System and method for operation and control of electromagnets
AssigneeSynaptive Medical Inc.
InventorsChad Tyler Harris, Andrew Thomas Curtis
Life of this patent
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Abstract
A system and method for compensation of radiofrequency (RF) spatial encoding misalignment errors due to gradient non-linearity in magnetic resonance imaging is described. The true magnetic field produced by the gradient coils in space are taken into account in order to encode the appropriate frequency band and offset of the RF pulse corresponding to the desired spatial encoding position and thickness. This method is applicable to any positionally (frequency) encoded radiofrequency (RF) pulses including slice or slab excitation pulses, inversion pulses, spin echo (refocusing) pulses and spatial saturation pulses.
Claims20
A computer-implemented method, using a computer processor in an operator workstation, for identification of frequency ranges for localization in a magnetic resonance imaging (MRI) device comprising the steps of:
- determine the frequency bandwidth and frequency offset, by the computer processor of the operator workstation, from a realistic spatially varying magnetic field over a slab in the x, y, and z axis;
- and
- use the frequency bandwidth and frequency offset to improve spatial localization accuracy of MRI in the presence of non-linear gradient fields;
- storing the improved spatial localization data in a database;
- and
- displaying the improved spatial localization data to an operator on an operator interface;
- wherein the slab is a 3D rectangular prism oriented arbitrarily in space, with its three orthogonal axes labelled in the x, y and z axis;
- wherein the z axis is commonly referred to as the slab select axis;
- wherein the improved spatial localization is applied to slab excitation, inversion, refocusing, saturation, or other radiofrequency pulse applications.
A system for identification of frequency ranges for localization in a magnetic resonance imaging (MRI) comprising:
- a computer processor;
- a set of magnet coils for generating a magnetic field, wherein the set of magnet coils are composed of a superconducting material;
- a set of gradient coils for generating linearly varying magnetic fields for imaging;
- and
- a transmit RF coil for excitation of the nuclei;
- wherein the processor of the MRI is configured to:
- determine the frequency bandwidth and frequency offset by the computer processor from a realistic spatially varying magnetic field over a slab in the x, y, and z axis;
- use the frequency bandwidth and frequency offset to improve spatial localization accuracy of MRI in the presence of non-linear gradient fields;
- store the improved spatial localization data in a database;
- and
- display the improved spatial localization data to an operator on an operator interface;
- wherein the slab is a 3D rectangular prism oriented arbitrarily in space, with its three orthogonal axes labelled in the x, y and z axis,
- wherein the z axis is commonly referred to as the slab select axis;
- wherein the improved spatial localization is applied to slab excitation, inversion, refocusing, saturation, or other radiofrequency pulse applications.
Dependencies are inferred from the claim text.