Characteristics of pleomorphic adenomas, adenolymphomas, and malignant tumors of the salivary glands on color doppler ultrasonography and contrast enhanced ultrasonography

OBJECTIVE: To provide a comprehensive description of the quantitative and qualitative characteristics of pleomorphic adenomas, adenolymphomas, and malignant tumors of the salivary glands on color doppler ultrasonography and contrast-enhanced ultrasonography (CEUS). PATIENTS AND METHODS: 64 patients with 35 pleomorphic adenomas, 24 adenolymphomas, and 12 malignant tumors were enrolled in this study. All patients were examined by color doppler ultrasonography and CEUS before operation. In color Doppler ultrasonography, degree of vascularity, peak systolic velocity (PSV) and the vascular resistance index (RI) were obtained. In CEUS, type of enhancement, rim enhancement and area of enhancement were assessed. After the time-intensity curves (TIC) were drawn. the time to peak enhancement (TTP), peak intensity (PI) and the time from peak to one half (TFP) were calculated for the tumors and surrounding salivary parenchyma. Postoperatively, histopathologic examination of surgical specimens was used as the gold standard. RESULTS: Color Doppler ultrasonography showed no significant differences in PSV between tumors, significantly less adenolymphomas had Grade 0-1 vascularity compared to pleomorphic adenomas, and the RI was significantly lower in adenolymphomas compared to pleomorphic adenomas and malignant tumors. CEUS had acceptable diagnostic sensitivity, specificity, and accuracy for differential diagnosis of pleomorphic adenomas and adenolymphomas based on the diagnostic criteria of rim enhancement and slow wash-out rate, respectively. The sensitivity, specificity. and accuracy for differential diagnosis of malignant tumors based on the diagnostic criteria of an ill-defined enhancement margin, an enlarged enhancement area or a fast wash-in rate were also satisfactory. CONCLUSIONS: Accurate diagnosis of salivary gland tumors in clinical practice can be increased using color Doppler ultrasound and CEUS in combination with a case history and other imaging.