Abstract: A configurable matrix receiver comprises a plurality of antennas that detect one or more signals. The antennas are coupled to a configurable matrix comprising a plurality of amplifiers, one or more switches that selectively couple the amplifiers in series fashion, and one or more analog-to-digital converters (ADCs) that convert the output signals generated by the amplifiers to digital form. For example, in one embodiment, a matrix comprises a first amplifier having a first input and a first output, and a second amplifier having a second input and a second output, a switch to couple the first output of the first amplifier to a the second input of the second amplifier, a first ADC coupled to the first output of the first amplifier, and a second ADC coupled to the second output of the second amplifier. In one embodiment, the signals detected by the antennas include magnetic resonance (MR) signals.

Abstract: A current lead for the superconducting magnet of a magnetic resonance system, the superconducting magnet being refrigerated by a cold head, has a positive current lead and a negative current lead electrically connected to the superconducting magnet for magnetization thereof. The cold head is electrically connected to the superconducting magnet and is used as one of the positive and negative current leads. The cold head is used as the positive current lead or the negative current lead so as to reduce the number of current leads as well as the heat conducted by the current lead, therefore it maintains a stable superconducting environment more efficiently. Furthermore, the cold head and the current lead can be provided in the same conduit without the need to design a separated turret tube and side tube, and the structure of the current leads of the superconducting magnet of the magnetic resonance system is simplified.

Abstract: An improved magnetic resonance (MR) imaging system (10) is provided. A plurality of receiver coils (12) may be configured to supply respective coil output signals based on a plurality of magnetic resonance response signals sensed by the receiver coils. Each receiver coil defines an enclosure constituting a Faraday cage. At least one circuit device (22) is disposed in the enclosure (24) to condition the coil output signal. This enclosure enables the circuit device (22) to be shielded from electromagnetic interference.

Abstract: In order to produce field strength gradients (x,y) for a NMR machine, the curve-shaped gradients are substituted by coils arraigned in tubes. Said tubes are distributed on the annular circumference (6) of the examination space of the tunnel NMR machine. Said invention makes it possible to produce at request field strength gradients in all necessary directions by providing each tube with the same set of coil elements and supplying them with selected currents.

Abstract: A method and apparatus for actively controlling quench protection of a superconducting magnet includes a magnetic resonance imaging (MRI) system and a computer readable storage medium having stored thereon a computer program comprising instructions which when executed by a computer cause the computer to detect a quench condition of the superconducting magnet. The instructions also cause the computer to actively control a quench protection system of the superconducting magnet in response to the detected quench condition.

Abstract: A magnetic resonance imaging (MRI) device for imaging a volume includes a main magnet for generating a magnetic field, an insulator sheet formed into a tube extending along an axis, a gradient coil disposed on an outside surface defining the tube for manipulating the magnetic field generated by the main magnet to image the volume, and a cooling circuit disposed between the gradient coil and a RF coil. The cooling circuit is disposed on an opposite inside surface defining the tube, wherein the cooling circuit shields the gradient coil from the RF coil while cooling the gradient coil.

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: An iterative method determines a spatial distribution of values of a property of an object, and particularly values of its absorption, in an examination region, on the basis of measured values that values are acquired with a measuring device, and particularly with a computer tomograph. The reliability of each measured value is taken into account when this is done. The measured values can each be represented as a sum of values of the property that have each been multiplied by a proportional factor, the proportional factor being a measure of the proportion that a value of the property forms of the measured value.

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 magnetic assembly for a nuclear magnetic resonance apparatus includes a number of primary permanent magnets 1 disposed in an array about a longitudinal axis, the arrangement and/or characteristics of the plurality of magnets being such so as to create a zone of homogeneous magnetic field at some location along the axis forward of the array (and into the material when provided). A secondary permanent magnet 7 may be located along the longitudinal axis within the array of primary magnets and may be moveable. The primary magnets 1 have a north pole and a south pole with an axis therebetween, and may be arranged such that the axis between the poles is at an angle to the longitudinal axis.

Abstract: A vacuum vessel assembly includes an inner cylinder and an outer cylinder formed of a material in which eddy currents are substantially not produced. The inner cylinder includes a first and second half having an annular flange thereon. A plurality of metal interfaces are connected to the inner cylinder and the outer cylinder. The plurality of metal interfaces bond the first half and second half of the inner cylinder and also bond the inner cylinder to the outer cylinder.

