What Is a Carotid Doppler Test?

How a Carotid Doppler Test Reveals Your Risk of Having a Stroke

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The Carotid Doppler test, or carotid ultrasound, is a non-invasive test that uses sound waves to detect narrowing of your arteries or potential blockages caused by plaque. It helps your healthcare provider determine if you are at risk of having a stroke and if she needs to prescribe preventative measures.

What do "Carotid" and "Doppler" Mean?

"Carotid" is the name of the arteries in your neck and Doppler (yes, just like on your local weather report), or ultrasound, refers to the sound wave imaging technology.


What Do Carotid Arteries Do?

Your large carotid arteries supply blood to the brain. These arteries can narrow due to arteriosclerosis or other causes and impede blood flow, which can lead to transient ischemic attack ( a mini-stroke) or cerebral vascular accident (a stroke). 

Why Do I Need a Carotid Ultrasound?

A physician prescribes a carotid ultrasound for a variety of reasons, including if

  • you have an increased risk of having a stroke 
  • you have a blockage, known as an occlusion, from plaque, a blood clot or something else
  • your carotid artery is narrowing, known as stenosis
  • your health care provider hears an abnormal sound in your artery

How Should I Prepare?

You typically won't receive a long list of instructions from your physician on how to prepare for your carotid Doppler test. She or another tending health care provider should explain the proper protocol to you and then answer any questions you may have.

Before your test, you may need to

  • sign a consent form
  • stop smoking for at least 2 hours before your appointment
  • stop drinking or eating anything containing caffeine 2 hours before your appointment

How Is it Performed?

For most people, a carotid ultrasound takes an average of 15 to 30 minutes. You can expect your health care practitioner to follow the five steps listed below, but what actually happens may vary depending on your condition, so follow their instructions.

  1. Remove any obstructions to the area, such as clothes or jewelry, as requested.
  2. Lay on a table with your neck bent back slightly.
  3. The ultrasound technician will apply a lubricating, jelly-like substance to both sides of your neck, where the carotid arteries are.
  4. The Doppler or ultrasound wand is moved back and forth over the neck to detect blood flow.
  5. You will hear a "whooshing" sound from the machine.

What About My Test Results?

Once the test is complete, you are free to resume normal activities with no restrictions -- unless your health care provider recommends otherwise. The results should be available within a few days at most.

After your test, here's what happens next.

  1. An ultrasound technician records the completed test on a videotape. 
  2. A diagnostic radiologist reviews the tape to measure blood flow and determine the amount and location of any narrowing of the carotid arteries.
  3. The radiologist then sends a report to your physician. 
  4. She will review the radiologist's written report.
  5. The results of your test, along with other factors determined by your individual condition, guide further treatment recommendations 


    Harvard Medical School Family Health Guide, 2000-2003, President & Fellows of Harvard College

    Johns Hopkins Medical Center: Carotid artery Duplex Scan

    Mayo Clinic: Carotid Ultrasound (2015)

    Taber's Cyclopedic Medical Dictionary, Edition 16, F.A. Davis Company (1989)

    University of Ottawa Heart Institute: Carotid Doppler Test

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