Abstract: A method of manufacturing an electromagnet coil for use in a magnetic resonance imaging (MRI) system includes: generating a coil surface representation defining a surface to contain the electromagnet coil; defining a set of performance metric functions, the set including a mutual inductance function defining mutual inductance between the electromagnet coil and a second electromagnet coil; defining a performance functional based on the coil surface representation and the set of performance metric functions; optimizing the performance functional; generating a current density pattern over the coil surface representation based on the optimized performance functional; and obtaining coil windings defining the electromagnet coil from the current density pattern.

Abstract: Some implementations provide an MRI system that includes: a housing having a bore accommodating a portion of a subject; a main magnet enclosed by said housing and configured to generate a substantially uniform magnet field within the bore; a gradient sub-system to provide perturbations to the substantially uniform magnet field; a flexible coil assembly configured to (i) receive radio frequency (RF) signals from the subject in response to the portion of the subject being scanned, and (ii) generate and apply B0 shimming to improve a field homogeneity of the substantially uniform magnetic field; and a control unit configured to: drive the gradient sub-system using a gradient waveform; and receive measurement results responsive to the gradient waveform such that a coupling between the gradient sub-system and the flexible coil assembly is determined and subsequently reduced in response to the determined coupling exceeding a pre-determined threshold.

Abstract: Described here are systems and methods for mitigating or otherwise removing the effects of short-term magnetic field instabilities caused by oscillations of the cold head in a cryogen-free magnet system used for magnetic resonance systems, such as magnetic resonance imaging (“MRI”) systems, nuclear magnetic resonance (“NMR”) systems, or the like.

Abstract: Some implementations provide a system that includes: a main magnet including a bore and configured to generate a substantially uniform magnetic field in the bore; one or more gradient coils configured to perturb the substantially uniform magnetic field in the bore, wherein perturbing the substantially uniform magnetic field results in a first varying magnetic field outside of the bore; and one or more shielding units located outside of the bore and configured to generate a second varying magnetic field configured to attenuate the first varying magnetic field outside of the bore.

Abstract: Described here are systems and methods for mitigating or otherwise removing the effects of short-term magnetic field instabilities caused by oscillations of the cold head in a cryogen-free magnet system used for magnetic resonance systems, such as magnetic resonance imaging (“MRI”) systems, nuclear magnetic resonance (“NMR”) systems, or the like.

Abstract: A method of manufacturing electromagnet coils for use in a magnetic resonance imaging (MRI) system is provided. The method comprises forming a coil representation of a coil surface for the electromagnet coils; setting a plurality of performance metric requirements for a plurality of performance metrics for the electromagnet coils, the plurality of performance metrics including a magnetic field-shape metric and an eddy-field metric; forming a performance functional, based on the coil representation and the plurality of performance metrics, for generating a current density pattern over the coil surface; optimizing the performance functional based on the plurality of performance metric requirements; generating a current density pattern over the coil surface based on the minimized performance functional; and obtaining coil windings from the current density pattern.

Abstract: Some implementations provide a system that includes: a main magnet including a bore and configured to generate a substantially uniform magnetic field in the bore; one or more gradient coils configured to perturb the substantially uniform magnetic field in the bore, wherein perturbing the substantially uniform magnetic field results in a first varying magnetic field outside of the bore; and one or more shielding units located outside of the bore and configured to generate a second varying magnetic field configured to attenuate the first varying magnetic field outside of the bore.

Abstract: Some implementations provide a system that includes: a main magnet including a bore and configured to generate a substantially uniform magnetic field in the bore; one or more gradient coils configured to perturb the substantially uniform magnetic field in the bore, wherein perturbing the substantially uniform magnetic field results in a first varying magnetic field outside of the bore; and one or more shielding units located outside of the bore and configured to generate a second varying magnetic field configured to attenuate the first varying magnetic field outside of the bore.

Abstract: A magnetic resonance (MR) imaging system includes: a main magnet configured to generate a volume of magnet field suitable for forming MR imaging; a transmit radio frequency (RF) coil assembly configured to transmit at least one RF signal; a receive radio frequency (RF) coil assembly configured to, in response to the at least one RF pulse, receive MR signals; a gradient coil assembly comprising (i) windings of coils arranged in a radial layer, and (ii) a first set of connectors embedded in the radial layer to reduce a radial extent occupied by the gradient coil assembly, the first set of electrical connectors configured to drive the windings of coils; and a control unit coupled to the transmit RF coil assembly, the receive RF coil assembly, and the gradient coils, the control unit configured to synchronously operate the gradient coil assembly, the transmit coil assembly, and the receive coil assembly.

Abstract: A method of manufacturing electromagnet coils for use in a magnetic resonance imaging (MRI) system is provided. The electromagnet coils are located in a non-homogeneous external magnetic field. The method comprises forming a coil representation of a coil surface for the electromagnet coils; setting limits for performance metrics for the electromagnet coils including a magnetic field-shape metric and at least one of an external torque metric and an external force metric, the external torque metric and the external force metric based, respectively, at least in part on a torque and a force exerted on the electromagnet coil by the non-homogeneous external magnetic field; forming a performance functional, based on the coil representation and the performance metrics, for generating a current density pattern over the coil surface; optimizing the performance functional and generating a current density pattern based on the optimized performance functional; and obtaining coil windings.

