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

描述（由申请人提供）：已知通过大脑中动脉（MCA）供应大脑的大动脉中的动脉粥样硬化斑块引起的血栓栓塞现象占缺血性MCA卒中的四分之一到三分之一，尽管这是卒中最可治疗的原因之一。除了管腔狭窄测量，检测导致血栓栓塞的高风险动脉粥样硬化斑块不是常规卒中检查的一部分。目前的斑块磁共振成像（MRI）协议，虽然有效，但受到扫描时间长，覆盖范围小和依赖钆对比度的限制。将斑块MRI转化为临床需要使用临床可用的线圈对高风险斑块特征进行快速、大覆盖范围、非造影剂检测。我们的目标是开发一种时间效率高的MRI筛查方法，用于检测MCA供血区的高风险动脉粥样硬化病变。为了实现这一点，我们将开发MRI序列，以特异性识别与神经系统症状发展相关的三种主要生物标志物：1）斑块内出血和血栓，2）大的富含脂质的坏死核心和3）破坏的管腔表面。这些序列将被优化用于快速筛查从主动脉弓到颅底的整个颈动脉。方案性能将在计划进行颈动脉内膜切除术的患者中根据组织学进行确认。然后，将使用经确认的方案来检验以下假设：MCA区域中非腔隙性或心脏源性的缺血性卒中与MRI可见的高风险病变相关。通过证明有症状一侧的高危病变数量显著高于对侧，我们旨在确立筛查高危斑块的重要性。我们的研究将有助于确定大动脉疾病引起的卒中中高危斑块的患病率，并证明在临床环境中进行非造影剂斑块筛查的可行性。高危斑块成像的临床应用可能会改善大动脉粥样硬化卒中患者的治疗选择。

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.