Instantaneous phase threshold for reflector detection in ultrasonic images.

Area of Science:

• Ultrasonic Imaging
• Signal Processing
• Medical Imaging

Background:

• Conventional delay-and-sum (DAS) amplitude images in ultrasonic imaging are susceptible to attenuation and artifacts.
• Accurate reflector detection is crucial for diagnostic accuracy in ultrasonic applications.

Purpose of the Study:

• To propose and evaluate a new method for reflector detection in ultrasonic images based on instantaneous phase (IP).
• To assess the performance of the IP-based method in reducing artifacts and improving reflector detectability.

Main Methods:

• Developed an instantaneous phase (IP) image by replacing amplitude with phase information in DAS beamforming.
• Defined an objective threshold level based on signal analysis for creating a two-level image.
• Simulated point spread function and tested the method on phantoms and aluminum plates with artificial defects.

Main Results:

• The IP-based method demonstrated reduced sensitivity to attenuation compared to conventional DAS amplitude images.
• Simulations showed reflector detection at signal-to-noise ratios greater than -29.6 dB.
• Experimental results indicated reduced artifacts and dead zones, with improved reflector detectability and fewer false indications.

Conclusions:

• The proposed instantaneous phase imaging technique offers a robust method for reflector detection in ultrasonic imaging.
• This technique provides objective thresholding and is less sensitive to attenuation, making it a valuable addition to amplitude image analysis.
• It enhances diagnostic capabilities by improving reflector visualization and reducing image interpretation errors.