Pulse-Inversion Subharmonic Ultrafast Active Cavitation Imaging in Tissue Using Fast Eigenspace-Based Adaptive...

Area of Science:

• Medical Imaging
• Acoustic Cavitation
• Signal Processing

Background:

• Pulse-inversion subharmonic (PISH) imaging visualizes pure cavitation bubbles, excluding tissue signals.
• Ultrafast active cavitation imaging (UACI) monitors cavitation bubble activity but has limited resolution and cavitation-to-tissue ratio (CTR).
• Eigenspace-based (ESB) adaptive beamforming can improve UACI resolution and CTR but is computationally intensive and difficult for real-time implementation.

Purpose of the Study:

• To develop a novel PISH-UACI method addressing real-time implementation and resolution degradation.
• To introduce fast ESB (F-ESB) beamforming for reduced computational complexity and improved ESB performance.
• To enhance image resolution using cavitation deconvolution for nonlinear signals.

Main Methods:

• Developed a fast ESB (F-ESB) beamforming technique using principal component analysis for dimensionality reduction.
• Implemented cavitation deconvolution with a modified convolution model and compressive deconvolution to recover resolution.
• Combined F-ESB beamforming and cavitation deconvolution within the PISH-UACI framework.

Main Results:

• The proposed F-ESB PISH-UACI method reduced computational complexity by 99% compared to the original ESB method.
• Axial resolution gain increased by 3 times, and the cavitation-to-tissue ratio (CTR) improved by 2 dB.
• Simulations and in vitro experiments validated the effectiveness of the proposed method.

Conclusions:

• The novel F-ESB PISH-UACI method offers a computationally efficient solution for real-time cavitation imaging.
• The combined approach significantly improves image resolution and CTR for monitoring cavitation bubbles in tissue.
• This technique provides satisfactory performance for tissue erosion monitoring using cavitation bubbles.