Coronary Atherosclerosis Evaluation by Arterial Wall MRI

描述（由申请人提供）：冠状动脉粥样硬化程度的直接和无创可视化是评估冠心病的主要目标。冠状动脉钙化和颈动脉内膜中层厚度是冠状动脉粥样硬化的替代标志物的实例，其试图非侵入性地定义冠状动脉疾病存在的程度。特别是冠状动脉钙是冠状动脉粥样硬化负荷的标志物，但它是总斑块的次要成分，不存在于早期斑块中。冠状动脉壁MRI是一种直接测量冠状动脉壁厚度的新方法，并且是唯一现有的无电离辐射的无创测试，可以直接询问冠状动脉血管并在此早期阶段提供疾病负担的测量。先前的研究表明，当冠状动脉腔没有狭窄或狭窄程度很小时，MRI可检测到冠状动脉壁厚度增加。因此，本研究建议使用MRI评估冠状动脉壁厚度作为早期动脉粥样硬化疾病的测量值的作用，以及2）确定冠状动脉壁厚度与动脉粥样硬化的已知风险和其他非侵入性替代标志物的关系。本研究将在多种族动脉粥样硬化研究（梅萨）的背景下进行，MESA是一项NHBLI前瞻性研究，纳入了6814例无临床表现动脉粥样硬化疾病的受试者。梅萨研究的基本假设是，从危险因素到临床疾病的途径是通过亚临床疾病的发展。梅萨队列在动脉粥样硬化疾病的传统危险因素和血清学标志物方面得到了很好的表征。还使用颈动脉超声、冠状动脉钙和颈动脉和主动脉壁的MRI对队列进行表型表征。本申请的具体目的是：1）确定心血管疾病的已知风险因素与冠状动脉壁厚度之间的关系，2）确定冠状动脉壁厚度与冠状动脉钙和颈动脉壁厚度之间的关系，以及3）测量冠状动脉壁厚度随时间的进展。MRI直接测量冠状动脉壁厚度与梅萨中现有的疾病标志物相结合，将是评估这些标志物与冠状动脉床早期病理变化关系的有效方法。在早期阶段直接确定冠状动脉粥样硬化程度的能力将导致对冠状动脉危险因素及其对动脉粥样硬化发展的影响的更好理解。

DESCRIPTION (provided by applicant): Direct and noninvasive visualization of the extent of coronary artery atherosclerosis is a major goal in the effort to assess coronary heart disease. Coronary artery calcium and carotid intima medial thickness are examples of surrogate markers of coronary atherosclerosis that attempt to non-invasively define the extent of coronary artery disease present. Coronary calcium in particular is a marker for coronary atherosclerotic burden but is a minor component of total plaque and is not present in early plaque. Coronary artery wall MRI is a new method to directly measure the thickness of the coronary artery wall, and is the only existing noninvasive test without ionizing radiation that can directly interrogate the coronary vasculature and provide a measure of disease burden at this early stage. Prior studies have shown increased coronary artery wall thickness is detected by MRI when no or minimal narrowing of the coronary artery lumen is present. Thus, this study proposes to assess the role of coronary artery wall thickness as a measure of early atherosclerotic disease using MRI, and 2) to determine the relationship of coronary artery wall thickness to both known risk and other noninvasive surrogate markers of atherosclerosis. This study will be performed within the context of the Multi-Ethnic Study of Atherosclerosis (MESA), an NHBLI prospective study of 6814 subjects without clinically manifest atherosclerotic disease. The underlying hypothesis of the MESA study is that the pathway from risk factors to clinical disease is through the development of subclinical disease. The MESA cohort is well characterized in terms of traditional risk factors and serologic markers for atherosclerotic disease. There is also phenotypic characterization of the cohort using carotid ultrasound, coronary calcium and MRI of the carotid and aortic wall. The specific aims of this application are to 1) determine the relationship between known risk factors for cardiovascular disease and coronary artery wall thickness, 2) determine the relationship between coronary artery wall thickness and coronary artery calcium and carotid wall thickness and 3) measure the progression of coronary artery wall thickness over time. The combination of direct coronary artery wall thickness measurement by MRI with the existing disease markers in MESA will be an effective way to assess the relationship of these markers to early pathologic changes in the coronary arterial bed. The ability to directly define the extent of coronary atherosclerosis at an early stage should lead to an improved understanding of coronary risk factors and their impact on atherosclerosis development.