registry has and will continue to provide key answers to many important topics regarding CCTA. Based on its multisite international national design, the results derived from CONFIRM should be considered as more generalizable than prior smaller single-center studies. This article summarizes the current status of several studies from CONFIRM registry. PMID:22689072

  7. Cerebral Circulation Time is Prolonged and Not Correlated with EDSS in Multiple Sclerosis Patients: A Study Using Digital Subtracted Angiography

    Science.gov (United States)

    Monti, Lucia; Donati, Donatella; Menci, Elisabetta; Cioni, Samuele; Bellini, Matteo; Grazzini, Irene; Leonini, Sara; Galluzzi, Paolo; Severi, Sauro; Burroni, Luca; Casasco, Alfredo; Morbidelli, Lucia; Santarnecchi, Emiliano; Piu, Pietro

    2015-01-01

    Literature has suggested that changes in brain flow circulation occur in patients with multiple sclerosis. In this study, digital subtraction angiography (DSA) was used to measure the absolute CCT value in MS patients and to correlate its value to age at disease onset and duration, and to expand disability status scale (EDSS). DSA assessment was performed on eighty MS patients and on a control group of forty-four age-matched patients. CCT in MS and control groups was calculated by analyzing the angiographic images. Lesion and brain volumes were calculated in a representative group of MS patients. Statistical correlations among CCT and disease duration, age at disease onset, lesion load, brain volumes and EDSS were considered. A significant difference between CCT in MS patients (mean = 4.9s; sd = 1.27s) and control group (mean = 2.8s; sd = 0.51s) was demonstrated. No significant statistical correlation was found between CCT and the other parameters in all MS patients. Significantly increased CCT value in MS patients suggests the presence of microvascular dysfunctions, which do not depend on clinical and MRI findings. Hemodynamic changes may not be exclusively the result of a late chronic inflammatory process. PMID:25679526

  8. Cerebral circulation time is prolonged and not correlated with EDSS in multiple sclerosis patients: a study using digital subtracted angiography.

    Directory of Open Access Journals (Sweden)

    Lucia Monti

    Full Text Available Literature has suggested that changes in brain flow circulation occur in patients with multiple sclerosis. In this study, digital subtraction angiography (DSA was used to measure the absolute CCT value in MS patients and to correlate its value to age at disease onset and duration, and to expand disability status scale (EDSS. DSA assessment was performed on eighty MS patients and on a control group of forty-four age-matched patients. CCT in MS and control groups was calculated by analyzing the angiographic images. Lesion and brain volumes were calculated in a representative group of MS patients. Statistical correlations among CCT and disease duration, age at disease onset, lesion load, brain volumes and EDSS were considered. A significant difference between CCT in MS patients (mean = 4.9s; sd = 1.27 s and control group (mean = 2.8s; sd = 0.51 s was demonstrated. No significant statistical correlation was found between CCT and the other parameters in all MS patients. Significantly increased CCT value in MS patients suggests the presence of microvascular dysfunctions, which do not depend on clinical and MRI findings. Hemodynamic changes may not be exclusively the result of a late chronic inflammatory process.

  9. Cerebral circulation time is prolonged and not correlated with EDSS in multiple sclerosis patients: a study using digital subtracted angiography.

    Science.gov (United States)

    Monti, Lucia; Donati, Donatella; Menci, Elisabetta; Cioni, Samuele; Bellini, Matteo; Grazzini, Irene; Leonini, Sara; Galluzzi, Paolo; Bracco, Sandra; Severi, Sauro; Burroni, Luca; Casasco, Alfredo; Morbidelli, Lucia; Santarnecchi, Emiliano; Piu, Pietro

    2015-01-01

    Literature has suggested that changes in brain flow circulation occur in patients with multiple sclerosis. In this study, digital subtraction angiography (DSA) was used to measure the absolute CCT value in MS patients and to correlate its value to age at disease onset and duration, and to expand disability status scale (EDSS). DSA assessment was performed on eighty MS patients and on a control group of forty-four age-matched patients. CCT in MS and control groups was calculated by analyzing the angiographic images. Lesion and brain volumes were calculated in a representative group of MS patients. Statistical correlations among CCT and disease duration, age at disease onset, lesion load, brain volumes and EDSS were considered. A significant difference between CCT in MS patients (mean = 4.9s; sd = 1.27 s) and control group (mean = 2.8s; sd = 0.51 s) was demonstrated. No significant statistical correlation was found between CCT and the other parameters in all MS patients. Significantly increased CCT value in MS patients suggests the presence of microvascular dysfunctions, which do not depend on clinical and MRI findings. Hemodynamic changes may not be exclusively the result of a late chronic inflammatory process.

  10. 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

  11. Simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) imaging: Comparison with contrast-enhanced MR angiography for measuring carotid stenosis.

    Science.gov (United States)

    Shu, Hongge; Sun, Jie; Hatsukami, Thomas S; Balu, Niranjan; Hippe, Daniel S; Liu, Haining; Kohler, Ted R; Zhu, Wenzhen; Yuan, Chun

    2017-02-06

    To evaluate in a proof-of-concept study the feasibility of Simultaneous Noncontrast Angiography and intraPlaque hemorrhage (SNAP) imaging as a clinical magnetic resonance angiography (MRA) technique for measuring carotid stenosis. There is a growing interest in detecting intraplaque hemorrhage (IPH) during the clinical management of carotid disease, yet luminal stenosis has remained indispensable during clinical decision-making. SNAP imaging has been proposed as a novel IPH imaging technique that provides carotid MRA with no added scan time. Flowing blood shows negative signal on SNAP because of phase-sensitive inversion recovery. In all, 58 asymptomatic subjects with 16-79% stenosis on ultrasound were scanned at 3T by SNAP with 0.8 mm isotropic resolution and 16 cm longitudinal coverage. Two readers measured luminal stenosis of bilateral carotid arteries (n = 116) on minimum intensity projections of SNAP using the NASCET criteria. In the subset (48 arteries) with contrast-enhanced (CE) MRA available for comparison, luminal stenosis was also measured on maximum intensity projections of CE-MRA. Intraclass correlation coefficients (ICCs) with 95% confidence intervals were 0.94 (0.90-0.96) and 0.93 (0.88-0.96) for intra- and interreader agreement on stenosis measurements, respectively. Corresponding kappas for grading stenosis (0-29%, 30-69%, 70-99%, and 100%) were 0.79 (0.67-0.89) and 0.80 (0.68-0.90). Agreement between SNAP and CE-MRA was high (ICC: 0.95 [0.90-0.98]; kappa: 0.82 [0.71-0.93]). As a dedicated IPH-imaging sequence, SNAP also provided carotid stenosis measurement that showed high intra- and interreader consistency and excellent agreement with CE-MRA. Further comparisons with digital subtraction angiography and other noninvasive techniques are warranted. 4 J. Magn. Reson. Imaging 2016. © 2017 International Society for Magnetic Resonance in Medicine.

  12. Can contrast-enhanced renal MR angiography replace conventional angiography in preoperative evaluation of living renal donors?

    Directory of Open Access Journals (Sweden)

    Abdelhady Taha Emam

    2011-01-01

    Full Text Available The aim of the study was to detect if gadolinium-enhanced renal magnetic reso-nance angiography (MRA can replace conventional angiography in imaging vascular anatomy in potential living renal donors and compare with surgical findings. MR imaging (MRI and breath-hold three-dimensional gadolinium-enhanced MRA of kidneys were done for 60 conse-cutive patients for whom successful nephrectomy was done. MRA findings were compared with the findings of nephrectomy. MRI and MRA identified 28 out of 60 patients with normal arterial and venous anatomy, and concordance was found at surgery in 27 of these patients. Vascular anomalies were depicted on MRI in 32 patients, with concordance at surgery in 27 patients. Re-garding arterial anomalies, the MRA had a sensitivity of 89.3%, a specificity of 94.0% and an accuracy of 90.8%. For venous anomalies, the sensitivity was 98.5%, specificity was 100% and accuracy was 98.6%. In conclusion, gadolinium-enhanced MRA of the kidneys can replace con-ventional angiography as a safe and accurate modality for the assessment of potential living renal donors.

  13. Peripheral moving-table contrast-enhanced magnetic resonance angiography (CE-MRA) using a prototype 18-channel peripheral vascular coil and scanning parameters optimized to the patient's individual hemodynamics.

    Science.gov (United States)

    Potthast, Silke; Wilson, Gregory J; Wang, Maisie S; Maki, Jeffrey H

    2009-05-01

    To demonstrate that with a priori determination of individual patient hemodynamics, peripheral contrast-enhanced magnetic resonance angiography (pCE-MRA) can be customized to maximize signal-to noise ratio (SNR) and avoid venous enhancement. Using a 1.5T MRI scanner and prototype 18-channel peripheral vascular (PV) coil designed for highly accelerated parallel imaging, geometry (g)-factor maps were determined. SNR-maximized protocols considering the two-dimensional sensitivity encoding (2D SENSE) factor, TE, TR, bandwidth (BW), and flip angle (FA) were precalculated and stored. For each exam, a small aortic timing bolus was performed, followed by dynamic three-dimensional (3D)-MRA of the calf. Using this information, the aorta to pedal artery and calf arteriovenous transit times were measured. This enabled estimation of the maximum upper and middle station acquisition duration to allow lower station acquisition to begin prior to venous arrival. The appropriately succinct SNR-optimized protocol for each station was selected and moving-table pCE-MRA was performed using thigh venous compression and high-relaxivity contrast material. The protocol was successfully applied in 15 patients and all imaging demonstrated good SNR without diagnosis-hindering venous enhancement. By knowing each patient's venous enhancement kinetics, scan parameters can be optimized to utilize maximum possible acquisition time. Some time is added for the timing scans, but in return time-resolved calf CE-MRA, maximized SNR, and decreased risk of venous enhancement are gained.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-05-15

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

  15. Occlusion of the circle of Willis. Diagnosis by 3D-time of flight MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Komatsumoto, Satoru; Ushioda, Takakazu; Nara, Masaharu [Ashikaga Red Cross Hospital, Tochigi (Japan)

    1996-08-01

    Magnetic resonance angiograms (MRA) were studied in 7 cases of occlusion of the circle of Willis. MRA successfully demonstrated the vascular obstructions and moyamoya vessels with a positive correlation to the angiographic findings. Leptomeningeal and transdural collateral vessels were also identified with MRA. As MRA is not invasive, it promises to become a valuable alternature to conventional angiography in the diagnosis of occlusion of the circle of Willis. (author)

  16. Comparison of the iron oxide-based blood-pool contrast medium VSOP-C184 with gadopentetate dimeglumine for first-pass magnetic resonance angiography of the aorta and renal arteries in pigs.

    Science.gov (United States)

    Schnorr, Jörg; Wagner, Susanne; Abramjuk, Claudia; Wojner, Ines; Schink, Tania; Kroencke, Thomas J; Schellenberger, Eyk; Hamm, Bernd; Pilgrimm, Herbert; Taupitz, Matthias

    2004-09-01

    VSOP-C184 at a dose of 0.045 mmol Fe/kg has been shown to be an efficient blood pool contrast medium for equilibrium magnetic resonance angiography (MRA) that can be administered as a bolus. The present study was performed to determine whether VSOP-C184 is also suitable for first-pass MRA. Fifteen MRA examinations at 1.5 T were performed in minipigs using a fast 3D fast low-angle shot (FLASH) sequence (repetition time = 4.5 ms, echo time = 1.7 ms, excitation angle = 25 degrees, matrix 256, body phased-array coil). The citrate-stabilized iron oxide preparation VSOP-C184 was investigated (total particle diameter: 7.0 +/- 0.15 nm; core size: 4 nm) and compared with gadopentetate dimeglumine (Gd-DTPA). The following doses were tested: VSOP-C184: 0.015, 0.025, and 0.035 mmol Fe/kg; Gd-DTPA: 0.1 and 0.2 mmol Gd/kg; n = 3 examinations/dose. Data were analyzed quantitatively (signal enhancement (ENH) and vessel edge definition (VED)) and qualitatively. First-pass MRA using the 3 doses of VSOP-C184 yielded the following ENH: aorta: 9.4 +/- 2.6; 12.31 +/- 1.2; 16.53 +/- 1.7; renal arteries: 7.6 +/- 2.2; 9.9 +/- 1.0; 13.2 +/- 0.5. The values for the 2 doses of Gd-DTPA were aorta: 12.9 +/- 1.0; 16.8 +/- 2.2; renal arteries: 11.2 +/- 1.23; 11.3 +/- 1.7. VED for the 3 doses of VSOP-C184 was aorta: 106.3 +/- 31.0; 135.3 +/- 58.8; 141.3 +/- 71.0; renal arteries: 102.2 +/- 24.3; 146.8 +/- 63.0; 126.9 +/- 37.6 and for the 2 doses of Gd-DTPA, aorta: 157.2 +/- 47.8; 164.2 +/- 36.8; renal arteries: 165.9 +/- 30.4; 170.3 +/- 38.2 respectively. The differences between VSOP-C184 and Gd-DTPA are clinically not relevant and statistically not significant (p > or = .05). Qualitative evaluation of image quality, contrast, and delineation of vessels showed the results obtained with VSOP-C184 at doses of 0.025 and 0.035 mmol Fe/kg to be similar to those of Gd-DTPA at 0.1 and 0.2 mmol Gd/kg. VSOP-C184 is suitable for first-pass MRA at doses of 0.025 and 0.035 mmol Fe/kg and thus, in addition to

  17. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain ...

  18. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... The teddy bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging (MRI) ...

  19. Cardiac risk factors and risk scores vs cardiac computed tomography angiography: a prospective cohort study for triage of ED patients with acute chest pain.

    Science.gov (United States)

    Halpern, Ethan J; Deutsch, Jacob P; Hannaway, Maria M; Estepa, Adrian T; Kenia, Anand S; Neuburger, Kenneth J; Levin, David C

    2013-10-01

    The objective of the study is to evaluate cardiac risk factors and risk scores for prediction of coronary artery disease (CAD) and adverse outcomes in an emergency department (ED) population judged to be at low to intermediate risk for acute coronary syndrome. Informed consent was obtained from consecutive ED patients who presented with chest pain and were evaluated with coronary computed tomography angiography (cCTA). Cardiac risk factors, clinical presentation, electrocardiogram, and laboratory studies were recorded; the Thrombolysis in Myocardial Infarction (TIMI) and Global Registry of Acute Coronary Events (GRACE) scores were tabulated. Coronary computed tomography angiography findings were rated on a 6-level plaque burden scale and classified for significant CAD (stenosis ≥50%). Adverse cardiovascular outcomes were recorded at 30 days. Among 250 patients evaluated by cCTA, 143 (57%) had no CAD, 64 (26%) demonstrated minimal plaque (70% stenosis). Six patients developed adverse cardiovascular outcomes. Among traditional cardiac risk factors, only age (older) and sex (male) were significant independent predictors of CAD. Correlation with CAD was poor for the TIMI (r = 0.12) and GRACE (r = 0.09-0.23) scores. The TIMI and GRACE scores were not useful to predict adverse outcomes. Coronary computed tomography angiography identified severe CAD in all subjects with adverse outcomes. Among ED patients who present with chest pain judged to be at low to intermediate risk for acute coronary syndrome, traditional risk factors are not useful to stratify risk for CAD and adverse outcomes. Coronary computed tomography angiography is an excellent predictor of CAD and outcome. © 2013.

  20. Study of spin resonances in the accelerators with snakes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.Y. (Brookhaven National Laboratory, Upton, NY 11973 (USA))

    1989-05-05

    Spin resonances in the circular accelerators with snakes are studied to understand the nature of snake resonances. We analyze the effect of snake configuration, and the snake superperiod on the resonance. Defining the {ital critical} {ital resonance} {ital strength} {epsilon}{sub {ital c}} as the maximum tolerable resonance strength without losing the beam polarization after passing through the resonance, we found that {epsilon}{sub {ital c}} is a sensitive function of the snake configuration, the snake superperiod at the first order snake resonance, the higher order snake resonance conditions and the spin matching condition. Under properly designed snake configuration, the critical resonance strength {epsilon}{sub {ital c}} is found to vary linearly with {ital N}{sub {ital S}} as {l angle}{epsilon}{sub {ital c}}{r angle}=(1/{pi})sin{sup {minus}1}(cos {pi}{nu}{sub z}{vert bar}{sup 1/2})N{sub S}, where {nu}{vert bar}{sub z} and N{sub S} are the betatron tune and the number of snakes respectively. We also study the effect of overlapping intrinsic and imperfection resonances. The imperfection resonance should be corrected to a magnitude of insignificance (e.g., {epsilon}{le}0.1 for two snakes case) to maintain proper polarization.

  1. Resonance Raman study of benzyl radical

    DEFF Research Database (Denmark)

    Langkilde, F.W.; Bajdor, K.; Wilbrandt, R.

