[video src="http://d2fexuft304e76.cloudfront.net/Pterional-HD" format="m4v,flv" poster="/images/noc-poster.jpg" options="autoplay" id="Pterional-HD"] The patient is a 44 year-old man who presented to the ED after the sudden onset of severe headache and was found to have an SAH on head CT....

A Cerebral Arteriovenous Malformation (AVM) is a rare tangle of blood vessels in the brain that carries a high risk of hemorrhaging.  Brain surgeons have found that "gluing" or blocking off the blood supply to these malformations before surgery cuts down on blood loss and patients do better....

At the Gamma Knife Center they like to be thorough. Before they perform radiosurgery on someone's brain they do exhaustive tests to locate the problem. One of the problems they treat is called Cerebral Arteriovenous Malformation, AVM for short. An AVM happens when small blood vessels in the brain form a tangled mass. This mass can cause brain cells to die, it can start bleeding, and it often causes headaches and sometimes seizures.