Barrettʼs Esophagus Lesion Identification With Volumetric Laser Endomicroscopy: Interobserver Agreement Between Expert and Novice Users

Abstract

Introduction: Volumetric Laser Endomicroscopy (VLE) is used to detect Barrett's esophagus (BE) dysplasia. VLE features of glandular atypia, increased surface signal intensity, and lack of layering are associated with BE dysplasia. Experienced VLE users show high interobserver agreement in identifying a region of interest (ROI) containing these features. The accuracy of novice users in dysplastic ROI identification is unknown. The study aim was to determine the interobserver agreement between novice and experienced VLE users for dysplastic ROI identification. Methods: 18 VLE scans (12 high-grade dysplasia; 6 intramucosal adenocarcinoma) from a US based multicenter registry were selected. To optimize interpretation, scans were divided into videos corresponding to 1 cm of circumferential BE, representing ˜200 cross-sectional images. Each video was divided into four quadrants. For each quadrant, reviewers were asked to select the timeframe with the most representative features of dysplasia. If a quadrant contained no features of dysplasia, reviewers were asked to rate it as non-dysplastic BE. Expert VLE raters had experience reviewing >50 VLE scans. Novice VLE raters were endoscopists with no VLE experience who were presented a 20 minute tutorial of images/videos on VLE features of BE dysplasia. High agreement among VLE reviewers in each group (experts vs. novice) was defined by ≥75% agreement on the quadrant diagnosis (dysplastic vs. non-dysplastic) and ≥50% agreement on timeframe (±5 sec). Results: A total of 31 videos (124 quadrants) were reviewed by 4 expert and 4 novice VLE users. There was high agreement among expert users in 95 (77%) quadrants of which 61 (64%) quadrants were rated as dysplastic. There was high agreement among novice users in 88 (71%) quadrants of which 60 (68%) quadrants were rated as dysplastic. Expert and novice users agreed on the diagnosis of dysplasia in 44 (56%) of 78 quadrants. 17 (22%) quadrants were rated by experts as dysplastic and by novice users as non-dysplastic. 17 (22%) quadrants were rated by novice users as dysplastic and experts as non-dysplastic. There was no interobserver agreement between novice and expert groups in identifying a ROI concerning for dysplasia (kappa -0.27). Conclusion: There was no agreement in identification of dysplastic ROIs with VLE between novice and expert users, highlighting the importance of additional training of novice users in the use of this technology.