Objective To compare the contrast-enhanced ultrasound (CEUS) features of hepatocellular adenoma (HCA) and focal nodular hyperplasia (FNH) smaller than 3 cm.
Methods 25 HCA lesions and 48 FNH lesions with maximum diameter smaller than 3 cm confirmed by histopathological examination after surgery were enrolled in this study. After intravenous bolus injection of SonoVue, the CEUS features such as enhancement pattern in the arterial phase, enhancement intensity in portal venous and late phase, feeding artery, central scar and subcapsular vascular enhancement were analyzed.
Results All HCA and FNH lesions showed rapid enhancement in arterial phase. 21(84.0%) HCAs presented overall enhancement, while 41(85.4%) FNHs presented gushing-spring enhancement (P < 0.001). In portal venous phase, 10(40%) HCAs showed hypoenhancement, FNHs continued hyperenhancement (10, 20.8%) or isoenhancement (38, 79.2%; P < 0.001). During late phase, 13 (52.0%) HCAs and 2(4.2%) FNHs showed hypoenhancement (P=0.003). The detection rate of feeding artery in HCAs was significantly lower than that in FNHs (12.0% vs 52.1%, P=0.001), whereas the detection rate of subcapsular vascular enhancement in HCAs was significantly higher than that in FNHs (56.0% vs 10.4%, P < 0.001). The sensitivity, specificity and accuracy of "overall hyperenhancement in the arterial phase" or "subcapsular vascular enhancement" in CEUS for HCA were 88.0%, 87.5% and 87.7%, respectively; those of "gushing-spring hyperenhancement in the arterial phase", or "central scar", or "continuous hyper- or iso-enhancement in late phase" in CEUS for FNH were 93.8%, 84.0% and 93.2% respectively.
Conclusions For liver lesion smaller than 3 cm, overall hyperenhancement in the arterial phase and subcapsular vascular enhancement in CEUS indicate HCA, while gushing-spring hyperenhancement in the arterial phase, central scar, and continuous hyper- or iso-enhancement in late phase in CEUS indicate FNH.
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