INTEGRATED MRI EXAM OF FLOW RESERVE

血流储备综合 MRI 检查

• 批准号: 2029656
• 负责人: HOWARD L KANTOR
• 金额: $ 31.32万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2001-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2029656
• 关键词: adenosine; artery stenosis; blood flow measurement; clinical research; computer simulation; coronary artery; diagnosis design /evaluation; dobutamine; dogs; heart circulation; heart imaging /visualization /scanning; hemodynamics; human subject; magnetic resonance imaging; myocardial ischemia /hypoxia; noninvasive diagnosis; oxygen consumption; positron emission tomography; swine; ultrasound blood flow measurement

The goal of this research is to validate and optimize an integrated magnetic resonance (MR) approach that can noninvasively determine coronary flow reserve and myocardial oxygenation in ischemic heart disease. Our real time MR approach uses the simultaneous acquisition of time-of-flight (TOF) coronary artery velocity measurements and blood-oxygenation level dependent (BOLD) assessment of myocardial oxygenation. Our modified TOF MR tomographic approach measures coronary flow velocity using the intrinsic contrast generated by flowing blood. Our preliminary data demonstrate normal coronary reserve index during vasodilator challenge in normal volunteers, and abnormal flow responses in patients with obstructive coronary lesions. Following optimization in animals, data will be acquired in normal volunteers and in patients with focal coronary artery disease (CAD), with Doppler flow reserve correlation in the latter. Characterization of the physiological significance of coronary lesions will be enhanced by the simultaneous acquisition of images sensitive to changes in myocardial oxygen consumption. We will exploit the intrinsic sensitivity of MR to changes in deoxyhemoglobin content, thereby producing T2*contrast. This susceptibility contrast in the heart depends on may parameters including coronary flow, hemoglobin content, coronary venous volume, and local myocardial metabolism (oxygen consumption). We will develop both the theory and experimental techniques required to translate the changes we observe in MR images into changes in local physiological variables. We will combine computer simulations, that have already proven successful in explaining MR changes with brain activation, with novel experiments on isolated blood-perfused heats, using EPI in order to quantify these changes in vivo. Once optimized, data on regional myocardial perfusion will be acquired in normal volunteers and in patients with focal coronary disease, using positron emission tomography (PET) for comparison on the latter. Our overall objectives are both to improve imaging of the macroscopic and microscopic blood supply of the heart and to gain a better understanding of the role of coronary flow limitation in the pathogenesis and clinical evolution of ischemic heart disease. The long term goal of this research is to develop a protocol that integrates these approaches into a single cardiac MR exam.

这项研究的目的是验证和优化集成的 磁共振（MR）方法可以无创 确定冠状动脉流量和心肌充氧 缺血性心脏病。 我们的实时方法先生使用 同时获得飞行时间（TOF）冠状动脉 速度测量和血氧水平取决于 （粗体）心肌氧合的评估。 我们修改的TOF MR断层扫描方法测量使用冠状动脉流速度 流动血液产生的固有对比。 我们的初步 数据显示血管扩张器期间正常冠状动脉储备指数 正常志愿者的挑战和异常流动反应 阻塞性冠状动脉病变的患者。 遵循优化 在动物中，将在正常志愿者和 局灶性冠状动脉疾病（CAD）患者多普勒 后者的流量储备相关性。 冠状动脉的生理意义的表征 通过同时获得图像，将增强病变 对心肌消耗的变化敏感。 我们将 利用MR对变化的内在灵敏度 脱氧血红蛋白含量，从而产生T2*对比度。 这 心脏中的敏感性对比取决于5月参数 包括冠状动脉流，血红蛋白含量，冠状静脉 体积和局部心肌代谢（消耗氧）。 我们将发展理论和实验技术 需要将我们在MR图像中观察到的更改转换为 局部生理变量的变化。 我们将结合 计算机模拟已经证明了成功 通过新颖的方式解释MR的变化 使用EPI进行孤立的血液散发热量实验 在体内量化这些变化。 一旦优化，区域数据 心肌灌注将在普通志愿者和 使用正电子发射的局灶性冠状动脉疾病的患者 断层扫描（PET），用于对后者进行比较。 我们的整体目标都是改善成像的成像 心脏的宏观和微观血液供应并获得 更好地理解冠状动脉流限制在 缺血性心脏病的发病机理和临床进化。 这 这项研究的长期目标是制定一个协议 将这些方法整合到单个心脏MR检查中。