The Effect Of Conventional Ultrasound And Shear Wave Elastography On The Diagnosis Of Benign And Malignant Cervical Lymph Nodes

Objective:（1）To investigate the effect of different indexes on the diagnosis of benign and malignant cervical lymph nodes by conventional ultrasonography.（2）To investigate the effects of different regions of interest（ROI）and elastic modulus values on cervical benign and malignant lymph nodes in shear wave elastography（SWE）and to evaluate their diagnostic value.Methods:From June 2017 to June 2018,102 patients with 138 cervical enlarged lymph nodes confirmed by puncture biopsy or surgical pathology in the Affiliated Hospital of Qingdao University were selected.Routine ultrasonography was performed before operation.The zoning,size,aspect ratio,single or multiple,boundary and internal echoes of enlarged lymph nodes,fusion,lymphatic hilum,calcification and internal blood flow typing,and the relationship between lymph node area,depth and neighboring tissues（such as sternocleidomastoid muscle and cervical vessels）were recorded in detail.The above indexes affecting cervical lymph nodes were compared and analyzed.Then SWE was checked and three different ROIs were set up:ROI-S is a small circular ROI with a diameter of 2 mm,placed in the most hard region of the lymph node;ROI-B is the largest tangential ROI that does not exceed the edge of lymph node,which contains the hardest area of lymph nodes;ROI-T is the manual outline of the entire lymph node edge ROI.4 parameters of 3 ROIs,that is,the maximum modulus of elasticity(E_max),the mean elastic modulus value(E_mean),the minimum modulus of elasticity(E_min)and the elastic standard deviation（SD）were measured and analyzed.The receiver operating characteristic curve（ROC）was constructed and the area under curve（AUC）was calculated.The sensitivity,specificity and Joden index were compared and their diagnostic efficacy were analyzed.Results:（1）The different indicators of 138 lymph nodes were compared and analyzed by routine ultrasonography.It was found that there were significant differences between benign and malignant cervical lymph nodes in transverse diameter,location,aspect ratio,shape,calcification,lymphatic hilum and blood flow type,respectively（t orχ²=4.677,10.569,5.821,9.447,64.709,7.078 and 33.917,all P<0.05）.There was no significant difference in age,length,diameter,area and depth,respectively（t orχ²=-1.145,-1.731,-1.879 and-0.940,all P>0.05）.（2）SWE results:The elastic modulus values of benign and malignant lymph nodes in 3 ROIs were higher than those of benign lymph nodes except E_min measured by ROI-T（all P<0.05）.There was no significant difference in E_max between benign,malignant and total lymph nodes measured by 3 ROIs（all P>0.05）,but the overall differences of E_mean,E_min and SD were statistically significant（all P<0.001）.The results of ROC curve analysis showed that there was no significant difference in AUC between benign and malignant lymph nodes detected by E_max measured by 3 kinds of ROIs（all P>0.05）.The AUC of E_meanean measured by ROI-S was higher than that of ROI-B and ROI-T（both P<0.05）,and the AUC of SD was lower than that of ROI-B and ROI-T（both P<0.05）,but there was no significant difference between them（both P>0.05）.The AUC of E_min measured by ROI-B and ROI-T was less than 0.700 and the diagnostic efficiency was low.Conclusion:（1）Conventional ultrasound can differentiate benign and malignant cervical lymph nodes by transverse diameter,location,shape,aspect ratio,calcification,lymphatic hilum and blood flow classification.（2）SWE can directly and automatically measure the modulus of elasticity of cervical lymph nodes,and can differentiate benign and malignant cervical lymph nodes.（3）The diagnostic efficiency of SWE varies with the selection of ROI and modulus of elasticity.No single modulus of elasticity has superior diagnostic efficiency.When choosing a smaller ROI,it is recommended to use E_max and E_mean,When choosing a larger ROI,E_max and SD are recommended.（4）E_max has no dependence on ROI.When E_max is selected,the sensitivity is the highest,the Yoden index is the best and the diagnostic efficiency is the best.Therefore,E_max is recommended as the best choice.