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。冠状动脉钙和颈动脉内膜内侧厚度是冠状动脉粥样硬化的替代标志物，它们试图无创地确定冠状动脉疾病的范围。特别是冠状动脉钙是冠状动脉粥样硬化负荷的一个标志，但它是总斑块的一个次要组成部分，在早期斑块中不存在。冠状动脉壁MRI是一种直接测量冠状动脉壁厚度的新方法，是目前唯一一种无需电离辐射即可直接询问冠状动脉血管并在早期阶段提供疾病负担测量的无创检测方法。先前的研究表明，当冠状动脉管腔没有狭窄或只有很小的狭窄时，MRI可以检测到冠状动脉壁厚度增加。因此，本研究建议利用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指标的作用，以及2)确定冠状动脉壁厚度与已知风险和其他非侵入性动脉粥样硬化替代标志物的关系。本研究将在多民族动脉粥样硬化研究（MESA）的背景下进行，这是一项NHBLI前瞻性研究，共有6814名无临床表现的动脉粥样硬化疾病的受试者。MESA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。MESA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具有很好的特征。通过颈动脉超声、冠状动脉钙化和颈动脉和主动脉壁MRI对该队列进行表型表征。该应用程序的具体目的是：1)确定已知心血管疾病危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；3)测量冠状动脉壁厚度随时间的变化。MRI直接测量冠状动脉壁厚与MESA中已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变关系的有效方法。在早期阶段直接确定冠状动脉粥样硬化程度的能力将有助于提高对冠状动脉危险因素及其对动脉粥样硬化发展的影响的理解。

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.