Key result
DUS velocity metrics poorly distinguish high-grade stenosis from near-occlusion, but multivariable models achieve 0.82 AUC.
Why the study?
Carotid near-occlusion diagnosis relies on angiographic imaging, and no validated duplex ultrasound criteria exist to distinguish near-occlusion subtypes from conventional high-grade stenosis.
Does duplex ultrasound reliably distinguish carotid near-occlusion subtypes from conventional high-grade stenosis in patients with >80% NASCET stenosis?
Observational (n=78)
Blinded observers
No
Does duplex ultrasound reliably distinguish carotid near-occlusion subtypes from conventional high-grade stenosis in patients with >80% NASCET stenosis?
Effect estimate: AUC 0.82 (95% CI 0.72-0.92)
Duplex ultrasound has modest diagnostic utility for differentiating carotid near-occlusion subtypes from high-grade stenosis, with diameter-based metrics performing better than velocity-based metrics, but additional angiographic imaging remains necessary.
Caution advised for DUS carotid classification in practice; leaves open need for validated imaging protocols in research.
PURPOSE: Carotid near-occlusion (CNO) is a subtype of severe carotid stenosis characterized by partial or complete distal internal carotid artery (ICA) collapse. Its diagnosis currently relies on angiographic imaging, and no validated duplex ultrasound (DUS) criteria exist. We aimed to assess the utility of DUS in distinguishing conventional high-grade stenosis (HGS), CNO without, and CNO with full collapse. METHODS: We retrospectively included patients with > 80% NASCET stenosis on DUS (2012-2021) who underwent CTA, MRA, or DSA within 3 months. DUS parameters were compared across groups defined by angiographic classification using uni- and multivariable analyses. RESULTS: Among 78 patients, 21 had HGS, 34 CNO without, and 23 CNO with full collapse. DUS agreed with angiographic classification in 54%, with CNO without full collapse often misclassified as HGS (85%). Velocity-based DUS metrics could not reliably distinguish CNO without full collapse from HGS. However, CNO with full collapse was distinguishable based on stenotic and distal peak-systolic and end-diastolic velocities and derived ratios (AUCs 0.70-0.76). Diameter-based metrics distinguished HGS from both CNO types: distal ICA < 3.15 mm (AUC 0.79) and ICA/ECA ratio < 0.98 (AUC 0.78). Multivariable models increased discriminatory performance (AUC 0.82). CONCLUSION: Velocity-based DUS metrics cannot reliably distinguish HGS from CNO without full collapse, representing a key clinical challenge. Although DUS-derived metrics were associated with angiographically defined CNO with full collapse, overall diagnostic gain was modest and additional imaging will often remain necessary. Nevertheless, DUS remains useful for follow-up, as hemodynamic changes may indicate evolving distal collapse.
No takes yet. Share an insight, caveat, or question.
Inauen et al. (2026) conducted an observational in Severe carotid stenosis (>80% NASCET) (n=78). Duplex ultrasound (DUS) vs. Angiography (CTA, MRA, DSA) was evaluated on Discriminatory performance (AUC) of multivariable DUS models for differentiating HGS from both CNO types (AUC 0.82, 95% CI 0.72-0.92). Duplex ultrasound velocity metrics cannot reliably distinguish high-grade stenosis from near-occlusion without full collapse, though multivariable models achieved an AUC of 0.82 for differentiation.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: