Real-time multi-line vector Doppler system based on layered array beams

Conventional ultrasound (US) diagnosis of cardiovascular diseases adopts spectral Doppler methods to estimate the velocity of blood in vessels. We recently proposed a real-time method that estimates the flow speed vectors along 8 parallel lines of interest, arbitrarily distributed over the region of interest. It employs the transmission of plane waves that, however, inefficiently spreads the energy over a wide region, thus reducing the contrast of the investigated Doppler lines. In this work, we assess at which extent the features of layered array beams, namely limited diffraction beams composed of parallel beams of equal thickness, could be beneficial to improve the performance of the real-time multi-line vector Doppler system, which is implemented in real-time on the new ULA OP 256 scanner. Here, we show that layered array beams allow reducing by about 2dB possible artifacts in the vessel lumen. In addition, in-vitro tests demonstrate that the velocity vectors are properly reconstructed in different conditions with a relative error lower than 10%. Finally, an example of in-vivo exam is shown, demonstrating the effectiveness of the proposed method.