Abstract: In a superconducting magnets for MRI configured to generate a homogeneous magnetic field and a gradient magnetic field in a space between a top superconducting magnet and a bottom superconducting magnet, the bottom superconducting magnet is provided with a supporting member that supports a helium vessel, and the supporting member is fixed to a vacuum vessel of the bottom superconducting magnet at one end, and is fixed to the floor surface in the vicinity of the end fixed to the vacuum vessel. A high-quality MR image can be thus obtained by preventing direct transmission of oscillation of the gradient coils to the superconducting magnet and reducing oscillation of the gradient coils while achieving a reduction of the overall superconducting magnet in size.

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: The present invention relates to devices and method for dissolving solid polarised material while retaining a high level of polarisation. In an embodiment of the present invention a material is polarised in a strong magnetic field in a cryostat 2 and then brought into solution while still inside the cryostat 2.

Abstract: The present invention relates to a magnetic resonance imaging (MRI) device. The basic components of an MRI device are the main magnet system (2), the gradient system (3), the RF system and the signal processing system. According to the present invention, the magnetic resonance imaging (MRI) device has an eddy current shield system, wherein the eddy current shield system comprises at least one perforated eddy current screen (13, 14), and wherein the or each perforated eddy current screen (13, 14) is assigned to the main magnet system (2).

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 magnet assembly comprising first and second sets of coils (1, 2) for generating respective magnetic fields, wherein the coils are constructed and arranged such that under working conditions, a first homogeneous region (3) can be generated within the envelope defined by the magnet 10 assembly and a second homogeneous region (4) can be generated outside the envelope, the resultant magnetic field in each region being sufficiently homogeneous to enable a NMR process to be performed on an object in the region.

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: A method and apparatus for local grading shielding includes a gradient shield loop having a plurality of arcs positioned adjacent to a superconducting magnet coil. The plurality of arcs magnetically couple with a gradient magnetic field generated by a magnetic field gradient to locally shield the superconducting magnet coil.

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: In an MRI apparatus, an RF coil is provided which can generate or detect a circularly-polarized magnetic field with one feeding port, and which can radiate highly efficient, highly homogeneous electromagnetic waves and detect a highly sensitive, highly homogeneous magnetic resonance signal. For this purpose, the coil has a cylindrical shape, one feeding port which exchanges signals, plural first capacitors disposed at circumferential positions in at least one cross-section effectively orthogonal to the direction of the static magnetic field, and at least one second capacitor. In this RF coil, in which a static magnetic field is applied in essentially an identical direction to the direction of the central axis of the cylindrical shape, a second capacitor having a smaller capacity than the capacity of the first capacitor, is disposed at a position from 22.5° to 67.5° or 202.5° to 247.

Abstract: A mounting device for a local gradient coil unit for mounting same in the examination area of a magnetic resonance unit has one or more guide rails, which are able to be arranged in the examination area, supporting the gradient coil unit, with a locator structure for positioning the gradient coil unit axially on both sides in a mounting position in the examination area, along which guide rail(s) the gradient coil unit slides until it reaches the axial mounting position. One or more fixing elements are fitted on the gradient coil unit for bracing the gradient coil unit in the examination area against the guide rail(s) in the mounting position.

Abstract: A magnet for an NMR analyzer includes a superconductor coil for generating a magnetic field in a magnetic space surrounded by the superconductor coil. The superconductor coil has a shim coil group disposed at least one of inside and outside of the superconducting coil. The superconducting coil provides a first access port for receiving a probe inserted into the magnetic space along a central axis thereof and a second access port having one end for receiving a sample tube containing a sample inserted into the magnetic space in a direction transverse to the central axis of the magnetic space. The second access port is open at an other end thereof.

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 (MRI) system includes a main magnet system for generating a main magnetic field in an examination volume. A gradient coil system is arranged between the main magnet system and the examination volume and includes sub-gradient coils embedded in a binding material which has a glass temperature. A controller controls a temperature of the gradient coil system. A temperature-influencing unit influences the temperature of the gradient coil system on the basis of control signals supplied by the control unit. The control unit and the temperature-influencing unit control the temperature of the binding material of the gradient coil system to a value above the glass temperature during operation of the MRI system.

