Cathartic preparation should be performed in order to clean residual stool from bowel loops from to allow a better visualization of mucosal features and an easier luminal distention as well. This type of preparation usually implies a fiber restricted diet and intake of water solution with laxative effect few days before the exam, and abstaining from food intake starting from six hours prior to the study. Use of enteric contrast media is recommended, aiming to distend small bowel loops, and it is administered orally at regular intervals approximately 40 minutes before the study. The type of endo-luminal contrast media varies among negative contrast media, consisting of superparamagnetic agents that evoke low signal both in T1 and T2 weighted images, positive contrast media, represented by paramagnetic agents, that produce high signal on both sequences, or biphasic contrast media, that gives high signal intensity in T2 and low intensity in T1. This latter, that consists of water,
methyl cellulose or
polyethylene glycol, is the most used, because of the wide availability, low cost, good patient compliance, and good taste. Water enema may be administered as well in order to distend bowel loop (MR-colonography). Intravenous contrast media increases diagnostic capability of enterography MRI. Although it is better tolerated than iodinated contrast media used for CT-scan, the use of gadolinium-based
contrast agent should always be preceded by kidney function assessment, in order to reduce the risk of
nephrogenic systemic fibrosis, and prophylactic protocol in case of previous allergic reactions.
Antispasmodic agents may be used to reduce the motion artifacts due to
peristalsis. == Protocol ==