1. In a non-transitory computer readable storage medium having stored therein data representing instructions executable by a programmed processor for solving for shear wave information in medical ultrasound imaging, the storage medium comprising instructions for: determining first displacement of tissue as a function of time caused by a first shear wave in response to a first acoustic transmission along a first scan line, the first displacement being on a fourth scan line spaced from the first scan line by at least second and third scan lines; determining second displacement of tissue as a function of time caused by a second shear wave in response to a second acoustic transmission along the third scan line, the second displacement being on the fourth scan line; determining third displacement of tissue as a function of time caused by a third shear wave in response to a third acoustic transmission along the first scan line, the second displacement being on the second scan line; calculating, for each of a plurality of lateral locations, a delay corresponding to a maximum of correlations of the first and second displacements, of the first and third displacements, and of the second and third displacements; and calculating shear velocity in tissue for each of the plurality of lateral locations as a function of the respective delay.