[Color Doppler ultrasound studies of parotid tumors]

Color-coded duplex sonography is being increasingly used in the head and neck as another method of diagnosis of, for example, stenosis of arteries or veins or of hemangioma. Moreover, it is of greatest interest in having the ability to differentiate benign from malignant tumors. Since the underlying type of tumor is directly responsible for the (operative) treatment recommended we have investigated histologically proven benign and malignant parotid tumors.

Thirty-six patients (20 women, 16 men, ages 32-66 years) with parotid tumors of unknown histology were examined by means of ultrasound and color-coded duplex sonography. Afterwards, tumors were treated by complete parotidectomy. Histological results were compared postoperatively to the data from the color-coded duplex sonography.

Ultrasound B sonography. All patients were examined with a "Sonoline SI-450" (Siemens), using a 7.5 MHz transducer. Color-coded sonography. The color-coded duplex sonograph used was the Quantum 2000 (Siemens). All investigations were carried out with a 7.5 MHz transducer. Criteria of color-coded duplex sonography. Criteria of the investigation were the qualitative range of color distribution as an indication of vascularization and measurement of perfusion velocity--as far as possible--with mean pulsatility indices. The mean pulsatility index represented peripheral resistance and was proportional to it. All data were collected from three areas in the center of the tumor and tumor margins, respectively. Tumors selected were 17 histologically proven pleomorphic adenomas, 15 adenolymphomas and 4 adenoid cystic carcinomas. RESULTS. In comparing perfusion velocity and mean pulsatility indices, no significant difference was detected between pleomorphic adenomas and adenolymphomas. A loss of perfusion and color was seen in both tumor types, although it occurred more often in the adenolymphomas. These cystic areas in most cases had already been clearly detected with normal B-scan sonography. In two of the four malignancies there were no obvious differences to the benign tumors. In the other two cases of malignancy a pronounced vasularization was detected and, therefore, an extended distribution of color. This finding together with decreased perfusion velocity and low mean pulsatility indices indicated low peripheral resistance.

At this point it is not possible routinely to utilize color-coded duplex sonography as an accurate indicator of underlying pathology of parotid neoplasms. A differentiation among different types of benign tumors is not possible using the technique, nor can malignancies be recognized definitively by this method.