The Carotid Doppler exam uses sound frequency in a range that is higher than human beings are able to hear to produce images of the carotid arteries in the neck on a viewing screen. The blood flow through these arteries is evaluated with Doppler and Color Doppler. Color Doppler involves the use of standard ultrasound methods to produce a picture of a blood vessel. In addition, a computer converts the Doppler sounds into colors (typically red and blue) that are overlaid on the image of the blood vessel. These colors represent the speed and direction of blood flow through the vessel.

Carotid Doppler studies are used to demonstrate blocked or reduced blood flow in the arteries of the neck that could cause stroke. This test is also used to evaluate symptoms of dizziness, vision changes and loss of balance that may be caused by impeded or restricted blood flow through these vessels

The room is usually darkened for the exam. A gel is applied to the neck area to provide good contact for the handheld transducer. The transducer is placed on the neck and sound is sent into the body and is reflected off arteries and returned to the transducer. The echoes are converted electronically into images of the arteries that can be seen on a monitor. These images are recorded on paper or film. With Doppler and Color Doppler the sound waves reflected from the blood cells are converted to audible sounds that can be heard during the exam. Color is used to represent the blood flow in the artery and the speed and direction of the flow are assessed by the physician. This procedure takes approximately 45 minutes.