There is good agreement between MR enterography and bowel ultrasound with regards to disease location and activity in paediatric inflammatory bowel disease

Aim: To investigate concordance of bowel ultrasound and magnetic resonance enterography (MRE) in identifying active disease in children with inflammatory bowel disease. Materials and methods: The imaging of children with inflammatory bowel disease who had undergone bowel ultrasound and MRE within 30 days were retrospectively reviewed, from January 2009 to November 2015. Ultrasound was without oral contrast medium; MRI was conducted with patients unsedated with oral contrast medium and gadolinium. Imaging data included bowel thickness, markers of activity, and complications. Endoscopy and biopsy reports were also reviewed. Results: Forty-nine patients (median age 14 years, 33 male) met the inclusion criteria, and 31 children also had endoscopy within 30 days. Active inflammation was seen in 17.6% of bowel segments at ultrasound and 17.3% at MRE. There was good agreement between ultrasound and MRE on the location and activity of disease (Cohen's kappa 0.75, 95% confidence interval [CI]: 0.66–0.83). One patient had an inflammatory phlegmon detected at MRE only; there was no other significant discrepancy in identifying complications. In patients with histopathology, MRE, and ultrasound demonstrated high specificity 85.1% (77.9–90.6) and 86.6% (79.6–91.8) at the bowel segment level. Technical difficulties, including poor tolerance of oral contrast medium and movement, were more common in MRE. Conclusion: There was good concordance between MRE and ultrasound for disease location and activity, and fewer technical difficulties with ultrasound. Bowel ultrasound is useful in children, and its use is advocated. - Highlights: • There is good agreement between ultrasound and MRI in paediatric IBD. • Fewer technical difficulties were reported with ultrasound than MRI. • Using histology as the gold standard, both MRI and US show high specificity. • We find ultrasound is well tolerated in children and advocate its use.