Patent ID: 9037213
Filing Date: 2015-05-19
Classification: G01R

Abstract:
1. A method of determining an instantaneous location and orientation of an object moving through a three-dimensional space within an imaging space of a magnetic resonance imaging apparatus comprising three gradient coils during operation of said magnetic resonance imaging apparatus, the method comprising: producing gradient field maps for said gradient coils prior to a scanning operation of the magnetic resonance imaging apparatus, wherein said gradient field maps are produced using tracking gradient command parameters; applying to said object a sensor for measurement of instantaneous values of magnetic fields which are generated by activation of said gradient coils within an imaging space of said magnetic resonance imaging apparatus; activating gradient coils of said magnetic resonance imaging apparatus during said scanning operation of said magnetic resonance imaging apparatus in imaging mode gradient activation so as to produce a magnetic field used for imaging; activating said gradient coils of said magnetic resonance imaging apparatus during said scanning operation of said magnetic resonance imaging apparatus using said tracking gradient command parameters in tracking mode gradient activation so as to produce a magnetic field used for tracking, wherein said magnetic field used for tracking is produced using only said three gradient coils without the need for RF activation; measuring instantaneous values of magnetic fields which are generated in said sensor by the tracking mode activation of said gradient coils of said magnetic resonance imaging apparatus; calculating predicted values of magnetic fields to be generated in said sensor by the tracking mode activation of said gradient coils by using said gradient field maps; and processing said measured instantaneous values of the magnetic fields generated by the tracking mode activation of said gradient coils, together with said calculated predicted values of magnetic fields to compute the instantaneous location and orientation of said object within said imaging space.