An Investigation of Material and Acoustic Properties of Ultrasound Contrast Agents for Non-Invasive Pressure Measurement

Ultrasound imaging is a safe and accessible imaging method, and its utility can be enhanced with micron-sized gas bubbles, known as microbubbles, as contrast agents. This dissertation focuses on characterizing the material and acoustic properties of microbubbles for their application in novel ultrasound imaging applications including a non-invasive pressure measurement technique, Subharmonic Aided Pressure Estimation (SHAPE). First, we explore the influence of encapsulation chemical composition, particularly lipid and polyethylene glycol (PEG) ratios, on material properties, stability, and resonance frequency of microbubbles through acoustic attenuation measurements and employing bubble dynamics models. Our findings reveal the impact of PEG chain configuration on the encapsulation elasticity and bubbles resonance frequency. Furthermore, we use acoustic backscatter measurements to investigate the acoustic behavior of microbubbles under varying ambient pressure conditions, to characterize the correlation between ambient pressure and subharmonic response amplitude over a wide range of ultrasound excitation amplitude and frequency, crucial for SHAPE. Additionally, we scrutinize commercially available contrast agent, SonoVue, uncovering their unique acoustic response and sensitivities to ambient pressure. By modifying the gas core of SonoVue, we probe the underlying mechanism in subharmonic response generation and its sensitivity to ambient pressure. This research advances our understanding of microbubble acoustics and paves the way for innovative applications in ultrasound imaging for biomedical diagnostics and beyond.

Author

• Hassanzadeh Azami, Roozbeh

Language

• English

Keyword

• Biomedical Ultrasound
• Contrast Agents
• Subharmonic Aided Pressure Estimation
• Lipid micro-Bubbles
• Acoustics

Date created

• 2024

Type of Work

• Dissertation

License

• All rights reserved

Rights statement

• In Copyright

GW Unit

• Mechanical & Aerospace Engineering

Degree

• Ph.D.

Advisor

• Sarkar, Kausik

Committee Member(s)

• Keidar, Michael
• Rau, Matthew
• Zhang, Lijie Grace
• Eisenbrey, John

Persistent URL

•  https://scholarspace.library.gwu.edu/etd/t148fj09f