The Role of Diagnostic Medical Imaging Techniques in the Evaluation of Perianal Fistula: A Review

Abstract

The fistula in ano or perianal fistula is one of the common fistulae noted in routine surgical and clinical practice. It has the tendency to reoccur even after surgery, which is due to missed pathological tract or tissue during surgical exploration. An adequate pre-surgical mapping is a necessity for giving an excellent surgical outcome and choosing an appropriate surgical technique for treating various fistulas. So, medical imaging modalities like X-ray fistulography, endoanal ultrasonography, computed tomography fistulography, and the magnetic resonance fistulography were used for assessing fistula. Among these, magnetic resonance fistulography is the commonly preferred diagnostic medical imaging technique for interpreting the fistula as it has higher resolution on soft tissues, non-usage of ionizing radiation, which reduced the threat of radiation-induced cancer, and non-invasive imaging technique, which reduces patient discomfort and complications. The perianal region fistula is mainly classified into two types namely, park’s classification and St. James university hospital’s classification. Hence in this literature, we have reviewed the importance of medical imaging modality in interpreting perianal fistula, especially magnetic resonance fistulography, as an accurate preoperative, post-operative, and follow-up medical imaging modality for the perianal fistula’s imaging. The subtraction technique, dynamic contrast imaging, volume imaging, and percutaneous instillation of aqueous jelly into the perianal fistula tract are the latest advances in imaging perianal fistula.