The Paddington International Virtual Chromoendoscopy Score in ulcerative colitis exhibits very good inter-rater agreement after computerized module training: a multicenter study across academic and community practice (with video)

Abstract Introduction Electronic virtual chromoendoscopy (EVC) can demonstrate ongoing disease activity in ulcerative colitis (UC), even when Mayo subscores suggest healing. However, applicability of EVC technology outside the expert setting has yet to be determined. Methods 15 participants across 5 centers reviewed a computerized training module outlining high-definition (HD) and EVC (i-Scan) colonoscopy modes. Interobserver agreement was then tested (Mayo score, UCEIS and the P addington I nternational virtual C hromoendo S copy S c O re [PICaSSO] for UC), using a colonoscopy video library (n=30 cases reviewed pre- and n=30 post-training). Knowledge sustainability was re-tested in a second round (n=42 cases; 9/15 participants), 6 months after training provision. Results Pre-training intraclass correlation coefficients (ICC) were good for the Mayo endoscopic subscore (ICC:0.775), UCEIS scoring erosions/ulcers (ICC:0.770) and UCEIS overall (ICC:0.786), and for mucosal (ICC:0.754) and vascular components of PICaSSO (ICC:0.622). For the vascular components of UCEIS, agreement was only moderate (ICC:0.429), and did not enhance post-training (ICC:0.417); unlike for PICaSSO, which improved (mucosal ICC:0.848; vascular: 0.746). Histological correlation using the New York Mt. Sinai System was strong for both PICaSSO components (Spearman's rho for mucosal: 0.925, and vascular: 0.873; p 0.001 for both). Moreover, accuracy in specifically discriminating quiescent from mild histological strata was strongest for PICaSSO (AUROC for mucosal: 0.781; vascular: 0.715), compared with Mayo (AUROC:0.708) and UCEIS (AUROC for UCEIS overall: 0.705; vascular: 0.562; bleeding: 0.645; erosions/ulcers: 0.696). Inter-rater reliability for PICaSSO was sustained by round 2 participants (Round 1 and 2 ICC for mucosal: 0.873 and 0.869, respectively; and vascular: 0.715 and 0.783, respectively), together with histological correlation ( rho mucosal: 0.934, vascular: 0.938; p 0.001 for both). Conclusion PICaSSO demonstrates good interobserver agreement across all levels of experience, providing excellent correlation with histology. Given ability to discriminate subtle endoscopic features, PICaSSO may be applied to refine stratified treatment paradigms for UC patients.