CHROMOENDOSCOPY IN THE UPPER GASTROINTESTINAL TRACT (WITH VIDEOS)

Abstract

Indigo carmine and Lugol are frequently used as dyes for chromoendoscopy in the upper gastrointestinal tract. Indigo carmine is used in portions of the digestive tract that are covered with columnar epithelium such as the stomach and duodenum. It does not chemically react with the cell surface or intracellular substances, and makes it easier to recognize minute changes by highlighting the unevenness of the mucosal surface. This is the so-called contrast method. Therefore, it is essential that the mucus on the surface is thoroughly flushed before indigo carmine is carefully sprayed. Lugol is a liquid containing iodine, glycerin, etc. The iodine-starch reaction occurs between iodine and glycogen granules contained in normal esophageal squamous epithelium, and the normal epithelium turns brown. However, in patients with esophageal cancer, the epithelium does not contain glycogen granules and does not turn brown upon Lugol spraying. The staining method using Lugol facilitates recognition of esophageal cancer due to the presence or absence of glycogen granules. In the case of multiple Lugol-voiding lesions, the so-called pink color sign in which the cancerous part turns pink within a few minutes after application of Lugol, is useful for distinguishing between cancerous and non-cancerous tissues.