The circle of Willis (CW) located at the base of the brain forms an important collateral network to maintain adequate cerebral perfusion, especially in clinical situations requiring compensatory changes in blood flow. Morphopathological changes in the CW may relate to the severity of the symptoms of certain neurodegenerative and cerebrovascular disorders. The purpose of this study was to investigate the CW abnormalities and their clinical importance in ageing brains. The CW was examined macroscopically in 73 formalin-fixed samples to determine the degree of stenosis of each CW component, atherosclerosis of the CW, hypoplasia (threshold diameter <1 mm), anatomical variations and aneurysms. Age-related neurodegenerative and cerebrovascular pathologies were screened using immunohistopathological techniques on specific neuroanatomical regions based on standard guidelines. The majority of the elderly brains - 93% (68/73) presented at least a single hypoplastic CW component at death. Anatomical variations were mostly identified in communicating arteries, followed by proximal posterior and anterior cerebral arteries. Arterial bifurcations were found to be the predominant sites for cerebral aneurysms. More than 90% of the elderly brains presented CW atherosclerosis at death. CW abnormalities did not show any strong associations with neurodegenerative pathologies except for an "at risk" significant association observed between Braak's neurofibrillary tangle (NFT) stages 1-VI and CW atherosclerosis grades ≥ mild (p = 0.05). However, a significant association was observed between microscopic infarcts in deep white matter and hypoplasia in communicating arteries with Fisher's exact test (p < 0.05). Overall, CW abnormalities were predominant in the ageing brains, however their relationships to the occurrence and severity of the symptoms of neurodegenerative pathologies were found to be low.

中文翻译：

---

Willis 环异常及其在衰老大脑中的临床重要性：尸体解剖学和病理学研究

位于大脑底部的威利斯环 (CW) 形成了一个重要的侧支网络，以维持足够的脑灌注，尤其是在需要血流代偿性变化的临床情况下。CW 的形态病理学变化可能与某些神经退行性疾病和脑血管疾病症状的严重程度有关。本研究的目的是调查 CW 异常及其在衰老大脑中的临床重要性。在 73 个福尔马林固定样本中对 CW 进行宏观检查，以确定每个 CW 组件的狭窄程度、CW 的动脉粥样硬化、发育不全（阈值直径 <1 毫米）、解剖变异和动脉瘤。根据标准指南，使用免疫组织病理学技术在特定神经解剖区域筛选与年龄相关的神经退行性和脑血管病变。大多数老年人脑 - 93% (68/73) 在死亡时至少表现出单个发育不良的 CW 成分。解剖变异主要在交通动脉中发现，其次是大脑后动脉和大脑前动脉近端。发现动脉分叉是脑动脉瘤的主要部位。超过 90% 的老年人大脑在死亡时呈现 CW 动脉粥样硬化。除了在 Braak 神经原纤维缠结 (NFT) 1-VI 期和 CW 动脉粥样硬化等级 ≥ 轻度 (p = 0.05) 之间观察到的“有风险”显着关联之外，CW 异常并未显示出与神经退行性疾病的任何强关联。然而，使用 Fisher 精确检验观察到深部白质中的微观梗塞与交通动脉发育不全之间存在显着关联（p < 0.05）。总体而言，CW 异常在老化的大脑中占主导地位，但发现它们与神经退行性疾病症状的发生和严重程度的关系较低。