Hepatic focal nodular hyperplasia: contrast-enhanced ultrasound findings with emphasis on lesion size, depth and liver echogenicity.

OBJECTIVE: To correlate contrast-enhanced ultrasound (CEUS) findings of hepatic focal nodular hyperplasia (FNH) with lesion size, depth and liver echogenicity and to compare CEUS with baseline US. METHODS: Two radiologists evaluated baseline US and CEUS examinations of 92 FNHs (mean size: 3.1 +/- 1.7 cm) in 71 patients (59 women and 12 men) to detect the "spoke-wheel" sign, central scar and feeding vessel. The FNHs were grouped and analysed by dimension, depth and liver echogenicity. RESULTS: At least one sign could be detected at CEUS in 27 out of 36 (75%) FNHs larger than 3 cm and in 17 out of 56 (30%) FNH measuring 3 cm or less (p < 0.0001). No statistically significant differences were noted between lesion depth or liver echogenicity and detection rate of these signs at CEUS (p > 0.05) as well as between CEUS or baseline US/CD with regard to lesion size, depth or liver echogenicity (p > 0.05). CONCLUSION: The detection rate of the central scar and spoke-wheel sign in FNH at CEUS is strongly dependent on lesion size and CEUS can confidently diagnose most FNHs larger than 3 cm.