Harmonic imaging for nonlinear detection of acoustic biomolecules

Area of Science:

• Biomedical Imaging
• Nanotechnology
• Acoustics

Background:

• Gas vesicles (GVs) are promising ultrasound contrast agents for cellular and molecular imaging.
• Current imaging methods for GVs have limitations in sensitivity and require GV destruction.

Purpose of the Study:

• To develop a nondestructive harmonic imaging technique to enhance gas vesicle (GV) detection sensitivity.
• To improve the visualization of cells and tissues using GVs in ultrasound imaging.

Main Methods:

• Developed harmonic cross-propagating wave amplitude modulation (HxAM) imaging.
• Tested HxAM on phantoms with purified GVs, genetically modified cells, and in vivo mouse liver models.
• Analyzed backscattered spectra to understand harmonic imaging advantages.

Main Results:

• HxAM imaging significantly improved GV detection sensitivity compared to traditional methods (p < 0.05).
• Enhanced detection of GV-producing cells by threefold in vitro.
• Achieved over 10 dB improvement in vivo imaging performance and extended imaging depth by 20%.

Conclusions:

• Harmonic imaging, specifically HxAM, offers a highly sensitive and nondestructive method for GV detection.
• This advancement significantly improves ultrasound's capability for molecular and cellular imaging.
• Harmonic signals hold great potential for enhancing GV-based ultrasound imaging applications.