MAGNETIC RESONANCE IMAGING;

Perianal fistula is defined as an abnormal communication channel between analcanal and perianal skin. Among all the imaging tools Magnetic resonance imaging (MRI) isof choice in the diagnosis and management of perianal fistulas. Objectives: “To determinethe diagnostic accuracy of MR imaging in detection of perianal fistulas and comparing it withper operative findings”. Peroperative findings are taken as gold standard. Place and Durationof Study: This study was carried out in Diagnostic Radiology, Pakistan Institute of MedicalSciences (P.I.M.S) Islamabad, over a period of nine months from 01-02-2012 to 31-10-2012. Forthis collaboration was made with the Department of General Surgery P.I.M.S and Departmentof gynecology (MCH center) PIMS and gastroenterology Department. Patients and Methods:A total of 95 patients were included in study having perianal fistulas on clinical examination.MRI was performed in the patients and T1-weighted fast spin echo (T1W FSE) images weretaken before and after gadolinium injection. Fat suppressed T2-weighted fast spin echo (T2WFSE) images were obtained in all three planes including transverse, sagittal and coronal. Allthe scans were viewed by a single consultant radiologist to avoid observer bias. Results: Outof 95, 81 patients (85.3%) were male and 14 (14.7%) were female. Sensitivity, specificity andaccuracy of magnetic resonance imaging (MRI) was 96.2%, 75.0% and 92.6%, respectively.Positive predictive value was 95.0% and negative predictive value was 80.0%. Conclusion: ourstudy proves that among imaging modalities MRI is of choice for preoperative assessment ofperianal fistulas. It provides highly accurate, noninvasive and relatively very less time consumingmeans of performing pre-operative evaluation, specially the complex, branching fistulas. Thisdiagnostic accuracy not only helps in surgical cure but avoids recurrence and post-operativecomplications like fecal incontinence