Contrast-enhanced ultrasonography using levovist: Usefulness of diagnosis of small focal nodular hyperplasia lesions.

Differential diagnosis of focal nodular hyperplasia and hepatocellular carcinoma is clinically important because, while both are hypervascular tumors, they have vastly different prognoses. Because the spoke-wheel appearance is the primary characteristic of focal nodular hyperplasia, we attempted to detect this pattern in nodules smaller than 3 cm in diameter with contrast-enhanced ultrasonography using a contrast agent (Levovist). Four patients were examined with contrast-enhanced US: two of the patients were examined with Coded Harmonic Angio; the other two patients were examined with contrast-enhanced color and power Doppler US without harmonic imaging. Although the hepatic arteriogram showed the spoke-wheel appearance in only one tumor (diameter, 3 cm), contrast-enhanced US clearly demonstrated this characteristic in all four tumors, including three tumors that were less than 2 cm in diameter. Because it is noninvasive and can be carried out in an outpatient clinic, contrast-enhanced US is extremely useful for diagnosing small focal noduler hyperplasia lesions at sites that can be observed with US.