Ultrasonic contrast agent shell rupture detected by inertial cavitation and rebound signals
Ultrasonic contrast agent shell rupture detected by inertial cavitation and rebound signals
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DOI：
10.1109/tuffc.2006.1588398
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发表时间：
2006-01-01
影响因子：
3.6
通讯作者：
O'Brien, WD
中科院分区：
文献类型：
--
作者：
Ammi, AY;Cleveland, RO;O'Brien, WD
超声造影剂微泡破裂压力阈值的测定在造影剂成像、治疗剂研制、潜在生物效应评价等方面具有重要的应用价值。使用被动空化探测器，这项工作基于单个封装的充气微泡的声发射来评估破裂。在不同的中心频率（0.9、2.8和4.6 MHz）、脉冲持续时间（中心频率的3、5和7个周期）和峰值反射压力（0.07 ~ 5.39 MPa）下，将正弦超声脉冲传输到optionson （TM）弱溶液中。脉冲重复频率为10 Hz。用13mhz， cent - er-frequency换能器检测的信号显示了具有宽带频谱内容的激励后声发射（激励后1至5ps）。观测到的声发射与预期的惯性坍缩的声特征一致，当微泡破裂时，会出现“反弹”，从而产生子泡/自由泡，然后长大并坍缩。检测这些排放物的峰值反射压力阈值随着频率的增加而增加（例如，在0.9、2.8和4.6 MHz频率下，分别为0.53、0.87和0.99 MPa；五个周期脉冲持续时间），并随着脉冲持续时间的增加而降低。在此工作中所鉴定的发射在时间和光谱含量上与激发分离，为微泡壳破裂提供了一种新的测定方法。
Determining the rupture pressure threshold of ultrasound contrast agent microbubbles has significant applications for contrast imaging, development of therapeutic agents, and evaluation of potential bioeffects. Using a passive cavitation detector, this work evaluates rupture based on acoustic emissions from single, encapsulated, gas-filled microbubbles. Sinusoidal ultrasound pulses were transmitted into weak solutions of Optison (TM) at different center frequencies (0.9, 2.8, and 4.6 MHz), pulse durations (three, five, and seven cycles of the center frequencies), and peak rarefactional pressures (0.07 to 5.39 MPa). Pulse repetition frequency was 10 Hz. Signals detected with a 13-MHz, cent er-frequency transducer revealed postexcitation acoustic emissions (between 1 and 5 ps after excitation) with broadband spectral content. The observed acoustic emissions were consistent with the acoustic signature that would be anticipated from inertial collapse followed by "rebounds" when a microbubble ruptures and thus generates daughter/free bubbles that grow and collapse. The peak rarefactional pressure threshold for detection of these emissions increased with frequency (e.g., 0.53, 0.87, and 0.99 MPa for 0.9, 2.8, and 4.6 MHz, respectively; five-cycle pulse duration) and decreased with pulse duration. The emissions identified in this work were separated from the excitation in time and spectral content, and provide a novel determination of microbubble shell rupture.