Endovascular coiling is a procedure performed to block blood flow into an aneurysm (a weakened area in the wall of an artery). Endovascular coiling is a more recent treatment for brain aneurysms. Endovascular coiling is a minimally invasive technique, which means an incision in the skull is not required to treat the brain aneurysm. Rather, a catheter is used to reach the aneurysm in the brain