title: Analysis of interobserver variability for endomicroscopy of the gastrointestinal tract.
abstract: BACKGROUND
  Endomicroscopy allows in vivo microscopic investigation of enteral mucosa during endoscopic examinations. The aim of this study was to determine interobserver variability in the evaluation of endomicroscopic pictures of several organs by groups of investigators composed of confocal experts, pathologists and students.
  
  
  METHODS
  Twenty-five selected representative endomicroscopic pictures of the colon, stomach and oesophagus (total number, 75) were evaluated based on tissue, inflammatory and neoplastic changes (secondary endpoints). The endomicroscopic presence of neoplastic features was the primary endpoint and correlated with the final histological diagnosis.
  
  
  RESULTS
  The kappa values for experts examining colon, stomach, and oesophagus pictures were 0.80, 0.91, and 0.488, respectively; for students 0.74, 0.684, and 0.527 and for pathologists 0.749, 0.633, and 0.346, respectively. Neoplasia was accurately diagnosed in 67-97% of patients with no significant differences between the 3 groups. Tissue differentiation was determined best by pathologists, whereas the degree of inflammation was better diagnosed by experts and students. In all 3 groups the diagnosis of oesophageal diseases was the most difficult.
  
  
  CONCLUSIONS
  Endomicroscopic images can be interpreted with high concordance. In our study, the diagnostic reliability was not different between students, endomicroscopic experts, and pathologists. Thus, endomicroscopy could be an additional and reliable imaging modality for diagnosing mucosal neoplasia of the gut.
authors.affiliation: St. Mary's Hospital, Department of Medicine, Frankfurt, Germany; Medical Department, Johannes Gutenberg University of Mainz, Germany. Electronic address: a.hoffman@katharina-kasper.de.
authors.forename: Arthur
authors.initials: A
authors.lastname: Hoffman
authors.affiliation: St. Mary's Hospital, Department of Medicine, Frankfurt, Germany; Medical Department, Johannes Gutenberg University of Mainz, Germany.
authors.forename: Johannes Wilhelm
authors.initials: JW
authors.lastname: Rey
authors.affiliation: Medical Department, Johannes Gutenberg University of Mainz, Germany.
authors.forename: Lena
authors.initials: L
authors.lastname: Mueller
authors.affiliation: Institute of Pathology, Johannes Gutenberg University Mainz, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Hansen
authors.affiliation: Medical Department, Johannes Gutenberg University of Mainz, Germany; Medical Department, University of Tübingen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Goetz
authors.affiliation: Max Planck Institute, Cologne, Germany.
authors.forename: Achim
authors.initials: A
authors.lastname: Tresch
authors.affiliation: Medical Department, Johannes Gutenberg University of Mainz, Germany.
authors.forename: Peter Robert
authors.initials: PR
authors.lastname: Galle
authors.affiliation: St. Mary's Hospital, Department of Medicine, Frankfurt, Germany; Medical Department, Johannes Gutenberg University of Mainz, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Kiesslich
mesh_terms: D003106:Colon / Q000473:pathology; D003110:Colonic Neoplasms / Q000473:pathology*; D016145:Endoscopy, Digestive System / Q000706:statistics & numerical data*; D004938:Esophageal Neoplasms / Q000473:pathology*; D004947:Esophagus / Q000473:pathology; D006801:Humans; D008853:Microscopy / Q000706:statistics & numerical data*; D018613:Microscopy, Confocal / Q000706:statistics & numerical data; D015588:Observer Variation; D010336:Pathology / Q000706:statistics & numerical data*; D013270:Stomach / Q000473:pathology; D013274:Stomach Neoplasms / Q000473:pathology*
keywords: Colon cancer; Endomicroscopy; Experts; Inter observer variability; Pathologists; Students