Diffusion time dependence of the apparent diffusion tensor in healthy human brain and white matter disease
Diffusion time dependence of the apparent diffusion tensor in healthy human brain and white matter disease
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DOI：
10.1002/mrm.1149
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发表时间：
2001-06-01
影响因子：
3.3
通讯作者：
Moseley, ME
中科院分区：
文献类型：
--
作者：
Clark, CA;Hedehus, M;Moseley, ME
脑水扩散张量的扩散时间依赖性提供了关于扩散限制和阻碍的信息，但很少受到关注，主要是由于临床MRI系统上可用的梯度幅度的限制，需要实现短的扩散时间。使用新的更强大的梯度硬件，在人脑中研究了张量导出的度量的扩散时间依赖性，范围为8-80 ms，这包括迄今为止研究的最短扩散时间。没有证据表明平均扩散率、各向异性分数或特征值随健康人脑扩散时间的变化。这些发现与半透膜不受限制但受阻碍的水扩散模型一致，可能源自细胞外间隙，其中平均细胞外分离小于7微米。在两个多发性硬化斑块中的类似发现表明，病变中的水扩散空间的尺寸不超过该尺寸，（C）2001 Wiley-Liss，Inc.
The diffusion time dependence of the brain water diffusion tenser provides information regarding diffusion restriction and hindrance but has received little attention, primarily due to limitations in gradient amplitude available on clinical MRI systems, required to achieve short diffusion times, Using new, more powerful gradient hardware, the diffusion time dependence of tenser-derived metrics were studied in human brain in the range 8-80 ms, which encompasses the shortest diffusion times studied to date. There was no evidence for a change in mean diffusivity, fractional anisotropy, or in the eigenvalues with diffusion time in healthy human brain. The findings are consistent with a model of unrestricted, but hindered water diffusion with semipermeable membranes, likely originating from the extracellular space in which the average extracellular separation is less than 7 microns. Similar findings in two multiple sclerosis plaques indicated that the sire of the water diffusion space in the lesion did not exceed this dimension, (C) 2001 Wiley-Liss, Inc.