Tissue ultrasound imaging based on wavelet correlation analysis and pulse-inversion technique.

Area of Science:

• Ultrasound imaging
• Medical physics
• Signal processing

Background:

• Pulse-inversion-based tissue harmonic imaging (PIHI) reduces harmonic leakage but is susceptible to motion artifacts, limiting spatial resolution and contrast.
• Existing methods struggle with motion sensitivity and suboptimal image quality.

Purpose of the Study:

• To enhance ultrasound image quality using a novel pulse-inversion-based tissue harmonic imaging technique.
• To address motion artifacts and improve spatial resolution and contrast in ultrasound imaging.

Main Methods:

• Continuous wavelet transform was employed to correlate mother wavelets with received ultrasound echoes.
• A novel 'tissue wavelet' was designed using the Khokhlov-Zabolotskaya-Kuznetsov (KZK) wave equation for improved correlation.
• Radio frequency data were acquired using an Ultrasonix SonixTouch system and tested on phantoms and human tissues.

Main Results:

• The proposed technique demonstrated an average 49.52% improvement in lateral spatial resolution compared to standard PIHI.
• Contrast ratio (CR) and contrast-to-noise ratio (CNR) showed significant increases of 5.55 dB and 1.40 dB, respectively.
• The custom 'tissue wavelet' outperformed standard Mexh and Morl wavelets in all tested metrics.

Conclusions:

• The developed pulse-inversion-based technique effectively enhances ultrasound image quality.
• Significant improvements in lateral spatial resolution, CR, and CNR were achieved.
• The novel 'tissue wavelet' offers superior performance for ultrasound tissue harmonic imaging.