Transcranial Doppler (TCD) Ultrasound

Children with sickle cell disease are at risk for stroke. Transcranial (trans-CRANE-ee-ul) Doppler (TCD) ultrasounds help predict that risk. A TCD measures how fast blood is flowing to the brain (Picture 1). 


  • When blood flows faster than it should, there is a higher risk for a stroke. 
  • Children with certain types of sickle cell disease, like Hgb SS or Hgb S Beta Thalassemia Zero, should have TCDs done once a year from ages 2 to 16. Some children may need TCDs more often to watch their risk more closely.
  • TCDs help doctors and health care providers know if your child needs stroke monitoring more often or treatment to avoid stroke.

Preparing for a TCD

  • Before your child’s appointment:
    • Tell them what a TCD is.
    • They can eat and drink normally.
    • Do not give them any medicines that could make them sleepy. They must be awake.
  • You can stay with your child at their appointment. While you’re there:
    • Keep your child awake and help them relax. This will help get the most correct
      TCD results.
    • Bring something for your child to read or watch (without headphones).

How a TCD is Done 

The TCD machine stays on the outside of your child’s body during the test. The test takes around 30 to 60 minutes. 

  • Someone that does ultrasounds, called a sonographer, will put gel on your child’s head. This gel will not stain clothes. It can be wiped off easily. 

  • They will move a small device, called a probe, over the sides of your child’s head and forehead (Picture 2). 
  • Your child needs to stay still as much as possible.

After the Test

  • Your child can return to their normal activities and diet.
  • They should not need any pain medicine after the test.
  • The sickle cell team will contact you with TCD results after the test.
  • Your child is still at risk for having a stroke, even if they have TCDs done regularly.

When to Call 911

Call 911 for emergency help right away if your child has any symptoms of a stroke.

Common stroke symptoms are:

  • Seizures
  • Vomiting
  • Sudden and severe headache
  • Vision changes
  • Trouble speaking
  • Cannot be woken up
  • Any weakness or numbness


  • Your child’s follow up appointment is on (date) ________________ at (time)_________ in the (place) ___________________________.
  • Expect to have regular follow up appointments with your child’s doctor or health care provider. Call your doctor if you can’t keep any appointments or have any questions.


Transcranial Doppler (TCD) Ultrasound (PDF), Somali (PDF), Spanish (PDF)

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