Intestinal distension in patients with Crohn's disease studied by CT and MRI: techniques and review of the literature.

MRI and CT are routinely performed in patients with Crohn's disease and allow a panoramic view of the abdominal region, permitting to identify intestinal disease, extraintestinal manifestations, and vascular alteration surrounding the bowel wall. Considering that most errors are related to an insufficient distension of the bowel, the requisite for an adequate MRI or CT study of the intestine is the correct bowel distension in order to have the visualization of the entire bowel. For these reasons, CT and MRI are performed after administration of a contrast medium by mouth (MR-enterography; CT-enterography) or by nasojenunal tube (MR-enteroclysis; CT-enteroclysis). The method of administration of the contrast medium affects the degree of distension of the intestinal loops. In particular, not all small bowel loops are equally distended after administration of the contrast agents by mouth, being the ileum usually better distended than the jejunum. This problem could be solved by using MR-enteroclysis and CT-enteroclysis. In these techniques, contrast medium is administered through the nasojejunal tube, and a better small bowel distension is usually obtained. Even if the study of small bowel disease is the most common indication of MR-enterography or MR-enteroclysis and CT-enterography or CT-enteroclysis, these techniques occasionally may be focused on colon examination. Additionally, water enema may be performed at the end of the MR-enterography (hydro-MRI) to reach optimal colon-rectum distension. In this paper, the authors review the techniques of intestinal distension described in the literature, using some CT and MR examples.