Final answer:
Transcranial Doppler (TCD) is used in children with sickle cell disease to assess their risk for stroke by measuring the velocity and blood flow in the major arteries of the brain. It helps identify those at higher risk so that preventive measures can be taken.
Step-by-step explanation:
Transcranial Doppler (TCD) is a non-invasive diagnostic tool used in children with sickle cell disease to assess their risk for stroke. It measures the velocity and blood flow in the major arteries of the brain to detect abnormalities. Children with sickle cell disease are at an increased risk for stroke due to the abnormal shape of their red blood cells. TCD can help identify those at higher risk so that preventive measures can be taken.