Table 4.

Rate of knee MRI claims by rate of MRI-scanners, adjusted for year and geographic region: linear regression analysis

Explanatory variable	Regression coefficient	95 % CI
Rate of MRI-scanners*	744	201, 1287
Year
2002	-2046	-6024, 1931
2003	-1081	-3490, 1328
2004 (reference)	0
Geographic region
North	-5079	-7887, -2271
Central	-7234	-9478, -4991
West	-400	-6242, 5443
South/East (reference)	0

MRI = magnetic resonance imaging.

CI = confidence interval.

* P = 0.017. Intercept (95% CI) = 2003 (-10906, 14913).