NONINVASIVE NMR IMAGING OF HUMAN MYOCARDIAL ARCHITECTURE

描述(改编自申请者摘要)：拟议的研究 试图绘制出主要的心肌结构元素，肌纤维和 卵裂面，使用新的非侵入性磁共振成像(MRI) 方法：研究方法。心脏力学主要是心肌的反映 架构，然而这种架构很难在 实验室和活体评估是不可能的。调查人员已经 开发了一种新的磁共振成像方法来绘制 基于心肌各向异性扩散测量的心肌 水。在初步研究中，他们已经表明， 这些主要的材料各向异性(纤维和解理面)可以是 利用实时刺激回声磁共振实现体内外可视化 技术与组织学有很好的相关性。磁共振成像方法学拥有 与以前的分析方法相比有两个压倒性的优势 心肌结构的特征。首先，它可能是天气预报性的，揭示了 心肌纤维和裂解面的构筑 心在同一时间。第二，它是非侵入性的：完全适用于 活生生的人类主体，不会对它所寻求的建筑造成扭曲 去观察。 这项拟议的研究将验证心肌磁共振扩散图 建筑，使用组织学建立局部之间的对应关系 扩散张量的特定特征向量和特定细胞构型 功能。一个广泛的研究扩散测量的现象在一个 运动系统，在体外和离体犬心脏制剂中，将 然后被执行。这种方法解决的关键技术挑战是 检测水分子在水中的微观运动 心脏剧烈宏观运动的背景。这个 调查人员随后将调查获取此类数据的可行性。 在人的主体上，首先是优化收购战略，其次是 用核磁共振技术研究体外培养的人心肌构筑 探讨磁共振成像显示人体心肌构筑的能力 活着。这些测量将提供一个机会来解决以下几个问题 关于心肌结构和功能的经典问题，还提供了 为后续心脏病理生理学研究奠定基础。

DESCRIPTION (Adapted from Applicant's Abstract): The proposed research seeks to map the principal myocardial structural elements, myofibers and cleavage planes, using novel,noninvasive magnetic resonance imaging (MRI) methods. Cardiac mechanics is primarily the reflection of myocardial architecture, yet this architecture has been difficult to assess in the laboratory and impossible to assess in vivo. The investigators have developed a novel MRI methodology to map the architectonics of the myocardium based upon measurement of the anisotropic diffusion of myocardial water. In preliminary studies, they have shown that the orientations of these principal material anisotropies (fibers and cleavage planes) can be visualized ex vivo and in vivo using a real time stimulated echo MR technique with excellent correlation by histology. MRI methodology possess two overwhelming advantages compared with previous methods for the analysis of myocardial architecture. First, it is potentially synoptic, revealing the architecture of myocardial fibers and cleavage planes throughout the heart at the same time. Second, it is noninvasive: fully applicable to the living human subject and causing no distortion of the architecture it seeks to observe. The proposed research will validate the MR diffusion maps of myocardial architecture, using histology to establish the local correspondence between specific eigenvectors of the diffusion tensor and specific cytoarchitectonic features. A broad study of the phenomenon of diffusion measurement in a moving system, in vitro and in an isolated canine heart preparation, will then be performed. The key technical challenge addressed by this method is the detection of the microscopic motions of water molecules against the background of the vigorous macroscopic motion of the heart. The investigators will then investigate the feasibility of obtaining such data in the human subject, first optimizing acquisition strategy, next characterizing human myocardial architecture ex vivo with MRI, and last investigating the capacity of MRI to define human myocardial architecture in vivo. These measurements will afford an opportunity to address several classic questions about myocardial structure and function, and also provide a foundation for subsequent studies of cardiac pathophysiology.