Abstract: The invention concerns a method for charging a magnet arrangement (20) comprising a first partial region (21) which can be superconductingly short-circuited via an additional switch (23), and a second partial region (22), wherein the two partial regions (21, 22) generate, in an investigational volume (8), gradients of second order having different signs. A magnetic field dependence B* is measured close to the desired operating state of the magnet arrangement (20) and operating currents are determined for each of the two partial regions (21, 22) at which the overall magnetic field B in the volume (8) under investigation is freed from a magnetic field gradient of second order. These operating currents are set thereby taking into consideration the inductive coupling of the partial regions (21, 22) through initially charging of the overall magnet arrangement (20) and, after closing of the additional switch (23), through continuation of charging only in the second partial region (22).

Abstract: The disclosed apparatus relates to a gradient coil assembly for a magnetic resonance imaging system. The gradient coil assembly comprises: at least two coils. The coils comprise: at least one conductor mechanically bonded via a nonconducting substrate. The bonding surface of the at least one conductor has been subjected to a surface treatment to improve the mechanical bonding properties of the bonding surface. The disclosed apparatus also relates to a magnetic imaging system. The magnetic imaging system comprises: a system controller; a gradient amplifier unit in operable communication with the system controller; a magnetic assembly in operable communication with the gradient amplifier. The magnetic assembly comprises: a gradient coil assembly comprising at least two coils. The coils comprise: at least one conductor mechanically bonded via a nonconducting substrate.

Abstract: Provided is a circular pole piece that contributes to simplification of work and a reduction in costs and that has no gap created among adjoining blocks. A circular pole piece is manufactured by circularly arranging laminate blocks each having numerous hexagonal directional magnetic steel sheet tiles layered. Since heteromorphic soft magnetic material tiles are unnecessary, work can be simplified and the cost of the circular pole piece can be reduced. Moreover, the laminate blocks can be arranged substantially circularly without a gap among adjoining blocks.

Abstract: A magnetic resonance imaging system (10) includes a superconducting magnet (14) that generates a static magnetic field. A gradient coil assembly (50) with an associated patient bore enclosure (18) and a gradient coil (52) that generates a gradient magnetic field in the patient bore (18). A static field-shaping coil (11) resides between the superconducting magnet (14) and the patient bore (18) and supplements the static magnetic field.

Abstract: An open magnetic structure comprising a conical magnetic structure that generates an NMR imaging field around the head of a patient, and a transition magnetic structure including a cylindrical magnet connected to the conical magnetic structures that extends the uniform field generated in the head magnet cavity to or near the shoulders of the patient. The overall geometry is designed to integrate the magnetic structure in a surgical suite with a minimum interference with surgical procedures, which typically involve surgery on the brain of the patient. A method for improving field uniformity by shimming is also included. Advantages include improved field uniformity, and reduced weight and size.

Abstract: A method of operating an imaging system having a main coil and a shield coil electromagnetically coupled to the main coil, wherein the method includes monitoring for an external environmental fluctuation of electromagnetism, and controlling current flow through the main and shield coils based upon the monitoring using a quench heater.

Abstract: A magnetic field generator assembly includes a plurality of magnetic elements configured to collectively generate a magnetic field sufficient for diagnostic data acquisition and a non-magnetizable pane operationally connected to limit separation of one magnetic element from another magnetic element. Accordingly, the multi-element magnetic field generator is efficiently secured against deterioration often associated with prolonged exposure to high order magnetic fields.

Abstract: Nuclear magnetic resonance well logging apparatus and method of use for geophysical examination of a borehole as the borehole is drilled. The apparatus is connected to the drill bit to follow it through the borehole as the borehole is formed. The apparatus comprises a non-magnetic protective collar with lateral protrusions or wings, which provide enhanced abrasion resistance, strength, and rigidity to the probe section. This collar is twisted about its longitudinal axis. The apparatus also comprises one or more permanent magnets within the metal collar and an antenna mounted outside of the collar. Both the magnet and the antenna are twisted about the longitudinal axis of the probe section to produce a generally helical static magnetic field and a radio frequency magnetic field that is substantially orthogonal to the static magnetic field.