Abstract: NMR measurements are made with a MWD tool having azimuthal sensitivity. The permanent magnet may be a U-shaped magnet or may have an opposed pair of magnets with axial orientation. The tool is designed for pulsing with short sequences for estimating BVI and CBW and minimizes the effect of tool motion.

Abstract: A superconducting magnet configured for an NMR spectrometer includes a split type superconducting magnet having left solenoid superconducting magnets and right solenoid superconducting magnets with a center space therebetween for receiving a sample tube. A permanent current switch is provided and the left and right solenoid superconducting magnets are arranged symmetrically with respect to a center face of the center space. The left and right solenoid superconducting magnets are constituted by an outermost magnet and a plurality of innermost magnets and are arranged in concentric relation with respect to a vertical axis of the center space. A direction of current in at least one of the plurality of innermost magnets is minus when a direction of current in the outermost magnet is plus.

Abstract: A nuclear magnetic resonance apparatus for generating a homogeneous static magnetic field in the z-direction, comprising a coil/resonator system, a gradient system, and a shielding configuration which is positioned radially between the coil/resonator system and the gradient system, wherein the shielding configuration comprises an electrically conducting layer with a slot, wherein the electrically conducting layer is disposed about the center of the shielding configuration to be axially symmetrical with respect to the z-axis, is characterized in that, in an axial section z1<z<z2 with z2?z1>L, containing at least 90% of the magnetic field energy of the coil/resonator system, the shielding configuration comprises at least one pair of regions which have a cylinder envelope shape, wherein the regions of each pair are each defined by two respectively closed limiting lines circulating about the z-axis, and wherein the two limiting lines of each region have a mutual axial separation a ? z ? ? 2 -

Abstract: A magnetic resonance apparatus comprising a superconducting magnet coil which is disposed in a cryostat, and a refrigerator for cooling the magnet coil, which comprises a compressor for compressing a working gas, and a high-pressure line and a low-pressure line between the compressor and a control valve, which periodically connects the high-pressure line and the low-pressure line to a connecting line from the control valve to a cold head of the refrigerator, thereby generating pressure pulses via the connected working gas, wherein the control valve is mechanically rigidly connected to the cryostat, is characterized in that one pressure reservoir is provided in the high-pressure line and/or in the low pressure line, which is mechanically rigidly connected to the cryostat and which is connected to the compressor via a mechanically flexible line section.

Abstract: An object of the present invention is to intensify the strength of a magnetic field to be applied to a subject. An auxiliary coil is interposed between a body coil incorporated in a magnet assembly included in an MRI apparatus and the subject. When RF pulses are transmitted from the body coil, an induced current flows through the auxiliary coil and generates a magnetic field. The magnetic field excites the subject near the subject.

Abstract: A magnetic resonance imaging (MRI) magnet having a first section and a second section is disclosed. The first section has a first housing, and a first set of magnet coils arranged about a common axis that include coils proximate the common axis. The second section has a second housing, and a second set of magnet coils arranged about the common axis where the coils are radially displaced from the common axis. The second section is connected to but axially displaced a distance “d” from the first section.

Abstract: In order to suppress fringe field due to the magnetic field generated from shield coils along the center axis of main coils and the shield coils that are disposed with their center axes being identical, when reducing fringe field to the outside of a magnet apparatus using the shield coils, the magnet apparatus is configured so that the radii of the main coils are approximately equal to or smaller than the radii of the shield coils, the radii of auxiliary coils are smaller than the radii of the shield coils, the distance between the two main coils is smaller than the distance between the two shield coils, and the distance between the two shield coils is smaller than the distance between the two auxiliary coils.

Abstract: In a magnetic resonance apparatus, the transmission coil for generating the radiofrequency excitation field is stationarily arranged. The geometry of the transmission coil is permanently prescribed. For acquiring the magnetic resonance signal, the reception arrangement includes at least one first local coil. This is secured to a movable carrier, so that it can be placed against the person from a remote position. The carrier is secured in a carrier mount arranged stationarily within the examination volume.

Abstract: Occurrence of noise is to be prevented, and image quality improved. Dynamic dampers which damp vibration attributable to the gradient coil unit are arranged in positions which are extending areas of a gradient coil unit extending to protrude out of an accommodating space, and are different in positions from the accommodating space.

