P0429Redefining Ulcerative Colitis Assessment Through Multimodal Virtual Chromoendoscopy: The MONET Study

Abstract Background Despite normal-appearing mucosa at white light endoscopy (WLE), up to 30% ulcerative colitis (UC) patients experience persistent histological activity, with increased risk of adverse outcomes (1). Virtual electronic chromoendoscopy (VCE) can enhance visualisation of subvisual alterations, potentially bridging this gap (2). The MONET study aims to develop a novel endoscopic scoring system based on multimodal VCE features to distinguish between quiescent and active colitis in UC. Methods We developed a scoring system incorporating three VCE modalities of the EVIS-X1 CV 1500 (Olympus, Japan) platform: Narrow-Band Imaging (NBI), Texture and Colour Enhancement Imaging (TXI) and Red Dichromatic Imaging (RDI). Eight international IBD-experienced endoscopists participated in a two-round modified Delphi process: an in-person consensus meeting followed by an anonymised online survey (Qualtrics) to select mucosal and vascular patterns representative of different UC activity grades. Consensus was defined as ≥ 75% participant agreement. Twenty-one high-quality videos encompassing varying grades of inflammation were prospectively recorded using WLE, NBI, TXI, and RDI according to a standardised protocol from the ongoing multicenter international MONET study (NCT06709209). Videos were independently scored according to selected features. Interobserver agreement was evaluated using Gwet’s AC1/AC2 coefficient. Results Overall, 12 mucosal and 12 vascular features were identified (Table 1, Figure 1). Among mucosal features, crypt architecture (AC1 0.76), microerosions (AC1 0.76) and erosions (AC1 0.80) demonstrated substantial agreement. For vascular features, crowded and intramucosal bleeding showed substantial agreement (AC1 0.78 and 0.73, respectively), while honeycombing showed moderate agreement (AC1 0.50). NBI-specific features, including honeycombing, branching vessels, and intramucosal bleeding, demonstrated substantial agreement (AC1 0.63, 0.73, and 0.65, respectively). Using TXI, crypt architecture (AC1 0.7), microerosions (AC1 0.72), and erosions (AC1 0.78) yielded substantial agreement. Deep vessels visibility, assessed through RDI, yielded substantial agreement (AC1 0.77). The agreement for the remaining features was almost perfect. The anonymised Delphi voting survey confirmed consensus for all 24 identified elements into the final MONET score. Conclusion The novel VCE-based MONET score demonstrated high interobserver agreement, supporting its robustness and clinical relevance. It holds potential to bridge the gap between endoscopic assessment and histologic activity, particularly in mildly active UC. Multicenter prospective validation is underway to support broader adoption and future integration into AI-assisted endoscopic evaluation. References: 1. Yoon H, Jangi S, Dulai PS, et al. Incremental Benefit of Achieving Endoscopic and Histologic Remission in Patients With Ulcerative Colitis: A Systematic Review and Meta-Analysis. Gastroenterology. 2020;159(4):1262-1275.e7. doi:10.1053/j.gastro.2020.06.043 2. Iacucci M, Smith SCL, Bazarova A, et al. An International Multicenter Real-Life Prospective Study of Electronic Chromoendoscopy Score PICaSSO in Ulcerative Colitis. Gastroenterology. 2021;160(5):1558-1569.e8. doi:10.1053/j.gastro.2020.12.024 Conflict of interest: Iacucci, Marietta: Grant: Pentax, Olympus, Eli lilly,Helmsley Personal Fees: Pentax, Pfitzer, Janssen,EliLilly,J & J Dr. Pugliano, Cecilia Lina: None Zammarchi, Irene: No conflicts Lo Bello, Antonio: No conflict of interest Santacroce, Giovanni: No conflict of interest Nardone, Olga Maria: Advisory board fees from Eli Lilly, Nestlè, Janssen Speaker fees from AbbVie, Janssen, Eli Lilly, Ferring, Alfa Sigma, Recordati, Noòs, and Pfizer Hughes, Robert: No conflict of interest Tan, Chin Kimg: No conflict of interest Dal Buono, Arianna: speaker’s fees from AbbVie, Alphasigma, Ferring, Lilly, Janssen, and Celltrion Ditonno, Ilaria: None Principi, Maria Beatrice: No conflict of interest Ghosh, Subrata: None None None Bisschops, Raf: Grant: Pentax Europe, Medtronic, Norgine Personal Fees: Pentax Europe, Fujifilm, Norgine, Medtronic, Ipsen, Alfasigma, Viatris, Endostart, Falk Foundation Non-financial Support: Pentax Europe, Fujifilm, Boston Scientific, Olympus, Erbe, Norgine Maeda, Yasuharu: No conflict of interest