Background/aims: The aim was to examine the efficacy of contrast-enhanced ultrasound (US) with Sonazoid to demonstrate ultrasonically unrecognizable hypervascular hepatocellular carcinoma (HCC) and apply percutaneous US-guided treatments.
Methods: The subjects of this prospective study were 44 cirrhotic patients with 55 hypervascular lesions (12.7+/-4.5 mm) found by contrast-enhanced computed tomography but unrecognized by non-contrast US. Contrast-enhanced US was performed to demonstrate these hepatic lesions after an intravenous injection of Sonazoid (0.0075 ml/kg). The sonograms in both the early phase (for 1 min after injection) and the late phase (5-10 min after) were taken in the harmonic imaging mode under a low mechanical index (0.24-0.3).
Results: Fifty-three lesions were demonstrated by contrast-enhanced US, 52 with positive enhancement in the early phase and 44 with negative enhancement in the late phase. Percutaneous US-guided treatments were successfully performed for 42 lesions (ethanol injection in 20 and radiofrequency ablation in 22) in 32 patients with reference to contrast-enhanced US findings. Six patients were treated by transarterial chemoembolization alone because they had more than three lesions in the liver. In the remaining seven lesions in six patients, six were diagnosed as non-HCC lesions: five with vascular abnormalities such as arterioportal or arteriovenous communication and the other one with benign lesion in alcoholic liver disease. These six lesions and one HCC lesion with severe liver damage were followed up without any treatment.
Conclusions: As the detectability of ultrasonically unrecognizable hypervascular HCC improved by contrast-enhanced US with Sonazoid, a wider application of percutaneous US-guided treatments may be possible.