A Resolution Enhancement Technique for Ultrafast Coded Medical Ultrasound

In the quest for faster ultrasound image acquisition rate, low echo signal to noise ratio is often an issue. Binary Phase Shift Keyed (BPSK) Golay codes have been implemented in a large number of imaging methods, and their ability to increase the image quality is already proven. In this paper we propose an improvement of the BPSK modulation, where the effect of the narrow-band ultrasound probe, used for acquisition, is compensated. The optimized excitation signals are implemented in a Plane Wave Compounding (PWC) imaging approach. Simulation and experimental results are presented. Numerical studies show 41% improvement of axial resolution and bandwidth, over the classical BPSK modulated Golay codes. Experimental acquisitions on cyst phantom show an improvement of image resolution of 32%. The method is also compared to classical pulse (small wave packets) emission and 25% boost of resolution is achieved for a 6dB higher echo signal to noise ratio. The experimental results obtained using UlaOp 256 prove the feasibility of the method on a research scanner while the theoretical formulation shows that the optimization of the excitation signals can be applied to any binary sequence and does not depend on the emission/reception beamforming.