Intestinal Ultrasound in the Diagnostic Assessment of Inflammatory Bowel Disease and Infectious enterocolitis: A Case-Based Narrative Review

Background: Intestinal ultrasound (IUS) provides rapid, noninvasive assessment of transmural inflammation in inflammatory bowel disease (IBD). In clinical practice, infectious enterocolitis frequently mimics IBD activity or complicates established diseases, creating diagnostic uncertainty at presentation and increasing the risk of inappropriate treatment escalation. Summary: This case-based narrative review describes how IUS can support diagnostic assessment in patients with suspected IBD activity or infectious enterocolitis. We summarize core IUS parameters, including bowel wall thickness, mural vascularity, and bowel wall stratification, along with supportive findings, such as perienteric inflammatory fat, lymphadenopathy, and haustral changes. Validated IUS-based approaches for ulcerative colitis (UC) and Crohn’s disease (CD), including the Milan Ultrasound Criteria (MUC), International Bowel Ultrasound Segmental Activity Score (IBUS-SAS), and transperineal ultrasound (TPUS) for rectal assessment, are summarized. Using representative cases, we highlight characteristic pattern-based IUS findings across common causes of infectious enterocolitis and intestinal tuberculosis, focusing on disease distribution, symmetry, perienteric involvement, and short-interval evolution on follow-up examinations. These findings will help refine the differential diagnosis and inform subsequent testing in real-world clinical settings. Key Messages: IUS provides readily available, segment-based information that complements clinical evaluation when differentiating IBD activity from infectious enterocolitis. Pattern recognition on IUS may enhance diagnostic safety and guide subsequent investigations; however, findings should be interpreted in the context of clinical presentation and additional diagnostic modalities.