ISMRM 24th Annual Meeting & Exhibition • 07-13 May 2016 • Singapore

Scientific Session: Atherosclerosis Imaging

Thursday, May 12, 2016
Summit 1
13:30 - 15:30
Moderator: Winfried Willinek

High resolution 3D diffusion imaging of carotid vessel wall using stimulated echo based diffusion prepared turbo spin echo sequence
Qinwei Zhang1, Barbara Cervantes2, Dimitrios C. Karampinos2, Bram F. Coolen1, Aart J. Nederveen1, and Gustav J. Strijkers3
1Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands, 2Department of Diagnostic and Interventional Radiology, Technische Universität München, Munich, Germany, 3Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
 Diffusion imaging is becoming a promising alternative to contrast enhanced imaging in detecting lipid core and hemorrhage in atherosclerotic plaques. Diffusion prepared turbo spin echo sequence (DP-TSE) has been proven to be feasible to acquire 3D diffusion images of carotid vessel wall, but it has critical requirement on the eddy currents. This study demonstrates that using stimulated echo based DP-TSE sequence, together with m1 nulling diffusion gradients, and MLEV refocusing RF pulses, high resolution 3D carotid vessel wall diffusion imaging can be achieved in the presence of eddy current, motion and B1-inhomogeneity.

DCE-MRI reveals more extensive vasa vasorum in patients with cardiovascular events
Huijun Chen1, Juan Wang2, Jie Sun3, Daniel S Hippe3, Xihai Zhao1, and Hongbing Liu2
1Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China, People's Republic of, 2Cardiology, People’s Liberation Army General Hospital, Beijing, China, People's Republic of, 3Radiology, University of Washington, Seattle, WA, United States
Pharmacokinetic modeling of DCE-MRI  can quantify the adventitial vasa vasorum of carotid atherosclerotic lesions using the transfer constant (Ktrans). However, the relationship between the DCE-MRI quantified carotid adventitial vasa vasorum  and cardiovascular events remains unclear. In this study, we found that the adventitial Ktrans of carotid artery measured by DCE-MRI was associated with cardiovascular events (cerebral ischemic events and coronary artery events), suggesting that the carotid adventitial vasa vasorum is not merely a local risk factor but also a promising systemic marker for cardiovascular risk. DCE-MRI may be valuable for identifying high risk patients in clinical practice.

Texture-Based Classification of Advanced Carotid Atherosclerotic Lesions on Multi-contrast Black-blood MRI at 3.0 Tesla: A Pilot Study
Huilin Zhao1, Shiteng Suo1, Peipei Hao1, Xiaosheng Liu1, Xihai Zhao2, Yongming Dai3, Chun Yuan4, and Jianrong Xu1
1Radiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, People's Republic of, 2Center for Biomedical Imaging Research, Tsinghua University School of Medicine, Beijing, China, People's Republic of, 3Philips Healthcare, Shanghai, China, People's Republic of, 4Radiology, University of Washington, Seattle, WA, United States
Texture analysis with the combined set of texture features may be useful in discriminating vulnerable plaque. This study sought to determine the feasibility of texture analysis for the classification of American Heart Association (AHA) type IV-V and type VI carotid atherosclerotic lesions at multi-contrast black-blood MR images. Our results suggest that texture-based classification of type IV-V and type VI lesions is feasible on precontrast T1-weighted images. This preliminary evaluation indicates that carotid plaque texture analysis is a potentially useful adjunct tool for quantitative evaluation of atherosclerotic plaque vulnerability.

