Narrow‐band imaging in the colon: Limitations and potentials

Abstract

Narrow-band imaging (NBI) is a new endoscopic technology that highlights surface structures and superficial mucosal capillaries during colonoscopy at a single push of a button. NBI has a high sensitivity and specificity for differentiating neoplastic and nonneoplastic polyps by means of mucosal and capillary patterns. It is also useful in determining the invasion depth of early colorectal cancers and evaluating free margins after endoscopic resection. However, it has not been shown to improve the adenoma detection rate compared with white-light endoscopy. Although narrow-band imaging is now available commercially, its role in routine clinical practice during colonoscopy is not well defined. The difficulties in interpreting results partly relate to different NBI nomenclatures used in classifying colonic adenomas and their lack of standardization. Future research should focus on establishing a reliable NBI nomenclature for capillary patterns, defining the learning curve and interobserver variation, and validating the effectiveness of NBI in routine colonoscopy.

Comparison of detection and miss rates of narrow band imaging, flexible spectral imaging chromoendoscopy and white light at screening colonoscopy: a randomised controlled back-to-back study

“…First, the brightness of the virtual image is still not sufficient to ensure a good overview in a large luminal diameter of colon even if these systems are used with HD technology 5 6. Of particular interest in the current study were the minor differences in favour of WL for experts, which indicates that WL colour is easier to assess for colonoscopists with experience than the somewhat more sophisticated virtual CE, but this remains speculative and warrants further investigation.…”

“…Of particular interest in the current study were the minor differences in favour of WL for experts, which indicates that WL colour is easier to assess for colonoscopists with experience than the somewhat more sophisticated virtual CE, but this remains speculative and warrants further investigation. Moreover, intestinal fluid such as bile appears reddish in colour, similar to blood, and obstructs the view to a greater extent than WL 5 6. Therefore, even minor failings in bowel preparation make comprehensive and meticulous detection difficult when using NBI or FICE.…”

Endoscopic Molecular Imaging of Cancer

“…Switching back and forth between WLE and NBI is relatively easy. NBI utilizes narrow band filters: light (essentially blue) with a short wavelength, which penetrates the mucosa superficially and is absorbed by hemoglobin, which highlights mucosal surface patterns and micro vascular detail [16]. Owing to the density and shape of microvessels that change in neoplasia, NBI may potentially aid in the diagnosis of neoplasia simply by recognizing tumor-associated micro vasculature [17].…”

Equipment-Based Image-Enhanced Endoscopy for Differentiating Colorectal Polyps

“…According to the surface color, capillary shape, and surface structure of the colorectal mucosa, several NBI classifications have been proposed 11,12. Based on the classification type, NBI could be helpful in the differentiation between colorectal adenomas and hyperplastic polyps.…”