Contraste intestinal en resonancia magnética

Abstract

Magnetic resonance enterography is primarily indicated for inflammatory bowel diseases. MRI of the gastrointestinal tract has become feasible due to the emergence of ultrafast sequences with higher spatial resolution and phased-array coils, enabling wider fields of vision. However, to ensure that the examination is of sufficient quality, the patient should be given an oral or rectal contrast preparation to distend the lumen and improve intestinal wall definition. These contrast agents are defined as positive, negative or biphasic, according to the signal intensity they induce in the intestinal lumen. The contrast agents most commonly used are biphasic and these appear hyperintense on T2 and hypointense on T1. A ‘black’ intestinal lumen has to be achieved on contrast-enhanced 3D T1-weighted sequences for mucosal assessment and parietal enhancement. While biphasic agents, such as PEG and mannitol, are more cost-effective and accessible, they are relatively unpleasant for patients. Negative agents are preferred, but are not routinely available. The purpose of this article is to review the different types of contrast agent that can be used in gastrointestinal MRI and that are mentioned in the literature, analysing the effects they generate on the image, their possible indications and limitations.