Table 2. .

Stepwise Multivariable Regression Models

	Estimate	Standard Error	P-value	Variance Inflation
Linear Regression
Change in Bladder Height	0.04	0.02	0.02	1.06
Left/Right Shift	19.33	4.34	<0.0001	1.07
Superior/Inferior Shift	−2.93	1.26	0.02	1.04
3-D Shift	−6.88	1.88	0.00	1.02
Axial Rotation	−2.57	0.66	0.00	1.02
Higher Order (Quadratic) Regression
Change in Bladder Volume	0.06	0.01	<.0001	1.23
Left/Right Shift	11.87	3.25	0.00	1.18
Superior/Inferior Shift	−3.58	0.91	0.00	1.08
3-D Shift	−5.31	1.42	0.00	1.14
Axial Rotation	2.23	0.47	<.0001	1.03
Change in Bladder Volume * Left/Right Shift	−0.60	0.10	<.0001	1.32
Left/Right Shift * Superior/Inferior Shift	32.75	9.47	0.00	1.22
Left/Right Shift * Axial Rotation	−20.65	6.58	0.00	1.29
Change in Bladder Volume * Axial Rotation	−0.05	0.02	0.02	1.22