Usefulness of Non-magnifying Narrow Band Imaging in EVIS EXERA III Video Systems and High-Definition Endoscopes to Diagnose Dysplasia in Barrett’s Esophagus Using the Barrett International NBI Group (BING) Classification

Narrow band imaging (NBI) allows identification of abnormal areas of Barrett’s esophagus (BE) and could facilitate targeted biopsies. We evaluated the diagnostic accuracy for dysplasia prediction using non-magnifying NBI in Evis Exera III processors and high-definition endoscopes using the Barrett International NBI Group (BING) classification, as well as inter/intraobserver agreement for dysplasia prediction and mucosal/vascular patterns. Eight observers (4 staff endoscopists and 4 trainee endoscopists) evaluated 100 images selected from an anonymized bank of 470 photographs using the BING classification. Observers were to assign their individual assessment of the mucosal and vascular pattern, and prediction for dysplasia. Accuracy for dysplasia prediction and intra/interobserver agreement was calculated. Dysplasia prediction had an accuracy of 81.1%, sensitivity of 48.4%, and a specificity of 91%. Positive predictive value and negative predictive value (NPV) were 61.4 and 85.5%, respectively. Dysplasia prediction done with a high degree of confidence (vs. low degree of confidence) had better diagnostic accuracy (85.8 vs. 70.7%). Interobserver concordance for dysplasia was weak: Κ = 0.40. Agreement for mucosal and vascular patterns was 0.39 and 0.30, respectively. Intraobserver concordance (assessed 6 months after initial test) for mucosal pattern, vascular pattern, and dysplasia prediction was moderate: Κ = 0.56, Κ = 0.47 and Κ = 0.60, respectively. Our results showed that NBI had a significant accuracy in BE assessment for dysplasia prediction, high specificity (>90%), and NPV (>85%), with suboptimal sensitivity. NBI could be a useful additional tool for BE inspection and targeted biopsies, but cannot avoid the need for biopsies following the Seattle protocol.