Abstract: In some aspects, a resonator device includes a dielectric substrate, a ground plane on a first side of the substrate, and conductors on a second, opposite side of the substrate. The conductors include first and second resonators and two baluns. Each balun includes a feed, a first branch and a second branch. The feed is connected to the first and second branches, and the first and second branches are capacitively coupled to the respective first and second resonators. The first branch includes a delay line configured to produce a phase shift relative to the second branch. The resonator device includes a sample region configured to support a magnetic resonance sample between the first and second resonators.

Abstract: In some aspects, a resonator device includes a dielectric substrate, a ground plane on a first side of the substrate, and conductors on a second, opposite side of the substrate. The conductors include first and second resonators and two baluns. Each balun includes a feed, a first branch and a second branch. The feed is connected to the first and second branches, and the first and second branches are capacitively coupled to the respective first and second resonators. The first branch includes a delay line configured to produce a phase shift relative to the second branch. The resonator device includes a sample region configured to support a magnetic resonance sample between the first and second resonators.

Abstract: In some aspects, a resonator device for magnetic resonance applications is described. In some examples, the resonator device includes a resonator body that includes a periodic arrangement of cells about a central interior region. Each cell includes a dielectric substrate and a conductor disposed on the dielectric substrate. The periodic arrangement of the cells defines a periodic network of inductive and capacitive elements adapted to produce a magnetic field in the central interior region. The cells can be arranged according to various topologies that form various capacitive and inductive schemes. In some implementations, a dielectric substrate and thin superconductor are used, and the resonator device exhibits a high quality factor (Q) and low losses.

Abstract: In some aspects, polarization of a spin ensemble can be increased using cavity-based techniques. A resonator applies a drive field to a spin ensemble in a sample in a static magnetic field. The drive field couples the spin ensemble with a cavity, and the coupling increases the polarization of the spin ensemble. In some cases, the sample is thermally insulated from the cavity, for example, to maintain the sample at a higher temperature than the cavity. In some implementations, the spin ensemble achieves a polarization that is higher than its thermal equilibrium polarization.

Abstract: In some aspects, polarization of a spin ensemble can be increased using cavity-based techniques. A sample contains a first spin ensemble and a second spin ensemble. A drive field couples the first spin ensemble with a cavity, and the coupling increases the polarization of the first spin ensemble. Polarization is transferred from the first spin ensemble to the second spin ensemble. In some examples, the polarization is transferred from a solvent or an abundant species to a solute or a dilute species in the sample.

Abstract: In some aspects, polarization of a spin ensemble can be increased using cavity-based techniques. A magnetic resonance imaging (MRI) system includes a cavity and a resonator. The cavity is adapted to interact with a spin ensemble in an imaging subject in a static magnetic field. The resonator is adapted to generate an interaction between the cavity and the spin ensemble that increases polarization of the spin ensemble. In some implementations, the spin ensemble achieves a polarization that is higher than its thermal equilibrium polarization.

Abstract: In some aspects, a resonator device includes a dielectric substrate, a ground plane on a first side of the substrate, and conductors on a second, opposite side of the substrate. The conductors include first and second resonators and two baluns. Each balun includes a feed, a first branch and a second branch. The feed is connected to the first and second branches, and the first and second branches are capacitively coupled to the respective first and second resonators. The first branch includes a delay line configured to produce a phase shift relative to the second branch. The resonator device includes a sample region configured to support a magnetic resonance sample between the first and second resonators.

Abstract: In some aspects, a resonator device for magnetic resonance applications is described. In some examples, the resonator device includes a resonator body that includes a periodic arrangement of cells about a central interior region. Each cell includes a dielectric substrate and a conductor disposed on the dielectric substrate. The periodic arrangement of the cells defines a periodic network of inductive and capacitive elements adapted to produce a magnetic field in the central interior region. The cells can be arranged according to various topologies that form various capacitive and inductive schemes. In some implementations, a dielectric substrate and thin superconductor are used, and the resonator device exhibits a high quality factor (Q) and low losses.

Abstract: In some aspects, polarization of a spin ensemble can be increased using cavity-based techniques. A resonator applies a drive field to a spin ensemble in a sample in a static magnetic field. The drive field couples the spin ensemble with a cavity, and the coupling increases the polarization of the spin ensemble. In some cases, the sample is thermally insulated from the cavity, for example, to maintain the sample at a higher temperature than the cavity. In some implementations, the spin ensemble achieves a polarization that is higher than its thermal equilibrium polarization.

Abstract: In some aspects, polarization of a spin ensemble can be increased using cavity-based techniques. A sample contains a first spin ensemble and a second spin ensemble. A drive field couples the first spin ensemble with a cavity, and the coupling increases the polarization of the first spin ensemble. Polarization is transferred from the first spin ensemble to the second spin ensemble. In some examples, the polarization is transferred from a solvent or an abundant species to a solute or a dilute species in the sample.

