The role of intestinal ultrasound in treatment monitoring has recently gained increasing interest thanks to its non-invasiveness, cost-effectiveness and largely availability. Moreover, new ultrasonographic tools, particularly dynamic contrast-enhanced ultrasound (D-CEUS) and shear wave elastography (SWE) can provide further useful information, such as a quantitative estimation of bowel intramural microvacularization and tissue stiffness.

Aim of this study is to evaluate the role of D-CEUS and SWE in predicting deep remission at 12 months from treatment induction in IBD.

Background: Clinical remission is no more considered an appropriate therapeutic target for Inflammatory Bowel Diseases (IBD) and other parameters such as endoscopic and transmural remission are now recognized as prognostic factors ("deep remission"). Correctly monitoring treatment response is crucial to rapidly adequate therapeutic algorithms avoiding complications. The role of intestinal ultrasound in treatment monitoring has recently gained increasing interest thanks to its non-invasiveness, cost-effectiveness and largely availability. Moreover, new ultrasonographic tools, particularly dynamic contrast-enhanced ultrasound (D-CEUS) and shear wave elastography (SWE) can provide further useful information, such as a quantitative estimation of bowel intramural microvacularization and tissue stiffness.

Primary objective: to evaluate the role of D-CEUS and SWE in predicting deep remission at 12 months from treatment induction in IBD.

Secondary objectives:

• To evaluate the relationship between clinical activity and CEUS/elastography parameters
• To evaluate the relationship between endoscopic activity and CEUS/elastography parameters
• To evaluate the relationship between inflammation indices and CEUS/elastography

Exploratory aims:

• To evaluate the relationship between CEUS/elastography parameters and serum biomarkers of fibrosis
• To evaluate the relationship between CEUS/elastography parameters and faecal microbiota in a subset of patients Study design: Prospective, interventional, single-center study. Methods: 50 consecutive patients with Crohn's disease or Ulcerative Colitis needing to begin biologic treatment according to international guidelines and with an affected intestinal segment detectable in B-mode ultrasound will be enrolled in the Unit of Internal Medicine and Gastroenterology of the Policlinico Gemelli. Exclusion criteria will be induction of biologic therapy in prophylaxis after surgery in Crohn's disease, lack of visualization of affected intestinal tract (eg. obesity), diagnosis of undetermined colitis, hearth failure, known allergy to ultrasound contrast agents, pregnancy and lactation. Colonoscopies, blood tests and ultrasound evaluations (B-mode ultrasound, elastography and CEUS) will be performed as per normal clinical practice. Data obtained from these procedures will be recorded and analyzed specifically for the study. The only study-specific procedures are the collection of fecal samples for microbiota evaluation, urine samples for metabolomics evaluation and an additional blood sample for evaluation of fibrosis biomarkers, both collected at the time of recruitment. The additional blood sample will be taken from the same peripheral venous access route used for blood sampling in normal clinical practice. Ileal elastography and CEUS will be performed before starting treatment and after 2/3, 8 and 16 weeks, 6 months, 12 months, 24 months and 36 months. If indicated by clinical assessment, some patients will be re-evaluated after 3 weeks. Clinical assessment will include Harvey-Bradshaw index or Mayo score, blood cell count, CRP and ESR, as per clinical practice. An additional blood sampling will be done for fibrosis biomarker evaluation. In particular, we will do multiple analysis (Bio-Plex, Biorad ) for IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12, IL-13, IL-15, IL-17, Eotaxin, basic FGF, G-CSF, GM-CSF, IFN-g, IP-10, MCP-1, MIP-1a, PDGF-bb, MIP-1b, RANTES, TNF-a, VEGF, TL -1a, TGF-b, IL-33, ST2. Data about the clinical outcome (i.e. surgery, hospitalizations, need for steroids…) and biomarkers of fibrosis will be collected up to 36 months after the start of the study.

Inclusion Criteria:

• written informed consent
• diagnosis of Crohn's disease or Ulcerative Colitis
• indication to start biologic treatment according to international guidelines
• affected intestinal segment detectable in B-mode ultrasound

Exclusion Criteria:

• induction of biologic therapy in prophylaxis after surgery in Crohn's disease
• lack of visualization of affected intestinal tract (eg. obesity)
• diagnosis of undetermined colitis
• hearth failure
• known allergy to ultrasound contrast agents
• pregnancy
• lactation