title: The learning curve for narrow-band imaging in the diagnosis of precancerous gastric lesions by using Web-based video.
abstract: BACKGROUND
  A simplified narrow-band imaging (NBI) endoscopy classification of gastric precancerous and cancerous lesions was derived and validated in a multicenter study. This classification comes with the need for dissemination through adequate training.
  
  
  OBJECTIVE
  To address the learning curve of this classification by endoscopists with differing expertise and to assess the feasibility of a YouTube-based learning program to disseminate it.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Five centers.
  
  
  METHODS
  Six gastroenterologists (3 trainees, 3 fully trained endoscopists [FTs]).
  
  
  METHODS
  Twenty tests provided through a Web-based program containing 10 randomly ordered NBI videos of gastric mucosa were taken. Feedback was sent 7 days after every test submission.
  
  
  METHODS
  Measures of accuracy of the NBI classification throughout the time.
  
  
  RESULTS
  From the first to the last 50 videos, a learning curve was observed with a 10% increase in global accuracy, for both trainees (from 64% to 74%) and FTs (from 56% to 65%). After 200 videos, sensitivity and specificity of 80% and higher for intestinal metaplasia were observed in half the participants, and a specificity for dysplasia greater than 95%, along with a relevant likelihood ratio for a positive result of 7 to 28 and likelihood ratio for a negative result of 0.21 to 0.82, were achieved by all of the participants. No constant learning curve was observed for the identification of Helicobacter pylori gastritis and sensitivity to dysplasia. The trainees had better results in all of the parameters, except specificity for dysplasia, compared with the FTs. Globally, participants agreed that the program's structure was adequate, except on the feedback, which should have consisted of a more detailed explanation of each answer.
  
  
  CONCLUSIONS
  No formal sample size estimate.
  
  
  CONCLUSIONS
  A Web-based learning program could be used to teach and disseminate classifications in the endoscopy field. In this study, an NBI classification for gastric mucosal features seems to be easily learned for the identification of gastric preneoplastic lesions.
authors.affiliation: Department of Information Sciences and Decision in Health (CIDES) and CINTESIS, Faculty of Medicine of Porto, Porto, Portugal.
authors.forename: Diogo
authors.initials: D
authors.lastname: Dias-Silva
authors.affiliation: Department of Gastroenterology of Oncology Portuguese Institute of Porto, Porto, Portugal; Department of Physiology and Cardiothoracic Surgery, Cardiovascular R&D Unit, Faculty of Medicine, University of Porto, Porto, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Pimentel-Nunes
authors.affiliation: Centro Hospitalar do Alto Ave, Porto, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Magalhães
authors.affiliation: Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Magalhães
authors.affiliation: Department of Gastroenterology of Oncology Portuguese Institute of Porto, Porto, Portugal.
authors.forename: Nuno
authors.initials: N
authors.lastname: Veloso
authors.affiliation: Centro Hospitalar de Lisboa, Lisbon, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Ferreira
authors.affiliation: Faculty of Medicine, University of Coimbra, Coimbra, Portugal; Department of Gastroenterology, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Figueiredo
authors.affiliation: Centro Hospitalar do Alto Ave, Porto, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Moutinho
authors.affiliation: Department of Information Sciences and Decision in Health (CIDES) and CINTESIS, Faculty of Medicine of Porto, Porto, Portugal; Department of Gastroenterology of Oncology Portuguese Institute of Porto, Porto, Portugal.
authors.forename: Mário
authors.initials: M
authors.lastname: Dinis-Ribeiro
mesh_terms: D002983:Clinical Competence; D004502:Education, Medical, Continuing / Q000379:methods*; D016099:Endoscopy, Gastrointestinal / Q000193:education* / Q000379:methods; D004867:Equipment Design; D005240:Feasibility Studies; D006801:Humans; D059032:Learning Curve; D062048:Narrow Band Imaging; D011230:Precancerous Conditions / Q000175:diagnosis*; D011446:Prospective Studies; D012372:ROC Curve; D013270:Stomach / Q000473:pathology*; D013274:Stomach Neoplasms / Q000175:diagnosis*; D014741:Video Recording / Q000295:instrumentation*