An ultrasound imaging system (100) may automatically analyze a pulse wave Doppler spectrogram to determine high quality and low quality cardiac cycles. Based on the determination, the ultrasound imaging system (100) may exclude the low quality cardiac cycle from being used in calculations of parameter measurements such as peak systolic velocity, end diastolic velocity, and resistance index. In some examples, the ultrasound imaging system (100) may provide a visual indication on the display (138) which cardiac cycles were excluded from the measurements.