Oscillating gradient measurements of water diffusion in normal and globally ischemic rat brain
Oscillating gradient measurements of water diffusion in normal and globally ischemic rat brain
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DOI：
10.1002/mrm.10385
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发表时间：
2003-02-01
影响因子：
3.3
通讯作者：
Gore, JC
中科院分区：
文献类型：
--
作者：
Does, MD;Parsons, EC;Gore, JC
使用振荡梯度来探测正常和全局缺血大鼠脑灰质中水扩散的扩散时间/频率依赖性。根据扩散时间的传统定义，振荡梯度测量提供了水的表观扩散系数（ADC），其扩散时间在 9.75 ms 至 375 mus 之间，比之前在体内研究的要短一个数量级。在此范围内，ADC 在体内增加了 24%，在死后增加了 50%，具体取决于所使用的振荡梯度波形的性质。采用新颖的波形对所谓的扩散频谱的窄频带进行采样。 ADC 的光谱描述包括限制和/或流量的影响，并且独立于实验参数，例如扩散时间。大鼠大脑中的结果被发现与限制扩散和已知的灰质微观解剖结构一致。正常和死后数据之间的差异与水限制的增加和/或流量的减少一致，并初步表明缺血发生后的物理变化发生在约2μm的范围内，类似于灰质中的典型细胞尺寸。 (C) 2003 Wiley-Liss, Inc.
Oscillating gradients were used to probe the diffusion-time/ frequency dependence of water diffusion in the gray matter of normal and globally ischemic rat brain. In terms of a conventional definition of diffusion time, the oscillating gradient measurements provided the apparent diffusion coefficient (ADC) of water with diffusion times between 9.75 ms and 375 mus, an order of magnitude shorter than previously studied in vivo. Over this range, ADCs increased as much as 24% in vivo and 50% postmortem, depending on the nature of the oscillating gradient waveform used. Novel waveforms were employed to sample narrow frequency bands of the so-called diffusion spectrum. This spectral description of ADC includes the effects of restriction and/or flow, and is independent of experimental parameters, such as diffusion time. The results in rat brain were found to be consistent with restricted diffusion and the known micro-anatomy of gray matter. Differences between normal and postmortem data were consistent with an increase in water restriction and/or a decrease in flow, and tentatively suggest that physical changes following the onset of ischemia occur on a scale of about 2 mum, similar to a typical cellular dimension in gray matter. (C) 2003 Wiley-Liss, Inc.