PURPOSE: To investigate the feasibility of using diffusion-weighted (DW) echo-planar imaging (EPI) for differentiating primary parotid gland tumors. MATERIAL AND METHODS: Fifty consecutive patients with a suspected primary tumor of the parotid gland were examined with a DW EPI sequence (TR 1,500 msec, TE 77 msec, field of view 250 x 250 mm, pixel size 2.10 x 1.95 mm, section thickness 5 mm). The b factors used were 0, 500, and 1,000 sec/mm (2). Apparent diffusion coefficient (ADC) maps were digitally transferred to MRIcro (Chris Rorden, University of Nottingham, Great Britain) and evaluated with a manually placed irregular region of interest (ROI) containing the entire tumor. Additionally, the contralateral, non affected parotid gland was measured and a circular ROI containing 100 - 200 pixels was placed in the cerebrospinal fluid (CSF) next to the spinal cord in every patient. For comparison of the results, the two-tailed Student's t test was used, based on the median ADC values for each patient, and a p-value
