The use of a microbubble agent to enhance rabbit liver destruction using high intensity focused ultrasound

Liver tissues in New Zealand rabbits were ablated using high intensity focused ultrasound (HIFU, 14 300 W/cm², 1.0 MHz). The animals were intravenously administered 0.2 ml of microbubble agent in the experimental (n = 20) group and an isovolumetric normal saline solution in the control (n = 27) group before HIFU treatment which was performed as a linear scan. In both groups, the preselected tissue volumes were destroyed without harming the overlying tissues. Necrosis rate (NR, cm³/s) was used to reflect the ablation efficiency, which was the tissue volume of occurring coagulative necrosis per 1 s HIFU exposure. NR was improved in the experimental group (0.0570 ± 0.0433 vs 0.0120 ± 0.0122, P = 0.0002). Pathological studies confirmed that there were no residual intact targets within the exposed volume. These findings suggested that the introduction of the microbubble agent enhanced HIFU liver destruction.