Vascular Ultrasound Explained: How Blood Flow Testing Works, What It Shows, and How to Prepare
If your doctor has ordered a vascular ultrasound, you might be wondering what the test involves, whether it hurts, and what the results will tell you. This guide walks through how vascular ultrasound works, the types of vascular ultrasound exams, how to prepare, what happens during the procedure, and what your results mean. There is no radiation, no contrast dye, and the exam is painless. If you need a same-day vascular ultrasound in Glendale, our team at Urgent Diagnostic Imaging Center accepts walk-ins and delivers preliminary results at the end of your visit.
What Is a Vascular Ultrasound?
A vascular ultrasound is a safe, non-invasive circulation test that uses sound waves to create real-time images of the arteries and veins throughout your body. It is also called an arterial and venous ultrasound, a vascular ultrasound test, or a blood flow ultrasound. Your sonographer uses a small handheld transducer to send high-frequency sound waves into the tissue. The waves bounce back and produce a detailed image of your blood vessels along with a real-time measurement of blood-flow velocity and the direction of blood flow.
What Is Vascular Ultrasound Used For?
So what is vascular ultrasound used for? Doctors order vascular ultrasound to check blood circulation and look for narrowing, blockages, or clots in the arteries and veins. Common reasons include:
Suspected deep vein thrombosis (DVT) or a blood clot in the legs or arms
Symptoms of peripheral artery disease (PAD), such as leg pain when walking
Evaluation of the carotid arteries for plaque buildup and stroke risk
Screening for an aortic aneurysm in the abdominal aorta
Checking the renal arteries for narrowing that may cause high blood pressure
Monitoring venous insufficiency or venous reflux that causes leg swelling, varicose veins, or aching
Pre-surgical planning or post-surgical follow-up on grafts, stents, and bypasses
What Does a Vascular Ultrasound Show?
An artery ultrasound or vein ultrasound can show a lot in a single exam. So what does a vascular ultrasound show?
The size, shape, and course of your blood vessels
Plaque buildup, narrowing, or stenosis
Total blockage or occlusion of an artery or vein
The presence and location of a thrombus (blood clot)
The direction and speed of blood flow
Signs of venous insufficiency, valve failure, or venous reflux
Signs of venous insufficiency, valve failure, or venous reflux
Types of Vascular Ultrasound
There are several types of vascular ultrasound, and your provider may order one or a combination depending on what they need to see.
Duplex Ultrasound
A duplex ultrasound combines two imaging techniques in one exam: standard grayscale ultrasound to show the vessel’s structure, and Doppler to measure blood flow. It is called duplex imaging because it does both at the same time. Most modern vascular ultrasound exams are duplex studies.
Doppler Ultrasound (Color and Spectral)
A Doppler ultrasound measures how blood moves through your vessels. Color Doppler overlays a color map on the vessel image so you can see the direction of flow (typically red for flow toward the transducer and blue for flow away). Spectral Doppler produces a graph of blood-flow velocity over time, which helps identify narrowing and blockages. A vascular Doppler ultrasound is usually included as part of a duplex study.
Compression Ultrasound
Compression ultrasound is a specific technique used to look for deep vein thrombosis. Your sonographer applies gentle pressure with the transducer over a vein. Healthy veins compress easily; a vein containing a clot will not, which makes this a quick and reliable way to rule out DVT.
Ankle-Brachial Index (ABI)
An ankle-brachial index compares the blood pressure in your ankle to the blood pressure in your arm using blood pressure cuffs and a Doppler probe. A low ratio suggests peripheral artery disease in the legs. ABI is often performed alongside an arterial Doppler study.
Common Vascular Studies by Body Area
Vascular ultrasound is tailored to what your physician needs to see. The most common studies include:
Carotid duplex: the neck arteries that supply the brain
Venous Doppler of the lower extremities: leg veins, most often for suspected DVT or venous insufficiency
Arterial Doppler of the upper and lower extremities: arm and leg arteries, for PAD or other circulation symptoms
Abdominal aortic ultrasound: screening for aortic aneurysm
Renal artery Doppler: kidney arteries when high blood pressure or unexplained kidney dysfunction is being investigated
How to Prepare for a Vascular Ultrasound
Vascular ultrasound preparation is minimal for most exams. Here is how to prepare based on the type of study you are scheduled for.
