Table 4.

Overall and pairwise interobserver agreement of the applicable features of Chiari II malformation

Feature	κ value				Agreement (%)		Disagreement (%)	No.
	Overall	Pairwise			All rated	All rated
		A–B	A–C	B–C	‘Present’	‘Absent’
Sagittal plane
Downward herniation cerebellum	0.85	0.90	0.87	0.77	29	61	10	69
Downward herniation vermis	0.72	0.84	0.66	0.67	20	63	17	66
Downward herniation tonsil	0.85	0.85	0.89	0.80	24	67	9	64
Upward herniation cerebellum	0.56	0.66	0.57	0.42	5	82	13	63
Downward displacement medulla	0.83	0.88	0.83	0.78	19	72	9	65
Downward displacement pons	0.75	0.96	0.64	0.60	12	76	12	65
Downward displacement fourth ventricle	0.84	0.87	0.85	0.80	17	75	8	65
Medullary kinking	0.88	0.94	0.88	0.81	12	83	5	64
Flattened pons	0.70	0.70	0.72	0.67	19	62	19	69
Abnormal width fourth ventricle	0.85	0.92	0.81	0.81	21	70	9	67
Hypoplastic tentorium	0.84	0.86	0.76	0.91	19	73	8	60
Abnormal course straight sinus	0.73	0.85	0.61	0.75	17	71	12	55
Beaked tectum	0.90	0.92	0.88	0.89	22	72	6	69
Enlarged massa intermedia	0.10	0.27	0.00	0.03	4	26	70	66
Axial plane
Cerebellum wrapped around brainstem	0.50	0.95	0.18	0.20	4	73	23	55
Small fourth ventricle	0.85	0.87	0.91	0.78	23	68	9	56
Enlarged fourth ventricle	–a	–a	–a	–a	2	98	0	53
Enlarged massa intermedia	–a	–a	–a	–a	0	100	0	1
Coronal plane
Indentation	0.70	0.81	0.63	0.63	6	86	8	48
Hypoplastic tentorium	–a	–a	–a	–a	5	85	10	20
Gyral interdigitation	0.63	0.61	0.76	0.54	11	71	18	44

Overall κ value > 0.8 indicating almost perfect agreement are presented in italics A observer A, B observer B, C observer C

^aκ value could not be calculated, because one or more counts were too small