PURPOSE The intracranial arterial vasculature has numerous anatomical variants, which vary from largely benign to having remarkable clinical implications. The significance of a lesser known variant described as a junctional dilatation of the basilar artery tip has not yet been described in the literature. METHODS Retrospective query of radiology imaging reports was performed for vascular specific imaging of the head, which included descriptions related to the basilar junctional dilatation variant from 2005 to 2019 at a single institution. Imaging studies were individually scrutinized for true presence of the variant, and were assessed for any change in appearance over time. Primary data-points collected included length of time between imaging studies with stable appearance, intracranial aneurysm incidence, and frequency of hemorrhage associated with aneurysm rupture. RESULTS Fifty patients with multiple vascular exams were found to have the typical appearance of the basilar junctional dilatation variant. The variant was found to be stable over time in all patients, without interval expansion or basilar tip aneurysm development. Interval follow-up ranged from 1 to 156 months, with a mean follow-up length of 3.83 years, and total patient-years of follow-up of 192. No adverse neurological events were found which could be attributed to the basilar junctional dilatation variant. CONCLUSION Junctional dilatation of the basilar artery tip is a benign, normal variant of the posterior intracranial arterial circulation. It is important for both radiologists and clinicians to recognize its characteristic appearance and benign nature, as misdiagnosis may lead to unnecessary work-up, imaging, and/or treatment.

中文翻译：

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基底尖端交界处扩张：具有良性自然病程的正常解剖变异

目的 颅内动脉血管系统有许多解剖变异，从大部分良性到具有显着临床意义不等。文献中尚未描述被描述为基底动脉尖端交界处扩张的鲜为人知的变异的重要性。方法 对头部血管特异性影像学影像学报告进行回顾性查询，其中包括与 2005 年至 2019 年在单个机构的基底交界处扩张变异相关的描述。对影像学研究进行单独审查以确认变异的真实存在，并评估外观随时间的任何变化。收集的主要数据点包括具有稳定外观的影像学研究之间的时间长度、颅内动脉瘤发生率、以及与动脉瘤破裂相关的出血频率。结果 50 名接受多次血管检查的患者被发现具有基底交界处扩张变异的典型表现。发现该变异在所有患者中随着时间的推移保持稳定，没有间隔扩张或基底尖端动脉瘤发展。间隔随访时间为 1 至 156 个月，平均随访时间为 3.83 年，总随访患者年数为 192 年。未发现可归因于基底交界处扩张变异的不良神经系统事件. 结论 基底动脉尖端的交界处扩张是颅内后动脉循环的良性、正常变异。放射科医生和临床医生都必须认识到其特征性的外观和良性，