Abstract: In some aspects, polarization of a spin ensemble can be increased using cavity-based techniques. A magnetic resonance imaging (MRI) system includes a cavity and a resonator. The cavity is adapted to interact with a spin ensemble in an imaging subject in a static magnetic field. The resonator is adapted to generate an interaction between the cavity and the spin ensemble that increases polarization of the spin ensemble. In some implementations, the spin ensemble achieves a polarization that is higher than its thermal equilibrium polarization.

Abstract: A magnet assembly primarily for use in MRI applications is disclosed. The magnet assembly is composed of a single disk and ring permanent magnet set connected to a C-type magnet yoke and return fixture with asymmetrically arranged poles. Together, the permanent magnets create a strong magnetic field that has a large static gradient in the central enclosure. The magnet assembly is primarily designed for diffusion based MRI scanning but can perform routine MRI scanning as well.

Abstract: Cylindrical bi-planar gradient coil assemblies for use in open magnetic resonance imaging, wherein each of the coil assemblies contains in sequential order (i) a circular primary coil set placed flat above a cylindrical planar substrate, (ii) cooling means, (iii) 0th and 2nd order shims, (iv) shield layers, and (v) 1st order shims. In use the gradient coil assemblies are disposed symmetrically to each other about a plane of symmetry parallel to each.

Abstract: Cylindrical bi-planar gradient coil assemblies for use in open magnetic resonance imaging, wherein each of the coil assemblies contains in sequential order (i) a circular primary coil set placed flat above a cylindrical planar substrate, (ii) cooling means, (iii) 0th and 2nd order shims, (iv) shield layers, and (v) 1st order shims. In use the gradient coil assemblies are disposed symmetrically to each other about a plane of symmetry parallel to each.

Abstract: A magnet primarily for use in MRI applications comprises a pair of poles oriented about a plane of symmetry parallel to each therebetween defining an air gap region, magnetic field sources secured on the surfaces of the poles opposite the air gap that have yokes disposed on them, the yokes connected to each other by returns so that the entire magnet assembly can form a closed magnetic flux circuit to substantially confine the magnetic fields generated by the apparatus in the air gap where an imaging region is formed to place subjects for the purposes of examination.

Abstract: A magnet assembly primarily for use in MRI applications is disclosed comprising two main permanent magnet rings that are spaced-apart and arranged to be coaxially aligned with two easy-access openings. The magnetization direction in each magnet ring is substantially radially oriented and maintains an anti-parallel orientation with respect to each other. Together, these two magnet rings create a homogeneous and strong magnetic field in the central enclosure between them with two orthogonal access paths to the enclosure. Through one access pathway a patient can be inserted while through the other pathway a doctor can fully access the patient and perform interventional procedures during a real-time MRI scan. Embodiments of the system also have poles and yokes that shape the field and minimize fringe fields. Embodiments of this magnet assembly can achieve high magnetic fields for whole-body scanning without saturating the magnet pole and other structures.

Abstract: A magnet assembly primarily for use in MRI Interventional applications having an array of four mam permanent magnets that are spaced-apart and arranged into a ring-like geometry with six easy-access openings The magnetization direction in each permanent magnet is anti-parallel to any other adjacent permanent magnet in the ?ng assembly while it is parallel to any other permanent magnet in the array that is oppositely located just as in a quadrupolar system Such an arrangement has the advantage of concentrating the magnetic field inside the nng enclosure while minimizing magnetic field generated outside Together, these four spatially spaced-apart permanent magnets create a very homogeneous and strong magnetic field in the central enclosure with two orthogonal access paths and one parallel access path to the enclosure Through one access pathway a patient can be inserted while through the other pathways a doctor can fully access the patient.

Abstract: A compact whole-body open circular magnet system for MRI purposes includes a protrusion overhanging the central homogeneous field region. The overhanging protrusion permits a reduction of the total magnet homogeneity requirements of the MRI system. Further reducing the radius of this protrusion increases access to a patient under examination but diminishes the homogeneity. Active shimming means incorporated in a gradient coil can regain the original homogeneity while maintaining increased patient access.

Abstract: A magnet assembly primarily for use in MRI Interventional applications having an array of four mam permanent magnets that are spaced-apart and arranged into a ring-like geometry with six easy-access openings The magnetization direction in each permanent magnet is anti-parallel to any other adjacent permanent magnet in the ?ng assembly while it is parallel to any other permanent magnet in the array that is oppositely located just as in a quadrupolar system Such an arrangement has the advantage of concentrating the magnetic field inside the nng enclosure while minimizing magnetic field generated outside Together, these four spatially spaced-apart permanent magnets create a very homogeneous and strong magnetic field in the central enclosure with two orthogonal access paths and one parallel access path to the enclosure Through one access pathway a patient can be inserted while through the other pathways a doctor can fully access the patient.

Abstract: A magnet primarily for use in MRI applications comprises a pair of poles oriented about a plane of symmetry parallel to each therebetween defining an air gap region, magnetic field sources secured on the surfaces of the poles opposite the air gap that have yokes disposed on them, the yokes connected to each other by returns so that the entire magnet assembly can form a closed magnetic flux circuit to substantially confine the magnetic fields generated by the apparatus in the air gap where an imaging region is formed to place subjects for the purposes of examination.