VALUE OF BROMINATED FLUOROCARBONS FOR THE RADIOGRAPHIC DIAGNOSIS OF SMALL-BOWEL OBSTRUCTION - COMPARISON WITH OTHER CONTRAST AGENTS IN RATS

OBJECTIVE. The disadvantages of water-soluble gastrointestinal contras t agents include high osmolality, contrast dilution, and severe toxici ty if aspirated. Perfluorocarbons are nontoxic in the lung and periton eal cavity. Because perfluorocarbons are immiscible with water, they h ave no osmotic effect and cannot be diluted. Because these properties offer theoretical advantages over traditional gastrointestinal contras t agents, we compared two perfluorocarbons with barium and ionic and n onionic iodinated contrast material in a rat model of small-bowel obst ruction. MATERIALS AND METHODS. Twelve groups of six rats each had lig ation of the terminal ileum (obstruction model) or of the terminal ile um and mesenteric artery (obstruction with ischemia model). Each rat r eceived 3 ml of barium, meglumine sodium diatrizoate, iohexol, neat pe rfluorooctyl bromide, neat perfluorohexyl bromide, or saline (control animals). Contrast media were given at the recommended concentrations, and their progression was evaluated on serial radiographs by an obser ver who was not aware of the model or the contrast medium given. When one contrast material reached the point of obstruction, all rats in th e group were sacrificed and a final radiograph was obtained. Three rad iologists, who were not aware of the contrast medium given, on two sep arate occasions independently reviewed the radiographs and ranked the contrast agents for their relative radiopacity, mucosal definition, sp eed of transit, gastric retention, and bowel distension. RESULTS. When data from both models were combined, perfluorocarbons were judged on the final image to be the most radiodense, to provide the sharpest muc osal detail, to have the least gastric retention, and to have faster p rogression than barium. Whereas meglumine sodium diatrizoate and iohex ol reached the point of obstruction more rapidly than the perfluorocar bons and barium, they had the greatest gastric retention, caused the m ost bowel distension, and were the least radiopaque. CONCLUSION. Our r esults show that the radiopaque perfluorocarbons are suitable as gastr ointestinal contrast agents and have favorable radiographic characteri stics in this animal model. When these results are combined with the l ow-toxicity profile of perflubron, clinical evaluation of this agent f or the radiographic assessment of bowel obstruction is warranted.