[Transarterial enhanced ultrasonography examination of hepatocellular carcinoma using CO2]

The findings of enhanced ultrasonography under the injection of microbubbles of carbon dioxide into a hepatic artery (CO2-US) were evaluated in the patients with hepatocellular carcinoma (HCC). They were as follows. Most nodules showed early (within 3 seconds) stronger enhancement compared to the surrounding hepatic parenchyma, remaining the enhancing effects more longer than the surround. A few nodule showed isoenhance or nonenhancement. However, metastatic cancer of the liver often showed the early enhancement only at the edge of tumor. In hepatic hemangioma, only the spotty enhancement in the tumor and or the later (later than 4 seconds) enhancement at the edge of tumor was showed. The hyperenhanced mass was detected more often in a larger HCC and revealed to be a relatively poorly differentiated HCC with the capsule formation.