Narrow-band imaging optical chromocolonoscopy: Advantages and limitations

Narrow-band imaging (NBI) is an innovative optical technology that modifies the center wavelength and bandwidth of an encloscope's light into narrow-band illumination of 415 +/- 30 nm. NBI markedly improves capillary pattern contrast and is an in vivo method for visualizing microvessel morphological changes in superficial neoplastic lesions. The scientific basis for NBI is that short wavelength light falls within the hemoglobin absorption band, thereby facilitating clearer visualization of vascular structures. Several studies have reported advantages and limitations of NBI colonoscopy in the colorecturn. One difficulty in evaluating results, however, has been nonstandardization of NBI systems (Sequential and nonsequential). Utilization of NBI technology has been increasing worldwide, but accurate pit pattern analysis and sufficient skill in magnifying colonoscopy are basic fundamentals required for proficiency in NBI diagnosis of colorectal lesions. Modern optical technology without proper image interpretation wastes resources, confuses untrained encloscopists and delays interinstitutional validation studies. Training in the principles of "optical image-enhanced encloscopy" is needed to close the gap between technological advancements and their clinical usefulness. Currently available evidence indicates that NBI constitutes an effective and reliable alternative to chromocolonoscopy for in vivo visualization of vascular structures, but further study assessing reproducibility and effectiveness in the colorectum is ongoing at various medical centers. (c) 2008 The WJG Press. All rights reserved.