    1992-01-01

    Time-resolved resonance Raman spectra are obtained of benzyl radicals created by laser flash photolysis of benzylchloride and diphenylacetone in solution. The spectra are obtained in resonance with the intense 2 2A2-1 B-2(2) transition of benzyl. The strong Raman bands are assigned to totally...... symmetric a1 modes. The remaining observed bands are tentatively assigned to fundamental modes of b1, a2, and b2 symmetry, and to overtones and combinations. The resonance Raman spectra are found to be quite different from previous fluorescence spectra of benzyl, and the origins of these differences...

  2. Intravascular ultrasound radiofrequency analysis after optimal coronary stenting with initial quantitative coronary angiography guidance: An ATHEROREMO sub-study

    NARCIS (Netherlands)

    G. Sarno (Giovanna); S.A. Garg (Scot); J. Gomez-Lara (Josep); H.M. Garcia-Garcia (Hector); J.M.R. Ligthart (Jürgen); N. Bruining (Nico); Y. Onuma (Yoshinobu); K. Witberg (Karen); R.J.M. van Geuns (Robert Jan); S.P.M. de Boer (Sanneke); J.J. Wykrzykowska (Joanna); C.J. Schultz (Carl); H.J. Duckers (Henricus); E.S. Regar (Eveline); P.P.T. de Jaegere (Peter); P.J. de Feyter (Pim); G.A. van Es (Gerrit Anne); H. Boersma (Eric); W.J. van der Giessen (Wim); P.W.J.C. Serruys (Patrick)

    2011-01-01

    textabstractAims: To investigate whether the use of intravascular ultrasound virtual histology (IVUS-VH) leads to any improvements in stent deployment, when performed in patients considered to have had an optimal percutaneous coronary intervention (PCI) by quantitative coronary angiography (QCA). Me

  3. Timing-Invariant CT Angiography Derived from CT Perfusion Imaging in Acute Stroke : A Diagnostic Performance Study

    NARCIS (Netherlands)

    Smith, E. J.; Vonken, E. -J.; Meijer, F. J. A.; Dankbaar, J. W.; Horsch, A. D.; van Ginneken, B.; Velthuis, B.; van der Schaaf, I.; Prokop, M.

    2015-01-01

    BACKGROUND AND PURPOSE: Timing-invariant (or delay-insensitive) CT angiography derived from CT perfusion data may obviate a separate cranial CTA in acute stroke, thus enhancing patient safety by reducing total examination time, radiation dose, and volume of contrast material. We assessed the diagnos

  4. CT-angiography source images indicate less fatal outcome despite coma of patients in the Basilar Artery International Cooperation Study

    NARCIS (Netherlands)

    Pallesen, Lars P.; Khomenko, Andrei; Dzialowski, Imanuel; Barlinn, Jessica; Barlinn, Kristian; Zerna, Charlotte; van der Hoeven, Erik J R J; Algra, Ale; Kapelle, L. Jaap; Michel, Patrik; Bodechtel, Ulf; Demchuk, Andrew M.; Schonewille, Wouter; Puetz, Volker

    2017-01-01

    Background: Coma is associated with poor outcome in patients with basilar artery occlusion. Aims: We sought to assess whether the posterior circulation Acute Stroke Prognosis Early CT Score and the Pons-Midbrain Index applied to CT angiography source images predict the outcome of comatose patients

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

    Directory of Open Access Journals (Sweden)

    Jelle T C Schrauwen

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

  6. Optimal scanning protocols of 64-slice CT angiography in coronary artery stents: An in vitro phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Almutairi, Abdulrahman Marzouq [Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University of Technology, Perth, Western Australia (Australia); Sun Zhonghua [Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University of Technology, Perth, Western Australia (Australia)], E-mail: z.sun@curtin.edu.au; Ng, Curtise [Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University of Technology, Perth, Western Australia (Australia); Al-Safran, Zakariya A.; Al-Mulla, Abeer A.; Al-Jamaan, Abdulaziz I. [Department of Medical Imaging, King Fahad Specialist Hospital, Dammam (Saudi Arabia)

    2010-04-15

    Purpose: The purpose of the study was to investigate the optimal scanning protocol of 64-slice CT angiography for assessment of coronary artery stents based on a phantom study. Materials and methods: Coronary stents with a diameter of 2.5 mm was implanted in thin plastic tubes with an inner diameter of 3.0 mm to simulate a coronary artery. The tubes were filled with iodinated contrast medium diluted to 178 HU, closed at both ends and positioned in a plastic container filled with vegetable oil (-70 to -100 HU). A series of scans were performed with a 64-slice CT scanner with the following protocols: section thickness: 0.67 mm, 1.0 mm, 1.5 mm, 2.0 mm, pitch value: 0.2, 0.3, 0.5 and reconstruction interval of 50% overlap of the section thickness. 2D axial and multiplanar reformatted images were generated to assess the visibility of stent lumen, while virtual intravascular endoscopy (VIE) was reconstructed to evaluate the artery wall and stent surface. Results: Our results showed that a scanning protocol of 1.0 mm slice thickness with a pitch of 0.3 produced acceptable images with best demonstration of the intrastent lumen and stent surface with minimal image noise or artifacts. In contrast, submillimeter scans with 0.67 mm resulted in moderate artifacts which affected visualization of the coronary lumen, in addition to the increased noise. When the section thickness increased to 1.5 mm and 2.0 mm, visualization of the artery wall and stent surface was compromised, although the intrastent lumen was still visible. Conclusion: Our in vitro study suggested that a scanning protocol of 1.0 mm section thickness with pitch of 0.3 is the optimal protocol for evaluation of coronary artery stents as it allows generation of acceptable images with better visualization of stent lumen, stent surface and coronary artery wall.

  7. A study of trapped mode resonances in asymmetric X-shape resonator for frequency selective surface

    Science.gov (United States)

    Chen, Kejian; Liu, Hong; Wang, Yiqi; Zhu, Yiming

    2013-08-01

    FSS is a two-dimensional periodic array of resonating metallic-dielectric structures, When FSS device steps into Terahertz range from microwave range, it is studied as THz functional components (such as Terahertz filter, Terahertz biochemical sensor, etc.) to promote the functionality of the THz spectroscopy/imaging system. When the device requires a narrow band transmission window for frequency selecting or a high electric field concentration in certain area to improve its sensitivity for sensing, normally, a high quality (Q) resonant structure can give helps. Recently, high-Q resonance induced by trapped mode resonance i studied widely in FSS research areas. To induce trapped mode resonance, one can simply break the symmetric of the unit structure of FSS. In this paper, several asymmetric X-shaped resonators for FSS working in terahertz range have been studied numerically. To compare the behaviour of X-shape resonator under different conditions (with additional part: Heart lines, Shoulder lines, Wrap or Shoes squares), a common platform (θ=60, θis angle of X shape) which is suitable for most of cases was used to make the study more meaningful. As the field enhancement behaviour is related to the trapped mode introduced by the asymmetric structure, we propose such kind of device to be used as a high quality filter or as a sensing element for biochemical samples.

  8. NUCLEAR MAGNETIC RESONANCE STUDIES OF URANOCENES

    Energy Technology Data Exchange (ETDEWEB)

    Luke, Wayne D.; Streitwieser, Jr., Andrew

    1979-12-01

    In the past several years a substantial amount of work has been devoted toward evaluation of the contact and pseudocontact contributions to the observed isotropic shifts in H nuclear magnetic resonance (NMR) spectra of uranium(IV) organometallic compounds. One reason for interest in this area arises from using the presence of contact shifts as a prcbe for covalent character in the uranium carbon bonds in these compounds. Several extensive {sup 1}H NNR studies on Cp{sub 3} U-X compounds and less extensive studies on uranocenes have been reported. Interpretation of these results suggests that contact shifts-contribute significantly to the observed isotropic shifts. Their presence has been taken as indicative of covalent character of metal carbon bonds in these systems, but agreement is not complete. In this paper we shall review critically the work reported on uranocenes in the light of recent results and report recent work on attempted separation of the observed isotropic shifts in alkyluranocenes into contact and pseudocontact components.

  9. The influence of cardiac function on coronary arterial enhancement at coronary computed tomography angiography: A cross-sectional study

    Directory of Open Access Journals (Sweden)

    Maryam Moradi

    2016-01-01

    Full Text Available Background: The purpose of this study was to evaluate the influence of ejection fraction (EF on peak aortic time (PAT and peak aortic enhancement (PAE during coronary computed tomography angiography (CTA. Materials and Methods: One-hundred and twenty patients (64 men, 56 women underwent measurement of coronary CTA with a measurement of EF within 3 months of coronary CTA. Pearson's correlation coefficient analysis was used to investigate the relationships between EF, PAT and PAE, and peak attenuation of all coronary arteries. Results: The range of EF was (25%–70% (mean: 55 ± 7.7. The range of PAT and PAE of ascending aorta on bolus test was 13–31 s (mean: 19.3 ± 2 and 153–435 HU (mean: 235 ± 40.6, respectively. Mean peak attenuation of ascending aorta, right coronary artery, left coronary artery, left circumflex artery, and left anterior descending were (561 ± 119, (476 ± 109, (505 ± 108, (467 ± 113, and (473 ± 104, respectively. There was a negative correlation between EF and PAT (r = −0.266, P = 0.003; however, there was no significant correlation between EF and PAE (r = −0.027, P = 0.767.In addition, there was no significant correlation between EF and the peak attenuation of coronary arteries. Conclusion: PAT was related to EF, but there was no relationship between PAE and EF. One of the explanation is that the left ventricular EF used for our study was assessed with echocardiography which is used roughly estimation of EF with interval of 5%–10% and may cause confounding results.

  10. Unenhanced MR Angiography of the Foot: Initial Experience of Using Flow-Sensitive Dephasing–prepared Steady-State Free Precession in Patients with Diabetes

    Science.gov (United States)

    Liu, Xin; Fan, Zhaoyang; Zhang, Na; Yang, Qi; Feng, Fei; Liu, Pengcheng; Li, Debiao

    2014-01-01

    Purpose To assess image quality and diagnostic performance of unenhanced magnetic resonance (MR) angiography with use of flow-sensitive dephasing (FSD)–prepared steady-state free precession (SSFP) of the foot arteries in patients with diabetes. Materials and Methods This prospective study was approved by institutional review board. Informed consent was obtained from all subjects. Thirty-two healthy volunteers and 38 diabetic patients who had been scheduled for lower-extremity contrast material–enhanced MR angiography were recruited to undergo unenhanced MR angiography with a 1.5-T MR unit. Image quality and diagnostic accuracy of unenhanced MR angiography in the detection of significant arterial stenosis (≥50%) were assessed by two independent reviewers. Contrast-enhanced MR angiography was used as the reference standard. The difference in the percentage of diagnostic arterial segments at unenhanced MR angiography between healthy volunteers and diabetic patients was evaluated with the McNemar test and generalized estimating equation for correlated data. Signal-to-noise ratio (SNR) and artery-to-muscle contrast-to-noise ratio (CNR) of pedal arteries were measured and compared between the two MR angiography techniques by using the paired t test. Results All subjects successfully underwent unenhanced MR angiography of the foot. Unenhanced MR angiography yielded a high percentage of diagnostic arterial segments in both healthy volunteers (303 of 320 segments, 95%) and patients (341 of 370 segments, 92%), and there was no difference in the percentage between the two populations (P = .195). In patients, the average SNR and CNR at unenhanced MR angiography were higher than those at contrast-enhanced MR angiography (SNR: 90.7 ± 38.1 vs 81.7 ± 34.7, respectively, P = .023; CNR: 85.2 ± 33.2 vs 76.6 ± 33.5, respectively, P = .013). The average sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of unenhanced MR angiography

  11. Unenhanced MR angiography of the foot: initial experience of using flow-sensitive dephasing-prepared steady-state free precession in patients with diabetes.

    Science.gov (United States)

    Liu, Xin; Fan, Zhaoyang; Zhang, Na; Yang, Qi; Feng, Fei; Liu, Pengcheng; Zheng, Hairong; Li, Debiao

    2014-09-01

    To assess image quality and diagnostic performance of unenhanced magnetic resonance (MR) angiography with use of flow-sensitive dephasing (FSD)-prepared steady-state free precession (SSFP) of the foot arteries in patients with diabetes. This prospective study was approved by institutional review board. Informed consent was obtained from all subjects. Thirty-two healthy volunteers and 38 diabetic patients who had been scheduled for lower-extremity contrast material-enhanced MR angiography were recruited to undergo unenhanced MR angiography with a 1.5-T MR unit. Image quality and diagnostic accuracy of unenhanced MR angiography in the detection of significant arterial stenosis (≥50%) were assessed by two independent reviewers. Contrast-enhanced MR angiography was used as the reference standard. The difference in the percentage of diagnostic arterial segments at unenhanced MR angiography between healthy volunteers and diabetic patients was evaluated with the McNemar test and generalized estimating equation for correlated data. Signal-to-noise ratio (SNR) and artery-to-muscle contrast-to-noise ratio (CNR) of pedal arteries were measured and compared between the two MR angiography techniques by using the paired t test. All subjects successfully underwent unenhanced MR angiography of the foot. Unenhanced MR angiography yielded a high percentage of diagnostic arterial segments in both healthy volunteers (303 of 320 segments, 95%) and patients (341 of 370 segments, 92%), and there was no difference in the percentage between the two populations (P = .195). In patients, the average SNR and CNR at unenhanced MR angiography were higher than those at contrast-enhanced MR angiography (SNR: 90.7 ± 38.1 vs 81.7 ± 34.7, respectively, P = .023; CNR: 85.2 ± 33.2 vs 76.6 ± 33.5, respectively, P = .013). The average sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of unenhanced MR angiography were 88% (35 of 40 segments), 93% (107 of

  12. Eigenvalue study of a chaotic resonator

    Energy Technology Data Exchange (ETDEWEB)

    Banova, Todorka [Technische Universitaet Darmstadt, Institut fuer Theorie Elektromagnetischer Felder (TEMF), Schlossgartenstrasse 8, D-64289 Darmstadt (Germany); Technische Universitaet Darmstadt, Graduate School of Computational Engineering, Dolivostrasse 15, D-64293 Darmstadt (Germany); Ackermann, Wolfgang; Weiland, Thomas [Technische Universitaet Darmstadt, Institut fuer Theorie Elektromagnetischer Felder (TEMF), Schlossgartenstrasse 8, D-64289 Darmstadt (Germany)

    2013-07-01

    The field of quantum chaos comprises the study of the manifestations of classical chaos in the properties of the corresponding quantum systems. Within this work, we compute the eigenfrequencies that are needed for the level spacing analysis of a microwave resonator with chaotic characteristics. The major challenges posed by our work are: first, the ability of the approaches to tackle the large scale eigenvalue problem and second, the capability to extract many, i.e. order of thousands, eigenfrequencies for the considered cavity. The first proposed approach for an accurate eigenfrequency extraction takes into consideration the evaluated electric field computations in time domain of a superconducting cavity and by means of signal-processing techniques extracts the eigenfrequencies. The second approach is based on the finite element method with curvilinear elements, which transforms the continuous eigenvalue problem to a discrete generalized eigenvalue problem. Afterwards, the Lanczos algorithm is used for the solution of the generalized eigenvalue problem. In the poster, a summary of the applied algorithms, as well as, critical implementation details together with the simulation results are provided.

  13. Numerical study of transient nonlinear harbor resonance

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    It is generally accepted that nonlinear wave-wave interactions play an important role in harbor resonance. Nevertheless it is not clear how waves take part in those interactions. The aim of this paper is to investigate those processes for a rectangular harbor at transient phases. Long-period oscillations excited by bichromatic waves are simulated by the Boussinesq model. The simulations start from calm conditions for the purpose of studying the response process. The internal wavemaker stops working after the oscillations have reached a quasi-steady state, and it is used to simulate the damp process. In order to analyze temporary features of wave-wave interactions in different states, the wavelet-based bispectrum is employed. The influence of the short wave frequencies on long-period oscillations is investigated, and reasons are tried to be given from nonlinear triad interactions between different wave components and the interaction of short waves and the bay entrance. Finally, the response time and the damp time are estimated by a simple method.

  14. Reconstruction of the limbal vasculature after limbal-conjunctival autograft transplantation in pterygium surgery: an angiography study.

