Narrow-band imaging

Narrow-band imaging is an imaging technique for endoscopic diagnostic medical tests, where light of specific blue and green wavelengths is used to enhance the detail of certain aspects of the surface of the mucosa. A special filter is electronically activated by a switch in the endoscope leading to the use of ambient light of wavelengths of 415 nm (blue) and 540 nm (green). Because the peak light absorption of hemoglobin occurs at these wavelengths, blood vessels will appear very dark, allowing for their improved visibility and in the improved identification of other surface structures.{{Cite journal | doi-access = free

In gastrointestinal endoscopy, narrow-band imaging has found use in the identification of Barrett's esophagus, in the identification of pit patterns to classify colorectal polyps and tumours,{{Cite journal | doi-access = free

Alternative methods to improve visualization of the mucosa in endoscopy include chromoendoscopy, confocal microscopy and optical coherence tomography.