Software for the Analysis and Visualization of High Angular Resolution DTI Data

描述(申请人提供)：弥散张量成像(DTI)测量的大脑弥散各向异性(DA)与白质(WM)结构有关，因此是与退行性WM疾病相关的变化的指标。DA的估计也是纤维束映射(FTM)的必要前驱，FTM具有了解大脑连接的潜力。在DTI中，作为编码方向的函数的信号变化与用于估计DA的局部组织扩散(LTD)有关。在标准DTI中，DA基于简化的LTD模型，只需要几个编码方向。但最近的工作表明，LTD的复杂性可能不能很好地用标准模型来拟合，需要高角分辨率扩散(HARD)和多重扩散加权(Q-空间)来更好地描述LTD。这带来了三个主要问题：1)硬数据和Q空间数据以及DA和FTM结果的分析和显示很复杂；2)用简单的“流线”方法不再可能用硬数据进行FTM；以及3)DA和FTM方法中的误差难以量化。我们最近开发了一个DTI分析插件，用于AFNI(功能神经图像分析)程序。目前提议的主要目标是进一步开发该软件来解决这些问题，以提供一个所有神经科学家都可以访问的DTI分析和可视化平台。我们的第一个具体目标是完全集成、记录和“生产”我们的插件，以便在Afni发行版中传播。此外，我们还将DTI推广到球谐分解(SHD)，以包含更复杂的LTD模型。第二个具体目标是开发快速、准确的SHD计算和显示，以及我们对Q空间的扩展-球面波分解(SWD)，以产生更准确的DA图。我们的第三个具体目标是开发基于偏微分方程(PDE)扩散方程解的FTM例程，增加先验信息，具有用户定义的“种子”位置，并使用先进的可视化方法在高分辨率解剖数据中显示。第四个具体目标是量化和显示DA和FTM中的错误。受我们正在进行的显示酒精滥用患者WM DA变化的工作以及我们最近在胎儿酒精综合征、阿尔茨海默氏症和语言障碍方面的工作的推动，我们的最终长期目标是产生一种定量的DTI分析和可视化工具，以帮助神经科学家对退行性白质疾病进行评估。

DESCRIPTION (provided by applicant): The diffusion anisotropy (DA) in the brain measured by diffusion tensor imaging (DTI) is related to white matter (WM) structure and is thus an indicator for changes associated with degenerative WM diseases. Estimation of DA is also a necessary precursor to fiber tract mapping (FTM), which holds the potential for understanding brain connectivity. In DTI, signal variations as a function of encoding direction are related to the local tissue diffusion (LTD) from which DA is estimated. In standard DTI, DA is based upon a simplified LTD model requiring only a few encoding directions. But recent work has shown that LTD complexity may not be well fit by the standard model and high angular resolution diffusion (HARD) and multiple diffusion weightings (q-space) are needed to better characterize LTD. This poses three major problems: 1) Analysis and display of HARD and q-space data, and DA and FTM results, is complicated; 2) FTM with HARD data is no longer possible by simple "streamline" methods, and 3) Quantitation of errors in DA and FTM methods is difficult. We have recently developed a DTI analysis plugin to the program AFNI (Analysis of Functional Neurolmages). The primary goal of the current proposal is to further develop this software to address these problems to provide a DTI analysis and visualization platform accessible to all neuroscientists. Our first specific aim is to fully integrate, document, and "productize" our plugin, for dissemination in the AFNI distribution. Also, we have generalized DTI to the spherical harmonic decomposition (SHD), to incorporate more complex LTD models. The second specific aim is to develop rapid, accurate computation and display of the SHD, and our extension to q-space, the spherical wave decomposition (SWD), to produce more accurate DA maps. Our third specific aim is to develop FTM routines based on partial differential equation (PDE) diffusion equation solutions, augmented with prior information, with user-defined "seed" locations, and display within high-resolution anatomical data using advanced visualization methods. The fourth specific aim is to quantitate and display errors in DA and FTM. Motivated by our ongoing work showing changes in WM DA in alcohol abuse patients, and our recent work in fetal alcohol syndrome, Alzheimer's, and language disorders, our ultimate long term goal is to produce a quantitative DTI analysis and visualization tool to aid neuroscientists in their ongoing assessment of degenerate white matter diseases.