    Science.gov (United States)

    Kim, Yong Joon; Yoo, Seung Hoon; Chung, Jin Kwon

    2014-11-18

    We evaluated the angiographic features of the affected limbus in patients with pterygia and assessed limbal reconstruction outcomes after limbal-conjunctival autograft (LCA) transplantation in terms of vascular remodeling. We studied prospectively 31 eyes of 31 patients who underwent pterygium excision and LCA transplantation; 28 eyes of 28 normal participants served as controls. Anterior segment indocyanine green angiography (ICGA) was performed for each participant preoperatively and at 1 week, and 1 and 3 months postoperatively. The perioperative angiographic features of the pterygium were compared to those in normal eyes. The structural changes of the marginal corneal vascular arcades (MCAs) and LCA were quantitatively assessed postoperatively in terms of vascular density and lacunarity. Deteriorated MCAs that extended beyond the pterygium head were observed in the pterygium group. The pterygium had a dual blood supply from the conjunctival and episcleral circulations. In terms of limbal reconstruction, the engorged reperfusion vessels arose from the adjacent episcleral vessels along the limbus at 1 week postoperatively. The reconstructed MCAs had begun to appear at 1 month postoperatively and became apparent 3 months postoperatively in 26 (83.9%) of 31 eyes of the pterygium group, resulting in a successful clinical outcome. Higher vascular density and lower lacunarity were measured in the limbus and the graft at 3 months than at 1 month (P < 0.001 for all), which indicated fine reorganization of the reconstructed vessels. The pterygium had a dual blood supply, and the remodeling of the affected limbus and LCA continued up to 3 months postoperatively. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  15. The AngiographiC Evaluation of the Everolimus-Eluting Stent in Chronic Total Occlusion (ACE-CTO) Study.

    Science.gov (United States)

    Kotsia, Anna; Navara, Rachita; Michael, Tesfaldet T; Sherbet, Daniel P; Roesle, Michele; Christopoulos, George; Rangan, Bavana V; Haagen, Donald; Garcia, Santiago; Maniu, Calin; Pershad, Ashish; Abdullah, Shuaib M; Hastings, Jeffrey L; Kumbhani, Dharam J; Luna, Michael; Addo, Tayo; Banerjee, Subhash; Brilakis, Emmanouil S

    2015-09-01

    There are limited data on outcomes after implantation of second-generation drug-eluting stents in coronary chronic total occlusions (CTOs). We aimed to evaluate the frequency of angiographic restenosis and clinical outcomes after implantation of the everolimus-eluting stent (EES) in coronary CTOs. One hundred patients undergoing successful CTO percutaneous coronary intervention using EES at our institution between 2009 and 2012 were enrolled. The primary study endpoint was binary in-segment restenosis at 8-month follow-up quantitative coronary angiography. Secondary endpoints included death, myocardial infarction, target-lesion and target-vessel revascularization, and symptom improvement. Mean age was 64 ± 7 years and 99% of the patients were men. The successful crossing technique was antegrade wiring in 51 patients, antegrade dissection/reentry in 24 patients, and retrograde in 25 patients. Binary angiographic restenosis occurred in 46% of the patients (95% confidence interval [CI], 35%-57%). The pattern of restenosis was focal, proliferative, and total occlusion in 19 lesions (46%), 14 lesions (34%), and 8 lesions (20%), respectively. At 12 months, the incidences of death, myocardial infarction, target-lesion revascularization, and target-vessel revascularization were 2%, 2%, 37%, and 39%, respectively. At 12 months, symptoms were improved, unchanged, or worse compared with baseline in 89 patients, 8 patients, and 1 patient, respectively (2 patients died before the 12-month follow-up). On multivariable analysis, smaller stent diameter was associated with higher risk for binary angiographic restenosis. High rates of angiographic restenosis and repeat revascularization were observed among patients receiving EES in coronary CTOs, but most had significant symptom improvement.

  16. Assessing a narrated white board animation as part of the consent process for intravenous fluorescein angiography: a randomized educational study.

    Science.gov (United States)

    Mednick, Zale; Irrcher, Isabella; Hopman, Wilma M; Sharma, Sanjay

    2016-12-01

    To determine if a narrated white board animation (nWBA) video as part of the consent process for intravenous fluorescein angiography (IVFA) improves patient comprehension compared with a standard consent process. Prospective, randomized study. Patients undergoing an initial IVFA investigation. Three groups of 26 patients (N = 78) naïve to the IVFA procedure were included. Groups 1 and 2 consisted of patients undergoing IVFA for diagnostic purposes. Group 1 received the IVFA information via standard physician-patient interaction to obtain standard consent. Group 2 received IVFA information by watching an nWBA explaining the purpose, method, and risks of the diagnostic test to obtain informed consent. Group 3 comprised patients who were not scheduled to undergo IVFA. This group was exposed to both the standard and nWBA consent. All groups completed a 6-question knowledge quiz to assess retained information and a survey to reflect on the consent experience. Participants receiving information via standard physician-patient interaction to obtain informed consent had a lower mean knowledge score (4.38 out of 6; 73%) than participants receiving the information to obtain consent via nWBA (5.04 out of 6, 84%; P = 0.023). Of participants receiving both forms of information (group 3) to obtain informed consent, 73% preferred the nWBA to the standard consent process. Participants receiving consent information for an IVFA diagnostic test via nWBA have better knowledge retention regarding the IVFA procedure and preferred this medium compared with participants receiving the standard physician-patient interaction for obtaining consent. Incorporation of multimedia into the informed consent process should be explored for other diagnostic tests. Copyright © 2016 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  17. Preoperative planning for endovascular aortic repair of abdominal aortic aneurysms: feasibility of nonenhanced MR angiography versus contrast-enhanced CT angiography.

    Science.gov (United States)

    Goshima, Satoshi; Kanematsu, Masayuki; Kondo, Hiroshi; Kawada, Hiroshi; Kojima, Toshihisa; Sakurai, Kota; Watanabe, Haruo; Shimabukuro, Katsuya; Matsuno, Yukihiro; Ishida, Narihiro; Takemura, Hirofumi; Bae, Kyongtae T

    2013-06-01

    To compare vascular measurements to determine stent types and configurations for abdominal endovascular aneurysm repair (EVAR) by comparing results of contrast material-enhanced computed tomographic (CT) angiography and nonenhanced magnetic resonance (MR) angiography. This prospective study was institutional review board approved, and all patients provided written informed consent. Fifty patients (45 men and five women; mean age, 76.0 years) admitted for elective abdominal EVAR underwent preoperative abdominal CT angiography (triplanar reformatted images; section thickness of 1-3 mm) and nonenhanced MR angiography (triplanar two-dimensional single-shot turbo field-echo images; section thickness of 6 mm). Two observers independently completed standard measurement and device selection forms for endovascular stent planning for CT and MR angiography. Pearson and intraclass correlation coefficients were calculated to evaluate intermodality and interobserver differences. No significant difference was found in aortic neck diameter (observer 1: CT, 18.5 mm; MR, 19.0 mm; P = .43) (observer 2: CT, 19.6 mm; MR, 19.3 mm; P = .59), aortic neck diameter 15 mm distal to the lowest renal artery (observer 1: CT, 19.2 mm; MR, 19.2 mm; P = .38) (observer 2: CT, 19.6 mm; MR, 19.6 mm; P = .91), aortic neck length (observer 1: CT, 43.6 mm; MR, 43.6 mm; P = .85) (observer 2: CT, 44.4 mm; MR, 44.0 mm; P = .93), or other key vascular measurements (P = .23-.99) for preoperative planning. These included aneurysm diameter, lowest renal artery to aortic bifurcation length, aortic bifurcation diameter, common iliac artery diameters, external iliac artery diameters, length between orifices of lower renal and internal iliac arteries, and iliac artery sealing length. CT and MR angiography measurements showed very strong correlation (r = 0.92-0.99). Intraclass correlation coefficients between observers ranged from 0.90 to 0.98. Stent types and configurations determined with CT measurements remained

  18. Comparison of dual-source CT angiography and MR angiography in preoperative evaluation of intra- and extracranial vessels: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Muehlenbruch, Georg; Das, Marco; Mahnken, Andreas Horst; Guenther, Rolf W. [RWTH Aachen University, Department of Diagnostic and Interventional Radiology, Aachen (Germany); Mommertz, Gottfried; Langer, Stefan [RWTH Aachen University, Department of Vascular Surgery, Aachen (Germany); Schaaf, Meike; Thron, A.; Krings, Timo [RWTH Aachen University, Department of Neuroradiology, Aachen (Germany); Wildberger, Joachim Ernst [University Hospital Maastricht, Department of Radiology, Maastricht (Netherlands)

    2010-02-15

    Besides the assessment of carotid artery stenosis, evaluation of the vascular anatomy and lesions within both the extra- and intracranial arteries is crucial for proper clinical evaluation, treatment choice and planning. The purpose of our study was to evaluate the potential of dual-source CTA and 3T-MRA. In 16 symptomatic CAS patients, contrast-enhanced DSCT and 3T-MRA examinations were performed. For DSCT a dual-energy protocol with a 64 x 0.6-mm collimation was applied. In 3T-MRA intracranial high-resolution unenhanced TOF and extracranial contrast-enhanced MRA were performed. All examinations were analyzed for relevant morphologic and pathologic features or anomalies, and a total of 624 vessel segments were scored. All examinations were of diagnostic image quality with good to excellent vessel visibility. Almost all intracranial arteries were significantly better visualized by MRA compared to CTA (five of six vessels, p < 0.05). DSCT however allowed for further morphological carotid stenosis description, especially with respect to calcification. Although MRA proved to be superior in visualization of smaller intracranial arteries, all pre-interventionally relevant information could be perceived from DSCT. DSCT and MRA may both be regarded as a reliable, fast, pre-interventional imaging investigation in patients with carotid artery stenosis. (orig.)

  19. Magnetic resonance imaging; Imagerie par resonance magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Fontanel, F. [Centre Hospitalier, 40 - Mont-de -Marsan (France); Clerc, T. [Centre Hospitalier Universitaire, 76 - Rouen (France); Theolier, S. [Hospice Civils de Lyon, 69 - Lyon (France); Verdenet, J. [Centre Hospitalier Universitaire, 25 - Besancon (France)

    1997-04-01

    The last improvements in nuclear magnetic resonance imaging are detailed here, society by society with an expose of their different devices. In the future the different technological evolutions will be on a faster acquisition, allowing to reduce the examination time, on the development of a more acute cardiac imaging, of a functional neuro-imaging and an interactive imaging for intervention. With the contrast products, staying a longer time in the vascular area, the angiography will find its place. Finally, the studies on magnetic fields should allow to increase the volume to examine. (N.C.).

  20. Study of acoustic resonance of cascades

    Science.gov (United States)

    Honjo, M.; Tominaga, T.

    Discrete sounds and vibrations from guide vanes due to acoustic resonance in the vane flow path, are experimentally investigated. Other causes of pure sounds in stationary vanes are considered, such as direct radiation from wake shedding vortices, bubble vortices or leading edges, and radial or axial modes of air columns. Two-dimensional cascade tests are performed under various conditions, and the data are compared with theoretical results of flat plate cascades. Three-dimensional ducted guide vane model tests are carried out to apply prototype guide vanes, and to confirm the resonance of the two-dimensional tests. Results show that frequency is more sensitive to chord length than pitch length, and the ratio of the fluctuation frequency to fluid sound velocity/pitch length is independent of the scale. Bubble vortices on concave surfaces or leading edges are not exciting sources; and under the limit of solidity, no exciting energy can generate acoustic resonance in correspondence to the mode.

  1. Preoperative detection and localization of accessory pudendal artery with contrast-enhanced MR angiography.

    Science.gov (United States)

    Whang, Shin Young; Sung, Deuk Jae; Lee, Seun Ah; Park, Beom Jin; Kim, Min Ju; Cho, Sung Bum; Kim, Yun Hwan; Cheon, Jun

    2012-03-01

    To evaluate the diagnostic performance of contrast material-enhanced magnetic resonance (MR) angiography for preoperative detection and localization of accessory pudendal arteries (APAs) in patients with prostate cancer. This prospective study was approved by the institutional review board, and informed consent was obtained. Between July 2007 and December 2010, 127 patients underwent contrast-enhanced MR angiography following prostate MR imaging at 3.0 T before robot-assisted laparoscopic radical prostatectomy (RALP). APAs were defined as any arteries located in the periprostatic region and anastomosed with the common penile artery or its branches; they were then subclassified into lateral and apical APAs. For detecting and localizing APAs, MR angiograms were evaluated prospectively by one reader and retrospectively by two independent blinded readers. Diagnostic performance was determined on a per-patient basis by using surgical findings as the reference standard. In addition, the origin of APAs identified at both surgery and contrast-enhanced MR angiography was determined by consensus of two retrospective readers. Interreader agreements were assessed by using k statistics. At surgery, 19 APAs (seven right apical, three left apical, four right lateral, and five left lateral) were detected in 16 patients, and 16 of these APAs were localized in 13 patients at preoperative contrast-enhanced MR angiography. Prospectively, sensitivity, specificity, and accuracy of contrast-enhanced MR angiography for the localization of APAs were 81.3%, 93.7%, and 92.1%, while retrospectively they were 87.5%, 91.9%, and 91.3% for reader 2 and 75.0%, 90.1%, and 88.2% for reader 3, respectively. Overall interreader agreement was substantial (k = 0.795). Nine and seven APAs originated from the obturator artery and the inferior vesical artery, respectively. Contrast-enhanced MR angiography can be used for the preoperative detection of APAs in patients with prostate cancer. © RSNA, 2012.

  2. Three-dimensional multiphase time-resolved low-dose contrast-enhanced magnetic resonance angiography using TWIST on a 32-channel coil at 3 T: a quantitative and qualitative comparison of a conventional gadolinium chelate with a high-relaxivity agent.

    Science.gov (United States)

    Giesel, Frederik L; Runge, Val; Kirchin, Miles; Mehndiratta, Amit; Gerigk, Lars; Corell, Body; von Gall, Carl; Kauczor, Hans-Ulrich; Essig, Marco

    2010-01-01

    To evaluate low-dose contrast-enhanced magnetic resonance angiography (CE-MRA) at high temporal and spatial resolution for imaging of abdominal vascular structures. Contrast-enhanced magnetic resonance angiography (TWIST [time-resolved angiography with interleaved stochastic trajectories]) was performed in 8 male New Zealand white rabbits at 3 T using a prototype 32-channel coil. Gadoteridol (Gd-HP-DO3A, ProHance; Bracco Imaging SpA, Milan, Italy) and the high-relaxivity agent gadobenate dimeglumine (Gd-BOPTA, MultiHance; Bracco Imaging SpA), each at a dose of 0.04 mmol/kg body weight, were used in an intraindividual comparison. Quantitative analysis of contrast-to-noise ratio (CNR) was performed in regions of interest placed in the aorta and the adjacent tissues. The image quality in the aorta, external iliac artery, and vena cava was categorized by 2 independent blinded readers from excellent (1) to poor (3). A significantly (P Qualitative rating showed the image quality to be excellent for gadobenate dimeglumine and adequate for gadoteridol. Time-resolved CE-MRA performed at 3 T with a 32-channel volume coil can be improved using the high-relaxivity agent gadobenate dimeglumine, which increases quality and quantity of vessel enhancement.

  3. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...... theoretical consciousness through historical narrative ‘in practice’, by discussing selected historical topics from Western cultural history, within the disciplines of history, literature, visual arts, musicology, archaeology, philosophy, and theology. The title Resonances indicates the overall perspective...

  4. Fast 3D coronary artery contrast-enhanced magnetic resonance angiography with magnetization transfer contrast, fat suppression and parallel imaging as applied on an anthropomorphic moving heart phantom.

    Science.gov (United States)

    Irwan, Roy; Rüssel, Iris K; Sijens, Paul E

    2006-09-01

    A magnetic resonance sequence for high-resolution imaging of coronary arteries in a very short acquisition time is presented. The technique is based on fast low-angle shot and uses fat saturation and magnetization transfer contrast prepulses to improve image contrast. GeneRalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) is implemented to shorten acquisition time. The sequence was tested on a moving anthropomorphic silicone heart phantom where the coronary arteries were filled with a gadolinium contrast agent solution, and imaging was performed at varying heart rates using GRAPPA. The clinical relevance of the phantom was validated by comparing the myocardial relaxation times of the phantom's homogeneous silicone cardiac wall to those of humans. Signal-to-noise ratio and contrast-to-noise ratio were higher when parallel imaging was used, possibly benefiting from the acquisition of one partition per heartbeat. Another advantage of parallel imaging for visualizing the coronary arteries is that the entire heart can be imaged within a few breath-holds.

