Reducing color flow artifacts caused by parallel beamforming

In color flow imaging for medical diagnosis, the inherent trade-off between frame rate and image quality may often lead to suboptimal images. Parallel receive beamforming is used to help overcome this problem, but this introduces artifacts in the images. In addition to the parallel beamforming artifacts found in B-mode imaging, we have found that a difference in curvature of transmit and receive beams gives a bias in the Doppler velocity estimates. This bias causes a discontinuity in the velocity estimates in color flow images. In this work, we have shown that interpolation of the autocorrelation estimates obtained from overlapping receive beams can reduce these artifacts significantly. Because the autocorrelation function varies quite slowly, the beams can be acquired with a considerable time difference, for instance across interleaving groups or across scan planes in a 3-D scan. We have shown that a high frame rate of color flow images can be maintained with parallel beam acquisition with minimal deterioration of the image quality.