Applications of angiography have expanded to include not only diagnostic proce- dures but also therapeutic interventions. The introduction of regional administra- tion of vasoactive drugs through percutaneously placed angiographic catheters was soon followed by methods of transcatheter vessel occlusion using temporary or permanent embolic materials. At the same time methods of opening up nar- rowed or completely obstructed blood vessels with percutaneously introduced balloon catheters were being perfected. Thus, regional blood flow reduction or regional blood flow increase can now be...