Diffusion-weighted magnetic resonance imaging (DWI) is routinely used in prostate cancer assessment, but suffers from image distortions primarily due to the tissue-air interface at the rectal cavity. Readout-segmented echo planar imaging (RESOLVE) improves image quality through segmented acquisition of k-space, increasing bandwidth in the phase direction. However, distortions of several millimeters may still exist in RESOLVE images. This study quantified distortions in a prostate phantom by varying the number of RESOLVE segments and using field mapping correction techniques. Field mapping correction decreased image distortion by 28% compared to the 7-segment RESOLVE scan.