A system for minimizing MGI in a superconducting magnet system of an MRI system includes a thermal shield having bi-metal material. The thermal shield is configured to be disposed about a cold mass of the superconducting magnet system, wherein the bi-metal material is configured to minimize MGI.

The present invention provides a cryostat structure for a magnetic resonance imaging device and a magnetic resonance imaging apparatus comprising the same. The cryostat structure including: a casing which forms a ring-shaped chamber inside; a refrigerant container disposed in the chamber and housing a superconducting coil, so that the superconducting coil is immersed in the liquid refrigerant; a heat shield layer disposed between the casing and the refrigerant container for shielding heat radiation from the casing; the casing has a suction hole which is detachably sealed by a sealing cover, and an adsorption chamber is provided on one side of the casing facing the ring-shaped chamber, and an adsorbent capable of adsorbing overflowing elements from the casing or the refrigerant container or the heat shielding layer is contained in the adsorption chamber.

The present invention provides a method for compensation of periodic B.sub.0 modulations from a periodic motion of a cold head (212) of a main magnet (114) of a magnetic resonance (MR) imaging system (110), whereby main windings (200) of the main magnet (114) are cooled to superconductivity by the cold head (212), which exerts a repetitive motion, the method comprising the steps of measuring a periodic occurrence of spatial field components of the B-field based on a motion of the cold head (212) as a function of time, performing a sensor measurement of a periodic, auxiliary parameter of the MR imaging system (110), which is not the periodic occurrence of spatial field components, synchronizing the periodic occurrence of spatial field components of the B-field with the measured periodic, auxiliary parameter of the MR imaging system (110), and triggering based on the measured periodic sensor measurement of the MR imaging system (110) a periodic application of compensation signals to compensate the periodic occurrence of spatial field components of the B-field based on a motion of the cold head (212). Furthermore, the present invention provides a MR imaging system (110) for providing an image representation of a region of interest (142) of a subject of interest (120) positioned in an examination space (116) of the MR imaging system (110), wherein the MR imaging system (110) is adapted to perform the above method.

Described herein are systems, methods, and computer-readable medium for magnetic resonance (MR) based thermometry. In one aspect, in accordance with one embodiment, a method for magnetic resonance based thermometry includes: acquiring, by a variable flip-angle T1 mapping sequence, MR data in an area of interest of a subject that is heated by the application of focused ultrasound (FUS) to the brain of the subject, where the MR data includes T1 values over time, and where the acquisition of the MR data includes applying an accelerated three-dimensional ultra-short spiral acquisition sequence with a nonselective excitation pulse; and determining, based at least in part on a mathematical relationship established by T1 mapping thermometry, a temperature change in the area of interest over time, and where the temperature change is caused at least in part by a change in the applied FUS.

An apparatus includes: a getter material (310) disposed within a vacuum chamber (210) to absorb stray molecules within the vacuum chamber; a thermal mass (340) disposed adjacent the getter material and in thermal communication with the getter material; a cold station (312) disposed within the vacuum chamber above the thermal mass; and a convective cooling loop (310) connected between the thermal mass and the cold station and configured to convectively cool the thermal mass when the cold station is at a lower temperature than the thermal mass, and to thermally isolate the thermal mass from the cold station when the cold station is at a higher temperature than the thermal mass. The thermal mass may be water ice and may be thermally isolated from the walls of vacuum chamber by low loss support links (360, 362, 364) and/or thermal reflective shielding.

An assembly for thermal insulation of an MR magnet system during such a transport has a container for accommodating an MR magnet, the container being equipped with thermal insulation, and the container has an opening for accommodating a cooling unit. The assembly further has a protective cap, such that the opening is sealed in a reversible manner by the protective cap, and the protective cap is likewise equipped with thermal insulation.

A cooling system of a magnetic resonance apparatus is disclosed. In the cooling system, a first cooling device and a second cooling device are used to realize a secondary step of cooling of a circulating fluid without energy consumption, thereby reducing the operating energy consumption of the cooling system. In addition, a magnetic resonance apparatus comprising the cooling system is further provided.

A static magnetic field generator generates a non-magnetic field region. An AC magnetic field application instrument applies an AC magnetic field to the non-magnetic field region. A detection coil has an axis parallel to a direction of the AC magnetic field in order to detect a magnetization signal. A measuring instrument is connected to the detection coil. A resonance frequency variable device includes a capacitor connected in parallel to the detection coil in order to adjust a resonance frequency of the detection coil and the measuring instrument. A capacity of the capacitor is adjusted such that a resonance frequency of a closed circuit including the detection coil, the measuring instrument, and the resonance frequency variable device including the capacitor coincides with a frequency of a harmonic signal.

Systems and methods for magnetic field-dependent relaxometry using magnetic resonance imaging (“MRI”) are provided. Relaxation parameters, including longitudinal relaxation time (“T1”) and transverse relaxation time (“T2”), are estimated from magnetic resonance signal data acquired at multiple different magnetic field strengths using the same MRI system. By measuring these relaxation parameters as a function of magnetic field strength, T1 dispersion data, T2 dispersion data, or both, are generated. Based on this dispersion data, quantitative physiological parameters can be estimated. As one example, iron content can be estimated from T2 dispersion data.

A cryostat system is kept at a cryogenic operating temperature without providing or supplying cryogenic fluids by a cryocooler. The cryostat system includes a superconducting magnet arrangement and a heat sink apparatus to prolong the time before the superconducting magnet arrangement quenches/returns to the normally conducting state if active cooling fails. The heat sink apparatus includes magnetocaloric material and is thermally connected to the superconducting magnet arrangement and/or to parts of the cryostat system through which ambient heat can flow to the superconducting magnet arrangement. In this way, the cryostat system can be operated in a truly “cryogen-free” manner while maintaining a sufficiently long time to quench in the event of potential operational malfunctions.