Opacification of the small bowel with intravenously administered contrast medium.

Abstract

This report will describe the opacification of the small bowel in the cat following the intravenous administration of high doses of certain urographic contrast media and the conditions under which a similar opacification of the small bowel may occur clinically. Our interest in visualization of the small bowel by the intravenous route was stimulated by experiments designed to demonstrate the pancreas with an intravenous contrast medium. Ingraham and Visscher (1) found that acid dyes containing the chromagen in the anion are selectively excreted by the pancreas. Their work suggested that analogous contrast media, as sodium diatrizoate2 with the covalently bound iodine in the anion, might be similarly excreted by the pancreas. High doses of sodium diatrizoate (1 to 3 gm./kg.) were injected intravenously in cats, followed by serial x-ray examinations. Although the pancreas failed to opacify, the small bowel was visualized in addition to the anticipated visualization of the urinary tract and gallbladder. A series of experiments were then performed to investigate further the demonstration of the small bowel under these conditions. Experimental Method and Results A group of cats were given high doses of sodium diatrizoate (1 to 3 gm./kg.) intravenously under Nembutal anesthesia. Serial films were made of the abdomen at fifteen-minute intervals during the first hour and then every hour for six to eight hours. The urinary tracts filled immediately (Fig. 1, A), the visualization persisting for two to three hours. Opacification of the small bowel appeared about thirty minutes after the injection (Fig. 1, B and C) and persisted for two to four hours. It was most evident in the midportion, due predominantly to contrast medium within the lumen, although the bowel wall was also faintly opacified. At the end of about four hours, the small bowel was empty of the medium, and the colon was irregularly outlined by contrast material within fecal masses (Fig. 1, D). The gallbladder usually was visualized at three hours and remained opacified beyond eight hours. The cats survived these experiments without complications. To prove that the opacification of the small bowel is due to contrast medium excreted by the bowel wall, ligation was performed at three sites: (a) the duodenum distal to the papilla of Vater, to exclude excretion of the contrast medium from the biliary tract and pancreas; (b) the midsmall bowel; (c) the terminal ileum (Fig. 2, A).