Oral contrast agents for small bowel MRI: comparison of different additives to optimize bowel distension

The purpose of this study was to compare two osmotic carbohydrate sugar alcohols (mannitol 2.5% and sorbitol 2.5%, 2.0%, and 1.5% watery solutions) in combination with 0.2% locust bean gum (LBG) for small bowel distension for MR imaging. Small bowel distension was quantified on coronal 2D TrueFISP images by measuring the diameters of 16 small bowel loops in each of 12 healthy subjects (age range 31-55 years). Additionally, the grade of small bowel distension was rated qualitatively. Patient acceptance concerning nausea, vomiting, flatulence, and diarrhea was noted for each solution, and all results were compared by a Wilcoxon test or t test, respectively. The ingestion of water combined with LBG and either 2.5% mannitol or 2.0% sorbitol showed the best distension of the small bowel. The lowest side effect rate was observed following ingestion of sorbitol in a concentration of 2.0 and 1.5%. Based on these data, we recommend a combination of LBG and 2% sorbitol use for optimal bowel distension and minimal side effects resulting in enhanced patient acceptance.