Magnetic resonance imaging in the management of anal fistula and anorectal sepsis.

Complex perianal disease may be extremely debilitating for the patient with significant impingement on quality of life. The accurate identification of anatomical areas of involvement and subsequent appropriate management is crucial to achieving a successful outcome when treating anorectal sepsis and anal fistulae. Magnetic resonance imaging (MRI) has become a powerful tool in the evaluation of anal anatomy. In patients with complex disease MRI is an important adjunct in delineating disease location and extent, its relationship to sphincter muscles, and in planning management. MRI also plays an important role in evaluating the response to medical and surgical therapies.