联合磁共振弥散加权成像和三维伪连续动脉自旋标记对急性缺血性脑卒中的研究

摘要

目的 联合应用磁共振弥散加权成像(DWI)和三维伪连续动脉自旋标记(3D-PCASL)对急性缺血性脑卒中(AIS)进行研究.方法 纳入45例发病48h内临床疑似AIS患者.所有患者接受磁共振常规序列、血管成像(MRA)、DWI和3D-PCASL检查.根据MRA和DWI表现,上述患者确诊为AIS病例.在患侧DWI高信号区和对侧镜像脑区勾画感兴趣区(ROI),测量表观扩散系数(ADC),并在同一层面勾画同样大小感兴趣区,测量脑血流量(CBF).采用配对t检验,观察患侧区与镜像区ADC、CBF值的差异;pearson相关性检验,分析ADC和CBF值的相关性;回归分析结合受试者工作特征(ROC)曲线,用以比较不同参数及参数组合对AIS诊断的效能.结果 患侧DWI信号增高,ADC值较对侧下降:0.50±0.15 VS.0.80 ±0.13um2/ms,P＜0.001;患侧区ASL灌注减低,CBF较对侧下降:17.04±6.97 VS.(34.14±13.53)ml· 100g-1·min-1,P ＜0.001.ADC及CBF呈统计学正相关,(r=0.583,P＜0.001).回归分析及ROC曲线显示,联合ADC及CBF值对AIS诊断效能最高(特异性=93.3％,敏感性=86.7％,曲线下面积=0.955).结论 供血中断会导致细胞代谢紊乱,表现ADC值降低,联合DWI和3D-PCASL成像有利于AIS的临床诊断.%Objective The aim of this study is to assess the combination of diffusion weighted imaging (DWI) and three-dimensional pseudo-continuous arterial spin labeling (3D-PCASL) in patients with acute ischemic stroke (AIS).Methods Patients with suspected AIS were examined by magnetic resonance imaging within 48 h of symptom onset.Forty-five patients (mean age was 66.27 ± 13.27 years) who underwent magnetic resonance angiography (MRA) and DWI was identified as having AIS with ischemic core was enrolled,where ischemic core referred to the area of high DWI signal and decreased apparent diffusion coefficient (ADC) value.ADC and ASL cerebral blood flow (CBF) were measured.The paired t-test was applied to compare ASLCBF and DWI-ADC measurements between ischemic core and contralateral normal brain regions.Pearson's correlation was used to evaluate the correlations among quantitative results.Linear regression and receiver operating characteristic (ROC) curve were applied to assess the difference of diagnostic efficacy anong different quantitative parameters.Results The ADC and CBF values of ischemic penumbras were significantly lower than those of the contralateral norinal brain regions (0.50 ± 0.15 VS.0.80 ± 0.13 um2/ms,P ＜ 0.001;17.04 ± 6.97 VS.34.14 ± 13.53 ml · 100 g-1 · min-1,P ＜ 0.001,respectively).A significant correlation was detected between ADC and CBF (r =0.583,P ＜0.001).The combination of ADC and CBF performed best in diagnosis of AIS with the area of under ROC curve (AUC) 0.955.Conclusion The decrease in cerebral blood perfusion primarily results in the decrease ADC in ischemic core.The combination of DWI and 3D-PCASL has important clinical significance for diagnosis of AIS.