According to some aspects, a portable magnetic resonance imaging system is provided, comprising a Bo magnet configured to produce a Bo magnetic field for an imaging region of the magnetic resonance imaging system, a noise reduction system configured to detect and suppress at least some electromagnetic noise in an operating environment of the portable magnetic resonance imaging system, and electromagnetic shielding provided to attenuate at least some of the electromagnetic noise in the operating environment of the portable magnetic resonance imaging system, the electromagnetic shielding arranged to shield a fraction of the imaging region of the portable magnetic resonance imaging system. According to some aspects, the electromagnetic shield comprises at least one electromagnetic shield structure adjustably coupled to the housing to provide electromagnetic shielding for the imaging region in an amount that can be varied. According to some aspects, substantially no shielding of the imaging region is provided.

A magnetic shield apparatus for shielding magnetic field probes. The shield apparatus comprises an outer shield, and an inner shield contained within the outer shield. A magnetic field sensor is housed in the inner shield, and the outer shield and the inner shield comprise a magnetically permeable material, enclosing a volume and having at least a first end that is open.

A magnetocardiography (MCG) system includes a passively shielded enclosure having walls defining the passively shielded enclosure, each of the walls including passive magnetic shielding material to reduce an ambient background magnetic field within the passively shielded enclosure; an MCG measurement device including optically pumped magnetometers (OPMs); and active shield coils within the passively shielded enclosure and stationary relative to the passively shielded enclosure and the MCG measurement device, wherein the active shield coils are configured to further reduce the ambient background magnetic field within a user area of the passively shielded enclosure.

The present disclosure relates to a shimming device. The shimming device may include at least one supporting component each of which is configured with a plurality of wire groove groups. Each of the plurality of wire groove groups may include a plurality of wire grooves. Each of the plurality of wire grooves may be in a closed shape. The closed shapes formed by the plurality of wire grooves may be nested. The shimming device may further include wires arranged in the wire grooves of the plurality of wire groove groups of the at least one supporting component.

A magnetic resonance (MR) system is provided. The system includes a main magnet assembly configured to generate a polarizing magnetic field, a gradient coil assembly including a plurality of gradient coils configured to apply at least one gradient field to the polarizing magnetic field, and a shield assembly positioned between the main magnet assembly and the gradient coil assembly. The shield assembly includes a conductive layer fabricated with an electrically conductive material and defining grooves positioned through the conductive layer, wherein the grooves are configured to block motional eddy currents caused by actions of the polarizing magnetic field and the at least one gradient field when the at least one gradient field is applied.

The present disclosure provides transmit/receive (T/R) systems for NMR or MRI systems. In one configuration, the systems and methods provided herein may use passively-shielded coils that are compatible with low-field operational environment to replace conventional T/R systems and spatial gradient systems. In some configurations, a low-field imaging T/R system is provided that is designed for nuclear magnetic stimulation and local flux sensitivity, while automatically rejecting incident radiant electromagnetic noise. The design advantageously leverages low required frequencies to distribute the pulse synthesis task, yielding a smaller system with easier maintenance and lower cost. The system may include distributed coil nodes that include a primary radiofrequency (RF) coil configured to transmit and receive RF signals and a secondary coil configured to passively shield the primary RF coil.

A magnetic sensor includes a magnetic field conversion unit that outputs an output magnetic field, a magnetic field detection unit that the output magnetic field can be applied, and a magnetic shield that shields external magnetic fields. The length of the magnetic field conversion unit in the third direction is greater than the length in the second direction. The magnetic shield overlaps the magnetic field conversion unit and the magnetic field detection unit. The magnetic field detection unit includes a Wheatstone bridge circuit in which a first bridge circuit including first and second magnetic field detection units and a second bridge circuit including third and fourth magnetic field detection units are connected in parallel. The first through fourth magnetic field detection units include two magnetoresistive units, and two of the magnetoresistive units have magnetoresistive effect elements that include magnetization fixed layers whose magnetization directions differ from each other.

A magnetic sensor includes a magnetic field conversion unit that outputs an output magnetic field, a magnetic field detection unit that the output magnetic field can be applied, and a magnetic shield that shields external magnetic fields. The length of the magnetic field conversion unit in the third direction is greater than the length in the second direction. The magnetic shield overlaps the magnetic field conversion unit and the magnetic field detection unit. The magnetic field detection unit includes a Wheatstone bridge circuit in which a first bridge circuit including first and second magnetic field detection units and a second bridge circuit including third and fourth magnetic field detection units are connected in parallel. The first through fourth magnetic field detection units include two magnetoresistive units, and two of the magnetoresistive units have magnetoresistive effect elements that include magnetization fixed layers whose magnetization directions differ from each other.

A split cylindrical superconducting magnet system including two half magnets, each half magnet comprising superconducting magnet coils retained in an outer vacuum chamber, having a thermal radiation shield located between the magnet coils and the outer vacuum chamber, wherein the thermal radiation shield is shaped such that the axial spacing between thermal radiation shields of respective half magnets is greater at their internal diameter than at their outer diameter.

A magnetic resonance imaging device may include a field generator configured to provide a magnetic field in an imaging volume of the magnetic resonance imaging device. The field generator may include at least one magnet that confines the imaging volume in at least one spatial direction. The at least one magnet may be curved in such a way that a perpendicular distance between a line oriented along a direction of access to the imaging volume and a surface directed towards the imaging volume of the at least one magnet varies in the direction of access to the imaging volume.