Abstract: A compact, lightweight, and easy-to-use ESR-CT apparatus including a magnetic field leak line (5-G line) which is capable of imaging a small animal, such as a mouse, within 15 minutes, and of observing a desired region with a spatial resolution of 1 mm or less. A permanent magnet system is introduced of the apparatus includes pole pieces having a predetermined area which are opposed to each other through a measured space, yokes combined with the pole pieces, and a permanent magnet inserted in series so that at least one magnetic pole plane intersects perpendicularly to the closed magnetic circuit for magnetic coupling with the yokes. This makes it possible to locate a gradient coil system and a field scanning coil system sufficiently apart from end faces of the pole pieces, and to downsize the field scanning coil system so that the gradient field system is movable.

Abstract: In a method for adjustment of a shim device of a magnetic resonance apparatus before an image acquisition in a body region that has a volume of interest, a field distribution is measured in a region encompassing the volume of interest produced with a shim device set according to a basic shim data set. A shim data set that is optimized for the volume of interest is determined by a control device starting from the basic shim data set, dependent on the field distribution; and the optimized shim data set is used for adjustment of the shim device. The basic shim data set is selected from a databank of body region-specific input shim data sets.

Abstract: A magnetic resonance apparatus has a magnetic field generation device for generating a strong magnetic field, and at least one detection device for automatic detection of an object attracted onto or into the magnetic resonance apparatus due to interaction with the magnetic field.

Abstract: A magnetic shielding apparatus having a high shielding effect. With the magnetic shielding apparatus having an opening (for example, a cylindrical magnetic shielding apparatus provided with a door), the door covering the opening is electrically and/or magnetically connected to a main body by means of electrically and/or magnetically connecting members. The magnetic shielding apparatus is higher in magnetic shielding factor than the conventional magnetic shielding apparatus, and a magnetic field measuring apparatus using the magnetic shielding apparatus, capable of measuring biomagnetism generated from an inspection target (a living body), with higher sensibility than before.

Abstract: A first sensor of the device for compensating magnetic and/or electromagnetic disturbance fields in a predetermined volume range is provided beyond the predetermined volume range for producing a signal that is determined by the magnetic and/or electromagnetic field at the location of the sensor. A second sensor is provided within the predetermined volume range for producing a signal which is determined by the magnetic and/or electromagnetic field at the location of the sensor. The signals from the first and second sensors are used as an input signal for directing a regulator amplifier belonging to a Helmholtz coil. After executing an empirically determined transmission function, the signal from the second sensor is applied to the regulator input of the digital regulator amplifier and the output signal of the digital regulator amplifier controls the current through the Helmholtz coil such that the magnetic and/or electromagnetic field in the predetermined volume range is at least partially compensated.

Abstract: A method for reducing B0 inhomogeneous effects in magnetic resonance imaging (MRI). The method includes: obtaining a high-resolution volumetric MR image of the patient, such high-resolution volumetric MR image having B0 inhomogeneous effects; calculating distortion within obtained the high-resolution volumetric MR image of the patient; and correcting the B0 inhomogeneous effects in the obtained high-resolution volumetric image using the calculated distortion.

Abstract: A magnetic resonance imaging apparatus includes a collector which collects magnetic resonance signals emitted from a region of interest of a subject, and a correction magnetic field generator which generates a correction magnetic field to correct the nonuniformity of a static magnetic field on the basis of magnetic resonance signals which are contained in the magnetic resonance signals collected by the collector, are emitted from a specific region which forms a portion of the region of interest.

Abstract: The invention concerns a magnet configuration comprising a superconducting magnet coil (1) within which a gradient system is to be switched. All low temperature oscillation systems (R1) with a temperature T1<10K within the magnet coil (1) are produced from a material having good electrical conducting properties, and at least one warm oscillation system (R2) with a temperature T2>10K within the magnet coil (1) has worse electrical conducting properties and has a considerably different mechanical resonance frequency (separation approximately 500 Hz or more) than at least one of the low temperature oscillation systems (R1). This reduces the undesired heating power supplied to the low temperature oscillation systems due to mechanical oscillations and induced eddy currents.

