To explore the percentage enhancement wash-out ratio (PEW) and relative PEW (RPEW) of low-dose multi-phasic computed tomography (CT) in distinguishing benign from malignant parotid gland tumours.
This study was approved by the ethics committee, and informed patient consent was obtained. 51 patients with parotid tumours proven by histopathology received CT, including 18 with pleomorphic adenomas, 14 with Warthin’s tumours and 19 with malignant tumours. Size and attenuation of parotid tumours were measured. Compared with 5-min attenuation, the 30-s and 90-s PEW (PEW 30, PEW 90) and RPEW (RPEW 30, RPEW 90) were calculated.
There was a significant difference in PEW 30, RPEW 30, PEW 90 and RPEW 90 in the parotid neoplasms groups ( P < 0.01), and statistical significance existed simultaneously in pleomorphic adenomas vs malignant tumours and Warthin’s tumours vs malignant tumours according to SNK-q test. The optimal diagnosis results of malignancy with 100% specificity (32/32) was obtained by using a combination of the following criteria: −70% > PEW 30 < 36%, −30% > PEW 30 < 19%, PEW 90 > 12%, and the sensitivity (74%) for diagnosis of malignancy was yield.