Echogenicity of experimental liver ethanol injections

Percutaneous ethanol injection therapy under sonographic guidance suffers from the occasional adverse spread of ethanol. We tried to optimize the technique to obtain the maximal echogenicity of injections. Eight dead pig livers were injected with ethanol and the consequent echogenicity was correlated with the time lapse after the injection, the speed of injection, the injected dose and the concentration of ethanol. For the sake of comparison, ethanol was also injected into processed sour milk. The injected lesions became smaller (P < 0.001), less sharply demarcated and less echogenic (P < 0.001) with time. Speeding up the injection (P < 0.05) and concentrating the ethanol (P < 0.05) increased echogenicity, whereas enlarging the dosage did not. Injections of ethanol into processed sour milk induced hyperechoic zones similar to the liver injections. It is concluded that quick injections of concentrated ethanol would be best detected. Injections should be monitored while they are still taking place, because the echogenicity will soon decrease. This immediate echogenicity seems to be caused by flow and the inherent properties of ethanol.