Abstract: Various embodiments are described herein for an apparatus and a method for measuring and characterizing geometric distortions for a region of interest in images obtained using magnetic resonance. The method comprises deriving a computed set of 3D distortion vectors for a set of points within a region of interest covered by a phantom by using harmonic analysis to solve an associated boundary value problem based on boundary conditions derived from a measured set of 3D distortion vectors. The characterized image distortions may be used for various purposes such as for image correction or for shimming, for example.

Abstract: Various embodiments are described herein for an apparatus and a method for measuring and characterizing geometric distortions for a region of interest in images obtained using magnetic resonance. The method comprises deriving a computed set of 3D distortion vectors for a set of points within a region of interest covered by a phantom by using harmonic analysis to solve an associated boundary value problem based on boundary conditions derived from a measured set of 3D distortion vectors. The characterized image distortions may be used for various purposes such as for image correction or for shimming, for example.

Abstract: Various embodiments are described herein for an apparatus and a method for measuring and characterizing geometric distortions for a region of interest in images obtained using magnetic resonance. The method comprises deriving a computed set of 3D distortion vectors for a set of points within a region of interest covered by a phantom by using harmonic analysis to solve an associated boundary value problem based on boundary conditions derived from a measured set of 3D distortion vectors. The characterized image distortions may be used for various purposes such as for image correction or for shimming, for example.

Abstract: Disclosed herein is a magnet assembly that includes at least two magnets arranged in a fixed spaced relationship with one another thereby to define a space between the magnets that encompasses an imaging volume. Each of the magnets produces a variety of magnetic field strengths across inward-facing surfaces thereof that, in combination, produce an acceptably homogeneous magnetic field in the imaging volume. Also disclosed is a method of defining a magnetic field for an imaging volume. The method comprises generating an initial model of a magnet assembly; estimating a magnetic field for the imaging volume based on the model; calculating deviation between the estimated magnetic field and a target magnetic field for the imaging volume; and updating the model to reduce the deviation by modifying the magnet assembly to produce a variety of magnetic field strengths that, in combination, produce substantially the target magnetic field in the imaging volume.

Abstract: Various embodiments are described herein for an apparatus and a method for measuring and characterizing geometric distortions for a region of interest in images obtained using magnetic resonance. The method comprises deriving a computed set of 3D distortion vectors for a set of points within a region of interest covered by a phantom by using harmonic analysis to solve an associated boundary value problem based on boundary conditions derived from a measured set of 3D distortion vectors. The characterized image distortions may be used for various purposes such as for image correction or for shimming, for example.

Abstract: Disclosed herein is a magnet assembly that includes at least two magnets arranged in a fixed spaced relationship with one another thereby to define a space between the magnets that encompasses an imaging volume. Each of the magnets produces a variety of magnetic field strengths across inward-facing surfaces thereof that, in combination, produce an acceptably homogeneous magnetic field in the imaging volume. Also disclosed is a method of defining a magnetic field for an imaging volume. The method comprises generating an initial model of a magnet assembly; estimating a magnetic field for the imaging volume based on the model; calculating deviation between the estimated magnetic field and a target magnetic field for the imaging volume; and updating the model to reduce the deviation by modifying the magnet assembly to produce a variety of magnetic field strengths that, in combination, produce substantially the target magnetic field in the imaging volume.

Abstract: Disclosed herein is a magnet assembly that includes at least two magnets arranged in a fixed spaced relationship with one another thereby to define a space between the magnets that encompasses an imaging volume. Each of the magnets produces a variety of magnetic field strengths across inward-facing surfaces thereof that, in combination, produce an acceptably homogeneous magnetic field in the imaging volume. Also disclosed is a method of defining a magnetic field for an imaging volume. The method comprises generating an initial model of a magnet assembly; estimating a magnetic field for the imaging volume based on the model; calculating deviation between the estimated magnetic field and a target magnetic field for the imaging volume; and updating the model to reduce the deviation by modifying the magnet assembly to produce a variety of magnetic field strengths that, in combination, produce substantially the target magnetic field in the imaging volume.