A method of enhanced shear wave elastography based on Chirp coded excitation

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Ultrasound Technology

Background:

• Shear Wave Elastography (SWE) uses Acoustic Radiation Force (ARF) to characterize soft tissue mechanical properties by analyzing shear wave propagation.
• Current ARF-based SWE faces challenges with weak shear wave generation, in vivo attenuation, and deep-tissue noise, leading to low signal-to-noise ratios.
• Detecting shear waves effectively is crucial for accurate elasticity measurements in various medical applications.

Purpose of the Study:

• To investigate the feasibility of Chirp coded signals for shear wave excitation (Chirp-SWE) in ARF-based shear wave elastography.
• To enhance ARF action and improve shear wave generation and detection compared to conventional methods.
• To evaluate the potential of Chirp-SWE for more accurate and robust soft tissue elastography.

Main Methods:

• Employed Chirp coded excitation of push waveforms to enhance ARF and generate shear waves.
• Conducted comparative experiments using conventional sine long pulses (SWE) and Barker coded signals (Barker-SWE).
• Analyzed theoretical, simulation, elastic phantom, and in vitro liver experiment data to assess performance.

Main Results:

• Chirp-SWE increased excitation energy by approximately 10% compared to conventional SWE and Barker-SWE.
• Elastic phantom experiments showed 30%-50% higher average peak axial particle velocity with Chirp-SWE, indicating more stable shear wave formation.
• Chirp-SWE demonstrated a higher signal-to-noise ratio during elasticity measurements and feasibility in in vitro liver tissue.

Conclusions:

• Chirp coded excitation of push waveforms is feasible and advantageous for improving shear wave elastography.
• Chirp-SWE enhances shear wave generation, stability, and signal-to-noise ratio, overcoming limitations of conventional methods.
• This technique is expected to significantly improve the accuracy and robustness of soft tissue elastography.