Table 1.
PHASES aneurysm risk score [11].
| Population | |
| North American or European (except Finnish) | 0 point |
| Japanese | 3 points |
| Finnish | 5 points |
| Hypertension | |
| No | 0 point |
| Yes | 1 point |
| Age | |
| Less than 70 years | 0 point |
| Greater than or equal to 70 years | 1 point |
| Size of aneurysm | |
| Less than 7.0 mm | 0 point |
| 7.0 mm–9.9 mm | 3 points |
| 10.0 mm–19.9 mm | 6 points |
| Greater than or equal to 20 mm | 10 points |
| Earlier subarachnoid hemorrhage from another aneurysm | |
| No | 0 point |
| Yes | 1 point |
| Site of aneurysm | |
| Internal carotid artery | 0 point |
| Middle cerebral artery | 2 points |
| Others like anterior cerebral artery, posterior communicating | 4 points |
| artery, or posterior circulation aneurysms | |
| PHASES risk score | 5-year risk of aneurysm rupture |
| Less than or equal to 2 | 0.4% |
| 3 | 0.7% |
| 4 | 0.9% |
| 5 | 1.3% |
| 6 | 1.7% |
| 7 | 2.4% |
| 8 | 3.2% |
| 9 | 4.3% |
| 10 | 5.3% |
| 11 | 7.2% |
| Greater than or equal to 12 | 17.8% |