PURPOSE: The performance of endoscopic evaluation of ulcerative colitis (UC) using conventional scoring, including Mayo endoscopic subscore (MES) and ulcerative colitis endoscopic index of severity (UCEIS), is not satisfactory. Recently, the usefulness of novel image-enhanced endoscopy (IEE) such as texture and color enhancement imaging (TXI) and red dichromatic imaging (RDI) has been reported in the endoscopic evaluation of UC. We evaluated the performance of IEEs in UC, particularly focusing on the correlation with MES and UCEIS, and prediction of relapse. METHODS: This is a prospective, observational study. UC patients in clinical remission who underwent colonoscopy with evaluation of IEEs and follow-up for >
3 months were analyzed. TXI and RDI were evaluated using the previously reported scoring system (TXI 0-2 and RDI 1-4). The IEE scores were compared with the conventional scoring, fecal calprotectin levels, and histological findings using Geboes score, and patient's clinical relapse rate stratified by each IEE score was examined. RESULTS: Both TXI and RDI scores were well-correlated with MES and UCEIS (both p <
0.001), fecal calprotectin levels (p = 0.015 and p = 0.006), and histology evaluated with Geboes score. In the Geboes subscore, the subscore 2B (neutrophil infiltration in lamina propria) was the most correlated with each endoscopic scoring. RDI 3-4 was significantly correlated with subsequent relapse (hazard ratio 3.56, 95% confidence interval 1.13-11.24), but TXI scoring did not predict relapse significantly. CONCLUSION: The assessment using RDI could be a convenient and useful endoscopic evaluation method for predicting the prognosis of UC.