NONGAUSSIAN DIFFUSION BEHAVIOR IN BRAIN

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。本研究的目的是利用扩散张量成像（DTI）为P41 RR09784 ？斯坦福大学高级磁共振技术中心？努力。使用高水平扩散敏化（b 2000秒/mm2）的研究似乎表明ADC具有单独的组件，在较高的b值下产生非单指数信号衰减与扩散敏化。然而，在高b值下对质子扩散的研究，可以提供较慢的组织对比。ADC成分（双指数模型）可能与扩大的细胞内隔室（也被视为细胞毒性水肿）更相关，因为它可能与快速？ADC水域人口。通过建模，我们发现这种情况主要发生在纤维可能交叉的白质中，产生非随机扩散。较快的ADC组件在低b值时占主导地位，而在高b值时，第二个较慢的ADC组件变得明显。值得注意的是巨大的差异和缺乏任何可观察到的缓慢FA组织对比。我们已经完成了这项工作的所有预期工作，并将这些结果作为支持我们模型的发表摘要提交。

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.