Diagnostic value of shear wave elastography quantification combined with conventional ultrasound in salivary gland tumors

BACKGROUND: The histopathological classification of salivary gland tumors is extremely complex. The imaging manifestations of some tumors are nonspecific. It is particularly important to improve the value of ultrasound in the diagnosis of salivary gland tumors. This study aimed to analyze the diagnostic value of different parameters of shear wave elastography (SWE) in the quantitative diagnosis of salivary gland tumors, and to evaluate the value of SWE combined with conventional ultrasound. METHODS: The study was conducted retrospectively. Patients who underwent salivary gland tumor resection from April 2021 to November 2022 in the Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine were randomly recruited to the study. A total of 305 masses were divided into an elastography group (150 cases) and a control group (155 cases). The control group underwent conventional ultrasonography, whereas the elastography group underwent conventional ultrasonography and elastography. The Young’s modulus E of the mass was quantitatively measured in the elastography group, including maximum cross-sectional area (S), maximum Young’s modulus (Emax), mean Young’s modulus (Emean), and Young’s modulus standard deviation (SD). Pathologic diagnosis was used as the reference standard to determine the cut-off of shear wave elastography of salivary gland tumors, and the diagnostic performance of the 2 groups was compared. RESULTS: In the elastography group, the diagnostic value of Emax·S (the product of the maximum Young’s modulus of the mass and the maximum cross-sectional area of the mass) in the differential diagnosis of malignant tumors (MT) and non-malignant tumors (NMT) was the highest, with a sensitivity and specificity of 72.0% and 80.0%, respectively. The diagnostic value of Emax/D (the quotient of the maximum Young’s modulus of the mass and the maximum diameter of the mass) in the differential diagnosis of pleomorphic adenoma (PA) and adenolymphoma (AL) was the highest, with a sensitivity and specificity of 62.3% and 82.4%, respectively. The receiver operating characteristic (ROC) curves for the diagnosis of salivary gland tumors were compared between the elastography group and the control group. The area under the curve (AUC) of the elastography group was 0.915, the sensitivity, specificity, and Youden index were 84.0%, 88.0%, and 0.720, respectively. The AUC of the control group was 0.906, the sensitivity, specificity, and Youden index were 76.0%, 90.0%, and 0.660, respectively, which is the main finding of the study. CONCLUSIONS: SWE can be used as a complementary method for the diagnosis of salivary gland tumors, which has certain value in improving the diagnostic performance. As a result, the sensitivity is improved but the specificity is worsened by addition of SWE to B-mode ultrasound and color Doppler flow imaging (CDFI).