title: Validation of a simple classification system for endoscopic diagnosis of small colorectal polyps using narrow-band imaging.
abstract: OBJECTIVE
  Almost all colorectal polyps ≤ 5 mm are benign, yet current practice requires costly pathologic analysis. We aimed to develop and evaluate the validity of a simple narrow-band imaging (NBI)-based classification system for differentiating hyperplastic from adenomatous polyps.
  
  
  METHODS
  The study was conducted in 4 phases: (1) evaluation of accuracy and reliability of histologic prediction by NBI-experienced colonoscopists; (2) development of a classification based on color, vessels, and surface pattern criteria, using a modified Delphi method; (3) validation of the component criteria by people not experienced in endoscopy or NBI analysis (25 medical students, 19 gastroenterology fellows) using 118 high-definition colorectal polyp images of known histology; and (4) validation of the classification system by NBI-trained gastroenterology fellows, using still images. We performed a pilot evaluation during real-time colonoscopy.
  
  
  RESULTS
  We developed a classification system for the endoscopic diagnosis of colorectal polyp histology and established its predictive validity. When all 3 criteria were used, the specificity ranged from 94.9% to 100% and the combined sensitivity ranged from 8.5% to 61.0%. The specificities of the individual criteria were lower although the sensitivities were higher. During real-time colonoscopy, endoscopists made diagnoses with high confidence for 75% of consecutive small colorectal polyps, with 89% accuracy, 98% sensitivity, and 95% negative predictive values.
  
  
  CONCLUSIONS
  We developed and established the validity of an NBI classification system that can be used to diagnose colorectal polyps. In preliminary real-time evaluation, the system allowed endoscopic diagnoses of colorectal polyp histology.
authors.affiliation: Indiana University School of Medicine, Indianapolis, Indiana; The University of Queensland School of Medicine, Brisbane, Australia.
authors.forename: David G
authors.initials: DG
authors.lastname: Hewett
authors.affiliation: Veterans Affairs Palo Alto Health Care System, Palo Alto, California; Stanford University School of Medicine, Stanford, California.
authors.forename: Tonya
authors.initials: T
authors.lastname: Kaltenbach
authors.affiliation: Sano Hospital, Kobe, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Sano
authors.affiliation: Hiroshima University, Hiroshima, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Wolfson Unit for Endoscopy and Imperial College London, St. Marks Hospital, London, United Kingdom.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Saunders
authors.affiliation: Hôpital Edouard-Herriot, Lyon, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Ponchon
authors.affiliation: Veterans Affairs Palo Alto Health Care System, Palo Alto, California; Stanford University School of Medicine, Stanford, California.
authors.forename: Roy
authors.initials: R
authors.lastname: Soetikno
authors.affiliation: Indiana University School of Medicine, Indianapolis, Indiana. Electronic address: drex@iupui.edu.
authors.forename: Douglas K
authors.initials: DK
authors.lastname: Rex
mesh_terms: D018256:Adenomatous Polyps / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D002983:Clinical Competence; D003111:Colonic Polyps / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D003697:Delphi Technique; D003937:Diagnosis, Differential; D005257:Fellowships and Scholarships; D006801:Humans; D006965:Hyperplasia; D015588:Observer Variation; D010865:Pilot Projects; D011127:Polyps / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012002:Rectal Diseases / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013337:Students, Medical; D009626:Terminology as Topic; D014481:United States