MRI OF COMPLICATED ANAL FISTULAS - COMPARISON WITH DIGITAL EXAMINATION

Objectives: The assessment of complicated anal fistulae is based on di gital examination. Our objective was to study the potential role of MR I in this setting by comparing preoperative digital examination with M RI. Materials and Methods: Digital examination and MRI were prospectiv ely and blindly interpreted in 13 patients with complicated anal fistu lae. Surgical findings were used as standard. Results: Complete agreem ent between the results of digital examination and the surgical findin gs was observed in 8 patients and between the results of MRI and the s urgical findings in 12 patients. Digital examination misclassified two low transsphincteric fistulae as high transsphincteric and missed hig h secondary extensions or abscesses in three other patients. Magnetic resonance misclassified only one suprasphincteric fistula as low trans sphincteric and did not overlook high secondary extensions or abscesse s. Conclusion: These findings suggest that MRI may show abnormalities not detected by preoperative digital examination.