Diagnostic Accuracy of Magnetic Resonance Imaging(Mri) For Perianal Fistula Tract Taking Operative Findings as Gold Standard

Abstract

Objective: To find the diagnostic accuracy of magnetic resonance imaging in detection and characterization of perianal fistula taking surgical findings as gold standard. Study Design :Cross sectional study. Place And Duration of Study: Radiology Department of Pakistan Institute of Medical Sciences (PIMS), Islamabad Pakistan from January 2018 to 2020. Methodology: Magnetic Resonance Imaging procedure and protocol were clearly explained to the patients. The procedure was performed on 1.5Tesla (T)superconducting magnet (Philips) Magnetic Resonance Imaging scanner using body coil.In our study 90 patients with clinical suspicion of perianal fistula having one or more external opening were selected for Imaging evaluation. Findings were interpreted by the consultant radiologist according to St James’s University hospital classification and PARKS classification systems and correlated with surgical observations. Results: Total 90 patients were enrolled for examination. Out of these 90,83 were males (92%) and 7 were females (8%) . Mean age was 43+/-16SD. Out of 90 patients,76 were positive for perianal fistula on imaging and 74 on surgery.The calculated sensitivity was 94.9,specificity 83.3%,positive predictive value 97%,negative predictive value 71% and diagnostic accuracy was 93%. Conclusion: Magnetic Resonance Imaging is highly accurate, non invasive and less time consuming modality in preoperative evaluation, assessment and characterisation of perianal fistulas especially the complex fistulas associated with abscess and ramifications. It is especially helpful in preventing recurrences and operative complications