Objective: To investigate the clinical value of magnetic resonance (MR) intravoxel incoherent motion (IVIM) diffusion imaging and 3D pseudo continuous arterial spin labeling (3D-pcASL) perfusion imaging in the evaluation of acute cerebral infarction. Methods: MR images of 49 patients with unilateral acute cerebral infarction diagnosed and treated in Affiliated Yancheng Hospital of Southeast University Medical College from October 2015 to February 2019 were retrospectively analyzed. High signal infarction area (S(D)) on diffusion image slice with the biggest lesion level and abnormal perfusion area (S(CBF)) on the corresponding level were measured. The presence of ischemic penumbra (IP) was represented by S(CBF)> S(D), and patients were divided into group IP and group non-IP. Regions of interest were set on the infarction core, brain tissue near the edge of the lesion (BNL) and their corresponding contralateral regions. The values of apparent diffusion coefficient (ADC), true diffusion coefficient (D), perfusion related diffusion coefficient (D(*)), perfusion fraction (f) and cerebral blood flow (CBF) of each region of interest were recorded and relative values of infarction lesion to its contralateral region (rADC, rD, rD(*), rf, rCBF) were calculated. Differences of each parameter value between infarction core, BNL and their corresponding contralateral regions and of each relative parameter value between infarction core and BNL, and between the two groups were compared.The differential diagnostic efficacy of relative parameter value with differences between groups was analyzed by receiver operating characteristics (ROC) curve. The correlations of each relative parameter value of 3D-pcASL and IVIM sequences were analyzed. Results: The ADC, D, f and CBF values of infarction core were significantly lower than those of contralateral regions in both groups (all P<0.01). Among all parameters of BNL in both groups, only the CBF value of group IP was significantly lower than that of contralateral region ((27.58±3.53) vs (41.20±5.66) ml·100 g(-1)·min(-1), P<0.01). The rADC, rD, rf and rCBF of infarction core were significantly lower than those of BNL in both groups (all P<0.01). The rCBF of BNL in group IP was significantly lower than that in group non-IP (0.68±0.12 vs 0.97±0.15, P<0.01), and the area under the curve was 0.949, the optimal threshold was 0.823, and the youden index was 0.855 for identifying the two groups. Other relative parameters values of infarction core and BNL had no statistical difference between the two groups. There were positive correlations between rCBF and rADC, rD, rf (r=0.428,0.335,0.565) of infarction core, rADC and rD, rf (r=0.853,0.602) of infarction core, also rADC and rD (r=0.336) of BNL (all P<0.05). Conclusions: IVIM can effectively evaluate the difusion and perfusion information of acute cerebral infarction lesions. However, its perfusion related parameters are not as good as 3D-pcASL in IP evaluation, which should be flexibly selected according to the actual needs of patients' condition evaluation.
目的： 探讨磁共振（MR）体素内不相干运动（IVIM）扩散成像和三维伪连续动脉自旋标记（3D-pcASL）灌注成像在急性脑梗死评估中的临床应用价值。 方法： 对东南大学医学院附属盐城医院2015年10月至2019年2月期间诊治的49例单侧急性脑梗死患者的MR图像进行回顾分析。测量扩散图像病灶最大层面高信号梗死面积（S(D)）以及相应层面异常灌注面积（S(CBF)）。以S(CBF)>S(D)表示存在缺血半暗带（IP），将患者分为IP组和无IP组。选取患者梗死核心、近病灶边缘脑组织（BNL）及相应对侧为感兴趣区。记录各感兴趣区的表观扩散系数（ADC）、真实扩散系数（D）、灌注相关扩散系数（D(*)）、灌注分数（f）和脑血流量（CBF）参数值并计算梗死侧/对侧相对值（rADC、rD、rD(*)、rf、rCBF）。比较梗死核心、BNL的各参数值与对侧差异，各参数相对值在梗死核心和BNL间以及两组间的差异。采用受试者工作特征（ROC）曲线分析存在组间差异的参数相对值在两组间的鉴别诊断效能。并分析3D-pcASL与IVIM序列各相对参数值之间的相关性。 结果： 两组梗死核心的ADC、D、f和CBF值均明显低于对侧（均P<0.01）。两组BNL各参数值中仅IP组CBF值明显低于对侧[（27.58±3.53）比（41.20±5.66）ml·100 g(-1)·min(-1)，P<0.01]。两组梗死核心的rADC、rD、rf和rCBF均明显低于BNL（均P<0.01）。IP组BNL的rCBF明显低于非IP组（0.68±0.12比0.97±0.15，P<0.01），其鉴别两组的曲线下面积为0.949，最佳阈值为0.823，约登指数为0.855。其余两组梗死核心和BNL的各参数相对值组间差异均无统计学意义。梗死核心的rCBF与rADC、rD、rf（r=0.428、0.335、0.565），rADC与rD、rf（r=0.853、0.602）以及BNL的rADC与rD（r=0.336）均呈正相关（均P<0.05）。 结论： IVIM可有效评估急性脑梗死病灶扩散和灌注信息，然而其灌注相关参数对IP的评估能力不如3D-pcASL，临床需结合患者病情评估实际需要而灵活选用。.
Keywords: Brain ischemia; Cerebral infarction; Diffusion magnetic resonance imaging; Perfusion imaging.