Three-dimensional endoanal ultrasonographic assessment of an anal fistula with and without H2O2 enhancement

Table 2 Results of physical examination and 3D-EAUS findings in classification of secondary extensions

	Classification based on surgical findings (No. of secondary extensions detected)				Overall accuracy
	Absent (37)	Intersphincteric (7)	Ischiorectal (19)	Supralevator (3)
Physical examination
Absent	241	1	3
Intersphincteric	5	41	3	2
Ischiorectal	8	2	121		62.1% (41/66)a
Supralevator	0	0	1	11
3D-EAUS
Absent	321	0	2	1
Intersphincteric	2	51	1	2
Ischiorectal	3	2	161	0	81.8% (54/66)b
Supralevator	0	0	0	11
H2O2 3D-EAUS
Absent	331	0	1	1
Intersphincteric	1	51	1	0
Ischiorectal	3	2	171	0	86.4% (57/66)c
Supralevator	0	0	0	21

¹Absolute agreement; P = 0.01 between a and b, P = 0.001 between a and c, P = 0.482 between b and c.