Comparison of Mannitol, Water, and Iodine-Based Oral Contrast in the Evaluation of the Bowel by Multi-Detector Computed Tomography

Background and objectives To perform contrast-enhanced computed tomography (CECT) of the abdomen with water, mannitol, or iodinated positive contrast as an oral contrast agent, and compare the distension and enhancement pattern of the bowel. Methods This was a prospective observational study conducted on 90 patients over a period of 12 months who were referred for CECT abdomen. Patients were randomly divided into three groups (30 each) and were given water, mannitol, or positive oral contrast before the CECT study. Quantitative and qualitative analysis of the bowel for distension, mural fold pattern, and enhancement was analyzed at various anatomical levels. A qualitative examination of bowel loops was done in the three groups by using a continuous 4-point scale. Results The mean distension at the duodenum was 1.89 ± 0.33 cm (mean ± SD) with water, 2.28 ± 0.36 cm with mannitol, and 2.01 ± 0.33 cm with positive oral contrast. Overall, maximum luminal distension was seen at the level of the duodenum, followed by the jejunum across all the groups. Bowel characteristics were far superior in the mannitol group compared to water and positive oral contrast at all anatomical levels. Conclusion Small bowel distension was excellent with mannitol, followed by positive oral contrast, and least with water. Mural characteristics and enhancement patterns were better with mannitol as compared with water and with positive oral contrast.