Impact of target blood vessels angled with acoustic axis on peripheral mode scanning with pulse high intensity focused ultrasound ablation: An experimental study / 中国介入影像与治疗学

ABSTRACT

Objective To explore the impact of different angles between blood vessels and acoustic axis in the target area on pulse high intensity focused ultrasound (PHIFU) peripheral ablation.Methods Thirty New Zealand rabbits were selected,and the thoracic aortas were obtained.Models of tissue mimicking material were used via embedding the rabbit thoracic aorta into the center of the target barrier area.Then the models were divided into 0°,45° and 90° groups according to the angles with the acoustic axis,and the control group was set up as well (each n =10).Under B-ultrasound monitoring,PHIFU peripheral ablation was performed with the same parameters in each group.The temperature was measured during ablation.After ablation,the models were cut step by step for macroscopic and ultrasound observation.The total volumes (V) were calculated and compared,and the target blood vessels were sampled for pathological examination.Results The peripheral region in control group showed strong echo on ultrasound image,while in 0°,45° and 90° group the blood vessels showed low echo accordingly.The maximal temperatures in control group,0°,45° and 90° group was (98.60 ± 5.76) ℃,(98.90 ± 7.09) ℃,(71.10 ± 13.85) ℃ and (70.20 ± 9.14) ℃,respectively.Statisticaldifference was found between control group and 45°,90° group (all P＜0.05).The total volume in control group,0°,45° and 90° group was (40 709.70 ± 3 193.31) mm3,(40 029.02 ± 3 580.17) mm3,(34 562.59 ± 3 883.26) mm3 and (36 737.01± 3 278.68)mm3,respectively,while no statistical difference was found between control group and 0° group (P＞0.05).Pathological examination showed that the elastic fibers fractured partly,and disruption of cell nucleus were observed in 45° and 90° group.Conclusion When the angle between the blood vessel and acoustic axis is 0°,its impact on energy deposition is minimally,while the destruction of the vascular wall becomes stronger when the angle is 45°and 90°.