Although microbubble contrast agents are believed to respond differently under different driving-pressure amplitudes, few studies have been performed to extensively study the pressure-dependence of their properties. In this paper, attenuation coefficients of two contrast agents (Optison™ and Definity™) were measured under different driving-pressure amplitudes using a narrowband incident pulse. The attenuation of both contrast agents was found to increase with increasing driving pressure. Simulations using the Rayleigh, Plesset, Noltingk, Neppiras, Poritsky (RPNNP) equation were performed to study this behavior. Simulation results show that significant harmonic generation at high driving-pressure amplitudes contributes to the higher attenuation. Other possible explanations for this behavior were also examined. Attenuation coefficients of two contrast agents were also measured using a broadband method. The results showed great inconsistency when the center frequency of the incident broadband pulse was changed, indicating that broadband techniques may not be suitable for contrast-agent attenuation measurements.
|Number of pages
|Ultrasound in Medicine and Biology
|Published - Aug 2002
Bibliographical noteFunding Information:
The authors thank Gary Frank and Prof. Ernest Madsen for their support with the experiment apparatus and valuable discussions. The authors also thank Dupont and Mallinckrodt for providing contrast agents. This work was supported in part by NIH (grant R01CA39224).
- Attenuation measurement
- Broadband measurement
- Contrast agent
- Narrowband measurement
- Pressure dependence
ASJC Scopus subject areas
- Radiological and Ultrasound Technology
- Acoustics and Ultrasonics