Probabilistic White and Gray Matter Atlas of the Adult Human Brain

描述（由申请人提供）：弥散MRI提供了关于人体大脑微观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）更准确地表征复杂的神经元微结构，其曾经低的扫描效率最近已经可以与DTI相媲美。因此，HARDI正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以下方面是必要的：1)全脑体素调查；2)感兴趣区域（ROI）研究，比较潜在的白质纤维方向；3)基于自动图谱的束分割的特定束HARDI调查。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，但有一些限制。此外，在特定神经束的HARDI研究中，准确的神经束分割还需要HARDI模板附带一组准确描述不同白质束的语义标签（形成准确的白质图谱）。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标志生成的，从而混合了具有本质不同作用的脑束，要么是使用DTI脑束成像，这在某些区域是失败的

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.