Atherosclerosis, Coronary & Vessel Wall Imaging
Thursday 6 May 2010
Room A8 16:00-18:00 Moderators: Suzanne C. Gerretsen and Yi Wang

16:00 661. 

Diagnostic Performance of Non-Contrast Whole-Heart Coronary Magnetic Resonance Angiography Combined with Black-Blood Arterial Wall Imaging in Patients with Suspected Coronary Artery Disease
Qinyi Dai1, Zhaoqi Zhang1, Yi He1, Wei Yu1, Biao Lu1, Zhanming Fan1, Jing An2, Lixin Jin3, Renate Jerecic3, Guobin Li4, Wolfgang Rehwald5, Debiao Li6
1Radiology, AnZhen hospital, Beijing, China; 2Siemens Mindit Magnetic Resonance, Siemens Healthcare, MR Collaboration NE Asia; 3Siemens Limited China, Siemens Healthcare, MR Collaboration NE Asia; 4Siemens Mindit Magnetic Resonance Ltd.; 5Siemens Healthcare USA; 6Northwestern University, Chicago, USA

The combined Whole-heart coronary MRA and black-blood-coronary-wall-imaging hasn't been reported to detect CAD yet. Continuous slices for wall imaging of 48 segments were positioned along the suspected lesions of WH CMRA. A positive diagnosis of CAD was made when stenosis ¡Ý50% at least one of the techniques.  15/48 segments were diagnosed as CAD by x-ray angiography. The sensitivities of WH CMRA only and both techniques were (12/15) and (14/15), NPVs were (33/36) and (33/34), respectively. There was no difference in specificity or PPV. The combination of two techniques improves the diagnostic accuracy to detect CAD over WH CMRA alone.

16:12 662. 

Contrast-Enhanced Whole-Heart Coronary MRA in 5 Minutes Using Radial EPI
Himanshu Bhat1, Qi Yang2, Sven Zuehlsdorff3, Debiao Li1
Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, United States; 2Radiology, Capital Medical University, Xuanwu Hospital, Beijing, China; 3Siemens Medical Solutions USA, Inc., Chicago, IL, United States

Whole-heart coronary MRA is challenging due to the long data acquisition time on the order of 8-12 minutes. The purpose of this work was to optimize a radial EPI technique for contrast-enhanced whole-heart coronary MRA, with the goal of combining the scan efficiency of EPI with the motion insensitivity of radial sampling.

16:24 663. 

MRI Assessment of Endothelial Damage and Angiogenesis in Porcine Coronary Arteries Using Gadofosveset
Steen Fjord Pedersen1, William P. Paaske2, Troels Thiem3, Steffen Ringgaard4, Samuel A Thrysøe4, Won Yong Kim5
Aarhus University Hospital, Aarhus, Denmark; 2Dept. of Cardiothoracic and Vascular Surgery T, Aarhus University Hospital, Skejby, Denmark; 3Dept. of Cardiology, Aarhus University Hospital, Skejby, Denmark; 4MR-center, Aarhus University Hospital, Skejby, Denmark; 5Dept. of Cardiology, and MR-center, Aarhus University Hospital, Skejby, Denmark

Endothelial damage and angiogenesis are essential in atherosclerotic plaque development and destabilization .We sought to examine whether contrast enhanced MRI using gadofosveset would enable the detection of endothelial damage and neovessels in balloon injured porcine coronary arteries. MRI showed contrast enhancement of the injured vs. the non-injured control artery with a significant increase in the diameter of  (30±19 % versus 4±8%; P=0.01). Ex-vivo coronary vessel wall MRI contrast enhancement was in agreement with extravasated Evans blue with a kappa value of 0.64 (p<0.001). and there was a linear correlation between coronary MRI contrast-enhancement and microvessel density (r=0.78, p<0.001).

16:36 664.  

Assessment of Coronary Endothelial Dysfunction in Young Healthy Smokers Using 3T Phase Contrast Cine MRI and Cold Pressor Test
Shingo Kato1, Hajime Sakuma1, Kakuya Kitagawa1, Motonori Nagata1, Yeonyee E. Yoon1, Shinichi Takase1
Department of Radiology, Mie University Hospital, Tsu, Mie, Japan

Blood flow volumes in the LAD artery and in coronary sinus (CS) at rest and during cold pressor test were quantified in 10 young non-smokers and 6 age-matched smokers using 3T MR imager. Coronary flow was significantly augmented during CPT in non-smokers (LAD: 28.5 ± 6.8mL/min to 36.5 ± 7.3mL/min, p=0.017). However, the CPT/rest coronary flow ratio was significantly reduced in smokers when compared with non-smokers (0.86 ± 0.26 vs 1.33 ± 0.38, p=0.02). CPT test using 3T MR imager allows for non-invasive assessment of coronary endothelial dysfunction.

16:48 665.

Reproducible Coronary Vessel Wall Imaging at 3T Using Improved Motion Sensitized Driven Equilibrium (IMSDE)
Suzanne Gerretsen1, Jinnan Wang2,3, Jeffrey H. Maki3, Caroline Jaarsma1, Daniel Herzka4, Boacheng Chu3, Vasily V. Yarnykh3, Chun Yuan3, Tim V. Leiner1

1Radiology, Maastricht University Medical Center, Maastricht, Netherlands; 2Clinical Sites Research Program, Philips Research North America, Seattle, WA, United States; 3Radiology, University of Washington, Seattle, WA, United States; 4School of Medicine, Johns Hopkins University, Baltimore, MD, United States

This study investigated the reproducibility of the recently developed improved Motion Sensitized Driven Equilibrium (iMSDE) technique for MR imaging of the coronary vessel wall at 3T. 19 volunteers underwent MRI of the right coronary artery lumen and vessel wall twice. Lumen diameter and vesselwall thickness measurements were performed, and measurements of the two scanning sessions were compared. In 15/19 volunteers two measurements of both coronary lumen and vessel wall were acquired successfully. This study demonstrated that iMSDE is able to visualize the coronary vessel wall of healthy volunteers at 3T with good reproducibility of lumen diameter and wall thickness measurements.

