Ultrasonography Combined With Sonoelastography Strain Ratio for the Differentiation of Parotid Masses

Accurate preoperative differentiation of benign and malignant parotid masses is crucial for determining appropriate treatment strategies. We aimed to investigate the value of combining conventional ultrasonography (US) with the measurement of sonoelastographic strain ratio (SR) for the preoperative differentiation of parotid masses.

We conducted a single-center retrospective study of 514 patients who had undergone excision of parotid gland masses from June 2019 to June 2023. Patients underwent preoperative high-resolution imaging, which was performed to record SRs between lesional and peri-lesional tissue.

Histopathologic results disclosed benign lesions in 443 patients and malignant neoplasms in 71 patients. Pleomorphic adenoma and Warthin tumor were the most prevalent histopathologic diagnoses in the benign group. Prevalence rates of specific malignant tumor types did not differ significantly. Lesion shapes differed significantly between benign and malignant lesions, but border definition, echogenicity, and vascularization were similar. The sensitivity, specificity, accuracy, positive and negative predictive values, and diagnostic performance of US + SR, exceeded those of either US or SR alone. The optimal cutoff point (2.25) was computed by using receiver operating characteristics analysis (area under the curve 0.908). The sensitivity, specificity, and accuracy of the strain index values were 88.7, 83.8, and 84.2%, respectively, when the optimal cutoff point of 2.25 was used.

SR combined with US can more accurately differentiate benign from malignant parotid gland masses than either US or SR alone; and can thereby facilitate the optimal design of diagnostic and therapeutic interventions.