Parameter effects on arterial vessel sonicated by high-intensity focused ultrasound: anex vivovascular phantom study

Objective.This study is aimed to explore the effects of vascular and sonication parameters onex vivovessel sonicated by high-intensity focused ultrasound.Approach.The vascular phantom embedding the polyolefin tube orex vivovessel was sonicated. The vascular phantom with 1.6 and 3.2 mm tubes was sonicated at three acoustic powers (2.0, 3.5, 5.3 W). The occlusion level of post-sonication tubes was evaluated using ultrasound imaging. The vascular phantom with theex vivoabdominal aorta of rabbit for three flow rates (0, 5, 10 cm s^-1) was sonicated at two acoustic powers (3.5 and 5.3 W). Different distances between focus and posterior wall (2, 4, 6 mm) and cooling times (0 and 10 s) were also evaluated. The diameter of the sonicated vessel was measured by B-mode imaging and microscopic photography. Histological examination was performed for the sonicated vessels.Main results.For the 5 cm s^-1flow rate, the contraction index of vascular diameter (Dc) with 5.3 W and 10 s cooling time at 2 mm distance was 39 ± 9% (n = 9). With the same parameters except for 0 cm s^-1flow rate, theDcwas increased to 45 ± 7% (n = 4). At 3.5 W, theDcwith 5 cm s^-1flow rate was 23 ± 15% (n = 4). The distance and cooling time influenced the lesion along the vessel wall.Significance.This study has demonstrated the flow rate and acoustic power have the great impact on the vessel contraction. Besides, the larger lesion covering the vessel wall would promote the vessel contraction. And thein vivovalidation is required in the future study.