Correlation between leukoaraiosis volume and circle of Willis variants

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.

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.

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.

The presence and the number of COW variants are associated with a higher leukoaraiosis volume in patients with significant internal carotid artery stenosis.