1. A method for automatic optimization in spectral Doppler ultrasound imaging, the method comprising: (a) firing at least first and second sequences of spectral Doppler pulses; (b) determining at least first and second goal values in response to the first and second sequences, respectively; (c) estimating a change of a spectral Doppler parameter from the first and second goal values; and (d) automatically setting the optimal spectral Doppler parameter as a function of the estimated change; wherein (a) comprises transmitting the first sequence in response to a first setting of the spectral Doppler parameter and transmitting the second sequence in response to a second setting of the spectral Doppler parameter, the first setting different than the second setting, and (d) comprises automatically setting the spectral Doppler parameter at a third setting the same or different than one or both of the first and second settings.