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Updated: Aug 20, 2026

A Murine Model of Carotid Aneurysm Formation
Published on: September 9, 2025
The natural history of unruptured intracranial aneurysms
J Mocco1, Ricardo J Komotar, Sean D Lavine
1Department of Neurological Surgery, Columbia University, New York, New York 10032, USA.
Abstract:
Since the publication of preliminary results from the International Study of Unruptured Intracranial Aneurysms in 1998 there has been a great deal of debate concerning the natural history of these lesions and their attendant risk of aneurysmal subarachnoid hemorrhage. Therefore, the authors reviewed a selected number of crucial studies concerning this topic to determine the best evidence-based estimate of a rupture rate for these lesions. Based on this analysis, the yearly risk of bleeding for an unruptured intracranial aneurysm is estimated to be approximately 1% for aneurysms 7 to 10 mm in diameter. This risk of rupture increases with aneurysm size and it likewise diminishes as the size of the lesion decreases. This general rule serves as a reasonable interpretation of the results reported in the current body of literature.
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