Fistula in ano, commonly encountered conditions, is an abnormal tract communicating between the anal canal and perianal skin.  These tracts are filled with granulation tissue and are surrounded by thick fibrous tissue. 90 percent of fistulas are of cryptoglandular origin with the internal orifice in the anal canal, at the level of the anal gland crypt. In 10% of the cases, fistulae are a manifestation of Crohn’s disease, tuberculosis, fungal infection, tumor, or trauma, which are usually complex in nature. It is a chronic and potentially debilitating problem due to repeated pus discharge from external openings in addition to pain, itching, and perianal swelling. Rarely, there can be systemic spread of these infections, incapacitating the individual. In Ayurveda, disease with similar clinical features is described called as bhagandara and this disease is considered as one the grave disease among mentioned eight grave diseases.

Most of these anal fistulae are easy to diagnose with history taking and physical examination. In 48% of cases, but as surgery is the mainstay for treatment of fistula-in-ano. Inadequate excision leads to frequent recurrences and over-excision may lead to sphincter incontinence.  Therefore, accurate and detailed preoperative assessment plays a vital role in the treatment planning and outcome. There are three main radiological imaging techniques in perianal fistulas which are essential in the evaluation of the fistula extent, type of tissues involved and presence of additional inflammatory or purulent foci, location of external and internal openings of the fistula, and the course of the main canal and potential additional branches. They include: contrast fistulography, endorectal ultrasonography and magnetic resonance imaging 

Fistulography is a good diagnostic method for detecting the internal opening in a fistula-in-ano, and it is still used in spite of the introduction of newer, more informative methods.  It is simple and affordable procedure which can be done in an outpatient clinic.  In this technique, the external opening is cannulated with a small-caliber tube and contrast material is injected under minimal pressure while films are taken in several projections. X-ray fistulography may be useful in identifying unsuspected pathology, planning surgical management, and demonstrating anatomic relationships, the sensitivity of that method, according to different authors, ranges from 24% to 50%, however this technique gradually lost its diagnostic value due to non-visualisation of additional branches and anorectal sphincter complex. Now days MR imaging is choice among imaging techniques due to its higher specificity and sensitivity in detection of fistulous tract but its availability in remote areas making difficult for anorectal surgeon to adopt it and overall MR fistulography  highly expensive as compared to other imaging technique.