Ultrasound: Transcranial Doppler

What Is an Ultrasound?

An ultrasound scan is a medical test that uses high-frequency sound waves to create live images from the inside the body. Also called a sonogram or sonography, ultrasounds let doctors see the body’s soft tissues, which X-rays can’t do.

Doctors order ultrasounds for many reasons, such as to look for the causes of pain, swelling, and infection. Ultrasound scans are safe and painless.

What Is a Transcranial Doppler Ultrasound?

A transcranial Doppler ultrasound uses sound waves to evaluate blood flow (blood circulation) in and around the brain. The test is also called transcranial Doppler (TCD) ultrasonography. This test takes a bit longer to do than other types of ultrasounds. A TCD can take between 30 minutes to 1 hour.

Why Are Transcranial Doppler Ultrasounds Done?

Doctors order transcranial Doppler ultrasounds to check blood vessels when a problem is affecting blood flow to the brain. For children and teens, they might order the test:

to screen kids and teens with sickle cell disease for their risk of stroke
if someone has signs of an ischemic stroke (when blood flow is blocked to part of the brain)
to look for blocked or narrowed blood vessels
if a child had a traumatic brain injury
to check brain function