Retrospective PW-Doppler based on spatiotemporal adaptive signal processing

The trade-off between temporal and spectral resolution in conventional PW Doppler may limit duplex/triplex quality and the depiction of rapid flow events. This work investigates how the observation time can be reduced by adaptive spectral estimation utilizing 2-D spatial information obtained by parallel receive beamforming (PRB). Two adaptive estimation techniques were investigated, the power spectral Capon (PSC) method and amplitude and phase estimation (APES). The PSC approach was preferred due to a superior spectral resolution and lower computational demands. Good results were obtained using both focused and unfocused transmit beams, and a 2-3 times increase in temporal resolution could be achieved. Spectra retrospectively calculated from CFI became feasible, which may provide new clinical information by inspection of velocity spectra simultaneously from several spatial locations.