Active MR visualization of a vascular guidewire in vivo

The purpose of this study was development of an actively visualized .035-inch vascular guidewire for use in MR-guided interventions. The guidewire was actively visualized by inclusion of a 6-cm-long radiofrequency coil in its tip. A high contrast outline of the distal tip of the guidewire was obtained by acquiring an image with the radiofrequency coil as the receiving antenna. The position of the guidewire relative to the surrounding anatomy was determined by overlaying the guidewire image on a previously acquired road map. The guidewire was evaluated in vivo in the abdominal vessels of a rabbit and swine at 1.5 T. The built-in radiofrequency coil delivered a high contrast signal over its full length, enabling visualization of the position and curvature of the tip of the guidewire. The ability to see the curvature of the guidewire over several centimeters significantly eased manipulation into targeted vessels and represents an important advance toward MR-guided vascular interventions.