Abstract: An MRI apparatus and method comprises an MRI system having a plurality of gradient coils positioned about a bore of a magnet, and an RF transceiver system and an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly to acquire MR images. The magnet comprises a main coil former and a shield coil former arranged radially around the bore of the magnet, wherein a radius of the shield coil former is greater than a radius of the main coil former. The magnet also includes at least one main coil affixed to the main coil former, at least one shield coil affixed to the shield coil former, and at least one structural member affixed to the main coil former and to the shield coil former to provide structural support and enable longitudinal alignment adjustment between the main coil former and the shield coil former.

Abstract: A superconducting magnet coil interface and method providing coil stability are provided. A superconducting coil arrangement includes a superconducting coil and a thermal interface coupled to the superconducting coil. The thermal interface is configured to intercept frictional heat before reaching the superconducting coil. The superconducting coil arrangement further includes a plurality of channels extending within at least a portion of the thermal interface and towards the superconducting coil. The plurality of channels are configured to receive therein a cooling liquid.

Abstract: A displacer for adjusting a level of a liquid cryogen in a cryostat. The displacer including an expandable member at least partially defining a sealed chamber. The expandable member being configured to transition from a collapsed state where the sealed chamber has a smaller volume to an expanded state where the sealed chamber has a larger volume. The displacer includes a first end piece attached to a first end of the expandable member and a second end piece attached to a second end of the expandable member.

Abstract: A coil assembly and a magnetic resonance imaging system employing same are disclosed. The coil assembly includes a main gradient coil assembly having a first section positioned at a first end of the MRI system distal to a patient support system and a second section positioned at a second end of the MRI system proximate to the patient support system. A first RF shield is disposed around at least a portion of the first section of the main gradient coil assembly. A second RF shield is disposed around at least a portion of the second section of the main gradient coil assembly. An aperture extends between the first section and the second section of the main gradient coil assembly and a conduit extends across the aperture. The conduit includes a first end coupled to the first RF shield and a second end coupled to the second RF shield. A hydraulic or electrical connection is disposed within and extends through the conduit. The conduit may also be an antenna element.

Abstract: An apparatus for magnetic resonance imaging is described having a casing with an inner bore which in some embodiments is substantially frustoconical shape for receiving a subject. The apparatus contains devices disposed in the casing to create a uniform field within an inner bore. The apparatus employs dual access since the inner bore has a first and second end at the outer edge of the casing for which the part of the subject's body would travel so as to be imaged. Further, in some embodiments, the apparatus provides one or more recesses for inserting at least one gradient coils into position about an inner bore. The MRI system induces resonance in selected dipoles in an examination region created along an inner bore of a casing housing in a magnetic resonance imaging system such that the selected dipoles generate magnetic resonance signals to create an image representation of the part of the subject's body.

Abstract: A system for cooling a gradient coil assembly of a magnetic resonance imaging (MRI) system includes a gradient coil having a first surface comprising a plurality of conductors and a plurality of inter-turn channels. Each inter-turn channel is located between turns of the plurality of conductors. The system also includes a seal layer applied to the first surface of the gradient coil to seal the inter-turn channels. The inter-turn channels are configured to transport a cooling fluid. Alternatively, at least one cooling tube may be located in the inter-turn channels of the gradient coil in order to transport a cooling fluid.

Abstract: A system for cooling a gradient coil assembly of a magnetic resonance imaging (MRI) system includes a gradient coil having a first surface comprising a plurality of conductors and a plurality of inter-turn channels. Each inter-turn channel is located between turns of the plurality of conductors. The system also includes a seal layer applied to the first surface of the gradient coil to seal the inter-turn channels. The inter-turn channels are configured to transport a cooling fluid. Alternatively, at least one cooling tube may be located in the inter-turn channels of the gradient coil in order to transport a cooling fluid.

Abstract: A Magnetic Resonance Imaging (MRI) system is disclosed. The MRI system includes a cryogenic magnet assembly with a cryogenic vessel housing a superconducting magnet. Disposed radially inboard of the cryogenic magnet assembly are a gradient coil module and a plurality of room temperature steel rings proximate to the gradient coil module. A field of view is defined by at least the superconducting magnet, the gradient coil module, and the plurality of room temperature steel rings. In response to the superconducting magnet being energized, the room temperature steel rings create high order harmonics that serve to expand the magnetic field homogeneity FOV, and low order harmonics that tend to degrade the magnetic field homogeneity within the FOV. The low order harmonics are compensated for by the cryogenic magnet assembly.

Abstract: A system for providing shielded dynamic shimming in a magnet assembly of a magnetic resonance imaging (MRI) scanner includes a main shim coil set located at a first radius in a gradient coil assembly of the magnet assembly. The system also includes a dynamic shim insert located at a second radius in the magnet assembly. The second radius is less than the first radius and is less than a radius of an RF coil in the magnet assembly. The main shim coil set may be operated as a shielding shim coil set for the dynamic shim insert.

