The refinement in the intravascular techniques has revolved upon the development of new material and a better understanding of neurophysiology. Access has become less of a limitation, and more emphasis is now placed on getting the job done: closing a fistula, obliterating a malformation, or filling an aneurysm. Embolic materials available have greatly changed according to the indication at hand. The focus now is on the specific uses for the agent instead of toxicity or dose-response trials.