Comparative study of non-contrast and post-contrast MR fistulogram in the evaluation of fistula in Ano

  • Dr. Kavish Kapoor Department of Radiology, Military Hospital, Jalandhar Cantt.
  • Dr. Anurag Shukla Department of Radiology, Military Hospital, Jalandhar Cantt.
Keywords: Fistula in ano, MRI, perianal fistula, contrast


Background: Fistula in ano is a common inflammatory condition with significant morbidity. To evaluate the disease before planning any treatment, MRI has become a cornerstone involving both non-contrast and post contrast imaging as a routine protocol.

Aim: The current study has aims to evaluate the diagnostic efficacy of non-contrast MRI over post contrast MRI in the evaluation of perianal fistulas.

Methods: 122 patients of perianal fistulas were included in this observational study who had undergone contrast-enhanced MRI prior to surgery. Non-contrast data sets were compared with the post-contrast data sets.

Results:  The sensitivity of delineating Grade 1 perianal fistulas, as per St James university classification, on non-contrast imaging was found to be 81.03 %. The sensitivity was found to be 75%, 88.66% and 91.30% for Grade 2, 3, and 4 fistulas respectively, which increases to 100% in Grade 5 perianal fistulas.

Conclusion: On comparison of the non-contrast data set with the post-contrast images, the findings were found comparable. In higher grades of perianal fistulas, the sensitivity of evaluating the disease on non-contrast images is at par with post-contrast imaging. Contrast study, being more expensive, time-consuming and risky modality should be avoided as a routine and could be considered in low-grade perianal fistulas on case to case basis.


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DOI: 10.26838/MEDRECH.2022.9.1.577
Published: 2022-01-17
How to Cite
Kapoor K, Shukla A. Comparative study of non-contrast and post-contrast MR fistulogram in the evaluation of fistula in Ano. Med. res. chronicles [Internet]. 2022Jan.17 [cited 2023Feb.9];9(1):30-7. Available from:
Original Research Article