Abstract: In a magnet system utilizing a pair of magnet bodies each having a cylindrical hollow, by effectively utilizing the hollow spaces of the magnet bodies, the ability of adjusting through magnetic shims the magnetic-field homogeneity of a homogeneous static-magnetic-field space region is enhanced. Two magnet bodies each incorporating a group of superconductive coils and each having a cylindrical hollow are arranged opposing each other; the first ring-shaped magnetic shim is arranged in the cylindrical hollow of the one magnet body, concentrically with the first group of superconductive coils; and the second ring-shaped magnetic shim is arranged inside the first ring-shaped magnetic shim, concentrically with the first group of superconductive coils.

Abstract: A controlled power supply (201, 222) drives a magnetic field gradient coil (161) of a magnetic resonance imaging apparatus (10). A gradient amplifier (201) includes a plurality of switching power regulators (50, 52, 54, 56) which are electrically connected in series. A bipolar circuit (70) receives power from the series connected switching power regulators (50, 52, 54, 56) and delivers the power at a selected polarity to the gradient coil (161). A control circuit (221) delivers phase staggered pulse width modulated control signals (A, B, C, D) to the switching power regulators (50, 52, 54, 56).

Abstract: An apparatus for magnetic resonance imaging includes a first magnet for generating a first magnetic field and a second magnet for generating a second magnetic field, dissimilar to the first magnetic field, the second magnet being spaced apart from the first magnet. The apparatus is arranged such that the first and second magnets cooperate to generate a substantially homogeneous magnetic field defining a working region wherein the first and second magnetic fields are arranged asymmetrically with respect to the working region, and wherein at least part of the working region is positioned within the first magnet or between the first and second magnets.

Abstract: A magnetic resonance imaging apparatus and the magnet apparatus thereof comprise plural pairs of magnetic field generation sources, arranged face to face with each other, for forming a magnetic field space 3; and magnetic field homogeneity adjusting apparatuses 17 and 18 for providing homogeneity adjustment of the magnetic field formed in the magnetic field space 3. The magnetic field homogeneity adjusting apparatuses 17 and 18 contain a plurality of tapped holes 24 for installing a magnetic field homogeneity adjusting member 26 of smaller volume in a plate-formed tray made of a non-magnetic substance; and a plurality of mounts 25 for installing the magnetic field homogeneity adjusting member 27 of greater volume, these mounts being formed over the area containing a plurality of through-holes for permitting installation of a magnetic field homogeneity adjusting member 26 of smaller volume, whereby major magnetic field adjusting work can be performed independently of minor magnetic field adjusting work.

Abstract: An open magnetic resonance imaging (MRI) device is provided with at least one main coil for generating a magnetic field for imaging a volume, and at least one shaping coil. The at least one shaping coil is positioned relative to the at least one main coil to shape the magnetic field in the volume.

Abstract: A magnet system of a magnetic resonance apparatus for generating a magnetic field which is homogeneous and temporally highly stable within a volume under investigation and which extends along a z-axis, with a superconducting magnet coil (3) which is disposed in a cryostat (1) and with a periodically operated refrigerator (2) having a magnetic regenerator material which is disposed in a regenerator housing (5) within the cryostat (1) in the stray field of the magnet coil (3), and which is provided with a device (4) for shielding or compensating a magnetic disturbing field in the volume under investigation generated by the periodic operation of the refrigerator (2) due to regenerator magnetization changes is characterized in that the regenerator housing (5) is surrounded by a compensation coil arrangement (4) which can be superconductingly short-circuited and which is made from a plurality of conductor loops (6, 7a, 7b) which are separately short-circuited during measurement to keep a plurality of magnetic flux

Abstract: A vertically-aligned open MRI magnet system includes first and second (i.e., top and bottom) assemblies each having a longitudinally-extending and vertically-aligned axis, a superconductive main coil, and a vacuum enclosure enclosing the main coil. At least one support beam has a first end attached to the first assembly and has a second end attached to the second assembly. A vibration isolation system supports the magnet system.

