急性脑缺血及再灌注的DWI与PWI实验研究

Experimental study of DWI and PWI in acute cerebral ischemia - reperfusion

目的利用DWI及PWI研究大鼠(MCAO)急性脑缺血再灌注模型,观察脑缺血再灌注的动态变化规律,探讨急性脑缺血的发病机理。方法建立大鼠急性脑缺血再灌注模型,45只雄性SD大鼠(280～320g),随机分成3组(A、B、C组,n=15)。单丝尼龙线置入颈内动脉,阻闭右侧大脑中动脉。分别于阻闭30min、1h、2h后抽出尼龙线,恢复再灌注。于再通前,再通后1h、2h、3h、6h、12h及24h行功能及常规磁共振扫描。对3组结果进行比较分析。结果(1)A组再通后较再通前DWI所示高信号区明显缩小,B组再通后较再通前不同程度缩小,C组再通后均较前略有扩大。3组间差异显著(P<0.01)。(2)急性期病灶中心血流灌注减少程度A与C组间差异有统计学意义(P<0.05)。结论DWI及PWI对于急性脑缺血及缺血再灌注后缺血灶的动态变化、发病机理、尤其是判定缺血半暗带的存在具有一定的价值。

Objective To study the etiology of brain is chemia injurywith DWI and PWI techniques in rats. Methods A rat model of brainischemia-reperfusion was established.45 male SD rats were randomlydivided into groups A,B and C and each group consisted of 15animals. A strand of nylon was inserted into the right middle cerebralartery to obstruct it .The brain was reperfused when the nylon strandwas removed 0.5h,1h and 2h after its insertion respectively.RoutineMRI and functional MRI were performed before and 1h,2h,3h,6h,12hand 24h after reperfusion.The findings of the 3 groups were compared.Results ①In group A,high intense signal was detected in the areadrastically shrinked with DWI in group B,different shrikage wasshown,while in group C,the area was slightly enlarged. Thedifference among the 3 groups was statistic ally significant (P<0.01).② The difference of the decrease of the blood perfusion in the centralarea of the lesion was statistically significant between groups A andC (P<0.05). Conclusion Functional MRI is an important techniqueto observe the dynamic changes of brain tissue when acute ischemiaand reperfusion occur, to study the etiology of cerebral ischemicreperfusion injury and to judge whether ischemic penumbra exists.[