Abstract: An open magnetic structure comprising a conical magnetic structure including a hollow conical magnet surrounding and contacting an inner pole piece that generates an NMR imaging field around the head of a patient. The annular surface of contact between the conical magnetic structure and the inner pole piece is configured such that that annular surface of contact is maintained as an equipotential surface to maintain a uniform imaging field. An advantage is to integrate as one-piece the various permanent magnetic sections to greatly simplify fabrication. A method for determining the profile of the annular surface of contact is also included.

Abstract: A magnetic resonance device has a gradient coil system, with an adhesive introduced between the gradient coil system and the rest of the magnetic resonance device to attach the gradient coil system to the rest of the magnetic resonance device.

Abstract: A magnetic resonance imaging system comprises an array of radio frequency (RF) coils for producing controlled RF fields applying excitation signals to a volume of interest and a coil control circuitry configured to excite a single coil from the array of radio frequency coils at a given instant of time, where neighboring coils in the array are deactivated for the given instant of time.

Abstract: The present invention is intended to provide a magnetic pole, a magnet apparatus, and a magnetic resonance imaging apparatus that the magnetic structure of the magnet apparatus for generating a uniform magnetic field is formed in a lower burst mode, and the profitability is increased, and at the same time, the uniformity of the magnetic field is improved. According to the present invention, the magnetic poles arranged opposite to each other across a measuring space have at least one of a plurality of hollows and a single hollow having a shape continuously changing on the section perpendicular to the direction of the magnetic field formed in the measuring space and particularly in order to make the magnetic field uniform, the arrangement of the plurality of hollows and the shape of the single hollow are adjusted. The magnet apparatus and magnetic resonance imaging apparatus of the present invention are structured as mentioned above.

Abstract: An imaging system including at least one pole piece is described. The at least one pole piece includes at least two grain-oriented sheets that are stacked together, where a direction of easy magnetization of a first of the at least two grain-oriented sheets is different than a direction of easy magnetization of a second of the at least two grain-oriented sheets.

Abstract: A matrix coil for generating a variable magnetic field is provided, including a plurality of loops arranged in a series so as to have a substantially common axis and segmented into at least one arc-shaped segment, a variable current source for each of the arc-shaped segments, and a controller. The controller is configured to selectively vary an amount of current provided to each of the arc-shaped segments by the variable current sources so as to achieve a variable base field, one or more variable gradient fields, and one or more variable second order shim fields.

Abstract: It is an object of the present invention to facilitate adjustment of magnetic fields. There is provided a magnetic circuit with opposing permanent magnets, comprising: a pair of permanent magnets opposing each other across a gap, the pair of permanent magnets being magnetized in thickness direction; a yoke magnetically coupled to the permanent magnets, and provided outside of the permanent magnets and the gap; a pair of pole pieces each arranged on a gap side of an opposing surface of each of the permanent magnets and having a peripheral projection in opposing direction; and an adjustment permanent magnet piece having magnetic flux amount of at most 2×10?7 Wb provided so as to magnetically communicate with a magnetic field formed in the gap.

Abstract: A magnetic resonance imaging system comprises a phased array coil assembly and a signal processing circuit. The phased array coil assembly includes a plurality of coils coextensively covering a predetermined area. Each of the plurality of coils comprises a different number of loops over the predetermined area and divides the predetermined area into at least three contiguous regions arranged linearly along the predetermined area. The signal processing circuit is coupled to the phased array coil assembly for receiving a plurality of magnetic resonance signals detected by the plurality of coils. The signal processing circuit is configured to localize the plurality of magnetic resonance signals originating in at least one of the contiguous regions.