Abstract: A magnetic resonance apparatus has a gradient coil unit with passive shim devices inserted into side receptacles in the molded body of the gradient coil unit. Each shim device has a carrier with a number of metal elements, the metal elements being mounted on the carrier in linear succession and being situated essentially orthogonally to the longitudinal axis of the carrier.

Abstract: A magnetic resonance imaging scanner includes a magnet (20) generating a temporally constant magnetic field, magnetic field gradient-generating structures (30) superimposing selected magnetic field gradients on the temporally constant magnetic field, and a radio frequency coil (32) producing a radio frequency field. A magnetic field-modifying structure (60) disposed inside a radio frequency shield (64) includes dispersed particles of magnetic material (701, 702, 703, 704) that enhance the temporally constant magnetic field. The particles are generally smaller in at least one dimension than a skin depth of the radio frequency field in the magnetic material. The magnetic field-modifying structure has a longitudinal demagnetization factor (Nz) parallel to the temporally constant magnetic field and a tangential demagnetization factor (NT) in a tangential direction transverse to the temporally constant magnetic field.

Abstract: A superconducting magnet of the present invention includes a switching element that closes its output side (operation side) when the voltage on its input side is smaller than a predetermined value and opens the output side when the voltage on the input side is larger than the predetermined value, wherein the input side is connected in parallel to a main coil circuit, and the output side of is connected in series to external magnetic-field disturbance compensation coils, for releasing the circuit of the disturbance compensation coil by closing the output side if the voltage on the input side is smaller than the predetermined value.

Abstract: A method for compensating in a space volume for a magnetic noise field outside the space volume includes determining a strength of the magnetic noise field outside the space volume; defining a correlation between the noise field outside the space volume and a corresponding noise field inside the space volume, or calculating the noise field inside the space volume on the basis of the measurements of the magnetic field outside the space volume; based on the noise field inside the space volume, generating a magnetic compensation field for neutralizing the noise field inside the space volume; wherein the compensation of the magnetic noise field outside the space volume is carried out along a direction in the space volume which is variable by determining a noise field component inside the space volume along the direction and generating a compensation field of the noise field component along the direction.

Abstract: A method for determining construction parameters of magnet structures designed to generate magnetic fields in predetermined volumes of space, comprising the steps of: a) defining a predetermined volume of space in which a static magnetic field is to be generated; b) defining the nominal strength and profile of the magnetic field in said predetermined volume of space; c) mathematically describing the nominal magnetic field on the surface of and/or in said predetermined volume of space by using a polynomial expansion of the magnetic field-describing function, which provides a series of coefficients; d) determining the size, geometry and relative position in space of the means for generating said nominal magnetic field, with respect to the volume of space in and on which the desired, i.e. nominal magnetic field, is defined.

Abstract: A magnetic field generating assembly comprising a set (A1-A3;B1-B3;C1-C3) of, typically substantially coaxial, coils substantially symmetrically arranged about a plane orthogonal to the axis. At least some of the coils carry working currents in the opposite sense to the other coils The arrangement of turns and working currents carried by the coils is such that a first working volume (10) with a substantially homogeneous magnetic field is generated within the envelope defined by the assembly, and two second working volumes (11) each with a substantially homogeneous magnetic field are generated outside the envelope, the homogeneity of each of the first and second working volumes being sufficient to perform a NMR experiment on a sample in the working volume.

Abstract: A shim support guide jig includes a shim support guide pipe in which a guide passage for guiding the movement of a shim support is formed. In a state where a superconducting magnet has generated a static magnetic field, the designated shim support can be drawn out from the internal space of the superconducting magnet through the guide passage, and the designated shim support for which magnetic material shims have been arranged and adjusted can be inserted into the internal space through the guide passage. A magnetic field generation apparatus has the magnetic material shims arranged and adjusted using the shim support guide jig, and a magnetic resonance imaging equipment employs the magnetic field generation apparatus. Magnetic field adjustment methods for the magnetic field generation apparatus and for the magnetic resonance imaging equipment are performed using the shim support guide jig.

