Fig. 3

Illustration of the definition of “C-G discrepancy”. On the top image, the red point shows the center of urethra-C defined as coordinates Xc and Yc, and the blue point shows the center of urethra-G defined as coordinates Xg and Yg. The “C-G discrepancy” is calculated from the coordinates of the center of the ROI for urethra-C and urethra-G along the antero-posterior direction and the left-right direction. Two-dimensional (2D) direct distance between urethra-C and urethra-G are calculated using these distances. On the lower box, the definition of the “C-G discrepancy” is shown. R↔L, left-right direction; A↔P, anteroposterior direction; direct distance, 2D direct distance