基于多模态磁共振技术的急性缺血性脑卒中出血转化风险的预测研究

Hemorrhagic transformation (HT) is a severe complication in patients with acute ischemic stroke (AIS) after thrombolytic and/or mechanical thrombectomy therapy. Parenchymal hematoma (PH) is a more severe form of HT and is independently associated with an increased risk for death or disability. In our recent study, we demonstrated a strong association between post-ischemic hyperperfusion and HT in AIS patients. However, post-ischemic hyperperfusion alone is not sufficient to elucidate the pathogenesis of HT, especially PH. In some patients, hyperperfusion may even lead to DWI lesion reversal. Based on this, we hypothesize that:①the role of hyperperfusion (detrimental or protective) depends not only on its own degree but also on the level of baseline ischemia and collateral circulation; ②post-treatment hyperperfusion with severe baseline ischemia and lack of collateral circulation is more likely to cause HT; concurrent increased BBB permeability within hyperperfusion area can help to predict HT more precisely. This proposal will evaluate AIS patients pre- and post-treatment based on multimodal magnetic resonance imaging to distinguish hyperperfusion with detrimental or protective effect. We will investigate the mechanism of HT occurrence based on associated factors such as severe ischemia, poor collateral, hyperperfusion injury and BBB disruption. Combined with patient clinical features, we expect the established mathematical model with multi-parameter can predict the occurrence of HT (especially PH) accurately which may guide clinical treatment strategy in future.

出血转化（HT）是急性缺血性脑卒中（AIS）患者溶栓或介入取栓后严重的并发症，其亚型脑实质出血（PH）可导致重度残疾或死亡。我们的研究表明脑缺血后高灌注状态与HT密切相关。但是单一的脑高灌注模型不足以阐明HT，特别是PH的发生机制；在部分患者，脑高灌注甚至会保护脑梗死核心灶使其发生逆转恢复（DWI lesion reversal）。基于此，我们认为：①高灌注起到损伤还是保护作用取决于基线时缺血程度、侧支循环强弱以及治疗后高灌注程度；②缺血严重、侧支循环缺乏者，脑高灌注易导致HT；伴随血脑屏障（BBB）通透程度增高可更加准确的预测HT。本项目将基于多模态磁共振检查，对AIS患者治疗前后进行评估，区分高灌注损伤、高灌注保护两种迥异作用效果的影像学基础；研究缺血-侧支循环不良-高灌注损伤-BBB通透度改变-出血转化的影像学机制，结合患者临床特征，建立多参数数学模型以期准确的预测HT及PH的发生。

背景与目的：本研究旨在量化严重缺血脑组织再灌注水平，并评估其与严重颅内出血转化（HT）的关系。.方法：对102例患者在溶栓或介入取栓后24小时内进行ASL和DWI检查。取ADC<550×10-6mm2/s识别梗死核心灶，获取梗塞核心灶内及其健侧镜像区域的CBF值。记录对侧镜像区域第25，50和第75个百分位的CBF值，并分别将其定义为病变侧再灌注状态的阈值。根据心肌梗塞溶栓（TIMI）标准确定血管再通，二分法分为血管再通（TIMI 2-3）或未开通（TIMI 0-1）。.结果：56/102（55%）患者发生HT，包括27/102例（26%）HI、16/102例（16%）PH1和13/102例（13%）PH2。在预测PH值（0.782 vs.0.685，P=0.002）和PH-2（0.844 vs.0.749，P=0.0027）时，ASL再灌注vol-25的AUC显著高于ADC阈值。对于二元PH值与无PH值的预测，单变量分析显示只有ASL再灌注vol-25（P<0.001）是一个显著的预测因子。逐步多元logistic回归分析中，只有ASL再灌注vol-25（OR=3.62，95%CI 1.71-7.64，P<0.001）是PH的显著预测因子。.结论：脑卒中后严重缺血脑组织的再灌注水平与严重出血转化密切相关。

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