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目的 应用弥散 -灌注磁共振成像技术对改良线栓法建立的超急性脑梗死再灌注模型进行实验研究。明确该技术对超急性脑梗死再灌注的评价作用。方法 90只SD大鼠 ,随机分成 5组 ,A组 ( 10只 )假手术做对照 ,其余按栓塞时间 3 0min、1、3、6h均分成B、C、D、E 4组 ;行DWI、PI和常规T2 WI、T1WI扫描 ;DWI和PI原始图像重建获得ADC、CBV、CBF、MTT参数形态图。观察各栓塞时间点再灌注 2、2 4h后各项参数变化。结果 A组DWI、PI成像无异常信号。B组再灌注 2hDWI高信号消失 ,ADC值恢复正常化 ( 88.2 7%± 1.92 % ) ,2 4h继发性ADC值降低和DWI高信号 ;C组再灌注 2h后ADC值轻度升高 ,2 4h明显降低 ;D、E组再灌注 2、2 4hADC值轻度降低或基本不变 ;各组再灌注后 2 4hDWI显示病灶范围无明显扩大。A、B组再灌注后PI各参数指标 (CBV、CBF、MTT)恢复和维持正常 ,而D、E组的信号强度 -时间曲线图有 3种表现 ,分别为高灌注、低灌注和正常灌注。结论 在超急性脑梗死中MCAo 3 0min再灌注后初次DWI异常信号消散是暂时的 ,以后会发生继发性DWI异常信号 ;再灌注可限制病灶进一步扩大 ,保护缺血半影区
Objective To study the model of hyperacute cerebral infarction reperfusion established by modified suture method with diffusion-perfusion magnetic resonance imaging. Clear the technology of hyperacute cerebral infarction reperfusion evaluation. Methods Ninety Sprague-Dawley rats were randomly divided into five groups. Group A (n = 10) were sham-operated. The rest were divided into groups B, C, D and E 4 according to the embolization time of 30 min, PI and conventional T2WI, T1WI scan. DWI and PI original image reconstruction ADC, CBV, CBF, MTT parameters morphology. The changes of parameters after 2,22 hours of reperfusion at each embolization point were observed. Results A group of DWI, PI imaging no abnormal signal. In group B, the high signal disappeared after 2h DWI, the ADC value returned to normal (88.2 7% ± 1.92%), the secondary ADC value decreased and DWI high signal was detected at 24 hours. The ADC value increased slightly 2 hours after reperfusion in group C 4h significantly reduced; D, E group 2,2 4hADC reperfusion slightly decreased or almost unchanged; 24HDWI after reperfusion in each group showed no significant enlargement of the lesion range. The indexes of PI (CBV, CBF, MTT) in group A and group B recovered and remained normal after reperfusion, while the signal intensity-time curves in group D and group E showed three kinds of performance: high perfusion, low perfusion and normal perfusion . Conclusions The first DWI abnormal signal dissipation after transient MCA was resuscitated at 30 min in hyperacute infarction was transient, and secondary abnormal signal of DWI occurred later. Reperfusion could limit further enlargement of the lesion and protect the ischemic penumbra