A technique performed by a neuroradiologist or a neurosurgeon in the treatment of brain aneurysms or brain AVMs. As an extension of an angiogram, a catheter is passed up into the arteries inside the brain into the arteries supplying blood flow to the AVM or inside an aneurysm. The blood vessel or aneurysm is then blocked off from the inside with either glue, metal coils or other substances. This is often performed as a prelude to surgery in brain AVMs, but occasionally may be curative without additional therapy.