Anal sphincter defects in patients with fecal incontinence: endoanal versus external phased-array MR imaging.
OBJECTIVE
To prospectively compare external phased-array magnetic resonance (MR) imaging with endoanal MR imaging in depicting external and internal anal sphincter defects in patients with fecal incontinence and to prospectively evaluate observer reproducibility in the detection of external and internal anal sphincter defects with both MR imaging techniques.


METHODS
The medical ethics committees of both participating hospitals approved the study, and informed consent was obtained. Thirty patients (23 women, seven men; mean age, 58.7 years; range, 37-78 years) with fecal incontinence underwent MR imaging with both endoanal and external phased-array coils. MR images were evaluated by three radiologists with different levels of experience for external and internal anal sphincter defects. Measures of inter- and intraobserver agreement of both MR imaging techniques and of differences between both imaging techniques were calculated.


RESULTS
Both MR imaging techniques did not significantly differ in the depiction of external (P > .99) and internal (P > .99) anal sphincter defects. The techniques corresponded in 25 (83%) of 30 patients for the depiction of external anal sphincter defects and in 28 (93%) of 30 patients for the depiction of internal anal sphincter defects. Interobserver agreement was moderate to good for endoanal MR imaging and poor to fair for external phased-array MR imaging. Intraobserver agreement ranged from fair to very good for both imaging techniques.


CONCLUSIONS
External phased-array MR imaging is comparable to endoanal MR imaging in the depiction of clinically relevant anal sphincter defects. Because of the weak interobserver agreement, both MR imaging techniques can be recommended in the diagnostic work-up of fecal incontinence only if sufficient experience is available.
Terra
Maaike P
MP
Department of Radiology, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands. m.p.terra@amc.uva.nl
Beets-Tan
Regina G H
RG
van Der Hulst
Victor P M
VP
Dijkgraaf
Marcel G W
MG
Bossuyt
Patrick M M
PM
Dobben
Annette C
AC
Baeten
Cor G M I
CG
Stoker
Jaap
J
D000328:Adult; D000368:Aged; D001003:Anal Canal / Q000503:physiopathology*; D005242:Fecal Incontinence / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results