摘要
目的利用MRI技术研究大鼠脑缺血模型的超急性期(6 h内)及急性期影像动态演变规律。方法 10只Wistar雄性大鼠,采用线栓法制作右侧大脑中动脉栓塞(MCAO)缺血模型,分别于MCAO后0.5、2、6、12和24 h行大鼠脑部冠状位磁共振T_1WI、T_2WI及弥散加权成像(DWI)扫描,分别测量T_2WI及表观弥散系数(ADC)图像上缺血区异常信号体积、ADC值和相对ADC值(rADC),并进行分析。结果随缺血时间延长,DWI及T_2WI异常高信号体积持续增大。0.5、2、6、12和24 h各时间点ADC图像显示的脑缺血体积明显大于T_2WI(P<0.01)。缺血中心区和边缘区的ADC值均较对侧脑组织明显减低(P<0.01)。随缺血时间延长,缺血中心区、边缘区和外周区的rADC值均呈不同程度减低。缺血中心区MCAO后2、6、12和24 h的rADC值明显低于0.5 h(P<0.01);缺血边缘区MCAO后2、6、12和24 h的rADC值明显低于0.5 h(P<0.01),6 h的rADC值明显低于2 h(P<0.05),12和24 h的rADC值明显低于2 h(P<0.01),24 h的rADC值明显低于6 h(P<0.05)。结论大鼠超急性期脑缺血病变进展迅速,急性期脑缺血进展减慢,DWI检查有助于早期诊断缺血半暗带。
Objective To investigate the dynamic evolution of magnetic resonance images in the hyperacute and acute phases of cerebral infarction of acute cerebral ischemia rat model. Methods Ten male Wistar rats were used to establish right middle cerebral artery occlusion model （MCAO）. Diffusion weighted imaging（DWI）,T2WI and T^WI were performed 0.5 h,2 h,6 h,12 h and 24 h after MCAO. The value of apparent diffusion coefficient（ADC） and the infarction volume on T2 WI and ADC map were measured. Results The intensity and volume of abnormal high signal on DWI and T2 WI gradually increased over time. The infarct volume on ADC map was significantly larger than that on T2WI at each time point （P 〈 0.01）. The ADC values of the infarct center and infarcted edge region were significantly decreased compared with the corresponding contralateral region （P 〈 0.01）. The relative ADC（rADC） values of the infarct center,infarcted edge and infarcted peripheral region were decreased over time. The rADC values of both infarct center and infarcted edge had significant differences among examinations at different time points after MCAO （P 〈 0.05）. However,the ADC value in the infarcted peripheral region had no sig- nificant differences among examinations at different time points after MCAO （P 〉 0.05）. Conclusion Cerebral ischemia develops rapidly in hyperacute phase and slowly during acute phase. DWI could demonstrate the ischemic penumbra within 24 hours.
出处
《中华老年心脑血管病杂志》
CAS
北大核心
2011年第8期689-692,共4页
Chinese Journal of Geriatric Heart,Brain and Vessel Diseases
基金
国家自然科学基金(30900365)
北京市自然科学基金(7092038)
关键词
脑缺血
磁共振成像
弥散
模型
动物
早期诊断
brain ischemia
diffusion magnetic resonance imaging
models, animal
early diagnosis
