Using simple surgical techniques, experimental carotid aneurysms are created which simulate some types of human berry aneurysms, both in hemodynamic and radiographic behavior. End to side anastomoses of an external jugular vein graft to the common carotid artery can be carried out by radiologic personnel with no formal surgical training. Factors which cause the aneurysms to fail and fill with clot are infection, incorporation of venous valves into the aneurysm sac, poor suturing technique, and perhaps a sac too large in comparison with its neck. The models are studied and followed by percutaneous catheter angiography, and show the swirling flow seen in clinical practice. These models may be used to study and refine percutaneous catheter occlusive techniques.