A cerebral aneurysm is a blood-filled bulge that forms due to a weakness in the wall of arteries in the brain. If it bursts, it can cause a brain hemorrhage and because of the high rate of death in these cases, researchers want to understand how aneurysms form and evolve.

"The advantage is seeing how dynamic they are and then basically changing your practices for managing them to be a bit more aggressive than what has been done previously."

Physicist Bruce Buchholz of the Lawrence Livermore National Laboratory was part of an international team that used radiocarbon dating of samples of ruptured and unruptured tissues. They found that a protein called collagen type 1 is distinctly younger than previously thought.

"People believe that they grew very slowly over time and then would break or that they would go through periodic cycles of being stable and grow. What we found is they appeared to be the same age regardless of how big they were, how old the person was, regardless if they were ruptured or not..."

And this can help with intervention.