MRI弥散张量成像预测兔急性缺血性脑卒中出血性转化的价值

Value of MRI diffusion tensor imaging to predicting hemorrhagic transiormation in rabbits with acute ischemic stroke

目的探讨3.0 T MRI弥散张量成像(diffusion tensor imaging,DTI)各向异性系数(fractional anisotropy,FA)在兔急性缺血性脑卒中出血性转化(hemorrhagic transformation,HT)预测中的价值。方法新西兰大白兔43只,随机分为手术组(33只)和假手术组(10只),手术组采用自体血栓法制备急性缺血性脑卒中模型,假手术组应用生理盐水代替自体血栓;手术组于模型制备成功后4 h应用尿激酶行静脉溶栓治疗,假手术组不作处理。2组分别于造模后3 h及溶栓治疗后2、12及24 h行DTI及MRI磁敏感加权成像(susceptibility weighted imaging,SWI)检查,依据末次SWI扫描是否发现缺血区域内低信号将手术组分为HT组(8只)和无HT组(25只),比较各组不同时间点FA值差异。结果假手术组术后均无行为障碍,MRI均未见异常;手术组麻醉苏醒后出现不同程度行为障碍;HT组造模后3 h及溶栓治疗后2、12及24 h FA值(0.143±0.017、0.126±0.018、0.136±0.017、0.141±0.017)低于无HT组(0.403±0.070、0.246±0.037、0.217±0.037、0.202±0.035)和假手术组(0.429±0.066、0.428±0.069 0.431±0.066、0.433±0.070)(P<0.05);无HT组溶栓后2、12及24h FA值低于假手术组(P<0.05),造模后3 h FA值与假手术组差异无统计学意义(P>0.05)。结论兔急性脑缺血性脑卒中后发生HT可能与FA值降低有关。

Objective To explore the value of fractional anisotropy(FA) of diffusion tensor imaging(DTI) to predicting hemorrhagic transformation(HT) after acute ischemic stroke in rabbits.Methods Forty-three New Zealand white rabbits were randomly divided into operation group(n=33) and sham operation group(n=10).In operation group,the cerebral ischemia models were prepared by the method of autologous thrombus,and sham operation group received normal saline instead of autologous thrombus.Operation group received urokinase intravenous thrombolysis in 4 h after model establishment,and sham operation group was not treated.Both groups underwent MRI in 3h after model establishment,and 2,12 and 24 h after thrombolysis.DTI and susceptibility-weighted imaging were performed in 24 h after thrombolysis.According to the last SWI result,operation group was divided into HT group(n = 8) with low signal in ischemic area and non-HT group(n=25) without low signal in ischemic area.The differences of FA values in each group were compared at different time points.Results All rabbits in sham operation group had no obvious behavior disorders or MRI abnormalities after operation.In operation group,all had behavior disorders in different degrees after anesthesia awakening.The FA values in 3 h after model establishment(0.143±0.017),and 2,12 and 24 h after thrombolysis(0.126±0.018,0.136±0.017,0.141±0.017) in HT group were significantly lower than those in non-HT group(0.403±0.070,0.246±0.037,0.217±0.037,0.202±0.035) and sham operation group(0.429±0.066,0.428±0.069,0.431±0.066,0.433±0.070)(P<0.05).The FA values in 2,12 and 24 h after thrombolysis were significantly lower in non-HT group than those in sham operation group(P<0.05),and there was no significant difference in 3 h after model establishment between two groups(P>0.05).Conclusion The decrease of FA might be involved in the occurrence of HT after acute ischemic stroke in rabbits.