Abstract: A gradient coil structure for use in MRI apparatus has a main gradient coil 20 and a shielding coil 21, a portion of the shielding coil being disposed outwardly from the main coil. The coils are configured so that in a peripheral region 25 relative to the image region 22 the are almost coincident and the coils extend forwardly at an angle to the remainder of the main coil so that the main coil appears concave from the imaging region 22. This arrangement provides improved shielding efficiency.

Abstract: A planar MRI system is disclosed. The system has an open magnet configuration that produces a magnetic field having a remote region of substantial magnetic field homogeneity. Spatial encoding gradient coils and a rf coil provide MRI data for image reconstruction. The open magnet configuration has a ferromagnetic core with a substantially planar core surface layer and a longitudinal axis, and a unipolar current wire pair on a side of the ferromagnetic core adjacent the planar core surface layer. The wire pair is separated along the longitudinal axis and extends in a direction substantially perpendicular to the axis and substantially parallel to the planar core surface layer. The current wire pair provides a magnetic field having a maximum between the current wire pair along a direction perpendicular to the planar core surface layer and in the remote region of substantial magnetic field homogeneity.

Abstract: A superconducting magnet, in which a static magnetic filed is generated in a region of interest, i.e. a predetermined volume in which the part under examination has to be placed for imaging characterised in that it is provided with means for generating a uniform annular distribution of electric currents enclosing the polyhedral cavity.

Abstract: A shim adapted for altering a magnetic field of a magnet includes a first material which exhibits an increase in spontaneous magnetization with an increase in temperature for a predetermined temperature range.

Abstract: Briefly in accordance with one aspect, the present technique provides a method for heating a permanent magnet in a magnetic resonance imaging system. The method for heating a permanent magnet includes directly heating a surface of the permanent magnet using a surface heater. The present technique also provides a system for heating a permanent magnet in a magnetic resonance imaging system. The system includes a surface heater configured to directly heat a surface of the permanent magnet.

Abstract: A magnetic resonance has a scanner unit with an examination space for placing at least a region of an examination subject therein, a gradient coil unit movable in a displacement direction at least in the examination space, a component of the scanner unit surrounding the examination space, and at least one pillow that can be arranged between the gradient coil unit and the component and which has an internal pressure that can be controlled for fixing the gradient coil unit relative to the component.

Abstract: The subject invention pertains to a method and apparatus for Nuclear Magnetic Resonance (NMR) imaging. The subject method and apparatus are advantageous with respect to the use of RF coils for receiving signals in NMR scanners. The subject invention can utilize multiple coils to, for example, improve the signal to noise, increase the coverage area, and/or reduce the acquisition time. The use of multiple smaller surface or volume coils to receive NMR signals from the sample can increase the signal to noise ratio compared to a larger coil that has the same field of view and coverage area.

Abstract: The temperature of permanent magnet blocks embedded in several positions in permanent magnets and base yokes will be adjusted by device of a heater to improve the static field uniformity.

Abstract: A coil interface is capable of coupling an array of coils to a magnetic resonance (MR) system. The MR system is equipped with a predetermined number of receivers. The coil interface includes a plurality of input ports, a plurality of output ports, and an interface circuit disposed therebetween. The plurality of input ports is used to couple the interface circuit to the coils of the array. The plurality of output ports is used to couple the interface circuit to the receivers of the MR system. The interface circuit is used to selectively interconnect at least two of the input ports to at least one of the output ports, thereby allowing the array of coils to be selectively operated in any one of a plurality of operational modes.

Abstract: To position and fix the gradient coil assembly in a basic field magnet assembly of a nuclear magnetic resonance tomograph, an annular clamp element is clamped on a surface of the gradient coil assembly between the gradient coil assembly and the basic field magnet assembly. The clamp element has a conical internal surface which is form-fittingly in contact with a similar surface of the gradient coil assembly, so as to provide a self-centering force on the gradient coil assembly and to maintain the gradient coil assembly with an annular gap between the external surface of the gradient coil surface and the interior surface of the basic field magnet assembly.

