What is the role of transcranial Doppler (TCD) ultrasonography in the management of sickle cell disease (SCD)?

Updated: May 12, 2021
  • Author: Joseph E Maakaron, MD; Chief Editor: Emmanuel C Besa, MD  more...
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Transcranial Doppler ultrasonography (TCD) can identify children with SCD who are at high risk for stroke by documenting abnormally high blood flow velocity in the large arteries of the circle of Willis—the middle cerebral or internal carotid arteries. Velocity, which is usually increased by severe anemia, becomes elevated in a focal manner when stenosis reduces the arterial diameter. (MRI, with or without angiography, and NPM studies have also been used to detect these abnormalities.)

The upper limit of normal flow velocity varies with the method used. Values are lower for duplex Doppler (180 cm/s) than for non–duplex Doppler (200 cm/s).

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