A Prospective Study Comparison of Narrow Band Imaging (NBI) Versus Chromoendoscopy with Indigo Carmine (IC) Versus White Light (WL) Colonoscopy in the Detection of Adenomatous Colonic Lesions

Abstract

Background: Colonic early carcinoma and adenomatous precursor flat lesions may not be diagnosed by conventional colonoscopy in up to 24% of cases. Colonic chromoendoscopy with IC or NBI could potentially increase the detection of such lesions, particularly in the right colon. The aim of this study is to evaluate if a larger number of adenomas can be diagnosed by NBI or chromoendoscopy with IC or white light colonoscopy. Methods: An Olympus HD 180 series has been used by two experienced colonoscopists. Exclusion criteria were a history of Inflammatory Bowel Diseases or right colon resection. Each colonic segment was first examined with white light colonoscopy and then followed by chromoscopy with IC 0,4% or NBI. Study outcome was the number of lesions detected with WL compared with NBI and IC. Results: The study groups were well matched for age and sex. A total of 88 patients were enrolled in the study (43 in the NBI group and 45 in the IC group). Seventy two lesions were detected in 52 patients on white light colonoscopy being 39 adenomas, 32 hyperplastic polyps and 1 adenocarcinoma. Compared with WL, NBI detected 9 more lesions in 6 patients, being all lesions flat adenomas (low grade dysplasia) of the right colon and IC found 15 more lesions in 10 patients being 10 of them low grade dysplasia sessile adenomas and 5 hyperplastic flat polyps, all in the right colon. Mean diameter of the lesions diagnosed with NBI and IC were respectively of 3.7 and 4.2 mm. No statistical differences were seen in examination time between NBI (10.6 ± 1.38 min) and IC (11.1 ± 2.32 min). Conclusion: NBI and IC allow easier detection of small/flat colonic lesions compared to WL colonoscopy. No significant differences were found between NBI and IC in polyp detection rate.