Angular coherence in ultrasound imaging: Theory and applications

Area of Science:

• Medical physics
• Ultrasound imaging
• Acoustics

Background:

• Plane-wave transmissions are popular in synthetic transmit aperture (coherent compounding) ultrasonic imaging.
• The coherence properties of backscattered signals with multi-angle plane-wave transmits are not well understood.
• This lack of understanding may affect various advanced ultrasonic imaging techniques.

Purpose of the Study:

• To introduce a theoretical framework for analyzing the coherence properties of backscattered signals in ultrasound.
• To establish angular coherence theory for medical ultrasound imaging.
• To explore applications of this theory in beamforming and parameter estimation.

Main Methods:

• Development of angular coherence theory, relating signal correlation to receive aperture characteristics.
• Validation of the theory using simulations and experimental data on speckle targets.
• Proposal and comparison of a novel short-lag angular coherence beamformer against existing methods.

Main Results:

• The angular coherence theory establishes a Fourier transform relationship between signal correlation and receive aperture autocorrelation.
• The theory is experimentally validated, demonstrating its applicability.
• The proposed short-lag angular coherence beamformer shows potential for improved performance.

Conclusions:

• Angular coherence theory provides a robust framework for understanding signal coherence in plane-wave ultrasound.
• This theory facilitates the development of advanced beamforming strategies.
• The theory has practical applications in phase shift and speed of sound estimation in ultrasound imaging.