Intracranial Stenosis (WASID) — free guideline decision tool
Compute intracranial arterial stenosis from diameters using the WASID method (distinct from the extracranial NASCET method).
Open guideline tool →Guideline-based
Implements the decision logic from published clinical guidelines.
Runs in your browser
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.
| Narrowest stenosis diameter (Dstenosis) | 1.0 mm |
|---|---|
| Proximal normal diameter (Dnormal) | 3.0 mm |
| Vessel | Intracranial ICA |
→WASID stenosis67% · Moderate (50–69%)
- WASID：(1 − Dstenosis/Dnormal)×100 = (1 − 1/3)×100 = 67%
- Vessel：Intracranial ICA
- Grade：Moderate (50–69%)
Common questions
What is Intracranial Stenosis (WASID)?
Compute intracranial arterial stenosis from diameters using the WASID method (distinct from the extracranial NASCET method).
How is Intracranial Stenosis (WASID) calculated? What is the core formula?
WASID = (1 − Dstenosis/Dnormal)×100, using the proximal normal segment (or distal if proximally diseased). Mild < 50%, moderate 50–69%, severe 70–99%.
When is Intracranial Stenosis (WASID) used?
Quantify intracranial large-artery stenosis to guide intensive medical therapy decisions.
What are the key clinical points for Intracranial Stenosis (WASID)?
Symptomatic 70–99% stenosis is managed primarily with intensive medical therapy. SAMMPRIS showed routine stenting is not superior to medical therapy. Choose the reference segment carefully for the basilar artery.
What are the limits and cautions when using Intracranial Stenosis (WASID)?
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 Intracranial Stenosis (WASID) calculated in practice? Can you show a worked example?
Inputs: Narrowest stenosis diameter (Dstenosis) 1.0 mm, Proximal normal diameter (Dnormal) 3.0 mm, Vessel Intracranial ICA → Result: WASID stenosis 67 % · Moderate (50–69%)（WASID: (1 − Dstenosis/Dnormal)×100 = (1 − 1/3)×100 = 67%, Vessel: Intracranial ICA, Grade: Moderate (50–69%)）
Run Intracranial Stenosis (WASID) now
Compute intracranial arterial stenosis from diameters using the WASID method (distinct from the extracranial NASCET method).
Open guideline tool →For licensed clinicians. Not a substitute for clinical judgement.
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