INCREASED INTESTINAL PERMEABILITY FOR THE ISOSMOLAR CONTRAST-MEDIUM IODIXANOL DURING SMALL-BOWEL ISCHEMIA IN RATS

Background: Intestinal ischaemia may be difficult to recognize in the early stages. Increased urinary recovery of water-soluble contrast medium during an intestinal follow-through has been suggested as a sign of bowel ischaemia. Methods: Urinary excretion of the isosmolar water-soluble X-ray contrast medium iodixanol was measured after instillation via an orogastric tube in 56 rats with occlusion of the mesenteric blood vessels. Results: Mesenteric venous occlusion caused only minor histologic alterations of the mucosa. High-performance liquid chromatography (HPLC) and X-ray fluorescence analysis measured urinary iodixanol concentrations 10 and 13 times higher in the groups with mesenteric arterial occlusion than in controls (p < 0.001), and 3 and 4 times higher than in the group with venous occlusion (p less than or equal to 0.05). Correlation between HPLC and X-ray fluorescence measurements of contrast medium in urine was strong (r = 0.98). Conclusion: Measuring urinary contrast medium levels during intestinal follow-through may aid in distinguishing bowel ischaemia following mesenteric arterial occlusion from mesenteric venous occlusion and from the normal bowel.