Imaging Crohn’s disease: comparing the benefits of CT and MR enterography

What is enterography? It is worth taking a moment to explain the term ‘enterography’, as it is often misunderstood. Enterography is an examination optimized for evaluation of the small bowel. As such, oral contrast is administered, which is designed both to be low in attenuation/signal compared with the enhancing mucosa and to distend the small bowel. The contrast should be low in attenuation/ signal compared with the mucosa to permit detection of subtle hyperenhancement, which is among the earliest radiological signs of IBD [4]. Perhaps more importantly, adequate bowel distension permits confident differentiation of small bowel thickening and stricture from loops that are simply collapsed [5]. Various agents and concoctions have been tried, but many institutions use VoLumen (Bracco, Milan, Italy), which we use for both CTE and MRE. Unfortunately, the small bowel distension achieved with VoLumen is variable depending on the GI transit time and, to a large degree, on the patient’s willingness to drink it while suffering from a possible flare of IBD. However, it is currently the best available option in lieu of CT or MR enteroclysis, which is an invasive technique requiring naso-duodenal intubation to instill oral contrast via an electric pump.