Automatic device tracking in a closed-bore MRI: principle and initial experimental results on a robotically driven needle

Introduction/Purpose An image-based localization of interventional tools or devices inside the magnet requires adequate, MR-visible markers and a powerful image processing tool to automatically detect them. In contrast to active tracking techniques, a substantial amount of time is needed for the acquisition of the marker images alone. In this work, a marker sequence at low spatial resolution was used to reduce the acquisition and hence the localization time. Inductively coupled radiofrequency (ICRF) miniature coils were used as markers to achieve efficient background suppression at very low flip angles. The parameters of an existing morphologic image processing tool [1] were adapted to allow 3D marker localization on poorly resolved MR images. The goal was to evaluate the performance of such an approach in a needle tracking experiment involving a robotic manipulator inside the magnet and to demonstrate the capabilities for potential applications in device tracking.