J Neuroradiology
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Between 3.6 and 6% of the population harbour an unruptured intracranial aneurysm. Risk of rupture is related to aneurysm site and size and whether or not the patient has already had a subarachnoid haemorrhage (SAH) from another aneurysm. In ISUIA 2, the rupture rate for anterior circulation aneurysms<7mm was 0% per year in patients with no prior SAH, and 0.3% per year in patients with previous SAH; 7-12mm aneurysms, 0.5% per year (both groups); 13-24mm aneurysms, 3% per year; and giant aneurysms 8% per year. ⋯ There is an increased risk of SAH in relatives of patients with SAH (highest in those with two or more first degree relatives affected), but most SAH is sporadic and therefore the balance of available evidence indicates that mass screening for aneurysms is not cost effective. There may be a limited role for investigation of high-risk subgroups and ideally such screening should be tested in a randomised trial. The avoidance and active management of vascular risk factors should also be part of the management of at risk subjects.