[Carbon dioxide as an intra-arterial contrast agent in echography: a technic for its preparation and the preliminary results in assessing hepatocarcinoma vascularization].

This paper reports on an original method to prepare a contrast agent consisting of CO2 microbubbles to be injected i.a. during ultrasound examinations (ultrasound angiography-USA), whose value was investigated in the study of tumor neovascularity in HCC patients. Thirty-five HCC patients underwent USA. CO2 was drawn out from a gas container under pressure and, through a sublimation process, made available in predetermined quantities in test tubes. USA was performed during angiography in 9 cases and immediately before arterial chemoembolization in the other 26 cases. In 51 lesions vascularity was evaluated with conventional angiography, USA and lipiodol CT. USA demonstrated lesion hypervascularity in 91% of cases, as confirmed by lipiodol CT (88%), versus 72.4% of angiography. In 3 of 35 patients USA demonstrated 6 more lesions undetected by other modalities: two of them were proved to be HCC and adenomatous hyperplasia at percutaneous biopsy. USA is a cost-effective procedure, which is easy to perform during conventional angiography: it is more sensitive than conventional angiography in the study of lesion neovascularity and can help plan lesion management, anticipating the results of chemoembolization. The role of USA in the diagnosis and treatment of HCC is, however, still to be defined.