Table 4. Independent predictors of the width of the kidneys, pelves and ureters on both sides.

	Predictor	Significance (p-value)	Regression coefficient β
Width of the pelvis on the right side	Width of the pelvis on the left side	<0.001	0.454
	Female gender	<0.001	0.156
	Height	0.001	0.096
	Age	0.002	0.094
Width of the pelvis on the left side	Width of the pelvis on the right side	<0.001	0.472
	Calculi	0.001	0.095
	Rotation of the upper pole in dorsal position	0.010	0.071
	Parapelvine cysts	0.023	0.062
Width of the ureter on the right side	Width of the pelvis	<0.001	0.238
	Calculi	0.001	0.1
	Width of the parenchyma	0.002	0.094
	Level of the centre of the pelvis in relation to the spine (cranial position)	0.004	0.088
	Diameter of the caval vein	0.017	0.072
Width of the ureter on the left side	Width of the pelvis	<0.001	0.251
	Width of the parenchyma	0.001	0.111
	Number of crossing arteries	0.009	–0.082