Joint Subarray Coherence and Minimum Variance Beamformer for Multitransmission Ultrasound Imaging Modalities.

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Signal Processing

Background:

• Ultrafast ultrasound imaging utilizes multitransmission modalities like plane wave compounding and synthetic aperture imaging.
• Adaptive beamformers, including minimum variance (MV) and coherence factor (CF) based methods, aim to enhance imaging quality but have limitations.
• MV beamformers offer high resolution but lack robustness and are computationally intensive; CF beamformers improve contrast but can over-suppress signals.

Purpose of the Study:

• To propose a novel beamformer for improved imaging quality in multitransmission ultrasound modalities.
• To combine the strengths of MV and CF beamformers while mitigating their respective weaknesses.
• To enhance robustness against noise and parameter errors in ultrasound imaging.

Main Methods:

• A novel beamformer applying MV weighting to both receiving and transmitting beamforming.
• Modification of spatial smoothing for both dimensions to improve robustness.
• Calculation of CF-based weights using MV beamformed output, incorporating the submatrix technique to prevent signal over-suppression.

Main Results:

• The proposed beamformer preserves high resolution (like MV) and high contrast (like CF).
• Demonstrated significant increases in contrast ratio and reduction in full-width at half-maximum compared to traditional compounding methods.
• Improved distinguishability of anatomical structures, such as in vivo human carotid arteries.

Conclusions:

• The novel beamformer achieves superior imaging quality in multitransmission ultrasound by balancing resolution and contrast.
• Enhanced robustness against channel noise and sound velocity errors due to dual-dimension spatial smoothing.
• The method offers a significant advancement for ultrafast ultrasound imaging applications.