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

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. 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. 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). 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.