MRI IDENTIFICATION--HIGH RISK ATHEROSCLEROTIC PLAQUES

由于动脉粥样硬化引起的心血管疾病仍然是主要原因 死亡在美国。 临床症状和发病率， 动脉粥样硬化疾病的结果是由于斑块的不稳定性， 表现为溃疡、血栓形成和/或斑块内出血。 许多研究都致力于了解动脉粥样硬化的形成， 疾病的进展和导致心脏病的最终事件 攻击或中风。然而，人们对如何 非侵入性地识别体内高风险病变，并监测 病变纵向进展。 该提案提出了一项计划， 测量MR图像中的动脉粥样硬化斑块体积，并评估 MRI在检测相关斑块特征方面的能力 临床症状。 我们的研究集中在晚期病变， 颈动脉分叉，由于1）与卒中密切相关，2） 它们通过高分辨率MRI技术的可及性，以及3） 由于颈动脉内膜切除术， 为我们提供了一个很好的机会来验证MRI结果， 对样本进行组织学检查。 该项目的长期目标是使用高分辨率MRI， 血流动力学显著（大于70%）的患者 直径减小）颈动脉狭窄，以区分那些斑块， 将导致血栓形成/栓塞和卒中的发生。 在 目前还没有可靠的方法来测量斑块体积 或评估体内斑块的特征。 的 具体目的是：1）测试体内MRI是否可用于测量 动脉粥样硬化体积，以及2）测试体内MRI是否可以 识别具有薄纤维帽和坏死核心的病变。我们提出 以确定MRI斑块体积测量的准确性， MRI对不同类型肿瘤检出的敏感性和特异性 的病变。 不同斑块类型的准确诊断具有特定的 临床相关性，作为覆盖坏死核心的弱化纤维帽 被认为是结构脆弱的，可能先于斑块事件 破裂和血栓栓塞性闭塞，在颈动脉中， 导致中风。 能够准确测量斑块体积， 以区分晚期病变的结构特征， 体内动脉粥样硬化可能提供一种非侵入性机制， 斑块进展的演变，并检测可能使 个体发生临床事件的风险更大。

Cardiovascular disease due to atherosclerosis remains the leading cause of death in the United States. Clinical symptoms and morbidity that result from atherosclerotic disease are due to plaque instability and are manifested as ulceration, thrombosis and/or intraplaque hemorrhage. Much research has been directed at understanding the atherogenesis, the progression of the disease and the final events that lead to heart attack or stroke. However, relatively little is known about how to identify high risk lesions in vivo noninvasively and to monitor the lesion progression longitudinally. This proposal presents a plan to measure the atherosclerotic plaque volume in MR images and to assess the power of MRI in detecting plaque characteristics that are associated with clinical symptoms. We focus our study on advanced lesions at the carotid bifurcation due to 1) their close association to stroke, 2) their accessibility by high resolution MRI techniques, and 3) the accessibility of carotid samples due to carotid endarterectomy that provides us with excellent opportunity to verify the MRI results by examining the samples histologically. The long term goal of this project is to use high resolution MRI in patients with hemodynamically significant (greater than 70 percent diameter reduction) carotid stenoses to differentiate those plaques that will lead to the development of thrombosis/embolization and stroke. At present there are no reliable means to either measure the plaque volume in vivo or to assess the characteristics of plaques in vivo. The specific aims are: 1) to test whether in vivo MRI can be used to measure the atherosclerotic volume, and 2) to test whether in vivo MRI can identify lesions with thin fibrous cap and a necrotic core. We propose to determine the accuracy of MRI plaque volume measurement and the sensitivity and specificity of MRI in the detection of different types of lesions. Accurate diagnosis of different plaque types has particular clinical relevance, as a weakened fibrous cap covering a necrotic core is thought to be structually weak, and may precede the events of plaque rupture and thromboembolic occlusion, which in the carotid artery may result in stroke. The ability to accurately measure plaque volumes and to distinguish the structural characteristics of advanced lesions of atherosclerosis in vivo may provide a noninvasive mechanism to follow the evolution of plaque progression and to detect lesions that may put individuals at greater risk of clinical events.