MRI Determination of Carotid Atherosclerosis Progression

描述(由申请人提供)：本项目的总体目标是确定颈动脉分叉处有意义的动脉粥样硬化描述参数随时间的变化。早期对颈动脉疾病的研究受到成像限制的阻碍。非侵入性磁共振成像(MRI)方法现在可以用来三维评估颅外颈动脉疾病的几何和成分形态，这是中风的主要来源。这些新方法可以同时评估血管壁内的流腔和疾病。 这项研究将在中到重度颅外颈动脉疾病的患者中，检测最大狭窄管腔横截面积和斑块成分的异质性随时间的变化。将在基线和一年后对300名患者进行成像。为了实现这个项目的目标，已经成立了一个多中心财团。通过组建这个联盟，将有可能招募到足够的统计能力来回答研究的具体目标所需的患者数量。此外，这项研究的多中心组成将提供比单一中心所能确定的更具一般性的结果。除了测量斑块的主要描述符的变化外，还将测量其他描述符(如斑块体积、斑块不规则性或特定斑块成分的体积)随时间的变化。这项应用的次要目标是确定生化标记物是否与斑块变化相关，以及是否可以使用半自动后处理工具来有效地分析动脉粥样硬化性疾病的MRI图像。 该项目的结果将有助于确定一项更大规模的研究所需的受试者数量，该研究旨在确定哪些三维形态的特定描述符最能预测斑块进展，并将证实该联盟能够实现招募和保留目标。这项规模更大的研究将提供对斑块不稳定机制的洞察，并将有助于实现确定哪些成像特征在定义颈动脉疾病的神经风险方面最敏感的长期目标。这些成像方法的建立对旨在确定动脉粥样硬化对药物干预的反应的药物试验也将是有价值的。

DESCRIPTION (provided by applicant): The overall goal of this project is to determine the change over time of parameters that are meaningful descriptors of atherosclerosis at the carotid bifurcation. Earlier studies of carotid disease have been hampered by imaging limitations. Non-invasive Magnetic Resonance Imaging (MRI) methods are now available that permit a three-dimensional evaluation of the geometric and compositional morphology of disease of the extracranial carotid arteries, a major source of stroke. These new methods permit an evaluation of both the flow lumen and the disease within the vessel wall. This study will examine, in patients with moderate to severe disease of the extracranial carotids, the changes over time in the cross-sectional area of the maximally stenosed lumen and in the heterogeneity of plaque composition. Imaging will be performed at baseline and one year later in 300 patients. A multi-center consortium has been formed to meet the goals of this project. By assembling this consortium, it will be possible to recruit the number of patients needed to answer the specific aims of the study with sufficient statistical power. Further, the multi-center composition of this study will provide results of greater generality than can be established by a single center. In addition to measuring changes in the primary descriptors of plaque, change over time of other descriptors (such as plaque bulk, plaque irregularity, or the volumes of specific plaque components) will be measured. Secondary aims of this application are to determine whether biochemical markers are correlated with plaque change, and whether semi-automated postprocessing tools can be used to efficiently analyze the MRI images of atherosclerotic disease. The results of this project will help define the number of subjects needed in a larger study aimed at determining which specific descriptors of 3-D morphology are most predictive of plaque progression, and would confirm that this consortium can attain that recruitment and retention goal. The larger study would provide an insight into mechanisms of plaque instability and would be helpful in achieving the long-term goal of identifying which imaging features are most sensitive in defining the neurological risk of carotid disease. Establishment of these imaging methods will also be valuable for drug trials aimed at determining the response of atherosclerosis to pharmacological interventions.