Ryan O'Malley MD, Abstract Co-Author: Nothing to Disclose

Neil Hansen MD, Abstract Co-Author: Nothing to Disclose

Zachary White Washburn MD, Abstract Co-Author: Nothing to Disclose

Mahmoud Mouhamad Al-Hawary MD, Presenter: Nothing to Disclose

Peter Shou-Cheng Liu MD, Abstract Co-Author: Nothing to Disclose

Hero Kamal Hussain MD, Abstract Co-Author: Consultant, Bayer AG

Discuss unique etiologies of complex perianal fistulas that are frequently encountered in practice, but do not fit within the St. James classification. Demonstrate the MRI findings and discuss its unique advantages for depicting these complex fistulas. Discuss how accurate characterization affects management.  

Brief review of anorectal anatomy, St. James classification, and MR findings in perianal fistulas. Discuss specific entities that are prone to complex fistulizing disease and how they do not follow St. James classification scheme: Long-standing inflammatory bowel disease with tracts that can involve any (and often multiple) adjacent structures Fistulas arising from anorectal neoplasms (including lesions presenting solely as fistulizing disease) Fistulas arising at the site of prior anorectal surgical or radiation therapy Sample cases with specific attention to how accurate diagnosis and characterization impacts patient management and quality of life.

MRI is uniquely valuable for assessing complex perianal fistulas that do not fit into traditional classification schemes and can be clinically underestimated. As such, radiologists must be aware of and accurately characterize these entities, which often have a profound impact on patient management and quality of life.

O'Malley, R, Hansen, N, Washburn, Z, Al-Hawary, M, Liu, P, Hussain, H, MR Imaging of Perianal Fistulas: Beyond the St. James Classification.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13025044.html