Department of Biomedical Imaging and Radiological Sciences, School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan.
Med Eng Phys. 2012 Apr;34(3):313-7. doi: 10.1016/j.medengphy.2011.07.021. Epub 2011 Aug 11.
The purpose of this study is to investigate the dose-dependent effects of ultrasound contrast agent (UCA) on the changes of peak systolic velocity (PSV) and pulsatility index (PI) in the arteries of 24 male Sprague-Dawley rats. The rats were sonicated with 1.0-MHz pulsed high-intensity focused ultrasound (HIFU) at two acoustic powers, 15 W and 30 W, with UCA present at four concentrations (0, 150, 300, and 450 μL/kg). Ultrasound imaging was used to localize and to monitor the pulsed-HIFU exposure. The mean PSV of blood flow, as measured by Doppler ultrasound imaging, increased immediately in the arteries where UCA has been administrated at all four doses after pulsed-HIFU at 15 W. However, the normalized PSV change decreased with each injected dose of UCA at 30 W. Furthermore, the normalized pulsatility index changes increased as the injected dose of UCA increased at two acoustic powers. No obvious changes were found in terms of histological structures and temperature rise at the vessel wall. Our results demonstrated that the response of the artery to pulsed-HIFU was dependent on UCA dose at the same acoustic power. The value of normalized PSV change was minimal and the normalized PI change reached a maximum when the UCA dose was at the highest dose of UCA (450 μL/kg) with the two acoustic powers.
本研究旨在探讨超声造影剂（UCA）在两种声功率（15 W 和 30 W）下对 24 只雄性 Sprague-Dawley 大鼠动脉收缩期峰值流速（PSV）和搏动指数（PI）变化的剂量依赖性影响。用 1.0MHz 脉冲高强度聚焦超声（HIFU）对大鼠进行超声处理，UCA 浓度分别为 0、150、300 和 450μL/kg。超声成像用于定位和监测脉冲-HIFU 暴露。通过多普勒超声成像测量的血流平均 PSV，在 15 W 脉冲-HIFU 后，所有四个剂量的 UCA 注入动脉后立即增加。然而，在 30 W 时，随着 UCA 注射剂量的增加，归一化 PSV 变化减小。此外，在两种声功率下，随着 UCA 注射剂量的增加，归一化搏动指数变化增加。在血管壁的组织结构和温升方面没有发现明显的变化。我们的结果表明，在相同声功率下，动脉对脉冲-HIFU 的反应取决于 UCA 剂量。在两种声功率下，当 UCA 剂量达到最高剂量（450μL/kg）时，归一化 PSV 变化值最小，归一化 PI 变化值最大。
