Doppler ultrasound common carotid artery

Longitudinal ultrasound image of the right neck with color and spectral Doppler demonstrates the normal sharp upstroke of the common carotid artery waveform. The variety of colors shown within the carotid artery (deep to the internal jugular vein) is called "aliasing," a phenomenon seen when the color scale is set too low for the vessel interrogated. In this case, a venous preset was chosen and a lower velocity scale was selected by the machine.