What are the TCD criteria for evidence of middle cerebral artery vasospasm?
The main criteria for vasospasm are as follows:
- Mean middle cerebral artery (MCA) blood flow velocity >200 cm/s;
- Rapid rise (>50 cm/s) between serial TCD measurements within 24 to 48 hours; and
- Lindegaard index (MCA/ICA [intracranial artery] ratio) >6.
