基于IVIM对急性缺血性脑卒中血管再通治疗后出血转化的预测

摘要

目的 探讨体素内不相干运动(introvoxel incoherent motion, IVIM)成像对预测急性缺血性脑卒中(acute ischemic stroke, AIS)血管再通治疗后出血转化(hemorrhagictransformation, HT)的意义,为临床个体化治疗提供依据.材料与方法 收集经临床/影像确诊的AIS患者60例,在血管再通治疗前行磁共振多b值扩散加权成像(diffusionweightedimaging, DWI)扫描,应用IVIM成像技术重建患侧梗死区及对侧镜像区的慢速表观扩散系数(diffusion coefficient of pure diffusion, D)、快速表观扩散系数(pseudo-diffusion coefficient、D*)、灌注分数(perfusion fraction, f)值,计算各参数的相对值(r D、rD*、rf);在治疗后3 d内行磁共振磁敏感加权成像(susceptibility weighted imaging, SWI)扫描,观察患者HT发生的情况;分析AIS患者治疗前IVIM参数与治疗后HT的关系.结果 AIS患者血管再通治疗前患侧梗死区的D、D*、f值均低于对侧镜像区,双侧比较差异有统计学意义(t=12.934、12.234、24.069,P＜0.01);HT组患者治疗前梗死区的rD、rD*、rf均值低于非HT组,两者比较差异有统计学意义(t=2.982、3.090、4.656,P＜0.01);应用受试者工作特性曲线分析HT组与非HT组rD、rD*、rf值的曲线下面积分别为0.798、0.822、0.883;rD最佳阈值为0.527,敏感度为76.9％,特异性为73.7％;rD*最佳阈值为0.519,敏感度为84.6％,特异性为78.9％;rf最佳阈值为0.495,敏感度为84.6％,特异性为89.5％.结论 AIS患者血管再通治疗后有HT的风险,治疗前梗死区的IVIM参数可以预测治疗后发生HT的风险,以rf值的预测效能最高.%Objective: To explore the significance of introvoxel incoherent motion (IVIM) imaging in predicting the hemorrhagic transformation (HT) of acute ischemic stroke (AIS) after revascularization and provide theoretical basis for individualized therapy. Materials and Methods: 60 patients with AIS confirmed by clinical or imaging examination were studied and all the patients were scanned with multi-b diffusion-weighted imaging (muti-b DWI) before revascularization. We used IVIM imaging technique to measure the three coefficients inclouding diffusion coefficient of pure diffusion (D), pseudo-diffusion coefficient (D*) and perfusion fraction (f) in infarct value and mirror region and then we calculated the relative values of each parameter (rD, rD*, rf). Further, we performed susceptibility weighted imaging (SWI) within3 days after treatment, to observe the hemorrhagic transformation and analyze the relationship between IVIM parameters and HT after treatment in patients with AIS. Results: The D, D*, f values of the infarct area on the affected side of AIS patients before revascularization were lower than those of the contralateral mirror area, even there was a significant difference between the two sides (t=12.934, 12.234, 24.069, P＜0.01). the rD, rD*, rf values of the infarct area in the HT group before treatment were lower than those in the non-HT group, and there was a significant difference between the two groups (t=2.982, 3.090, 4.656, P＜0.01). After taking the optimal threshold of rD 0.527, rD* 0.519 and rf 0.495, the sensitivity and the specificity were 76.9％, 73.7％;84.6％, 78.9％;84.6％, 89.5％ respectively. Conclusions: IVIM parameters of infarct area before treatment can predict a risk of HT in patients with AIS after revascularization, even having the highest value of rf.