Small ruptured cerebral aneurysms-do they rupture on formation or not?

The theory that nearly all cases of subarachnoid haemorrhage due to small aneurysms occur as a result of aneurysm formation, and rupture over a short time period is incorrect. Our findings indicate that at least half of all subarachnoid haemorrhage cases arise from the population harbouring small aneurysms as a pre-existing condition.