3D Carotid Wall Imaging: Stack-of-stars Trajectory for Multi-contrast Atherosclerosis Characterization (STAR-MATCH)
Xiaoming Bi1, Zhaoyang Fan2, Yutaka Natsuaki1, Debiao Li2, and Gerhard Laub1
1Siemens Healthcare, Los Angeles, CA, United States, 2Cedars-Sinai Medical Center, Los Angeles, CA, United States
The recently developed MATCH technique integrates multiple 3D image sets into a single measurement and it is a promising method for carotid plaque characterization. One of the remaining challenges is the gross motion of carotid arteries that originates from pulsation, breathing and swallowing. In this work, a motion robust stack-of-stars sampling trajectory was implemented into the MATCH sequence (STAR-MATCH). Preliminary studies from volunteers and patient demonstrate it is feasible to characterize carotid plaque using the STAR-MATCH sequence with improve motion robustness.

Coronary Atherosclerosis T1-weighed Characterization with Integrated Anatomical Reference (CATCH): Comparison with High-risk Plaque Features on OCT
Yibin Xie1, Young-Jin Kim2, Jianing Pang1, Qi Yang1, Jung-Sun Kim3, Christopher T. Nguyen1, Zixin Deng1, Byoung Wook Choi2, Zhaoyang Fan1, Daniel S. Berman1, Hyuk-Jae Chang3, and Debiao Li1
1Cedars-Sinai Medical Center, Los Angeles, CA, United States, 2Department of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea, Republic of, 3Division of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, Korea, Republic of
The aim of this work is to investigate the nature of pre-contrast and post-contrast T1w plaque hyper-intensity by comparing with coronary plaque morphology assessed by intracoronary optical coherence tomography (OCT). We scanned 13 healthy subjects and 30 stable angina patients using our recently developed whole-heart T1w coronary plaque characterization framework (CATCH). Compared with the classification based on OCT, we found that pre-contrast plaque to myocardial ratio (PMR) was significantly higher in the presence of large lipids, macrophages, and cholesterol crystals, whereas post-contrast PMR was significantly higher in the presence of macrophages and microvessels. 

Increased Coronary Vessel Wall Thickness in Hyper IgE Syndrome Patients; Depiction by Magnetic Resonance Vessel Wall Imaging and Pathological Correction - Permission Withheld
Khaled Z. Abd-Elmoniem1, Nadine Z. Ramos1, Saami Yazdani2, Ahmed M. Ghanem1,3, Steven M. Holland4, Alexandra F. Freeman4, and Ahmed M Gharib1
1Biomedical and Metabolic Imaging Branch, NIDDK, Bethesda, MD, United States, 2University of Southern Alabama, Mobile, AL, United States, 3Electrical Engineering, Suez Canal University, Ismailia, Egypt,4NIAID, Bethesda, MD, United States
In this study, coronary wall MRI is used to assess the coronary wall thickness of patients with autosomal dominant hyper-IgE (AD-HIES) or Job's syndrome; a primary immunodeficiency caused by mutations in STAT3. Supported by post-mortem histology, MRI coronary wall of AD-HIES patients was thicker than in healthy subjects but comparable to CAD patients. These findings suggest that coronary arteries in Job’s syndrome are affected with atherosclerosis, contrary to prior beliefs and study findings. Direct histologic evaluation confirms the presence of atherosclerosis with lack of needed supportive adventitial thickening and elastic components. These findings suggest mechanisms for weakened vessel wall that may lead to coronary dilation and aneurysm in AD-HIES.

Evaluation of endothelial barrier function in atherosclerosis induced rabbits using S-nitroso human serum albumin (S-NO-HSA) - blood pool agent compound and dynamic contrast-enhanced (DCE)-MRI
Peter Opriessnig1, Gunter Almer1, Harald Froehlich1, Claudia Cabella2, Rudolf Stollberger3, Seth Hallstroem4, Gerd Hoerl4, and Harald Mangge1
1Clinical Institute for Medical and Chemical Laboratory Diagnosis, Medical University of Graz, Graz, Austria, 2CRB Bracco Imaging SpA, Colleretto Giacosa, Torino, Italy, 3Institute of Medical Engineering, Graz University of Technology, Graz, Austria, 4Institute of Physiological Chemistry, Medical University of Graz, Graz, Austria
Endothelial dysfunction plays a key role in the progression and pathogenesis of atherosclerosis (AS). DCE-MRI in combination with a special nitric oxide donor S-nitroso human serum albumin (S-NO-HAS) blood pool agent (B22956/1) compound could be an additional measure that provides information on the influence of plaque burden on the vascular permeability and vasomotion. In this work, we demonstrate the feasibility to investigate endothelial barrier function and NO induced endothelium-independent vasomotor response of the abdominal aorta in control and AS induced rabbits simultaneously. Relative vessel wall signal enhancement and change in lumen area were measured using a double-inversion-recovery turbo-spin-echo sequence.

