MRI of pouch-related fistulas in ulcerative colitis after restorative proctocolectomy.
OBJECTIVE
Our purpose was to determine the value of MRI in diagnosing pouch-related fistulas in patients with ulcerative colitis and to compare pulse sequences with and without contrast enhancement in their performance of visualization.


METHODS
Forty-four patients with pelvic symptoms after restorative proctocolectomy underwent MRI. All 26 patients with pouch-related fistulas were treated surgically; 18 patients with pouchitis were treated conservatively. MRI was performed at 1.0 T with T1-weighted FLASH sequences before and after administration of Gd-DTPA, T2-weighted and proton density-weighted turbo SE sequences, and a T2-weighted fat saturation sequence. Images were analyzed for the presence of fistula; pulse sequences were additionally compared for best visualization on a four point scale of diagnostic confidence.


RESULTS
MRI detected 23 of 26 cases of fistulas; there were no false-positive diagnoses. Surgery revealed fistulas in three cases in which no pathology was found on MRI. Two patients had a short sinus tract at the pouch-anal anastomosis, and a third patient had a pouch-vaginal fistula. The Gd-enhanced FLASH sequence obtained the highest score, and second best was the T2-weighted fat saturation technique.


CONCLUSIONS
MRI is a valuable technique for diagnosing pouch-related fistulas, However, there are limitations in detection of short sinus tracts and pouch-vaginal fistulas. Highest diagnostic confidence is obtained with a Gd-enhanced FLASH sequence, which might be helpful after pelvic surgery or if the fact saturation technique is equivocal.
Department of Diagnostic Radiology, University of Heidelberg, Germany.
M
M
Libicher
J
J
Scharf
A
A
Wunsch
J
J
Stern
M
M
Düx
G W
GW
Kauffmann
D000328:Adult; D003093:Colitis, Ulcerative / Q000150:complications* / Q000175:diagnosis / Q000601:surgery; D003108:Colonic Diseases / Q000175:diagnosis* / Q000209:etiology; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007412:Intestinal Fistula / Q000175:diagnosis* / Q000209:etiology; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis* / Q000209:etiology; D016737:Proctocolectomy, Restorative / Q000009:adverse effects*; D011446:Prospective Studies; D018709:Statistics, Nonparametric
D003287:Contrast Media; D019786:Gadolinium DTPA