Abstract: A magnetic resonance imaging apparatus includes a magnetic field generation means for applying gradient magnetic fields and a radio-frequency magnetic field to a patient placed in a static magnetic field in a predetermined pulse sequence; a multiple RF receiving coil comprising at least three RF receiving coils for receiving the nuclear magnetic resonance signals generated from the patient; and an image reconstruction means for reconstructing an image by processing the received nuclear magnetic resonance signals, wherein the image reconstruction means includes a coil selection means for selecting a plurality of RF receiving coil groups that are preset by combining the plurality of RF receiving coils according to imaging conditions, a synthesization means for synthesizing the measured data received by the respective RF receiving coils of each of the plurality of selected RF receiving coil groups, and a calculation means for eliminating aliasing artifacts by executing a matrix calculation as to the synthesized

Abstract: In a super conductive magnet apparatus comprising a super conductive coil, a helium containing volume for containing therein liquid helium to keep a temperature of the super conductive coil low, and a vacuum vessel containing therein the super conductive coil and the helium containing volume, the super conductive magnet apparatus further comprises a support body on which the super conductive coil is arranged, a container cover forming the helium containing volume with the support body in such a manner that a thermal energy is capable of being transmitted between the super conductive coil and the liquid helium, and a connecting member connecting the support body to the vacuum vessel so that the support body is supported through the connecting member on the vacuum vessel.

Abstract: A superconductive magnet device comprises a pair of oppositely disposed superconductive bodies in which annular superconductive coils are accommodated, and fine chip-shaped ferromagnetic shims disposed on a surface of the pair of superconductive magnet bodies so as to improve uniformity of magnetic field in a uniform magnetic field in a uniform magnetic field space generated in the proximity of the center between the superconductive magnet bodies, wherein ring-shaped ferromagnetic shims are disposed concentrically with the center of annular superconductive coils on the surface of the superconductive magnet bodies.

Abstract: A magnetic resonance imaging apparatus generates an MR signal from an object to be examined by applying a gradient field pulse generated by a gradient field coil and a high-frequency magnetic field pulse generated by a high-frequency coil to the object in a static field generated by a static field magnet, and reconstructs an image on the basis of the MR signal. The gradient field coil is housed in a sealed vessel. Numerous techniques are disclosed to reduce adverse effects of vibrations caused by rapidly changing gradient coil currents. By judicious use of non-conducting connection components between gantry components at some joint portions requiring electrical contact and at some other portions not requiring electrical contact, the generation of adverse B waves, and/or induced electron flow in response to physical vibration between joint components can be reduced.

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 magnet device includes two sets of static magnetic field generation sources spaced from each other in the vertical direction such that the uniform magnetic field region (patient space) is between then. Each set has concentric current carrying coils to generate a uniform magnetic field in a first direction (the vertical direction).

Abstract: A local radio-frequency antenna for a magnetic resonance apparatus is fashioned for a region to be imaged in an edge region of and/or outside an imaging volume of the magnetic resonance apparatus, and the radio-frequency antenna has a passive shim device.

Abstract: A method for compensating for magnetic noise fields in spatial volumes includes determining the strength of a magnetic field outside said spatial volume; defining the correlation between the noise field outside the spatial volume and the corresponding noise field inside said spatial volume; generating a magnetic compensation field for neutralizing the noise field in said spatial volume. The method further provides separate detection of noise fields with frequencies in the range of at least two different frequency bands.

Abstract: A product line of MRI systems includes a first MRI system including a first yoke and a plurality of magnet blocks forming a first central assembly disposed on the first yoke. The product line also includes a second MRI system including a second yoke, a plurality of magnet blocks forming a second central assembly disposed on the second yoke and shaped the same as the first central assembly, and a first set of magnet blocks mounted to the second yoke at a periphery of the second central assembly.

Abstract: A gradient coil system for a magnetic resonance apparatus has at least one component of a cooling apparatus, and a latent heat storage apparatus which undergoes a phase transition during operation of the gradient coil system.

