Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
Shenzhen Key Laboratory of Ultrasound Imaging and Therapy, Shenzhen 518055, China.
Sensors (Basel). 2018 Nov 22;18(12):4083. doi: 10.3390/s18124083.
Microbubbles are considered a promising tool for noninvasive estimation of local blood pressure. It is reported that the subharmonic scattering amplitude of microbubbles decreases by 9 to 12 dB when immersed in the media under an ambient pressure variation from 0 to 180 mmHg. However, the pressure sensitivity still needs to be improved to satisfy clinical diagnostic requirements. Here, we investigated the effects of acoustic parameters on the pressure sensitivity of microbubbles through measuring the acoustic attenuation and scattering properties of commercially available SonoVue microbubbles. Our results showed that the first harmonic, subharmonic, and ultraharmonic amplitudes of microbubbles were reduced by 6.6 dB, 10.9 dB, and 9.3 dB at 0.225 mechanical index (MI), 4.6 dB, 19.8 dB, and 12.3 dB at 0.25 MI, and 18.5 dB, 17.6 dB, and 12.6 dB at 0.3 MI, respectively, when the ambient pressure increased from 0 to 180 mmHg. Our finding revealed that a moderate MI (0.25⁻0.4) exciting microbubbles could significantly improve their sensitivities to detect ambient pressure.
微泡被认为是一种很有前途的无创估计局部血压的工具。据报道，当微泡在环境压力从 0 到 180mmHg 的变化下浸泡在介质中时，其亚谐波散射幅度降低了 9 到 12dB。然而，为了满足临床诊断的要求，其压力灵敏度仍需要提高。在这里，我们通过测量商用 SonoVue 微泡的声衰减和散射特性，研究了声参数对微泡压力灵敏度的影响。结果表明，当环境压力从 0 增加到 180mmHg 时，微泡的基频、次谐波和超谐波幅度分别降低了 6.6dB、10.9dB 和 9.3dB（0.225 机械指数[MI]）、4.6dB、19.8dB 和 12.3dB（0.25MI）以及 18.5dB、17.6dB 和 12.6dB（0.3MI）。我们的发现表明，适度的 MI（0.25-0.4）激发微泡可以显著提高其检测环境压力的灵敏度。
