NMR STUDIES OF MYOCARDIAL PERFUSION

这个项目的总体目标是开发和验证小说 局部心肌灌注和血流定量方法的探讨 用本征核磁共振对比度确定储量及实用价值 这些技术在检测冠状动脉疾病(CAD)中的作用。 天然橡胶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 最小或完全非侵入性心脏测量 灌注和局部心肌工作。支持的实验 这位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) 放松的时候在心里。灌注改变直接发生在T1之后。 偶联引起的静脉血氧合的变化 在流量和功能之间，更改T2。尽管一些较早的 对大脑的工作(项目1)可以延伸到心脏， 心脏研究具有独一无二的挑战性，因为 在不断移动的物体中测量微小变化的问题 管风琴。本征核磁共振变化与核磁共振的关系 潜在的生理学被各种其他因素复杂化。 微观和宏观过程。这项研究将 调查这些影响中的几个，包括内部/外部角色- 血管水交换，利用磁化传递效应 在T1流量度中，不断变化的磁环境 心跳；以及由于以下原因导致的回声时间较长时的伪像变化 心肌图像对比度的血流消退。我们试图利用 这些变化产生了量化地图的结果 使用血管扩张剂(腺苷和 多巴酚丁胺)在完整的猪冠状动脉模型上的挑战 狭窄和心肌顿抑。我们假设学位 的局部T1和T2*加权图像增强 血管扩张与血管局部的变化直接相关。 微球-测量的流量。然后，研究将在 疑似冠心病患者使用腺苷挑战 测定本征核磁共振对比度的灵敏度 生理意义上的CAD与N13氨PET的比较 测量。

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.