磁共振扩散加权成像高b值在诊断缺血性急性脑卒中患者中的应用

Application of high b value of magnetic resonance diffusion weighted imaging in diagnosis of acute ischemic stroke

目的探讨磁共振扩散加权成像(DWI)高b值在诊断缺血性急性脑卒中患者中的应用。方法回顾性分析2014年4月至2018年4月就诊的180例缺血性急性脑卒中患者的临床资料,均于入院5d内行DWI检查(扫描b值分别取3000s/mm^2、1000s/mm^2),比较两种b值条件下患侧、健侧ADC值,计算信噪比(SNR)与对比噪声比(CNR),并绘制患侧ADC值的受试者工作特征(ROC)曲线分析,得出曲线下面积(AUC)。结果b=3000s/mm^2时患侧、健侧ADC值均显著低于b=1000s/mm^2时ADC值,差异均有统计学意义(P<0.05);b=3000s/mm^2时SNR、CNR值虽有提高,但与b=1000s/mm^2时SNR、CNR值比较,差异无统计学意义(P>0.05);ROC曲线分析显示,b=1000s/mm^2时,AUC=0.607,诊断的准确性、敏感性及特异性分别为54.6%、61.7%、55.8%;b=3000s/mm^2时,AUC=0.856,诊断的准确性、敏感性及特异性分别为86.5%、77.1%、100%。结论DWI成像技术中选择高b值(b=3000s/mm^2)检查可显著提高缺血性急性脑卒中患者的诊断价值,较敏感地发现微小病灶。

Objective To investigate the application value of high b value of magnetic resonance diffusion weighted imaging(DWI) in diagnosis of acute ischemic stroke. Methods The clinical data of 180 patients with acute ischemic stroke who were admitted and treated in our hospital from April 2014 to April 2018 were retrospectively analyzed. All the patients underwent DWI examination within 5 d after admission to hospotial(b values of scan were 3,000 s/mm^2 and 1,000 s/mm^2 respectively). The ADC values of affected side and uninjured side under the two b values were compared between the two groups,and the ratio of signal to noise(SNR) and contrast noise ratio(CNR) were calculated,moreover the receiver operating characteristic(ROC) curve analysis of affected side ADC values was performed to obtain the area under curve(AUC). Results The ADC values of affected side and uninjured side(b = 3,000 s/mm^2) were significantly lower than those at the time of b = 1,000 s/mm^2(P < 0. 05). Although the value of SNR and CNR were improved when b = 3,000 s/mm^2,however there were no significant differences in the values of SNR and CNR,as compared with those when b = 1,000 s/mm^2(P> 0. 05). ROC curve analysis showed that when b = 1,000 s/mm^2 and AUC was 0. 607,the accuracy,sensitivity and specificity of diagnosis were 54. 6%,61. 7% and 55. 8%,respectively. Moreover when b = 3,000 s/mm^2 and AUC was0. 856,the accuracy,sensitivity and specificity of diagnosis were 86. 5%,77. 1% and 100%,respectively. Conclusion The selection of high b value(b = 3,000 s/mm^2) in DWI imaging technique can significantly improve the diagnostic value for the patients with acute ischemic stroke,which can more sensitively detect the tiny lesion.