A recent single arm prospective cohort study suggested that high definition colonoscopy with narrow band imaging is an acceptable strategy to diagnose polyp histology and determine future surveillance intervals. Endoscopic proficiency in macroscopic features to differentiate polyp histology can be attained in a relatively short time period. A new high definition colonoscope with close focus narrow band imaging features may further improve diagnostic accuracy for polyp differentiation, and can replace formal pathologic assessment in cases of high diagnostic confidence.~Primary Aim: Compare the diagnostic accuracy of high definition narrow band imaging colonoscopy with and without close focus features for the macroscopic differentiation of neoplastic and non-neoplastic colorectal lesions using histopathologic diagnosis as the reference standard.~Secondary Aims: Compare diagnostic characteristics of the colonoscopes, measure concordance of high confidence and accuracy, compare accuracy of predicted versus actual surveillance interval recommendations, perform a cost-effective analysis of endoscopic versus pathologic diagnoses, and measure complications.
The investigators hypothesize that high definition colonoscopy with close focus narrow band imaging features has a high diagnostic accuracy for colorectal polyp histology, and can replace formal pathologic assessment in cases of high diagnostic confidence.