Ultrasound in Pediatric Inflammatory Bowel Disease-A Review of the State of the Art and Future Perspectives

Abstract

Inflammatory bowel disease (IBD) comprises a group of relapsing, chronic diseases of the gastrointestinal tract that, in addition to adults, can affect children and adolescents. To detect relapses of inflammation, these patients require close observation, frequent follow-up, and therapeutic adjustments. While reference standard diagnostics include anamnestic factors, laboratory and stool sample assessment, performing specific imaging in children and adolescents is much more challenging than in adults. Endoscopic and classic cross-sectional imaging modalities may be invasive and often require sedation for younger patients. For this reason, intestinal ultrasound (IUS) is becoming increasingly important for the non-invasive assessment of the intestine and its inflammatory affection. In this review, we would like to shed light on the current state of the art and provide an outlook on developments in this field that could potentially spare these patients more invasive follow-up procedures.

Keywords: Crohn’s disease; optoacoustics; pediatric inflammatory bowel disease; ulcerative colitis; ultrasound.

Figure 1

Ultrasound for assessment of inflammatory bowel diseases (A,B) Schematic cartoon of standard imaging locations for disease activity assessment in inflammatory bowel diseases as follows: terminal ileum and ascending, transverse, descending, and sigmoid colon. In healthy subjects, the intestinal wall of the terminal ileum/colon is thinner than 2 mm and it exceeds 2–2.5 mm in inflamed segments in IBD patients. (C,D) Exemplary B-mode and color Doppler images of healthy and inflamed segments of the sigmoid colon with exemplary bowel wall measurements. Displayed is a healthy child and one pediatric patient with UC. B-mode images show enlarged submucosa in the UC patient with increased blood flow measured by color Doppler. IBD = inflammatory bowel disease, Ti = terminal ileum. Created with https://www.biorender.com/ (accessed on 22 January 2024).

Figure 2

Multispectral optoacoustic imaging—molecular sensitive ultrasound. (A) Cartoon of bedside multispectral optoacoustic tomography (MSOT) to assess molecular tissue composition. (B,C) Exemplary reflected-ultrasound computed tomography (RUCT) and MSOT images of a pediatric patient with ulcerative colitis. RUCT enables real-time guidance of the investigator. Spectral unmixing of MSOT data allows differentiation and quantification of oxygenated (red) and deoxygenated (blue) blood within the bowel wall (green, region of interest). Increased levels of hemoglobin correlate with disease activity and might serve as surrogate biomarkers. Created with https://www.biorender.com/ (accessed on 22 January 2024).