Imaging of anal fistulas

There are many radiological imaging techniques for perianal fistulas; the choice of modality may depend on several factors other than simply diagnostic accuracy. Equipment availability and financial constraints vary between healthcare systems. Inexperienced clinical assessment may miss secondary extensions; the resulting recurrence is expensive and upsetting for patients. Fistulography no longer has a role in fistulas arising from the anus itself, but it may be useful in identifying extra-sphincteric tracts arising from abdominal organs, such as appendix, terminal ileum, and sigmoid colon. CT has a limited role acutely but otherwise there are better methods. In the right hands, Endo-anal ultrasonography is still more accurate than clinical examination alone, but requires considerable skill in interpretation, is operator dependent, and may not be suitable for all patients. magnetic resonance imaging scans are the gold standard for fistula.