title: Narrow-band imaging with magnification in Barrett's esophagus: validation of a simplified grading system of mucosal morphology patterns against histology.
abstract: OBJECTIVE
  Validation of a simplified classification of mucosal morphology in prediction of histology in Barrett's esophagus using narrow-band imaging with magnification (NBI-Z) and assessing its reproducibility by endoscopists experienced in the use of NBI (NBI-experts) and by endoscopists who were new to NBI (non-NBI-experts).
  
  
  METHODS
  In a prospective cohort study of 109 patients with Barrett's esophagus at a single tertiary referral center, mucosal patterns visualized in Barrett's esophagus on NBI-Z were classified into four easily distinguishable types: A, round pits with regular microvasculature; B, villous/ridge pits with regular microvasculature; C, absent pits with regular microvasculature; D, distorted pits with irregular microvasculature. The NBI-Z grading was compared with the final histopathological diagnosis, and positive (PPV) and negative predictive values (NPV) were calculated. The reproducibility of the grading was then assessed by NBI-expert and non-NBI-expert endoscopists, and interobserver and intraobserver agreement were calculated using kappa statistics.
  
  
  RESULTS
  Per-biopsy analysis: In 903 out of 1021 distinct areas (87.9%) the NBI-Z grading corresponded to the histological diagnosis. Per-patient analysis: The PPV and NPV for type A pattern (columnar mucosa without intestinal metaplasia) were 100% and 97% respectively; for types B and C (intestinal metaplasia) they were 88% and 91% respectively, and for type D (high-grade dysplasia) 81% and 99% respectively. Inter- and intraobserver agreement: The mean kappa values in assessing the various patterns were 0.71 and 0.87 in the non-expert group; 0.78 and 0.91 in the expert group.
  
  
  CONCLUSIONS
  This study has validated a simplified classification of the various morphologic patterns visualized in Barrett's esophagus and confirmed its reproducibility when used by NBI-expert and non-NBI-expert endoscopists.
authors.affiliation: Wolfson Digestive Diseases Centre, Queen's Medical Centre, Nottingham University Hospitals NHS Trust, Nottingham, UK.
authors.forename: R
authors.initials: R
authors.lastname: Singh
authors.forename: G K
authors.initials: GK
authors.lastname: Anagnostopoulos
authors.forename: K
authors.initials: K
authors.lastname: Yao
authors.forename: H
authors.initials: H
authors.lastname: Karageorgiou
authors.forename: P J
authors.initials: PJ
authors.lastname: Fortun
authors.forename: A
authors.initials: A
authors.lastname: Shonde
authors.forename: K
authors.initials: K
authors.lastname: Garsed
authors.forename: P V
authors.initials: PV
authors.lastname: Kaye
authors.forename: C J
authors.initials: CJ
authors.lastname: Hawkey
authors.forename: K
authors.initials: K
authors.lastname: Ragunath
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001471:Barrett Esophagus / Q000145:classification / Q000175:diagnosis / Q000473:pathology*; D001707:Biopsy, Needle; D015331:Cohort Studies; D016001:Confidence Intervals; D004945:Esophagoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000473:pathology; D015588:Observer Variation; D011230:Precancerous Conditions / Q000175:diagnosis; D011336:Probability; D011446:Prospective Studies; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity