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小说 量化局部心肌灌注和流动 使用固有的NMR对比度储备并确定实用程序 这些技术在检测冠状动脉疾病（CAD）中。 NR技术和最新发现的最新进展 关于对MR图像对比的贡献可能允许 最小或完全无创的心脏测量 灌注和局部心肌工作。支持的实验 该PPG和其他PPG表明流量的变化和 血氧影响纵向（T1）和横向（T2） 心脏放松的时间。 灌注变化直接改变T1。 从耦合中得出的静脉血氧合的变化 在流和功能之间，改变T2。 虽然较早 大脑的工作（项目1）可以扩展到心脏， 心脏研究非常具有挑战性，因为一般 衡量不断移动的小变化的问题 器官。 内在的NMR之间的关系变化和 潜在的生理学使许多其他的生理学变得复杂 显微镜和宏观过程。这项研究会 研究其中几种效果，包括在/外部的角色 血管水交换，磁化转移效应的使用 T1的流量测量，随着磁性环境的变化 心跳；和人工变化在较长的回声时间上 在心肌图像对比度上进行流动。我们试图利用 这些变化以产生结果的定量图 使用血管舒张的药理胁迫（腺苷和 冠状动脉完整猪模型中的多巴胺胺） 狭窄和心肌惊人。 我们假设该学位 本地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。 然后将进行研究 怀疑CAD使用腺苷挑战的患者 确定固有NMR对比的灵敏度检测 与N13氨PET相比，生理意义的CAD 测量。