An aneurysm is a balloon-like enlargement of the wall of an artery in the brain. Aneurysms usually occur at the junction of the blood vessels of the brain. They may remain small and not cause problems or may enlarge with time and put pressure on the adjacent brain structures. Most importantly, aneurysms can rupture on an unpredictable basis, causing a brain hemorrhage. The hemorrhage may be small and cause a headache or may be large and cause various types of neurological problems, including coma and death. The featured image is a 3-dimensional angiogram revealing the arteries of the brain and an aneurysm represented by “An.”

If a patient survives the initial aneurysmal hemorrhage (known as subarachnoid hemorrhage), the aneurysm must be obliterated before it ruptures again. This is achieved either by surgery (microsurgical clipping) or coiling (endovascular coil embolization). In surgery, a craniotomy is performed to expose the aneurysm. A titanium alloy clip is then permanently applied to the neck of the aneurysm to prevent flow of blood into its dome. Once the clip is properly placed, the aneurysm no longer poses a risk of hemorrhage.

A metallic clip has been applied to the neck of the aneurysm.

Angiogram after surgery reveals the clip (yellow). The aneurysm has been obliterated by the clip and no longer shows up on the angiogram.