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.

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.

An electronic device (10) includes an electronic component (14); at least one electrically conductive loop or winding (18) disposed around the electronic component; and an electronic controller (24) configured to: obtain (102) a magnetic field direction from a received ambient magnetic field measurement signal; determine (104) at least one magnetic field shim current based on the obtained magnetic field direction; and energize (106) the at least one electrically conductive loop or winding to flow the determined at least one magnetic field shim current.

An electronic device (10) includes an electronic component (14); at least one electrically conductive loop or winding (18) disposed around the electronic component; and an electronic controller (24) configured to: obtain (102) a magnetic field direction from a received ambient magnetic field measurement signal; determine (104) at least one magnetic field shim current based on the obtained magnetic field direction; and energize (106) the at least one electrically conductive loop or winding to flow the determined at least one magnetic field shim current.

Devices for determining a state of a magnetic field-generating article are provided. In various embodiments, a device comprises: a single crystal diamond having a plurality of NV centers, the single crystal diamond configured to be disposed adjacent to a magnetic field-generating article, and configured to generate a fluorescent signal in response to being illuminated by a light source; a coherent light source configured to generate a light beam directed at the single crystal diamond; a microwave (MW) radiation source configured to irradiate the single crystal diamond with a MW signal; a magnetic field source configured to apply a bias magnetic field to the single crystal diamond; a photosensor configured to collect the fluorescent signal generated by the single crystal diamond; and a computing node operatively coupled to each of the coherent light source, the MW radiation source, the magnetic field source, and the photosensor.

Devices for determining a state of a magnetic field-generating article are provided. In various embodiments, a device comprises: a single crystal diamond having a plurality of NV centers, the single crystal diamond configured to be disposed adjacent to a magnetic field-generating article, and configured to generate a fluorescent signal in response to being illuminated by a light source; a coherent light source configured to generate a light beam directed at the single crystal diamond; a microwave (MW) radiation source configured to irradiate the single crystal diamond with a MW signal; a magnetic field source configured to apply a bias magnetic field to the single crystal diamond; a photosensor configured to collect the fluorescent signal generated by the single crystal diamond; and a computing node operatively coupled to each of the coherent light source, the MW radiation source, the magnetic field source, and the photosensor.

A method of operating a magnetic resonance imaging (MRI) apparatus includes exciting a body coil of the MRI apparatus to emit a radio-frequency signal, determining a center frequency of a resonance curve of the body coil, and calculating a magnet target frequency based on the determined center frequency. A magnet is ramped to the magnet target frequency.

A method, device, and system for reducing inhomogeneity in an imaging magnetic field during magnetic resonance imaging is described. The method includes generating a corrective magnetic field during imaging, the corrective magnetic field having a first magnetic field component and a second magnetic field component with a phase separation therebetween. The first and second components are generated according to a stability parameter decomposed from a stability field that correct an instability identified within the imaging magnetic field.

Systems and methods are provided for multiphotonic magnetic resonance imaging. The system uses one or more (B.sub.1,z) RF coils or oscillating gradients oriented along the z-axis to provide multiphoton resonances. The B.sub.1,z coils can be implemented as planar coils or solenoids. With the additional coils, standard slice-selective pulse sequences have all standard excitations replaced with multiphoton excitations that excite extra resonances. In vivo imaging using multiphoton excitation has signal to noise ratios comparable to single-photon excitations when similar pulse sequences are used. Since excitation is not bound to the Larmor frequency, new RF pulse sequences can be designed with imaging methods patterned after single-photon excitation concepts.

Systems and methods are provided for multiphotonic magnetic resonance imaging. The system uses one or more (B.sub.1,z) RF coils or oscillating gradients oriented along the z-axis to provide multiphoton resonances. The B.sub.1,z coils can be implemented as planar coils or solenoids. With the additional coils, standard slice-selective pulse sequences have all standard excitations replaced with multiphoton excitations that excite extra resonances. In vivo imaging using multiphoton excitation has signal to noise ratios comparable to single-photon excitations when similar pulse sequences are used. Since excitation is not bound to the Larmor frequency, new RF pulse sequences can be designed with imaging methods patterned after single-photon excitation concepts.