🧠 PHASES Score (5-year aneurysm rupture risk)
Estimate the 5-year rupture risk of an unruptured intracranial aneurysm with the PHASES score.
Standalone discrimination is limited — combine with ELAPSS, vessel-wall imaging and morphology.
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When to use
Weigh observation vs intervention for unruptured intracranial aneurysms.
How it works
Points from Population, Hypertension, Age ≥ 70, Size, Earlier SAH and Site. Total maps to an approximate 5-year rupture risk (0.4% at low scores to ~ 17.8% at ≥ 12).
Key points
- Standalone discrimination is limited — combine with ELAPSS, vessel-wall imaging and morphology.
- Derived from North American/Finnish/Japanese cohorts; no China-specific term.
- Use for direction, not as a sole treatment trigger.
References
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Population | North America/Europe (non-Finnish) · China/other (baseline 0) |
|---|---|
| Hypertension | No |
| Age | < 70 y |
| Maximum aneurysm diameter | < 7 mm |
| Earlier SAH (from a different aneurysm) | No |
| Site | ICA |
→PHASES total0 · 5-yr rupture risk ≈ 0.4%
- Population P：North America/Europe (non-Finnish) +0
- Hypertension H：No 0
- Age A：< 70 0
| Population | Finnish |
|---|---|
| Hypertension | Yes |
| Age | ≥ 70 y |
| Maximum aneurysm diameter | ≥ 20 mm |
| Earlier SAH (from a different aneurysm) | Yes |
| Site | ACA/Pcom/posterior circulation |
→PHASES total22 · 5-yr rupture risk ≈ 17.8%
- Population P：Finnish +5
- Hypertension H：Yes +1
- Age A：≥ 70 +1
Frequently asked questions
- What is PHASES Score (5-year aneurysm rupture risk)?
- Estimate the 5-year rupture risk of an unruptured intracranial aneurysm with the PHASES score.
- How is PHASES Score (5-year aneurysm rupture risk) calculated? What is the core formula?
- Points from Population, Hypertension, Age ≥ 70, Size, Earlier SAH and Site. Total maps to an approximate 5-year rupture risk (0.4% at low scores to ~ 17.8% at ≥ 12).
- When is PHASES Score (5-year aneurysm rupture risk) used?
- Weigh observation vs intervention for unruptured intracranial aneurysms.
- What are the key clinical points for PHASES Score (5-year aneurysm rupture risk)?
- Standalone discrimination is limited — combine with ELAPSS, vessel-wall imaging and morphology. Derived from North American/Finnish/Japanese cohorts; no China-specific term. Use for direction, not as a sole treatment trigger.
- What are the limits and cautions when using PHASES Score (5-year aneurysm rupture risk)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is PHASES Score (5-year aneurysm rupture risk) calculated in practice? Can you show a worked example?
- Inputs: Population North America/Europe (non-Finnish) · China/other (baseline 0), Hypertension No, Age < 70 y, Maximum aneurysm diameter < 7 mm, Earlier SAH (from a different aneurysm) No, Site ICA → Result: PHASES total 0 · 5-yr rupture risk ≈ 0.4%（Population P: North America/Europe (non-Finnish) +0, Hypertension H: No 0, Age A: < 70 0） Inputs: Population Finnish, Hypertension Yes, Age ≥ 70 y, Maximum aneurysm diameter ≥ 20 mm, Earlier SAH (from a different aneurysm) Yes, Site ACA/Pcom/posterior circulation → Result: PHASES total 22 · 5-yr rupture risk ≈ 17.8%（Population P: Finnish +5, Hypertension H: Yes +1, Age A: ≥ 70 +1）