2型糖尿病大鼠超急性期脑缺血半暗带演变的MRI研究

Evolution of Cerebral Ischemic Penumbra at Superacute Phase in DM2 Rats:An MRI Study

目的探究2型糖尿病大鼠脑梗死后超急性期缺血半暗带(ischemic penumbra,IP)随时间变化趋势。材料与方法 2型糖尿病大鼠及血糖正常对照组大鼠各9只,制作永久性大脑中动脉闭塞(MCAO)模型,MCAO后30min、1 h、3 h、6 h、9 h、12 h分别行MR扩散加权成像(DWI)、扩散张量成像(DTI)及T2WI,测量并计算病灶核心区及边缘区的相对表观扩散系数(rADC)值,相对平均扩散系数(rDCavg)值、相对各向异性分数(rFA)值。结果 2型糖尿病大鼠脑缺血后3 h以内、血糖正常大鼠9 h以内,缺血边缘区与核心区之间rADC、rDCavg值差异存在统计学意义(P<0.05)。结论血糖正常大鼠脑IP存在的时间窗为9 h;2型糖尿病大鼠脑IP存在的时间窗<3 h。缺血前高血糖加速脑缺血后血管源性水肿的发展。

Objective To study the evolution of cerebral ischemic penumbra at superacute phase in DM2 Rats.Materials and Methods Nine DM2 rats and nine normal rats were operated to develop MCAO model.MRI scan including diffusion weighted imaging（DWI）,diffusion tensor imaging（DTI）,T2-weighted imaging（T2WI）were performed at 30 min,1h,3h,6h,9h,12h respectivelly after MCAO.The apparent diffusion coefficient（ADC）,average diffusion coefficient（DCavg）,fractional anisotropy（FA） were measured in the central and peripheric area of ischemia lesions to calculate relative ADC（rADC）,relative DCavg（rDCavg）,relative FA（rFA）.Results For normal rats,rADC and rDCavg had significant difference between core and margin at 3h after MCAO.For DM2 rats,rADC and rDCavg had significant difference between core and margin at 9h after MCAO.Conclusion The time window of IP is about 9 hours in normal rats,and 3 hours in DM2 rats.Hyperglycemia before ischemia accelerated the process of vasogenic edema.