title: A method for fast 3D tracking using tuned fiducial markers and a limited projection reconstruction FISP (LPR-FISP) sequence.
abstract: This work demonstrates the feasibility of using wireless, tuned fiducial markers with a limited projection reconstruction-fast imaging with steady-state free precession sequence (LPR-FISP) to accurately obtain tracking information necessary for interactive scan plane selection in magnetic resonance imaging (MRI). The position and orientation of a rigid interventional device can be uniquely determined from the 3D coordinates of three fiducial markers mounted in a known configuration on the device. Three fiducial markers were tuned to the proton resonant frequency in a 0.2T open MR scanner and mounted to the surface of a cylindrical water phantom. An LPR-FISP sequence was developed to suppress the water phantom signal while preserving that of the fiducial markers through a nonselective low-tip-angle excitation and a dephaser gradient applied prior to data acquisition. A localization algorithm was developed to accurately calculate the 3D coordinates of the fiducial markers using four LPR-FISP projections in two orthogonal scan planes. The sequence repetition time (TR = 21 msec) and the limited projection set resulted in fast LPR-FISP coordinate acquisition times of approximately 170 msec with an accuracy (max error) of 3 mm on a 0.2T MR system. This fast, accurate tracking method provides the fundamental technology for interactive MRI scan plane definition for rigid interventional devices without the need for stereotactic cameras or reference frames.
authors.affiliation: Case Western Reserve University, University Hospital of Cleveland, Department of Radiology, Cleveland, Ohio 44106, USA.
authors.forename: C
authors.initials: C
authors.lastname: Flask
authors.forename: D
authors.initials: D
authors.lastname: Elgort
authors.forename: E
authors.initials: E
authors.lastname: Wong
authors.forename: A
authors.initials: A
authors.lastname: Shankaranarayanan
authors.forename: J
authors.initials: J
authors.lastname: Lewin
authors.forename: M
authors.initials: M
authors.lastname: Wendt
authors.forename: J L
authors.initials: JL
authors.lastname: Duerk
mesh_terms: D000465:Algorithms; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging