Carotid Artery Doppler Scan
(Carotid Ultrasound, Vascular Ultrasound Study, Carotid Artery Doppler Sonography)
Procedure Description
A carotid artery doppler scan is a type of vascular ultrasound study done to assess the blood flow of the arteries that supply blood from the heart through the neck to the brain. There are four carotid arteries - the right and left internal carotid arteries and the right and left external carotid arteries. One pair (external and internal) is located on each side of the neck.
A carotid artery doppler scan (also called a carotid duplex) is a noninvasive (the skin is not pierced) procedure. A transducer sends out ultrasonic sound waves at a frequency too high to be heard. When the transducer is placed on the carotid arteries at certain locations and angles, the ultrasonic sound waves move through the skin and other body tissues to the blood vessels, where the waves echo off of the blood cells. The transducer picks up the reflected waves and sends them to an amplifier, which makes the ultrasonic sound waves audible. Absence or faintness of these sounds may indicate an obstruction to the blood flow.
A related procedure that may be performed to further evaluate the carotid artery and its branches is cerebral angiography. Please see this procedure for more information.
A carotid artery doppler scan is used to assess occlusion (blockage) or stenosis (narrowing) of the carotid arteries of the neck and/or the branches of the carotid artery. Plaque (a build up of fatty materials), thrombus (blood clot), and other substances in the blood stream may cause a disturbance in the blood flow through the carotid arteries.
When the carotid arteries become blocked, symptoms may include confusion, drowsiness, headache, and/or a brief loss of ability to speak or move. These symptoms may indicate early warning signs of a possible stroke (brain attack, or cerebrovascular accident [CVA]).
Additional reasons for the procedure include, but are not limited to, the following:
- evaluation of previous procedures to restore blood flow to the area (such as an angioplasty to open up an artery that was blocked or surgery to bypass a blocked artery)
- evaluation of carotid blood flow prior to a major cardiovascular surgical procedure, such as coronary artery bypass grafting or heart valve repair/replacement
There may be other reasons for your physician to recommend a carotid artery doppler scan.
There is no radiation used and generally no discomfort from the application of the ultrasound transducer to the skin.
There may be risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.
Certain factors or conditions may interfere with the results of the test. These include, but are not limited to, the following:
- severe obesity
- irregular heart rhythms (arrhythmias)
- cardiac disease
Patient Preparation
- Your physician will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.
- You may be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully and ask questions if something is not clear.
- Generally, no prior preparation, such as fasting or sedation, is required.
- Your physician may give you specific instructions about smoking and consuming caffeine. You may be asked to refrain from smoking for at least two hours before the test, as smoking causes blood vessels to constrict. You may also be asked to refrain from consuming caffeine in any form for about two hours prior to the test.
- Based on your medical condition, your physician may request other specific preparation.
A carotid artery doppler scan may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your physician's practices.
Generally, a carotid artery doppler scan follows this process:
- You will be asked to remove any clothing, jewelry, or other objects that may interfere with the scan.
- If you are asked to remove clothing, you will be given a gown to wear.
- You will lie on an examination table with your neck slightly extended (bent backward).
- A clear gel will be placed on the skin at various locations on the carotid arteries.
- The Doppler transducer will be pressed against the skin and moved around over the area of the artery being studied.
- When blood flow is detected, you will hear a "whoosh, whoosh" sound. The probe will be moved around to compare blood flow in different areas of the artery. Both sides of the neck will be examined.
- Once the procedure has been completed, the gel will be wiped off.
The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort.
While the carotid artery doppler scan procedure itself causes no pain, having to lie still for the length of the procedure might cause slight discomfort.
There is no special type of care required after a carotid artery doppler scan. You may resume your usual diet and activities unless your physician advises you differently.
Frequently Asked Questions about Carotid Dopplers
Q. Does the test hurt?
A. Generally, there is little or no discomfort during the procedure.
Q. How long does the test take?
A. The itself may take anywhere from 20 to 45 minutes.
Q. What is the test looking for?
A. See prior discussion above.
Useful Links About This Procedure
The content provided here is for informational purposes only, and was not designed to diagnose or treat a health problem or disease, or replace the professional medical advice you receive from your physician. Please consult your physician with any questions or concerns you may have regarding your condition.
This page contains links to other Web sites with information about this procedure and related health conditions. We hope you find these sites helpful, but please remember we do not control or endorse the information presented on these Web sites, nor do these sites endorse the information contained here.
Alzheimer's Association
American Academy of Orthopaedic Surgeons
American Academy of Neurology
American Cancer Society
American Heart Association
American Stroke Association
Brain Injury Association
Epilepsy Foundation of America
National Cancer Institute
National Institute for Neurological Disorders and Stroke
National Institutes of Health (NIH)
National Library of Medicine
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