Analysis of 179 posterior communicating artery infundibular dilations demonstrating low risk for transformation to aneurysm or rupture and the usefulness of the “round defect”

• Published in: Clinical neurology and neurosurgery 2024-11, Vol.246, p.108601, Article 108601
• Main Authors: Blitz, Sarah E., Gelman, Justin, Chalif, Joshua I., Altshuler, Marcelle S., Dmytriw, Adam A., Du, Rose
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aneurysm; Aneurysm, Ruptured - diagnostic imaging; Aneurysms; Blebs; Carotid arteries; Carotid artery; Carotid Artery, Internal - diagnostic imaging; Connective tissue; Connective tissue disease; Connective tissue diseases; Dilatation, Pathologic - diagnostic imaging; Female; Humans; Intracranial Aneurysm - diagnostic imaging; Kidney diseases; Magnetic Resonance Imaging; Male; Medical history; Medical imaging; Middle Aged; Patients; Polycystic kidney; Posterior communicating artery infundibulum; Rupture; Tomography, X-Ray Computed; Veins & arteries
• ISSN: 0303-8467; 1872-6968; 1872-6968
• DOI: 10.1016/j.clineuro.2024.108601

Outpouchings, particularly those originating from the posterior communicating artery off the internal carotid artery (Pcom-Ops), are often unable to be categorized definitively as aneurysms or infundibula resulting in frequent clinical imaging and follow-up. We aimed to investigate potential correlations between growth and rupture rates and easily definable imaging characteristics in Pcom-Ops. We analyzed CT and MR imaging of Pcom-Ops identified in a case series of patients seen between 2007 and 2022. For each outpouching, the length of the base, hypotenuse, and round defect, defined as the deviation from triangular shape, were calculated. These measurements were used to estimate the conical volume and eccentricity of the Pcom-Op. 179 Pcom-Ops were identified from 152 patients who were followed for an average of for 3.2 ± 3.2 years. Bilateral Pcom-Ops were present in 17.8 % patients and 7.2 % had an underlying connective tissue disease. Only one Pcom-Op in a patient with polycystic kidney disease subsequently became a clear aneurysm after 6.3 years. The average approximated volume and round defect at presentation were 2.3 ± 2.2 mm3 and 0.29 ± 0.16 mm, respectively. Volume and round defect changed minimally over time followed. Outlier analysis of round defect, determined by Z-score more than 3 standard deviations above the mean, was not associated with evolution into clear aneurysms. Pcom-Ops rarely enlarge or rupture. Pcom-Op eccentricity does not predict high risk Pcom-Ops. Thus Pcom-Ops in general may not require close follow-up over time. However, Pcom-Ops in patients with connective tissue diseases should be monitored more closely. •Posterior communicating artery outpouchings are often unable to be categorized definitively as aneurysms or infundibula.•Posterior communicating artery outpouchings rarely enlarge or rupture.•Posterior communicating artery outpouchings eccentricity does not predict high risk posterior communicating artery outpouchings.•Posterior communicating artery outpouchings in general may not require close follow-up over time.•Posterior communicating artery outpouchings in patients with connective tissue diseases should be monitored more closely.