Transcranial Doppler (TCD) sonography uses pulsed Doppler ultrasound transmitted through natural acoustic windows in the skull to assess blood flow velocities in the major intracranial arteries. It provides unique real-time hemodynamic data not available from CT or MRI.
Sonographers and technologists perform TCD studies to screen children with sickle cell disease for elevated middle cerebral artery velocities that predict stroke risk, detect cerebral vasospasm after subarachnoid hemorrhage, monitor cerebral perfusion during carotid endarterectomy, identify patent foramen ovale via bubble studies, and evaluate intracranial arterial stenosis. Transcranial color-coded duplex (TCCD) adds real-time imaging to flow measurements.
TCD credentialing falls primarily under the ARDMS Vascular Technology (VT) specialty within the RVT credential. Specialized training programs and competency curricula are offered by the Society of Vascular Ultrasound (SVU). Technologists work in cerebrovascular labs, neurology departments, neurosurgery ICUs, and stroke centers.