Carotid duplex

Definition

Carotid duplex is an ultrasound test that shows how well blood flows through the carotid arteries. The carotid arteries are located in the neck. They supply blood directly to the brain.

Alternative Names

Scan - carotid duplex; Carotid ultrasound; Carotid artery ultrasound; Ultrasound - carotid; Vascular ultrasound - carotid; Ultrasound - vascular - carotid; Stroke - carotid duplex; TIA - carotid duplex; Transient ischemic attack - carotid duplex

How the Test is Performed

Ultrasound is a painless test that uses sound waves to create images of the inside of parts of the body. The test is done in a vascular laboratory 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 transducer sends sound waves to the carotid arteries in your neck. The sound waves bounce off the blood vessels and create images of the insides of the arteries.

How to Prepare for the Test

No preparation is necessary.

How the Test will Feel

You may feel mild pressure as the transducer is moved around your neck, but the test should not be painful. 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 health care provider may order this test if:

• You have had a stroke or a transient ischemic attack (TIA) that causes temporary weakness, numbness, or visual loss
• 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 provider hears an abnormal sound called a bruit over the carotid neck arteries. This may mean the artery is narrowed.

Normal Results

The results show whether your carotid arteries are narrowed and by how much. For example, an artery may be 10%, 50%, or 75% narrowed.

A normal result means there is no problem with the blood flow through the carotid arteries.

What Abnormal Results Mean

An abnormal result may mean that one or both carotid arteries are narrowed, or something is changing the blood flow. This is often a sign of atherosclerosis or other blood vessel conditions.

In general, the more narrowed the artery is, the higher your risk for stroke.

Depending on your results, your provider may recommend:

• Treatment with medicines or surgery or other procedure
• Additional tests (such as cerebral angiography, CT angiography, and magnetic resonance angiography)
• A heart-healthy diet and lifestyle changes to help slow the progression of atherosclerosis
• Repeat the carotid duplex test to monitor the artery over time

Risks

There are no risks with having this procedure.

References

Adamczyk P, Liebeskind DS. Vascular imaging: computed tomographic angiography, magnetic resonance angiography, and ultrasound. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2027:chap 43.

Bluth EI, Johnson SI, Troxclair L. The extracranial cerebral vessels. In: Rumack CM, Levine D, eds. Diagnostic Ultrasound. 6th ed. Philadelphia, PA: Elsevier; 2024:chap 24.

Goldstein LB. Ischemic cerebrovascular disease. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 376.

Naylor AR, Ratner B, Ancetti S, et al. Editor's Choice – European Society for Vascular Surgery (ESVS) 2023 clinical practice guidelines on the management of atherosclerotic carotid and vertebral artery disease. European Journal of Vascular and Endovascular Surgery. 2023;65(1):7-111. PMID: 35598721 pubmed.ncbi.nlm.nih.gov/35598721/.