The Role of Real-Time Sonoelastography in the Differentiation of Benign From Malignant Parotid Gland Tumors.

OBJECTIVE: The aims of this study are to evaluate the utility of sonoelastography for parotid gland masses and to determine which cutoff strain ratio (SR) would be best for the differentiation between benign and malignant lesions. METHODS: From August 2015 to December 2016, 39 parotid gland masses were examined prospectively by ultrasonography and strain sonoelastography. Elastographic scores were determined by a 4-point scoring method. Interventional procedures were performed on all patients after sonographic examinations. The lesions were divided into groups as benign or malignant according to histopathological findings. The difference in elastographic scores between benign and malignant masses was evaluated. RESULTS: Among the 39 parotid gland masses, 33 (84.6%) were benign and 6 (15.3%) were malignant tumors with 53.8% (n = 21) of the lesions being on the right side. Pleomorphic adenoma (41%) was the most common neoplasm followed by Warthin tumor (28.2%). The median elastographic score was 2 (range, 1-3) for benign tumors, and it was 3 (range, 2-4) (P = 0.003) for malignant tumors. Median SR was 1.11 (range, 0.26-2.15), and it was 2.75 (range, 1.03-3.54) (P = 0.01) for benign and malignant tumors. In the receiver operating characteristic analysis, the cutoff value of the SR was 2.1, sensitivity was 83.3%, specificity was 97%, positive predictive value was 83.3%, negative predictive value was 97%, and accuracy was 94%. CONCLUSIONS: There was a statistically significant difference between benign lesions and malignant lesions in both elastography score and SR. It is possible that elastography can improve the noninvasive diagnostic accuracy for certain pathological conditions.