A cerebral aneurysm is an outpouching of a blood vessel in the brain which occurs due to weakness of the blood vessel wall. There are a number of factors that contribute to aneurysm formation including high blood pressure, smoking, genetics (family history), and connective tissue disorders. Sometimes no cause for aneurysm formation is identified. Aneurysms are dangerous because they can rupture, which results in bleeding around the brain, a condition called subarachnoid hemorrhage. Subarachnoid hemorrhage may result in stroke, coma, paralysis and possibly death. Many times aneurysms are found before they rupture because they are seen incidentally on imaging studies such as CTs or MRIs or because the aneurysm is causing symptoms. Aneurysms can be treated endovascularly, meaning minimally invasively through the wrist or the leg, with the use of devices such as coils, stents and intrasaccular flow disruptors. Aneurysms may also be treated with surgical clipping, in which the skull is opened, the aneurysm is dissected away from the brain and a clip is placed across the aneurysm.