Contrast-enhanced color Doppler sonography of parotid gland tumors.

The objective of the present study is to assess the potential of color Doppler sonography in imaging tumors of the parotid gland enhanced by application of ultrasound contrast agents. To this end 26 patients with tumors of the parotid gland were investigated. The color Doppler signal areas before and after administration of Doppler signal-enhancing agent (Levovist, Schering, Germany) were determined by means of computer-assisted analysis, and the relevant parameters were evaluated. The tumors can be classified as follows: 11 pleomorphic adenomas, 8 adenolymphomas and two squamous cell carcinomas of the parotid gland, two lymph nodes, one adenoma, one neurinoma of the facial nerve and one non-Hodgkin's lymphoma. Before the administration of Doppler signal-enhancing agent, the adenolymphomas showed a significantly stronger Doppler signal area as compared to the pleomorphic adenomas. The maximum color Doppler signal area after administration of Doppler signal-enhancing agent showed no difference within both groups. If one considers the relative change in the Doppler signal area before and after applying enhancing agent, however, a significantly stronger enhancement of perfusion (increase in Doppler signal area) is noted within pleomorphic adenomas. The changes in the Doppler signal area after administration of signal-enhancing agent show a different course depending on the histology of the investigated tumors.