Transcranial Doppler (TCD) uses ultrasound through thin areas of the skull to measure the speed of blood flow in the major arteries of the brain. It is non-invasive, portable and radiation-free.
Uses
- Narrowing of brain arteries and stroke evaluation
- Vasospasm monitoring after subarachnoid haemorrhage
- Detection of micro-emboli and right-to-left shunt (bubble study / PFO)
- Screening children with sickle cell disease
- Assessment of collateral circulation with carotid disease
Preparation
No special preparation is required. Avoid hair oil on the day of the test.
Frequently asked questions about Transcranial Doppler (TCD)
Is TCD the same as a carotid Doppler?
No. Carotid Doppler studies the arteries in the neck; TCD studies the arteries inside the skull. They are often done together.
Page reviewed by the radiology team at Kansal Diagnostic Centre · Updated October 2026