DIFFERENTIATION OF BENIGN AND MALIGNANT-TUMORS OF THE PAROTID-GLAND -VALUE OF PULSED DOPPLER AND COLOR DOPPLER SONOGRAPHY

To establish criteria for the differentiation of benign and malignant tumors of the parotid gland using color Doppler sonography (CDS) and p ulsed Doppler sonography (PDS) we examined 37 patients with parotid tu mors by gray-scale ultrasound, CDS and PDS. Tumor vascularization disp layed by CDS was graded subjectively on a 4-point scale (0 = no vascul arization, 3 = high vascularization). From the Doppler spectrum, the h ighest systolic peak flow velocity, the resistive index (RI), and the pulsatility index (PI) were calculated. There were 11 malignant and 26 benign tumors. Tumor vascularization by CDS was grade 0 or 1 in 88.5% of benign lesions, whereas it was grade 2 or 3 in 82% of malignant le sions (P < 0.0001). The highest systolic peak flow velocity and statis tically significantly higher in malignant lesions than in benign lesio ns. Using a threshold systolic peak flow velocity of 25 cm/s, sensitiv ity was 72% and specificity was 88% for the detection of a malignant t umor. Evaluation of tumor vascularization by CDS and PDS cannot differ entiate between benign and malignant parotid tumors with certainty. Ho wever, high vascularization and high systolic peak flow velocity in tu mor vessels should raise the suspicion of malignancy, even if tumor mo rphology on gray-scale sonography indicates a benign lesion.