Pixel-based ultrasound image reconstruction: Impact of grid size on signal frequency content

The effect of grid size on the frequency content of the pixel-based image reconstruction algorithms is discussed. It is shown that coarse grid sizes result in simultaneous decimation and down conversion of the axial data. Results of simulations and phantom studies are presented which show the amount of decimation and predicted frequency shifts. The effect of this frequency shift and down-sampling is then studied in terms of a bias in the displacement when narrow-band algorithms are used for speckle tracking.