  5. Evaluation of CT-angiography of lower limb arteries: a preliminary study; Interet de l'arterio-scanner dans le bilan des arteriopathies des membres inferieurs: etude preliminaire

    Energy Technology Data Exchange (ETDEWEB)

    Walter, F.; Leyder, B.; Fays, J.; Blum, A.; Roland, J. [Hopital Central, Service d' Imagerie Guilloz, 54 - Nancy (France); Bronner, J.F.; Lehalle, B. [Centre Hospitalier Universitaire Nancy-Brabois, 54 - Vandoeuvre-les-Nancy (France)

    2001-04-01

    The purpose of this study was to assess the feasibility of CT Angiography (CTA) with a single row of detectors and to compare it to digital subtraction angiography (DSA) in the evaluation of lower limb peripheral arterial disease. A total of 22 patients underwent 24 lower limb Helical CTA using a Somatom Plus 4A (Siemens) and 24 DSA using an Angiostar unit (Siemens). CT angiography was performed in one acquisition (collimation 3 mm/couch motion 9 mm/ interval 2 mm) with tube rotation time of 0.75 sec from the aortic bifurcation to the calf. DSA was performed after catheterization of a common femoral artery using the Seldinger technique. Arteries were classified in four categories (normal or stenosis <50%, stenosis >50%, occlusion, aneurysm). VRT images and axial source images were assessed by two independent radiologists whereas digital angiographies were read by a vascular radiologist. Global interobserver agreement was good (Kappa=0.71). The degree of agreement between CTA and DSA ranged from low to excellent (0.25 to 0.97) depending on the artery. Lower limb CT angiography is a promising non invasive technique. VRT allows quick evaluation. However, is not accurate enough to replace digital angiography. (authors)

  6. Surface Plasmon Resonance Studies on Molecular Imprinting

    Directory of Open Access Journals (Sweden)

    Baoping Lin

    2002-01-01

    Full Text Available The molecular imprinted polymer (MIP members were fabricated with the print molecule L-phenylalanine ethyl ester. The elution and adsorption procedures were investigated by surface plasmon resonance in situ. The changes of refractive angle during elution procedure suggest that the MIP is prepared on the base of the non-covalent interactions. This MIP member sensor can achieve enantioselective recognition.

  7. Resonance raman studies of phenylcyclopropane radical cations

    NARCIS (Netherlands)

    Godbout, J.T.; Zuilhof, H.; Heim, G.; Gould, I.R.; Goodman, J.L.; Dinnocenzo, J.P.; Myers Kelley, A.

    2000-01-01

    Resonance Raman spectra of the radical cations of phenylcyclopropane and trans-1-phenyl-2-methylcyclopropane are reported. A near-UV pump pulse excites a photosensitizer which oxidizes the species of interest, and a visible probe pulse delayed by 35 ns obtains the spectrum of the radical ion. The tr

  8. The emerging role of multidetector row CT angiography in the diagnosis of cervical arterial dissection: preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Elijovich, Lucas [NYU Medical Center, Department of Neurology, New York, NY (United States); Kazmi, Khuram [NYU Medical Center, Department of Neurology, New York, NY (United States); NYU Medical Center, Department of Radiology, New York, NY (United States); Gauvrit, Jean Y. [NYU Medical Center, Department of Radiology, New York, NY (United States); Hopital Salengro, Department of Neuroradiology, Lille (France); Law, Meng [NYU Medical Center, Department of Radiology, New York, NY (United States)

    2006-09-15

    Cervical artery dissection is an important cause of ischemic stroke, particularly in young patients. The diagnosis can be made with invasive catheter angiography or non-invasive imaging, either with MRI in conjunction with MR angiography (MRA) or CT angiography (CTA). Both modalities have been shown to have a high specificity and sensitivity. New developments such as multi-slice CTA (MSCTA) are emerging as an alternative methods for imaging the cervical and intracranial arteries. However, the contribution of modern MSCTA to carotid artery dissection has not been reported. We present a retrospective series of seven patients in whom both MSCTA and cervical axial T1 MRI and MRA were performed in the acute to subacute setting of internal carotid artery dissection. Carotid artery dissection was identified in all seven patients by MSCTA. The combination of MRI and MRA identified dissection in five of the seven patients. Additionally, a pseudoaneurysm was identified by MSCTA that was missed by MRI and MRA. Our findings confirm that MSCTA is a complementary technique in comparison to cervical axial T1 MRI and cervical MRA for diagnosing carotid artery dissection, and at times may provide additional information that can impact patient management. (orig.)

  9. Image Quality of the 3 Dimensional Phase-Contrast Technique in an Intracranial Magnetic Resonance Angiography with Artifacts Caused by Orthodontic Devices: A Comparison with 3 Dimensional Time-of-Flight Technique

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Seong Jin; Kim, Young Soo; Hong, Hyun Sook [Dept. of Radiology, Soonchunhyang University College of Medicine, Bucheon (Korea, Republic of); Kim, Dong Hun [Dept. of Radiology, Chosun University School of Medicine, Kwangju (Korea, Republic of)

    2011-07-15

    To evaluate the degree of image distortion caused by orthodontic devices during a intracranial magnetic resonance angiography (MRA), and to determine the effectiveness of the 3 dimensional phase-contrast (3D PC). Subjects were divided into group A (n = 20) wearing a home-made orthodontic device, and group B (n = 10) with an actual orthodontic device. A 3.0T MR scanner was used, applying 3D time-of-flight (TOF) and 3D PC. Two board-certified radiologists evaluated images independently based on a four point scale classifying segments of the circle of Willis. Magnetic susceptibility variations and contrast-to-noise ratio (CNR) on maximum intensity projection images were measured. In group A, scores of the 3D TOF and 3D PC were 2.84 {+-} 0.1 vs. 2.88 {+-} 0.1 (before) and 1.8 {+-} 0.4 vs 2.83 {+-} 0.1 (after wearing device), respectively. In group B, the scores of 3D TOF and 3D PC were 1.86 {+-} 0.43 and 2.81 {+-} 0.15 (p = 0.005), respectively. Magnetic susceptibility variations showed meaningful results after wearing the device (p = 0.0001). CNRs of the 3D PC before and after wearing device were 142.9 {+-} 6.6 vs. 140.8 {+-} 7.2 (p = 0.7507), respectively. In the 3D TOF, CNRs were 324.8 {+-} 25.4 vs. 466.3 {+-} 41.7 (p = 0.0001). The 3D PC may be a solution method for distorted images by magnetic susceptibility in the intracranial MRA compared with 3D TOF.

  10. Fokker-Planck Study of Tokamak Electron Cyclotron Resonance Heating

    Institute of Scientific and Technical Information of China (English)

    SHIBingren; LONGYongxing; DONGJiaqi; LIWenzhong; JIAOYiming; WANGAike

    2002-01-01

    In this study, we add a subroutine for describing the electron cyclotron resonant heating calculation to the Fokker-Planck code. By analyzing the wave-particle resonance condition in tokamak plasma and the fast motion of electrons along magnetic field lines, suitable quasi-linear diffusion coefficients are given.

  11. Use of a semi-automated cardiac segmentation tool improves reproducibility and speed of segmentation of contaminated right heart magnetic resonance angiography.

    Science.gov (United States)

    Tandon, Animesh; Byrne, Nicholas; Nieves Velasco Forte, Maria de Las; Zhang, Song; Dyer, Adrian K; Dillenbeck, Jeanne M; Greil, Gerald F; Hussain, Tarique

    2016-08-01

    Three-dimensional printing has an increasing number of clinical applications in pediatric cardiology. Time required for dataset segmentation and conversion to stereolithography (STL) format remains a significant limitation. We investigated the impact of semi-automated cardiovascular-specific segmentation software on time and reproducibility of segmentation. Magnetic resonance angiograms (MRAs) of 19 patients undergoing intervention for right ventricular outflow lesions were segmented to demonstrate the right heart. STLs were created by two independent clinicians using semi-automated cardiovascular segmentation (SAS) and traditional manual segmentation (MS). Time was recorded and geometric STL disagreement was determined (0 % = no disagreement, 100 % = complete disagreement). MRA datasets were categorized as clean when only right heart structures were present in the MRA, or contaminated when left heart structures were also present and required removal. Eighteen (seven clean and 11 contaminated) cases were successfully segmented with both methods. Time to STL for clean datasets was faster with MS than SAS [median 209 s (IQR 192-252) vs. 296 s (272-317), p = 0.018] while contaminated datasets were faster with SAS [455 s (384-561) vs. 866 s (310-1429), p = 0.033]. Interobserver STL geometric disagreement was significantly lower using SAS than MS overall (0.70 ± 1.15 % vs. 1.31 ± 1.52 %, p = 0.030), and for the contaminated subset (0.81 ± 1.08 % vs. 1.75 ± 1.57 %, p = 0.036). Most geometric disagreement occurred at areas where left heart contamination was removed. Semi-automated segmentation was faster and more reproducible for contaminated datasets, while MS was faster but equally reproducible for clean datasets. Semi-automated segmentation methods are preferable for contaminated datasets and continued refinement of these tools should be supported.

  12. Follow-up of true visceral artery aneurysm after coil embolization by three-dimensional contrast-enhanced MR angiography.

    Science.gov (United States)

    Koganemaru, Masamichi; Abe, Toshi; Nonoshita, Masaaki; Iwamoto, Ryoji; Kusumoto, Masashi; Kuhara, Asako; Kugiyama, Tomoko

    2014-01-01

    We aimed to evaluate the outcomes of coil embolization of true visceral artery aneurysms by three-dimensional contrast-enhanced magnetic resonance (MR) angiography. We used three-dimensional contrast-enhanced MR angiography, which included source images, to evaluate 23 patients (mean age, 60 years; range, 28-83 years) with true visceral artery aneurysms (splenic, n=15; hepatic, n=2; gastroduodenal, n=2; celiac, n=2; pancreaticoduodenal, n=1; gastroepiploic, n=1) who underwent coil embolization. Angiographic aneurysmal occlusion was revealed in all cases. Follow-up MR angiography was conducted with either a 1.5 or 3 Tesla system 3-25 months (mean, 18 months) after embolization. MR angiography was evaluated for aneurysmal occlusion, hemodynamic status, and complications. Complete aneurysmal occlusion was determined in 22 patients (96%) on follow-up MR angiography (mean follow-up period, 18 months). Neck recanalization, which was observed at nine and 20 months after embolization, was confirmed in one of eight patients (13%) using a neck preservation technique. In this patient, a small neck recanalization covered by a coil mass was demonstrated. The complete hemodynamic status after embolization was determined in 21 patients (91%); the visualization of several collateral vessels, such as short gastric arteries, after parent artery occlusion was poor compared with that seen on digital subtraction angiography in the remaining two patients (9%). An asymptomatic localized splenic infarction was confirmed in one patient (4%). Our study presents the follow-up results from three-dimensional contrast-enhanced MR angiography, which confirmed neck recanalization, the approximate hemodynamic status, and complications. This effective and less invasive method may be suitable for serial follow-up after coil embolization of true visceral aneurysms.

  13. Low-dose CT pulmonary angiography on a 15-year-old CT scanner: a feasibility study

    Directory of Open Access Journals (Sweden)

    Moritz Kaup

    2016-12-01

    Full Text Available Background Computed tomography (CT low-dose (LD imaging is used to lower radiation exposure, especially in vascular imaging; in current literature, this is mostly on latest generation high-end CT systems. Purpose To evaluate the effects of reduced tube current on objective and subjective image quality of a 15-year-old 16-slice CT system for pulmonary angiography (CTPA. Material and Methods CTPA scans from 60 prospectively randomized patients (28 men, 32 women were examined in this study on a 15-year-old 16-slice CT scanner system. Standard CT (SD settings were 100 kV and 150 mAs, LD settings were 100 kV and 50 mAs. Attenuation of the pulmonary trunk, various anatomic landmarks, and image noise were quantitatively measured; contrast-to-noise ratios (CNR and signal-to-noise ratios (SNR were calculated. Three independent blinded radiologists subjectively rated each image series using a 5-point grading scale. Results CT dose index (CTDI in the LD series was 66.46% lower compared to the SD settings (2.49 ± 0.55 mGy versus 7.42 ± 1.17 mGy. Attenuation of the pulmonary trunk showed similar results for both series (SD 409.55 ± 91.04 HU; LD 380.43 HU ± 93.11 HU; P = 0.768. Subjective image analysis showed no significant differences between SD and LD settings regarding the suitability for detection of central and peripheral PE (central SD/LD, 4.88; intra-class correlation coefficients [ICC], 0.894/4.83; ICC, 0.745; peripheral SD/LD, 4.70; ICC, 0.943/4.57; ICC, 0.919; all P > 0.4. Conclusion The LD protocol, on a 15-year-old CT scanner system without current high-end hardware or post-processing tools, led to a dose reduction of approximately 67% with similar subjective image quality and delineation of central and peripheral pulmonary arteries.

  14. Supraaortic arteries: contrast-enhanced MR angiography at 3.0 T--highly accelerated parallel acquisition for improved spatial resolution over an extended field of view.

    Science.gov (United States)

    Nael, Kambiz; Villablanca, J Pablo; Pope, Whitney B; McNamara, Thomas O; Laub, Gerhard; Finn, J Paul

    2007-02-01

    To prospectively use 3.0-T breath-hold high-spatial-resolution contrast material-enhanced magnetic resonance (MR) angiography with highly accelerated parallel acquisition to image the supraaortic arteries of patients suspected of having arterial occlusive disease. Institutional review board approval and written informed consent were obtained for this HIPAA-compliant study. Eighty patients (44 men, 36 women; age range, 44-90 years) underwent contrast-enhanced MR angiography of the head and neck at 3.0 T with an eight-channel neurovascular array coil. By applying a generalized autocalibrating partially parallel acquisition algorithm with an acceleration factor of four, high-spatial-resolution (0.7 x 0.7 x 0.9 mm = 0.44-mm(3) voxels) three-dimensional contrast-enhanced MR angiography was performed during a 20-second breath hold. Two neuroradiologists evaluated vascular image quality and arterial stenoses. Interobserver variability was tested with the kappa coefficient. Quantitation of stenosis at MR angiography was compared with that at digital subtraction angiography (DSA) (n = 13) and computed tomographic (CT) angiography (n = 12) with Spearman rank correlation coefficient (R(s)). Arterial stenoses were detected with contrast-enhanced MR angiography in 208 (reader 1) and 218 (reader 2) segments, with excellent interobserver agreement (kappa = 0.80). There was a significant correlation between contrast-enhanced MR angiography and CT angiography (R(s) = 0.95, reader 1; R(s) = 0.87, reader 2) and between contrast-enhanced MR angiography and DSA (R(s) = 0.94, reader 1; R(s) = 0.92, reader 2) for the degree of stenosis. Sensitivity and specificity of contrast-enhanced MR angiography for detection of arterial stenoses greater than 50% were 94% and 98% for reader 1 and 100% and 98% for reader 2, with DSA as the standard of reference. Vascular image quality was sufficient for diagnosis or excellent for 97% of arterial segments evaluated. By using highly accelerated parallel

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

    NARCIS (Netherlands)

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

    2015-01-01

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

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

    NARCIS (Netherlands)

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

    2015-01-01

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

  17. EVALUATION OF MACULAR ISCHEMIA IN EYES WITH CENTRAL RETINAL VEIN OCCLUSION: An Optical Coherence Tomography Angiography Study.

    Science.gov (United States)

    Ghashut, Rima; Muraoka, Yuki; Ooto, Sotaro; Iida, Yuto; Miwa, Yuko; Suzuma, Kiyoshi; Murakami, Tomoaki; Kadomoto, Shin; Tsujikawa, Akitaka; Yoshimura, Nagahisa

    2017-06-30

    To quantitatively assess macular perfusion status using optical coherence tomography angiography in eyes with aflibercept-treated central retinal vein occlusion and resolved macular edema and to investigate the impact of macular morphology and perfusion status on visual function. This prospective consecutive case series included 23 patients with central retinal vein occlusion. All patients received intravitreal aflibercept injections before analysis. Visual acuity, macular sensitivity, and the macular nonperfusion area (NPA) were evaluated in eyes without macular edema. The macular NPA was evaluated by optical coherence tomography angiography using 3 mm × 3 mm images of the macula. Foveal ellipsoid zone disruption was also analyzed. The superficial macular NPA measured 4.15 mm ± 0.71 mm (95% confidence interval 3.85-4.46), and the deep macular NPA measured 4.23 mm ± 0.97 mm (95% confidence interval 3.82-4.56). The logarithm of the minimum angle of resolution visual acuity was significantly associated with foveal ellipsoid zone disruption (P = 0.001), the superficial macular NPA (P = 0.015), and the deep macular NPA (P = 0.018). Macular sensitivity correlated negatively with logarithm of the minimum angle of resolution visual acuity (P = 0.007), the superficial macular NPA (P = 0.029), and the deep macular NPA (P = 0.040), but not with the foveal ellipsoid zone disruption (P = 0.435). Optical coherence tomography angiography is a novel technique that enables segmented evaluation of the macular perfusion status in eyes with central retinal vein occlusion and provides visual prognostic information. Enlargement of the macular NPA in the superficial and deep layers was significantly correlated with impaired visual acuity and with decreased macular sensitivity in patients with aflibercept-treated central retinal vein occlusion and resolved macular edema.

