| Vasospasm | Mean Velocity | MCA/ICA Mean Velocity Ratio |
|---|---|---|
| Normal | 30 — 80 cm/s | |
| Hyperemia | 120 — 140 cm/s | < 3.0 |
| Moderate | 140 — 200 cm/s | 3.0 — 6.0 |
| Severe | > 200 cm/s | > 6.0 |
Daigle, R (2009). Techniques in noninvasive vascular diagnosis: An encyclopedia of vascular testing 3rd edition. Littleton, CO: Summer Publishing.