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A method for fast 3D tracking using tuned fiducial markers and a limited projection reconstruction FISP (LPR‐FISP) sequence
Author(s) -
Flask Chris,
Elgort Daniel,
Wong Eddy,
Shankaranarayanan Ajit,
Lewin Jonathan,
Wendt Michael,
Duerk Jeffrey L.
Publication year - 2001
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.1227
Subject(s) - fiducial marker , imaging phantom , projection (relational algebra) , orientation (vector space) , tracking (education) , scanner , computer vision , computer science , artificial intelligence , magnetic resonance imaging , sequence (biology) , physics , algorithm , optics , mathematics , medicine , radiology , geometry , psychology , pedagogy , genetics , biology
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. J. Magn. Reson. Imaging 2001;14:617–627. © 2001 Wiley‐Liss, Inc.