RESUMO
Objective To investigate the diagnostic value of elasticity contrast index(ECI)in the differential diagnosis between benign and malignant cervical lymph nodes.Methods Cervical lymph nodes of 48 patients were examined by traditional ultrasound and ECI in Peking University Third Hospital between December 2016 and April 2017. Patients were further divided into free-hand group and non-free-hand group according to the use of manual compression or not. With pathological or clinical follow-up results as the gold standard,we compared the diagnostic values of traditional ultrasound,ECI,and their combination in the differential diagnosis between benign and malignant lymph nodes.Results Totally 138 lymph nodes were collected from 46 patients,among which 76 were benign and 62 were malignant. The ECI value of malignant lymph nodes(1.69±0.89)were significantly higher than that of benign lymph nodes(1.32±0.87)(t=-2.46,P=0.015).The area under receiver operating characteristic(ROC)curve for traditional ultrasound in discrimination of malignant cervical lymph nodes with benign ones was 0.899,with an optimal cut-off value of 7,which had a sensitivity of 93.5% and a specificity of 84.2%. The area under ROC curve for ECI was 0.649,with an optimal cut-off value of 1.25,which had a sensitivity of 59.7% and a specificity of 60.5%. For their combination,the area under ROC curve was 0.724,with a sensitivity of 93.5% and a specificity of 51.3%. In the group without using free-hand technique,the mean ECI value was 1.77±0.94 for malignant nodes,which was significantly higher than that(1.26±0.81)for benign nodes(t=-3.09,P=0.003). In the group requiring free-hand technique,the ECI value for malignant nodes was 1.33(1.01,1.44),showing no significant difference with benign ones[1.32(0.78,2.18);z=-0.20,P=0.843].Conclusions Conventional ultrasound has higher diagnostic value than ECI and their combination in differentiating benign and malignant lymph nodes. The role of ECI in evaluating other organs requires further investigations.