Water-soluble contrast media compared with barium in enteric follow-through. Urinary excretion and radiographic efficacy in rats with intestinal ischemia.

The local effects and radiographic efficacy of four water-soluble contrast media, barium and saline were evaluated in 91 anesthetized rats with a ligature applied to the anterior mesenteric artery and vein via laparotomy. The rats were observed for 8 hours after instillation of 3 mL of test substance via oro-gastric tube. Radiographs were taken after 1, 4 and 8 hours of observation. After 8 hours, the intestines were weighed, a biopsy was done for light microscopy, and blood and urine were sampled for testing. The roentgen contrast media caused dehydration and increased influx of fluid into the small bowel lumen in proportion to their osmolality. They diluted the bowel contents, enhanced their progression and distended the bowel walls. The diagnostic qualities of radiographic films were better using the new, low-osmolal contrast media than using either barium or sodium diatrizoate. The water-soluble contrast media were excreted in the urine, as demonstrated by dense opacification of the urinary bladder on abdominal films, and increased iodine concentrations at x-ray fluorescence analysis of the urine. This may be useful clinically in detecting bowel ischemia.