Transcranial doppler (TCD) ultrasound is a painless test that uses sound waves to detect medical problems that affect blood flow in your brain. It can detect stroke caused by blood clots, narrowed sections of blood vessels, vasospasm due to a subarachnoid hemorrhage, tiny blood clots and more. Learn how the procedure is performed.
Transcranial Doppler (TCD) ultrasound is a painless test that uses sound waves to examine blood flow in your brain. Your doctor has recommended that you have this test to diagnosis a medical condition that affects blood flow to and within the brain. The test is also used to monitor the results of certain treatments, for example, the breakup of clots inside brain arteries.
During TCD, sound waves are sent through the tissues of your skull. These sound waves reflect off blood cells moving within your blood vessels, allowing the radiologist or neurologist to interpret their speed and direction. The sound waves are recorded and displayed on a computer screen.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
Transcranial Doppler ultrasound is used to diagnose or monitor a wide range of medical conditions affecting blood flow, including:
There is no special preparation for transcranial Doppler ultrasound.
A radiologist or neurologist will analyze the images and send a report to your healthcare provider who ordered the test. Your doctor will discuss the test results with you.
Sometimes a follow-up test is needed to get additional views or to monitor a particular medical condition for which the test was ordered or to see if treatment worked.
Transcranial Doppler ultrasound is not hazardous. There are no harmful side effects. Ultrasound doesn’t use radiation, as X-ray tests do.
Last reviewed by a Cleveland Clinic medical professional on 03/30/2021.
Learn more about our editorial process.