Abstract: Disclosed is a vacuum housing for a magnetic resonance apparatus having a recess for leading through lead wires to elements located inside the vacuum housing, and a first lead-through bushing module. The first lead-through bushing module is provided with a first closing plate which is configured so as to vacuum-tightly seal the recess along with a second closing plate. The first bushing module is also provided with a first structural component that is to be at least partially led through the recess during assembly of the lead-through bushing module and whose size defines a minimum size of the recess, which is greater than the size of the first closing plate.

Abstract: A magnetic resonance imaging apparatus capable of suppressing noise caused by vibration of a gradient magnetic field coil and improving image quality is realized. A shim tray 22 is disposed between a static magnetic field generating magnet 4 and a gradient magnetic field generating coil 13. A large number of ferromagnetic shims are disposed in a large number of holes (screw holes) 24 formed in the shim tray 22. Vibration dampers 23 are disposed in holes formed in the shim tray 22 to reduce noise generated by vibration of the gradient magnetic field generating coil 13, which is propagated to the static magnetic field generating magnet through solid bodies and shakes the static magnetic field generating magnet, etc. It is hence possible to secure areas for arrangement of two means, i.e.

Abstract: A method of providing shim sheets for adjusting a magnetic field in a magnetic resonance device by passive shimming, comprises the steps of field mapping of a region of interest in the MR device for obtaining an uncorrected magnetic field distribution including field inhomogeneities, decomposing the field inhomogeneities into first and second order spherical harmonic functions, determining primary shim terms derived from the second order spherical harmonic functions, wherein the primary shim terms yield a passive shim field adapted to a targeted shim field, scaling optimized shim terms for increasing a similarity of the passive shim field with the targeted shim field, constructing modular shim sheets on the basis of the optimized shim terms, and mounting the modular shim sheets on a shim sheet carrier of the magnetic resonance device. Furthermore, an adjustment device for adjusting a magnetic field in a magnetic resonance device by passive shimming is described.

Abstract: To achieve a good balance among the magnetic field intensity, region of homogeneous magnetic field intensity and cost, a magnetic field generating apparatus for generating a magnetic field in a vertical direction comprises: a pair of magnets having respective magnetic poles with mutually opposite polarities disposed to face each other in a vertical direction, for generating a static magnetic field having different dimensions of its region of homogeneous magnetic field intensity in two mutually orthogonal directions in a horizontal plane; a pair of planar magnetic elements, each element supporting respective one of the pair of the magnets; and a vertical columnar magnetic element lying in a direction different from the two directions, each end of which is joined to respective one of the pair of the planar magnetic elements.

Abstract: A magnetic field adjustment device for a superconducting magnet, wherein magnetic material shim mechanisms are arranged in an axial direction of an inside periphery of the cylindrical superconducting magnet, each of the magnetic material shim mechanisms including a combined shim tray (14 in FIG. 2) in which a plurality of divided shim trays (11 and 12) and shim tray spacers (13) inserted between the divided shim trays are rectilinearly coupled, and magnetic material shims (101) for magnetic field adjustments as are accommodated in the divided shim trays. The magnetic material shim mechanisms afford a high versatility of magnetic material shim arrangements, whereby a correctable range of a magnetic field uniformity can be widened.

Abstract: A magnetic resonance imaging method comprising a step for applying one or more gradient magnetic field pulses continuously, a step for calculating a residual magnetic field being generated from a magnet by an gradient magnetic field pulse based on a residual magnetic field response function representing the relation between the strength of the gradient magnetic field pulse being applied and the strength of a residual magnetic field being generated, and a step for correcting the residual magnetic field thus calculated. The magnetic resonance imaging method is further provided with a step for updating the residual magnetic field response function with time depending on the application history of the gradient magnetic field pulses being applied continuously.

