Common and unusual urogenital Crohn's disease complications: spectrum of cross-sectional imaging findings.

Involvement of the urinary tract and genital organs is not uncommon in patients affected with Crohn's disease (CD). Occurring in both sexes, uro-gynecological complications are often clinically unsuspected because of the dominant intestinal or systemic symptoms. Knowledge of their manifestations and cross-sectional imaging appearances is necessary to recognize and report them, since correct medical or surgical treatment choice with appropriate specialist consultation allows to prevent further complications. Besides uncomplicated urinary tract infections that usually do not require imaging, urolithiasis and pyelonephritis represent the most commonly encountered urinary disorders: although very useful, use of computed tomography (CT) should be avoided whenever possible, to limit lifetime radiation exposure. Hydronephrosis due to ureteral inflammatory entrapment and enterovesical fistulization may result from penetrating CD, and require precise imaging assessment with contrast-enhanced CT to ensure correct surgical planning. Representing the majority of genital complication, ano- and rectovaginal fistulas and abscesses frequently complicate perianal inflammatory CD and are comprehensively investigated with high-resolution perianal MRI acquired with phased-array coils, high-resolution T2-weighted sequences and intravenous contrast. Finally, rare gynecological manifestations including internal genital fistulas, vulvar and male genital involvement are discussed.