NMR STUDIES OF MYOCARDIAL PERFUSION

心肌灌注的核磁共振研究

• 批准号: 6102507
• 负责人: THOMAS J BRADY
• 金额: $ 15.88万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-05-28 至 2000-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6102507
• 关键词: blood flow measurement; cardiography; cardiovascular disorder diagnosis; clinical research; contrast media; coronary disorder; diagnosis design /evaluation; heart circulation; heart disorder diagnosis; heart rhythm; hemodynamics; human subject; image enhancement; magnetic resonance imaging; microcapsule; myocardial ischemia /hypoxia; myosins; noninvasive diagnosis; nuclear magnetic resonance spectroscopy; oxygen tension; pharmacokinetics; positron emission tomography; reperfusion; swine; vasomotion

The overall goal of this project is to develop and validate novel approached to quantify local myocardial perfusion and flow reserve using intrinsic NMR contrast and to determine the utility of these techniques in detecting coronary artery disease (CAD). Recent advances in NR technology and recent discoveries regarding contributions to MR image contrast may allow minimally or completely non-invasive measurement of heart perfusion and local myocardial work. Experiments supported by this PPG and others have demonstrated that changes in flow and blood oxygenation affect the longitudinal (T1) and transverse (T2) relaxation times in the heart. Perfusion changes directly alter T1. Changes in venous blood oxygenation, derived from the coupling between flow and function, alter T2. Though some of the earlier work on the brain (Projects 1) can be extended to the heart, cardiac studies are uniquely challenging because of the general problem of measuring small changes in a constantly moving organ. The relationship between the intrinsic NMR changes and the underlying physiology is complicated by a variety of other microscopic and macroscopic processes. This research will investigate several of these effects including the role intra/extra- vascular water exchange, the use of magnetization transfer effects of T1 measures of flow, the changing magnetic environment as the heart beats; and artifactual changes at longer echo times due to flow dephasing on myocardial image contrast. We seek to exploit these changes to produce quantitative maps of the results of pharmacological stress using vasodilatory (adenosine and dobutamine) challenge in intact porcine models of coronary artery stenosis and myocardial stunning. We hypothesize that the degree of local T1 and T2*-weighted image enhancement during vasodilation correlates directly with the local change in microsphere-measured flow. Studies will then be performed in patients with suspected CAD using adenosine challenge to determine the sensitivity of intrinsic NMR contrast for detecting physiologically significant CAD compared to N13 ammonia PET measurements.

该项目的总体目标是开发和验证新颖的 量化局部心肌灌注和流量的方法 使用内在核磁共振对比进行储备并确定效用 这些技术在检测冠状动脉疾病（CAD）中的应用。 NR 技术的最新进展和最新发现 关于对 MR 图像对比度的贡献可能允许 微创或完全无创的心脏测量 灌注和局部心肌做功。实验支持 这个 PPG 和其他人已经证明了流量和 血氧饱和度影响纵向（T1）和横向（T2） 内心的放松时刻。 灌注变化直接改变 T1。 耦合产生的静脉血氧合变化 在流程和功能之间，改变 T2。 虽然有些较早的 对大脑的工作（项目 1）可以扩展到心脏， 心脏研究具有独特的挑战性，因为一般 测量不断移动的微小变化的问题 器官。 固有 NMR 变化与 潜在的生理学因各种其他因素而变得复杂 微观和宏观过程。这项研究将 研究其中的一些影响，包括内部/外部的作用 血管水交换，利用磁化传递效应 T1 测量流量、变化的磁环境作为 心跳；以及较长回波时间下的人为变化 流动相移对心肌图像对比度的影响。我们寻求利用 这些变化产生了结果的定量图 使用血管舒张剂（腺苷和 多巴酚丁胺）对完整猪冠状动脉模型的挑战 狭窄和心肌顿抑。 我们假设度 局部 T1 和 T2* 加权图像增强 血管舒张与局部变化直接相关 微球测量流量。 然后研究将在 疑似 CAD 患者使用腺苷激发 确定用于检测的内在 NMR 对比的灵敏度 与 N13 氨 PET 相比，具有生理意义的 CAD 测量。