Endoscopic assessment and grading of Barrett's esophagus using magnification endoscopy and narrow-band imaging: accuracy and interobserver agreement of different classification systems

Background: Three different classification systems for the evaluation of Barrett's esophagus (BE) using magnification endoscopy (ME) and narrow-band imaging (NBI) have been proposed. Until now, no comparative and external evaluation of these systems in a clinical-like situation has been performed. Objective: To compare and validate these 3 classification systems. Design: Prospective validation study. Setting: Tertiary-care referral center. Nine endoscopists with different levels of expertise from Europe and Japan participated as assessors. Patients: Thirty-two patients with long-segment BE. Interventions: From a group of 209 standardized prospective recordings collected on BE by using …