title: Observer variability in gastric neoplasm assessment using the vessel plus surface classification for magnifying endoscopy with narrow band imaging.
abstract: OBJECTIVE
  Recent studies have demonstrated that magnifying endoscopy with narrow band imaging (ME-NBI) facilitates differentiation of early gastric cancer from gastric adenoma using vessel plus surface (VS) classification. This study estimated the interobserver and intraobserver agreement of endoscopists using the Yao VS classification system for the gastric mucosal surface.
  
  
  METHODS
  We retrospectively reviewed patients who underwent endoscopic submucosal dissection or endoscopic mucosal resection, and selected cases in which preoperative ME-NBI was conducted. Before testing endoscopists, a 20-minute training module was given. Static ME-NBI images (n=47 cases) were presented to seven endoscopists (two experts and five trainees) who were asked to assess the images in 20 seconds using the Yao VS classification system. After 2 weeks, the endoscopists were asked to analyze the images again. The κ statistic was calculated for intraobserver and interobserver variability.
  
  
  RESULTS
  The mean κ for intraobserver agreement was 0.69 (experts, 0.74; trainees, 0.64). The mean κ for interobserver agreement was 0.42 (experts, 0.49; trainees, 0.40).
  
  
  CONCLUSIONS
  We obtained reliable results as assessed by observer variability, with only brief training on VS classification. The VS classification appears to provide an objective assessment of ME-NBI for trainees who are not familiar with ME-NBI.
authors.affiliation: Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Chan Hui
authors.initials: CH
authors.lastname: Yoo
authors.affiliation: Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Moo In
authors.initials: MI
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Seun Ja
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Won
authors.initials: W
authors.lastname: Moon
authors.affiliation: Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Hyung Hun
authors.initials: HH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Jun Young
authors.initials: JY
authors.lastname: Song
authors.affiliation: Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Do Hyun
authors.initials: DH
authors.lastname: Kim
keywords: Endoscopy; Neoplasms; Stomach