亚急性期脑梗死的体素内不相干运动扩散加权成像

目的 探讨体素内不相干运动（IVIM）成像评价亚急性期脑梗死弥散和灌注情况的价值。方法 回顾性分析35例亚急性期脑梗死患者的MR影像资料，包括常规DWI、IVIM成像及三维动脉自旋标记（3D-ASL）序列检查。通过常规DWI序列获得ADC图，IVIM序列获得纯水分子扩散系数（D）图、灌注相关扩散系数（D^*）图、灌注分数（f）图，3D-ASL序列获得脑血流量（CBF）图。分别测量脑梗死灶及对照侧镜像区ADC值、D值、D^*值、f值、CBF值及其相对值（rADC、rD、rD^*、rf、rCBF）。比较脑梗死灶与对照侧镜像区各参数的差异，并分析rADC值与rD、rD^*、rf值的相关性及rCBF值与rD、rD^*、rf值的相关性。结果 脑梗死灶ADC、D、D^*、f、CBF值均较对照侧镜像区减低（P均<0.05）。rADC值与rD、rf值呈正相关（r=0.687、0.601，P=0.005、0.018）；rCBF值与rf值呈正相关（r=0.581，P=0.022）。结论 IVIM成像能同时提供亚急性期脑梗死的灌注及弥散信息，有助于进一步阐明亚急性期脑梗塞的机制。

Intravoxel incoherent motion imaging in subacute brain infarction

Objective To explore the value of intravoxel incoherent motion (IVIM) imaging in evaluating diffusion and perfusion variations in subacute brain infarction.Methods MRI data of 35 patients with subacute brain infarction were analyzed retrospectively,including routine DWI,IVIM imaging and three-dimensional arterial spin labeling (3D-ASL) sequence.The ADC maps were obtained by routine DWI sequence.Pure molecular-based diffusion coefficient (D) maps,pseudo diffusion coefficient of perfusion (D^*) maps and perfusion fraction (f) maps were obtained by IVIM sequence.Cerebral blood flow (CBF) maps were obtained by 3D-ASL sequence.ADC,D,D^*,f,CBF values and the relative values (rADC,rD,rD^*,rf,rCBF) of brain infarction lesion and contralateral mirror area were calculated.All the parameters between brain infarction lesion and contralateral mirror area were compared.The correlations were analyzed between rADC value and rD,rD^*,rf values respectively,as well as between rCBF value and rD,rD^*,rf values respectively.Results Quantitative analysis showed significant decreases of ADC,D,D^*,f and CBF values in the brain infarction lesion compared with those in the contralateral mirror area (all P<0.05).There were positive correlations between rADC value and rD,rf values (r=0.687,0.601,P=0.005,0.018).And the positive correlation was found between rCBF value and rf value (r=0.581,P=0.022).Conclusion IVIM imaging can concurrently provide the perfusion and diffusion informations of subacute brain infarction patients,which is helpful to further elucidate the mechanisms of subacute brain infarction.