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首页> 外文期刊>IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control >Observation of contrast agent response to chirp insonation with a simultaneous optical-acoustical system
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Observation of contrast agent response to chirp insonation with a simultaneous optical-acoustical system

机译：同时光学-声学系统观察造影剂对chi声的响应

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Rayleigh-Plesset analysis, ultra-high speed photography, and single bubble acoustical recordings previously were applied independently to characterize the radial oscillation and resulting echoes from a microbubble in response to an ultrasonic pulse. In addition, high-speed photography has shown that microbubbles are destroyed over a single pulse or pulse train by diffusion and fragmentation. In order to develop a single model to characterize microbubble echoes based on oscillatory and destructive characteristics, an optical-acoustical system was developed to simultaneously record the optical image and backscattered echo from each microbubble. Combined observation provides the opportunity to compare predictions for oscillation and echoes with experimental results and identify discrepancies due to diffusion or fragmentation. Optimization of agents and insonating pulse parameters may be facilitated with this system. The mean correlation of the predicted and experimental radius-time curves and echoes exceeds 0.7 for the parameters studied here. An important application of this new system is to record and analyze microbubble response to a long pulse in which diffusion is shown to occur over the pulse duration. The microbubble response to an increasing or decreasing chirp is evaluated using this new tool. For chirp insonation beginning with the lower center frequency, low-frequency modulation of the oscillation envelope was obvious. However, low-frequency modulation was not observed in the radial oscillation produced by decreasing chirp insonation. Comparison of the echoes from similar sized microbubbles following increasing and decreasing chirp insonation demonstrated that the echoes were not time-reversed replicas. Using a transmission pressure of 620 kPa, the -6 dB echo length was 0.9 and 1.1 /spl mu/s for increasing and decreasing chirp insonation, respectively (P = 0.02). The mean power in the low-frequency portion of the echoes was 8 (mV)/sup 2/ and 13 (mV)/sup 2/ for increasing and decreasing chirp insonation, respectively (P = 0.01).
机译：以前分别应用了Rayleigh-Plesset分析，超高速摄影和单个气泡声学记录来表征径向振动以及响应超声脉冲而产生的微气泡回波。此外，高速摄影表明，微气泡在单个脉冲或脉冲序列上被扩散和破碎破坏。为了开发基于振动和破坏特性的表征微气泡回波的单一模型，开发了一种光学声学系统，用于同时记录每个微气泡的光学图像和反向散射回波。组合观测提供了将振荡和回声的预测与实验结果进行比较，并确定由于扩散或断裂而引起的差异的机会。该系统可以促进药剂和声脉冲参数的优化。对于此处研究的参数，预测和实验的半径时间曲线和回波的平均相关性超过0.7。该新系统的重要应用是记录和分析对长脉冲的微气泡响应，其中显示出在脉冲持续时间内发生了扩散。使用此新工具可以评估微气泡对增大或减小的线性调频脉冲的响应。对于从较低中心频率开始的chi声，振荡包络的低频调制是明显的。但是，在降低线性调频声产生的径向振动中未观察到低频调制。线性调频声增加和减小后，来自类似大小的微气泡的回声的比较表明，回声不是时间反转的复制品。使用620 kPa的传输压力，-6 dB回波长度分别为0.9和1.1 / spl mu / s，分别用于增加和减少线性调频声（P = 0.02）。回波的低频部分的平均功率分别为8（mV）/ sup 2 /和13（mV）/ sup 2 /，分别用于增大和减小线性调频声（P = 0.01）。

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