Autocorrelation guided cross-correlation in ultrasound shear wave elastography

An ultrasound motion-estimation method comprising:

• issuing multiple ultrasound pulses, spaced apart from each other in a propagation direction of a shear wave, said shear wave having been induced by an axially-directed push;
• tracking, with the multiple ultrasound pulses, axial motion caused by said shear wave;
• based on said tracking of the axial motion, using autocorrelation to estimate an axial displacement and to quantize the estimate of axial displacement based on consecutive sampling depths to produce a quantized axial displacement;
• and
• using the quantized axial displacement as a pixel-specific starting point in a time-domain based motion tracking algorithm including cross-correlation, wherein the using the quantized axial displacement as a pixel-specific starting point includes positioning a kernel for the cross-correlation by offsetting a kernel used in the autocorrelation by the quantized axial displacement, wherein the time-domain based motion tracking algorithm further includes:
• using an axial lag associated with a maximum cross-correlation coefficient found by the cross-correlation in an interpolation to find a peak cross-correlation coefficient;
• deriving a maximum axial lag from the peak cross-correlation coefficient;
• and
• summing the maximum axial lag and the quantized axial displacement to derive a modified measurement of the axial displacement.

A non-transitory computer readable medium for ultrasound motion-estimation, said medium embodying a program having instructions executable by a processor for performing a plurality of acts, among said plurality there being the acts of:

• issuing multiple ultrasound pulses, spaced apart from each other in a propagation direction of a shear wave, said shear wave having been induced by an axially-directed push;
• tracking, with the multiple ultrasound pulses, axial motion caused by said shear wave;
• based on said tracking of the axial motion, using autocorrelation to estimate an axial displacement and to quantize the estimate of axial displacement based on consecutive sampling depths to produce a quantized axial displacement;
• using the quantized axial displacement to positioning a kernel for cross-correlation by offsetting a kernel used in the autocorrelation by the quantized axial displacement;
• using an axial lag associated with a maximum cross-correlation coefficient found by the cross-correlation in an interpolation to find a peak cross-correlation coefficient;
• deriving a maximum axial lag from the peak cross-correlation coefficient;
• and
• summing the maximum axial lag and the quantized axial displacement to derive a modified measurement of the axial displacement.