Mo1501 Attending Endoscopists and Gastroenterology (GI) Trainees Have Similar Performance When Characterizing Diminutive Colorectal Polyps With Narrow Band Imaging (NBI)

Methods: Diagnostic criteria were developed from twenty VLE scans of endoscopic mucosal resections (EMR) with corresponding histology (10 dysplastic, 10 nondysplastic). Non-dysplastic scans were more likely to contain mucosal layering longer than 1 mm compared to dysplastic EMRs, pZ0.001. The percentage of the scan involved by mucosal layering was also significantly higher for non-dysplastic compared to dysplastic scans (60.4% versus 15.6%, pZ0.001). Validation was performed on a set of 32 EMR scans (18 dysplastic and 14 non-dysplastic) that were independently scored by two blinded reviewers with experience in VLE using the diagnostic algorithm described in figure 1. Results were compared to histology and sensitivity, specificity and rater agreement were calculated for the image set. Results: A total of 15 EMR scans were rated as dysplastic and 11 scans were rated as non-dysplastic by both reviewers. The two reviewers rated 3 non-dysplastic scans as dysplastic and 3 dysplastic scans as non-dysplastic. Agreement between reviewers was substantial (kappa 0.81). Compared to histology, the sensitivity and specificity of these criteria were 95% and 94% respectively with an overall 81% diagnostic accuracy. Conclusion: We present a new set of criteria with high sensitivity and specificity for detection of dysplasia in BE using VLE. These criteria appear superior to previously published criteria, however need further prospective validation. Diagnostic algorithm for dysplasia in Barrett’s esophagus using volumetric laser endomicroscopy. (A) Dysplastic endoscopic mucodal resection volumetric laser endomicroscopy scan showing complete effacement of mucosal layering and (B) non-dysplastic scan showing partial effacement, black arrows. Mo1501 Attending Endoscopists and Gastroenterology (GI) Trainees Have Similar Performance When Characterizing Diminutive Colorectal Polyps With Narrow Band Imaging (NBI) Emily K. Ward*, Swati G. Patel, Amit Rastogi, Ajay Bansal, Hyungjin Kim, Lindsay Hosford, Dennis J. Ahnen, Sachin Wani University of Colorado, Centennial, CO; Veterans Affairs Medical Center, Denver, CO; University of Michigan, Ann Arbor, MI; Veterans Affairs Hospital, Ann Arbor, MI; Veterans Affairs Medical Center, Kansas City, KS Background: While experts can accurately characterize diminutive colorectal polyp histology using NBI, there is limited data comparing the accuracy of GI trainees AB460 GASTROINTESTINAL ENDOSCOPY Volume 79, No. 5S : 2014 and attending endoscopists in characterization of diminutive colorectal polyp histology using NBI. Aim: To compare diagnostic performance of attending endoscopists and GI trainees to determine diminutive colorectal polyp histology. Methods: Attending endoscopists, with no prior training in NBI, at an academic tertiary referral center were invited to view a 20 min audiovisual teaching tool that described validated NBI criteria to distinguish polyp histology (adenoma vs. hyperplastic polyp). Participants then watched 80 short videos of diminutive polyps under NBI without magnification (52 adenomas, 28 hyperplastic), recorded their histology prediction and degree of confidence (highR90%, low-!90%) for each polyp and then received targeted feedback on actual histology. Performance was evaluated by comparing predicted and the actual histology. Accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were compared to a historical group of 12 GI trainees who underwent the same training and evaluation method. Multi-level logistic regression model adjusting for between participant variability was used to compare performance between attendings and trainees. Inter-observer agreement in polyp classification was calculated using k statistics. Results: Ten attending endoscopists with varying years of experience (!5 to O20 yrs) and annual endoscopy volume (150 to O500 colonoscopies/year) completed the study. Twelve GI trainees (3-1st year, 4-2nd year, 5-3rd year) with varying levels of colonoscopy experience (51 to O500 colonoscopies performed) had previously completed the study. There was no significant difference between attending and GI trainee performance and both attendings and trainees achieved O90% performance by all measures for high confidence diagnoses (Table 1). For high confidence diagnoses, overall accuracy for attendings was 96% (95% CI 94-97) compared to 97% (95% CI 95-98) for GI trainees. Both attending endoscopists and trainees achieved R 90% accuracy by the third quartile of videos (96% vs. 93%, respectively) (Table 2). Inter-observer agreement (k) among attending endoscopists was similar to trainees (0.80 vs. 0.71, pZ0.26). Conclusion: A novel training tool was equally effective in teaching attending endoscopists and GI trainees to characterize diminutive colorectal polyp histology using NBI with similar thresholds for achieving an accuracy of R90%. This study demonstrates that characterization of diminutive polyp histology using NBI can be easily learned using a simple classification system. The next step will be to determine the performance of trainees and attendings in the real-time prediction of polyp histology using NBI. Table 1. Comparison of Attending and Trainee Performance (95% CI) Attending Endoscopists Trainees www.giejourn P value* Overall (N[800) Confidence Level Overall (N[908) Confidence Level Low (N[226) High (N[574) Low (N[257) High (N[651) Accuracy (%) 91 (89-93) 79 (74-85) 96 (94-97) 90 (88-92) 72 (67-78) 97 (95-98) 0.96 Sensitivity (%) 91 (89-94) 81 (74-87) 96 (94-98) 89 (87-92) 71 (64-77) 96 (95-98) 0.87 Specificity (%) 90 (85-93) 76 (64-85) 95 (91-97) 91 (88-94) 75 (66-84) 97 (94-99) 0.91 PPV (%) 94 (92-96) 87 (81-92) 97 (95-99) 95 (93-97) 85 (79-91) 98 (97-99) 0.88 NPV (%) 85 (81-89) 66 (55-76) 93 (89-96) 82 (78-92) 57 (48-66) 94 (91-97) 0.87 PPV, positive predictive value; NPV, negative predictive value *p value represents the comparison between overall attending endoscopists’ and trainees’ performance Table 2. Comparison of Attending and Trainee Performance (95% CI) by video block.