Shen Qiang, Huang Shiliang, Duong Timothy Q
Research Imaging Institute, University of Texas Health Science Center, San Antonio, 8403 Floyd Curl Dr, TX 78229, United States; Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, United States.
Research Imaging Institute, University of Texas Health Science Center, San Antonio, 8403 Floyd Curl Dr, TX 78229, United States.
Brain Res. 2015 Mar 2;1599:126-36. doi: 10.1016/j.brainres.2014.12.049. Epub 2014 Dec 31.
Cerebral blood flow (CBF) is tightly coupled to metabolism and neural activity under normal physiological conditions, and is often perturbed in disease states. The goals of this study were to implement a high-resolution (up to 50×38μm(2)) CBF MRI protocol of the rat brain, create a digital CBF atlas, report CBF values for 30+ brain structures based on the atlas, and explore applications of high-resolution CBF fMRI of forepaw stimulation. Excellent blood-flow contrasts were observed among different cortical and subcortical structures. CBF MRI showed column-like alternating bright and dark bands in the neocortices, reflecting the layout of descending arterioles and ascending venules, respectively. CBF MRI also showed lamina-like alternating bright and dark layers across the cortical thicknesses, consistent with the underlying vascular density. CBF profiles across the cortical thickness showed two peaks in layers IV and VI and a shallow trough in layer V. Whole-brain CBF was about 0.89ml/g/min, with the highest CBF values found amongst the neocortical structures (1ml/g/min, range: 0.89-1.16ml/g/min) and the lowest CBF values in the corpus callosum (0.32ml/g/min), yielding a gray:white matter CBF ratio of 3.1. CBF fMRI responses peaked across layers IV-V, whereas the BOLD fMRI responses showed a peak in the superficial layers II-III. High-resolution basal CBF MRI, evoked CBF fMRI, and CBF brain atlas can be used to study neurological disorders (such as ischemic stroke).
在正常生理条件下，脑血流量（CBF）与代谢和神经活动紧密耦合，而在疾病状态下常受到干扰。本研究的目的是实施一种大鼠脑高分辨率（高达50×38μm²）的CBF MRI方案，创建一个数字化CBF图谱，基于该图谱报告30多个脑结构的CBF值，并探索前爪刺激的高分辨率CBF功能磁共振成像的应用。在不同的皮质和皮质下结构中观察到了出色的血流对比。CBF MRI显示新皮质中有柱状的明暗交替带，分别反映了下行小动脉和上行小静脉的布局。CBF MRI还显示了跨皮质厚度的层状明暗交替层，与潜在的血管密度一致。跨皮质厚度的CBF剖面图显示在IV层和VI层有两个峰值，在V层有一个浅谷。全脑CBF约为0.89ml/g/min，新皮质结构中的CBF值最高（1ml/g/min，范围：0.89 - 1.16ml/g/min），胼胝体中的CBF值最低（0.32ml/g/min），灰质与白质的CBF比值为3.1。CBF功能磁共振成像反应在IV - V层达到峰值，而血氧水平依赖性功能磁共振成像反应在浅表的II - III层出现峰值。高分辨率基础CBF MRI、诱发的CBF功能磁共振成像和CBF脑图谱可用于研究神经系统疾病（如缺血性中风）。
