Paediatric magnetic resonance enterography in inflammatory bowel disease

Paediatric magnetic resonance enterography (MRE) has been increasingly employed in the evaluation of inflammatory bowel disease (IBD) in the past decade. This is in parallel with a global rise in paediatric-onset IBD, greater recognition of the hazards of ionizing radiation, especially in children, and improved treatment options. MRE is now the reference standard for assessing the small bowel in suspected or proven paediatric IBD, and is central to the diagnosis of Crohn's disease (CD), helping distinguish it from ulcerative colitis. This review will discuss the standard and advanced techniques applied in paediatric MRE to define the presence, extent and severity of intestinal IBD, and increasingly colonic and perianal disease. Its role in demonstrating enteric and extra-enteric disease and characterizing this as active inflammation and/or damage will be explored, including the utility of cinematic, diffusion weighted and magnetization transfer imaging. While MRE is increasingly used to guide medical versus surgical management, considerable overlap exists between conventional MRE imaging features for inflammation and damage, as reflected pathologically, which is driving ongoing research. Paediatric MRE-based scoring systems for CD are currently under development that will further consolidate the role of MRE in paediatric IBD, reinforced by implementation of standardized analysis, interpretation and reporting. As an imaging biomarker, MRE performs well when referenced against endoscopy and clinical biomarkers for evidence of mucosal healing, the current treatment goal. MRE is anticipated to have even greater impact as an imaging biomarker through demonstration of transmural disease and healing, not amenable to endoscopic assessment.