Sonoelastographic Features of Major Salivary Gland Tumors and Pathology Correlation

To investigate the diagnostic efficiency of elastography in differentiation of malignant and benign tumors by evaluating salivary gland masses in means of their elastography scores and strain ratios.
Patients and Twenty five patients with salivary gland mass lesions were detected through B- mode ultrasonography, Doppler ultrasonography, strain elastography and their strain ratios were calculated. The results were compared with histopathologic results.
Twenty five patients had 27 lesions consisting of seven malignant and 20 benign lesions. Mann Whitney U test, ROC analysis, Fisher test and Chi square tests were used statistically. Mean strain rates were calculated as 2.26 ± 0.29 in the benign group and 2.02 ± 0.59 in the malignant group. There was no statistically significant difference between the two groups (P = 0.698). Elastography score was calculated as mean 2.4 ± 0.94 in the benign group and mean 2.28 ± 0.38 in the malignant group. There was no statistically significant difference between the two groups (P = 0.708). Accepting the strain rate as 0.89; sensitivity of elastography in differentiating malignant from benign lesions is 71%, and the specificity is 50%. However, the area under the ROC curve is 0.55, which is not statistically significant (P = 0.699).
In conclusion, elastography is a supporting method for B-mode ultrasonography in the differentiation of benign and malignant salivary gland masses. However, the overlap of elastographic findings is evident in benign and malignant masses. Care should be taken to have tissues with similar stiffness under the reference tissue and the lesions in elastographic evaluation of the superficial mass. We have not met a study that has pointed out the importance of stiffness of the tissue located beneath the lesion that may affect the elastography results in the literature. In this respect our study is unique.