Understanding the technology
About This Technology.
Doppler vascular ultrasound is a blood vessel test that uses sound waves. It shows the vessel wall along with the direction and speed of blood flow. Doctors use it to find narrowed or blocked arteries, blood clots in the veins, and leaky vein valves in varicose veins, with no needles and no radiation.
What Is Doppler Vascular Ultrasound?
Doppler vascular ultrasound uses high-frequency sound waves sent from a transducer, a small handheld device placed on the skin. It is often called a duplex ultrasound because it combines two things: a black-and-white image that shows the vessel wall and any plaque, and Doppler, which measures the direction and speed of blood flow. With color Doppler, flow appears as color on the screen. Where a vessel is narrowed, blood flows faster, which helps the doctor estimate where the narrowing is and how severe it is.
Blood Vessels That Can Be Examined
- Leg and arm arteries: to look for narrowings or blockages in peripheral artery disease, and to monitor stents or bypass grafts after a procedure.
- Carotid arteries in the neck: to assess plaque and narrowing linked to stroke risk.
- Abdominal aorta: to measure the diameter of the aorta and detect or monitor an aneurysm, an enlarged section of the aorta.
- Leg veins: to look for blood clots in the deep veins (deep vein thrombosis) and to assess leaky vein valves in varicose veins before treatment.
What You Will Experience
You lie on an examination bed with the area to be examined uncovered. Gel is applied, and the transducer is moved along the blood vessels. You may hear the sound of blood flow from the machine; this is normal. For a vein study, you may be asked to stand, hold your breath, or have your calf squeezed briefly to check the vein valves. An abdominal aorta scan is generally clearer if you fast for a few hours beforehand, because gas in the bowel can block the image.
Limitations and Further Tests
Ultrasound results depend on the skill of the examiner and on your body. Bowel gas, excess body weight, swelling, or heavy calcium in the artery wall can make some vessels hard to see. If the result is unclear or a procedure is being planned, your doctor may recommend CT angiography or angiography. Doppler vascular ultrasound is often used together with the ankle-brachial index (ABI) test: the ABI shows whether blood flow to the legs is reduced, while ultrasound shows where the problem is.
Who Reads the Results
The images and measurements are reviewed by a cardiologist or a radiologist. The results are discussed with you at your consultation, including whether you need medication, a procedure, or regular monitoring.
Clinical use
Uses and Benefits.
Whether this technology suits your condition is decided by a doctor after an evaluation.
- Finding where and how severely the leg and arm arteries are narrowed
- Assessing plaque and narrowing in the carotid arteries of the neck
- Detecting blood clots in the deep veins of the legs
- Assessing leaky vein valves in varicose veins before treatment
- Measuring the abdominal aorta to detect or monitor an aneurysm
- Monitoring stents, bypass grafts, or results after a vascular procedure
Benefits for the Doctor's Assessment
Structure and Flow at the Same Time
Two-dimensional images show the vessel wall and plaque, while Doppler measures flow speed. Together they help the doctor judge both the location and the effect of a narrowing.
No Radiation and No Contrast Dye
The test uses sound waves from the skin surface, with no needles, X-rays, or contrast dye, so it can be repeated for monitoring and does not burden the kidneys.
Arteries and Veins Alike
The same type of test can assess narrowed arteries as well as veins blocked by clots or with leaky valves, depending on the area your doctor requests.
Initial Imaging in Guidelines
The 2024 ESC guidelines on peripheral artery disease and the SVS/AVF/AVLS guidelines on varicose veins recommend duplex ultrasound as initial imaging to confirm and assess the disease.
Brief Technical Information
- Test type
- Duplex ultrasound (two-dimensional imaging and color Doppler)
- Imaging source
- Ultrasound waves, no ionizing radiation
- Vessels examined
- Arteries of the legs, arms, and neck (carotid), the abdominal aorta, and the leg veins
- Needles and contrast
- No needles or contrast dye
- Service location
- Cardiovascular Diagnostic Center and Vascular Diagnostic and Therapeutic Center
