Brain aneurysms of all sizes are 12 times more likely to rupture if they are growing, a new study finds.
A brain (cerebral) aneurysm occurs when a blood vessel in the brain weakens and balloons out. If it bursts, it causes a bleeding (hemorrhagic) stroke that can lead to brain damage or death.
The study included 132 women and 33 men with a total of 258 brain aneurysms that were monitored for a number of years. The patients' brains were scanned using noninvasive CT angiography every six or 12 months.
Over the study period, growth occurred in 46 (18%) of the aneurysms in 38 patients. Three of the growing aneurysms ruptured and all three were small (less than 7 millimetres, or about one-fifth of an inch) at the start of the study.
Real risk factors
The 46 growing aneurysms in the study were 12 times more likely to rupture than those that stayed the same size, according to the researchers. They calculated the risk of rupture for growing aneurysms at 2.4% per patient-year, compared with 0.2% for aneurysms that stayed the same size.
The researchers also found that smoking and the initial size of the aneurysm were independent predictors of aneurysm growth, according to the study appearing online July 2 in the journal Radiology.
"Given what a devastating event a ruptured brain aneurysm is, we are very motivated to identify the real risk factors for rupture," lead author Dr J Pablo Villablanca, chief of diagnostic neuroradiology at the David Geffen School of Medicine at the University of California, Los Angeles, said in a journal news release.
Villablanca said the study findings show the need to perform follow-up imaging of patients to monitor for possible growth in aneurysms, even small ones.
The U.S. National Institute of Neurological Disorders and Stroke has more about brain aneurysm.