Improved color flow mapping using the wideband maximum likelihood estimator

The use of the wideband maximum likelihood estimator (MLE) is shown to improve the color flow mapping of the blood velocity profile. Using a transmitted signal with a significant fractional bandwidth, it is shown that the wideband MLE improves the quality of the color flow estimate and simultaneously allows an increase in the frame rate. It is the improved global accuracy of the estimate, with the use of a new signaling scheme, that allows an increase in the frame rate of the display. The signaling scheme interleaves transmission of pulses in two or three directories. This interleaving, with nonperiodic transmission, reduces the total number of pulses required to achieve a fixed level of local and global accuracy. To study the overall estimator performance, the authors evaluate the expected estimator output and demonstrate that the width of the mainlobe and height of subsidiary peaks are reduced through the use of this estimator and signaling scheme.