Impact of exercise intervention on vascular function in PAD
Erin K Englund1, Michael C Langham2, Thomas F Floyd3, Felix W Wehrli2, and Emile R Mohler4
1Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, 2Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, 3Department of Anesthesiology, Stony Brook University, Stony Brook, NY, United States, 4Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States
Peripheral vascular function can be interrogated by measuring recovery dynamics following induced ischemia. In this study, 136 patients with peripheral artery disease were randomized into supervised exercise rehabilitation (SER) or standard medical care (SMC). Each patient’s leg was scanned before and after the intervention period. MRI data were acquired throughout an ischemia-reperfusion paradigm with PIVOT, a method to simultaneously and dynamically measure perfusion, venous oxygen saturation, and skeletal muscle T2*. Patients randomized to SER had a significant increase in peak perfusion from baseline to follow-up when averaged across the entire cross-section of the leg and in the peroneus muscle. 

MRI biomarkers associated with guide wire puncture forces required to cross ex-vivo human peripheral arterial chronic total occlusions
Trisha Roy1,2, Garry Liu1, Noor Shaikh1, Kevan Anderson1, Nicolas Yak1, Xiuling Qi1, Andrew Dueck1,2, and Graham Wright1,3
1Schulich Heart Program and the Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 2Division of Vascular Surgery, University of Toronto, Toronto, Canada, 3Department of Medical Biophysics, University of Toronto, Toronto, Canada
Percutaneous vascular interventions (PVI) for treating peripheral arterial disease (PAD) have poor outcomes with high re-intervention and failure rates. Not all lesions are amenable to PVI, but predicting failure is difficult. While CT can identify heavily calcified lesions, current imaging offers limited differentiation between hard and soft PAD plaques, which impacts procedural success. This study demonstrates the feasibility of using MRI biomarkers to characterize plaque components in ex-vivo human peripheral arteries with histologic and microCT validation. We demonstrate that significantly higher puncture forces are required to cross non-calcified “hard” chronic total occlusions (CTOs) compared to “soft” CTOs, as classified by these MRI biomarkers.

Optimization of 3 dimensional (3D), high resolution T2 weighted SPACE  for carotid vessel wall imaging on a 7T whole-body clinical scanner
Claudia Calcagno1,2, Bram Coolen3, Bei Zhang1,2, Gilles Boeykens 3, Philip Robson1,2, Venkatesh Mani1,2, Aart J Nederveen3, Willem Mulder1,2, and Zahi Fayad1,2
1Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 2Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 3Department of Radiology, Academisch Medisch Centrum, Amsterdam, Netherlands
Accurate morphological measurements and classification of carotid plaques require imaging with high spatial resolution, and may benefit from the increased signal intrinsically available on ultra-high field (7T) magnets.  Several studies have already investigated carotid vessel wall imaging at 7T and compared it with state-of-the-art 3T protocols. These initial investigations have focused on 2 dimensional (2D), multi-slice imaging. Better than this approach, 3 dimensional (3D) vessel wall imaging allows characterizing extensive vascular territories while minimizing partial volume artifacts in plaque-prone regions, such as the carotid bulb and bifurcation. Here, we demonstrated the feasibility of performing 3D carotid vessel wall imaging on a whole body 7T clinical magnet using a custom made carotid coil. 

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