Extracorporeal ablation of liver tissue by high-intensity focused ultrasound.

High-intensity focused ultrasound (HIFU) may produce a well-delineated lesion of coagulation necrosis in deep organs, by means of an extracorporeal transducer. Applications of this method to the liver in animal models have been studied for many years. The effects of HIFU on the normal liver parenchyma and on hepatic tumors are reviewed. In the normal rabbit liver in vivo we showed the relation between intensity levels and exposure times and the need to adapt intensity to the depth of the target. No severe complications were observed when an intensity of 1,000 W/cm2 was used. HIFU is a noninvasive method for the local destruction of liver tumors. In experimental models, safety and efficacy were demonstrated. HIFU may be interesting for the treatment of some human liver tumors.