A transcranial Doppler (TCD) test is an ultrasound-based medical test. You may already be familiar with ultrasound technology because of its wide range of uses in diagnosing medical conditions and monitoring during pregnancy. A TCD is an ultrasound performed at the base of the brain to provide information about the speed of blood flow in the brain and assess the risk of a stroke.
What you can expect
A TCD test doesn’t require any preparation on your part. The process of a TCD test involves the following:
- You’ll be asked to lie on an examining table or sit upright.
- At the beginning of the test, the TCD technician will apply a harmless gel to the skin over your temple to help the sound waves transmit into your body.
- The TCD technician will then pass a handheld wand called a transducer over your temple. The transducer emits sound waves that bounce off blood cells and are picked up again by the transducer while a computer interprets these sound-wave signals.
- To assess your stroke risk, the TCD technician may pass the wand over your carotid arteries (arteries in your neck) and arteries at the base of your brain.
- After the test, you’ll be able to get back to your day and resume your regular activities.
There are no known harmful effects of ultrasound or repeated ultrasounds.