Blood flow reduction secondary to significant internal carotid artery (ICA) stenosis requires compensation to maintain adequate cerebral perfusion primarily through the circle of Willis (CoW). The prevalence of hypoplastic or non-visualized CoW segments was reported higher in patients with transient ischemic attack (TIA) or ischemic stroke due to carotid artery disease [1-6]. On the contrary, subjects with adequate collaterals supplying the operative side were less prone to perioperative stroke [7-10]. In a meta-analysis significant positive relationship was found between vulnerable plaque features and cerebral ischemia...

Study Group After Institutional Review Board approval and informed consent from all study subjets, we analyzed the carotid CT angiography (CTA) and brain MRI of 72 patients who underwent carotid endarterectomy between January 2016-May 2017. The inculsion criteria were adequate CTA covering the whole CoW and brain MRI. Procedures were in accordance with institutional guidelines. CTA Examinations All CTA examinations were performed on Brilliance iCT 256 (Philips Healthcare, Best, The Netherlands) from the aortic arch to the vertex with field of view 180-200 mm collimation...

Demographics, cardiovascular risk factors, plaque morphology, degree ofICA stenosis and percentage of cerebral ischemia in different configurations of Circle of Willis are reported in Table 2. Table 2. Variable Overall n = 72 CompleteCoW (Normal or hypoplastic) n = 26 Incomplete CoW n = 46 p-value Demographics Male gender 45 (63%) 18 (69%) 27 (59%) 0.375 Age ± SD (years) 66 ± 17 66 ± 12 67 ± 9 0.076 Symptomatic 17 (24%) 4 (15%) 13 (28%) 0.217 Perioperative ischaemia 5 (7%) 1 (4%) 4...

Our major finding was the higher prevalence of recentor chronic ipsilateral ischemia in incomplete CoW. In patients with atherosclerotic ICA disease, incompleteness of the CoW was associated with higher risk of TIA and ischemic stroke [1, 2]. Our previous study showed significant positive association between brain infarcts on CT and CoW with ≥2 non-visualized segments in a cohort of 544 [3]. This is in agreement with the current study, which included FLAIR and DWI-MRI, the most sensitive method for ischemia detection, also suggesting significant correlation...

1. Henderson RD, Eliasziw M, Fox AJ, Rothwell PM, Barnett HJ (2000) Angiographically defined collateral circulation and risk of stroke in patients with severe carotid artery stenosis. North American Symptomatic Carotid Endarterectomy Trial (NASCET) Group. Stroke 31:128-132 ADDIN EN.REFLIST 2. Hedera P, Bujdakova J, Traubner P, Pancak J (1998) Stroke risk factors and development of collateral flow in carotid occlusive disease. Acta Neurol Scand 98:182-186 3. Varga A, Di Leo G, Banga PV et al (2018) Multidetector CT angiography of the Circle of Willis: association...