The Effect On Large Blood Vasculars On HIFU Beam Axis Close To Focus In Goat Liver Tissues Sonicated By HIFU With Sonovue

High intensity focused ultrasound (HIFU) is a method that use a transducer to focus ultrasound energy in vitro into body and form coagulative necrosis in targeted region in situ,but with no damage to the surrounding tissues , so as to achieve the purpose of resection of the tumor.It have been used in sorts of tumor and non-tumor diseases.The tissues of target region would absorb the energy of the ultrasound wave and be destroyed while the surrounding tissues would not be destroyed. When tissue containing large vascular is treated by HIFU, ultrasonic energy flow away quickly with blood flow, and effective deposition can not form in the target area. In recent years, ultrasound microbubble agent is considered as a synergistic agent to increase the efficiency of HIFU. When ultrasound contrast agent is applied in HIFU treatment, on one hand, microbubble increases cavitation nucleus in tissues,that will help to increase the deposition of ultrasonic energy, on the other hand, vasculars on HIFU beam axis close to focus contain certain concentration of ultrasound contrast agent, whether the agent will increase the deposition of ultrasonic energy on the vascular, causing damage, that is a safety problem.In this research, a new-styled ultrasound microbubble SonoVue was chosed for the goat liver tissue ablation combined with HIFU, to evaluate the damage formation in target area containing larger vessels, and evaluate damage formation of blood vasculars on HIFU beam axis close to focus.Objective1.To study the formation of lesions caused by HIFU with SonoVue, in liver tissues on HIFU beam axis close to focus containing blood vessels,so as to study the enhancement effect of ultrasound microbubble agent for HIFU.2.To investigate the security of blood vessels on HIFU beam axis close to focus sonicated by HIFU combined with ultrasound microbubble agent.Methods1.Ultrasound diagnosis was used for information collection, to find the goat hepatic blood vessels with diameter approximately 3mm.HIFU irradiation was below, on and above the vessels respectively, power is 250W, to scan by straight line, of which the length is 10mm, the speed is 3mm /s, 9 times. In the experimental group,0.03 ml/kg SonoVue was injected into the goat before HIFU irradiation, and the control group released saline. Calculation of coagulative necrosis volume and energy efficiency factor,to compare the difference of coagulative necrosis volume and energy efficiency factor between groups with and without SonoVue, and to evaluation enhancement of the efficiency of HIFU combined with SonoVue ablating target areas containing large blood vasculars on HIFU beam axis close to focus.2.Ultrasound diagnosis was used for information collection, to find the goat hepatic blood vessels with diameter approximately 3mm.HIFU focus was below, on and above the vasculars respectively, power is 250W ,to scan by straight line, of which the length is 10mm, the speed is 3mm /s, 9 times. In the experimental group,0.03 ml/kg SonoVue was injected into the goat before HIFU irradiation, and the control group released saline. The goats were killed 24h after HIFU irradiation, perfusion of Evans blue, HE staining, and Victoria's blue and Ponceau's staining were used to observe the vascular injury.Results1.When the depth was 30mm,and the target regions caotained large blood vessels on HIFU beam axis close to focus, HIFU with SonoVue could form lesions effectively.When the vasculars were above the HIFU focus, the coagulative necrosis volume of experimental group and control group were 1193.20 cm3 and 91.59 cm3 respectively,and energy efficiency factor were 4.40 J/mm3 and 59.72 J/mm3 respectively. When the vasculars were in the HIFU focus, the coagulative necrosis volume of experimental group and control group were 642.92 cm3 and 211.95 cm3 respectively,and energy efficiency factor were 8.18 J/mm3 and 24.88 J/mm3 respectively. When the vasculars were below the HIFU focus, the coagulative necrosis volume of experimental group and control group were 706.50 cm3 and 379.16 cm3 respectively,and energy efficiency factor were 7.17 J/mm3 and 14.09 J/mm3 respectively.There was difference of necrosis volumes between lesions with and without SonoVue,and the difference was significant(P<0.05).2. The perfusion of Evans dye showed that the permeability of the vascular on HIFU beam axis close to focus had no change, HE staining and VP staining(Victoria's blue and Ponceau's staining) of tissue section showed that vasculars on the acoustic axis nearby focus were not damaged in both with and without SonoVue groups.Conclusions1.When the target tissues contain large vasculars on HIFU beam axis close to focus, SonoVue can increases the efficacy of HIFU, and form lesions effectively.2.HIFU combined with SonoVue will not damage vasculars on HIFU beam axis close to focus.