 In the UGI endoscopy study that compared NBI with WLE in the general population, it was found that most focal lesions were due to IM and that after age 50 years, the prevalence rate of IM was 3612. In this study, WLE detected IM in 4.4 of cases, whereas NBI detected IM in 16.2 of cases. We arbitrarily assumed that HD WLE increase the detection rate of IM to 10, while keeping the IM det4ection rate by NBI to 16.2. We determine our sample size to detect a 6.2 difference with a power of 80 and a two sided type 1 error of 0.05. A total of 464 patients will be required. 