Extended velocity range in color flow imaging using parallel receive beamforming

In this work we investigate how advances in parallel receive beamforming (PRB) can be utilized to increase the velocity range in color flow imaging, through the acquisition and processing of longer slow-time ensembles (>;20) at high pulse repetition frequencies. Using unfocused transmit beams and a 16xPRB setup, vascular imaging examples of thyroid, carotid, and peripheral vessels were achieved with 5-10 times increase in velocity range. It is also shown how the approach substantially reduces the velocity bias associated with time-variant clutter filters, yielding more consistent velocity estimates and less flashing artifacts. The approach has particular advantages when imaging low flow or complex vessel architectures, but may also be a step towards a more quantitative CFI modality for a larger range of imaging scenarios.