Evolution from an Infundibulum of the Posterior Communicating Artery to a Saccular Aneurysm

Abstract

Infundibular widening of cerebral arteries can develop into true aneurysms. Mid-term and long-term follow-up MRI (e.g., in yearly intervals) is advised for infundibula with a diameter of 3 mm or more. In patients with other aneurysm(s), with a documented de novo aneurysm formation or with a familial occurrence of aneurysms, the risk of evolution of an infundibulum to a saccular aneurysm may be increased and follow-up should be even more stringent.

Intracranial aneurysm arising from infundibular dilation

“…The nature of these dilations is a matter of discussion 1. Some authors consider an ID as a preaneurysmal lesion,2–4 while others believe that is a normal variant 3.…”

Infundibular dilations of the posterior communicating arteries: pathogenesis, anatomical variants, aneurysm formation, and subarachnoid hemorrhage

“…3 8 12–24 Thirteen of these patients were female (81.3%). The median age at the time of initial diagnosis was 38 years (range 23–55 years).…”

“…Fischer et al 3 reported a middle-aged woman who presented with SAH. While the source of hemorrhage was found to be a vertebral artery aneurysm, during the initial diagnosis a PCoA ID was also identified.…”

“…A filter was used to return only articles written in the English language. IDs were classified as types I–III, as originally described by Fischer et al 3. Type I IDs do not exhibit morphological change over a long follow-up period (suggesting that type I IDs are anatomical variants), type II IDs evolve into saccular aneurysms, and type III IDs are those that result in SAH without prior aneurysmal progression.…”

“…IDs are most commonly located at the junction of the internal carotid artery (ICA) and posterior communicating artery (PCoA), where the origin of the PCoA is seen arising from the apex of the ID 2. Other less common locations include the anterior choroidal artery, ophthalmic artery, middle cerebral artery, superior cerebellar artery (SCA), and anterior communicating artery (ACoA) 3 4. IDs are often misdiagnosed as aneurysms on non-invasive imaging, and become apparent on angiography 5.…”