脑缺血再灌注大鼠模型FAIR-PWI研究

Flow Sensitive Alternating Inversion Recovery PerfusionWeighted Imaging in Acute Brain Ischemia and Early Reperfusion of Rats

目的:探讨流动敏感交替反转恢复序列灌注成像(FAIR-PWI)对大鼠脑缺血后再灌注的评价。方法:使用GE 3.0T M RI成像仪,在完成T_1WI、T_2 WI、弥散加权成像(DWI)和FAIR-PWI序列后,对SD大鼠行暂时性右侧大脑中动脉闭塞(TMCA0)手术,分别在脑缺血3h和再灌注3h及21h行重复上述MRI检查;最后进行病理学TTC染色观察梗死区域及范围。结果:TMCAO后3h时,患侧大脑半球DWI信号升高、FAIR-PWI灌注增加、且皮质相对脑血流量(rCBF)大于基底节区;再灌注3h及21h后,患侧大脑半球DWI信号面积(0.63±0.12cm^2、0.48±0.23cm^2)仍高于FAIR-PWI高灌注面积(0.51±0.26cm^2、0.34±0.44cm^2,P=0.01),皮质及基底节区rCBF较缺血时增加。TTC染色示梗死面积(0.42±0.78cm^2)小于DWI异常信号面积,而大于FAIR-PWI高灌注面积,且梗死区以基底节为主。结论:FAIR-PWI结合DWI能对早期缺血再灌注进行动态观察及半定量测量,可能为临床溶栓治疗方案的预后判断和随访提供重要参考,

Purpose： To evaluate the value of flow sensitive alternating inversion recovery perfusion weighted imaging （FAIR - PWI） in cerebral ischemia and reperfusion of rats. Methods： Firstly, SD rats underwent MRI scan including TlWI, T2WI, diffusion weighted imaging（DWI） and FARI - PWI on a 3.0T machine. Then right side cerebral ischemic model of transient middle cerebral artery occlusion （TMCAO） was operated on rats, and 3 hours later previous MR imaging was repeated. After that, the nylon embolus were extracted for reperfusion, 3 hours and 21 hours after reperfusion the same MRI exam was per- formed repeatedly. Lastly, rats were sacrificed for TTC staining, and the infarction size was measured. Results： At 3h after TMCAO, signal intensity of affected side on DWI and FAIR - PWI was increased, and cortical perfusion was higher than basal ganglia perfusion. At 3h and 21h after reperfusion, the size of lesion area on DWI were still larger （0.63 ± 0.12cm2, 0.48 ± 0.23cm2） than that on FAIR - PWI （0.51 ±0.26cm2 ,0.34±0.44cm2, P =0. 0103, P = 0. 0129） ; both cortical perfusion and basal ganglia perfusion were higher than those during ischemic phase. Lastly, the size of infarct area on TTC stain （0.42 ±0.78 cm2） was less than that of DWI, but larger than that of FAIR - PWI, and the infarct areas were mostly located at basal ganglia. Conclusion： As a noninvasive method, combined with DWI, FAIR - PWI can dynami- cally detect early ischemia and reperfusion without administration of contrast media, which may provide important information for thrombolysis therapy and follow up.