An ultrasonic diagnostic imaging system with a spectral Doppler display mode comprising: a source of complex echo data samples returned from a location of blood flow; a first spectrogram processor configured to execute an FFT algorithm using a window of a first number of complex echo data samples and to produce first velocity estimates; a second spectrogram processor configured to execute an FFT algorithm using a window of a second number of complex echo data samples, wherein the first number of complex echo data samples is greater than the second number of complex echo data samples, and to produce second velocity estimates; and a select/interpolate processor responsive to the first and second velocity estimates and configured to produce an adaptive Doppler velocity spectrogram; characterized in that: the system further comprises an edge detector having inputs coupled to the spectrogram processors and an output coupled to the select/interpolate processor, wherein the select/interpolate processor produces the adaptive Doppler velocity spectrogram in response to the output of the edge detector, the edge detector comprising: a horizontal edge detector having an input coupled to the first spectrogram processor; and a vertical edge detector having an input coupled to the second spectrogram processor, wherein the select/interpolate processor is responsive to detection of a horizontal spectral segment edge by the horizontal edge detector to select a spectrogram produced by the first spectrogram processor as the adaptive velocity Doppler spectrogram and wherein the select/interpolate processor is responsive to detection of a vertical spectral segment edge by the vertical edge detector to select a spectrogram produced by the second spectrogram processor as the adaptive velocity Doppler spectrogram. a source of complex echo data samples returned from a location of blood flow; a first spectrogram processor configured to execute an FFT algorithm using a window of a first number of complex echo data samples and to produce first velocity estimates; a second spectrogram processor configured to execute an FFT algorithm using a window of a second number of complex echo data samples, wherein the first number of complex echo data samples is greater than the second number of complex echo data samples, and to produce second velocity estimates; and a select/interpolate processor responsive to the first and second velocity estimates and configured to produce an adaptive Doppler velocity spectrogram; characterized in that: the system further comprises an edge detector having inputs coupled to the spectrogram processors and an output coupled to the select/interpolate processor, wherein the select/interpolate processor produces the adaptive Doppler velocity spectrogram in response to the output of the edge detector, the edge detector comprising: a horizontal edge detector having an input coupled to the first spectrogram processor; and a vertical edge detector having an input coupled to the second spectrogram processor, wherein the select/interpolate processor is responsive to detection of a horizontal spectral segment edge by the horizontal edge detector to select a spectrogram produced by the first spectrogram processor as the adaptive velocity Doppler spectrogram and wherein the select/interpolate processor is responsive to detection of a vertical spectral segment edge by the vertical edge detector to select a spectrogram produced by the second spectrogram processor as the adaptive velocity Doppler spectrogram. the system further comprises an edge detector having inputs coupled to the spectrogram processors and an output coupled to the select/interpolate processor, wherein the select/interpolate processor produces the adaptive Doppler velocity spectrogram in response to the output of the edge detector, the edge detector comprising: a horizontal edge detector having an input coupled to the first spectrogram processor; and a vertical edge detector having an input coupled to the second spectrogram processor, a horizontal edge detector having an input coupled to the first spectrogram processor; and a vertical edge detector having an input coupled to the second spectrogram processor, wherein the select/interpolate processor is responsive to detection of a horizontal spectral segment edge by the horizontal edge detector to select a spectrogram produced by the first spectrogram processor as the adaptive velocity Doppler spectrogram and wherein the select/interpolate processor is responsive to detection of a vertical spectral segment edge by the vertical edge detector to select a spectrogram produced by the second spectrogram processor as the adaptive velocity Doppler spectrogram.