Synopsis
Interpret carotid duplex findings in clinical context, recognise technical limitations, and choose timely confirmatory imaging when management depends on accuracy.
- New weakness, aphasia or visual loss remains a stroke emergency; duplex does not replace immediate brain imaging and reperfusion assessment.
- Report urgent symptomatic stenosis promptly, including side, symptom concordance, measurement convention, technical limitations and whether confirmatory imaging is needed.
- Use a NASCET-equivalent assessment for intervention decisions: 50–69% is moderate and 70–99% severe, while complete occlusion is a separate category.
Key red flags
A new focal neurological deficit during or after assessment requires immediate stroke-pathway escalation rather than completion of routine vascular testing.
A high-grade symptomatic lesion with stable non-disabling neurology requires urgent specialist communication because intervention benefit declines with delay.
Apparent severe stenosis with distal collapse, very low flow or discordant findings may be near-occlusion or occlusion and should not be graded from velocity alone.
A threadlike distal ICA or unexpectedly low variable velocity despite extreme narrowing requires angiographic clarification rather than ordinary velocity grading.
Investigation priorities
Locate plaque, estimate lumen and identify disturbed flow
Management branches
A complete carotid duplex report is available for clinical interpretation
- Confirm the indication, symptom side and timing before looking at the percentage so clinical urgency is framed correctly.
- Check that common, internal, external carotid and vertebral arteries were surveyed and note any unexamined or obscured segment.