Doppler Ultrasound: About This Test

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What is it?

Doppler ultrasound is a medical test that uses sound waves to estimate the speed and direction of blood as it flows through a blood vessel. It helps doctors check blood flow through arteries and veins.

There are no risks linked to an ultrasound test, and it is safe for pregnant women. It won't harm the baby (fetus).

Why is this test done?

Doppler ultrasound is done to:

  • Look for reduced blood flow in major neck arteries. Low blood flow in these arteries can cause a stroke.
  • Find blood clots in leg veins. These clots can cause deep vein thrombosis or an embolism.
  • Check blood flow in a fetus to check the health of the fetus.

How can you prepare for the test?

You may be asked to avoid products that contain nicotine (cigarettes, chewing tobacco) for 30 minutes to 2 hours before the test. Nicotine causes blood vessels to narrow and may give false results.

What happens before the test?

You'll need to:

  • Remove any jewellery that might interfere with the ultrasound scan.
  • Take off all or most of your clothes, depending on which part of your body is being scanned. You'll be given a gown to wear during the test.

What happens during the test?

The doctor or ultrasound technologist will have you lie on your back, side, or stomach, depending on which part of your body is being examined.

  • A gel will be applied to your skin. This helps the passage of sound waves.
  • A hand-held device called a transducer will be moved along your skin.
  • You'll need to stay still during the test.

How long does the test take?

  • The test will take 30 to 60 minutes.

What happens after the test?

  • The scans from the test will be read within a short time, in case a repeat test is needed.
  • You will probably be able to go home as soon as the test has been read.
  • You can go back to your usual activities right away.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Where can you learn more?

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Current as of: October 14, 2016