A post-compression based ultrasound imaging technique for simultaneous transmit multi-zone focusing.

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Signal Processing

Background:

• Post-compression coded excitation techniques face increasing compression errors and side-lobe levels with lower f-numbers.
• Existing methods struggle with near-field resolution and frame rate limitations.

Purpose of the Study:

• To propose a novel post-compression coded excitation technique with dynamic aperture control to mitigate compression errors.
• To enhance near-field resolution without compromising frame rate.
• To reduce side-lobe levels in ultrasound imaging.

Main Methods:

• Simultaneous transmit multi-zone focusing using two orthogonal complementary Golay codes.
• Transmission of two orthogonal sequences of length 16 toward different focal depths.
• Dynamic focusing and separate compression into short pulses upon reception.
• Acquisition of a single scan line with two transmit foci.

Main Results:

• Range side-lobe levels suppressed below -50 dB with f-number ≥ 3 in simulations (7.5 MHz linear array).
• Experimental verification using a 3.85 MHz curved linear array with f-number of 2.
• Demonstrated improved lateral resolution compared to conventional methods.

Conclusions:

• The proposed dynamic aperture control technique effectively reduces compression errors in post-compression coded excitation.
• The method achieves superior lateral resolution and side-lobe suppression in ultrasound imaging.
• This technique offers a viable solution for enhanced near-field imaging without frame rate reduction.