Knight Robert A, Han Yuxia, Nagaraja Tavarekere N, Whitton Polly, Ding Jennifer, Chopp Michael, Seyfried Donald M
Henry Ford Hospital, Department of Neurology-NMR Research, 2799 West Grand Blvd, Detroit, MI 48202, USA.
Stroke. 2008 Sep;39(9):2596-602. doi: 10.1161/STROKEAHA.107.506683. Epub 2008 Jul 17.
MRI was used to evaluate the effects of experimental intracerebral hemorrhage (ICH) on brain tissue injury and recovery.
Primary ICH was induced in rats (n=6) by direct infusion of autologous blood into the striatum. The evolution of ICH damage was assessed by MRI estimates of T(2) and T(1sat) relaxation times, cerebral blood flow, vascular permeability, and susceptibility-weighted imaging before surgery (baseline) and at 2 hours and 1, 7, and 14 days post-ICH. Behavioral testing was done before and at 1, 7, and 14 days post-ICH. Animals were euthanized for histology at 14 days.
The MRI appearance of the hemorrhage and surrounding regions changed in a consistent manner over time. Two primary regions of interest were identified based on T(2) values. These included a core, corresponding to the bulk of the hemorrhage, and an adjacent rim; both varied with time. The core was associated with significantly lower cerebral blood flow values at all post-ICH time points, whereas cerebral blood flow varied in the rim. Increases in vascular permeability were noted at 1, 7, and 14 days. Changes in T(1sat) were similar to those of T(2). MRI and histological estimates of tissue loss were well correlated and showed approximately 9% hemispheric tissue loss.
Although the cerebral blood flow changes observed with this ICH model may not exactly mimic the clinical situation, our results suggest that the evolution of ICH injury can be accurately characterized with MRI. These methods may be useful to evaluate therapeutic interventions after experimental ICH and eventually in humans.
采用磁共振成像（MRI）评估实验性脑出血（ICH）对脑组织损伤及恢复的影响。
通过将自体血直接注入大鼠（n = 6）纹状体诱导原发性ICH。在手术前（基线）以及ICH后2小时、1天、7天和14天，通过MRI评估T(2)和T(1sat)弛豫时间、脑血流量、血管通透性以及磁敏感加权成像，以评估ICH损伤的演变。在ICH前以及ICH后1天、7天和14天进行行为测试。在14天时对动物实施安乐死以进行组织学检查。
出血及周围区域的MRI表现随时间呈一致变化。基于T(2)值确定了两个主要感兴趣区域。其中包括一个核心区，对应大部分出血，以及一个相邻的边缘区；两者均随时间变化。核心区在所有ICH后时间点的脑血流量值均显著较低，而边缘区的脑血流量有所变化。在1天、7天和14天时观察到血管通透性增加。T(1sat)的变化与T(2)相似。MRI与组织损失的组织学评估相关性良好，显示半球组织损失约9%。
尽管此ICH模型观察到的脑血流量变化可能无法完全模拟临床情况，但我们的结果表明，MRI能够准确表征ICH损伤的演变。这些方法可能有助于评估实验性ICH后的治疗干预措施，并最终应用于人类。
