弥散张量成像预测兔超急性期脑梗死后出血

目的 探讨脑梗死超急性期弥散张量成像(DTI)对兔脑梗死后出血(HT)的预测作用.方法 35只兔经颈内动脉插管注入自体血栓建立急性血栓性脑梗死模型.术后3 h常规MR检查,证实为脑梗死后行兔脑冠状面DTI,72 h后处死动物、取脑,观察大体标本及显微镜下梗死区有无出血及其程度,比较HT组与无HT组、有HT动物的HT区与非HT区、HI与PH区DTI参数变化差异.结果 26只动物(74.29%)模型制作成功.无HT者8只(30.77%,8/28)、HT者18只(69.23%,18/26),HT组包括HI组14只(53.85%)及PH组4只(15.38%).HT组与非HT组T2加权示踪(T2WT)、平均扩散系数(DCavg)、各向异性系数(FA)、容积比(1-VR)、指数衰减(EA)均有明显差异(P<0.001～P=0.039).有HT动物的HT区与非HT区的T2WT、DCavg、FA、及EA值差异显著(P<0.001),1-VR值无明显差别.HI组与PH组HT区DTI各参数无显著差异(P>0.05).结论 DTI有可能预测兔脑梗死后是否继发出血.

Diffusion tensor imaging in superacute stage in predication of hemorrhagic transformation after acute autologous emboli cerebral infarction in rabbits

Objective To assess the value of diffusion tensor imaging (DTI) in superacute stage in predication of hemorrhagic transformation (HT) of acute cerebral infarction in rabbits. Methods Autologous emboli were injected into internal carotid arteries of 35 rabbits to set up acute embolic cerebral infarction model. When infarction was confirmed by conventional MR imaging at 3 hours after operation, DTI in coronal plane was made. The animals were executed at 72 h. Six sections of rabbit brain with a thickness of 3 mm were made in correspondence with MRI. The HT of infarcted animals were classified into hemorrhagic infarction (HI) and parenchymal hematoma (PH) group according to the method of European-Astralilasian acute stroke study (ECASS). DTI parameters between HT group and non-HT group, HT area and non-HT area, HI lesions and PH lesions were compared. Results Cerebral ischemic model was successfully set up to 26 rabbits (74.29%). No pathologic findings of HT was found for 8 animals (30.77%, 8/26). Findings of 18 rabbits (69.23%, 18/26) of HT included 14 rabbits (53.85%) with HI and 4 (15.38%) with PH were analyzed. There were significant difference (P<0.001-P=0.039) of value of T2-weighted trace (T2WT), average diffusion coefficient (DC_avg), fractional aniso (FA), volume ration aniso (1-VR), exponential attenuation (EA) between HT group and non-HT group. There were also prominent difference of the value of T2WT, DC_avg, FA and EA between HT areas and non-HT areas (P<0.001), whereas no significant difference for 1-VR value was found between them, nor for parameters between HI and PH groups (P>0.05). Conclusion DTI at 3 h after acute cerebral infarction probably may predict the occurrence of HT.