Bartnik B L, Kendall E J, Obenaus A
Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, 107 Wiggins Road, SK S7N 5E5, Saskatoon, Canada.
Brain Res. 2001 Oct 12;915(2):133-42. doi: 10.1016/s0006-8993(01)02805-0.
This study investigates the development of a small focal cortical lesion produced in a model of brain injury. Two approaches were chosen: diffusion weighted magnetic resonance imaging (DWI) and histology. DW images were collected before devascularization and at 0.5, 1, 2, 3, 5, 7 and 14 days after treatment. Apparent diffusion coefficient (ADC) maps were calculated from the DW images to quantify lesion development. As a second measure of injury, tissue morphology was analyzed using cresyl violet histochemistry. A significant reduction in ADC values within the cortex below the injury site by 0.5 days after surgery was observed. Between 5 and 14 days the ADC values recovered to control levels. ADC changes were also observed in the contralateral cortex at 0.5, 1 and 5 days. The decrease in ADC observed at the early time points suggested cytotoxic edema, whereas the recovery to control levels at later time points suggested infarct formation. This model of brain injury resulted in progressive but relatively slow formation of a pan-necrotic infarct within 14 days. In particular, substantial amounts of cell death were not observed until 2 days after surgery. Overall, the quantitative and histological measures of this lesion are consistent with those observed for an ischemic type of injury, however, the time course of these lesions' development are consistent with other models of traumatic brain injury. Our data demonstrates that DWI is a highly sensitive metric for ischemic-type damage that results from brain injury.
本研究调查了脑损伤模型中产生的小灶性皮质病变的发展情况。选择了两种方法：扩散加权磁共振成像（DWI）和组织学。在血管闭塞前以及治疗后0.5、1、2、3、5、7和14天采集DWI图像。从DWI图像计算表观扩散系数（ADC）图以量化病变发展。作为损伤的第二种测量方法，使用甲酚紫组织化学分析组织形态。术后0.5天观察到损伤部位下方皮质内的ADC值显著降低。在5至14天之间，ADC值恢复到对照水平。在0.5、1和5天也观察到对侧皮质的ADC变化。早期时间点观察到的ADC降低提示细胞毒性水肿，而后期时间点恢复到对照水平提示梗死形成。这种脑损伤模型在14天内导致全坏死性梗死逐渐但相对缓慢地形成。特别是，直到术后2天才观察到大量细胞死亡。总体而言，该病变的定量和组织学测量结果与缺血性损伤观察到的结果一致，然而，这些病变发展的时间进程与其他创伤性脑损伤模型一致。我们的数据表明，DWI是脑损伤导致的缺血性损伤的高度敏感指标。
