Tamada T, et al. - The reproducibility and diagnostic performance of 2D and 3D ROIs for prostate apparent diffusion coefficient (ADC) measurements were compared in this study. It was concluded that the utilization of a 3D ROI did not improve intrareader or interreader reproducibility or diagnostic performance compared with the utilization of a 2D ROI for prostate ADC measurements. They also noted that the interreader reproducibility of 2D ROIs was suboptimal nonetheless.