Fig. 4

Examples of U-Net segmentation performance influenced by prostate morphology. In case a, the prostate is hyperplastic with increased prostate volume and the peripheral zone (PZ) is still identifiable; the U-Net model shows good segmentation for both the central gland (CG) and PZ, with Dice similarity coefficients (DSCs) of 0.953 and 0.894, respectively. In case b, the PZ is compressed by CG, with increased CG/PZ volume ratio; the segmentation of PZ is challenging, with a DSC of 0.543. In case c, despite tumor involving both PZ and CG (arrow heads) and blurring the boundary between PZ and CG, the U-Net model can generate the zonal outline, thereby offering benefit for the localization of prostate lesions