Scan – carotid duplex; Carotid ultrasound; Carotid artery ultrasound; Ultrasound – carotid; Vascular ultrasound – carotid; Ultrasound – vascular – carotid
A 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 directly to the brain.
How the Test is Performed
Ultrasound is a painless method that uses sound waves to create images of the inside of the body. The test is done in a vascular lab or radiology department.
The test is done in the following way:
- You lie on your back. Your head is supported to keep it from moving. The ultrasound technician applies a water-based gel to your neck to help with the transmission of the sound waves.
- Next, the technician moves a wand called a transducer back and forth over the area.
- The device sends 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 transducer is moved around your neck. The pressure should not cause any pain. You may also hear a “whooshing” sound. This is normal.
Why the Test is Performed
This 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 your carotid artery was found to be narrowed in the past or you have had surgery on the artery
- Your doctor hears an abnormal sound called a bruit over the carotid neck arteries. This may mean the artery is narrowed.
Why might I need a carotid artery duplex scan?
You may need this scan if your healthcare provider thinks you may have:
- A blockage in a carotid artery
- Narrowing (stenosis) in a carotid artery
A blockage may be caused by a buildup of fatty material (plaque), a blood clot (thrombus), or other substances.
Symptoms of blockage may include:
- Dizziness
- Confusion
- Drowsiness
- Headache
- Temporary blindness in one eye
- Temporary inability to speak or move
These symptoms may be early warning signs of a stroke.
You may also need this scan even if you have no symptoms but your healthcare provider hears an abnormal sound (bruit) in an artery. This abnormal sound may mean that you have a problem with blood flow in the artery.
Here are other reasons you may have this scan:
- To see how well blood is flowing after a procedure done on an artery. This may have been a procedure to open up an artery (angioplasty) or surgery to bypass a blocked artery.
- To see how well blood is flowing before you have major heart surgery. This surgery may be bypass surgery or surgery to fix or replace a heart valve.
- To find where clotted blood has collected (hematoma)
- To find out if an artery wall has split (dissection). This may cause a blockage or weaken the artery wall.
Your healthcare provider may have other reasons to recommend a carotid artery duplex scan.
Normal Results
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 significant blockage, narrowing, or other problem.
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 other blood vessel conditions.
In general, the more narrowed the artery is, the higher your risk of 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 hardening of the arteries
- Repeat the test again in the future
Risks
There are no risks with having this procedure.
How do I get ready for a carotid artery duplex scan?
- Your healthcare provider will explain the procedure to you. Ask him or her any questions you have about the procedure.
- You may be asked to sign a consent form that gives permission to do the test. Read the form carefully and ask questions if anything is not clear.
- You don’t need to stop eating or drinking before the test. You also will not need medicine to help you relax (sedation).
- If you smoke, you may need to stop for at least 2 hours before the test. Smoking causes blood vessels to narrow. You may also be asked to not drink or eat any foods with caffeine for about 2 hours before the test.
- Follow any other instructions your provider gives you to get ready.
What happens during a carotid artery duplex scan?
You may have this scan as an outpatient or as part of your stay in a hospital. The way the test is done may vary depending on your condition and your healthcare provider’s practices.
Generally, a carotid artery duplex scan follows this process:
- You will be asked to remove any clothing, jewelry, or other objects that may get in the way of the scan.
- You will be given a gown to wear.
- You will lie on an exam table with your neck slightly bent backward.
- The technologist will put a clear gel on the skin over the area where the carotid arteries are.
- The Doppler transducer will be pressed against the skin and moved around over the area of the artery being looked at.
- When blood flow is detected, you will hear a “whoosh, whoosh” sound. The probe will be moved around to look at blood flow in different areas of the artery. Both sides of your neck will be looked at.
- Once the test is done, the technologist will wipe off the gel.
The carotid artery duplex scan is not painful. But you may have some discomfort from lying still during the test. The technologist will use all possible comfort measures and finish the procedure as quickly as possible to minimize any discomfort.
What happens after a carotid artery duplex scan?
You don’t need any special care after a carotid artery duplex scan. You may go back to your usual diet and activities unless your doctor tells you otherwise.
Your healthcare provider may give you other instructions, depending on your situation.
Next steps
Before you agree to the test or the procedure make sure you know:
- The name of the test or procedure
- The reason you are having the test or procedure
- What results to expect and what they mean
- The risks and benefits of the test or procedure
- What the possible side effects or complications are
- When and where you are to have the test or procedure
- Who will do the test or procedure and what that person’s qualifications are
- What would happen if you did not have the test or procedure
- Any alternative tests or procedures to think about
- When and how will you get the results
- Who to call after the test or procedure if you have questions or problems
- How much will you have to pay for the test or procedure
FAQ
What does a carotid duplex test for
- A carotid duplex ultrasound is performed to evaluate symptoms including dizziness, loss of memory, stroke, loss of muscle control, and other symptoms that might result from narrowing or blockage of the vessels (carotid arteries) on either side of your neck. A carotid ultrasound can also be used to screen for stroke risk.
Why would a doctor order a carotid Doppler?
- A carotid ultrasound is performed to test for narrowed carotid arteries, which increase the risk of stroke. Carotid arteries are usually narrowed by a buildup of plaque — made up of fat, cholesterol, calcium, and other substances that circulate in the bloodstream.
What are normal carotid duplex results?
- Most vascular laboratories use traditional duplex criteria that characterize the carotid bifurcation as normal, 1% to 15% stenosis, 16% to 49% stenosis, 50% to 79% stenosis, 80% to 99% stenosis, and complete occlusion.
How do they do a carotid duplex?
- The technician will move a small ultrasound wand along the area where your carotid arteries are located. You may feel slight pressure and hear a whooshing noise. That’s the sound of your blood moving through your vessels. The ultrasound images are sent to a computer and recorded for your doctor.