Abstract: An arrangement for producing an imaging region of increased maximum radial diameter in a magnetic resonance imaging (MRI) system, comprising a solenoidal magnet arrangement (30) comprising primary magnet coils (32) arranged symmetrically about an axis (A-A) and a shim coil set.

Abstract: The present invention discloses a novel self-fastening cage of a magnetic resonance device (MRD) (100) for providing a homogeneous, stable and uniform magnetic field therein, characterized by an outside shell comprising at least three flexi-jointed superimposed walls (1). In a technology of self-fastening cage, the invention teaches an effective multi-streamed MRD comprising a cage including a closed magnetic circuit constructed from strong permanent magnets; and an optional shimming mechanism selected from an array of active shim coils, passive shimming elements or any combination thereof; a contained cavity within which the magnetic field strength is approximately uniform; and a means, such as a plurality of conveyor belts, pipes or any other transportation means by which a plurality of samples are introduced into the region of uniform magnetic field; such that magnetic resonance measurements are made on a plurality of samples within the region of uniform magnetic field.

Abstract: A magnetic shimming configuration for a high-field magnet having optimized turn geometry and electrical circuitry. The present invention accomplishes this by combining the corrective functionalities of the standard X and ZX shims into two single, simplified electrical circuits and conductors, optimized for field strength as a function of turn location. The standard Y and ZY shims were also replaced with two single, simplified circuits and conductor that is corrective of the Y and ZY fields. The new configuration also eliminates the need of additional “second, outboard turns” of the traditional X, ZX, Y, and ZY shims, located further away from the mid-plane.

Abstract: A field distribution correction element for positioning on an examination subject in a magnetic resonance system for local influencing of the radio-frequency field distribution during a magnetic resonance acquisition has a system of electrically conductive dipole strips essentially running in parallel, arranged on a carrier element. In a corresponding method for generation of magnetic resonance exposures of an examination subject in a magnetic resonance system, for local influencing of the radio-frequency field distribution, such a field distribution correction element is positioned on the patient.

Abstract: A permanent magnet assembly for an imaging apparatus having a permanent magnet body having a first surface and a stepped second surface which is adapted to face an imaging volume of the imaging apparatus, wherein the stepped second surface contains at least four steps.

Abstract: [PROBLEMS] A magnetic resonance imaging apparatus in which vibration of a gradient magnetic field coil is reduced, the vibration is not transmitted to a static magnetic field correcting unit, and the space can be saved. [MEANS FOR SOLVING PROBLEMS] A tabular gradient magnetic field generating unit is placed over each opposing surface of support member therebetween. A static magnetic field correcting unit for correcting the uniformity of the static magnetic field is placed between the static magnetic field generating unit and the gradient magnetic field generating unit. The static magnetic field correcting unit is a tabular shim tray provided with magnetic body pieces for correcting the uniformity of the static magnetic field, and is placed over each of the pair of the opposing surfaces of static magnetic field generating units, with a second supporting member therebetween.

Abstract: The invention provides tools and methods for shimming magnets such as MRI and NMR magnets, while at field. The invention provides safe methods for shimming at field. The invention particularly provides a tool (40) for withdrawing and inserting a shim tray (7) into slots (34) in a magnet (30), in the presence of a magnetic field. The tool comprises a channel (11, 12) for guiding a shim tray, alignment means (64, 74, 76, 6) for aligning the channel with a selected slot, a drive means (9) arranged to propel a shim tray along the channel; and a connector (96) arranged to detachably link the drive means to a shim tray.

Abstract: Magnetic resonance apparatus is provided comprising a magnet having a first pair of coils arranged in a plane. The coils are operable in a counter-running manner when in use so as to generate a sensitive volume of magnetic field spaced apart from said plane. The magnetic field in the sensitive volume is arranged to have sufficient uniformity to enable magnetic resonance signals to be obtained from a target when located within the sensitive volume. The magnetic field direction Z is oriented to lie substantially parallel to the planes. The coils are arranged such that the sensitive volume is elongate in a direction X substantially parallel to the planes. A drive system is provided to cause relative movement between the magnet and the target so as to allow the sensitive volume to be moved with respect to the target.

