Early results of real-time qualitative sonoelastography in the evaluation of parotid gland masses: a study with histopathological correlation.

BACKGROUND: Sonoelastography has been used to differentiate malignant from benign lesions in numerous types of tissues including breast, prostate, liver, blood vessels, thyroid, musculoskeletal structures, and salivary glands.
PURPOSE: To evaluate the efficacy and application of real-time qualitative sonoelastography in the differentiation of benign and malignant focal parotid gland lesions.
MATERIAL AND METHODS: A total of 75 patients (36 boys/men, 39 girls/women; age range, 10-83 years) with 81 lesions were evaluated prospectively by sonoelastography performed and interpreted by two expert radiologists. The results of these experts classification and scoring of lesions according to relative stiffness of the mass were compared with each other and with histopathological findings. The interpretation of sonoelastography scores of 1-4 were as follows: 1, soft; 2, mostly soft; 3, mostly stiff; and 4, stiff.
RESULTS: The kappa statistic of 0.508 (P < 0.001) indicated moderate agreement between the two radiologists. The sonoelastography scores correctly diagnosed 30 of 49 benign tumors (sensitivity, 61.2%) and 19 of 32 malignant tumors (specificity, 59.4%). The area under the receiver-operating characteristic curve was 0.603. The diagnostic value of sonoelastography for evaluating pleomorphic adenomas, Warthin tumors, adenoid cystic carcinoma, and high-grade tumors was low, whereas the diagnostic rates for low-grade tumors such as mucoepidermoid carcinoma, acinic cell carcinoma, and metastases of basal cell carcinoma were better with sonoelastography.
CONCLUSION: Although sonoelastography seems to be promising in the differentiating of low-grade malignancies, the primary role of radiology is currently limited to determination of localization, size, and morphology of parotid tumors.