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Transcranial Doppler Ultrasound


Transcranial Doppler (TCD) ultrasound is a test that uses sound waves to measure blood flow in your brain. It shows the speed and direction of blood through the blood vessels in your brain. It may also show how the blood vessels react to medicines or position changes. Your healthcare provider may use this test to learn if you are at risk for a stroke. TCD may reveal blood clots or areas of your brain that need more oxygen. TCD may also show narrowed blood vessels, injury, or internal bleeding in your brain. This test may help find and prevent serious health problems, or monitor how well other treatments are working for you.


You or a close family member will be asked to sign a legal document called a consent form. It gives healthcare providers permission to do the procedure or surgery. It also explains the problems that may happen, and your choices. Make sure all your questions are answered before you sign this form.

Before the test:

Tell your healthcare provider what medicines you are taking. Also tell him if you have diabetes, COPD, emphysema, or any other lung condition. Tell him if you smoke or have high blood pressure. These factors may affect your test results.


TCD is performed on the outside of your head. Your healthcare provider will place gel on the tip of the TCD probe. Your healthcare provider will gently move the probe across your temple, neck, eyelid, chin, or ear. He may hold the probe during a test, or secure it in place to monitor you during surgery. Your healthcare provider may ask you to change positions to increase or decrease the blood flow in your brain. You may be asked to lie down, squat, sit, or stand during this test, if you are able. Your healthcare provider may ask you to lie on your side, with your chin tucked towards your chest. He may ask you to open and close your eyes, hold your breath, or breathe heavily. He may also ask you to strain as if you are lifting something heavy. You may be given medicine to widen or shrink your blood vessels. Healthcare providers may place blood pressure cuffs on your thighs.

Transcranial Doppler Ultrasound

After the test:

You may need this test more than once. You may also need other tests to help healthcare providers learn more about your condition.


  • You have new or worsening signs or symptoms.
  • You have questions or concerns about your condition or care.


Heat from the TCD probe may burn your skin. You may be at risk for an infection if TCD is done near your eyes or open wounds. Talk to your healthcare provider if you have questions or concerns about these risks.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.