To assess the value of multi-modal ultrasound in the differential diagnosis of focal lesions of the salivary gland.

A retrospective analysis was conducted on the clinical and ultrasonic imaging data of 128 patients with focal lesions of salivary gland who were cured at the First Medical Center of PLA General Hospital from January 2018 to December 2020. Those patients were divided into either a benign group or a malignant group based on the pathology results as golden standard. All the patients underwent conventional ultrasound (US), real-time ultrasound elastography (RTE), and contrast enhanced ultrasound sonography (CEUS), and the features of all ultrasound images were recorded and analyzed. The χ² test was used to compare the multimodal ultrasound image characteristics of the lesions between the two groups, and the receiver operating characteristic (ROC) curve was plotted. The diagnostic efficacy of US, US+RTE, US+CEUS, and US+RTE+CEUS in the diagnosis of focal salivary gland lesions was assessed by the area under the ROC curve (AUC).

Among the 128 patients included, 85 were confirmed to have benign lesions through pathological diagnosis, and 43 had malignant lesions. The incidence of sharpness of the border and regularity of the shape on US was significantly higher in the benign group than in the malignant group (P＜0.001). In the malignant group, 46.5% (20/43) of cases were classified as grade Ⅲ by RTE and 72.1% (31/43) were classified as type IIc by CEUS; the corresponding percentages in the benign group were only 16.5% (14/85) and 11.8% (10/85), respectively. When positivity obtained by either US or RTE was used to diagnose malignancy, the sensitivity, specificity, AUC, and Youden's index were 0.767, 0.800, 0.784, and 0.567, respectively. When positivity obtained by either US or CEUS was used to diagnose malignancy, the sensitivity, specificity, AUC, and Youden's index were 0.791, 0.882, 0.837, and 0.673, respectively. When positivity obtained by any one of US, RTE, and CEUS was used to diagnose malignancy, the sensitivity, specificity, accuracy, negative predictive value, and positive predictive value were 0.767, 0.941, 0.883, 0.868, and 0.889, respectively, and the AUC and Youden's index were 0.854 and 0.708, respectively.

Combined application of multi-modal ultrasound can improve the differential diagnosis of benign and malignant focal lesions of the salivary gland.