1. + Are MRI scans of any use prior to surgery for anal fistulae Authors: Patrick Jasinski, Deepak Pai, Geeta Kaur Presented by: Wajiha Arshad

2. + Introduction Accurate identification of anal anatomy and management is crucial for a successful outcome Adequate evaluation: Radiologic approach Surgical approach via examination under anesthesia (EUA)

3. + Examination under anesthesia Requires a skilled and dedicated surgeon proctologist with the use of hydrogen peroxide (H2O2) Picture shows anorectal fistula with packed abscess cavity and seton insertion

4. + Examination under anesthesia Picture shows complex anorectal fistula with fistula probes inserted into numerous tracts

5. + Introduction EUA has long been the gold standard for evaluation and classification of perianal fistulae Recent studies suggest that EUA may misclassify perianal fistulae in approx. 10% of patients, with potential to adversely affect therapeutic outcomes MRI has now become a powerful tool in the evaluation of anal anatomy

6. + Aims and Method Evaluate the use and accuracy of MRI compared with the EUA findings. Retrospective analysis of all patients in our unit Clinical diagnosis of fistula in ano Underwent MRI as well as EUA for diagnosis and management Period of 6 months Included findings of first EUA after MRI in analysis MRI scans independently reviewed and reported by single consultant radiologist Blinded to the results of EUA

7. + Results Identified 38 patients in total 8 excluded due to incomplete data 1 later identified as not having had an MRI

8. + Results

9. + Complete agreement between MRI and EUA findings in 13 patients (44.83%)

10. + Results Some correlation in 6 (20.69%) No correlation in 10 (34.48%) No fistula found in MRI, but was found on EUA in 7 (70%) Remaining 3 had a ‘fistula’ tract seen on MRI, but no tract identified on EUA

11. + Discussion Patients with complex anal fistula disease MRI is an important adjunct Delineating disease location and extent Relationship to sphincter muscles Planning management Study by Buchanan et al regarding the use of MRI in recurrent fistulae (Lancet 2002); surgery and MRI agreed in 56% We found concurrence which was total in 45% and partial in 21% of patients We included however all fistula patients in our study

12. + Conclusion We recommend the use of MRI scans reported by a single trusted radiologist in all patients with recurrent fistula, complex disease on initial examination and Crohn’s disease, prior to surgery.

13. + References [MR Imaging Classification of Perianal Fistulas and Its Implications for Patient Management1] Morris et al. RadioGraphics Vol. 20, No. 3: 623-635