Skip to main content

Health Encyclopedia

Search the Health Encyclopedia

Duplex ultrasound

Definition

A duplex ultrasound is a test to see how blood moves through your arteries and veins.

Alternative Names

Vascular ultrasound; Peripheral vascular ultrasound

How the Test is Performed

A duplex ultrasound combines:

  • Traditional ultrasound: This uses sound waves that bounce off blood vessels to create pictures.
  • Doppler ultrasound: This records sound waves reflecting off moving objects, such as blood, to measure their speed and other aspects of how they flow.

There are different types of duplex ultrasound exams. Some include:

  • Arterial and venous duplex ultrasound of the abdomen. This test examines blood vessels and blood flow in the abdominal area.
  • Carotid duplex ultrasound looks at the carotid artery in the neck.
  • Duplex ultrasound of the extremities looks at the arms or legs.
  • Renal duplex ultrasound examines the kidneys and their blood vessels.

You may need to wear a medical gown. You will lie down on a table, and the ultrasound technician will spread a gel over the area being tested. The gel helps the sound waves get into your tissues.

A wand, called a transducer, is moved over the area being tested. This wand sends out the sound waves. A computer measures how the sound waves reflect back, and changes the sound waves into pictures. The Doppler creates a "swishing" sound, which is the sound of your blood moving through the arteries and veins.

You need to stay still during the exam. You may be asked to lie in different body positions, or to take a deep breath and hold it.

Sometimes during a duplex ultrasound of the legs, the health care provider may calculate an ankle-brachial (ABI) index. You will need to wear blood pressure cuffs on your arms and legs for this test.

The ABI number is obtained by dividing the blood pressure in the ankle by the blood pressure in the arm. A value of 0.9 or greater is normal.

How to Prepare for the Test

Usually, there is no preparation for this test.

If you are having an ultrasound of your stomach area, you may be asked not to eat or drink after midnight. Tell the person doing the ultrasound exam if you are taking any medicines, such as blood thinners. These might affect the results of the test.

How the Test will Feel

You may feel some pressure as the wand is moved over the body, but there is no discomfort most of the time.

Why the Test is Performed

A duplex ultrasound can show how blood flows to many parts of the body. It can also tell the width of a blood vessel and reveal any blockages. This test is a less invasive option than arteriography and venography.

A duplex ultrasound can help diagnose the following conditions:

A renal duplex ultrasound can also be used after transplant surgery. This shows how well a new kidney is working.

Normal Results

A normal result is normal blood flow through the veins and arteries. There is normal blood pressure and no sign of a narrowing or blockage of a blood vessel.

What Abnormal Results Mean

An abnormal result depends on the specific area being examined. An abnormal result may be due to a blood clot or plaque buildup in a blood vessel.

Risks

There are no risks.

Considerations

Smoking may change the results of an ultrasound of the arms and legs. This happens because nicotine can cause the arteries to shrink (constrict).

References

Goldstein LB. Approach to cerebrovascular diseases. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 406.

Leon LR, Labropoulos N. Vascular laboratory. In: Cronenwett JL, Johnston KW, eds. Rutherford's Vascular Surgery. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 18.

Stone PA, Hass SM. Vascular laboratory. In: Cronenwett JL, Johnston KW, eds. Rutherford's Vascular Surgery. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 16.

Review Date:6/6/2016
Reviewed By:Deepak Sudheendra, MD, RPVI, Assistant Professor of Interventional Radiology & Surgery at the University of Pennsylvania Perelman School of Medicine, with an expertise in Vascular Interventional Radiology & Surgical Critical Care, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

adam.com

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.

We Appreciate Your Feedback!
1. Did you find this information useful?
         Yes
         No
2. Would you recommend this website to family and friends?
         Yes
         No