Differentiation of parotid gland tumors with contrast-enhanced ultrasound.

PURPOSE: Pilot study to evaluate a new ultrasound (US) technique for differentiating parotid cystadenolymphoma (CL) from pleomorphic adenoma (PA).

MATERIALS AND

METHODS

27 patients presenting with a palpable lesion of the parotid gland were examined by B-mode US. All patients underwent US examination with administration of 2.4 ml US contrast medium (USCM). The intratumoral time-to-peak was determined. The contrast medium inflow curves from the tumor and parotid parenchyma were compared by using AUC analysis and compared with histology.

RESULTS

Histology demonstrated cystadenolymphoma in 9 cases (CL group) and pleomorphic adenoma in 9 (PA group). The intratumoral time-to-peak in the PA group was markedly longer than in the CL group (26.8 +/- 11.1 sec versus 22.6 +/- 5.1 sec, p < 0.05). AUC analysis for the tumor area demonstrated a significant difference between the PA group (30.3 +/- 24.3 dB/area) and the CL group (77.4 +/- 45.6 dB/area, p < 0.05).

CONCLUSION

The standardized analysis of USCM inflow curves has the potential to differentiate cystadenolymphoma and pleomorphic adenoma. More patient numbers, perhaps with blinded readers, would allow reliable diagnostic determination for future studies.