Better Screening for Brain Aneurysms

New research by an international consortium, including a researcher from Lawrence Livermore National Laboratory in California, may help physicians better understand the chronological development of a brain aneurysm. The study was published in the June 2014 print issue of the journal Stroke.

A release from the laboratory written by Anne M Stark explains that a cerebral aneurysm (CA) “is a blood-filled bulge formed in response to a weakness in the wall at branching brain arteries. If the bulge bursts, the person can undergo a brain hemorrhage, which is a subtype of stroke and a life-threatening condition”.

The researchers, led by neurosurgeon Nima Etminan, used radiocarbon dating to date samples of ruptured and unruptured cerebral aneurysm tissue. The team found that the main structural constituent and protein — collagen type I — in cerebral aneurysms is distinctly younger than once thought. This discovery helps identify patients more likely to suffer from an aneurysm and embark on a path toward prevention.

The release explains that for decades, doctors have assumed that CAs rarely undergo structural change, and earlier theories speculated that CAs grow at a constant rate. The new findings challenge the concept that CAs are present for decades and that they undergo only sporadic episodes of structural change. In view of these findings, it seems more likely that they alternate between periods of stability and instability during which they are prone to rupture.

For patients with CAs who are more likely to undergo an aneurysm rupture due to risk factors such as smoking or hypertension, the international team including found that the age of collagen type I was significantly younger than those samples taken from people with no risk factors.

The ample amount of relatively young collagen type I in CAs suggests that collagen is changing all the time in aneurysms, which is significantly more rapid in patients with risk factors, according to researcher Bruce Buchholz.

Radiocarbon bomb-pulse dating uses an isotopic signature created by above-ground nuclear testing between 1955 and 1963, which nearly doubled the amount of carbon-14 in the atmosphere.

When the above-ground test-ban treaty took effect in 1963, atmospheric levels of radiocarbon began to decline as carbon-14 migrated into the oceans and biosphere. Living organisms naturally incorporate carbon into their tissues as the element moves through the food chain. As a result, the concentration of carbon-14 leaves a permanent time stamp on every biological molecule.

“This research may help doctors to formulate better screening and identification of those people at increased risk of an aneurysm rupture,” Buchholz said.