Illustrative image of an infundibulum of the PCoA.In the case of such aneurysm-like structures (red arrowhead), a junctional dilation (or infundibulum) is highly suspected as opposed to an aneurysm, because the PCoA is visible (yellow arrowhead). This lesion is not included as a suspicious aneurysm in the study. PCoA, posterior communicating artery.