Some embodiments include acquisition of color Doppler data associated with a pulse repetition frequency (fPRF) and a baseline shift, detection of a first area of the color Doppler data representing zero flow velocity, detection of a second area of the color Doppler data, detection of a first transition between one or more velocities of the second area and one or more velocities of an adjacent third area of the color Doppler data, detection of a second transition between the third area and an adjacent fourth area of the color Doppler data representing non-zero flow velocities in the first direction, subtraction of a velocity corresponding to fPRF from each of the flow velocities of the third area if the second direction is positive, and addition of the velocity corresponding to fPRF to each of the flow velocities of the third area if the second direction is negative.