P0570 Role of dynamic contrast-enhanced ultrasound (D-CEUS) in predicting clinical remission to advanced therapy in ulcerative colitis - a monocenter prospective pilot study

Abstract Background Ulcerative Colitis (UC) is a chronic inflammatory disease characterized by periods of relapse and remission. While colonoscopy is currently the gold standard for assessing disease activity, its invasiveness, low patient tolerance and associated risks make it unsuitable for frequent monitoring of intestinal inflammation. Despite these challenges, a "treat-to-target" approach is crucial in the era of biological therapies. Intestinal Ultrasound (IUS) offers a non-invasive, cost-effective and well-tolerated alternative to monitor treatment response. Indeed, the Milan Ultrasound Criteria (MUC), based on B-mode and color-doppler parameters, have been recently developed to assess disease activity in UC1,2. Dynamic Contrast-Enhanced Ultrasound (D-CEUS) allows visualization of tissue microvascularization, providing objective quantitative parameters derived from time-intensity curve analysis, potentially representing a promising tool to quantify bowel inflammation. The aim of our study was to assess the role of D-CEUS in predicting 6 months clinical remission to advanced therapies (biologic and small molecules). Methods We prospectively enrolled consecutive UC patients starting a new advanced treatment for clinical practice. Patients underwent IUS, D-CEUS and clinical assessment at baseline and at 8 (T1), 16 (T2) and 24 (T3) weeks after starting treatment. According to STRIDE-II consensus3, clinical remission at T3 was defined as partial Mayo score <3 and no subscore <1. Time-intensity curves were analyzed through VueBox® software (figure 1). Patients needing surgery or treatment change before T3 were classified as "non-responders". Logistic regression analysis was performed to evaluate the predictive role of D-CEUS in achieving clinical remission at T3. Statistical significance was defined as p<0.05. Results 40 patients were enrolled (mean age 39±13 years, 60% males), 44.4% (n=18) of which had previously failed at least one line of advanced therapy. At T3, 50% of patients achieved clinical remission (n=20). Univariate logistic regression analyses showed that reductions of Peak Enhancement (PE) and Wash-in Perfusion Index (WiPI) at T2 were predictive of clinical remission at T3 (OR=0.99, p=0.032 and OR=0.25, p=0.036 respectively). Moreover, the percentage changes between T2 and T0 (△% T2 – T0) of PE and WiPI were associated with 6 months clinical remission (OR=0.19 p=0.019 and OR=0.26 and p=0.04, respectively). Lastly, our results confirmed the value of MUC (at T1 and T2) in predicting clinical remission at T3 (OR=0.62, p=0.03 and OR=0.73, p=0.048, respectively). Conclusion D-CEUS provides early predictors of 6 months clinical remission in UC patients treated with advanced therapies. References 1.Allocca M, Fiorino G, Bonovas S, Furfaro F, Gilardi D, Argollo M, Magnoni P, Peyrin-Biroulet L, Danese S. Accuracy of Humanitas Ultrasound Criteria in Assessing Disease Activity and Severity in Ulcerative Colitis: A Prospective Study. J Crohns Colitis. 2018 Nov 28;12(12):1385-1391. doi: 10.1093/ecco-jcc/jjy107. PMID: 30085066; PMCID: PMC6260119. 2.Allocca M, Filippi E, Costantino A, Bonovas S, Fiorino G, Furfaro F, Peyrin-Biroulet L, Fraquelli M, Caprioli F, Danese S. Milan ultrasound criteria are accurate in assessing disease activity in ulcerative colitis: external validation. United European Gastroenterol J. 2021 May;9(4):438-442. doi: 10.1177/2050640620980203. Epub 2021 Feb 16. PMID: 33349199; PMCID: PMC8259285. 3.Turner D, Ricciuto A, Lewis A, D'Amico F, Dhaliwal J, Griffiths AM, Bettenworth D, Sandborn WJ, Sands BE, Reinisch W, Schölmerich J, Bemelman W, Danese S, Mary JY, Rubin D, Colombel JF, Peyrin-Biroulet L, Dotan I, Abreu MT, Dignass A; International Organization for the Study of IBD. STRIDE-II: An Update on the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) Initiative of the International Organization for the Study of IBD (IOIBD): Determining Therapeutic Goals for Treat-to-Target strategies in IBD. Gastroenterology. 2021 Apr;160(5):1570-1583. doi: 10.1053/j.gastro.2020.12.031. Epub 2021 Feb 19. PMID: 33359090.