Bubble-based acoustic radiation force elasticity imaging
Bubble-based acoustic radiation force elasticity imaging
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DOI：
10.1109/tuffc.2005.1504019
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发表时间：
2005-06-01
影响因子：
3.6
通讯作者：
O'Donnell, M
中科院分区：
文献类型：
--
作者：
Erpelding, TN;Hollman, KW;O'Donnell, M
将声辐射力作用于激光诱导光学击穿（LIOB）产生的气泡，研究其周围介质的粘弹性。在这项研究中，飞秒激光脉冲聚焦在不同浓度的明胶幻影的体积形成气泡。一种双元件共焦超声换能器在单个气泡上产生声辐射力，同时监测它们在粘弹性介质内的位移。由外部元件以1.5 MHz施加了不同持续时间的短纯音推动。内部元件在激发爆发之前、期间和之后接收7.44 MHz的脉冲回波记录，并且离线执行互相关处理以监测气泡位置。最大气泡位移与不同凝胶体模的杨氏模量成反比，在杨氏模量为1.7 kPa的凝胶体模中，最大气泡位移超过200 pm。气泡位移与所施加的声辐射力和位移成比例;可以归一化以校正气泡尺寸的差异。气泡位移曲线的指数时间常数与气泡半径无关，并随周围介质的杨氏模量而减小。这些结果表明，基于气泡的声辐射力的方法来测量组织的粘弹性的潜力。
Acoustic radiation force is applied to bubbles generated by laser-induced optical breakdown (LIOB) to study viscoelastic properties of the surrounding medium. In this investigation, femtosecond laser pulses are focused in the volume of gelatin phantoms of different concentrations to form bubbles. A two-element confocal ultrasonic transducer generates acoustic radiation force on individual bubbles while monitoring their displacement within a viscoelastic medium. Tone burst pushes of varying duration have been applied by the outer element at 1.5 MHz. The inner element receives pulse-echo recordings at 7.44 MHz before, during, and after the excitation bursts, and cross-correlation processing is performed offline to monitor bubble position. Maximum bubble displacements are inversely related to the Young's moduli for different gel phantoms, with a maximum bubble displacement of over 200 pm in a gel phantom with a Young's modulus of 1.7 kPa. Bubble displacements scale with the applied acoustic radiation force and displacements; can be normalized to correct for differences in bubble size. Exponential time constants for bubble displacement curves are independent of bubble radius and follow a decreasing trend with the Young's modulus of the surrounding medium. These results demonstrate the potential for bubble-based acoustic radiation force methods to measure tissue viscoelastic properties.