兔局灶性脑缺血/再灌注损伤后脑水肿的系列MRI动态演变

目的研究兔局灶性脑缺血/再灌注损伤后脑水肿的系列MRI动态演变.方法健康新西兰白兔27只,随机分为两组:A组5只,为假手术组;B组22只,为线栓法局灶性脑缺血/再灌注模型组.于缺血3 h/再灌注后1 h(4只)、3 h、6 h、12 h、1天、3天、7天(各3只)行头颅MR 扫描,扫描序列包括T1WI、T2WI、液体衰减反转恢复(FLAIR)、弥散加权成像(DWI)及强化后T1WI扫描,观察缺血再灌注后脑组织T2WI、DWI及强化后T1WI信号参数的改变.结果缺血3 h/再灌注后MRI可见左侧大脑半球颞顶叶及外侧基底节异常信号.缺血3 h/再灌注后1天内左侧大脑半球病变T2信号强度逐渐增加,随后开始下降,而表观弥散系数(ADC)的变化与此相反.结论兔局灶性脑缺血/再灌注后脑水肿是血管源性水肿与细胞毒性水肿共同作用的表现,而且血管源性水肿与血脑屏障破坏的关系密切.

Dynamic changes of cerebral edema explored by serial MRI in focal cerebral ischemia/reperfusion model of rabbits

Objective To explore the dynamic changes of cerebral edema by serial MRI in focal cerebral ischemia/reperfusion model of rabbit.Methods Twenty-seven New Zealand white rabbits were randomly divided into two groups: Group A(n=5) was sham-operated.In group B(n=22),the focal cerebral ischemia/reperfusion model was made.MRI was performed 1 h(n=4),3 h,6 h,12 h,1 day,3 days,and 7 days(n=3),respectively after reperfusion,the sequences including T1WI,T2WI,fluid-attenuated inversion recovery,diffusion-weighted imaging and post-contrast T1WI.The signal changes of T2WI,diffusion-weighted imaging and post-contrast T1WI were observed.Results MRI showed the abnormal signal in left temporal,parietal lobe and basal ganglia.The signal on T2WI increased in 1 day,and then declined,but the change of apparent diffusion coefficient was on the contrary.Conclusion The appearance of cerebral edema after reperfusion was the effect of both vasogenic and cytotoxic edema.And the vasogenic edema was associated closely with blood-brain barrier disruption.