Evaluation of MRI Accuracy in the Diagnosis of Perianal Fistula: Comparison with Surgical Findings

Submission: 04 October 2024 | Acceptance: 02 November 2024 | Publication: 05 December 2024

1Hira Batool, 2Dr Javaid Iqbal, 3Aiza Fatima, 4Kazim Khalid, 5Parveen Zamin, 6Hania Zahra

¹Assistant Professor Surgery, BMC/KGN MTI Bannu.

² Prof of Surgery, Continental Medical college Lahore.

 ³Ameeruddin medical college / pgmi Lahore

⁴PIMS Islamabad

⁵PIMS

⁶RIC Rawalpindi

ABSTRACT

Introduction: Precise preoperative identification of perianal fistulas is essential for effective surgical intervention. Magnetic resonance imaging (MRI) has become the preferred imaging technique; nevertheless, regional data from resource-constrained environments are still restricted. The objective of this study is to assess the diagnostic accuracy of MRI in identifying perianal fistulas, utilizing operative findings as the gold standard within a Pakistani population.

Subjects & Methods: This cross-sectional study comprised 226 patients with clinically suspected perianal fistulas who had preoperative MRI at a tertiary care facility in Sindh, Pakistan. Employing a 1.5T Philips scanner, standardized MRI protocols were executed, incorporating T1/T2-weighted sequences in three planes (axial, coronal, sagittal; 3-5mm slices) and additional PD/STIR sequences. All photos were analyzed by a single radiologist who was blinded of the clinical information. Surgical results constituted the benchmark for comparison. Diagnostic accuracy parameters (sensitivity, specificity, positive predictive value, negative predictive value) with 95% confidence intervals were computed using 2×2 contingency tables in SPSS version 23, including subgroup analyses based on age and gender.

Results. The MRI exhibited a sensitivity of 85.3%, specificity of 88.9%, and an overall diagnostic accuracy of 87.2%. The positive predictive value was 87.7%, and the negative predictive value was 86.7%. Stratified analyses demonstrated marginally superior accuracy in females (89.0% compared to 85.9%) and uniform performance across age demographics (≤45 years: 87.1%; >45 years: 87.2%).

Conclusions: The MRI demonstrates a good diagnostic accuracy for perianal fistulas, comparable to the global standards. These results endorse its regular application for preoperative planning even in resource-constrained environments. Future studies should incorporate fistula classification systems and evaluate cost-effective protocols to optimize clinical implementation.KEY WORDS:  Perianal fistula, Magnetic resonance imaging, Diagnostic accuracy, operative findings, sensitivity, specificity