The delayed onset of subharmonic and ultraharmonic emissions from a phospholipid-shelled microbubble contrast agent.
The delayed onset of subharmonic and ultraharmonic emissions from a phospholipid-shelled microbubble contrast agent.
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DOI：
10.1016/j.ultrasmedbio.2014.01.002
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发表时间：
2014-04
影响因子：
2.9
通讯作者：
Doyley, Marvin M.
中科院分区：
文献类型：
--
作者：
Shekhar, Himanshu;Awuor, Ivy;Thomas, Keri;Rychak, Joshua J.;Doyley, Marvin M.
关键词：
表征微泡造影剂的非线性响应对于它们在成像和治疗中的有效使用是重要的。在本文中，我们报告的次谐波和超谐波响应的脂质壳微泡造影剂表现出很强的时间依赖性。我们表征了来自Targestar-P®微泡（Targeson Inc.，San Diego，CA，USA），在10 MHz激发频率下周期性地持续60分钟。结果显示，在制剂制备5-10分钟后，次谐波和超谐波响应显著增加（接近12-15和5-8 dB）。然而，基波和谐波响应在此期间几乎保持不变。在接下来的50分钟内，次谐波、基波、超谐波和谐波响应稳定下降2-5 dB。代理的非线性行为的时间变化似乎主要是通过微泡壳的气体交换介导的;排除了基于温度和先前声激发的机制。此外，通过静态扩散，试剂尺寸分布没有可测量的变化。我们设想，这些发现将有助于获得可重复的测量从代理表征，非线性成像和流体压力传感。这些发现也表明了通过仔细设计超声造影剂来改善非线性成像的可能性。
Characterizing the nonlinear response of microbubble contrast agents is important for their efficacious use in imaging and therapy. In this paper, we report that the subharmonic and ultraharmonic response of lipid-shelled microbubble contrast agents exhibits a strong temporal dependence. We characterized nonlinear emissions from Targestar-P® microbubbles (Targeson Inc., San Diego, CA, USA) periodically for 60 minutes, at 10 MHz excitation frequency. The results revealed a considerable increase in the subharmonic and ultraharmonic response (nearly 12–15 and 5–8 dB) after 5–10 minutes of agent preparation. However, the fundamental and the harmonic response remained almost unchanged in this period. During the next 50 minutes, the subharmonic, fundamental, ultraharmonic, and harmonic responses decreased steadily by 2–5 dB. The temporal changes in the nonlinear behavior of the agent appeared to be primarily mediated by gas-exchange through the microbubble shell; temperature and prior acoustic excitation based mechanisms were ruled out. Further, there was no measurable change in the agent size distribution by static diffusion. We envisage that these findings will help obtain reproducible measurements from agent characterization, nonlinear imaging, and fluid-pressure sensing. These findings also suggest the possibility for improving nonlinear imaging by careful design of ultrasound contrast agents.
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影响因子：
2.4
作者：
Haworth, Kevin J.;Mast, T. Douglas;Holland, Christy K.
通讯作者：
Holland, Christy K.
影响因子：
2.3
作者：
Halldorsdottir VG;Dave JK;Leodore LM;Eisenbrey JR;Park S;Hall AL;Thomenius K;Forsberg F
通讯作者：
Forsberg F
DOI：
10.1109/tuffc.2005.1397351
发表时间：
2005-01-01
影响因子：
3.6
作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
4.2
作者：
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通讯作者：
Goldberg, BB