Magnetic Resonance Enterography in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are chronic disorders of the gastrointestinal tract with a remitting-relapsing disease pattern. Ulcerative colitis (UC) and Crohn's disease (CD) represent the two main forms of IBD.

In CD inflammation affects various parts of the bowel, separated by unchanged intestinal segments, while in ulcerative colitis enteric involvement is continuous, extending from the rectum throughout the colon. Additionally, in Crohn's disease the inflammatory process spreads through all layers of the intestinal wall, while in UC only the mucosa and sub mucosa are affected.

Imaging findings, endoscopic studies and histological data together with clinical assessment, can be used to help distinguish these two forms, determine prognosis, assess disease activity and to inform treatment decision-making.

A "treat-to-target" strategy with close monitoring of intestinal inflammation is recommended in inflammatory bowel disease (IBD). Ileocolonoscopy (CS) remains the gold-standard for assessing disease activity in IBD but is a relatively invasive procedure and is impossible to repeat in the context of tight monitoring strategies.

MRE is preferred over computed tomography enterography by most radiologists and gastroenterologists because of the potential for differentiating active inflammation from fibrotic strictures, and due to the lack of exposure to ionizing radiation. This is especially true in children, as the onset of IBD in childhood is a known risk factor for high cumulative exposure to ionizing radiation from imaging.

MRE furthermore provides a transmural study of bowel loops (oedema, wall thickening, and enhancement post contrast). These features make MRE ideally suitable to the IBD population.