The Application Study Of Ultrasonic Elastography Strain Ratio In The Differential Diagnosis Of Benign And Malignant Salivary Gland Nodules

OBJECTIVE:To discuss the application value of the method of real-time ultrasonic elastography strain ratio(SR)in the diagnosis of salivary gland nodules through making use of the differences in hardness caused by the difference in the internal structure of biological tissue and to determine the best diagnostic demarcation point of SR value for the diagnosis of benign and malignant salivary gland nodules.METHODS:100 patients with unilateral salivary gland nodule who were received and treated by our hospital from January 2018 to February 2019 were selected to receive a routine ultrasonic examination,and the routine date were completely recorded.Then the ultrasonic elastography examination was performed to measure the strain index of the normal salivary gland(E1)and the elastic strain index of the tumor(E2)through the method of ultrasonic elastography strain ratio.SR(SR= E2/E1)which was the average of three different nodule biopsies.All patients should undergo the operation and the queries of histopathological results were available.According to the histopathological results,the lesions were divided into benign group and malignant group.And the differences of the elastography SR of benign and malignant nodules were evaluated.RESULTS:Among the 100 cases of salivary gland nodules,70 cases were benign(including 39 cases of pleomorphic adenoma,25 cases of Warthin’s tumors,2 cases of inflammatory mass,2 cases of myoepithelioma and 2 cases of hemangioma).Other30 cases were malignant nodule(including 21 cases of mucoepidermoid carcinoma,3cases of squamous cell carcinoma,2 cases of acinic cell carcinoma,3 cases of adenoid cystadenocarcinoma and 1 case of malignant mixed tumor).The nodules of95 cases were located in the parotid gland and that of the other 5 cases were located in the submandibular gland.83 cases were correctly diagnosed by conventional ultrasound,including 62 cases of benign nodules and 21 cases of malignant nodules.Ultrasonic elastography SR correctly diagnosed 93 cases,including 67 cases of benign nodules and 26 cases of malignant nodules.The SR of the benign nodules was(2.64±0.61)and that of malignant nodules was(4.40±1.06),P<0.05,and the comparison of the two circumstances had statistical significant.Constructs the ROC curve,and the area under the ROC curve was 0.90 and the youden index was 0.796.And the best diagnostic demarcation point of SR for identifying benign and malignant nodules was 3.30.When SR≥3.30,the nodule was malignant.When SR<3.30,the nodule was benign,and the sensitivity,specificity and accuracy in the diagnosis of benign and malignant salivary gland nodules were respectively 86.7%,92.2%,and90.4%.CONCLUSION:The application of real-time ultrasound elastography strain ratio(SR)in the diagnosis of benign and malignant salivary gland nodules has statistical difference.The real-time Ultrasound elastography strain ratio can improve the accuracy of non-invasive diagnosis of salivary gland nodules,and provide the important theoretical basis for the clear clinical diagnosis of benign and malignant salivary gland nodules,having high clinical value.