Carotid duplex is an ultrasound test that shows how well blood is flowing through the carotid arteries. The carotid arteries are located in the neck. They supply blood to the brain.
Scan - carotid duplex; Carotid ultrasound; Carotid artery ultrasound; Ultrasound - carotid; Vascular ultrasound - carotid; Ultrasound - vascular - carotid
How the Test is Performed
The test is done in a vascular lab or radiology department of a hospital. You will be asked to lie on your back. Your head will be supported to prevent it from moving.
The health care provider applies a water-soluble gel on your skin and gently runs a handheld device called a transducer over the area of the carotid arteries in your neck.
The device sends high-frequency sound waves to the arteries in your neck. The sound waves bounce off the blood vessels and form images or pictures of the insides of the arteries.
How to Prepare for the Test
No preparation is necessary.
How the Test Will Feel
You may feel some pressure as the probe is moved around your neck. The pressure should not cause any pain. You may also hear a "whooshing" sound.
Why the Test is Performed
The carotid duplex test checks blood flow in the carotid arteries. It can detect:
- Blood clotting (thrombosis)
- Narrowing in the arteries (stenosis)
- Other causes of blockage in the carotid arteries
Your doctor may order this test if:
- You have had a stroke or transient ischemic attack (TIA)
- You need a follow-up test because:
- The carotid artery was found to be narrowed in the past
- You have had surgery on your carotid artery
- Your doctor hears an abnormal sound called a bruit over the carotid neck arteries. This may mean the artery is narrowed.
The results will tell your doctor how open or narrowed your carotid arteries are. For example, the arteries may be 10% narrowed, 50% narrowed, or 75% narrowed.
A normal result means there is no problem with the blood flow in the carotid arteries. The artery is free of any blockage, narrowing, or other problem.
Note: Value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
An abnormal result means the artery may be narrowed, or something is changing the blood flow in the carotid arteries. This is a sign of atherosclerosis or blood vessel conditions.
In general, the more narrowed the artery is, the higher your risk for stroke.
Depending on the results, your doctor may want you to:
- Consider surgery
- Have additional tests (such as cerebral angiography, CT angiography, and magnetic resonance angiography)
- Follow a healthy diet and lifestyle to prevent atherosclerosis
- Repeat the test again in the future
See the article on atherosclerosis for further treatment information.
There are no specific risks related to having this procedure.
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Meschia JF, Brott TG, Hobson RW 2nd. Diagnosis and invasive management of carotid atherosclerotic stenosis. Mayo Clin Proc. 2007;82(7):851-858.
Hobson RW 2nd, Mackey WC, Ascher E, Murad MH, Calligaro KD, Comerota AJ, et al. Society for Vascular Surgery. Management of atherosclerotis carotid artery disease: clinical practice guidelines of the Society for Vascular Surgery. J Vasc Surg. 2008;48:480-486.
International Carotid Stenting Study Investigators, Ederle J, Dobson J, Featherstone RL, Bonati LH, van der Worp HB, et al. Carotid artery stenting compared with endarterectomy in patients with symptomatic carotid stenosis (International Carotid Stenting Study): an interim analysis of a randomized controlled trial. Lancet. 2010;375:985-997.
Reviewed By: Luc Jasmin, MD, PhD, Department of Neurosurgery, Cedars Sinai Medical Center, Los Angeles, and Department of Anatomy, University of California, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.