Contrast-enhanced ultrasonography in the evaluation of Crohn disease activity in children: comparison with histopathology

Background Contrast-enhanced ultrasound (US) of the bowel wall has been suggested as an alternative imaging modality for the follow-up of children with Crohn disease. Objective To evaluate the diagnostic performance of contrast-enhanced US in the estimation of Crohn disease activity in children with histopathology as the reference standard. Materials and methods In 24 children with Crohn disease confirmed on histopathology, disease activity was evaluated on 40 bowel segments using US score and subjective and quantitative contrast-enhanced US evaluation. Contrast-enhanced US evaluation included enhancement pattern analysis with a graphic representation of log time-intensity curve and calculation of kinetic parameters with the definition of thresholds for disease activity, as determined by receiver operating characteristics curve analysis. The diagnostic accuracy of US with colour Doppler imaging and subjective and quantitative contrast-enhanced US were calculated. Results Moderate or severe inflammation was identified in 18 segments and remission or mild inflammation was identified in 22 segments on histopathology. The quantitative contrast-enhanced US, namely the peak enhancement value, had 72.2% sensitivity (95% confidence interval [CI] 46.5–90.3), 100% specificity (95% CI 84.6–100.0) and 87.5% diagnostic accuracy (95% CI 73.2–95.8) in predicting moderate or severe grade inflammation at histopathology. The sensitivity, specificity and diagnostic accuracy of subjective contrast-enhanced US were 77.8% (95% CI 52.4–93.6), 77.3% (95% CI 54.6–92.2) and 77.5% (95% CI 61.6–89.2), respectively, and of US with colour Doppler imaging were 55.6% (95% CI 30.8–78.5), 86.4% (95% CI 65.1–79.1) and 72.5% (95% CI 56.1–85.4), respectively. Conclusion Quantitative contrast-enhanced US has the potential of becoming a complementary method in the evaluation of Crohn disease activity in children. Fibrosis may affect peak enhancement results and underestimate inflammatory activity.