Correlation between Leukoaraiosis Volume and Circle of Willis Variants

BACKGROUND AND PURPOSE: The Circle of Willis (COW) is the main collateral system between the bilateral carotid systems and the posterior circulation. COW normal variants are encountered in up to 62% of subjects. We hypothesize that, in patients with carotid artery stenosis, the presence of COW variants is a risk factor for leukoaraiosis. MATERIALS AND METHODS: Forty-seven patients (mean age 72.1 ± 9 years, males = 39) with carotid artery stenosis admitted for carotid endarterectomy were included and underwent an admission brain MRI/MRA. Two neuroradiologists evaluated the COW variants. FLAIR-leukoaraiosis lesion-volume was performed using a semiautomated segmentation technique. Mann-Whitney and Pearson correlations were conducted to identify the correlation between the FLAIR-leukoaraiosis lesion-volume and the COW variants. ROC analysis was performed to evaluate the AUC of FLAIR-leukoaraiosis lesion-volume and presence/absence of COW variants. RESULTS: Pearson correlation demonstrated that the leukoaraiosis lesion-volume is significantly associated with the COW variants number (rho = .358, P = .0215). When patients were dicotomized in two subgroups, with and without COW variants, the lesion-volume was significantly higher in the variants group (P = .0405). The ROC curve analysis showed an AUC of .688 (SE = .083, 95%CI = .525-.823) with a statistically significant P = .0225, between the presence of COW variants and the FLAIR-leukoaraiosis lesion-volume. CONCLUSION: The presence and the number of COW variants are associated with a higher leukoaraiosis volume in patients with significant internal carotid artery stenosis.