Role of Intestinal Ultrasound in Treat to Target Strategy in the Management of Inflammatory Bowel Disease : the IUS-TTT Study

This study aims to evaluate the role of bedside Intestinal Ultrasound (IUS) as a cost-effective, non-invasive, and well-tolerated procedure within the Treat-to-Target strategy for managing Inflammatory Bowel Disease (IBD). Despite its growing use, therapeutic targets for IUS-guided treatment remain inadequately defined. The study will investigate the feasibility of IUS in monitoring transmural response and remission, and its potential to predict clinical and biochemical responses at 3 months, as well as mucosal healing at 6 and 12 months. By incorporating IUS into routine clinical care, we aim to enhance disease management and optimize therapeutic outcomes for patients with ulcerative colitis and Crohn's disease.

This prospective observational pilot study aims to assess the role of Intestinal Ultrasound (IUS) in the management of active Inflammatory Bowel Disease (IBD) over a 6-12 month period at a single tertiary center. The primary objective is to determine the incidence of transmural response at short-term and transmural remission at long-term follow-up. Secondary objectives include evaluating the predictive role of IUS performed at weeks 2-6 for clinical and biochemical response at 3 months, and as a predictor of mucosal healing at 6-12 months. Adult patients with active IBD, defined by endoscopic criteria (Ulcerative Colitis Endoscopic Index of Severity \[UCEIS\] ≥ 2 for ulcerative colitis and Simple Endoscopic Score for Crohn's Disease \[SES-CD\] ≥ 3 for Crohn's disease), will be enrolled. Exclusion criteria include age \<18 years, Crohn's disease restricted to non-terminal ileum small bowel or gastroduodenal area, normal bowel wall thickness in all segments at week 0, isolated proctitis in ulcerative colitis, body mass index (BMI) \>30, and pregnancy. Participants will undergo IUS at baseline, 2-6 weeks, 12 weeks, and 6-12 months, along with measurements of fecal calprotectin, C-reactive protein (CRP), Harvey-Bradshaw Index (HBI), and Simple Clinical Colitis Activity Index (SCCAI), and ileocolonoscopy at baseline and 6-12 months. IUS parameters will include bowel wall thickness, vascularization, wall stratification, mesentery features, and complications. The Milan Ultrasound Criteria (MUC) for ulcerative colitis and the Bowel Ultrasound Score (BUSS) and International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) for Crohn's disease will be used to assess disease activity. Outcomes will measure the incidence of transmural response and remission, and the predictive role of early IUS for clinical, biochemical, and mucosal healing. Ethical clearance is obtained, and informed consent will be taken from all participants. The study aims to enroll 100 patients to gather sufficient data for analysis.

Eligibility Criteria:
Inclusion Criteria:

* Adults over the age of 18 years.
* Active Crohn's disease, defined as a Simple Endoscopic Score for Crohn's Disease of 3 or higher.
* Active ulcerative colitis, defined as an Ulcerative Colitis Endoscopic Index of Severity of 2 or higher.

Exclusion Criteria:

* Age \< 18 years
* Intestinal ultrasound for assessment of response to therapy
* Intestinal ultrasound for clinically asymptomatic disease
* Pregnancy and lactating mothers