4D SSFP MRI for Detecting Functionally Important Coronary Artery Stenosis at Rest

描述（由申请人提供）：冠状动脉疾病是美国的主要死亡原因。据估计，美国有近700万人患有冠状动脉疾病（CAD），每年约有50万人死于冠心病。冠心病最常见的形式是冠状动脉狭窄，导致心肌供血和供氧减少。这些功能损伤的准确早期检测可能允许介入血运重建程序，以重新建立血流到受影响的区域。血运重建的缺失增加了心源性猝死的风险。目前还没有一种无创的方法可以准确地检测出CAD引起的局部血流差异。该建议的广泛和长期目标是准确指导血运重建策略，并利用磁共振成像（MRI）监测冠状动脉疾病治疗的疗效。我们提出了一种新的方法来检测临床上显着的非血流限制性冠状动脉狭窄（定义为冠状动脉管腔半径减少70%）的存在。所提出的方法依赖于使用心脏相位分辨稳态自由进动（SSFP）磁共振（MR）信号的变化，这些信号源于狭窄动脉供应的心肌区域的局部血容量和氧合变化。与其他MRI方法相比，该方法的主要优点是它可以在静息条件下检测功能显著的冠状动脉狭窄，从而消除了使用药物应激诱导剂评估冠状动脉灌注储备变化的需要。拟议的项目将分三个阶段发展：(1)第一阶段将包括技术发展，目标是开发一种自由呼吸、快速的MR方法，用于获取和评估整个心脏的心脏相位依赖的SSFP信号。(2)项目第二阶段将使用标准MR方法独立评估健康犬模型心肌血容量和氧合的阶段性变化。本研究的主要目的是证明SSFP成像可以同时检测犬模型的血容量和氧合变化，并且灵敏度更高。(3)我们建议的最后阶段将侧重于评估急性冠状动脉狭窄动物模型中心肌血容量和氧合的心相分解变化。本研究的目的是证明SSFP方法在同时识别由狭窄的冠状动脉供应的心肌区域的血容量和氧合变化方面提供了更高的灵敏度。这些研究将为确定人类在静息状态下是否存在功能显著的冠状动脉狭窄提供基础。公共卫生相关性：一种准确、无创的方法检测临床意义重大的冠状动脉疾病，可以为血运重建提供必要的动力，防止心源性猝死。该建议提出了一种基于mri的方法，有可能彻底改变心脏检查的方式，旨在检测临床显著的冠状动脉疾病，在临床环境中进行很少或没有患者不适。最重要的是，所提出的方法具有无创检测冠状动脉疾病的潜力，指导初始治疗，并使患有该疾病的患者群体能够进行临床管理。

DESCRIPTION (provided by applicant): Coronary artery disease is the leading cause of death in the United States. It is estimated that nearly 7 million people are living with coronary artery disease (CAD) in the US and about half a million people die from it each year. The most common form of CAD leads to narrowing of the coronary arteries (stenosis) resulting in reduced blood flow and oxygen supplied to the heart muscle. Accurate early detection of these functional impairments may permit interventional revascularization procedures to re-establish blood flow to the affected regions. The absence of revascularization increases the risk of sudden cardiac death. Currently there are no noninvasive methods that can accurately detect regional flow differences due to CAD. The broad and long term goal of this proposal is to accurately guide revascularization strategies and to monitor the efficacy of the treatment of coronary artery disease with magnetic resonance imaging (MRI). We propose a new method for detecting the presence of a clinically significant non flow-limiting coronary artery stenosis (defined as a decrease in coronary artery lumen radius by 70%). The proposed method relies on the use of cardiac phase-resolved steady-state free precession (SSFP) magnetic resonance (MR) signal changes originating from regional blood volume and oxygenation changes in the myocardial territory supplied by a stenotic artery. The principle advantage of this method over other MRI methods is that it can permit the detection of a functionally significant coronary stenosis under resting conditions, thereby eliminating the need to assess coronary perfusion reserve changes with pharmacological stress-inducing agents. The proposed project will be developed in three stages: (1) The first stage will consist of technical developments with the objective of developing a free-breathing, fast MR method for acquiring and evaluating cardiac phase-dependent SSFP signals over the whole heart. (2) The second stage of the project will use standard MR methods for evaluating phasic changes in myocardial blood volume and oxygenation independently using healthy canine models. The primary goal of this aim is to demonstrate that blood volume and oxygenation changes can be simultaneously detected with SSFP imaging in the same canine models with improved sensitivity. (3) The final stage of our proposal will focus on evaluating cardiac phase-resolved changes in myocardial blood volume and oxygenation in animal models with acute coronary stenosis. The goal of this study will be to demonstrate that the SSFP method provides enhanced sensitivity for simultaneously identifying changes in blood volume and oxygenation in a myocardial territory supplied by a stenotic coronary artery. These studies will provide the basis for identifying the presence of a functionally significant coronary stenosis in humans under resting conditions. PUBLIC HEALTH RELEVANCE: An accurate and noninvasive method for detecting clinically significant coronary artery disease can provide the necessary impetus for revascularization and prevent sudden cardiac deaths. This proposal presents a MRI-based method that has the potential to revolutionize the way cardiac exams aimed at detecting clinically significant coronary artery disease are performed in clinical settings with little or no patient discomfort. Most importantly, the proposed method has the potential to non-invasively detect coronary artery disease, guide initial treatment, and enable clinical management in patient populations with the disease.