Probabilistic White and Gray Matter Atlas of the Adult Human Brain

描述(由申请人提供)：扩散磁共振成像提供了关于活体中人脑的微结构完整性和连通性的丰富信息。高角分辨率扩散成像(HARDI)可以比传统的扩散张量成像(DTI)更准确地描述复杂的神经元微结构，而且它一度较低的扫描效率最近已经可以与DTI相媲美。因此，HARDI正在迅速成为一种强大的研究和临床工具。Hardi信息的空间归一化在a)全脑体素研究，b)感兴趣区(ROI)研究比较潜在的白质纤维方向，以及c)特定于区域的Hardi研究与基于自动图谱的区域分割中是必要的。这种研究的准确性取决于空间归一化的准确性。精确的空间归一化需要一个高质量的代表人脑的Hardi模板。可以构建特定于研究的模板，但有几个限制。此外，在特定于脑束的Hardi调查的情况下，准确的脑束分割还需要伴随着一组语义标签，这些语义标签准确地描绘不同的脑白质脑束(形成准确的脑白质图谱)。目前可用的白质数字地图集是有问题的，因为它们要么是基于解剖地标生成的，因此混合了具有显著不同作用的区域，要么是使用了DTI成像，后者在区域中失败 使用交叉纤维。因此，需要一份详细的概率脑图谱，包括a)代表人脑的高质量Hardi模板，以及b)用Hardi脑束造影术生成的准确的白质标记。由于空间错位在白质微结构的体素研究中可能是有害的，许多研究采用了一种对齐不变的方法，即信息首先被投影到白质“骨架”上，然后对骨架进行体素分析。使用基于图谱的分割的特定领域的研究也可能受到图谱到受试者配准错误的负面影响，如果有准确的白质图谱的骨架版本，则可以从对齐不变方法中受益。最后，在神经成像研究中，关于白质和灰质两者的信息经常被组合在一起，尽管可以在空间上匹配独立生成的白质和灰质图谱，但由于配准误差以及由于用于构建图谱的种群之间的解剖差异，不能保证图谱之间的解剖对应。因此，本项目的目标是开发一份准确、全面的成人大脑(包括常规脑和骨骼脑)的白质和灰质概率图谱，同时包含多通道、无伪影的解剖MRI和Hardi信息。这项工作的成功完成将带来一套强大的工具，将提高对成人人脑微结构的体素和特定区域研究的准确性。该项目的结果将极大地增强扩散磁共振成像作为一种诊断工具对广泛的临床问题的作用。 公共卫生相关性：扩散磁共振成像提供了关于活体中人脑的微结构完整性和连通性的丰富信息。该项目的目标是开发一份准确、全面的成人大脑白质和灰质数字图谱，同时包含高质量的解剖和弥散磁共振信息。这项工作的成功完成将带来一套强大的工具，这些工具将提高 对成人大脑微结构的体素和特定于脑束的研究。

DESCRIPTION (provided by applicant): Diffusion MRI provides a wealth of information regarding the micro-structural integrity and connectivity of the human brain in vivo. High angular resolution diffusion imaging (HARDI) allows more accurate characterization of complex neuronal micro-architecture than conventional diffusion tensor imaging (DTI), and its once low scanning efficiency has recently become comparable to that of DTI. Therefore, HARDI is rapidly becoming a powerful research and clinical tool. Spatial normalization of HARDI information is necessary in a) whole-brain voxel-wise investigations, b) region-of-interest (ROI) studies comparing the underlying white matter fiber directions, and c) tract-specific HARDI investigations with automated atlas-based tract segmentation. The accuracy of such studies depends on the accuracy of spatial normalization. Accurate spatial normalization requires a high-quality HARDI template representative of the human brain. Study-specific templates can be constructed, but have several limitations. Furthermore, in the case of tract-specific HARDI investigations, accurate tract segmentation also requires that the HARDI template is accompanied by a set of semantic labels accurately delineating different white matter tracts (forming an accurate white matter atlas). Currently available white matter digital atlases are problematic, since they have been either generated based on anatomical landmarks, thus mixing tracts with substantially different roles, or using DTI tractography, which fails in regions with crossing fibers. Therefore, a detailed probabilistic brain atlas is needed, containing a) a high-quality HARDI template representative of the human brain, and b) accurate white matter labels generated with HARDI tractography. Since spatial misalignment can be detrimental in voxel-wise studies of white matter micro-structure, a number of investigations have adopted an alignment-invariant approach where information is first projected onto a white matter "skeleton", followed by voxel-wise analysis on the skeleton. Tract-specific studies using atlas-based segmentation can also be negatively affected by atlas-to-subject misregistration, and could benefit from the alignment-invariant approach if a skeletonized version of an accurate white matter atlas was available. Finally, information on both white and gray matter is often combined in neuroimaging research, and although it is possible to spatially match independently generated white and gray matter atlases, anatomical correspondence between atlases is not guaranteed due to registration errors, as well as due to anatomical differences between the populations used for atlas construction. Therefore, the objective of this project is to develop an accurate, comprehensive white and gray matter probabilistic atlas of the adult human brain (both conventional and skeletonized), also containing multi-channel, artifact-free anatomical MRI and HARDI information. Successful completion of this work will bring forth a powerful set of tools that will increase the accuracy of both voxel-wise and tract-specific investigations of the adult human brain micro-structure. The results of this project will dramatically enhance the role of diffusion MRI as a diagnostic tool for a wide range of clinical problems. PUBLIC HEALTH RELEVANCE: Diffusion MRI provides a wealth of information regarding the micro-structural integrity and connectivity of the human brain in vivo. The objective of this project is to develop an accurate, comprehensive white and gray matter digital atlas of the adult human brain, also containing high-quality anatomical and diffusion MRI information. Successful completion of this work will bring forth a powerful set of tools that will increase the accuracy of both voxel-wise and tract-specific investigations of the adult human brain micro-structure.