Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY 10016, USA.
NMR Biomed. 2010 Aug;23(7):821-35. doi: 10.1002/nbm.1579.
Integration of the neural processes in the human brain is realized through interconnections that exist between different neural centers. These interconnections take place through white matter pathways. White matter tractography is currently the only available technique for the reconstruction of the anatomical connectivity in the human brain noninvasively and in vivo. The trajectory and terminations of white matter pathways are estimated from local orientations of nerve bundles. These orientations are obtained using measurements of water diffusion in the brain. In this article, the techniques for estimating fiber directions from diffusion measurements in the human brain are reviewed. Methods of white matter tractography are described, together with the current limitations of the technique, including sensitivity to image noise and partial voluming. The applications of white matter tractography to the topographical characterization of the white matter connections and the segmentation of specific white matter pathways, and corresponding functional units of gray matter, are discussed. In this context, the potential impact of white matter tractography in mapping the functional systems and subsystems in the human brain, and their interrelations, is described. Finally, the applications of white matter tractography to the study of brain disorders, including fiber tract localization in brains affected by tumors and the identification of impaired connectivity routes in neurologic and neuropsychiatric diseases, are discussed.
人类大脑中的神经过程通过不同神经中枢之间的连接实现整合。这些连接通过白质通路发生。目前，在不进行有创性和体内操作的情况下，对人脑进行解剖连接的重建，唯一可用的技术是白质束追踪技术。白质束追踪技术是从神经束的局部方向估计白质通路的轨迹和终点。这些方向是通过测量大脑中的水分子扩散获得的。本文回顾了从人脑扩散测量中估计纤维方向的技术。描述了白质束追踪方法，以及该技术的当前局限性，包括对图像噪声和部分容积效应的敏感性。讨论了白质束追踪在描绘白质连接的拓扑特征和特定白质通路以及相应的灰质功能单位，以及相应的功能单元的应用。在这种情况下，描述了白质束追踪在绘制人类大脑中的功能系统和子系统及其相互关系中的潜在影响。最后，讨论了白质束追踪在脑疾病研究中的应用，包括受肿瘤影响的大脑中的纤维束定位以及在神经和神经精神疾病中识别受损的连接路径。