Abstract: A first room-temperature space is formed penetrating through a cryostat along a center axis of a split-type multi-layer cylindrical superconducting coil system which has a ratio of the maximum empirical magnetic field to the central magnetic field of not larger than 1.3 and is horizontally arranged such that the center axis of the coil is in the horizontal direction, a room-temperature shim coil system is arranged in said first room-temperature space to improve the homogeneity of the magnetic field, a second room-temperature space is formed penetrating through the cryostat and passing through the center of said split gap in the vertical direction, and a sample to be measured and an NMR probe having a solenoid-type probe coil are inserted in said second room-temperature space. Further, the NMR analyzer has a new function constituted by a system for irradiating and detecting the electromagnetic waves having wavelengths of shorter than 0.1 mm.

Abstract: A shielded superconducting MRI magnet system uses a multi-layer shielded coil design. By splitting the magnet coils into a plurality of coil layers, an increased number of degrees of freedom is achieved which, in turn, permits minimization of the overall length of the magnet while nevertheless avoiding excessive magnet field and stress values in the coils. A compact coil system is thereby designed which also satisfies the plurality of MRI requirements with regard to sufficiently large investigational volume, magnet field strength, acceptable homogeneity, and magnet stray field limitation while achieving sufficiently low maximum coil B field strengths and stress values to avoid quenches and maintain the structural integrity of the magnet.

Abstract: The present invention has been made in order to decrease vibrations of gradient-magnetic-field coils in a magnetic apparatus for a magnetic resonance imaging diagnosis system so as to improve the image quality of magnetic resonance images. The magnetic apparatus includes: a superconductive electromagnet having pairs of superconductive coils for generating a uniform static magnetic field region, a pair of vacuum containers each for housing one of the superconductive coils of each of the pairs thereof, and a vacuum container connecting member for connecting the pair of vacuum containers; and a pair of gradient-magnetic-field coils for generating a gradient magnetic field having a gradient in a uniform static magnetic field region.

Abstract: The present invention is intended to provide a magnet apparatus obviating the necessity of shield coils designed to suppress eddy currents. The magnet apparatus has gradient coils disposed in a bore of a cylindrical superconducting magnet, and includes a cylindrical structure that is realized with a combination of tiles made of a high-permeability material and that is interposed between the internal surface of the superconducting magnet and the external surface of the gradient coils. The tiles made of a high-permeability material are laminates made of a high-permeability material. The high-permeability material is a silicon steel plate or an amorphous magnetic material.

Abstract: A magnetic structure enclosing a prismatic cavity of regular polygonal cross-section is presented. The structure contains the field within the volume of the magnet without the need of an external ferromagnetic yoke, which makes it suitable for generating fields of several Tesla. The structures presented are designed to generate uniform fields for NMR studies, especially high intensity fields.

Abstract: An apparatus and method for shimming a magnetic field of a magnet in a volume of interest includes a nonmagnetic holder configured with an array of fluid containing pockets; and a solidified ferromagnetic fluid in each pocket of the array of fluid containing pockets, wherein the solidified ferromagnetic fluid is fabricated from a ferromagnetic fluid, a diluting liquid, a hardener, and an accelerator agent. The ferromagnetic fluid includes a carrier liquid, ferromagnetic particles, and a surfactant.

Abstract: A magnet for an NMR an analyzer includes a superconductor coil which is operated under a permanent current mode so as to generate a magnetic field in a space surrounded by the superconductor coil, and which enables a sample to be inserted into a measurement space in the magnetic space for analization. The superconductor coil includes a first access port for enabling access to the measurement space and a second access port for enabling insertion of the sample into the measurement space in a direction different from a direction of the first access port. An effective diameter of the first access port is larger than an effective diameter of the second access port when the effective diameters of the first and second access ports are defined as a diameter of a cylinder that is insertable into the first and second access ports.

Abstract: A multi-coil NMR probe using nonmagnetic diodes as switches located in close proximity to the radio-frequency circuit of the sample coils within the probe.

Abstract: An actively shielded superconducting magnet coil system (1) for generating a magnetic field in a working volume (6), which is rotationally symmetric about a z-axis, comprising a radially inner main field winding (5) and a radially outer shielding winding (7), and an electrically highly conductive shielding cylinder (radially inner shielding cylinder) (8a/8b) which is disposed radially inside the main field winding (5) or between main field winding (5) and the shielding winding (7) is characterized in that at least one further electrically highly conductive shielding cylinder (9) is disposed radially outside the shielding winding (7). The inventive magnet coil system prevents generation of a fringe field flash in the outer region of the magnet coil system in case of a quench.