Description of broad-band pulsed Doppler ultrasound processing using the two-dimensional Fourier transform.

Considering data from a Doppler sample volume as a two-dimensional function of depth and time, the properties of its two-dimensional fast Fourier transform (2DFFT) are discussed. It is shown that the 2DFFT of idealized Doppler data from moving scatterers is a line whose slope is the velocity of the scatterers. Aliasing, finite bandwidth effects, and spectral broadening due to transit time effects receive simple descriptions in this scheme. Existing processing schemes can be described graphically in this unifying description. Processing of broad band pulsed Doppler ultrasound can incorporate a correction for aliasing if based on the two-dimensional Fourier transform, and this has been tested using data from tissue-mimicking phantom in a tank-based experiment.