17:00 666

Correlation of Atherosclerotic Plaque Compositions in Coronary and Carotid Arteries - not available
Qian Zhao1, Xihai Zhao2, Jianming Cai3, Feiyu Li2, Jianli Yang1, Chun Yuan2, Zulong Cai3
1Radiology, The General Hospital of Beijing Military Area Command of  People's Liberation Army, Beijing, China; 2Radiology, University of Washington, Seattle, WA, United States; 3Radiology, The General Hospital of Chinese PLA, Beijing, China

Atherosclerosis has been shown to be a systematic disease which often involves multiple arterial vascular beds. Recently, a number of studies demonstrated that there is a significant correlation between coronary and carotid atherosclerosis. This study sought to evaluate the association between coronary and carotid plaque compositions. Our results showed coronary plaque types significantly associating with carotid plaque compositions. In particular, coronary mixed plaque might be may be effective classifiers of carotid plaque compositions, especially for carotid IPH.

17:12 667

Wall Shear Stress as a Stimulus for Intra-Plaque Hemorrhage in Carotid Atherosclerotic Plaque: An MRI-Based CFD Pilot Study
Gador Canton1, Huijun Chen1, Minako Oikawa2, Hunter R. Underhill1, Wei Yu3, Thomas S. Hatsukami4, Chun Yuan1, William Sean Kerwin

1Radiology, University of Washington, Seattle, WA, United States; 2Cardiovascular Medicine, Tohoku University, Sendai, Japan; 3Radiology, Beijing Anzhen Hospital, Beijing; 4Surgery, University of Washington, Seattle, WA, United States

The aim of this study was to explore the hypothesis that intra-plaque hemorrhage, a feature associated with adverse outcomes and atherosclerotic plaque progression, is more likely to occur in plaques with elevated levels of wall shear stress (WSS). We used multi-sequence MRI to characterize seven human carotid atherosclerotic plaques and an MRI-based computational fluid dynamics (CFD) model to solve the equations governing the blood flow. The results from this pilot study indicate a possible link between the presence of hemorrhage within a lipid-rich necrotic core in human carotid atherosclerotic plaques and the shear stress force acting on the luminal surface.

17:24 668

Identification of Lipid Deposits and Quantification of Carotid Endarterectomy Plaque Components Using High Resolution MRI and Image-Guided Proton MRS at 11.7T
Haiying Tang1, Vladimir Reiser1, Zhi-Qiang Zhang1, Ting-Chuan Wang1, Suzanne S. Eveland1, Zhu Chen1, Ben T. Chen1, Edward A. O'Neill1, Michael Klimas1
Merck Research Laboratories, Rahway, NJ, United States

Patients with carotid plaque undergo endarterectomy based on empirical guidelines, primarily the magnitude of stenosis. Patients who would derive benefit from carotid endarterectomy are those with lipid rich, vulnerable plaque at high risk of rupture. We hypothesis that non-invasive MRI technique can provide distinguishable signal features of plaque components such as fibrous tissue, lipid-rich necrotic core, intra-plaque hemorrhages, and calcifications, therefore can help identify at-risk patients preoperatively. The purpose of this study is to demonstrate the capability of MRI and MRS methods for characterizing plaque composition and quantifying lipid deposition, thereby facilitating development of noninvasive, quantitative predictor of plaque stability.

17:36 669.

3D Projection Reconstruction Based Respiratory Motion Correction Technique for Free-Breathing Coronary MRA
Himanshu Bhat1, Lan Ge1, Sonia Nielles-Vallespin2, Sven Zuehlsdorff3, Debiao Li1
Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, United States; 2Cardiovascular MR Unit, Royal Brompton And Harefield NHS Foundation Trust, London, United Kingdom; 3Siemens Medical Solutions USA, Inc., Chicago, IL, United States

Current navigator based free-breathing coronary MRA techniques measure the position of the diaphragm and use a fixed correlation factor to estimate the position of the heart. Such techniques suffer from errors due to the indirect estimation of heart position and are plagued by low scan efficiencies (typically between 30 and 50 %). The purpose of this work was to develop a 3D projection reconstruction (3D PR) based coronary MRA technique which accepts all the data during the scan, irrespective of respiratory position, and retrospectively corrects for respiratory motion by using 3D image registration.

17:48 670

Multimodality Imaging of Carotid Artery Plaques: 18F-FDG PET, CT, and MRI
Robert Kwee1, Gerrit Teule, Robert van Oostenbrugge, Werner Mess, Martin Prins, Rob van der Geest2, Paul Hofman, Jos van Engelshoven, Joachim Wildberger, Eline Kooi
1Maastricht University Medical Center, Maastricht, Limburg, Netherlands; 2Leiden University Medical Center, Leiden, The Netherlands

The present study demonstrated that overall correlations between 18F-FDG PET findings and morphological and compositional CT/MRI findings of carotid plaques are weak. Correlations between CT and MRI findings are moderate-to-strong, but measurements of lipid-rich necrotic core and calcifications are significantly larger at CT, whereas measurements of fibrous tissue are significantly larger at MRI. There is also considerable variation in absolute differences between CT and MRI measurements, implying that CT and MRI are not interchangeable. Future prospective longitudinal studies should determine which imaging modality is most effective for risk stratifying patients for stroke.



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