Initial Experience With Ultrasound Elastography for Diagnosis of Major Salivary Gland Lesions

Objectives-The aim of this study was to evaluate the usefulness of ultrasound elastography, including conventional strain elastography, acoustic radiation force impulse (ARFI)-induced strain elastography, and point shear wave elastography (SWE) for diagnosis of major salivary gland lesions. Methods-Forty major salivary gland lesions underwent conventional sonography, conventional strain elastography, ARFI strain elastography, and point SWE before surgery or biopsy. The diagnostic performances of the sonographic and elastographic techniques were assessed with reference to histopathologic results. Results-There were 32 benign (7 Warthin tumors, 17 pleomorphic adenomas, and 8 other benign lesions) and 8 malignant (1 squamous carcinoma, 2 metastases, 2 mucoepidermoid carcinomas, 1 anaplastic carcinoma, and 2 malignant lymphomas) major salivary gland lesions on pathologic analysis. No conventional sonographic features or conventional strain elastographic scores were found to be associated with malignancy (all P>.05). The ARFI strain elastographic scores between benign and malignant lesions were statistically different (P=.032) and an ARFI strain elastographic score of 4 or greater was highly predictive of malignancy (P=.025). An ARFI strain elastographic score of greater than 3 achieved specificity of 81.3% (26 of 32) and sensitivity of 62.5% (5 of 8) in differentiating benign from malignant lesions. The shear wave velocity on point SWE did not show a significant difference in distinguishing between malignant and benign lesions (6.07 versus 4.43 m/s; P>.05). However, Warthin tumors had a trend to show lower shear wave velocities compared with pleomorphic adenomas (2.84 versus 5.27 m/s; P=.024). Conclusions-Acoustic radiation force impulse strain elastography may be potentially useful for diagnosing major salivary gland lesions, whereas conventional strain elastography and point SWE are not helpful.