脑梗死后微血管渗透性改变及出血性转化的预测

目的探讨缺血性脑梗死后急性期和亚急性期微血管渗透性改变及脑梗死后出血性转化(hemorrhagic transformation,HT)的预测。材料与方法收集缺血性脑梗死病人43例,急性期10例,亚急性期33例,进行常规MRI及DCE-MRI扫描。利用药代动力学模型计算容积转运常数Ktrans,比较每一个病人梗死区和对侧正常脑组织的Ktrans值以及出血组和非出血组的Ktrans值有无差异,比较不同时期梗死区强化对预测HT的意义。结果所有病人梗死区Ktrans值较对侧正常脑组织明显增高(P0.05)。10例在急性期有脑实质强化的病人都有继发出血,在亚急性期和慢性期15例病人有继发出血,18例没有继发出血,Fisher's精确检验有统计学意义(P0.05)。与亚急性期HT或没有HT的病人相比,急性期有HT组病人的Ktrans值明显增高(P0.05),但是亚急性期HT和非HT的病人Ktrans值比较没有统计学差异(P0.05)。结论急性期脑实质强化对HT的预测有更高的特异性,且渗透性比亚急性期更高。早期脑实质强化及HT与毛细血管内皮的紧密连接和基底膜损伤有关。后期脑实质强化及HT与侧枝循环的建立有关,DCE-MRI可以定量评估血脑屏障的渗透性,对进一步研究HT的分型提供更科学的依据。

Microvascular permeability changes in ischemic stroke and prediction of hemorrhagic transformation

AbstractObjective:To evaluate the permeability changes in ischemic infarction in patients of acute stage and subacute stage and to predict the post-infarction hemorrhagic transformation.Materials and Methods:The data of 43 patients (10 acute stage and 33 subacute stage) who had routine MRI and DCE-MRI performed were retrospectively analyzed. Volume transitional co-efifciency (Ktrans) was measured with pharmacokinetic model. Statistical analysis of Ktrans was performed in the following different groups: infarcted tissue and contralateral normal tissue; hemorrhagic group and non- hemorrhagic group. The correlation of enhancement of different stages was analyzed byFisher's test.Results:The Ktrans values of infarcted areas dramatically increased compared to those in the conterlateral’s in all cases (P<0.05). Subsequent hemorrhage was found in all 10 cases of acute stage and 15 cases of subacute stage while not found in the rest 18 cases, which was statistically different withFisher's test (P<0.05). Ktrans values of cases with HT of acute stage were significantly higher than those with or without HT in subacute stage respectively (P<0.05). However, there was no statistical difference in Ktrans values between HT group and non-HT group in subacute stage. Conclusion:The speciifcity was better in early parenchymal enhancement in predicting HT and the permeability was higher compared to later periods. Early parenchymal enhancement and subsequent HT is likely associated with injury of early capillary endothelial cells of tight dense connections and basement membranes. Parenchymal enhancement in later period and HT is likely associated with establishment of collateral circulation. DCE-MRI could quantitatively evaluate osmotic quantity. It is of great help for further research on HT category.