Delineation of anatomic proximal 2 - cm SV. A. Locating a point 2-cm from the starting point of the SV on its central line (P2), cut lines in the oblique coronal plane are centered at P2 and adjusted until the sagittal cut plane becoming tangent to the central line. B. Oblique sagittal plane including the SV. C. Cut planes orthogonal to the central line. H2 and L2 indicate the points with maximum and minimum vertical distance to the starting plane of the SV. “*” indicates the vas deferens. D. Maximum diameter (R2) of the 2-cm cross section (R2).