  18. Feasibility and accuracy of coronary imaging in elderly patients using the 64-row multi-detector computed tomography: a correlation study with conventional coronary angiography

    Institute of Scientific and Technical Information of China (English)

    Wei Ling CHAN; Kui Hian SIM; Chee Khoon LIEW; Sze Piaw CHIN; Tiong Kiam ONG; Seyfarth Tobias; Yean Yip FONG; Choon Kiat ANG; Houng Bang LIEW; Rapaee ANNUAR

    2006-01-01

    Background Elderly patients generally have higher occurrence of coronary calcification, increased heart rate and difficulty with prolonged breath-holding. The aim of our study was to investigate the feasibility and accuracy of using 64-row multi-detector computed tomography (MDCT) in the assessment of coronary artery stenoses in elderly patients. Methods One hundred and fifty two patients with suspected or known coronary artery disease were divided into 4 groups according to their age (Group A: 40-49 years,n=34; Group B: 50-59 years, n=57; Group C: 60-69 years, n=48; Group D: 70 years and above; n=13). Coronary CT angiography (CTA) using a 64-row MDCT was performed and the findings were compared with that of conventional coronary angiography (CCA).Using axial images, multi-planar reconstructions (MPR) and maximum intensity projections (MIP), coronary segments of lumen diameter = 1.5mm were analyzed for the presence of significant stenosis (= 50% ). Results Percentages of poor image quality from coronary CTA preventing reliable correlations with CCA were 21%, 14%, 19% and 62% in Groups A to D respectively. Patients in Group D had significantly higher calcium scores compared with the other groups (P<0.001). In patients where CTA images were of acceptable quality, percentages of accurate correlations with CCA were 89.8%, 93.4%, 86.6% and 78.0% for Groups A to D respectively.There were no significant difference in serum creatinine, heart rate and contrast volume between the 4 groups. Conclusions The 64-row MDCT coronary angiography was less accurate and feasible for patients aged 70 years or above due to heavy coronary calcification and inability to perform a satisfactory breath-hold. However, a high diagnostic accuracy with the MDCT is possible in patients aged less than 70 years.

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

    Directory of Open Access Journals (Sweden)

    Asghar Mesbahi

    2009-03-01

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

  20. MR angiography (MRA)

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-01

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

  1. Nonenhanced hybridized arterial spin labeled magnetic resonance angiography of the extracranial carotid arteries using a fast low angle shot readout at 3 Tesla

    National Research Council Canada - National Science Library

    Ioannis Koktzoglou; Matthew T Walker; Joel R Meyer; Ian G Murphy; Robert R Edelman

    2016-01-01

    ... (MRA) of the extracranial carotid arteries using a fast low angle shot (FLASH) readout at 3 Tesla. Methods In this retrospective, institutional review board-approved and HIPAA-compliant study, we evaluated the image quality...

  2. Noninvasive detection of vertebral artery stenosis: a comparison of contrast-enhanced MR angiography, CT angiography, and ultrasound.

    Science.gov (United States)

    Khan, Sofia; Rich, Philip; Clifton, Andrew; Markus, Hugh S

    2009-11-01

    Vertebral stenosis is associated with a high risk of recurrent stroke, but noninvasive imaging techniques to identify it have lacked sensitivity. Contrast-enhanced MR angiography and CT angiography have been recently developed and appear to have better sensitivity. However, no prospective studies have compared both of these techniques with ultrasound against the gold standard of intra-arterial angiography in the same group of patients. Forty-six patients were prospectively recruited in whom intra-arterial angiography was being performed. Contrast-enhanced MR angiography, CT angiography, and duplex ultrasound were also performed. Angiographic images were analyzed blinded to patient identity by 2 experienced neuroradiologists. Contrast-enhanced MR angiography had the highest sensitivity and specificity (Radiologist 1, 0.83 and 0.91, respectively; Radiologist 2, 0.89 and 0.87) for detecting >or=50% stenosis. CT angiography had good sensitivity (Radiologist 1, 0.68; Radiologist 2, 0.58) and excellent specificity (Radiologist 1, 0.92; Radiologist 2, 0.93), whereas duplex had low sensitivity (0.44) but excellent specificity (0.95). For vertebral origin stenosis >or=50%, sensitivities were similar for contrast-enhanced MR angiography (Radiologist 1, 0.91; Radiologist 2, 0.82) but relatively higher for CT angiography (Radiologist 1, 0.82; Radiologist 2, 0.82) and duplex (0.67). Contrast-enhanced MR angiography is the most sensitive noninvasive technique to detect vertebral artery stenosis and also has high specificity. CT angiography has good sensitivity and high specificity. In contrast, ultrasound has low sensitivity and will miss many vertebral stenoses.

  3. Anterior cerebral artery variations detected by MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, Akira; Nomiyama, Keita; Takase, Yukinori; Kudo, Sho [Saga Medical School, Department of Radiology, Saga (Japan)

    2006-09-15

    From anatomical and angiographic studies, it is well known that there are several variations of the anterior cerebral artery (ACA). However, ACA variations have rarely been studied by magnetic resonance (MR) angiography. The purpose of this study was to investigate not only the type, location, configuration, and incidence of ACA variations, but also coexisting arterial pathology such as aneurysms detected by cranial MR angiography. We retrospectively reviewed cranial MR angiography images of 891 patients at our institution. All images were obtained with one of two 1.5-T scanners using the three-dimensional time-of-flight technique. Maximum intensity projection (MIP) images in the horizontal rotation view were displayed stereoscopically. We reviewed these horizontal MIP images, inferosuperior MIP images, and source images, and identified variations of the ACA. We found 50 instances (5.6%) of unilateral A1 segment aplasia, 27 (3.0%) of three A2 segments, 18 (2.0%) of an unpaired A2 segment, and 11 (1.2%) fenestrations of the A1 and/or A2 segment. Seven anterior communicating artery (ACoA) aneurysms and one ACA territory embolic infarction were found among the 50 patients with unilateral A1 segment aplasia. One ACoA aneurysm and one pericallosal infarction were found in the 27 patients with three A2 segments. Two distal ACA aneurysms were detected among the 18 patients with an unpaired A2 segment. No associated aneurysm was seen at the fenestrations. Although the clinical significance of ACA variations is usually minor, an associated aneurysm is found relatively frequently. Thus, recognizing ACA variations during the interpretation of cranial MR angiograms is important. (orig.)

  4. Higher CHADS2 score is associated with impaired coronary flow reserve: A study using phase contrast cine magnetic resonance imaging.

    Science.gov (United States)

    Kirigaya, Hidekuni; Kato, Shingo; Gyotoku, Daiki; Yamada, Nao; Iinuma, Naoki; Kusakawa, Yuka; Iguchi, Kohei; Miki, Yuko; Nakachi, Tatsuya; Fukui, Kazuki; Iwasawa, Tae; Kimura, Kazuo

    2016-10-15

    The presence of coronary microvascular dysfunction (CMD) is an important prognostic marker for coronary artery disease (CAD) patients. The purpose of this study was to investigate whether the CHADS2 score is associated with CMD evaluated by magnetic resonance imaging (MRI). One hundred forty three patients with known or suspected CAD (mean age 70.3±9.5years) were enrolled. All patients did not have any significant coronary stenosis on X-ray coronary angiography (CAG) at the time of MRI acquisition. By using a 1.5T MRI scanner, breath-hold phase contrast cine MRI images of coronary sinus (CS) were obtained to assess the blood flow of CS both at rest and during adenosine triphosphate (ATP) infusion. Coronary flow reserve (CFR) was calculated as CS blood flow during ATP infusion divided by CS blood flow at rest. CMD was defined as CFRcine MRI. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. Estudo da circulação hepatomesentérica pela angiografia por ressonância magnética com gadolínio: comparação entre doses simples e dupla no estudo de pacientes esquistossomóticos Gadolinium-enhanced magnetic resonance angiography for hepatomesenteric vascular evaluation: single and double doses comparison in schistosomiasis patients

    Directory of Open Access Journals (Sweden)

    Rogério Pedreschi Caldana

    2006-08-01

    Full Text Available OBJETIVO: Determinar a freqüência de visualização dos segmentos da circulação hepatomesentérica pela angiografia por ressonância magnética (angio-RM com contraste e comparar o valor do método, utilizando-se duas diferentes dosagens de gadolínio (doses simples e dupla. MATERIAIS E MÉTODOS: Estudo prospectivo de 36 pacientes esquistossomóticos submetidos a angio-RM. Os exames foram realizados em equipamento de RM de 1,5 T, usando-se bobina de corpo e bomba injetora para a administração endovenosa do contraste. Foram utilizadas, de maneira randomizada, dose dupla do contraste paramagnético (0,2 mmol/kg de Gd-DTPA em 21 pacientes e dose simples (0,1 mmol/kg em outros 15 pacientes. Os exames foram interpretados por dois observadores em consenso, que classificaram o grau de visualização de 25 segmentos vasculares estabelecidos para análise, sem conhecimento da dose de gadolínio utilizada. RESULTADOS: Os segmentos vasculares proximais e de maior calibre foram as estruturas com melhor grau de visualização na maioria da amostra em estudo. O tronco celíaco, a artéria hepática comum, a artéria esplênica, a croça e terço médio da artéria mesentérica superior, a veia porta, a veia esplênica e a veia mesentérica superior apresentaram grau 2 de visualização em mais de 70% da amostra. Quanto à comparação das diferentes dosagens, não houve diferença significante (p OBJECTIVE: To evaluate the visibility of hepatomesenteric vascular segments by 3D gadolinium-enhanced magnetic resonance (MR angiography and to compare the method effectiveness between two different gadolinium doses (single and double doses. MATERIALS AND METHODS: A prospective study was performed with 36 schistosomiasis patients who were submitted to 3D contrast-enhanced MR angiography. Scans were performed in a high-field equipment (1.5 T, with body coil and power injector for intravenous contrast administration. Contrast double doses (Gd-DTPA 0.2 mmol/kg and

  6. Contrast-enhanced MR angiography of the supra-aortic vessels in 24 seconds: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Kollias, S.S.; Binkert, C.A.; Ruesch, S.; Valavanis, A. [Institute of Neuroradiology, University Hospital of Zurich, CH-8091 Zurich (Switzerland)

    1999-06-01

    A contrast-enhanced, gradient-echo 3D pulse sequence providing angiographic information in 24 s was tested in five healthy subjects and used prospectively in 21 patients for the investigation of the cervical arteries. Indications included suspected stenosis of the carotid (in 13), or vertebral arteries (in 1), carotid dissection (3), variants of the branches of the aortic arch (2) and extracranial carotid aneurysms (2). The results in all patients were compared with those of intra-arterial digital subtraction angiography (DSA). In patients with carotid stenosis, they were also compared with high-resolution 3D time-of-flight (TOF) MR angiography (MRA). Good quality MR angiograms of the neck vessels were obtained with the fast 3D sequence in 20 of the 21 patients. One claustrophobic patient was unable to co-operate. The degree of internal carotid artery (ICA) stenosis was graded correctly (compared to DSA) in 21 of 24 cases (87.5 %). Two mild stenoses were overestimated as moderate using the fast MR sequence and one high-grade stenosis was misdiagnosed as a complete occlusion. Carotid dissection was confirmed in one case and correctly excluded in two. Four extracranial ICA aneurysms in two patients, arterial variants and stenosis of the origin of the vertebral artery were correctly diagnosed using the contrast-enhanced MR angiogram. Three-dimensional TOF MRA was unsuccessful due to motion artefacts in half of the cases of ICA stenosis. (orig.) With 6 figs., 2 tabs., 20 refs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-08-15

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

  8. Resonance Raman studies of the purple membrane.

    Science.gov (United States)

    Aton, B; Doukas, A G; Callender, R H; Becher, B; Ebrey, T G

    1977-06-28

    The individual resonance Raman spectra of the PM568 and M412 forms of light-adapted purple membrane from Halobacterium halobium have been measured using the newly developed flow technique. For comparison purposes, the Raman spectra of the model chromophores, all-trans- and 13-cis retinal n-butylamine, both as protonated and unprotonated Schiff bases, have also been obtained. In agreement with previous work, the Raman data indicate that the retinal chromophore is linked to the purple membrane protein via a protonated. Schiff base in the case of the PM568 and an unprotonated Schiff base for the M412 form. The basic mechanism for color regulation in both forms appears to be electron delocalization. The spectral features of the two forms are different from each other and different from the model compound spectra.

  9. Electron Paramagnetic Resonance Study of Pr

    Energy Technology Data Exchange (ETDEWEB)

    Tezuka, Keitaro; Hinatsu, Yukio

    2001-01-01

    Electron paramagnetic resonance (EPR) spectra of tetravalent praseodymium ions doped in the cubic perovskite compound BaHfO{sub 3} have been measured at 4.2 K. A very large hyperfine interaction with the {sup 141}Pr nucleus was observed in the spectrum of Pr{sup 4+}/ BaHfO{sub 3}. The results were analyzed based on the weak field approximation, and the g value (|g|=0.619) and a hyperfine coupling constant (A=0.0589 cm{sup {minus}1}) were obtained. The measured g value is much smaller than |-10/7|, which indicates that the crystal field effect on the behavior of a 4f electron is large. These g and A values were compared with the EPR results for other f{sup 1} ions in an octahedral crystal field.

  10. Visceral adipose tissue, adiponectin levels and insulin resistance are related to atherosclerosis as assessed by whole-body magnetic resonance angiography in an elderly population.

    Science.gov (United States)

    Hansen, T; Ahlström, H; Söderberg, S; Hulthe, J; Wikström, J; Lind, L; Johansson, L

    2009-07-01

    The principal aim of this study was to determine whether the amount of visceral adipose tissue (VAT) is more related than subcutaneous adipose tissue (SAT) to atherosclerosis assessed by whole-body MRA (WBMRA). A further objective was to investigate whether traditional risk factors, inflammation, or adipokines could explain the hypothesized relationship between VAT and atherosclerosis. Men and women aged 70 were recruited from the general population into the Prospective Investigation of The Vasculature in Uppsala Seniors (PIVUS) and 306 of them underwent WBMRA in a clinical 1.5-T scanner. The arterial tree was assessed for degree of stenosis or occlusion and a total atherosclerotic score (TAS) was established. Information on risk factors and BMI and on SAT and VAT, segmented on an axial MR scan was collected. Adiponectin, leptin, and high sensitive C-reactive protein (hsCRP) were measured in serum. HOMA index was used as a marker of insulin resistance. VAT was related to TAS independently of gender, total obesity (BMI), amount of SAT, hsCRP and also to the traditional risk factors included in the Framingham risk score (FRS) in an elderly population. Adiponectin or the HOMA insulin resistance, but not leptin or VAT, together with FRS was significantly related to TAS in a multiple censored regression model. Adiponectin attenuated the relationship between VAT and TAS, suggesting that adiponectin and insulin resistance is an important link between visceral adiposity and atherosclerosis.

  11. Risk factors for cervical carotid and intracranial cerebrovascular lesions in patients undergoing coronary artery bypass grafting. Preoperative evaluation using magnetic resonance imaging and angiography

    Energy Technology Data Exchange (ETDEWEB)

    Makino, Masahiro [Kyoto Prefectural Univ. of Medicine (Japan). Research Inst. for Neurological Diseases and Geriatrics

    2001-12-01

    Recently neurologic complications after coronary artery bypass grafting (CABG) have received increasing attention. There is no detailed report about the risk factors for these complications, although stenosis in the cervical and intracranial arteries, especially in Japanese patients, latent ischemic brain lesions and preoperative neurological conditions are related to these events. In this prospective study, we evaluated occlusive lesions in the cervical carotid and intracranial arteries, silent brain infarction and cerebral deep white matter lesion with MRA and MRI in patients scheduled to undergo CABG to determine the prevalence of occlusive diseases in cervical carotid and intracranial arteries, latent ischemic change in the brain in this population and to identify preoperative risk factors for these patients. The subjects were 144 consecutive patients (103 men and 41 women, mean age 65.9{+-}9.2 years old) who were scheduled for CABG under elective conditions and who were examined by the same MRI apparatus using the same protocol between November 1998 and March 2001. After routine neurological examination and Mini-Mental State Examination (MMSE) were completed, MRI and MRA were obtained, then the prevalence of abnormalities on MRI and MRA studies and risk factors were evaluated. Cervical carotid artery stenosis with {>=}50% luminal narrowing was detected in 29.2% of the subjects, and that with {>=}75% luminal narrowing was detected in 16.0% of the subjects. Intracranial arterial stenosis showing {>=}50% luminal narrowing was detected in 38.2% of subjects, and that showing {>=}75% luminal narrowing was detected in 19.4% of subjects. Brain infarction was observed in 74.3% of subjects, cerebral deep white matter lesion showing grade 2 or higher on Fazekas classification was observed in 17.4% of the subjects. The characteristics, including possible risk factors of subjects with and without these abnormal findings, were compared. Patients with cervical carotid

  12. [Study of Fermi resonance by means of solution concentration variation].

    Science.gov (United States)

    Jiang, Xiu-lan; Li, Dong-fei; Chen, Yuan-zheng; Zhou, Mi; Sun, Cheng-lin; Yang, Guang; Li, Zuo-wei; Gao, Shu-qin

    2011-05-01

    The values of Raman scattering coefficients of some molecules in which Fermi resonance occurs vary with solution concentration variation. We measured the Raman spectra of some solvents such as CCl4, CS2, C6H6, etc by changing the concentration of the solutions ranging from 10% to 100% in volume. As a result, the authors obtained the general law of Fermi resonance. We found some weak Fermi resonance phenomena as well that the two bands of Raman spectrum shift asymmetrically and that the fundamental of overtone is tuned by Fermi resonance and moves towards the same direction with the overtone simultaneously, which is same as the results Bier K. D. obtained by means of high-pressure technique. By means of this method, the authors demonstrated the conclusion that only the fundamental in combinations which has the same symmetry as the fundamental involved in Fermi resonance directly can its intensity variation influence the Fermi resonance. In this article, the authors present a new method to study Fermi resonance. This method is valuable in the identification and the assignment of spectral lines of solutions, the determination of molecular configuration of enzyme, the discrimination of isomer, as well as the influences on the molecular structures and properties caused by hydrogen bond.

