[en] Objective: To evaluate the effect of arterial input and ROI selection on the perfusion CT parameters of parotid tumors. Methods A deconvolution-based software(Philips ADW4.5) was used to perform perfusion calculations on 12 parotid tumor patients. Blood flow(BF), blood volume(BV), and peak enhancement index(PEI) of different arterial inputs and ROI selection were recorded. These values were compared using one-way ANOVA. Independent sample t-test was performed to compare the values of adenolymphoma and non-adenolymphoma. Results: No significant difference was observed among BF, BV, and PEI obtained when external carotid artery(ECA), internal carotid artery(ICA), and common carotid artery(CCA) were used as input arteries(F = 0.012, 0.007 and 0.233, all P > 0.05). Similarly, no significant difference was observed among the perfusion parameters of different ROIs of lesions(F = 0.220, 0.033, and 0.283, all P > 0.05). When ECA was selected as arterial input, the area of ROI was approximately S80%, and PEI had the best diagnostic effect for adenolymphoma differential diagnosis. Conclusions: Arterial input selection and area of ROI had no significant effect on perfusion CT calculation of parotid tumor. However, ECA and S80% of ROI selected for perfusion post-processing might facilitate parotid adenolymphoma diagnosis. (authors)