Transcranial Doppler

What is a transcranial Doppler?

A transcranial Doppler is a noninvasive and painless ultrasound (imaging test) that uses sound waves to examine blood flow in your brain. Your provider might order this test to diagnose conditions that affect how blood flows to and within your brain (cerebrovascular diseases) or to monitor how certain treatments are working.

What is a transcranial Doppler used for?

A transcranial Doppler ultrasound can help your healthcare provider detect, diagnose or monitor a wide range of cerebrovascular diseases, including:

• Cerebral aneurysm.
• Cerebral venous sinus thrombosis.
• Change in intracranial pressure.
• Embolism coming from the heart.
• Patent foramen ovale (PFO).
• Stenosis in brain arteries (atherosclerosis).
• Stroke risk with sickle cell anemia.
• Transient ischemic attack (TIA).
• Vasospasm.

This test can also confirm brainstem death (brain death).

How does a transcranial Doppler work?

A transcranial Doppler ultrasound passes sound waves through the tissues of your skull. These sound waves reflect off blood cells moving within your blood vessels. The ultrasound records the sound waves and displays them on a computer screen. Your radiologist or neurologist will interpret the sound waves’ speed and direction.

How do I prepare for a transcranial Doppler?

You don’t need to do anything special to prepare for a transcranial Doppler ultrasound. It isn’t necessary to change into a hospital gown or remove jewelry before the test.

If you wear contact lenses, your provider may ask you to remove them before the test.

If you wear a head covering, your provider will discuss options with you to adjust or temporarily remove it for the test. They’ll give you privacy so you can make any adjustments before and after the test.

Who performs a transcranial Doppler?

A specially trained ultrasound technologist performs the Doppler. A board-certified radiologist or neurologist will interpret the results.

How is a transcranial Doppler performed?

The steps of a transcranial Doppler ultrasound are as follows:

1. You’ll either lie on a padded examining table or sit in a chair during the test.
2. Your technician will apply a small amount of water-soluble gel to your skin over the area to be examined. They’ll usually apply the gel to either the back or front of your neck, above your cheekbone, in front of your ear or over your eyelid. These are the blood vessel sites that supply your brain. The gel doesn’t harm your skin or stain your clothes.
3. Your technician will use a small wand device called a transducer and move it over the gel. The transducer sends high-frequency sound waves through your brain and captures the returning blood flow information. The ultrasound signal appears as graphs or color pictures on the computer’s display screen.
4. You’ll need to keep your head still and avoid talking during the test.
5. Your provider will wipe the gel off your skin when the test is complete.

With certain tests, your provider will need to insert an IV line into a vein in your arm and inject saline. This helps your provider detect if you have a hole in your heart that allows an embolism to pass from the right to the left side and go up into your brain.

Is a transcranial Doppler painful?

No. There’s no discomfort or pain during the test. The gel may feel cold when your technician applies it. You’ll likely feel light pressure as the transducer moves on your skin.

How long does a transcranial Doppler test take?

A transcranial Doppler usually takes between 30 to 60 minutes. This depends on the type and number of tests ordered. Your provider can give you the best time estimate for your situation.

What can I expect after a transcranial Doppler?

After a transcranial Doppler, your provider will review the results. They may ask you to stay and go over the results on the same day.

You’ll be able to go home the same day as the test. The ultrasound is noninvasive, so you can drive and go about your day as you typically would.

What are the side effects or risks of a transcranial Doppler ultrasound?

A transcranial Doppler ultrasound is a safe test. There are no harmful side effects. An ultrasound doesn’t use radiation, as X-ray tests do.

What type of results do you get after a transcranial Doppler?

A radiologist or neurologist will analyze the images and send a report to your healthcare provider who ordered the test.

Your provider will discuss the test results with you. Results will be either normal or abnormal:

• Normal transcranial Doppler results: Blood flow to and within your brain is as expected.
• Abnormal transcranial Doppler results: Blood flow to or within your brain isn’t moving as expected. This could mean that there’s a blockage or narrowing blood vessels that affect how well blood flows to your brain. Sometimes, this test can show an embolism coming from your heart or passing through a hole in your heart (PFO).

Sometimes, your provider will need a follow-up test to get additional views of a certain area, to monitor a particular medical condition or to see if treatment is working.

Abnormal results may lead to a cerebrovascular disease diagnosis and treatment may follow.

When should I know the results of a transcranial Doppler?

The results are available immediately after the test. Your provider may review those results with you after the test, or they’ll schedule another appointment to go over the results with you.