IMAGING MYOCARDIAL PERFUSION WITH NMR

使用 NMR 成像心肌灌注

• 批准号: 6043938
• 负责人: ROBERT M WEISSKOFF
• 金额: $ 22.88万
• 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 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6043938
• 关键词: artery stenosis; bioimaging /biomedical imaging; biomechanics; blood flow measurement; blood volume; clinical research; computer simulation; diagnosis design /evaluation; dipyridamole; disease /disorder model; dogs; heart circulation; heart function; heart imaging /visualization /scanning; hemodynamics; human subject; image enhancement; magnetic resonance imaging; model design /development; myocardium; nuclear magnetic resonance spectroscopy; outcomes research; oxygen consumption; swine; vasodilation

DESCRIPTION (Adapted from Applicant's Abstract): The goal of this research is to develop and validate novel MR imaging approaches to quantify changes in local myocardial perfusion without the use of exogenous MR contrast media. We propose theoretical models and experimental protocols to detect, characterize and exploit changes in the intrinsic NMR signals caused by changes in the underlying physiology of the myocardium. These signals, which arise from the interaction of physical, chemical, biological and physiological variables, are subtly altered when the heart is perturbed. For example, the observed longitudinal relaxation time (T1) can be sensitized to changes in myocardial perfusion, and thus appropriately T1-weighted images can be made into quantitative perfusion maps. In addition, due to the underlying magnetic properties of oxy- and deoxyhemoglobin, the transverse relaxation times (T2*, T2) are inherently sensitive to changes in blood oxygenation. Preliminary results suggest that intrinsic NMR imaging approaches can measure myocardial flow reserve in animals and in man. In the proposed research, the investigators seek first to demonstrate that the amplitude of these changes can be predicted in a blood-perfused, ex vivo, canine heart model at 4.7 T, in which the important underlying physiological parameters (blood flow and volume, blood oxygenation, and hematocrit) can be controlled or measured. Following optimization of image quality at 1.5 T, they seek to exploit these changes to produce quantitative maps of the results of vasodilatory (adenosine) stress, in an intact porcine model that includes flow limitation via coronary artery stenosis. They hypothesize that they can measure local myocardial flow reserve using either T1 or T2/T2* effects under vasodilatory challenge: T1 changes can be directly interpreted as flow changes, whereas the T2 changes are the result of an increase in blood oxygenation due to the increased flow with minimal increased oxygen consumption. The applicants will optimize the imaging methodologies, determine which method more robustly detects deficits in perfusion reserve in animal models of coronary artery disease and demonstrate its feasibility in normal human subjects for subsequent studies in patients with suspected coronary artery disease.

描述（改编自申请人摘要）：本研究的目标 是开发和验证新的磁共振成像方法， 在不使用外源性MR造影剂的局部心肌灌注中 媒体 我们提出了理论模型和实验协议来检测， 表征和利用由以下因素引起的固有NMR信号的变化 心肌的潜在生理变化。 这些信号， 它们是由物理、化学、生物和 当心脏受到干扰时，生理变量会发生微妙的变化。 例如，观察到的纵向弛豫时间（T1）可以是 对心肌灌注的变化敏感， T1加权图像可制成定量灌注图。 在 此外，由于氧和 在脱氧血红蛋白中，横向弛豫时间（T2*，T2）固有地是 对血氧变化敏感。 初步结果表明 固有的核磁共振成像方法可以测量心肌血流储备， 动物和人。 在拟议的研究中，研究人员首先试图证明， 这些变化的幅度可以在血液灌注中预测， 体内，犬心脏模型在4.7 T，其中重要的基础 生理参数（血流量和血容量、血氧和 血细胞比容）可以被控制或测量。 图像跟踪优化 质量在1.5 T，他们试图利用这些变化来产生定量 完整猪血管舒张（腺苷）应激结果图 包括通过冠状动脉狭窄的血流限制的模型。 他们 假设他们可以使用以下两种方法测量局部心肌血流储备 血管舒张激发下的T1或T2/T2* 效应：T1变化可能是 直接解释为流量变化，而T2变化是 血液氧合增加，由于流量增加， 增加氧气消耗。 申请人将优化成像 方法，确定哪种方法更可靠地检测缺陷， 冠状动脉疾病动物模型的灌注储备， 证明其在正常人类受试者中的可行性，用于后续研究 疑似冠状动脉疾病的患者。