System for 3-D Real-Time Tracking of MRI-Compatible Devices by Image Processing

Real-time processing of MRIs is reported as a method of 3-D tracking of mechanical devices within the field of view using passive microcoil fiducials. The specific implementation described makes use of two scan planes for full 3-D tracking of a 5-DOF manipulator arm used for prostate biopsy under image guidance. Real-time tracking was observed with a maximum update rate of 0.42 frames per second for a maximum probe velocity of 10 mm/s. The localization of fiducials had a mean error of 0.36 ($\pm$ 0.17) mm ( $p ≪ 0.02$ ), leading to a mean error in the needle tip position of 2.6 ($\pm$0.3) mm ( $p ≪ 0.05$).