The Infundibulum-Aneurysm Conundrum: A Longitudinal Single-Center Analysis.

Area of Science:

• Neuroradiology
• Cerebrovascular imaging
• Medical diagnostics

Background:

• Intracranial infundibula are common vascular findings.
• Distinguishing infundibula from small aneurysms can be challenging.
• Variability in diagnostic labeling impacts patient management.

Purpose of the Study:

• To characterize the natural history of intracranial infundibula.
• To evaluate diagnostic variability in lesions labeled "aneurysm vs infundibulum".
• To identify predictors of diagnostic ambiguity.

Main Methods:

• Retrospective analysis of 665 intracranial outpouchings (CTA, MRA, DSA).
• Classification into unequivocal infundibula (n=321) and "aneurysm vs infundibulum" conundrums (n=344).
• Review of follow-up imaging for stability and reassessment of selected cases.

Main Results:

• No complications or morphological changes observed in either group over medium-term follow-up.
• Conundrums were more likely to undergo follow-up imaging (p<0.001).
• Non-Pcomm location and comorbid aneurysms predicted conundrum labeling; reassessment showed high concordance with DSA.

Conclusions:

• Both infundibula and conundrums demonstrated stability, suggesting low biological risk.
• Diagnostic uncertainty is primarily due to interpretive variability.
• Structured reporting and location-based heuristics can minimize unnecessary surveillance.