  13. 3.0T非对比剂肝门静脉磁共振血管成像技术研究%Non-contrast-enhanced Magnetic Resonance Angiography of the Hepatic Portal Vein at 3.0 Tesla

    Institute of Scientific and Technical Information of China (English)

    姚斐斐; 程敬亮; 杨子涛; 李莹; 鲁果果

    2013-01-01

    Purpose To explore the methods of selectively visualizing hepatic portal vein by using three-dimensional fast imaging employing steady state acquisition combined with in-flow inversion recovery labeling pulse at 3.0 Tesla. Materials and Methods Ten healthy volunteers were examined under different TI (1200, 1400, 1600, 1800 ms), and the vessel-to-liver contrast ratio of the main portal vein, right portal vein, and left portal vein were measured. Results Non-contrast-enhanced MRA images of portal vein were obtained successfully in all ten volunteers. The signal intensity of peripheral portal branches gradually increased when TI increased from 1200 ms to 1600 ms, and the highest vessel-to-liver contrast ratio occurred when TI was 1400 ms. Conclusion Non-contrast enhanced magnetic resonance angiography of the hepatic portal vein can be successfully achieved at 3.0T high field MRI. A fixed TI of 1400 ms is preferable.%目的:在3.0T高场强MR成像仪上,探讨流入反转恢复标记脉冲带与三维稳态采集快速成像序列相结合选择性地显示肝脏门静脉的方法,并对扫描参数进行优化。资料与方法对10名健康志愿者分别进行反转时间(TI)为1200、1400、1600、1800 ms扫描,比较不同TI下肝脏门静脉主干、左支、右支与肝实质的相对信号强度。结果10名志愿者均成功实现了非对比剂肝门静脉血管成像。TI由1200~1600 ms,门静脉远端分支的信号强度逐渐增强。在TI=1400 ms时,肝门静脉血管与肝实质之间的相对信号强度最高。结论3.0T MRI可以实现非对比剂肝门静脉血管成像,TI为1400 ms时成像效果较好。

  14. Usefulness of CT angiography in diagnosing acute gastrointestinal bleeding:A meta-analysis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    AIM: To analyze the accuracy of computed tomography (CT) angiography in the diagnosis of acute gastrointestinal (GI) bleeding. METHODS: The MEDLINE, EMBASE, Cancerlit, Cochrane Library database, Sciencedirect, Springerlink and Scopus, from January 1995 to December 2009, were searched for studies evaluating the accuracy of CT angiography in diagnosing acute GI bleeding. Studies were included if the ycompared CT angiography to a reference standard of upper GI endoscopy, colonoscopy, angiography or surgery in ...

  15. Correlation between coronary computed tomographic angiography and fractional flow reserve

    DEFF Research Database (Denmark)

    Kristensen, Thomas Skaarup; Engstrøm, Thomas; Kelbæk, Henning

    2010-01-01

    Coronary CT angiography (CCTA) has become an important modality to evaluate the presence of coronary artery disease. Coronary artery stenosis of intermediate severity remains a therapeutic dilemma. Measurement of fractional flow reserve (FFR) during coronary angiography is the most established...... technique to determine the hemodynamic severity of a coronary artery lesion. The aim of this study was to compare CCTA with FFR....

  16. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... can interfere with the magnetic field of the MRI unit. The magnetic field is not harmful in ... malfunction or cause problems during the examination. Most MRI exams are relatively painless. However, some patients may ...

  17. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Site Index A-Z Spotlight Recently posted: Anal Cancer Facet Joint Block Video: CT of the Heart ... Therapy Video: CT of the Sinuses Video: Colorectal Cancer Screening Radiology and You Sponsored by Image/Video ...

  18. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Index A-Z Spotlight October is National Breast Cancer Awareness Month Recently posted: Medical Imaging Costs Magnetoencephalography ( ... for your attention! Spotlight October is National Breast Cancer Awareness Month Recently posted: Medical Imaging Costs Magnetoencephalography ( ...

  19. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Resources Professions Site Index A-Z Spotlight September is National Ovarian Cancer Awareness Month September is National Prostate Cancer Awareness Month Recently posted: Medical ...

  20. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... About Us News Physician Resources Professions Site Index A-Z Spotlight Recently posted: Anal Cancer Facet Joint ... dot org Hello, I’m Dr. Elliot Fishman, a radiologist at Johns Hopkins Hospital in Baltimore, Maryland. ...

  1. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... A-Z Spotlight October is National Breast Cancer Awareness Month Recently posted: Medical Imaging Costs Magnetoencephalography (MEG) ... your attention! Spotlight October is National Breast Cancer Awareness Month Recently posted: Medical Imaging Costs Magnetoencephalography (MEG) ...

  2. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Index A-Z Spotlight September is National Ovarian Cancer Awareness Month September is National Prostate Cancer Awareness Month Recently posted: Magnetoencephalography (MEG) Venous Insufficiency ( ...

  3. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Spotlight September ... the examination. First of all, discuss with your doctor any serious health problems, recent surgeries and allergies. ...

  4. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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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 ... it’s commonly known, MRA. MRA is a noninvasive test that uses a powerful magnetic field and a ...

  5. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Index A-Z Spotlight September is National Ovarian Cancer Awareness Month September is National Prostate Cancer Awareness Month Recently posted: Medical Imaging Costs Magnetoencephalography ( ...

  6. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... an MRA scan, there are several things you can do to prepare for the examination. First of ... medical devices implanted in your body as these can interfere with the magnetic field of the MRI ...

  7. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Site Index A-Z Spotlight October is National Breast Cancer Awareness Month Recently posted: Medical Imaging Costs Magnetoencephalography ( ... and for your attention! Spotlight October is National Breast Cancer Awareness Month Recently posted: Medical Imaging Costs Magnetoencephalography ( ...

  8. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... computer to produce detailed pictures of the major blood vessels throughout your body. It may be performed with ... in your arm. MRA is used to examine blood vessels in key areas of your body and to ...

  9. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... About Us News Physician Resources Professions Site Index A-Z Spotlight October is National Breast Cancer Awareness ... dot org Hello, I’m Dr. Elliot Fishman, a radiologist at Johns Hopkins Hospital in Baltimore, Maryland. ...

  10. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... it’s commonly known, MRA. MRA is a noninvasive test that uses a powerful magnetic field and a ...

  11. Digital subtraction angiography of the thoracic aorta

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-02-01

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

  12. Pedal angiography in peripheral arterial occlusive disease: first-pass i.v. contrast-enhanced MR angiography with blood pool contrast medium versus intraarterial digital subtraction angiography.

    Science.gov (United States)

    Kos, Sebastian; Reisinger, Clemens; Aschwanden, Markus; Bongartz, Georg M; Jacob, Augustinus L; Bilecen, Deniz

    2009-03-01

    The purpose of this study was to prospectively evaluate first-pass i.v. gadofosveset-enhanced MR angiography in patients with peripheral arterial occlusive disease for visualization of the pedal arteries and stenosis or occlusion of those arteries with intraarterial digital subtraction angiography as the reference standard. Twenty patients with peripheral arterial occlusive disease (nine women, 11 men; age-range 58-83 years) were prospectively enrolled. Gadofosveset first-pass contrast-enhanced MR angiography was performed with a 1.5-T system, a dedicated foot coil, and cuff compression to the calf. Arterial segments were assessed for degree of arterial stenosis, arterial visibility, diagnostic utility, and venous contamination. Detection of vessel stenosis or occlusion was evaluated in comparison with findings at digital subtraction angiography. The unpaired Student's t test was used to test arterial visibility with the two techniques. First-pass MR angiography with gadofosveset had good diagnostic utility in 83.9% of all segments and no venous contamination in 96.8% of all segments. There was no difference between the performance of intraarterial digital subtraction angiography and that of i.v. contrast-enhanced MR angiography in arterial visibility overall (p = 0.245) or in subgroup analysis of surgical arterial bypass targets (p = 0.202). The overall sensitivity, specificity, and accuracy of i.v. gadofosveset-enhanced MR angiography for characterization of clinically significant stenosis and occlusion were 91.4%, 96.1%, and 93.9%. In the subgroup analysis, the sensitivity, specificity, and accuracy were 85.5%, 96.5%, and 92.1%. Gadofosveset-enhanced MR angiography of the pedal arteries in patients with peripheral arterial occlusive disease has arterial visibility equal to that of digital subtraction angiography and facilitates depiction of clinically significant stenosis and occlusion.

  13. Interaction of magnetic resonators studied by the magnetic field enhancement

    Science.gov (United States)

    Hou, Yumin

    2013-12-01

    It is the first time that the magnetic field enhancement (MFE) is used to study the interaction of magnetic resonators (MRs), which is more sensitive than previous parameters-shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  14. Interaction of magnetic resonators studied by the magnetic field enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Yumin, E-mail: ymhou@pku.edu.cn [State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)

    2013-12-15

    It is the first time that the magnetic field enhancement (MFE) is used to study the interaction of magnetic resonators (MRs), which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  15. Interaction of magnetic resonators studied by the magnetic field enhancement

    Directory of Open Access Journals (Sweden)

    Yumin Hou

    2013-12-01

    Full Text Available It is the first time that the magnetic field enhancement (MFE is used to study the interaction of magnetic resonators (MRs, which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  16. Analysis of coronary angiography related psychophysiological responses

    Directory of Open Access Journals (Sweden)

    Kaya Mehmet G

    2011-08-01

    Full Text Available Abstract Background Coronary angiography is an important tool in diagnosis of cardiovascular diseases. However, it is the administration is relatively stressful and emotionally traumatic for the subjects. The aim of this study is to evaluate psychophysiological responses induced by the coronary angiography instead of subjective methods such as a questionnaire. We have also evaluated the influence of the tranquilizer on the psychophysiological responses. Methods Electrocardiography (ECG, Blood Volume Pulse (BVP, and Galvanic Skin Response (GSR of 34 patients who underwent coronary angiography operation were recorded. Recordings were done at three phases: "1 hour before," "during," and "1 hour after" the coronary angiography test. Total of 5 features obtained from the physiological signals were compared across these three phases. Sixteen of the patients were administered 5 mg of a tranquilizer (Diazepam before the operation and remaining 18 were not. Results Our results indicate that there is a strong correlation between features (LF/HF, Bk, DN1/DN2, skin conductance level and seg_mean in terms of reflecting psychophysiological responses. However only DN1/DN2 feature has statistically significant differences between angiography phases (for diazepam: p = 0.0201, for non_diazepam p = 0.0224. We also note that there are statistically significant differences between the diazepam and non-diazepam groups for seg_mean features in "before", "during" and "after" phases (p = 0.0156, 0.0282, and 0.0443, respectively. Conclusions The most intense sympathetic activity is observed in the "during" angiography phase for both of the groups. The obtained features can be used in some clinical studies where generation of the customized/individual diagnoses styles and quantitative evaluation of psychophysiological responses is necessary.

  17. Magnetic Resonance Imaging Studies of Postpartum Depression: An Overview

    Directory of Open Access Journals (Sweden)

    Marco Fiorelli

    2015-01-01

    Full Text Available Postpartum depression is a frequent and disabling condition whose pathophysiology is still unclear. In recent years, the study of the neural correlates of mental disorders has been increasingly approached using magnetic resonance techniques. In this review we synthesize the results from studies on postpartum depression in the context of structural, functional, and spectroscopic magnetic resonance studies of major depression as a whole. Compared to the relative wealth of data available for major depression, magnetic resonance studies of postpartum depression are limited in number and design. A systematic literature search yielded only eleven studies conducted on about one hundred mothers with postpartum depression overall. Brain magnetic resonance findings in postpartum depression appear to replicate those obtained in major depression, with minor deviations that are not sufficient to delineate a distinct neurobiological profile for this condition, due to the small samples used and the lack of direct comparisons with subjects with major depression. However, it seems reasonable to expect that studies conducted in larger populations, and using a larger variety of brain magnetic resonance techniques than has been done so far, might allow for the identification of neuroimaging signatures for postpartum depression.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-04-01

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

  19. Normal values of left ventricularmass and cardiac chamber volumes assessed by 320-detector computed tomography angiography in the Copenhagen General Population Study

    DEFF Research Database (Denmark)

    Fuchs, Andreas; Mejdahl, Mads Rams; Kühl, J Tobias

    2016-01-01

    Aims Normal values of left ventricular mass (LVM) and cardiac chamber sizes are prerequisites for the diagnosis of individuals with heart disease. LVM and cardiac chamber sizes may be recorded during cardiac computed tomography angiography (CCTA), and thus modality specific normal values are needed....... Methods and results We studied 569 healthy subjects undergoing 320-detector CCTA as a part of the Copenhagen General Population Study. LVM as well as ventricular and atrial volumes was assessed with semi-automated software stratified by gender and age decades and indexed by body surface area (BSA). Mean...... blood pressure, and hard physical activity accounted for 63% of variance in LVM. Conclusion In this cross-sectional general population study, men have greater indexed LVM and chamber volumes than women, and cardiac indexed volumes vary between age groups in both genders. These findings demonstrate...

  20. Artefacts induced by coiled intracranial aneurysms on 3.0-Tesla versus 1.5-Tesla MR angiography--An in vivo and in vitro study.

    Science.gov (United States)

    Schaafsma, Joanna D; Velthuis, Birgitta K; Vincken, Koen L; de Kort, Gerard A P; Rinkel, Gabriel J E; Bartels, Lambertus W

    2014-05-01

    To compare metal-induced artefacts from coiled intracranial aneurysms on 3.0-Tesla and 1.5-Tesla magnetic resonance angiography (MRA), since concerns persist on artefact enlargement at 3.0Tesla. We scanned 19 patients (mean age 53; 16 women) with 20 saccular aneurysms treated with coils only, at 1.5 and 3.0Tesla according to standard clinical 3D TOF-MRA protocols containing a shorter echo-time but weaker read-out gradient at 3.0Tesla in addition to intra-arterial digital subtraction angiography (IA-DSA). Per modality two neuro-radiologists assessed the occlusion status, measured residual flow, and indicated whether coil artefacts disturbed this assessment on MRA. We assessed relative risks for disturbance by coil artefacts, weighted kappa's for agreement on occlusion levels, and we compared remnant sizes. For artefact measurements, a coil model was created and scanned with the same protocols followed by 2D MR scans with variation of echo-time and read-out gradient strength. Coil artefacts disturbed assessments less frequently at 3.0Tesla than at 1.5Tesla (RR: 0.3; 95%CI: 0.1-0.8). On 3.0-Tesla MRA, remnants were larger than on 1.5-Tesla MRA (difference: 0.7mm; 95%CI: 0.3-1.1) and larger than on IA-DSA (difference: 1.0mm; 95%CI: 0.6-1.5) with similar agreement on occlusion levels with IA-DSA for both field strengths (κ 0.53; 95%CI: 0.23-0.84 for 1.5-Tesla MRA and IA-DSA; κ 0.47; 95%CI: 0.19-0.76 for 3.0-Tesla MRA and IA-DSA). Coil model artefacts were smaller at 3.0Tesla than at 1.5Tesla. The echo-time influenced artefact size more than the read-out gradient. Artefacts were not larger, but smaller at 3.0Tesla because a shorter echo-time at 3.0Tesla negated artefact enlargement. Despite smaller artefacts and larger remnants at 3.0Tesla, occlusion levels were similar for both field strengths. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  1. Value of MR angiography of Adamkiewicz artery as a preoperative investigation for thoracic-descending and thoracoabdominal aortic aneurysms. Retrospective study of 106 cases

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Naoaki; Ogino, Hitoshi; Hanabusa, Yuji; Sasaki, Hiroaki; Minatoya Kenji [National Cardiovascular Center, Suita, Osaka (Japan)

    2003-01-01

    We reviewed 106 cases who underwent MR angiography to visualize the Adamkiewicz artery (AKA) as a preoperative evaluation of the thoracic descending and thoracoabdominal aortic aneurysms. MR angiography depicted the AKA successfully in 68% of the patients. However, segmental artery that gives rise the AKA was occluded in 41% at its origin from the aorta. In one patient with postoperative paraplegia, broad infarction in the upper thoracic cord seems not to be related to the territory of the AKA that was visualized by MR angiography. Preoperative MR angiography serves planning of surgery, and can reduce time of aortic cross-clamping. However, our understanding of the value of MR angiography to prevent spinal cord ischemic injury requires further clinical investigation. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-08-01

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

  4. The role of MR angiography in neuroradiology

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-09-01

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

  5. Relaxation response in femoral angiography.

    Science.gov (United States)

    Mandle, C L; Domar, A D; Harrington, D P; Leserman, J; Bozadjian, E M; Friedman, R; Benson, H

    1990-03-01

    Immediately before they underwent femoral angiography, 45 patients were given one of three types of audiotapes: a relaxation response tape recorded for this study, a tape of contemporary instrumental music, or a blank tape. All patients were instructed to listen to their audiotape during the entire angiographic procedure. Each audiotape was played through earphones. Radiologists were not told the group assignment or tape contents. The patients given the audiotape with instructions to elicit the relaxation response (n = 15) experienced significantly less anxiety (P less than .05) and pain (P less than .001) during the procedure, were observed by radiology nurses to exhibit significantly less pain (P less than .001) and anxiety (P less than .001), and requested significantly less fentanyl citrate (P less than .01) and diazepam (P less than .01) than patients given either the music (n = 14) or the blank (n = 16) control audiotapes. Elicitation of the relaxation response is a simple, inexpensive, efficacious, and practical method to reduce pain, anxiety, and medication during femoral angiography and may be useful in other invasive procedures.

