Fig. 5
From: Settings and artefacts relevant for Doppler ultrasound in large vessel vasculitis
Baseline correction in spectral Doppler. The optimal PRF is without aliasing. The lower the PRF is, the more detailed (larger) the flow curve is. Left: When aliasing occurs it is seen on the flow curve as the top of the graph being cut off and displayed as coming from the bottom of the image. Right: Baseline correction in this carotid artery allows the operator to lower or elevate the baseline until there is room for the whole graph on either side of the baseline. When baseline correction is not sufficient, then PRF must be increased