Abstract: Described herein are compact breast MRI systems having (i) an open, field-cycling magnet configured to produce and cycle between a first and second non-uniform B0 different from the first non-uniform B0, and (ii) a second component configured to produce a nonlinear spatial encoding gradient. Importantly, the open, field-cycling magnet and the spatial encoding gradients are customized to a specific imaging application. In particular, the second component contains one or several nonlinear DC gradient coils for spatial encoding. It also contains one or several a radiofrequency coils geometrically configured to have a non-planar configuration. Lastly, both the RF coils and DC encoding gradients are tailored specifically to the first non-uniform B0 magnetic field, the second non-uniform B0 magnetic field, or both. Artificial intelligence models trained to read imaging data can be incorporated as a component of the MRI systems. Also described are methods of using the disclosed breast MRI systems.

Abstract: Described herein are compact MRI systems having (i) an open, field-cycling magnet configured to produce and cycle between a first and second non-uniform B0 different from the first non-uniform B0, and (ii) a second component configured to produce a nonlinear spatial encoding gradient. Importantly, the open, field-cycling magnet and the spatial encoding gradients are customized to a specific imaging application. In particular, the second component contains one or several nonlinear DC gradient coils for spatial encoding. It also contains one or several a radiofrequency coils geometrically configured to have a non-planar configuration. Lastly, both the RF coils and DC encoding gradients are tailored specifically to the first non-uniform B0 magnetic field, the second non-uniform B0 magnetic field, or both. Artificial intelligence models trained to read imaging data can be incorporated as a component of the MRI systems. Also described are methods of using the disclosed MRI systems.

Abstract: A system includes a magnetic resonance gradient accessory within an MRI system. The MRI system includes a magnet housing, a superconducting magnet generating a magnet field B0 to which a patient is subjected, shim coils, RF coils, receiver coils, magnetic gradient coils, and a patient table. The magnetic resonance gradient accessory creates local magnetic gradient fields critical to image generation and provides for diffusion encoding of a specific body region.

Abstract: A magnet assembly for magnetic resonance imaging is used to generate the basic magnetic field with a strength needed to produce the steady state or equilibrium position of nuclei or nuclear spins in magnetic resonance imaging. This magnet, or a part thereof, is vibrated or tilted or otherwise periodically moved so as to change its position and thereby generate a time-varying gradient field, which is used to enter the acquired magnetic resonance signals as raw data into k-space.

Abstract: A magnetic resonance scanner has a base, a C-arm mounted on the base, the C-arm having an inner surface curved in a C-shape, the C-shape defining a plane, a magnet mounted on the inner curved surface of the C-arm, the magnet generating a basic magnetic field for magnetic resonance imaging, and a drive mechanism mechanically connected to the magnet. The drive mechanism rotates the magnet around an axis that is orthogonal to the plane so as to selectively position the magnet in at least two magnet positions that are respectively above and beneath a patient, who is situated in the C-arm along or parallel to the axis.

Abstract: A magnet assembly for magnetic resonance imaging is used to generate the basic magnetic field with a strength needed to produce the steady state or equilibrium position of nuclei or nuclear spins in magnetic resonance imaging. This magnet, or a part thereof, is vibrated or tilted or otherwise periodically moved so as to change its position and thereby generate a time-varying gradient field, which is used to enter the acquired magnetic resonance signals as raw data into k-space.

Abstract: A magnetic resonance scanner has a base, a C-arm mounted on said base, the C-arm having an inner surface curved in a C-shape, the C-shape defining a plane, a magnet mounted on said inner curved surface of said C-arm, the magnet generating a basic magnetic field for magnetic resonance imaging, and a drive mechanism mechanically connected to the magnet. The drive mechanism rotates the magnet around an axis that is orthogonal to said plane so as to selectively position said magnet in at least two magnet positions that are respectively above and beneath a patient, who is situated in the C-arm along or parallel to the axis.

