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.