超急性与急性期脑缺血半暗带演变的DWI研究

目的测定超急性与急性期缺血性脑梗死患者扩散加权成像病变区和周围区ADC值以观测半暗带的存在形式和演变过程。方法测量67例次超急性期与急性期缺血性脑梗死的DWI图像高信号区和其周围区ADC值,对于超早期脑梗死患者均行MRI随诊至发病48h以后。对数据依时间分组进行统计学分析。结果DWI高信号区的ADC值均较对侧相应部位ADC值减低。病变中心区ADC值减低最明显。病变中心至周边ADC值呈由低到高不同程度的增加。病变外周区域ADC值也较对侧轻度减低。结论①缺血的超急性、急性期病灶的周边区有缺血半暗带,且这一时间窗在缺血后的24h内都可能存在。②病变范围不断扩大的过程中DWI高信号的外周区域也存在半暗带。病变运动相对静止后,部分外周扩散轻度异常区代表良性缺血区。

Diffusion-weighted imaging evolution of brain ischemia penumbra in hyperacute and acute stages

Objective To study the role of DWI in hyperacute and acute stages of cerebral infarction and to identify the present time window and range and ischemic penumbra. Methods Sixty-seven patients with hyperacute and acute cerebral infarction were divided six groups according to the time of attack. Parameters measured apparent diffusion coefficient (ADC) in the DWI high signal intensity region and normal signal intensity just adjacent to high signal intensity. Statistical analysis was performed by SPSS 11.0 software package, t-test and ANOVA analysis were used within each group and among different groups. Results The degree of decreasing in infarct margin was lower than that in infarct core. The ADC value in infarct periphery was slightly lower than that of normal brain tissue. Conclusion In hyperacute and acute cerebral infarction, the diffusion of water molecule was remarkably lower than that in normal brain tissue, but it was different between infarct core and infarct margin. In acute cerebral infarction, there were significant differences of the diffusion-limited degree between infarct core and infarct margin, suggesting infarct margin may be ischemic penumbra. And the time window may be until 24 h.