Looking Beyond the Mucosa: A New Scoring System for Mesenteric Fat in Intestinal Ultrasound

The management of inflammatory bowel disease has increasingly embraced non-invasive tools to assess disease activity and guide treatment, particularly in pediatric Crohn’s disease (CD), in which minimizing radiation exposure and invasive procedures is critical. Intestinal ultrasound (IUS) has become a cornerstone in this setting, with findings that correlate strongly with endoscopic inflammation.1 Bowel wall thickness (BWT) remains the most established sonographic parameter,2 while additional features such as color Doppler signal, bowel wall stratification, and mesenteric fat (MF) further enhance IUS’ diagnostic utility. Mesenteric fat, also known as “creeping fat,” appears on IUS as a hyperechoic layer extending from the serosa into the mesentery and surrounding the bowel wall.3 Its presence is a recognized marker of inflammation in CD, and is linked to long-term clinical outcomes.4 Despite its importance, there is currently no standardized method for MF assessment using IUS. Existing approaches often rely on subjective, binary evaluations, which yield suboptimal interobserver agreement.5 Furthermore, binary scoring is unable to capture subtle changes in MF over time. Consequently, few IUS scoring systems incorporate MF, and those that do apply inconsistent criteria.2,6,7