PHASES Score (5-year aneurysm rupture risk) — free guideline decision tool
Estimate the 5-year rupture risk of an unruptured intracranial aneurysm with the PHASES score.
Open guideline tool →Guideline-based
Implements the decision logic from published clinical guidelines.
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No installation. Enter the patient's values and get a guideline recommendation instantly.
Data stays local
Nothing is uploaded. Results are for licensed clinicians only.
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
Common 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）
Run PHASES Score (5-year aneurysm rupture risk) now
Estimate the 5-year rupture risk of an unruptured intracranial aneurysm with the PHASES score.
Open guideline tool →For licensed clinicians. Not a substitute for clinical judgement.
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