Update on intestinal ultrasound in pediatric inflammatory bowel disease

Intestinal ultrasound (IUS) is an accessible imaging tool in pediatric inflammatory bowel disease (IBD), its validation and standardization are a topic of intensive ongoing research. Here we provide an update on recent evidence including interim results from new studies.

Literature search was performed using PubMed and OpenEvidence on IUS in pediatric IBD and the following subtopics: (1) validation of IUS in pediatric IBD; (2) bowel wall thickness (BWT); (3) Doppler-based evaluation; (4) mesenteric fat; (5) fibrostenosis and intestinal strictures; (6) comparison of different scoring systems; and (7) IUS in pediatric IBD monitoring. Furthermore, conference abstracts and poster presentations from major conferences were screened to identify ongoing studies with relevant preliminary findings.

IUS specificity and sensitivity for inflammation was found to be above 80-90% for the bowel segments accessible to ultrasound (colon, terminal ileum), but more limited for small bowel. Consensus is emerging for a threshold value of < 2.5 mm for BWT in deep remission of pediatric IBD, which is lower than in adults. In multiple studies, BWT alone correlated as well as more complex IUS-based scores with endoscopy and laboratory markers of inflammation. The Chicago Mesenteric Fat Index (CMFI) was developed for quantification of mesenteric fat and may improve standardization and reproducibility in research and clinical applications.  Conclusion: Significant recent progress in standardization and validation of IUS in pediatric IBD will most likely lead to its widespread application in outpatient and bedside monitoring including possible adoption of IUS based endpoints in clinical studies.

• Intestinal ultrasound is gaining importance in the diagnostics and management of pediatric inflammatory bowel disease.

• Simplified ultrasound assessment measuring bowel wall thickness alone may be as informative as more complex scores. A consensus new cut-off value <  2.5 mm for bowel wall thickness in children is emerging. • A standardized quantification system called the Chicago Mesenteric Fat Index in pediatric inflammatory bowel disease has been proposed.