Evaluation of mechanical properties of the shell materials of ultrasound contrast agent microbubbles by high-speed observation of their radial oscillation.

通过高速观察超声造影剂微泡的径向振荡来评估其壳材料的机械性能。

• 批准号: 16300168
• 负责人: KUDO Nobuki
• 金额: $ 8.96万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16300168/
• 关键词: Ultrasound contrast agent; microbubbles; shell; high-speed observation; Diagnostic ultrasound; pressure-dependent attenuation

Improvement of a high-speed observation systemTo improve spatial and temporal resolutions of high-speed observation, the use of an image intensifier with a high-speed camera and the use of an improved optical condenser for a short-arc flash lamp were examined. The use of these devices resulted in a reduction in minimum exposure time from 200 ns to 20 ns at a 40x objective and an increase in maximum framing rate from 4-million to 16-million fps.Development of a system for measurement of pressure-dependent attenuationA system for measurement of attenuation of microbubble suspensions was developed on the basis of results of our previous study on measurement of attenuation of biological tissues. The system uses a wideband pulse of 10 MHz in center frequency as a probing pulse and measures frequency-dependent attenuation in the frequency range of 3 to 14 MHz. Most of the measurement procedure is automated by computer control to achieve high-precision measurements.Evaluation of shell propert … More ies by high-speed observationA microbubble was exposed to a pulse train of increasing pressure amplitudes, and the shell property of the bubble was evaluated from degree of radial change in the oscillating bubble visualized by the high-speed camera. Nine types of microbubbles, seven ultrasound contrast agents, one type of sub-micron bubbles, and one type of plastic-shelled bubbles were examined. The results showed that microbubbles with lipid shells start radial oscillation from several tens of kPa and oscillation amplitude increases with increase in applied pressure and that Palmitic-acid-or albumin-shelled bubbles start radial oscillation when pressure has exceeded a threshold pressure. The difference in pressure-dependent bubble oscillation is consistent with the ultrasound exposure conditions used for the two shell types of bubbles used in clinical practice.Evaluation of shell properties by attenuation measurementAttenuation of the nine types of bubble suspensions was measured using wideband probing pulses of different pressure amplitudes. Since change in radial oscillation under different pressures causes change in attenuation, we also can estimate shell properties from pressure-dependent attenuation of a bubble suspension. The results of measurements showed that each type of bubble has its own characteristics in pressure-dependent attenuation, and these characteristics are consistent with those found by high-speed observation, suggesting that attenuation measurement is also useful to understand the shell properties of microbubbles. Less

高速观测系统的改进为了提高高速观测的空间和时间分辨率，研究了使用带有高速照相机的图像增强器和使用改进的短弧闪光灯的光学聚光器。这些器件的使用使得在40倍物镜下的最小曝光时间从200 ns减少到20 ns，最大帧速率从400万fps增加到1600万fps。在前人研究的基础上，研制了一套微泡悬浮液衰减测量系统，生物组织该系统使用中心频率为10 MHz的宽带脉冲作为探测脉冲，并测量3至14 MHz频率范围内的频率相关衰减。大部分的测量过程都是由计算机控制的自动化过程，以实现高精度的测量。 ...更多信息 将微气泡暴露于增加的压力振幅的脉冲序列，并且根据由高速照相机可视化的振荡气泡中的径向变化程度来评估气泡的壳性质。检查了9种类型的微泡、7种超声造影剂、1种类型的亚微米气泡和1种类型的塑料壳气泡。结果表明，与脂质壳的微泡开始径向振荡从几十kPa和振荡幅度增加，在所施加的压力和棕榈酸或白蛋白壳的气泡开始径向振荡时，压力已超过阈值压力。压力依赖性气泡振荡的差异与临床实践中使用的两种壳型气泡的超声暴露条件一致。通过衰减测量评估壳特性使用不同压力振幅的宽带探测脉冲测量九种类型气泡悬浮液的衰减。由于在不同压力下径向振动的变化引起衰减的变化，我们也可以从气泡悬浮液的压力依赖性衰减来估计壳层性质。测量结果表明，不同类型的气泡具有不同的压力衰减特性，这些特性与高速观测结果一致，表明衰减测量对了解微气泡的壳层特性也是有用的。少

项目成果

A basic study on sonoporation with microbubbles exposed to pulsed ultrasound.

• DOI: 10.1007/s10396-005-0031-5
• 发表时间: 2005-03-01
• 期刊: Journal of medical ultrasonics (2001)
• 作者: Okada, Kengo;Kudo, Nobuki;Yamamoto, Katsuyuki
• 通讯作者: Yamamoto, Katsuyuki

Behavior of microbubbles exposed to pulsed ultrasound and its mechanical effect on a cell

脉冲超声下微泡的行为及其对细胞的机械效应

• 发表时间: 2005
• 期刊: AIP Conference Proceedings 754
• 作者: Khai Jun KEK;宮川 崇拓;Takahiro MIYAKAWA;Khai Jun Kek;Khai Jun Kek;山本克之;Kengo OKADA;Khai Jun KEK;Kengo Okada;Satoshi Yamada;Nobuki Kudo
• 通讯作者: Nobuki Kudo

Novel quantitative assessment of myocardial perfusion by harmonic power Doppler imaging during myocardial contrast echocardiography

• DOI: 10.1136/hrt.2004.035857
• 发表时间: 2005-01
• 期刊: Heart
• 影响因子: 5.7
• 作者: S. Yamada;K. Komuro;T. Mikami;N. Kudo;H. Onozuka;K. Goto;S. Fujii;K. Yamamoto;A. Kitabatake;P. Knaapen;R. B. V. Loon;F. C. Visser