Abstract: In a method and magnetic resonance apparatus wherein a homogenous magnetization is generated in a spatial examination volume of the apparatus during examination of a subject, individual resonator segments of a body coil, that are electromagnetically decoupled from each other, are separately activated by a control and evaluation device according to sets of predetermined segment-specific excitation parameters stored in the control and evaluation device. The resonator segments are temporally sequentially excited in an excitation sequence, using different excitation parameter sets with phase distributions of the nuclear magnetization distributions in the examination volume constructively superimposing to form a resulting homogenous entire nuclear magnetization distribution in the examination volume.

Abstract: In a magnetic resonance imaging system (10), a main magnet (20) generates a substantially uniform main magnetic field (B0) through an examination region (14). An imaging subject (16) generates inhomogeneities in the main magnetic field (B0). One or more shim coils are positioned adjacent a gradient coil (26). The gradient coil (26) is driven in halves by first and second power sources (28, 30) which have slightly dissimilar power characteristics which induce an inductive coupling between the shim coil (60) and the gradient coil (26). The shim coil (60) is designed to produce a desired magnetic field, such that the inductive coupling of the shim coils (60) to the gradient coil (26) is substantially minimized while the inhomogeneities in the main magnetic field (B0) caused by the imaging subject are corrected based on prespecified spatial characteristics.

Abstract: Magnetic resonance apparatus is provided comprising a magnet having a plurality of pairs of coils arranged in respective substantially parallel planes. The coils in each pair are operable in a counter-running manner when in use so as to generate a region of magnetic field spaced apart from said planes, having sufficient uniformity to enable magnetic resonance signals to be obtained from a target within the region. The magnetic field has a magnetic field direction Z lying substantially parallel to said planes and each of the coils is elongate in a direction X substantially parallel to said planes.

Abstract: A method for homogenizing a static magnetic field with a magnetic field distribution B0(r) for nuclear magnetic resonance spectroscopy by adjusting the currents Ci through the shim coils, thus creating spatial field distributions Ci·Si(r), where r stands for one, two, or three of the spatial dimensions x, y, and z, and said magnetic field distribution B0(r) has only a field component along z, in a working volume of a magnetic resonance apparatus with one or more radio frequency (=RF) coils (5) for inducing RF pulses and receiving RF signals within a working volume, said RF coils having a spatial sensitivity distribution of magnitudes B1k(r), and with shim coils (6) for homogenizing the magnetic field within the working volume, said shim coils (6) being characterized by their magnetic field distributions per unit current Si(r) and having components only along z, includes the following steps: (a) Mapping the magnetic field distribution B0(r) of the main magnetic field, (b) calculating a simulated spectrum IS

Abstract: Magnetic resonance systems are provided which employ a shielded, asymmetric magnet to produce an offset dsv. The magnets include at least a first coil C1, which carries current in a first direction, and two coils C2 and C3, which are located at least in part within the internal envelope EC1 defined by the first coil and which carry current in an opposite direction to the first coil. The magnets are shielded by a shielding coil C4, which carries current in a direction opposite to that of the first coil, and/or a ferromagnetic structure (FS). The magnets can include additional coils, such as a fifth coil C5 at the magnet's distal end. The magnets can be used in, for example, orthopedic imaging.

Abstract: In a shim board system with at least one shim board formed by an insulating substrate and at least one conductor trace on the substrate for generation of a shim magnetic field, in particular for homogenization of the basic magnetic field of a magnetic resonance apparatus, the insulating substrate is fashioned as a mesa in at least one segment similar to the conductor trace and following the curve of the conductor trace. Upon sealing, this allows a good saturation of the shim board system with sealing compound.

