Prevalence of Asymptomatic Unruptured Intracranial Aneurysms in a Southeast Asian Population.

Background: The prevalence of asymptomatic unruptured intracranial aneurysms (AUIA) in a Southeast Asian population has not been previously studied. Knowing the disease burden and population at risk can assist us in making informed decisions when managing AUIAs. We aimed to determine if the local prevalence of AUIAs differed from other populations in the published literature.

Methods: Magnetic resonance angiography radiology reports and images for 4572 patients between January 2013 and January 2014 were reviewed for AUIAs.

Results: The overall prevalence of AUIAs was 3.5% (160/4572). It was significantly higher in women (4.5%) compared with men (2.6%) (P < 0.001). The mean aneurysm size was 3.2 ± 1.7 mm. Of the aneurysms, 88.5% (146/165) measured less than 5 mm, 9.7% (16/165) measured 5-9 mm, and 1.8% (3/165) measured more than 9 mm. Most of the aneurysms were located in the cavernous segment (72/165, 43.6%) and ophthalmic segment (34/165, 20.6%) of the internal carotid artery, followed by the middle cerebral artery (16/165, 9.7%). The posterior circulation contributed 9.1% (15/165) of the AUIAs. During the study period, 1 aneurysm ruptured and the rest of the aneurysms did not show any growth.

Conclusions: In this large cohort of a Southeast Asian population, the prevalence of AUIA was 3.5%. Most of the AUIAs were less than 5 mm and did not require intervention at time of discovery and did not progress within the year of follow-up.