Endoscopy

Abstract

Endoscopy is an imaging method that is used to visualize the interior of human organs. The widest application of endoscopy is in the gastrointestinal tract. Specialized instruments have been developed to image specific gastrointestinal organs. Gastroscopes, which are passed through the mouth, are used to examine the esophagus, the stomach, and the duodenum. Enteroscopes, also through the mouth, are specially designed to examine the small intestine. Colonoscopes, passed through the anal orifice, are used to examine the lower gastrointestinal tract. There are two major classes of instruments, fiber‐optic endoscopes that consisting of a bundle of coaxial fiber‐optic bundles or electronic endoscopes that rely on a charge coupled device. The electronic endoscope consists of a charge‐coupled device that transmits an electronic signal resulting in an image that is visualized on a television monitor. Modern endoscopes, whether electronic or fiber‐optic contain three systems: ( 1 ) a mechanical system used to deflect the endoscope tip, ( 2 ) a system of air/water and biopsy/suction channels with controls. Insufflation of air is important to distend the walls of the organ being studied. Suction capabilities allow the aspiration of contents from the gastrointestinal tract for examination. In other cases, fluid in the gastrointestinal tract obscures the view and suction allows the fluid to be aspirated away. ( 3 ) The imaging system which may be fiber‐optic or electronic is used to visualize tissue. The most frequent reasons for which endoscopy is performed and the organs that are visualized are listed. Examples of endoscopic images are given.