A carotid doppler uses an ultrasound scanner and takes 15-30 minutes. During your scan, a probe will be passed over both sides of your neck. The sound waves bounce off your arteries and are passed back through the microphone to a computer. The computer measures these sound waves and the changes in frequency. The echo will be different in areas where the artery has narrowed.
A clear gel will be spread on both sides of your neck. This gel helps to transmit the sound waves to the probe. The probe will be pressed onto your skin and moved back and forth over your neck.