Magnetic resonance imaging in the workup of patients with perianal fistulas

Egyptian Journal of Radiology and Nuclear Medicine

Table 10 Interobserver agreement between observer A and B for findings in MRI

Findings	Observer		K degree	95% CI	P value	Percentage (%)
	A	B	K degree	95% CI	P value	Percentage (%)
Secondary tract
Present	8 (16%)	7 (14%)	0.89	0.78–0.9	< 0.0001	92
Absent	42 (84%)	43 (86%)	0.89	0.78–0.9	< 0.0001	92
Site of internal opening
6–8 O’clock	27 (54%)	28 (56%)	0.93	0.81–0.98	< 0.001	96
3–5 O’clock	8 (16%)	15 (30%)
12–2 O’clock	14 (28%)	29 (58%)
9–11 O’clock	6 (12%)	11 (22%)
Presence of abscess
Yes	10 (20%)	10(20%)	1	1	< 0.001	100
No	40 (80%)	40 (80%)	1	1	< 0.001	100
Site of abscess
Intersphincteric region	5 (10%)	5 (10%)	0.98	0.91–1	< 0.001	98
Ischiorectal fossa	3 (6%)	3 (6%)
Around anal canal	2 (4%)	3 (6%)
Supralevator region	1 (2%)	0
St. James classification
Grade I	21(42%)	21 (42%)	0.94	0.89–0.98	< 0.001	96
Grade II	9 (18%)	9 (18%)
Grade III	8 (16%)	9 (18%)
Grade IV	12 (24%)	11 (22%)
Parks classification
Extrasphincteric	4 (8%)	4 (8%)	0.93	0.81–0.98	< 0.001	96
Intrasphincteric	30 (60%)	29 (58%)
Suprasphincteric	4 (8%)	5 (10%)
Trans-sphincteric	12 (24%)	12 (24%)

P value was significant if < 0.05. CI Confidence interval
Interobserver agreement: Interobserver agreement between 2 senior radiologists on the interpretation of images was measured using the kappa statistic, Kappa values: < 0 = no agreement, 0.0–0.20 = slight agreement, 0.21–0.40 = fair agreement, 0.41–0.60 = moderate agreement, 0.61–0.80 = good agreement, and 0.81–1.00 = very good agreement