Fast B-flow imaging: A method for improving frame rate in Golay coded B-flow Imaging

A technique for Golay coded B-flow imaging, called fast B-flow imaging, has been developed. This technique improves the frame rate of Golay coded B-flow imaging. In this technique, three instead of four input pulses are used to produce each scan line. A standard Golay pulse-pair is used as two of the three inputs, and pulse compression is performed upon receive returning the echoes from stationary (tissue) objects in the image. The third input is a repetition of one of the first two inputs. Upon receive, this pulse is cross correlated with an inverted copy of its input pulse. Addition of the cross-correlated signals produced from the identical input pulses results in the cancellation of the strong tissue echoes, and enables visualization of the weaker/moving blood echoes. Combining a small fraction of the tissue echoes with the weaker blood echoes allows both to be visualized in the same gray scale image. By using three instead of four input pulses, this technique can achieve a frame rate improvement of 33% compared with standard Golay coded B-flow imaging, with some loss in signal-to-noise ratio. The impact of axial and lateral motion on these techniques is examined. A quantitative comparison of both techniques is presented.