High-Resolution 3-Tesla-MRI of the Carotid Arteries in the Evaluation of Cryptogenic Stroke

大约70%的缺血性中风是由心脏栓塞、小血管疾病或大动脉粥样硬化引起的。尽管进行了广泛的检查，但高达25%的病例病因不明（隐源性卒中）。然而，只有当存在明显狭窄时，颈动脉血管中的动脉粥样硬化斑块才被认为是病因（例如>50%；toast分类系统）。从病理生理学的观点来看，这种分类似乎有问题。然而，常规应用成像方法的技术局限性限制了对血管壁非狭窄性动脉粥样硬化变化的详细分析和易损斑块（VP）的识别。颈动脉血管的高分辨率MRI是一种相对新颖的非侵入性方法，可以识别VP，与组织病理学有很好的相关性。基于我们课题组之前的研究表明，VP与缺血性卒中之间存在实质性的相关性，我们启动了一项前瞻性、多中心的急性卒中颈动脉斑块成像（CAPIAS）研究。本研究的目的是探讨VP在隐源性脑卒中患者中的患病率，以及VP的存在是否对临床表现或无症状脑卒中的复发率以及对血管壁动脉粥样硬化改变的进展有影响。卒中对侧血管和一组已知卒中病因的患者作为对照。该提案旨在获得一笔研究资助，以支持/实现对颈动脉和神经头盖骨的MRI数据的有效分析，这些数据在capias研究期间已经获得并仍在获得（基线和12个月的随访）。颈动脉的图像数据将使用专用的软件算法进行评估。根据aha分类系统和血管壁的定量参数和单一斑块成分（如斑块内出血、富脂/坏死核心、钙化）来表征动脉粥样硬化病变。基于这些数据，我们评估了VP与隐源性卒中、VP与卒中复发以及VP对动脉粥样硬化进展的影响之间的相关性。此外，专业数据库的建立将确保评估表型数据的长期有效可用性。

Approximately 70% of ischemic strokes are caused by cardioembolism, small vessel disease or large artery atherosclerosis. Despite extensive workup the etiology remains unknown in up to 25% of cases (cryptogenic stroke). However, atherosclerotic plaques in the carotid vessels are only considered as causative if significant stenosis is present (e.g. >50%; TOAST-classification system). From a pathophysiological viewpoint this classification may seem questionable. Technical limitations of routinely applied imaging methods however limit the elaborate analysis of non-stenosing atherosclerotic changes of the vessel wall and the identification of vulnerable plaque (VP). High-resolution MRI of the carotid vessels is a relatively novel non-invasive approach, allowing for identification of VP with good correlation to histopathology. Based on previous work of our study group which suggests a substantial correlation between VP and ischemic stroke, the prospective, multicenter Carotid Plaque Imaging in Acute Stroke (CAPIAS)-study was initiated. Objectives of the study are to examine the prevalence of VP in patients with cryptogenic stroke and whether the presence of VP has influence on the recurrence rate of clinical manifest or silent stroke as well as on the progression of atherosclerotic changes in the vessel wall. Vessels contralateral to stroke and a group of patients with known stroke etiologies serve as controls. This Proposal is aimed at a research grant to support/enable an efficient analysis of MRI data of the carotid arteries as well as of the neurocranium which has already been and is still being acquired during the CAPIAS-study (at baseline and 12 month follow-up). Image data of the carotids is going to be evaluated using dedicated software algorithms. Atherosclerotic lesions are characterized according to the AHA-classification system and quantitative parameters of the vessel wall and singular plaque components (e.g. intraplaque hemorrhage, lipid-rich/necrotic core, calcifications) are obtained. Based on this data correlations between presence of VP and cryptogenic stroke, VP and stroke recurrence, and the effect of VP on progression of atherosclerosis are evaluated. Furthermore the establishment of a professional data base is going to ensure the long-term and effective availability of the assessed phenotypical data.