Narrow-band imaging versus I-Scan for the real-time histological prediction of diminutive colonic polyps: a prospective comparative study by using the simple unified endoscopic classification

Abstract

Background: Digital chromoendoscopy (DCE) has the potential for the in vivo optical diagnosis of colon polyps. However, no comparison of different DCE technologies currently exists. Objective: To compare the diagnostic efficacies of narrow-band imaging (NBI) with those of I-Scan for the real-time histological prediction of diminutive colonic polyps (DCPs) (<= 5 mm) by using the simple unified endoscopic classification. Design: Prospective cohort study. Setting: Academic hospital. Patients: In total, 296 DCPs from 142 patients undergoing screening or surveillance colonoscopy were assessed. Interventions: All DCPs detected during withdrawal were evaluated for the surface details by using high-definition white-light colonoscopy, and thereafter by using DCE (NBI or I-Scan) without optical magnification. The histology of all polyps was predicted in real-time and confirmed through the evaluation of biopsy or polypectomy specimens. Main Outcome Measurements: Diagnostic efficacies of NBI and I-Scan. Results: NBI and I-Scan displayed a significantly higher sensitivity and improved accuracy compared with high-definition white-light colonoscopy for the prediction of adenomas (P < .05). No significant differences were evident between the NBI and I-Scan (sensitivity, 88.8% vs 94.6%; specificity, 86.8% vs 86.4%; accuracy, 87.8% vs 90.7%, respectively; P > .05). Additionally, substantial levels of intra- and interobserver agreement between the NBI and I-Scan were measured (kappa values >0.7). Limitations: No randomized or crossover design. Conclusions: NBI and I-Scan displayed a similar efficacy for the real-time histological prediction of DCPs. The simple unified endoscopic classification can be used for the interpretation of DCE, regardless of the type of technology. (Clinical trial registration number: NCT1133041.) (Gastrointest Endosc 2011;74:603-9.)