Extremity studies (legs, arms, neck): No special preparation is required. Wear loose-fitting clothing that gives easy access to the area being scanned.
Abdominal studies (aorta or renal arteries): Fast for 6 to 8 hours before the exam so air in the digestive tract does not block the view. Water and necessary medications are usually fine.
Bring with you: insurance card, photo ID, list of current medications, and any prior imaging on CD or in a patient portal.
Tell your sonographer if you have any implants, grafts, stents, or prior vascular surgery so the exam can be tailored to your history.
What Happens During the Procedure
Here is a step-by-step look at the vascular ultrasound procedure so you know what to expect.
Check in and change if needed. Some studies require a gown; extremity exams often do not.
Positioning. You will lie on the exam table in whatever position best exposes the area being studied.
Warm gel is applied to the skin to help the sound waves travel.
The scan. Your sonographer moves the transducer over the area. You may hear swishing sounds during the Doppler portion. That is your blood flow.
Blood pressure cuffs may be placed on your arms or legs for arterial studies.
Wrap-up. The gel is wiped off, and you can get dressed and go home right away.
How Long Does a Vascular Ultrasound Take?
How long does a vascular ultrasound take? Most exams take 30 to 60 minutes. A single-area study like a carotid duplex or a compression ultrasound for DVT lands on the shorter end. Studies that involve both legs, both arms, or additional measurements like an ankle-brachial index take longer. There is no recovery time.
Understanding Your Vascular Ultrasound Results
After your exam, a board-certified radiologist reviews the images and prepares a report describing vessel structure, blood flow patterns, any narrowing or blockages, and the presence or absence of clots. Vascular ultrasound results are typically summarized as normal, mild/moderate/severe narrowing, or occlusion. At our clinic, preliminary results are available at exam completion, final reports are faxed to your referring physician the same day, and STAT reports are delivered within one hour for urgent cases.
Frequently Asked Questions
Is a vascular ultrasound painful?
No. A vascular ultrasound is painless. You may feel light pressure from the transducer, and if blood pressure cuffs are used they will feel like a standard blood pressure check.
Does a vascular ultrasound use radiation or contrast dye?
No, and no. Vascular ultrasound uses only sound waves. There is no radiation, no injectable contrast dye, and no needles.
What is the difference between a vascular ultrasound and a Doppler ultrasound?
A vascular ultrasound is the exam category. Doppler ultrasound is the specific technique used to measure blood flow within the exam. Most modern vascular ultrasound studies are duplex ultrasound studies, meaning they combine grayscale imaging with Doppler flow measurement in a single visit.
Can a vascular ultrasound detect blocked arteries?
Yes. Vascular ultrasound is one of the first-line tests for detecting arterial narrowing, plaque buildup, and full blockages, especially in the carotid, leg, and arm arteries. For the coronary arteries specifically, additional imaging is required.
Can I eat before a vascular ultrasound?
Yes, for extremity and neck studies. For abdominal studies (aorta or renal arteries), you will be asked to fast for 6 to 8 hours so air in the digestive tract does not block the view.
Can I drive or return to work after a vascular ultrasound?
Yes. There is no sedation, no recovery time, and no restrictions after the exam. You can drive yourself home and return to normal activity immediately.
When will I receive my vascular ultrasound results?
Preliminary results are available at the end of your exam. Final reports are faxed to your referring physician the same day, and STAT reports are delivered within one hour when needed.
Same-Day Vascular Ultrasound at Urgent Diagnostic Imaging Center in Glendale
If you need a vascular ultrasound in Glendale, our team at Urgent Diagnostic Imaging Center accepts walk-ins during business hours (Monday through Friday, 9 AM to 8 PM, and weekends, 9 AM to 5 PM). Our ARDMS-licensed sonographers and board-certified radiologists deliver preliminary reports at exam completion and same-day finals for your physician.
To see our full range of diagnostic imaging services, including echocardiogram, general ultrasound, X-ray, and 3D breast ABUS, visit our services page. Ready to book vascular ultrasound? Call (818) 240-7744, book online, or walk into 1030 S. Glendale Ave, #405, Glendale CA 91205.
