NONGAUSSIAN DIFFUSION BEHAVIOR IN BRAIN

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。本研究的目标是开发模型的非随机扩散在人体内使用扩散张量成像（DTI）的研究人员和合作者的P41 RR 09784？斯坦福大学的先进磁共振技术中心？努力使用高水平扩散敏化（B 2000 sec/mm 2）的研究似乎表明ADC具有单独的组分，在较高的B值下产生非单指数信号衰减和扩散敏化。质子扩散的研究在高B值，但是，可能会提供组织的对比度从a？慢点ADC组分（双指数模型），可能与细胞内室的扩张（也被视为细胞毒性水肿）更相关，因为它可能与？快吗？ADC水人口。在对此进行建模后，我们发现这主要发生在纤维可能交叉的白色物质中，产生非随机扩散。在低B值时，较快ADC分量占主导地位，而在较高b值时，第二较慢ADC分量变得明显。值得注意的是，差异很大，并且缺乏任何可观察到的缓慢FA组织对比度。我们已经完成了这项工作的所有预期工作，并提交了这些结果作为支持我们的模型的公开摘要。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goal of this research is to develop models of non-random diffusion in the human body using diffusion tensor imaging (DTI) for the investigators and collaborators on the P41 RR09784 ?Center for Advanced MR Technology at Stanford? effort. Studies using high levels of diffusion sensitization (b 2000 sec/mm2) appear to indicate that the ADC has separate components, producing a non-monoexponential signal decay with diffusion sensitization at the higher b values. Studies of proton diffusion at high b values, however, may provide tissue contrast from a ?slower? ADC component (of the biexponential model) that may more relevant to the expanding intracellular compartment (also seen as cytotoxic edema), since it may be in exchange with the ?fast? ADC water population. Upon modeling this, we find that this occurs mostly in white matter where fibers may be crossing, producing non-random diffusion. A faster ADC component dominates at low b values, while at higher b-values, a second, slower ADC component becomes apparent. It is striking to note the large differences and the lack of any observable slow FA tissue contrast. We have finished all anticipated work on this effort and have submitted these results as a published abstract supporting our models.