Anatomic Variations in the Circle of Willis in Patients with Symptomatic Carotid Artery Stenosis Assessed with Multidetector Row CT Angiography

Abstract

Purpose: To assess the presence of anterior and posterior collateral pathways in the circle of Willis in patients with symptomatic carotid artery stenosis (SCAS) and to compare this to patients without carotid artery stenosis. Materials and Methods: Multislice CT angiography was performed in 91 patients and 91 control subjects. Using consensus reading, 2 observers evaluated the presence and diameter of the anterior communicating artery (AcomA), the A1 segments of the anterior cerebral arteries, the posterior communicating arteries (PcomA) and the P1 segments of the posterior cerebral arteries. Anterior or posterior pathways were assumed to be present if the diameter of continuous arterial segments was >1 mm; both A1 segments and AcomA anterior, and ipsilateral P1 segment and PcomA posterior. Comparison between patients and controls was performed using the χ² test. Results: In the patients we found significantly more hypoplastic (<1 mm) or invisible A1 segments (16 and 14 vs. 4 and 1, respectively, p < 0.01). The AcomA was invisible in 4 patients versus 1 control. An isolated compromised anterior pathway and a combined compromised anterior and posterior pathway occurred more frequently in the patients as compared to the controls; 9 versus 1% (p < 0.01) and 26 versus 4% (p < 0.01). Conclusion: A compromised anterior collateral pathway, usually combined with a compromised posterior pathway, occurs more frequently in patients with SCAS as compared to controls, which suggests a relation between symptomatic carotid stenosis and an incomplete circle of Willis.

Preclinical Investigations for Thrombectomy Devices—Does it Translate to Humans?

“…16,17 This progress leads to a significant reduction in the use of laboratory animals and makes the results of device testing more relevant to patients.…”

The association of the circle of Willis anomaly and risk of stroke in patients with carotid artery disease

“…In patients with symptomatic carotid artery stenosis, reduction of blood flow due to a stenotic carotid artery is compensated by the increased blood flow of the collateral system 3 . The circle of Willis is an important collateral pathway, as it can maintain blood flow from the contralateral carotid and basilar artery to the stenotic carotid artery region.…”

Circle of Willis anomalies in stroke patients related with symptomatic carotid artery disease

“…TCD ile yapılan bir çalışmada WP'u anteriyor segmentlerinde bir anomali olduğunda karotis arter hastalığına bağlı inme riskinin arttığı saptanmıştır (15). BT anjiyografi ile yakın zamanda yapılan bir diğer çalışmada, WP anomalisi ile semptomatik karotis darlığı arasında bir ilişki olduğu gösterilmiştir (1). Biz çalışmamızda olguların %79,7'sinde WP anomalisi saptadık.…”

“…Major serebral arterlerin tıkanmasında WP, kontrlateral karotis arterden ve baziler arterden stenotik sulama alanına kan taşıyarak o bölgede azalan beyin perfüzyonunun düzeltilmesinde rol oynayan en önemli kollateral sistemdir. WP' daki kollateral kan akımı, anteriyor sistemde sağ ve sol prekommünikan anteriyor serebral arterler (A1 segmenti) ve anteriyor kommünikan arter (AcomA) yoluyla, posteriyor sistemde ise ipsilateral posteriyor kommünikan arter (PcomA) ve prekommünikan posteriyor serebral arterler (P1 segmenti) yoluyla sağlanmaktadır (1). Bu özellikleri ile WP anomalilerinin karotis arter darlıklarında ve tıkanmalarında infarkt oluşumuna yada semptomların şiddetinin artışına katkıda bulunduğu düşünülmektedir.…”