A new mechanically rotated 20 MHz intravascular ultrasound guide wire (0.032 inch) with a transducer core was placed through the central lumen of a peripheral arterial balloon-expandable stent. Using an anesthetized canine model, 11 stents were then deployed into the iliac or femoral arteries. Eight stents were successfully deployed with proper position and full stent expansion documented by ultrasound imaging. Four of the stents were overlapping and the double row of stent struts at the region of overlap was easily seen. Three stents were unsuccessfully deployed because of undersizing, as clearly documented by ultrasound imaging showing stent strut recoil. As a result, the procedure was modified by performing ultrasound measurements of arterial dimensions before stent selection. There were no complications attributed to the ultrasound guide wire. This study demonstrates an effective combination of diagnostic and therapeutic devices that may allow more precise placement of intravascular stents.