Nonlinear ultrasonic imaging in pulse-echo mode using Westervelt equation: a preliminary research.

Area of Science:

• Medical Imaging
• Acoustics
• Biophysics

Background:

• Acoustic nonlinear parameter (β) is crucial for tissue characterization.
• Nonlinear imaging offers improved spatial and contrast resolution in diagnostic ultrasound.
• Existing methods face challenges with scattering, diffraction, and linear attenuation.

Purpose of the Study:

• To introduce a novel nonlinear imaging method for diagnostic ultrasound.
• To enhance tissue characterization using acoustic nonlinearity.
• To validate the method's ability to map the spatial distribution of the B/A parameter.

Main Methods:

• Derivation of a nonlinear imaging method from the nonlinear wave equation.
• Assumption of a Gaussian-form solution for wave propagation.
• Application in pulse-echo mode using two-pulse transmission.
• Elimination of scattering, diffraction, and linear attenuation effects.
• Validation using a nonlinear simulator and simulated results.

Main Results:

• The proposed method successfully isolates nonlinear effects.
• Simulated images demonstrate the method's capability to eliminate confounding factors.
• The technique accurately depicts the spatial distribution of the B/A parameter in the medium.

Conclusions:

• The developed nonlinear imaging method provides a robust approach for tissue characterization.
• This technique offers improved accuracy in assessing acoustic nonlinearity.
• It holds potential for advancing diagnostic ultrasound applications.