Role of MRI in the Diagnosis and Pre-Operative Classification of Perianal and Anal Fistulas - A Cross-Sectional Study, Southern Rajasthan

Abstract

BACKGROUND Perianal fistulas account for a substantial discomfort and morbidity to the patient thus affecting productive man hours and quality of life. Accurate pre-operative assessment of course of the primary fistulous track and secondary extension or abscesses is required for successful surgical management of anal fistulas. The purpose of this study was to diagnose and classify pre-operative perianal fistulas. METHODS This is a cross-sectional study at Department of Radiodiagnosis in a tertiary level hospital of southern Rajasthan from November 2018 to November 2020. The study included a total of 50 patients referred to department of radiology for magnetic resonance imaging (MRI). Statistical analysis was done using chi square test and student t test. RESULTS Out of these patients, 56 % were having secondary tract on MRI, 12 % patients were having abscess and 4 % were having horseshoe abscess on MRI. The commonest type of ano-rectal fistula encountered in the study was Grade -II seen in 32 %. CONCLUSIONS MRI is a highly accurate, rapid and non-invasive tool in pre-operative evaluation of the perianal and anal fistulas. MRI evaluation and classification of perianal fistulae has a high degree of diagnostic accuracy. The use of MRI for the diagnosis and classification of perianal fistula can provide reliable information which has both pre-operative and prognostic value. St James University Hospital classification, which is an MR imaging-based grading system for perianal fistula is very useful for effective radiological-surgical communication thus contributing to improved patient care and reduced rate of recurrence. KEYWORDS MR Fistulogram, Perianal Fistula, Anal Fistula, Fistula Classification, Fistulography