A study on the reconstruction of moderate contrast targets using the distorted born iterative method

Area of Science:

• Medical Imaging
• Acoustics
• Computational Physics

Background:

• Ultrasound tomography for sound speed and attenuation imaging faces convergence challenges with moderate contrast targets.
• Existing methods struggle to accurately reconstruct targets exhibiting slight variations in sound speed.

Purpose of the Study:

• To develop and validate a novel multiple frequency, distorted Born iterative method (DBIM) for stable ultrasound tomographic reconstruction.
• To address convergence issues in imaging targets with moderate speed of sound contrast.
• To implement and test a new regularization scheme for improved inversion stability.

Main Methods:

• Utilized a multiple frequency distorted Born iterative method (DBIM) with fixed receiver positions.
• Developed a novel regularization scheme involving Rayleigh quotient iteration and residual error-based relaxation.
• Validated the method through simulations exploring variable density effects and experimental measurements.

Main Results:

• Successfully stabilized DBIM for both full and partial receiver angular coverage without significant spatial resolution loss.
• Achieved accurate speed of sound profile reconstructions for saline-filled balloons in water.
• Demonstrated a mean squared error of 1.1% for reconstructions with 16.4% sound speed contrast.

Conclusions:

• The multiple frequency DBIM offers a stable and accurate solution for ultrasound tomographic reconstruction of sound speed.
• The developed regularization scheme effectively overcomes convergence problems in moderate contrast scenarios.
• Experimental validation confirms the method's capability in real-world imaging applications.