Middle cerebral artery stroke: Non-contrast MR screening of high-risk plaque

描述（由申请人提供）：在通过大脑中动脉（MCA）供应大脑的大动脉中，由动脉粥样硬化斑块引起的血栓栓塞现象已知占缺血性MCA中风的四分之一到三分之一，尽管它是中风最可治疗的原因之一。除了管腔狭窄测量外，检测动脉粥样硬化斑块对血栓栓塞的高风险，并不是常规卒中检查的一部分。目前的斑块磁共振成像（MRI）方案虽然有效，但受扫描时间长、覆盖范围小和依赖钆造影剂的限制。将斑块MRI应用于临床需要使用临床可用的线圈快速、大范围、非对比检测高风险斑块特征。我们的目标是开发高效的MRI筛查，以检测MCA提供的区域的高危动脉粥样硬化病变。为了实现这一目标，我们将开发MRI序列来明确识别与神经系统症状发展相关的三个主要生物标志物：1)斑块内出血和血栓，2)富含脂质的大坏死核心和3)管腔表面破坏。这些序列将被优化以快速筛选从主动脉弓到颅底的整个颈动脉。方案的执行将根据计划进行颈动脉内膜切除术的患者的组织学进行验证。经过验证的方案将用于验证假设，即在非腔隙性或心脏起源的MCA区域的缺血性中风与MRI可见的高风险病变相关。通过证明症状侧的高风险病变数量明显高于对侧，我们的目标是建立筛查高风险斑块的重要性。我们的研究将有助于确定由大动脉疾病引起的卒中中高危斑块的患病率，并证明非对比剂斑块筛查在临床环境中的可行性。高风险斑块成像的临床应用可以改善卒中合并大动脉粥样硬化患者的治疗选择。

DESCRIPTION (provided by applicant): Thromboembolic phenomena arising from atherosclerotic plaque in large arteries supplying the brain through the Middle Cerebral Artery (MCA) are known to account for a quarter to one-third of ischemic MCA stroke despite being one of the most treatable causes of stroke. Beyond luminal stenosis measurement, detection of atherosclerotic plaque at high-risk for causing thromboembolism, is not a part of routine stroke workup. Current plaque Magnetic Resonance Imaging (MRI) protocols, though effective, are limited by long scan times, small coverage and dependence on gadolinium contrast. Translation of plaque MRI to the clinic requires fast, large coverage, non-contrast detection of high-risk plaque features using clinically available coils. Our objective is to develop time-efficient MRI screening for detection of high-risk atherosclerotic lesions in the region supplied by the MCA. To accomplish this we will develop MRI sequences to specifically identify the three main biomarkers linked with the development of neurological symptoms: 1) intra-plaque hemorrhage and thrombus, 2) large lipid-rich necrotic core and 3) disrupted luminal surface. These sequences will be optimized for fast screening of the entire carotid artery from the arch of aorta to the base of the skull. Protocol performance will be validated against histology in patients scheduled for carotid endarterectomy. The validated protocol will then be used to test the hypothesis that ischemic stroke in the MCA territory that is not lacunar or cardiac-origin is associated with an MRI visible high-risk lesion. By demonstrating a significantly higher number of high-risk lesions on the symptomatic side than the contra-lateral side, we aim to establish the importance of screening for high-risk plaque. Our study will help to establish the prevalence of high-risk plaque in stroke attributable to large-artery disease and demonstrate the feasibility of non-contrast plaque screening in the clinical setting. Clinical use of high-risk plaque imaging may improve treatment options for stroke patients with large-artery atherosclerosis. PUBLIC HEALTH RELEVANCE: One of the major causes of stroke, the third leading cause of death in the US, is atherosclerosis of the major arteries supplying blood to the brain. Despite research advances in this area, atherosclerotic plaques at high-risk for causing stroke are not screened for in clinical stroke imaging centers. A clinically applicable imaging method for identifying high-risk plaque is developed in this proposal which, will guide clinical decision making and improve treatment strategies for these stroke patients.