Prevalence of Cerebral Artery Aneurysms

The increase in using noninvasive neuroimaging modalities such as CT angiography and MR angiography in the outpatient setting has led to a marked increase in the number of truly asymptomatic, incidental unruptured intracranial aneurysms being diagnosed.

Rinkel,and colleagues, conducted the most recent review assessing the prevalence of cerebral aneurysms in 1998. After reviewing both autopsy and angiographic studies they concluded that adults with no risk factors for sub arachnoid hemorrhage (SAH) are likely to have a prevalence of approximately 2% for unruptured aneurysms with the vast majority of these aneurysms smaller than 1 cm in diameter.

The incidence of SAH is also of relevance when determining a management strategy for unruptured intracranial aneurysms, particularly when examining the reported natural history of such lesions.

Many investigators have evaluated the incidence of SAH in particular patient populations, with reported estimates as low as six per 100,000 and as high as 96 per 100,000.

Rinkel and colleagues conducted in their paper that small (=10 mm) intracranial aneurysms have an annual risk of rupture of approximately 0.7%.