The purpose of introducing optical electronics into video endoscopes is to improve the accuracy of diagnosis through image processing and digital technology. Narrow-band imaging (NBI), one of the most recent techniques, involves the use of interference filters to illuminate the target in narrowed red, green and blue (R/G/B) bands of the spectrum. This results in different images at distinct levels of the mucosa and increases the contrast between the epithelial surface and the subjacent vascular network. NBI can be combined with magnifying endoscopy with an optical zoom. The aim of this new technique is to characterize the surface of the distinct types of gastrointestinal epithelia - e. g., intestinal metaplasia in Barrett's esophagus. The technique may also make it possible to demonstrate disorganization of the vascular pattern in inflammatory disorders of the gastrointestinal mucosa and in superficial neoplastic lesions in the esophagus, stomach, and large bowel.