Objective:

To investigate whether the status of Mirror Intracranial Aneurysms (MIAs) is associated with higher patient-level event rates and to assess the independent risk of rupture after accounting for aneurysm multiplicity.

Key Findings:

• MIAs occur bilaterally on corresponding arteries and are associated with a significantly higher risk of rupture.
• Morphological parameters such as size ratio and aspect ratio are significant predictors of aneurysm rupture.
• Aneurysm multiplicity, including MIAs, raises the risk of UIA rupture, highlighting the need for careful monitoring.

Interpretation:

The study suggests that MIAs may represent a unique risk category for rupture due to their anatomical clustering and associated hemodynamic factors, which could influence treatment decisions.

Limitations:

• Retrospective design may introduce selection bias, potentially affecting the generalizability of the findings.
• Potential classification bias despite high inter-rater reliability.
• Data collection limited to specific imaging modalities and timeframes, which may not capture all relevant clinical scenarios.

Conclusion:

MIAs may pose a higher risk for adverse outcomes compared to non-MIAs, warranting further investigation into their management and treatment strategies, including prospective studies.