Abstract
Objectives: The assessment of complicated anal fistulae is based on digital examination. Our objective was to study the potential role of MRI in this setting by comparing preoperative digital examination with MRI.
Materials and Methods: Digital examination and MRI were prospectively and blindly interpreted in 13 patients with complicated anal fistulae. Surgical findings were used as standard.
Results: Complete agreement between the results of digital examination and the surgical findings was observed in 8 patients and between the results of MRI and the surgical findings in 12 patients. Digital examination misclassified two low transsphincteric fistulae as high transsphincteric and missed high secondary extensions or abscesses in three other patients. Magnetic resonance misclassified only one suprasphincteric fistula as low transsphincteric and did not overlook high secondary extensions or abscesses.
Conclusion: These findings suggest that MRI may show abnormalities not detected by preoperative digital examination.