Contrast-enhanced ultrasound for the diagnosis of hepatic adenoma.

Nine hepatic adenomas (HA) diagnosed by contrast-enhanced ultrasound (CEUS) among 123 liver lesions (89 patients) were evaluated retrospectively; five were confirmed through pathological diagnosis. Time-intensity curves (TIC), contrast medium arriving time (AT), peak time (PT) and retrogression time (RT) for HA were compared with 30 hepatocellular carcinomas (HCC) and six focal nodular hyperplasias (FNH). Significant differences existed between HA and poorly-differentiated HCC in AT, PT and RT, and between HA and well-differentiated HCC in AT. Differential diagnosis between HA and FNH was determined only through their different perfusion and arterial morphological features: HA showed typical perfusion characteristic of 'fast-in, slow-out', with a centripetal or mixed-filling pattern in the arterial phase, while FNH showed a centrifugal filling pattern. In conclusion, CEUS was helpful for identifying HA but it may be relatively difficult to distinguish between HA and some well-differentiated HCC or FNH.