Todd Stuart Miller MD, Presenter: Nothing to Disclose

Judah Burns MD, Abstract Co-Author: Nothing to Disclose

David D. Pasquale MD, Abstract Co-Author: Nothing to Disclose

Joaquim Manuel Farinhas MD, Abstract Co-Author: Nothing to Disclose

Kristopher A. Huston, Abstract Co-Author: Nothing to Disclose

Pouyan Golshani MD, MA, Abstract Co-Author: Nothing to Disclose

Allan L. Brook MD, Abstract Co-Author: Advisor, CareFusion Corporation

Jacqueline Anne Bello MD, Abstract Co-Author: Nothing to Disclose

The purpose of this analysis was to compare the observed rate of rupture of cerebral aneurysms to the estimated prevalence of small aneurysms in the same geographic population to calculate a true rupture rate.

Single institution, seven year retrospective data on ruptured cerebral aneurysms. In the same geographic population the incidence of cerebral aneurysms was determined by reviewing 15,000 MRA reports, 3000 CTA reports, and 3000 cerebral angiogram reports. Geographic origin was identified by patient zip code. Total population was estimated from 2010 US census data. Reports were analyzed for impression stating an aneurysm was present or suspected. In those cases the images were reviewed by board certified neuroradiologists specializing in cerebrovascular disease. Aneurysm data was collated by size, location, and patient age.

270 CT or LP and angiographically confirmed aneurysmal subarachnoid hemorrhages were identified. 553 unruptured aneurysms were identified from 2340 cerebral angiograms, 15763 MRA, 2526 CTAs during the same time period in unique patients from the same zip codes. The adult population of the affected zip code region is 1,000,000. Based on previously published data, a 3% prevalence rate was assumed. Based on ISUIA data, a 0.05%/year rupture rate was assumed. This would yield an expected aneurysm prevalence of 30,000 with a conservative expected aneurysm rupture rate is 15 per year for small anterior circulation aneurysms in a population without history of rupture. The observed annual rupture rate was 45 in the study region. The observed prevalence in the study population was 553/18249 or 3%.  

Although the most widely quoted prospective study on risk of aneurysm rupture indicates a rate of rupture of small aneurysms of 0.01% per year, our local experience indicated a higher risk of rupture.

Incidentally detected small cerebral aneurysms may pose a greater risk of rupture than has been previously suspected, and observation may not be appropriate.

Miller, T, Burns, J, Pasquale, D, Farinhas, J, Huston, K, Golshani, P, Brook, A, Bello, J, Small Cerebral Aneurysms Rupture: A Retrospective Population-based Analysis of 20,000 Neurovascular Imaging Studies.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12027706.html