Correction of phase aberrations for sectored annular array ultrasound transducers

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Biomedical Engineering

Background:

• Phase aberrations in ultrasound imaging arise from inhomogeneous acoustic velocities within tissues.
• These distortions degrade image quality, limiting diagnostic accuracy in medical ultrasound.
• Sectored annular array systems are susceptible to phase aberrations, necessitating correction methods.

Purpose of the Study:

• To investigate two methods for correcting unknown phase aberrations in sectored annular array ultrasound systems.
• To compare the effectiveness of cross correlation and speckle brightness maximization techniques.
• To assess the potential for improving clinical ultrasound image quality.

Main Methods:

• Adaptations of cross correlation and speckle brightness maximization techniques were employed.
• Phase shifts were introduced at the beamformer stage of a sectored annular array transducer.
• Software models and a computer-controlled automated scanning system were used for investigation.
• A 65-element sectored annular array was simulated using a rotating 5-element transducer.
• Tissue-equivalent materials formed a double-layer aberrating medium simulating rectus abdominis muscle in vivo.

Main Results:

• The cross correlation technique increased anechoic region contrast from 0.34 +/- 0.08 to 0.48 +/- 0.06.
• The speckle brightness maximization method improved contrast to 0.62 +/- 0.05.
• Both methods demonstrated effectiveness in correcting phase distortions in simulated tissue phantoms.

Conclusions:

• The speckle brightness maximization technique offers superior performance in enhancing ultrasound image contrast.
• These phase aberration correction methods show significant potential for improving image quality in clinical ultrasound systems.
• Further development could lead to enhanced diagnostic capabilities in medical ultrasound applications.