Pulsed wave doppler processing using aliased spectral data

摘要

A method for producing Doppler ultrasound data at a user-requested pulse repetition frequency (PRF) utilizing undersampled echo signals. Echo signals are created in response to Doppler pulses that are transmitted into the patient at a rate less than a desired PRF. The echo signals are analyzed in the time domain to determine a velocity of scatterers in an area of tissue defined by a range gate. From the velocity, the Doppler shift of the scatterers is determined. The echo signals are interpolated to produce a number of samples equal in number to that which would have been produced had the Doppler pulses been transmitted at the user-requested PRF. The interpolated echo signals are then analyzed in the frequency domain which produces a number of spectra indicative of the velocity and direction of the moving scatterers. From the Doppler shift determined, the correct spectra is selected and displayed for a user. In addition, the present invention can be used to increase the amplitude of the pulses transmitted into a patient by lowering the transmit pulse frequency so that the total amount of ultrasonic energy delivered to the patient remains the same. The larger amplitude transmit pulses produce echo signals having a better signal-to-noise ratio.