How we do it: MR enterography

Magnetic resonance enterography (MRE) now plays a central role in diagnosing pediatric inflammatory bowel disease (IBD), and its role in other intestinal pathologies such as scleroderma is gradually expanding. MRE helps distinguish between Crohn disease and ulcerative colitis, defining extent and severity. Standard MRE protocols can be optimized in children and adolescents to be diagnostic and well tolerated, both of which are important with increasing use of serial MRE in pediatric IBD for monitoring treatment response and evaluating complications. MRI is especially suited to this role given its lack of ionizing radiation. MRE compliance can be improved through patient education. Differing from adult MRE, pediatric MRE protocols use weight-based formulas to calculate oral and intravenous contrast media and antispasmodic agent doses, using either hyoscine-N-butylbromide or glucagon. Nausea is more commonly experienced with glucagon; however vomiting occurs in <10% of children with either agent. Standard and advanced sequences applied in adults are also used in children and adolescents. These include static and cinematic balanced steady-state free precession sequences, single-shot T2-weighted sequences, diffusion-weighted imaging and pre- and post-contrast 3-D T1-weighted gradient echo sequences. Magnetization transfer imaging and quantitative assessment of bowel to distinguish inflammation and fibrosis are not yet standard in pediatric MRE, but show promise.