[Magnetic resonance imaging in perianal Crohn's disease].

Magnetic resonance imaging (MRI) was undertaken in a prospective study of 34 consecutive patients (21 women, 13 men; median age 31 [18-53] years) suspected of having active perianal Crohn's disease. The results of the investigation were compared with those obtained by independent observers on proctological and intraoperative examination (n = 31). A total of 58 fistulas and 21 abscesses were noted intraoperatively, 47 fistulas and all 21 abscesses by MRI, and 40 fistulas and 13 abscesses proctologically. The proctological examination proved to be more sensitive in demonstrating short subcutaneous or anovaginal fistulas (three of four subcutaneous and two of five anovaginal fistulas were not shown by MRI). Intersphincteric, ischiorectal and supralevator involvement was shown better by MRI. These results indicate that in perianal Crohn's disease MRI is a useful addition to proctological examination.