Imaging of the bowel wall. Computed tomography and fat density oral-contrast agent in an animal model

In this study, we reassessed the problems encountered in computed tomographic (CT) examinations performed with conventional bowel preparations, and developed a fat density oral contrast in dogs. Conventional high-density agents, water, fat (negative) density, and air were administered using a nasogastric tube to eight dogs (25 separate CT scans). Optimal and consistent identification of the gastrointestinal (GI) tract and mural visualization were achieved with 400 ml of 12.5% to 50% corn oil emulsions administered in four hourly divided doses. Mild diarrhea was observed with the 50% concentration only, but no untoward effect was noted clinically with 25% and 12.5% emulsions. Mixing the negative (fat) density oral contrast with the GI contents produced conditions optimal for high-CT contrast resolution of the GI wall. Standard intravenous administration of iodinated contrast agent enhanced mural visualization and, in conjunction with dynamic scanning, time density curves. This suggests that vascular perfusion could be portrayed. This animal model may be used for the experimental evaluation of a number of GI abnormalities, including ischemic, neoplastic, and inflammatory conditions.