For educational and reference use only. These calculators do not replace clinical judgement, local protocols, or a qualified clinician. Verify every result independently before it informs patient care.
Neuroradiology
Carotid Stenosis (NASCET / ECST)
Percentage internal carotid artery stenosis. NASCET uses the distal normal ICA as the reference; ECST uses the estimated original lumen at the stenosis. Both use: stenosis % = (1 − residual lumen ÷ reference) × 100.
Result
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Enter all values to calculate.
Formula
Stenosis % = (1 − residual lumen ÷ reference diameter) × 100.
References
Disclaimer
NASCET and ECST give different values for the same stenosis and are not interchangeable. Near-occlusion with luminal collapse invalidates the ratio. Correlate with velocity criteria and symptom status.
For educational and reference use only. These calculators do not replace clinical judgement, local protocols, or a qualified clinician. Verify every result independently before it informs patient care.
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