In a back-to-back study,49 33 patients underwent HD colonoscopy with NBI followed by CE (0.5% indigo carmine) and 27 patients were randomized to the opposite sequence to assess miss rates of the 2 techniques. The study showed a nonsignificant trend toward a higher miss rate using NBI. In the NBI first group, NBI detected 7 neoplastic lesions in 4 patients during the first pass and CE detected 5 additional lesions in 4 patients during the second pass. In the HD-CE first group, CE detected 5 neoplastic lesions in 4 patients

during selleck chemicals the first pass and NBI detected 3 neoplastic lesions in 1 patient during the second pass. The withdrawal time for CE was significantly longer (26.87 ± 9.89 minutes for CE vs 15.74 ± 5.62 minutes for NBI, P<.01). 49 Preliminary abstract data of a randomized trial comparing HD-NBI with CE (0.1% methylene blue) showed no significant difference in neoplasia detection rates between either modalities (18.5% for HD-NBI and 16.7% for HD-CE, P = .658). 50 At present, CE remains the gold standard for colitis surveillance. Further

studies assessing NBI or other electronic image-enhanced endoscopic methods compared with CE are necessary before any change in recommendations or clinical practice. Autofluorescence imaging (AFI) is a novel imaging technique. AFI is available on the monochrome chip (Lucera, Olympus, Pirfenidone Tokyo, Japan), which has 2 charge-coupled devices for WLE and AFI and can be activated by a push of the button. An ultraviolet filter is placed in front of the light source. All tissues exhibit autofluorescence when excited by ultraviolet (>400 nm) or short visible light (400–550 nm). Autofluorescence is generated by fluorophores, certain biomolecules (collagen, elastin), emitting a longer wavelength than the excitation light. AFI is influenced by several factors, including

tissue architecture (mucosal thickening), light absorption and scattering properties (mainly determined 3-mercaptopyruvate sulfurtransferase by the absorptive capacity of hemoglobin in neoplastic neovascularization), the biochemical content (concentration of fluorophores), and metabolic status of the tissue.52, 53, 54, 55, 56, 57, 58 and 59 Using AFI, neoplastic tissue is visible as a purple lesion on a greenish background fluorescence of normal colonic tissue. AFI has therefore the potential to serve as a red flag technique highlighting even very early minute neoplastic changes in the colonic mucosa. In contrast to NBI, the available data on AFI for colitis surveillance is sparse. In a single prospective randomized crossover trial comparing the neoplasia detection of WLE with that of AFI targeted biopsies, Van den Broek and colleagues16 found a significant higher yield for AFI. In the AFI first group, 10 lesions in 25 patients were detected and subsequent WLE did not detect any additional lesions. However, in the WLE first group, 3 neoplastic lesions were detected in 25 patients, but AFI additionally detected 3 lesions.