The TCD Pulsatility Index (PI) is a parameter used in Transcranial Doppler (TCD) ultrasonography to evaluate the resistance to blood flow in cerebral vessels. It’s commonly used to assess cerebral hemodynamics, especially in patients with conditions like stroke, traumatic brain injury, hydrocephalus, and brain death.

📌 Clinical Uses of PI in TCD:

• Elevated ICP (Intracranial Pressure): Higher PI suggests rising ICP.
• Vasospasm detection in subarachnoid hemorrhage.
• Brain death evaluation: Very high PI or absent diastolic flow.
• Monitoring cerebral autoregulation.
• Hydrocephalus assessment.