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Small ruptured cerebral aneurysms-do they rupture on formation or not?
Ben McGuinness1, Nicholas Chieng2, Connor Skipworth2
1Radiology Department, Auckland City Hospital, 2 Park Road, Grafton, Auckland, New Zealand. benm@adhb.govt.nz.
Neuroradiology
|September 30, 2021
Summary
Most subarachnoid hemorrhages result from small aneurysms. Contrary to popular belief, these aneurysms are often detectable on prior imaging, indicating they pre-exist rupture, not form rapidly.
Area of Science:
- Neurology
- Neurosurgery
- Radiology
Background:
- Subarachnoid hemorrhage (SAH) is frequently caused by the rupture of small cerebral aneurysms.
- A prevailing hypothesis suggests these aneurysms form and rupture rapidly within days to weeks.
Purpose of the Study:
- To evaluate the hypothesis that small aneurysms causing SAH are not discoverable as pre-existing conditions on prior medical imaging.
- To determine if small aneurysms are typically pre-existing or rapidly formed before rupture.
Main Methods:
- Retrospective review of 851 patients with SAH due to small cerebral aneurysms over 11 years.
- Analysis of prior imaging studies in 35 patients for the presence of the index aneurysm.
Main Results:
- In 18 of 35 patients (51%) with prior imaging, the small aneurysm was identified as a pre-existing, unruptured condition.
- The median interval between prior imaging and SAH was 31 months.
Conclusions:
- The hypothesis of rapid aneurysm formation and rupture is incorrect.
- At least half of SAH cases arise from pre-existing small aneurysms detectable on prior imaging.
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