Tracking planar orientations of active MRI needles

Purpose: To determine and track the planar orientation of active interventional devices without using localizing RF microcoils. Materials and Methods: An image-based tracking method that determines a device's orientation using projection images was developed. An automated and a manual detection scheme were implemented. The method was demonstrated in an in vivo mesocaval puncture procedure in swine, which required accurate orientation of an active transvascular needle catheter. Results: The plane of the catheter was determined using two projection images. The scan plane was adjusted automatically to follow the catheter plane, and its orientation with respect to a previously acquired target plane was displayed. The algorithm facilitated navigation for a fast and accurate puncture. Conclusion: Using image-based techniques, with no mechanical design changes, the orientation of an active intravascular probe could be tracked.