Full-Matrix Phase Shift Migration Method for Transcranial Ultrasonic Imaging.

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Computational Physics

Background:

• Transcranial ultrasound imaging faces challenges due to skull-induced phase aberrations.
• Accurate phase correction is crucial for high-resolution imaging through the skull.

Purpose of the Study:

• To introduce and evaluate a novel spectrum-domain method, full-matrix phase shift migration (FM-PSM), for transcranial ultrasound phase correction and imaging.
• To compare the performance of FM-PSM with the classical ray-tracing delay and sum (DAS) method.

Main Methods:

• FM-PSM was developed as a spectrum-domain method for ultrasound phase correction.
• Simulated data from pseudospectral time-domain method and experimental data from a 3D skull phantom were used for evaluation.
• Performance metrics included resolution, contrast-to-noise ratio (CNR), and computational cost.

Main Results:

• FM-PSM achieved a lateral resolution of 0.22 mm, outperforming ray-tracing DAS (0.24 mm) at 6.25 MHz.
• FM-PSM demonstrated a 17% improvement in CNR (2.14 vs. 1.82) in cylinder imaging experiments.
• Computational cost was reduced from O(J ×M^2×N^2) for DAS to O(J ×M ×N^2) for FM-PSM.

Conclusions:

• FM-PSM is an effective and efficient method for transcranial ultrasound phase correction and imaging.
• The proposed method offers superior resolution and CNR compared to traditional techniques.
• FM-PSM presents a computationally advantageous approach for advanced ultrasonic applications.