磁共振DWI对肝脏局灶性良恶性病变诊断准确性研究

Research on the Diagnostic Accuracy of Magnetic Resonance DWI in Differentiating Hepatic Focal Benign and Malignant Lesions

目的:分析磁共振(MR)弥散加权成像(DWI)序列的表观弥散系数(ADC)值在鉴别肝脏局灶性良恶性病变中的诊断价值。方法:回顾分析在我院接受检查的49例肝脏局灶性病变患者的MRI图像。将MR平扫+DWI图像阅片诊断良恶性结论与确诊结果进行对比,分析诊断的准确率、灵敏度、特异度、阳性预测值(PPV)和阴性预测值(NPV)。测量病灶表观弥散系数(ADC)值,根据确诊结果分为良性组和恶性组,比较两组ADC值差异。采用ROC曲线分析阅片诊断、ADC值在两组间的鉴别诊断效能。结果:阅片诊断肝脏良恶性病变的准确率为75.51%,敏感性为86.96%,特异性为65.38%,PPV为68.97%,NPV为85.00%,曲线下面积为0.770,约登指数为0.540。恶性组病灶ADC值为明显低于良性组(P<0.001)。ADC值鉴别良恶性病灶的最佳阈值为1.345×10^-3mm^2/s,曲线下面积为0.872,对应的敏感性为96.2%,特异性为60.9%,约登指数为0.570。结论:DWI序列的定量参数ADC值具有比常规阅片更高的鉴别肝脏良恶性病变的诊断效能,值得临床工作中推广应用。

Objective:To analyze the diagnostic value of apparent diffusion coefficient(ADC) value of magnetic resonance(MR) diffusion weighted imaging(DWI) sequence in differentiating hepatic focal benign and malignant lesions.Methods:MRI images of 49 patients with hepatic focal lesions were retrospectively analyzed in our hospital. The benign and malignant conclusions of MRI plain scan + DWI image were compared with the confirmed results, and the diagnostic accuracy, sensitivity, specificity, positive predictive value(PPV) and negative predictive value(NPV) were analyzed. The apparent dispersion coefficient(ADC) of the lesion was measured and compared between benign group and malignant group according to the confirmed results. ROC curve was used to analyze the differential diagnosis efficiency of ADC value between the two groups.Results:The diagnostic accuracy, sensitivity, specificity, PPV, NPV, area under the curve and Youden index of images reading were 75.51%, 86.96%, 65.38%, 68.97%, 85.00%, 0.770 and 0.540, respectively. The ADC value of the malignant group was significantly lower than that of the benign group(P<0.001). The optimal threshold for ADC value to identify benign and malignant lesions was 1.345×10^-3mm^2/s, the area under the curve was 0.872, the corresponding sensitivity was 96.2%, the specificity was 60.9%, and the Youden index was 0.570.Conclusion:The quantitative parameter ADC value of DWI sequence has a higher diagnostic efficiency of differentiating benign and malignant hepatic lesions than that of conventional images reading, which is worthy of promotion and application in clinical work.