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，在美国有近700万人患有冠状动脉疾病（CAD），每年约有50万人死于CAD。最常见的CAD形式导致冠状动脉变窄（狭窄），导致供应给心肌的血流和氧气减少。这些功能障碍的准确早期检测可能允许介入血运重建手术重建血流到受影响的区域。缺乏血运重建会增加心源性猝死的风险。目前还没有非侵入性的方法，可以准确地检测区域流量的差异，由于CAD。该提案的广泛和长期目标是准确指导血运重建策略，并监测磁共振成像（MRI）治疗冠状动脉疾病的疗效。我们提出了一种新的方法，用于检测临床上显著的非限流性冠状动脉狭窄（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，源于局部血容量和氧合变化的心肌领土提供的狭窄动脉。该方法相对于其他MRI方法的主要优点是，它可以允许在静息条件下检测功能显著的冠状动脉狭窄，从而消除了使用药理学应激诱导剂评估冠状动脉灌注储备变化的需要。拟议项目将分三个阶段开发：（1）第一阶段将包括技术开发，目标是开发一种自由呼吸、快速MR方法，用于采集和评估整个心脏上的心脏相位相关SSFP信号。(2)该项目的第二阶段将使用标准MR方法，使用健康犬模型独立评估心肌血容量和氧合的阶段性变化。该目的的主要目标是证明在相同的犬模型中，可以使用SSFP成像同时检测血容量和氧合变化，并且灵敏度提高。(3)我们建议的最后阶段将集中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脏相位分辨变化。本研究的目的是证明SSFP方法提供了增强的灵敏度，可同时识别狭窄冠状动脉供血心肌区域中的血容量和氧合变化。这些研究将为确定静息状态下人体存在功能显著的冠状动脉狭窄提供基础。公共卫生相关性：一个准确和无创的方法来检测临床上显著的冠状动脉疾病可以提供必要的推动血运重建和预防心脏猝死。该提案提出了一种基于MRI的方法，该方法有可能彻底改变旨在检测临床显著冠状动脉疾病的心脏检查在临床环境中进行的方式，而很少或没有患者不适。最重要的是，所提出的方法有可能非侵入性地检测冠状动脉疾病，指导初始治疗，并使临床管理的患者群体的疾病。

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.