Abstract: A MRI shim element includes a plurality of thin wires extending substantially parallel to each other wherein each wire has cross sectional dimensions less than ?sk, wherein ?sk is the wire's skin depth.

Abstract: A MRI shim element includes a plurality of thin wires extending substantially parallel to each other wherein each wire has cross sectional dimensions less than ?sk, wherein ?sk is the wire's skin depth.

Abstract: An apparatus for magnetic resonance imaging having a magnetic assembly with a main magnet, a shielding system positioned outside the main magnet, and a first and second space for positioning the imaged and non-imaged extremity. Various apparatus with distinct vessels and casings are described with a magnetic assembly and ferromagnetic shielding systems. In yet a further aspect, an apparatus for resonance imaging having additional shim elements for compensating effects from non-axisymmetrical shape of ferromagnetic shielding casing is disclosed. Additionally, an apparatus for magnetic resonance imaging is described having a dedicated space outside the imaging region and where the dedicated space has support element for resting non-image extremity as part of the structure of the imager.

Abstract: A Magnetic Resonance Imaging (MRI) system is disclosed. The MRI system includes a cryogenic magnet assembly with a cryogenic vessel housing a superconducting magnet. Disposed radially inboard of the cryogenic magnet assembly are a gradient coil module and a plurality of room temperature steel rings proximate to the gradient coil module. A field of view is defined by at least the superconducting magnet, the gradient coil module, and the plurality of room temperature steel rings. In response to the superconducting magnet being energized, the room temperature steel rings create high order harmonics that serve to expand the magnetic field homogeneity FOV, and low order harmonics that tend to degrade the magnetic field homogeneity within the FOV. The low order harmonics are compensated for by the cryogenic magnet assembly.

Abstract: A magnetic field generating apparatus for use in magnetic resonance imaging (MRI) is disclosed. The apparatus includes an annular magnet field generator defining a patient bore, a gradient coil disposed between the magnetic field generator and the patient bore, a first set of shim elements, and a second set of shim elements. The patient bore has an imaging volume, a z-axis, and an isocenter. The first set of shim elements are disposed at a region between the magnetic field generator and the imaging volume, and the second set of shim elements are disposed at the region at a location having equal to or greater than a specified Z/R ratio, where Z defines an axial distance from the isocenter and R defines a radial distance from the z-axis.

Abstract: An apparatus for magnetic resonance imaging having a magnetic assembly with a main magnet, a shielding system positioned outside the main magnet, and a first and second space for positioning the imaged and non-imaged extremity. Various apparatus with distinct vessels and casings are described with a magnetic assembly and ferromagnetic shielding systems. In yet a further aspect, an apparatus for resonance imaging having additional shim elements for compensating effects from non-axisymmetrical shape of ferromagnetic shielding casing is disclosed. Additionally, an apparatus for magnetic resonance imaging is described having a dedicated space outside the imaging region and where the dedicated space has support element for resting non-image extremity as part of the structure of the imager.

Abstract: An apparatus for magnetic resonance imaging is described having a casing with an inner bore which in some embodiments is substantially frustoconical shape for receiving a subject. The apparatus contains devices disposed in the casing to create a uniform field within an inner bore. The apparatus employs dual access since the inner bore has a first and second end at the outer edge of the casing for which the part of the subject's body would travel so as to be imaged. Further, in some embodiments, the apparatus provides one or more recesses for inserting at least one gradient coils into position about an inner bore. The MRI system induces resonance in selected dipoles in an examination region created along an inner bore of a casing housing in a magnetic resonance imaging system such that the selected dipoles generate magnetic resonance signals to create an image representation of the part of the subject's body.

Abstract: An MRI magnet assembly includes a pair of cryostat enclosures each housing a superconducting primary shield coil. The primary shield coil is dimensioned with an outer diameter greater than that of the main coil and is axially spaced away from the magnet pole significantly farther than is the main coil. This design provides for increased accessibility and visibility within the gap defined between the cryostat enclosures, and allows for reduced amounts of superconducting material in the coils. A set of field shaping coils is mounted radially inwardly and closely axially adjacent to the magnet pole and axially between the main coil and the shield coil.

Abstract: A cylindrical magnet assembly for use in magnetic resonance imaging apparatus has a radially compact construction which eliminates prior manufacturing steps. Recesses are formed in insulation layers for receiving complimentary shaped bus bars. Because the bus bars are dimensioned to fit flush within the recesses, they do not add to the radial growth of the magnet assembly.

Abstract: A cylindrical magnet assembly for use in magnetic resonance imaging apparatus has a radially compact construction which eliminates prior manufacturing steps. Recesses are formed in insulation layers for receiving complimentary shaped bus bars. Because the bus bars are dimensioned to fit flush within the recesses, they do not add to the radial growth of the magnet assembly.