Fig. 10

Flow patterns in low-degree to moderate stenosis. a) B-mode and CD of the CB show a plaque (arrowhead) and increased velocities in the ICA (short arrow), respectively. PW measures a moderate velocity and spectral broadening (*). b) VFI at low PRF, at the peak systole (arrowhead) shows high-velocity red vectors. Long red vectors due to aliasing (arrow), start at the blue dot (void arrow), move back. Vector velocity (white arrow) is higher than the measured PW. c) At high PRF, VFI displays the higher velocities at the stenosis level (orange/yellow vectors). Reverse red vectors (arrow) start from the blue dot (void arrow). In b), c) recirculation depicted by green vectors (*). CCA = Common carotid artery. ICA = Internal carotid artery. ECA = External carotid artery