Bleed rates (%) from numerical data in 2003 ISUIA calculated as annual bleed risk rounded to two significant figures
| <7 mm | 7–12 mm | 13–24 mm | >24 mm | ||
|---|---|---|---|---|---|
| Incidental | Additional | ||||
| AC, anterior communicating; IC internal carotid; MC, middle cerebral; P, posterior circulation; PC posterior communicating. | |||||
| Cavernous carotid | 0 | 0 | 0 | 0.61 | 1.3 |
| AC/MC/IC | 0 (0.08 if posterior communicating artery included) | 0.30 | 0.53 | 3.1 | 9.7 |
| PC/P | 0.51 | 0.67 | 3.1 | 4.0 | 13 |