Table 4.

Distance between the right and left common iliac veins at the level of the promontorium.

Distance	Level of S1 cranial endplate (mm)	1 cm caudal to S1 cranial endplate (mm)	P value
R-CIV/L-CIV	43.00 ± 8.73	47.00 ± 15.90	0.015
R-CIV/P	24.00 ± 4.61	26.00 ± 8.12	1.091
L-CIV/P	19.00 ± 6.46	21.00 ± 7.14	0.018
P value (R-CIV/P versus L-CIV/P)	0.001	0.003

Data are presented as mean ± standard deviation. R-CIV and L-CIV: distance between the right and left common iliac veins; R-CIV/P: distance between the right common iliac vein and the center of promontorium; L-CIV/P: distance between the left common iliac vein and the center of promontorium.