Transcranial Doppler

Transcranial doppler (TCD) is a valuable tool for the bedside evaluation of major intracranial vessels, including arteries of the circle of Willis. Introduced in clinical practice by Rune Aaslid and colleagues [1], TCD is a reliable, noninvasive, real-time technique, allowing dynamic monitoring of the cerebral blood flow (CBF) velocity. TCD relies on the pulsed-wave Doppler technique to insonate cerebral vessels and evaluate red blood cell (RBC) velocity inside the vessel. In current clinical practice, it is commonly used in conditions like stroke, traumatic brain injury (TBI), and aneurysmal subarachnoid hemorrhage (aSAH) [2–4]. This chapter discusses the principle, technique, clinical applications, and the limitations of TCD in detail.