Abstract: The present invention provides a permanent magnet, comprising a cylinder formed with a permanent magnetic material. The cylinder comprises along a radial direction, a magnetic core and a magnetic sheath that are coaxial. The magnetic core is assembled in the magnetic sheath. The magnetization direction of the magnetic core is axial direction, and the magnetization direction of the magnetic sheath changes step by step from a direction which is parallel to the magnetization direction of the magnetic core in one end to a direction which is orthogonal to the magnetization direction of the magnetic core in the other end, along the axial direction of the cylinder. Moreover, a magnetic device for use in MRI using the magnet and manufacturing methods for the permanent magnet and the magnetic device are also provided in the present invention. With the permanent magnet, magnetization strength in the working area generated by the magnetic device for use in MRI can amount to more than 0.5-0.6 T.

Abstract: A method is disclosed for measuring whole body composition. The method includes confining movement of the body to a selected volume, inducing a static magnetic field in the volume, inducing a pulsed radio frequency magnetic field in the volume, and receiving nuclear magnetic resonance signals from the body. The resonance signals from any part of the body are substantially independent of a position of the body part within the volume. Whole body composition is assessed from the resonance signals.

Abstract: A magnetic resonance apparatus in which magnetic metal pieces are accommodated in an accommodation section so as to correct uniformity in a main magnetic field, includes an acquisition unit which acquires temperature information related to at least one of a temperature of the magnetic metal pieces accommodated in the accommodation section, a temperature of the accommodation section, and a temperature of a position in the vicinity of the accommodation section, and a temperature adjustment unit which adjusts the temperature of the magnetic metal pieces to a target temperature by preheating the magnetic metal pieces on the basis of the temperature information acquired by the acquisition unit.

Abstract: To achieve a good balance among the magnetic field intensity, region of homogeneous magnetic field intensity and cost, a magnetic field generating apparatus for generating a magnetic field in a vertical direction comprises: a pair of magnets having respective magnetic poles with mutually opposite polarities disposed to face each other in a vertical direction, for generating a static magnetic field having different dimensions of its region of homogeneous magnetic field intensity in two mutually orthogonal directions in a horizontal plane; a pair of planar magnetic elements, each element supporting respective one of the pair of the magnets; and a vertical columnar magnetic element lying in a direction different from the two directions, each end of which is joined to respective one of the pair of the planar magnetic elements.

Abstract: An NMR probe head for investigating a temperature-sensitive test object in a volume under investigation with at least one RF receiver coil which is cooled to cryogenic temperatures during operation, and is surrounded by a housing, wherein at least one heatable separating wall is provided between the RF receiver coil and the test object, is characterized in that the separating wall is produced from a material having excellent heat conducting properties, wherein the separating wall is coupled in a heat conducting fashion to at least one heating element at a separation from the volume under investigation via at least one contact location. The inventive NMR probe head permits disposition of the RF receiver coil in close proximity to the test object to be measured without inadvertently cooling it.

Abstract: A method for generating an estimate of inhomogeneity includes generating a first estimate of inhomogeneity, generating a second estimate of inhomogeneity, and generating a final estimate of inhomogeneity using at least the first and second estimates.

Abstract: Eddy current generated around a magnetic circuit in an MRI apparatus is one of the causes of deviation from an ideal magnetic field gradient waveform and causes image distortion, loss of strength, ghost generation, loss of signal, and spectral distortion. An object of the present invention is to suppress the generation of the eddy current. In an MRI apparatus, a ferromagnetic material formed from powder is used in a part of a magnetic circuit: the powder mainly comprising a mother phase containing iron or cobalt and showing ferromagnetism; and a high-resistance layer having a resistance not less than ten times as high as the mother phase and a Vickers hardness lower than that of the mother phase being formed in layers along parts of the surface of the powder on parts or the entire of the surface.

Abstract: Asymmetric radio frequency (RF) coils for magnetic resonance applications are provided. Also provided are time harmonic methods for designing such coils as well as symmetric coils. In addition, methods for converting complex current density functions into discrete capacitive and inductive elements are provided.

