Huang Hao, Vasung Lana
Advanced Imaging Research Center, Johns Hopkins University, United States; Department of Radiology, University of Texas Southwestern Medical Center, Johns Hopkins University, United States; Department of Radiology, Johns Hopkins University, United States.
Croatian Institute for Brain Research, University of Zagreb, Croatia.
Int J Dev Neurosci. 2014 Feb;32:11-22. doi: 10.1016/j.ijdevneu.2013.06.005. Epub 2013 Jun 21.
Human brain is extraordinarily complex and yet its origin is a simple tubular structure. Its development during the fetal period is characterized by a series of accurately organized events which underlie the mechanisms of dramatic structural changes during fetal development. Revealing detailed anatomy at different stages of human fetal brain development provides insight on understanding not only this highly ordered process, but also the neurobiological foundations of cognitive brain disorders such as mental retardation, autism, schizophrenia, bipolar and language impairment. Diffusion tensor imaging (DTI) and histology are complementary tools which are capable of delineating the fetal brain structures at both macroscopic and microscopic levels. In this review, the structural development of the fetal brains has been characterized with DTI and histology. Major components of the fetal brain, including cortical plate, fetal white matter and cerebral wall layer between the ventricle and subplate, have been delineated with DTI and histology. Anisotropic metrics derived from DTI were used to quantify the microstructural changes during the dynamic process of human fetal cortical development and prenatal development of other animal models. Fetal white matter pathways have been traced with DTI-based tractography to reveal growth patterns of individual white matter tracts and corticocortical connectivity. These detailed anatomical accounts of the structural changes during fetal period may provide the clues of detecting developmental and cognitive brain disorders at their early stages. The anatomical information from DTI and histology may also provide reference standards for diagnostic radiology of premature newborns.
人类大脑极其复杂，但其起源却是一个简单的管状结构。胎儿期大脑的发育以一系列精确组织的事件为特征，这些事件构成了胎儿发育过程中显著结构变化机制的基础。揭示人类胎儿大脑发育不同阶段的详细解剖结构，不仅有助于理解这一高度有序的过程，还能洞察诸如智力迟钝、自闭症、精神分裂症、双相情感障碍和语言障碍等认知性脑部疾病的神经生物学基础。扩散张量成像（DTI）和组织学是互补的工具，能够在宏观和微观层面描绘胎儿大脑结构。在本综述中，利用DTI和组织学对胎儿大脑的结构发育进行了表征。胎儿大脑的主要组成部分，包括皮质板、胎儿白质以及脑室和亚板之间的脑壁层，已通过DTI和组织学进行了描绘。从DTI得出的各向异性指标用于量化人类胎儿皮质发育动态过程以及其他动物模型产前发育过程中的微观结构变化。利用基于DTI的纤维束成像技术追踪胎儿白质通路，以揭示各个白质束的生长模式和皮质间连接。这些关于胎儿期结构变化的详细解剖描述可能为在早期阶段检测发育性和认知性脑部疾病提供线索。来自DTI和组织学的解剖学信息也可为早产儿的诊断放射学提供参考标准。
