Table 2 Middle cerebral artery criteria of angiographic vasospasm by transcranial Doppler ultrasonography
From: Aneurysmal subarachnoid haemorrhage from a neuroimaging perspective
| Â | Mean flow velocity (cm/second) | Hemispheric ratio (Lindegaard ratio) |
|---|---|---|
Normal values | 35 to 89 | <3 |
Above normal values | 90 to 119 | – |
Mild vasospasm | 120 to 150 | 3 to 4 |
Moderate | 150 to 199 | 4 to 5.9 |
Severe | ?200 | ?6 |