Abstract: A magnetic resonance imaging method comprising a step for applying one or more gradient magnetic field pulses continuously, a step for calculating a residual magnetic field being generated from a magnet by an gradient magnetic field pulse based on a residual magnetic field response function representing the relation between the strength of the gradient magnetic field pulse being applied and the strength of a residual magnetic field being generated, and a step for correcting the residual magnetic field thus calculated. The magnetic resonance imaging method is further provided with a step for updating the residual magnetic field response function with time depending on the application history of the gradient magnetic field pulses being applied continuously.

Abstract: A method of providing shim sheets for adjusting a magnetic field in a magnetic resonance device by passive shimming, comprises the steps of field mapping of a region of interest in the MR device for obtaining an uncorrected magnetic field distribution including field inhomogeneities, decomposing the field inhomogeneities into first and second order spherical harmonic functions, determining primary shim terms derived from the second order spherical harmonic functions, wherein the primary shim terms yield a passive shim field adapted to a targeted shim field, scaling optimized shim terms for increasing a similarity of the passive shim field with the targeted shim field, constructing modular shim sheets on the basis of the optimized shim terms, and mounting the modular shim sheets on a shim sheet carrier of the magnetic resonance device. Furthermore, an adjustment device for adjusting a magnetic field in a magnetic resonance device by passive shimming is described.

Abstract: An exemplary method for correcting inhomogeneities of the static magnetic field generated by the magnetic structure of a machine for acquiring nuclear magnetic resonance images includes determining the number, the position and the magnetic moment of dipoles compensating inhomogeneities of the magnetic field to be positioned on a positioning grid such that a function is minimized. The total magnetic moment of compensation dipoles for compensating the magnetic field inhomogeneity can be minimized in addition to minimizing a norm of the difference between an inhomogeneity vector of each of the magnetic field components and the linear combination of effect vectors corresponding to the magnetic field component of compensation dipoles.

Abstract: A matrix shim system for generating magnetic field components superimposed on a main static magnetic field, comprising a plurality of annular coils, is characterized in that it comprises g groups G1 . . . Gg of coils, with g being a natural number ?1, wherein each group Gi consists of at least two single annular coils connected in series, wherein each group Gi is designed to generate, in use, a magnetic field B z ? ( G i ) = ? n = 0 ? ? A n ? ? 0 ? ( G i ) · T n ? ? 0 . For each group Gi, there are at least two values of n for which ? A n ? ? 0 ? ( G i ) · R n ? max ? { ? A 20 ? ( G i ) · R 2 ? , … ? , ? A N ? ? 0 ? ( G i ) · R N ? } ? 0.5 ? ? and ? ? N ? n ? 2 , with N: the total number of current supplies of the matrix shim system, and R: smallest inside radius of any of the annular coils of the matrix shim system.

Abstract: In a magnetic resonance imaging apparatus and a method for shimming such an apparatus, at each of mirror-symmetrical assemblies respectively disposed at opposite faces of a static magnetic field generator, that each include a shimming ring, an additional shimming ring is provided that is adjustable in position relative to the other shimming ring to shim the static magnetic field. Additionally or alternatively, at each face of the static magnetic field generator, a permanently magnetic arrangement is provided that is divided into a number of permanently magnetic columns respectively having different energy levels. Additionally or alternatively, magnetic bolts, such as magnetically conducting bolts or permanently magnetic bolts can be symmetrically inserted into either of the mirror-symmetric assemblies, or the permanently magnetic columns, for additionally shimming adjustment.

Abstract: A cold mass for a superconducting magnet system in one example comprises a superconducting magnet, a cryogenic cooling circuit, and a magnet and cooling circuit support. The magnet and cooling circuit support comprises a substantially conductive coupler in a discrete path that serves to couple the superconducting magnet and the cryogenic cooling circuit.

Abstract: A magnetic resonance imaging apparatus includes an array coil in which a plurality of element coils are arranged to receive magnetic resonance signals from a subject, a calculation unit which calculates projection data for the element coils regarding an arrangement direction of the plurality of element coils on the basis of the plurality of magnetic resonance signals received by the plurality of element coils, and a determination unit which determines the positions of the plurality of element coils or the position of the array coil on the basis of the projection data for the plurality of element coils.