Polydisperse Versus Monodisperse Microbubbles: A Simulation Study for Contrast-Enhanced Ultrasound Imaging

Area of Science:

• Medical Imaging
• Acoustics
• Biophysics

Background:

• Contrast-enhanced ultrasound (CEUS) utilizes microbubbles (MBs) for enhanced vascular visualization and organ perfusion.
• Novel monodisperse MB formulations are being developed to improve upon traditional polydisperse MBs for more consistent imaging outcomes.

Purpose of the Study:

• To investigate the contrast enhancement properties of various-sized monodisperse MBs.
• To analyze the influence of monodisperse MBs on non-linear imaging artifacts in CEUS.
• To compare the performance of monodisperse versus polydisperse MBs in simulated ultrasound environments.

Main Methods:

• Numerical simulations using the iterative non-linear contrast source (INCS) method were employed.
• The INCS method realistically simulated ultrasound propagation in both monodisperse and polydisperse MB populations.
• Individual bubble properties and multiple scattering effects were considered in the simulations.

Main Results:

• Scattering from resonant monodisperse MBs was 11.8 dB stronger than from polydisperse MBs.
• Non-linear imaging artifacts downstream of monodisperse MBs were 19.4 dB stronger compared to polydisperse suspensions.
• Monodisperse MBs demonstrated a higher signal-to-noise ratio.

Conclusions:

• Monodisperse MBs are more effective contrast agents in CEUS, particularly at resonance.
• Enhanced non-linear wave propagation artifacts occur with monodisperse MBs.
• These artifacts can lead to misclassification of MBs as tissue in CEUS imaging.