Zooming in on Barrett oesophagus using narrow-band imaging: an international observer agreement study

BACKGROUND: Several classifications of mucosal morphology have been proposed in Barrett oesophagus using narrow-band imaging (NBI). We evaluated a simplified classification in which only the regularity of mucosal and vascular patterns were evaluated.

AIM: To assess the inter and intraobserver agreement and the correlation with histology of a simplified NBI classification of mucosal morphology in Barrett oesophagus combining the experience of two referral centres.

METHODS: Two hundred NBI images [57 high-grade intraepithelial neoplasia (HGIN)/early cancer (EC)] were evaluated twice by four NBI-experienced and four nonexperienced endoscopists in the field of NBI. Endoscopists assessed each image for: quality, suspicion for dysplasia, and regularity of mucosal and vascular patterns. Observer agreement was assessed using kappa statistics.

RESULTS: Overall interobserver agreement for the items evaluated was 'moderate' and varied between 0.42 and 0.44. Overall intraobserver agreement was 'moderate' to 'substantial' (kappa 0.60-0.62). There were no significant differences in agreement between expert and nonexpert endoscopists. Endoscopist correctly identified 71% of the images containing HGIN/EC. Of the areas without HGIN/EC, 68% were correctly identified as not suspicious. Again, there were no significant differences between experts and nonexperts.

CONCLUSION: Our proposed, simplified classification for Barrett mucosal morphology has a moderate interobserver and a moderate to substantial intraobserver agreement. The lack of differences in agreements between expert and nonexpert endoscopists suggests a short learning curve. The disappointing rate for correctly indentifying HGIN/EC, questions, however, whether detailed inspection of Barrett oesophagus with NBI can replace histological sampling.