Abstract: A magnetic resonance imaging (MRI) system is provided. The system includes a main field magnet generating a main magnetic field B0. Moreover, the system further includes an integrated magnet device. The integrated magnet device has field-shift shield coils and gradient coils. The MRI system further includes a removable insert comprising field-shift shield coils. At least one substrate layer is included in the integrated magnet device to provide mechanical support for the field-shift coils and the gradient coils. Moreover, a cooling mechanism is provided to cool at least some of the magnets.

Abstract: Some implementations provide a MRI system configured to: access data encoding an input gradient waveform that would otherwise be used on a gradient sub-system of the MRI system to generate a gradient that corresponds to perturbations to the substantially uniform magnetic field; access data encoding a forward impulse response function and an inverse impulse response function, both characterizing a gradient generated from a target impulse input; pre-emphasizing the input gradient waveform by using both the forward impulse response function and the reverse impulse response function; and drive the gradient sub-system using the pre-emphasized gradient waveform such that distortions to the gradient caused by eddy currents within the gradient sub-system are substantially removed while radio-frequency (RF) samples for reconstructing an MRI image are being acquired from a grid that is substantially identical to when gradient sub-system is driven using the input gradient waveform.

Abstract: Described here are systems and methods for mitigating or otherwise removing the effects of short-term magnetic field instabilities caused by oscillations of the cold head in a cryogen-free magnet system used for magnetic resonance systems, such as magnetic resonance imaging (“MRI”) systems, nuclear magnetic resonance (“NMR”) systems, or the like.

Abstract: Some implementations provide a MRI system configured to: access data encoding an input gradient waveform that would otherwise be used on a gradient sub-system of the MRI system to generate a gradient that corresponds to perturbations to the substantially uniform magnetic field; access data encoding a forward impulse response function and an inverse impulse response function, both characterizing a gradient generated from a target impulse input; pre-emphasizing the input gradient waveform by using both the forward impulse response function and the reverse impulse response function; and drive the gradient sub-system using the pre-emphasized gradient waveform such that distortions to the gradient caused by eddy currents within the gradient sub-system are substantially removed while radio-frequency (RF) samples for reconstructing an MRI image are being acquired from a grid that is substantially identical to when gradient sub-system is driven using the input gradient waveform.

Abstract: A magnetic resonance imaging (MRI) system is provided. The system includes a main field magnet generating a main magnetic field B0. Moreover, the system further includes an integrated magnet device. The integrated magnet device has field-shift coils including primary field-shift coils and field-shift shield coils, the primary field shift coils being placed closer to an object to be imaged within the imaging volume than the field-shift shield coils. The gradient coils are placed between the primary field-shift coils and field-shift shield coils. At least one substrate layer is included to provide mechanical support for the field-shift coils and the gradient coils.

Abstract: Some implementations provide an MRI system that includes: a housing having a bore accommodating a portion of a subject; a main magnet enclosed by said housing and configured to generate a substantially uniform magnet field within the bore; a gradient sub-system to provide perturbations to the substantially uniform magnet field; a flexible coil assembly configured to (i) receive radio frequency (RF) signals from the subject in response to the portion of the subject being scanned, and (ii) generate and apply B0 shimming to improve a field homogeneity of the substantially uniform magnetic field; and a control unit configured to: drive the gradient sub-system using a gradient waveform; and receive measurement results responsive to the gradient waveform such that a coupling between the gradient sub-system and the flexible coil assembly is determined and subsequently reduced in response to the determined coupling exceeding a pre-determined threshold.

Abstract: In some implementations, a system includes: a housing having a bore in which a subject to be imaged is placed; a main magnet accommodated by the housing and configured to generate a substantially uniform magnetic field within the bore; an N electromagnet comprising a conductive member that includes a first set of one or more non-conductive paths that define at least one conductive channel and a second set of one or more non-conductive paths that, when an electric current is applied to the electromagnet, constrain the electric current along a defined portion of the at least one conductive channel; and a power amplifier configured to apply an electric current to the electromagnet.

Abstract: A method of manufacturing electromagnet coils for use in a magnetic resonance imaging (MRI) system is provided. The electromagnet coils are located in a non-homogeneous external magnetic field. The method comprises forming a coil representation of a coil surface for the electromagnet coils; setting limits for performance metrics for the electromagnet coils including a magnetic field-shape metric and at least one of an external torque metric and an external force metric, the external torque metric and the external force metric based, respectively, at least in part on a torque and a force exerted on the electromagnet coil by the non-homogeneous external magnetic field; forming a performance functional, based on the coil representation and the performance metrics, for generating a current density pattern over the coil surface; optimizing the performance functional and generating a current density pattern based on the optimized performance functional; and obtaining coil windings.

Abstract: Gradient coils are operated to acquire magnetic resonance (MR) signals encoding a first MRI image over a first region inside a main magnet of the MRI system in which at least a portion of a subject is placed, the first region being located within a volume of uniform magnetic field with inhomogeneity below a defined threshold. An active coil is energized to shift the volume of uniform magnetic field such that a second region inside the main magnet of the MRI system is located within the shifted volume of uniform magnetic field, at least a portion of the second region being located outside of the volume of uniform magnetic field before the volume of uniform magnetic field has been shifted. The gradient coil is operated to acquire MR signals encoding a second MRI image over the second region.

Abstract: Some implementations provide a system that includes: a main magnet including a bore and configured to generate a substantially uniform magnetic field in the bore; one or more gradient coils configured to perturb the substantially uniform magnetic field in the bore, wherein perturbing the substantially uniform magnetic field results in a first varying magnetic field outside of the bore; and one or more shielding units located outside of the bore and configured to generate a second varying magnetic field con figured to attenuate the first varying magnetic field outside of the bore.