Contrast-enhanced ultrasound in the diagnosis of pediatric focal nodular hyperplasia and hepatic adenoma: interobserver reliability

Background Focal nodular hyperplasia and hepatic adenoma are rare liver tumors in which specific features on contrast-enhanced ultrasound (US) have been reported but are little known in children. Objective To assess the interobserver agreement in diagnosing and differentiating focal nodular hyperplasia and hepatic adenoma in children using established adult contrast-enhanced US characteristics. Materials and methods Thirty children with a definite or probable diagnosis of focal nodular hyperplasia or hepatic adenoma on magnetic resonance imaging (MRI)/histology who underwent contrast-enhanced US studies were included. Typical and additional contrast-enhanced US features of focal nodular hyperplasia and hepatic adenoma were included. The lesions were classified as definite/probable focal nodular hyperplasia, definite/probably hepatic adenoma or unclassified. The interobserver kappa of contrast-enhanced US characteristics was calculated. Results Focal nodular hyperplasia and hepatic adenoma in children demonstrate contrast-enhanced US characteristics similar to those in adults. Among the nine lesions with confirmed histological diagnosis, correct diagnosis was made in 7 (77.8%) based on contrast-enhanced US criteria. Two lesions were unclassified by both observers due to a mixed arterial filling pattern. Interobserver kappa for contrast-enhanced US diagnosis was 0.64 ( P <0.0001). Conclusion There is a good interobserver kappa for separating focal nodular hyperplasia from hepatic adenoma in children using established adult contrast-enhanced US features.