  6. Transient Global Amnesia After Cerebral Angiography With Iomeprol

    Science.gov (United States)

    Tiu, Cristina; Terecoasă, Elena Oana; Grecu, Nicolae; Dorobăţ, Bogdan; Marinescu, Andreea Nicoleta; Băjenaru, Ovidiu Alexandru

    2016-01-01

    Abstract Transient global amnesia is now considered a very rare complication of cerebral angiography. Various etiological mechanisms have been suggested to account for this complication, but no consensus has been reached yet. This case report documents one of the few reported cases of cerebral angiography-related transient global amnesia associated with magnetic resonance imaging (MRI) evidence of unilateral hippocampal ischemia, most probably as a consequence of a transient reduction in regional hippocampal blood flow. However, the possibility of a direct neurotoxic effect of the nonionic contrast media Iomeprol on the Cornu ammonis – field 1 neurons cannot be firmly ruled out. We describe the case of a 54-year-old woman admitted to our department for left upper limb weakness with acute onset 8 days before. The brain computed tomography (CT) scan performed at admission revealed subacute ischemic lesions in the right watershed superficial territories and a right thalamic lacunar infarct. Diagnostic digital subtraction cerebral angiography was performed 4 days after admission with the nonionic contrast media Iomeprol. A few minutes after completion of the procedure, the patient developed symptoms suggestive for transient global amnesia. The brain MRI performed 22 hours after the onset of symptoms demonstrated increased signal within the lateral part of the right hippocampus on the diffusion-weighted imaging (DWI) sequences, associated with a corresponding reduction in the apparent diffusion coefficient (ADC) and increased signal on the fluid-attenuated inversion recovery (FLAIR) sequences, consistent with acute hippocampal ischemia and several T2/FLAIR hyperintensities in the right watershed superficial territories and in the right thalamus, corresponding to the lesions already identified on the CT scan performed at admission. A follow-up MRI, performed 2 months later, demonstrated the disappearance of the increased signal within the right hippocampus on the DWI

  7. Evaluation of middle cerebral artery stents using multidetector row CT angiography in vivo study: comparison of the three different kernels

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jin Hee; Lim, Yeon Soo; Lee, Youn Joo; Yoo, Won Jong; Sung, Mi Sook (Dept. of Radiology, Bucheon St Mary' s Hospital, Coll. of Medicine, The Catholic Univ. of Korea, Bucheon (Korea, Republic of)), email: wjyu@catholic.ac.kr; Kim, Bum Soo (Dept. of Radiology, Seoul St Mary' s Hospital, Coll. of Medicine, The Catholic Univ. of Korea, Seoul (Korea, Republic of))

    2012-05-15

    Background: There are very few reports assessing middle cerebral artery (MCA) stents using multidetector computed tomography (MDCT). Purpose: To assess MCA stents using multidetector CT angiography (CTA) in vivo evaluation: the differences in the CTA results according to the three different kernels. Material and Methods: We retrospectively evaluated 27 MCA stents from 26 patients who underwent CTA with 16- and 64-slice MDCT after percutaneous transluminal angioplasty and stenting (PTAS). By CTA, using medium-smooth kernel (B30), medium-sharp kernel (B50), and sharp kernel (B60), the lumen diameter, artificial luminal narrowing (ALN), and subjective visibility score of the stented vessels were evaluated. The subjective visibility score ranged from 1 (poor quality) to 5 (excellent) using a five-point scale. Results: There were excellent inter-observer agreements for the lumen diameter measurements (P < 0.001). The mean diameter of the stented vessels was 2.10 +- 0.31 mm on digital subtraction angiography (DSA), 0.93 +- 0.20 mm on CTA using B30, 1.18 +- 0.27 mm on CTA using B50, and 1.29 +- 0.29 mm on CTA using B60. The mean ALN was 55.7 +- 6.0% on CTA using B30, 43.8 +- 7.5% on CTA using B50, and 38.7 +- 8.3% on CTA using B60. CTA with higher kernels had a smaller ALN than images with smaller kernels. The median subjective visibility score on the CTA using B50 was 3, which was higher than for the other kernels. The differences in the lumen diameter, ALN, and the subjective visibility score of the stented vessels on CTA using the three different kernels was statistically significant (P < 0.001). Conclusion: The sharp kernel was better to assess the lumen diameter and ALN, but was inferior to the medium-sharp kernel for in-stent evaluation due to high image-to-noise. CTA with medium-sharp kernel showed good lumen visibility and acceptable ALN for MCA stents. This could therefore be a non-invasive, readily applicable clinical method for assessing MCA stent patency after

  8. Magnetic resonance studies of solid polymers; Etude des polymeres solides par resonance magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Lenk, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    This paper is a review of the application of nuclear magnetic resonance (NMR) to solid polymers. In the first, theoretical part, the elements of the theory of NMR, which are necessary for the study of the properties of solid polymers are discussed: the moments method, nuclear relaxation and the distribution of correlation times. In the second part the experimental results are presented. (author) [French] Cette etude est une recherche bibliographique sur l'application de la resonance magnetique nucleaire (RMN) aux polymeres solides. Dans la premiere partie theorique on discute les elements de la theorie de RMN, necessaires pour l'etude des proprietes des polymeres solides: la methode des moments, la relaxation nucleaire et la distribution des temps de correlation. La deuxieme partie presente les resultats des experiences. (auteur)

  9. Reproducibility of coronary plaque detection and characterization using low radiation dose coronary computed tomographic angiography in patients with intermediate likelihood of coronary artery disease (ReSCAN study)

    DEFF Research Database (Denmark)

    Ovrehus, Kristian Altern; Marwan, Mohamed; Bøtker, Hans Erik

    2012-01-01

    The purpose of this study is to evaluate the interscan, interobserver and intraobserver agreement for coronary plaque detection, and characterization using low radiation dose high-pitch spiral acquisition coronary CT angiography (CTA). Two experienced observers independently evaluated coronary CTA......-values 0.57-0.85), and 67-84% (0.31-0.67) for non-calcified plaques on a patient level. No significant difference was observed in mean interscan or interobserver SIS. Mean (95% CI) intraobserver SIS difference was -0.88 (-1.25; -0.51), P Low radiation dose...... datasets from 50 consecutive patients undergoing two 128-slice dual source CT scans within 12 days. Mean (±SD) estimated radiation exposure was 1.5 ± 0.2 mSv per scan. Observers recorded the presence and characterization of coronary plaques as non-calcified or calcified. A "segment involvement score" (SIS...

  10. Studying the $\\rho$ resonance parameters with staggered fermions

    CERN Document Server

    Fu, Ziwen

    2016-01-01

    We deliver a lattice study of $\\rho$ resonance parameters with p-wave $\\pi\\pi$ scattering phases, which are extracted by finite-size methods at one center-of-mass frame and four moving frames for six MILC lattice ensembles with pion masses ranging from $346$ to $ 176$ MeV. The effective range formula is applied to describe the scattering phases as a function of the energy covering the resonance region, this allows us to extract $\\rho$ resonance parameters and to investigate the quark-mass dependence. Lattice studies with three flavors of the Asqtad-improved staggered fermions enable us to use the moving-wall source technique on large lattice spatial dimensions ($L=64$) and small light $u/d$ quarks. Numerical computations are carried out at two lattice spacings, $a \\approx 0.12$ and $0.09$ fm.

  11. Studying the ρ resonance parameters with staggered fermions

    Science.gov (United States)

    Fu, Ziwen; Wang, Lingyun

    2016-08-01

    We deliver a lattice study of ρ resonance parameters with p -wave π π scattering phases, which are extracted by finite-size methods at one center-of-mass frame and four moving frames for six lattice ensembles from the MILC Collaboration with pion masses ranging from 346 to 176 MeV. The effective range formula is applied to describe the scattering phases as a function of the energy covering the resonance region; this allows us to extract ρ resonance parameters and to investigate the quark-mass dependence. Lattice studies with three flavors of Asqtad-improved staggered fermions enable us to use the moving-wall source technique on large lattice spatial dimensions (L =64 ) and small light u /d quarks. Numerical computations are carried out at two lattice spacings, a ≈0.12 and 0.09 fm.

  12. Evaluation of fast highly undersampled contrast-enhanced MR angiography (sparse CE-MRA) in intracranial applications - initial study

    Energy Technology Data Exchange (ETDEWEB)

    Gratz, Marcel; Quick, Harald H. [University of Duisburg-Essen, Erwin L. Hahn Institute for MR Imaging, Essen (Germany); University Hospital Essen, High Field and Hybrid MR Imaging, Essen (Germany); Schlamann, Marc [University Hospital Giessen and Marburg GmbH, Neuroradiology, Giessen (Germany); University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Goericke, Sophia [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Maderwald, Stefan [University of Duisburg-Essen, Erwin L. Hahn Institute for MR Imaging, Essen (Germany)

    2017-03-15

    To assess the image quality of sparsely sampled contrast-enhanced MR angiography (sparse CE-MRA) providing high spatial resolution and whole-head coverage. Twenty-three patients scheduled for contrast-enhanced MR imaging of the head, (N = 19 with intracranial pathologies, N = 9 with vascular diseases), were included. Sparse CE-MRA at 3 Tesla was conducted using a single dose of contrast agent. Two neuroradiologists independently evaluated the data regarding vascular visibility and diagnostic value of overall 24 parameters and vascular segments on a 5-point ordinary scale (5 = very good, 1 = insufficient vascular visibility). Contrast bolus timing and the resulting arterio-venous overlap was also evaluated. Where available (N = 9), sparse CE-MRA was compared to intracranial Time-of-Flight MRA. The overall rating across all patients for sparse CE-MRA was 3.50 ± 1.07. Direct influence of the contrast bolus timing on the resulting image quality was observed. Overall mean vascular visibility and image quality across different features was rated good to intermediate (3.56 ± 0.95). The average performance of intracranial Time-of-Flight was rated 3.84 ± 0.87 across all patients and 3.54 ± 0.62 across all features. Sparse CE-MRA provides high-quality 3D MRA with high spatial resolution and whole-head coverage within short acquisition time. Accurate contrast bolus timing is mandatory. (orig.)

  13. Chinese multi-center study of lung scintigraphy and CT pulmonary angiography for the diagnosis of pulmonary embolism.

    Science.gov (United States)

    He, Jia; Wang, Feng; Dai, Hao-jie; Li, Mei; Wang, Qian; Yao, Zhiming; Lv, Bin; Xiong, Chang-ming; He, Jian-guo; Liu, Zhi-hong; He, Zuo-Xiang; Fang, Wei

    2012-10-01

    To evaluate diagnostic value of the PISA-PED and PIOPED II criteria for lung scintigraphy and compare it with CT pulmonary angiography (CTPA) for the detection of pulmonary embolism (PE). Five hundred and forty-four consecutive patients with suspected PE were enrolled. All patients underwent lung ventilation/perfusion (V/P) scan, chest radiography, and CTPA. Two readers used the PIOPED II criteria, and 2 used the PISA-PED criteria for the interpretation of lung scintigraphy. CTPA scans were interpreted by two experienced radiologists. Lung scintigraphy and CTPA were categorized as PE present, absent or non-diagnostic. PE was present in 321 of 544 patients. Using PIOPED II criteria, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 85.1, 82.5, 88.1, and 78.4% respectively for V/P scan. Using PISA-PED criteria, sensitivity, specificity, PPV, and NPV were 86.0, 81.2, 86.8, and 80.1% respectively, and none was non-diagnostic. Sensitivity, specificity, PPV, and NPV were 81.7, 93.4, 94.9, and 77.3%, respectively for CTPA. PISA-PED interpretation has similar diagnostic accuracy to PIOPED II interpretation, does not have non-diagnostic scan, with lower cost and radiation, thus should be considered as a choice for patients with suspected PE.

  14. Nonenhanced MR Angiography of the Hand with Flow-Sensitive Dephasing–prepared Balanced SSFP Sequence: Initial Experience with Systemic Sclerosis

    Science.gov (United States)

    Fan, Zhaoyang; Davarpanah, Amir H.; Hodnett, Philip A.; Varga, John; Carr, James C.; Li, Debiao

    2011-01-01

    Purpose: To compare the image quality and degree of vessel narrowing at flow-sensitive dephasing (FSD) magnetic resonance (MR) angiography of the hands with those at contrast material–enhanced MR angiography of the hands in patients with systemic sclerosis. Materials and Methods: In a single-center study with institutional review board approval and HIPAA compliance, six healthy volunteers and six patients with systemic sclerosis were imaged at 1.5-T nonenhanced FSD MR angiography followed by contrast-enhanced MR angiography. Sixteen vascular segments in four vessel groups were evaluated for image quality and assessed semiquantitatively for stenosis degree by using Likert scales. The nonparametric Wilcoxon signed rank test was used to perform pairwise comparisons of the MR angiographic techniques. P MR angiography, as compared with time-resolved MR angiography and high-spatial-resolution MR angiography, improved the image quality for all arterial segments combined in the control (mean score, 2.9 [FSD] vs 3.7 [time-resolved technique] and 3.1 [high-spatial-resolution technique]) and patient (mean score, 4.0 [FSD] vs 4.2 [time-resolved technique] and 4.3 [high-spatial-resolution technique]) groups. In the control subjects, FSD angiography depicted proper digital artery stenosis that was less severe (mean grade, 0.7) than that seen with the time-resolved (mean grade, 1.6) and high-spatial-resolution (mean grade, 1.0) techniques. In the patient group, FSD angiography depicted lower degrees of stenosis, with a lower mean grade for all segments combined (1.3) compared with the corresponding mean grades for time-resolved (1.5) and high-spatial-resolution (1.8) MR angiography. Conclusion: Preliminary data indicate that the proposed nonenhanced FSD MR angiographic technique is an improvement over existing contrast-enhanced techniques for evaluation of the hand vasculature in vasospastic disorders of the hand. Further technical improvements and a systematic clinical study

  15. 320-row CT coronary angiography predicts freedom from revascularisation and acts as a gatekeeper to defer invasive angiography in stable coronary artery disease: a fractional flow reserve-correlated study

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Brian S.; Wong, Dennis T.L.; Cameron, James D.; Leung, Michael; Meredith, Ian T.; Nerlekar, Nitesh; Antonis, Paul; Harper, Richard; Malaiapan, Yuvaraj; Seneviratne, Sujith K. [Southern Health and Monash University, Monash Cardiovascular Research Centre, MonashHEART, Department of Medicine Monash Medical Centre (MMC), Melbourne (Australia); Leong, Darryl P. [University of Adelaide, Discipline of Medicine, Adelaide (Australia); Flinders University, Adelaide (Australia); Crossett, Marcus; Troupis, John [Southern Health and Monash University, Monash Cardiovascular Research Centre, MonashHEART, Department of Medicine Monash Medical Centre (MMC), Melbourne (Australia); Southern Health and Monash University, Department of Diagnostic Imaging, MMC, Melbourne (Australia)

    2014-03-15

    To determine the accuracy of 320-row multidetector coronary computed tomography angiography (M320-CCTA) to detect functional stenoses using fractional flow reserve (FFR) as the reference standard and to predict revascularisation in stable coronary artery disease. One hundred and fifteen patients (230 vessels) underwent M320-CCTA and FFR assessment and were followed for 18 months. Diameter stenosis on invasive angiography (ICA) and M320-CCTA were assessed by consensus by two observers and significant stenosis was defined as ≥50 %. FFR ≤0.8 indicated functionally significant stenoses. M320-CCTA had 94 % sensitivity and 94 % negative predictive value (NPV) for FFR ≤0.8. Overall accuracy was 70 %, specificity 54 % and positive predictive value 65 %. On receiver operating characteristic (ROC) curve analysis, the area under the curve (AUC) for CCTA to predict FFR ≤0.8 was 0.74 which was comparable with ICA. The absence of a significant stenosis on M320-CCTA was associated with a 6 % revascularisation rate. M320-CCTA predicted revascularisation with an AUC of 0.71 which was comparable with ICA. M320-CCTA has excellent sensitivity and NPV for functional stenoses and therefore may act as an effective gatekeeper to defer ICA and revascularisation. Like ICA, M320-CCTA lacks specificity for functional stenoses and only has moderate accuracy to predict the need for revascularisation. (orig.)

