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

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 (κ 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 .)