What Is a Carotid Duplex Scan?

A carotid duplex scan is a simple and painless test that combines two types of ultrasound to look for blockages in your carotid arteries. An ultrasound is a type of scan that uses sound waves to produce a picture of the inside of your body. Your carotid arteries are located along both sides of your neck. Blocked carotid arteries are a major risk factor for stroke.

The two types of ultrasound used in a carotid duplex scan are conventional ultrasound and Doppler ultrasound. Conventional, or B-mode, ultrasound uses sound waves that bounce off blood vessels to provide a picture of the structure of your blood vessel. Doppler ultrasound uses sound waves that track moving objects. This allows your doctor to see how your blood is moving through your blood vessels.

Other names for a carotid duplex scan are:

  • carotid artery duplex scan
  • carotid ultrasound
  • vascular ultrasound
  • carotid artery Doppler sonography

Carotid artery disease is a major risk factor for stroke. The buildup of cholesterol plaques in your carotid arteries can create blood clots. If these clots break off, they can travel to your brain and cause a stroke.

The first symptom of carotid artery disease is often a stroke or ministroke. Some early warning symptoms of a stroke are:

  • weakness, numbness, or tingling on one side of your body or in your arm or leg
  • an inability to move your arm or leg
  • an inability to speak clearly, or having garbled speech
  • an inability to see in one eye, or tunnel vision

See your doctor immediately if you experience any of these warning signs, even if they go away. It could mean that you’ve had a stroke or that you’re about to have one.

When you see your doctor, they’ll ask you questions about your symptoms and your medical history. Your doctor may also listen to the blood flow in your neck and will measure your blood pressure. If your doctor thinks you have carotid artery disease, they’ll order a carotid duplex scan.

As we age, our arteries tend to develop a sticky substance called plaque. Plaque buildup is related to:

  • smoking
  • not getting enough exercise
  • having high triglyceride (fat) or cholesterol levels in the blood
  • being overweight or obese
  • having diabetes
  • having certain genetic factors
  • having high blood pressure

If plaque builds up in your carotid arteries, it’s called carotid artery disease. According to the Society for Vascular Surgery, about 1 percent of adults aged 50 to 59 have carotid artery disease and 10 percent of adults aged 80 to 89 have it.

You may be asked not to smoke or drink caffeine for at least two hours before the test. Smoking and caffeine use can shrink your blood vessels and affect the accuracy of the test.

Wear comfortable clothing with an open neck. Avoid turtlenecks or silk clothing, which could be stained by the ultrasound gel. Remove any jewelry.

A carotid duplex scan takes about 15 to 30 minutes and takes place in an ultrasound lab. The following steps take place during this procedure:

  1. You’ll lie down on the examination table with your head bent slightly backward.
  2. An ultrasound technician will apply a gel to your neck.
  3. They’ll then move a small ultrasound wand along the area where your carotid arteries are located. You may feel slight pressure and hear a whooshing noise, which is the sound of your blood moving through your vessels.
  4. The ultrasound images are sent to a computer and recorded for your doctor.

Ultrasound is a risk-free method to view changes and abnormalities in your body, including during pregnancy.

Most cases of carotid disease are diagnosed by using a carotid duplex scan. Your doctor can order more tests if they need more information.

If your doctor diagnoses you with carotid artery disease, they’ll recommend treatment based on how severe it is. You may need surgery to remove the plaque in your arteries, or you might need what’s called “carotid angioplasty and stenting.”

During carotid angioplasty and stenting, your doctor threads a catheter up through your carotid artery to the location of the blockage. The catheter inflates a small balloon to flatten the plaque. Then, a stent is inserted to keep your arteries open. A stent is a small, metal mesh tube.

Your doctor may also prescribe medications to thin your blood or control the levels of lipids in your blood. Lifestyle changes, including quitting smoking, adopting a healthier diet, and exercising, are also important for preventing and treating carotid artery disease.