High-definition endoscopy with i-Scan for evaluation of small colon polyps:: the HiSCOPE study

Background Traditional white-light endoscopy cannot reliably distinguish between small ( Objective To compare HDWL endoscopy and HDWL plus i-Scan for the assessment of small colon polyps and to measure performance against the American Society for Gastrointestinal Endoscopy (ASGE) thresholds for assessment of diminutive colon polyps. Design Prospective cohort study. Setting Single academic hospital. Patients Patients undergoing bowel cancer screening colonoscopy. Intervention In vivo assessment of all polyps  Main Outcome Measurements The primary outcome measure was overall diagnostic accuracy of in vivo assessment of colon polyps  Results A total of 209 polyps in 84 patients were included. There were no significant differences between HDWL endoscopy and i-Scan in characterization of polyps  P  = 1.00; sensitivity 95.5% vs 97.0%; P  = .50; specificity 89.3% vs 90.7%; P  = 1.00). The negative predictive value for adenomatous histology of diminutive rectosigmoid polyps was 100% with both HDWL endoscopy and i-Scan. U.K. and U.S. polyp surveillance intervals were predicted with 95.2% accuracy with HDWL endoscopy and 97.2% accuracy with i-Scan. Limitations Single-center study. Conclusion HDWL endoscopy may be as accurate as HDWL with i-Scan image enhancement for the in vivo characterization of small colon polyps. Both modalities fulfil the ASGE performance thresholds for the assessment of diminutive colon polyps. (Clinical trial registration number: NCT01761279.)