transcranial Doppler
Also written as: TCD — transcranial Doppler
Non-invasive ultrasound technique for assessing intracranial arterial blood flow velocities through temporal bone acoustic windows.
Full Definition
Transcranial Doppler (TCD) ultrasonography is a specialized non-invasive technique that employs low-frequency ultrasound to assess blood flow velocities and patterns in major intracranial arteries through natural acoustic windows in the skull. The examination typically utilizes the temporal, suboccipital, and orbital windows to insonify vessels including the middle cerebral, anterior cerebral, posterior cerebral, vertebral, and basilar arteries. TCD provides valuable information about cerebrovascular hemodynamics, detection of stenosis or occlusion, monitoring of vasospasm, assessment of collateral flow, and evaluation of embolic phenomena. The technique is particularly useful in stroke evaluation, subarachnoid hemorrhage monitoring, and assessment of cerebrovascular reserve capacity.
Usage
Usage note: Commonly abbreviated as TCD; distinguish from extracranial Doppler studies.
In Context
- "Transcranial Doppler demonstrated elevated velocities in the middle cerebral artery consistent with vasospasm." — Neurovascular monitoring
- "The transcranial Doppler examination revealed microembolic signals during carotid intervention." — Procedural monitoring