Magnetic resonance imaging of perianal and perineal crohn disease in children and adolescents.

Noninvasive, nonionizing, multiparametric magnetic resonance (MR) imaging of the pelvis using a field strength of 3 T now provides a comprehensive assessment of perineal involvement in pediatric Crohn disease. MR imaging accurately evaluates inflammatory disease activity, and allows determination of the number and course of fistula tracts as well as their relationships to vital perianal structures, including the external anal sphincter, helping to guide surgical management and improve outcomes. This article provides an up-to-date review of perineal MR imaging findings of Crohn disease in the pediatric population, including fistulous disease, abscesses, and skin manifestations. Imaging technique is also discussed.