title: High-precision absolute positioning of medical instruments in MRI systems.
abstract: An absolute positioning technique has been developed for ferromagnetic markers in medical instruments and untethered devices operating in a magnetic resonance imaging (MRI) system. This technique allows high precision 3D readings of the location of the device with respect to the absolute center of the MRI bore. The local magnetic field induced by the device is used as a signature for localization from 3 one-dimensional projections. A convolution between two acquisitions based on opposite read-out gradients is used to obtain the absolute position of the device without any effect from the susceptibility distortion. The validity of the method has been demonstrated and its precision was found sufficient to correctly register the device position with MRI images.
authors.affiliation: NanoRobotics Laboratory, Department of Computer Engineering, Ecole Polytechnique de Montreal, Campus of the Université de Montréal, Québec, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: Aboussouan
authors.forename: Sylvain
authors.initials: S
authors.lastname: Martel
mesh_terms: D000465:Algorithms; D001185:Artificial Intelligence; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013525:Surgical Instruments