An experimental endoscopic study on intestinal ischemic lesions in dogs with special reference to fluorescence endoscopy

In order to clarify the pathophysiology of intestinal ischemic lesions and to make a useful method for the prediction of fate of the ischemic bowel, we devised an experimental model to produce the disorder. Microbarium of 0.5 micrometer in diameter was injected into a branch of the superior mesenteric artery of adult mongrel dogs. The severity of the ischemic lesions depended on the amount of microbarium injected, and lesions could be classified into three types; transient, stricturing and gangrenous, similar to clinical cases. Endoscopic examination was performed, accompanied with fluorescence endoscopy. Fluorescein could not be observed in all types soon after microbarium injection. In the transient type, fluorescein was observed after only a few days in an evenly distributed pattern. However in the stricturing type, the appearance of fluorescein was delayed, and an irregular pattern was observed in about 1 week. The submucosal blood flow was measured by hydrogen clearance method. The fluorescence endoscopic findings were nearly compatible with changes of submucosal blood flow. Fluorescence endoscopy is easily performed and appears to be highly useful in the differentiation of these three types of ischemia in the early stages.