| Sickle Cell | |
|---|---|
| Normal | < 170 cm/second |
| Conditional | ≥ 170 cm/second, but < 200 cm/second |
| Abnormal | ≥ 200 cm/second |
Velocity criteria apply to all vessels within the circle of Willis.
1. Adams et al. Stroke Prevention Trial in Sickle Cell Anemia (STOP): Study Design. Controlled Clinical Trials. 1998;19:110-129.
2. Adams et al. Discontinuing Prophylactic Transfusions Used to Prevent Stroke in Sickle Cell Disease. The New England Journal of Medicine. 2005;353:2769-2778.
3. Lonergan et al. Sickle Cell Anemia. RadioGraphics. 2001;21:971-994.