  16. Magnetic resonance imaging study of corpus callosum ...

    African Journals Online (AJOL)

    2014-11-02

    Nov 2, 2014 ... gender and callosal measures in patient and control groups. In all groups of ..... our intelligence and problem-solving ability. The prefrontal cortex plays a role in the regulation of complex cognitive, emotional and .... in the corpus callosum in abuse-related posttraumatic stress disorder: A preliminary study. J.

  17. Gadofosveset-enhanced MR angiography of carotid arteries: does steady-state imaging improve accuracy of first-pass imaging? Comparison with selective digital subtraction angiography.

    Science.gov (United States)

    Anzidei, Michele; Napoli, Alessandro; Marincola, Beatrice Cavallo; Nofroni, Italo; Geiger, Daniel; Zaccagna, Fulvio; Catalano, Carlo; Passariello, Roberto

    2009-05-01

    To evaluate the diagnostic accuracy of gadofosveset-enhanced magnetic resonance (MR) angiography in the assessment of carotid artery stenosis, with digital subtraction angiography (DSA) as the reference standard, and to determine the value of reading first-pass, steady-state, and "combined" (first-pass plus steady-state) MR angiograms. This study was approved by the local ethics committee, and all subjects gave written informed consent. MR angiography and DSA were performed in 84 patients (56 men, 28 women; age range, 61-76 years) with carotid artery stenosis at Doppler ultrasonography. Three readers reviewed the first-pass, steady-state, and combined MR data sets, and one independent observer evaluated the DSA images to assess stenosis degree, plaque morphology and ulceration, stenosis length, and tandem lesions. Interobserver agreement regarding MR angiographic findings was analyzed by using intraclass correlation and Cohen kappa coefficients. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated by using the McNemar test to determine possible significant differences (P < .05). Interobserver agreement regarding all MR angiogram readings was substantial. For grading stenosis, sensitivity, specificity, PPV, and NPV were, respectively, 90%, 92%, 91%, and 91% for first-pass imaging; 95% each for steady-state imaging; and 96%, 99%, 99%, and 97% for combined imaging. For evaluation of plaque morphology, respective values were 84%, 86%, 88%, and 82% for first-pass imaging; 98%, 97%, 98%, and 97% for steady-state imaging; and 98%, 100%, 100%, and 97% for combined imaging. Differences between the first-pass, steady-state, and combined image readings for assessment of stenosis degree and plaque morphology were significant (P < .001). Gadofosveset-enhanced MR angiography is a promising technique for imaging carotid artery stenosis. Steady-state image reading is superior to first-pass image reading, but the combined

  18. Combining Coronary Angiography and Myocardial Perfusion by Computed Tomography in the Identification of Flow-Limiting Stenosis – The CORE320 study

    Science.gov (United States)

    Magalhães, Tiago A.; Kishi, Satoru; George, Richard; Arbab-Zadeh, Armin; Vavere, Andrea; Cox, Christopher; Matheson, Matthew B.; Miller, Julie; Brinker, Jeffrey; Di Carli, Marcelo; Rybicki, Frank J.; Rochitte, Carlos E.; Clouse, Melvin; Lima, João A.C.

    2015-01-01

    Background The combination of coronary computed tomography angiography (CTA) and myocardial CT perfusion (CTP) is gaining increasing acceptance, but a standardized approach to be implemented in the clinical setting is necessary. Objectives To investigate the accuracy of a combined coronary CTA and myocardial CTP comprehensive protocol compared to coronary CTA alone, using a combination of invasive coronary angiography (ICA) and Single-Photon Emission Computed Tomography (SPECT) as reference. Methods Three-hundred eighty-one patients included in CORE320 trial were analyzed in this study. Flow-limiting stenosis was defined as the presence of ≥50% stenosis by ICA with a related perfusion deficit by SPECT. The combined CTA+CTP definition of disease was the presence of a ≥50% stenosis with a related perfusion deficit. All data sets were analyzed by two experienced readers, aligning anatomical findings by CTA with perfusion deficits by CTP. Results Mean patient age was 62±6 years (66% male), 27% with prior history of myocardial infarction. In a per-patient analysis, sensitivity for CTA alone was 93% specificity was 54%, positive predictive value (PPV) was 55%; negative predictive value (NPV) 93% and overall accuracy was 69%. After combining CTA and CTP, sensitivity was 78%, specificity 73%, NPV 64%; PPV 0.85% and overall accuracy was 75%. In a per-vessel analysis, overall accuracy of CTA alone was 73%as compared to 79% for the combination of CTA and CTP (pcoronary CTA and myocardial CTP findings through a comprehensive protocol is feasible. While sensitivity is lower, specificity and overall accuracy are higher than assessment by coronary CTA when compared against a reference standard of stenosis with an associated perfusion deficit. PMID:25977111

  19. Utilization of cardiac computed tomography angiography and outpatient invasive coronary angiography in Ontario, Canada.

    Science.gov (United States)

    Roifman, Idan; Rezai, Mohammad R; Wijeysundera, Harindra C; Chow, Benjamin J W; Wright, Graham A; Tu, Jack V

    2015-01-01

    Cardiac computed tomography angiography (coronary CTA) has emerged as a non-invasive method of diagnosing coronary artery disease. The extent of utilization and uptake of this technology since initiation of its funding by the government of Ontario is unknown. The aim of our study was to examine coronary CTA utilization and the rates of elective invasive coronary angiography and revascularization before and after funding initiation. We studied all coronary CTAs performed on adults in Ontario after initiation of funding. We also used an interrupted time series analysis to compare the average monthly rates of invasive angiography and revascularization before and after initiation of funding. There was an initial steep increase in age-and sex-standardized rates of coronary CTA from 5.0 to 11.4/100,000 over the first two quarters after funding initiation. Afterwards, there was a gradual increase in utilization from 11.4 to 17.1/100,000 over two subsequent calendar years. There was a significant reduction in both the mean monthly outpatient invasive coronary angiography (from 20.7 to 19.9 per 100,000 (p = 0.0004)) and revascularization (from 4.9 to 4.4 per 100,000 (p utilization. The increasing use of coronary CTA was associated with a reduction in both the rates of invasive angiography and revascularization. Copyright © 2015 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  20. Multimodality evaluation of dural arteriovenous fistula with CT angiography, MR with arterial spin labeling, and digital subtraction angiography: case report.

    Science.gov (United States)

    Alexander, Matthew; McTaggart, Ryan; Santarelli, Justin; Fischbein, Nancy; Marks, Michael; Zaharchuk, Greg; Do, Huy

    2014-01-01

    Dural arteriovenous fistulae (DAVF) are cerebrovascular lesions with pathologic shunting into the venous system from arterial feeders. Digital subtraction angiography (DSA) has long been considered the gold standard for diagnosis, but advances in noninvasive imaging techniques now play a role in the diagnosis of these complex lesions. Herein, we describe the case of a patient with right-side pulsatile tinnitus and DAVF diagnosed using computed tomography angiography, magnetic resonance with arterial spin labeling, and DSA. Implications for imaging analysis of DAVFs and further research are discussed.

  1. Magnetic Resonance Perfusion Imaging in the Study of Language

    Science.gov (United States)

    Hillis, Argye E.

    2007-01-01

    This paper provides a brief review of various uses of magnetic resonance perfusion imaging in the investigation of brain/language relationships. The reviewed studies illustrate how perfusion imaging can reveal areas of brain where dysfunction due to low blood flow is associated with specific language deficits, and where restoration of blood flow…

  2. Fluorescent blood cell angiography

    Science.gov (United States)

    Ben-nun, Joshua; Constable, Ian J.

    1994-06-01

    Fluorescein angiography is currently the main method for evaluation of the retinal vascular patency. Ashton noted that capillary patency to the small fluorescein molecule may differ from that of the larger red blood cells. He concluded that fluorescein angiography is not able to demonstrate a developing stenosis, that might be the precipitating cause of a later capillary closure in various microvasculopathies. Sarelius et al have shown, in hamster cheek pouch and cremaster muscle, that fluorescently labeled erythrocytes in known concentrations can be used for the direct measurement of capillary flow parameters. The only assumption that this method relies on, is that the labeled cells are rheologically normal and therefore reflect the behavior of the total cell population. We have developed a new method for an in-vivo, real-time demonstration of the blood cell flow in the retinal capillary net. Based on the assumption presented by Sarelius et al, measurement and analysis of the retinal capillary blood cell flow is also possible from the results achieved by the new method.

  3. Cardiac MRI in addition to MR angiography: a longitudinal study in vascular risk patients; Kardiale MRT als Ergaenzung zur MR-Angiografie: Eine longitudinale Studie bei vaskulaeren Risikopatienten

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, A.; Grimm, F.; Fenchel, M.; Kramer, U.; Doering, J.S.; Klumpp, B.; Claussen, C.D.; Miller, S. [Abt. fuer Radiologische Diagnostik, Eberhard-Karls-Univ. Tuebingen (Germany); Scheule, A. [Abt. fuer Herz-, Thorax- und Gefaesschirurgie, Eberhard-Karls-Univ. Tuebingen (Germany); May, A.E. [Abt. fuer Kardiologie, Eberhard-Karls-Univ. Tuebingen (Germany)

    2008-05-15

    Purpose: the aim of the study was to assess the feasibility and additional diagnostic information of cardiac MRI as a supplement to state-of-the-art MR angiography (MRA) in the case of vascular risk patients. Therefore, the prevalence of delayed myocardial enhancement (DE) was determined in patients suffering from peripheral artery disease (PAD) and a clinical follow-up was evaluated after 2 years. Materials and method: 87 consecutive patients (ages 66 {+-} 10 years, 67 males) with symptomatic peripheral arterial occlusive disease (n = 68) or abdominal aortic aneurysm (n = 19) were examined using delayed cardiac enhancement (DE) within the clinical indication of MRA at a 1.5T system. A follow-up examination was carried out two years later (24 months {+-} 4 months) with regards to cardiac events (cardiac death, myocardial infarction or acute coronary syndrome, heart insufficiency, coronary revascularization). Results: in total, 40/87 patients had myocardial infarctions shown in MRI (46%). In 25 patients (29%), the myocardial infarction was already known, while in 15 patients (17%) an occult progressing infarction was diagnosed (38% of the myocardial infarcts). Follow-up data was able to be obtained after 2 years for 82 patients. 15 patients had a major cardiac event during the follow-up period, and 10 (67%) of them already showed DE in the MRI. In the group with occult progressing infarctions, cardiac events occurred in 40% (6/15 patients, cardiac death n = 1, ischemia n = 4, heart insufficiency n = 1, bypass n = 1), in patients with known infarction in 17% (4/23 patients, cardiac death n = 1, ischemia n = 3, bypass n = 2) and in 11% of patients without myocardial scars (5/44 patients, cardiac death n = 1, ischemia n = 2, heart insufficiency n = 2). (orig.)

  4. Adverse reactions of fluorescein angiography: a prospective study Reações adversas na angiofluoresceinografia: estudo prospectivo

    Directory of Open Access Journals (Sweden)

    Rodrigo Pessoa Cavalcanti Lira

    2007-08-01

    Full Text Available PURPOSES: To determine both the incidence of adverse reactions in patients who underwent fluorescein angiography for the first time and to determine whether systemic arterial hypertension, diabetes or allergy history increases the chance of reaction to intravenous fluorescein. METHODS:Data collection was carried out between January 2001 and October 2002 in Recife, Brazil. Patients with prior fluorescein angiography history, pregnant patients or patients in use of corticosteroids, immunosuppressive or antihistamine drugs were excluded. RESULTS: Out of 1,500 enrolled patients, 1,039 (69.3% underwent the test for the first time. The mean age was 58 ± 16 years and the median age was 60 years. Of these, 628 (60.4% were women. Nausea occurred in 71 (6.83% patients, vomiting in 14 (1.35%, urticaria in 11 (1.06%, bronchospasm in 4 (0.38% and laryngeal edema in 1 (0.01%. Five patients presented more than one adverse reaction. Higher incidences of adverse reactions were observed in diabetic patients [pOBJETIVO: Determinar a incidência de reações adversas em pacientes submetidos à angiofluoresceinografia pela primeira vez e determinar se hipertensão arterial sistêmica, diabetes ou história de alergia aumentam a chance de reações à fluoresceína intravenosa. MÉTODOS: Os dados foram coletados entre janeiro de 2001 e outubro de 2002 em Recife, Brasil. Pacientes com angiofluoresceinografia prévia, gestantes ou pacientes em uso de medicamentos corticosteróides, imunossupressores ou anti-histamínicos foram excluídos. RESULTADOS: Dos 1.500 pacientes iniciais, 1.039 (69,3% realizavam o exame pela primeira vez. A idade média foi de 58 ± 16 anos e a mediana de 60 anos. Dentre esses, 628 (60,4% pessoas eram do sexo feminino. Náusea ocorreu em 71 (6,83% pacientes, vômito em 14 (1,35%, urticária em 11 (1,06%, broncoespasmo em 4 (0,38% e edema de laringe em 1 (0,01%. Cinco pacientes apresentaram mais de uma reação adversa. Maiores incidências de

  5. The role of preoperative angiography in the management of giant meningiomas associated to vascular malformation

    Directory of Open Access Journals (Sweden)

    Fabio Papacci

    2015-01-01

    Full Text Available Background: The role of preoperative digital subtraction angiography (DSA in meningiomas is currently under discussion because of the introduction of noninvasive magnetic resonance imaging (MRI angiography to study vascular anatomy associated to the tumor. Preoperative DSA is mainly performed to obtain embolization of the lesion, although a number of complications have been reported after this procedure. Nonetheless, the coexistence of meningiomas with vascular malformations has previously been reported and it has been evidenced that this event could be underestimated because of neglect of preoperative DSA. Here, we report on two challenging cases of giant meningiomas associated to vascular malformations and we discuss the pertinent literature. Case Descriptions: In the first case: A large right temporal meningioma with erosion of the sphenoid greater wing and extension toward infratemporal fossa and right orbit - a large pseudoaneurysm of right middle cerebral artery branch was found end embolized during DSA. In the second case: A giant parieto-temporal meningioma - DSA permitted the full visualization of an abnormal drainage of superior sagittal sinus like a "sinus pericranii" that was respected during the following surgery. Conclusion: We think that MRI angiography is the exam of choice to study vascular anatomy in meningiomas. Nonetheless, DSA remains a useful tool in giant meningiomas not only to embolizate the lesion but also to treat tumor associated vascular malformation and to achieve the full knowledge of vascular anatomy. We think that a wide communication between interventionalist and surgeon is essential for the optimal management of these patients.

  6. Evaluation of fast highly undersampled contrast-enhanced MR angiography (sparse CE-MRA) in intracranial applications - initial study.

    Science.gov (United States)

    Gratz, Marcel; Schlamann, Marc; Goericke, Sophia; Maderwald, Stefan; Quick, Harald H

    2017-03-01

    To assess the image quality of sparsely sampled contrast-enhanced MR angiography (sparse CE-MRA) providing high spatial resolution and whole-head coverage. Twenty-three patients scheduled for contrast-enhanced MR imaging of the head, (N = 19 with intracranial pathologies, N = 9 with vascular diseases), were included. Sparse CE-MRA at 3 Tesla was conducted using a single dose of contrast agent. Two neuroradiologists independently evaluated the data regarding vascular visibility and diagnostic value of overall 24 parameters and vascular segments on a 5-point ordinary scale (5 = very good, 1 = insufficient vascular visibility). Contrast bolus timing and the resulting arterio-venous overlap was also evaluated. Where available (N = 9), sparse CE-MRA was compared to intracranial Time-of-Flight MRA. The overall rating across all patients for sparse CE-MRA was 3.50 ± 1.07. Direct influence of the contrast bolus timing on the resulting image quality was observed. Overall mean vascular visibility and image quality across different features was rated good to intermediate (3.56 ± 0.95). The average performance of intracranial Time-of-Flight was rated 3.84 ± 0.87 across all patients and 3.54 ± 0.62 across all features. Sparse CE-MRA provides high-quality 3D MRA with high spatial resolution and whole-head coverage within short acquisition time. Accurate contrast bolus timing is mandatory. • Sparse CE-MRA enables fast vascular imaging with full brain coverage. • Volumes with sub-millimetre resolution can be acquired within 10 seconds. • Reader's ratings are good to intermediate and dependent on contrast bolus timing. • The method provides an excellent overview and allows screening for vascular pathologies.

  7. Computed tomographic angiography study of the relationship between the lingual artery and lingual markers in patients with obstructive sleep apnoea

    Ener