Value of MRI performed with phased-array coil in the diagnosis and pre-operative classification of perianal and anal fistulas.
OBJECTIVE
To assess the value of MRI performed with phased-array coil in the diagnosis and preoperative staging of perianal and anal fistulas.


METHODS
20 patients (13 with Crohn's disease) with clinical evidence or suspicion of anal fistulas underwent pelvic MRI (1.5 T) performed with phased-array coil. Images were obtained in the axial and coronal planes using TSE T2-weighted high resolution sequences with and without fat suppression, T2-weighted HASTE and T1-weighted FLASH sequences, with and without fat suppression, before and after gadolinium enhancement. The following parameters were considered: presence of a fistula and relation with the sphincters, and presence of abscesses or complications. All patients underwent surgery. The MRI and surgical findings were assessed using the Park's fistula-in-ano classification and the St. James MR imaging classification of perianal fistulas. Surgery was considered the gold standard.


RESULTS
MRI documented no evidence of fistula in 2 patients, intersphinteric fistulas in 5 (grade 1 and 2 St. James), trans-sphincteric fistulas in 9 (grade 3 and 4 St. James), translevator in 2 (grade 5) and complex ano-rectum-vaginal fistulas in 2. Concordance with surgery was 90%.


CONCLUSIONS
MRI is an accurate technique for the identification and classification of anal and perianal fistulas and their complications. In our experience the phased-array coil offers both high field of view and spatial resolution, enabling the demonstration of perianal pathology.
Maccioni
F
F
Istituto di Radiologia, Policlinico Umberto I, Università degli Studi di Roma La Sapienza, Rome, Italy. chiarilu@tiscalinet.it
Colaiacomo
M C
MC
Stasolla
A
A
Manganaro
L
L
Izzo
L
L
Marini
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D003424:Crohn Disease / Q000150:complications / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods; D008297:Male; D008875:Middle Aged; D011351:Proctoscopy; D012003:Rectal Fistula / Q000145:classification / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D012680:Sensitivity and Specificity; D013997:Time Factors