Precision improvement of magneto-acousto-electrical imaging based on the excitation of single Sinusoid-Golay coded pulse

Based on imaging requirements for biological tissues with low-level electrical conductivities, the single Sinusoid-Golay coded pulse excitation is introduced to enhance the signal-to-noise ratio (SNR) and the positioning accuracy of magneto-acousto-electrical (MAE) signals, resulting in the improved precision of MAE imaging. Firstly, the formula of the detected MAE signal is derived for the single-excitation of a Sinusoid-Golay coded pulse with the consideration of the radiation pattern of actual transducers. The MAE measurement of the dual-excitation is realized by introducing the excitation conversion factor and the autocorrelation calculation. The main lobe amplitude enhancement by 2N times is demonstrated in theory for the N-bit Sinusoid-Golay coded pulse excitation with the favorable capabilities of pulse compression and noise suppression. Then, numerical studies for MAE signals are conducted for a layered gel model under the SNR of 5 dB. The pulse compression and suppression of side-lobes for decoded MAE signals are accomplished by the matched filter and the wave superposition with improved accuracies of boundary positions and conductivity gradients. Finally, compared with the one-cycle sinusoidal excitation, the SNR improvement of about 6.5 dB is proved by the experimental measurement of MAE signals for a three-layer gel model with the 16-bit Sinusoid-Golay coded pulse excitation. The image of tissue boundaries is reconstructed accurately in terms of amplitude and polarity of conductivity variations. This study provides an optimized fast imaging technology for the detection of early tissue lesions based on the difference of electrical properties.