Key result
Circle of Willis variations causing internal carotid artery asymmetry were present in 8.0% of patients without steno-occlusive disease, demonstrating that these variations can mimic near-occlusion.
Why the study?
Carotid near-occlusion must be distinguished from conventional stenosis, but internal carotid artery asymmetry linked to Circle of Willis variations can mimic near-occlusion when stenosis coincides.
Cross-Sectional (n=3,989)
Yes
Internal carotid artery asymmetry associated with Circle of Willis variations is common (8% prevalence) and can mimic carotid near-occlusion, indicating that diagnosis of near-occlusion should not rely on asymmetry alone.
Requires caution interpreting carotid asymmetry as near-occlusion; leaves open whether routine Circle of Willis assessment improves diagnostic accuracy.
Differentiating carotid near-occlusion (tight atherosclerotic stenosis causing distal artery size reduction) from conventional stenosis is the first step when grading carotid stenoses with NASCET method. The internal carotid artery (ICA) can be asymmetrically associated with Circle of Willis variations. When such ICA asymmetry coincides with stenosis, it may mimic near-occlusion. We studied ICA anatomical variant prevalence in 4042 consecutive CTA exams from all indications, 53 excluded due to carotid occlusion, 814 with any ≥ 50% steno-occlusive disease intra- or extracranially, 3228 without. Of the 3989 included cases, 568 (14%) had ICA asymmetry, of which 335 (59%) were from associated with Circle of Willis variations. Of 3228 patients without ≥ 50% stenosis or other steno-occlusive disease intra- and extracranially; 257 (8.0%) demonstrated ICA asymmetry associated with Circle of Willis variations, equally common among sexes and age unrelated and most frequently attributed to an ipsilateral A1 hypoplasia/aplasia, less often attributed to large contralateral posterior communicating artery. As ICA asymmetry associated with Circle of Willis variations are common, caution should be exercised diagnosing near-occlusion on asymmetry alone.
No takes yet. Share an insight, caveat, or question.
Johansson et al. (2019) conducted a cross-sectional in Internal carotid artery asymmetry and carotid stenosis (n=3,989). Circle of Willis anatomical variations vs. Normal Circle of Willis / symmetric ICAs was evaluated on Prevalence of asymmetric ICA associated with Circle of Willis anatomical variants in patients without ≥ 50% steno-occlusive disease (95% CI 7.0-8.9). Circle of Willis variations causing internal carotid artery asymmetry were present in 8.0% of patients without steno-occlusive disease, demonstrating that these variations can mimic near-occlusion.
Synapse has enriched 4 closely related papers on similar clinical questions. Consider them for comparative context: