Table 3. Levels of agreement and kappa coefficients for US vs. CT and for US vs. MRI stratified by WHO stages (defined by US).

US versus CT (N = 138)
Cyst stage	Agreement (%)	Expected Agreement (%)	Kappa	Std. Err.	95% CI
1	92.75	80.36	0.63	0.0791	(0.43–0.84)
2	92.75	77.27	0.68	0.0844	(0.50–0.87)
3a	92.03	78.73	0.63	0.0810	(0.43–0.82)
3b	91.30	68.52	0.72	0.0850	(0.58–0.87)
4	84.78	59.70	0.62	0.0848	(0.48–0.77)
5	98.55	72.21	0.95	0.0850	(0.88–1.00)

Cyst-stage specific kappa values: CT are more to the lower end of the category “good” (0.61–0.80), MRI at the upper end of the category “very good” (0.81–1.0).