Magnetic Resonance in the study of the small bowel

Magnetic resonance (MR) of the small bowel is a field of application which for many years received little attention, being limited to advanced and selected research centres whose studies had no real clinical impact. Even after the first two publications in 1985, it was not until 1998 and the following years that a decisive improvement in scientific research articles was observed. This was largely due to the need for progressive development of adequate technologies, in particular fast imaging. Although the major technological problems have now been resolved, the optimisation of the study protocol is still under evaluation. In this regard there are two main methodological approaches: 1) "MR follow-through" following administration of an oral contrast medium; 2) "MR enteroclysis", following administration of contrast medium through a nasojejunal tube. Several contrast media are currently available for small bowel study, and they are classified according to signal intensity into positive, negative or biphasic. Biphasic agents are those most commonly used for both MR follow-through and MR enteroclysis. The major clinical indication for a study of the small bowel with MR is the evaluation of chronic inflammatory disease (Crohn's disease). Considerable experience has been obtained over the past years, with the consequent introduction of MR in routine clinical practice in many centres worldwide. Other potential clinical indications, at the moment to be considered work-in-progress, are the evaluation of malabsorption syndromes (and among them, celiac disease) and assessment of neoplastic diseases.