K3. Synthetic transmit aperture medical ultrasound imaging

In this paper we use real data to test the utility of synthetic aperture (SA) ultrasound imaging to overcome the limitation of conventional ultrasound image which include decreasing the frame rate and single transmit focusing. The images are reconstructed by using different types of transmission and used to test the effect of signal to noise ratio (SNR). The results show that increasing the number of aperture elements improves the SNR. This means that overcoming the problem of low SNR can be achieved by replacing single element transmission by simultaneous excitation of multi-element sub-apertures. We designed 24-tap FIR Hilbert transformed with acceptable normalized RMSE with the analytical form of the signal. The images were reconstructed with and without the FIR Hilbert transform filter. Synthetic aperture imaging is shown to have potential for alleviating the problem of frame rate limitation and single transmit focusing. On the other hand, it is also shown to have several problems associated with its practical implementation in terms of penetration depth, flow estimation, and implementation.