Abstract: A system includes a magnetic resonance gradient accessory within an MRI system. The MRI system includes a magnet housing, a superconducting magnet generating a magnet field B0 to which a patient is subjected, shim coils, RF coils, receiver coils, magnetic gradient coils, and a patient table. The magnetic resonance gradient accessory creates local magnetic gradient fields critical to image generation and provides for diffusion encoding of a specific body region.

Abstract: Efficient encoding of signals in an MRI image is achieved through a combination of parallel receiver coils, and nonlinear gradient encoding that varies dynamically in such a manner as to impose a unique phase/frequency time varying signal on each pixel in the field of view. Any redundancies are designed such that they are easily resolved by the receiver coil sensitivity profiles. Since each voxel has an essentially identifiable complex temporal signal, spatial localization is easily achieved with only a single echo acquisition.

Abstract: Methods for correcting inhomogeneities of magnetic resonance (MR) images and for evaluating the performance of the inhomogeneity correction. The contribution of both transmit field and receiver sensitivity to signal inhomogeneity have been separately considered and quantified. As a result, their negative contributions can be fully corrected. The correction method can greatly enhance the accuracy and precision of MRI techniques and improve the detection sensitivity of pathophysiological changes. The performance of signal inhomogeneity correction methods has been evaluated and confirmed using phantom and in vivo human brain experiments. The present methodologies are readily applicable to correct signal intensity inhomogeneity artifacts produced in different imaging modalities, such as computer tomography, X-ray, ultrasound, and transmission electron microscopy.

Abstract: Efficient encoding of signals in an MRI image is achieved through a combination of parallel receiver coils, and nonlinear gradient encoding that varies dynamically in such a manner as to impose a unique phase/frequency time varying signal on each pixel in the field of view. Any redundancies are designed such that they are easily resolved by the receiver coil sensitivity profiles. Since each voxel has an essentially identifiable complex temporal signal, spatial localization is easily achieved with only a single echo acquisition.

Abstract: Methods for correcting inhomogeneities of magnetic resonance (MR) images and for evaluating the performance of the inhomogeneity correction. The contribution of both transmit field and receiver sensitivity to signal inhomogeneity have been separately considered and quantified. As a result, their negative contributions can be fully corrected. The correction method can greatly enhance the accuracy and precision of MRI techniques and improve the detection sensitivity of pathophysiological changes. The performance of signal inhomogeneity correction methods has been evaluated and confirmed using phantom and in vivo human brain experiments. The present methodologies are readily applicable to correct signal intensity inhomogeneity artifacts produced in different imaging modalities, such as computer tomography, X-ray, ultrasound, and transmission electron microscopy.

Abstract: In MRI by excitation of nuclear spins and measurement of RF signals induced by these spins in the presence of spatially-varying encoding magnetic fields, signal localization is performed through recombination of measurements obtained in parallel by each coil in an encircling array of RF receiver coils. Through the use of magnetic gradient fields that vary both as first-order and second-order Z2 spherical harmonics with position, radially-symmetric magnetic encoding fields are created that are complementary to the spatial variation of the encircling receiver coils. The resultant hybrid encoding functions comprised of spatially-varying coil profiles and gradient fields permits unambiguous localization of signal contributed by spins. Using hybrid encoding functions in which the gradient shapes are thusly tailored to the encircling array of coil profiles, images are acquired in less time than is achievable from a conventional acquisition employing only first-order gradient fields with an encircling coil array.

Abstract: In MRI by excitation of nuclear spins and measurement of RF signals induced by these spins in the presence of spatially-varying encoding magnetic fields, signal localization is performed through recombination of measurements obtained in parallel by each coil in an encircling array of RF receiver coils. Through the use of magnetic gradient fields that vary both as first-order and second-order Z2 spherical harmonics with position, radially-symmetric magnetic encoding fields are created that are complementary to the spatial variation of the encircling receiver coils. The resultant hybrid encoding functions comprised of spatially-varying coil profiles and gradient fields permits unambiguous localization of signal contributed by spins. Using hybrid encoding functions in which the gradient shapes are thusly tailored to the encircling array of coil profiles, images are acquired in less time than is achievable from a conventional acquisition employing only first-order gradient fields with an encircling coil array.