QUANTITATION OF DIFFUSION EFFECTS IN MR IMAGING OF BRAIN

大脑 MR 成像中扩散效应的量化

• 批准号: 6393629
• 负责人: JIANHUI ZHONG
• 金额: $ 24.44万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-05-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6393629
• 关键词: Aplysia; alternatives to animals in research; bioimaging /biomedical imaging; brain circulation; brain disorder diagnosis; cell water; clinical research; computer simulation; diagnosis design /evaluation; diagnosis quality /standard; diffusion; disease /disorder model; generalized seizures; human subject; immunocytochemistry; kindling; laboratory rat; magnetic resonance imaging; mathematical model; method development; nuclear magnetic resonance spectroscopy; phantom model; stroke

This is a competing renewal of a grant that has been funded by the NIH. In the next phase of the project, we plan to continue to achieve the general aims at quantitation of diffusion effects in MR imaging of brain. In the past four years since the beginning of the current funding period, great progress has been made in the understanding of molecular diffusion in tissues, and in the development of new clinical applications of diffusion-weighted MR imaging. New questions, however, have emerged and new techniques have opened up new opportunities for better quantitation and further development. In the next phase we plan to develop new spectroscopy and imaging methods, and concentrate on the following areas: (1) Contributions of blood microcirculation and cytoplasmic streaming to apparent diffusion coefficient (ADC). We will develop methods based on the Velocity Exchange Spectroscopy (VEXSY) (Callaghan et al 1995) to detect water movement of different degrees of correlation and coherence. (2) Changes in ADC with alterations of properties of cellular compartments associated with brain injury. We will use signals from multiple-quantum transition and VEXSY method to detect water diffusion in different environments under controlled cellular morphological changes, and we will measure compartmental tortuosity. (3) Effects of magnetic susceptibility on ADC. New methods will be developed to selectively detect and quantify internal field gradients induced by magnetic susceptibility distributions. (4) Relationship between the ADC and neuronal electrical activities. We will use electrical stimulation of varying duration and intensity to study a rat kindling model of seizures with well characterized anatomic and functional network. We will correlate ADC changes with electrophysiological and immunocytochemistry measurements. (5) diffusion anisotropy changes associated with pathologic conditions or cerebral activity. We will use rat kindling and forepaw stimulation models in electrical stimulation studies, and human volunteers in activation studies. In all these areas, we will continue to use computer simulations to help in the experiment design, validation and quantitation of the results. The project will focus on studies with phantoms, animals, and human volunteers to look at biophysical basis of diffusion and its alteration during brain injury, but the outcomes from these studies should have a direct impact on brain diffusing imaging in a wide range of clinical settings.

这是一项由NIH资助的补助金的竞争性更新。在项目的下一阶段，我们计划继续实现大脑MR成像中扩散效应定量的总体目标。自本资助期开始以来，在过去的四年中，在对组织中分子扩散的理解以及扩散加权磁共振成像的新临床应用的开发方面取得了很大进展。然而，新的问题已经出现，新的技术为更好的定量和进一步发展开辟了新的机会。在下一阶段，我们计划开发新的光谱和成像方法，并将重点放在以下方面：(1)血液微循环和细胞质流动对表观扩散系数（ADC）的贡献。我们将开发基于速度交换光谱（VEXSY） （Callaghan et al . 1995）的方法来检测不同程度的相关性和相干性的水运动。(2) ADC的改变与脑损伤相关的细胞室性质的改变。我们将使用多量子跃迁信号和VEXSY方法来检测受控细胞形态变化下不同环境下的水扩散，并测量室扭曲度。磁化率对ADC的影响。将开发新的方法来选择性地检测和量化由磁化率分布引起的内部场梯度。(4) ADC与神经元电活动的关系。我们将使用不同持续时间和强度的电刺激来研究具有良好解剖和功能网络特征的癫痫发作大鼠点火模型。我们将把ADC的变化与电生理和免疫细胞化学测量相关联。(5)扩散各向异性变化与病理状况或大脑活动有关。我们将在电刺激研究中使用大鼠点火和前爪刺激模型，在激活研究中使用人类志愿者。在所有这些领域，我们将继续使用计算机模拟来帮助实验设计，验证和结果的量化。该项目将重点研究幻影、动物和人类志愿者，以研究脑损伤期间弥散的生物物理基础及其改变，但这些研究的结果将对广泛的临床环境中的脑弥散成像产生直接影响。