NASCET Carotid Stenosis Calculator
Enter the narrowest lumen and the distal normal ICA diameter (mm or cm). Results update automatically when both fields are entered.
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Computed NASCET %:
Formula used: (1 − (Dstenosis / Ddistal)) × 100
Key trial: North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. N Engl J Med. 1991;325(7):445-453. doi:10.1056/NEJM199108153250701
Imaging: This calculator uses measurements of CTA and MRA.
Why the NASCET method? (click to expand)
Disclaimer: The calculator returns a numeric NASCET percent stenosis and general severity categories only. It is not a substitute for formal radiology measurement, clinical judgement, or treatment decisions.