A Doppler ultrasound is a test that uses high-frequency sound waves to view the motion of fluids in the blood vessels.
Reasons for Test
Doppler ultrasound is used to:
- View the flow of blood through vessels and/or the heart
- View and evaluate blockages to blood flow, such as clots
- Assess build-up of plaque inside a vessel
- Monitor blood flow through repaired blood vessels such as bypass grafts
- Examine a baby's blood flow during a pregnancy
In most cases, there are no complications with this test.
What to Expect
Prior to Test
Your doctor may do the following:
- A physical exam
- Blood or urine tests
In some cases your doctor may instruct you to:
- Fast for 8-12 hours before the test. This will decrease the amount of gas in your intestines and make organs easier to see.
- Have a full bladder before the test. You may need to drink 6 or more glasses of water without going to the bathroom.
- Avoid smoking. Smoking can interfere with test results.
Description of the Test
You will lie on a table. Your doctor will put a gel on the skin over the area that will be examined. The gel helps the sound waves travel between the machine and your body.
The ultrasound machine has a hand-held instrument called a transducer. It looks like a microphone or wand. The transducer is pushed against your skin where the gel was applied. The transducer sends sound waves into your body. The waves bounce off your internal organs and echo back to the transducer. The echoes are changed into images that are shown on a screen. The doctor examines the images on the screen. Photographs of the images may be taken.
You may be asked to change positions or hold your breath during the exam.
Copyright © Nucleus Medical Media, Inc.
The gel will be cleaned from your body. You will be able to return to normal activities in most cases.
How Long Will It Take?
About 30 minutes to 1 hour
Will It Hurt?
A radiologist will examine the images after the test. Your doctor will let you know the results and talk to you about treatment.
Call Your Doctor
After the test, call your doctor if symptoms become worse.
If you think you have an emergency, call for emergency medical services right away.
American Institute of Ultrasound in Medicine
Radiology Info—Radiologic Society of North America
The College of Family Physicians of Canada
General ultrasound. Radiology Info—Radiologic Society of North America website. Available at: https://www.radiologyinfo.org/en/info.cfm?PG=genus. Updated May 30, 2016. Accessed March 1, 2018.
Ultrasound imaging. US Food & Drug Administration website. Available at: https://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/ucm115357.htm. Updated December 4, 2017. Accessed March 1, 2018.
Last reviewed March 2018 by EBSCO Medical Review Board Michael J. Fucci, DO, FACC Last Updated: 5/2/2014