Departments of Diagnostic Radiology, Clinique St Luc, 5004, Bouge, Namur, Belgium.
Surg Radiol Anat. 2021 Mar;43(3):417-426. doi: 10.1007/s00276-020-02661-x. Epub 2021 Jan 23.
To confirm and illustrate the great variability of morphology of the Cerebral Arterial Circle (CAC)-also commonly called "Circle of Willis"-in current clinical Computed Tomography Angiography (CTA) practice.
Computed Tomographic Angiographic 3D Volume Rendering reconstructions of the CAC performed in a series of 511 patients were retrospectively reviewed and classified following their anatomic configuration.
An amount of 27 CAC configurations were listed. Complete and "nearly complete" (1 missing segment) CACs were found in 115 (22.58%) and 157 (28.6%) patients. The posterior arch was much more frequently incomplete (374 patients = 73.18%) than the anterior arch (96 patients = 18.4%). The main cause was a high prevalence of missing posterior communicating arteries (PCoAs). The left or right PCoA were unilaterally lacking in 156 patients (30.53%) and both PCoAs were lacking in 179 patients (35.02%). Cases with 2 and 3 missing segments were observed in 184 (36%) and 44 patients (8.6%). Precarious situations were also identified including 7 cases (1.4%) of complete isolation of the middle cerebral artery (MCA), 11 cases (2.15%) of absence of interhemispheric supply, 205 cases (40.1%) of full separation of the carotid and vertebra-basilar (VB) territories and 44 cases (8.6%) of full separation of the three main arterial axes (both ICAs and VB). The prevalence of Fetal Posterior Cerebral Arteries (FPCA) variants was also reported. A "Full" FPCA was found unilaterally in 48 (9.4%) and bilaterally in 13 (2.54%) of patients. Apart from agenesis and hypoplasia reported in our study, various other variations of the anterior complex of the CAC (ACoA and A2 segments of the ACA) were also noted.
CTA with 3D Volume Rendering may powerfully assess the numerous variations of the CAC. This assessment is of prime importance for the evaluation of patients presenting with risk factors or in whom neurosurgery, cardiac surgery, interventional radiology or carotid endarterectomy (CEA) are being considered.
在当前临床计算机断层血管造影术（CTA）实践中，证实并阐明大脑动脉环（CAC）-通常也称为“Willis 环”-形态的巨大变异性。
回顾性分析了 511 例患者的 CAC 计算机断层血管造影三维容积重建，并根据其解剖结构进行分类。
列出了 27 种 CAC 构型。115 例（22.58%）和 157 例（28.6%）患者存在完整和“几乎完整”（1 个缺失节段）CAC。后弓明显比前弓更常不完整（374 例=73.18%）。主要原因是后交通动脉（PCoA）缺失的高患病率。156 例（30.53%）患者单侧缺少左或右 PCoA，179 例（35.02%）患者双侧 PCoA 缺失。184 例（36%）和 44 例（8.6%）患者存在 2 个和 3 个缺失节段。还确定了不稳定情况，包括 7 例（1.4%）大脑中动脉（MCA）完全孤立、11 例（2.15%）半球间供应缺失、205 例（40.1%）颈内动脉和椎基底动脉（VB）完全分离以及 44 例（8.6%）3 个主要动脉轴（颈内动脉和椎基底动脉）完全分离。还报告了胎儿后大脑动脉（FPCA）变异的流行情况。48 例（9.4%）单侧出现“完全”FPCA，13 例（2.54%）双侧出现。除了本研究报告的发育不全和发育不良外，还注意到 CAC 前复合体（ACA 的 ACoA 和 A2 段）的各种其他变异。
CTA 结合三维容积重建可以有力地评估 CAC 的众多变化。这种评估对于评估有风险因素的患者或考虑神经外科、心脏外科、介入放射学或颈动脉内膜切除术（CEA）的患者非常重要。