Abstract: An open C magnet system for magnetic resonance imaging comprises circular NdFeB poles, a single piece yoke having beveled inside and outside faces between the vertical post section and the horizontal arms of the yoke, a necked-in mid-section of the vertical post, flat Nebdymium (NdFeB) corner plates in face to face relationship with the inside beveled faces between the vertical post and the horizontal arms.

Abstract: A nuclear magnetic resonance (NMR) spectroscopy probe has a sample cell into and out of which a room temperature liquid sample may be directed. The cell is surrounded by a radio frequency coil that is used to perform NMR measurements of the liquid sample, and which is maintained at cryogenic temperatures. The coil is separated from the sample cell by a thermally insulative boundary, such as a vacuum. The sample may enter the cell through an input path, and may exit through an output path. The input path, output path and sample cell may be surrounded by a sheath through which flows room temperature gas. The ends of the sample cell may be tapered to promote thorough flow through the cell, and flow diverters may be included in the sample cell adjacent to the input and output paths to force flow to the outer wall of the sample cell.

Abstract: Remote monitoring of superconducting magnet systems of various types, manufacturers, vintages, and so forth, via a magnet selector interface providing for configuring the monitoring system to the particular magnet system of interest. The technique provides for scalable analogue to digital conversion with integrated excitation circuitry for the input and output of magnet system sensors. Devices, such as remote terminal units and other data-logging technology may be adapted to remotely monitor primary indicators and secondary indicators of magnet system performance and related boil-off of helium. The technique provides earlier warning of impending failures in the magnet system, and thus facilitates predictive maintenance, reduces maintenance costs, reduces MRI downtime, reduces helium loss, and the like.

Abstract: The subject invention pertains to a method and apparatus for Nuclear Magnetic Resonance (NMR) imaging. The subject method and apparatus are advantageous with respect to the use of RF coils for receiving signals in NMR scanners. The subject invention can utilize multiple coils to, for example, improve the signal to noise, increase the coverage area, and/or reduce the acquisition time. The use of multiple smaller surface or volume coils to receive NMR signals from the sample can increase the signal to noise ratio compared to a larger coil that has the same field of view and coverage area.

Abstract: It is an object to provide an MR system and a floor cover capable of being attached and detached by one operator. In the invention, the floor cover covers a front face of a lower part of an open type MR system, and a cradle on which an object is mounted swiftly moves thereon. The floor cover is provided with a slide capable of moving on the lower part.

Abstract: A planar MRI system is disclosed. The system has an open magnet configuration that produces a magnetic field having a remote region of substantial magnetic field homogeneity. Spatial encoding gradient coils and a rf coil provide MRI data for image reconstruction. A first magnet system having a first ferromagnetic core and a first longitudinal axis with a first pair of coils around the first ferromagnetic core and spaced apart along the first longitudinal axis is located orthogonal to and in substantially the same plane as a second magnet system having a second ferromagnetic core and a second longitudinal axis with a second pair of coils around the second ferromagnetic core and spaced apart along the second longitudinal axis. The open magnet configuration preferably has a ferromagnetic core with a substantially planar core surface layer and a longitudinal axis, and a unipolar current wire pair on a side of the ferromagnetic core adjacent the planar core surface layer.

Abstract: Apparatus and methods for performing magnetic resonance imaging. In an embodiment the apparatus comprises a pair of elements spaced apart from each other along a horizontal pole axis so as to define a patient receiving space therebetween. A patient support device is located within the patient receiving space and is operable to accept a patient who enters the patient receiving space in an upright position, e.g., walking. In another embodiment the apparatus comprises a pair of elements supported within a frame. The frame includes upper and lower flux return members that are smaller in a vertical dimension than in a horizontal dimension. In another embodiment, the apparatus comprises a pair of elongated pole members that define an imaging volume having a longer dimension in a vertical direction than in a horizontal direction. An exemplary method includes performing a full body scan of a patient in an upright or sitting position.

Abstract: A method of manufacturing a magnetic resonance imaging (MRI) device is provided including providing at least one magnet positioned between a keeper device and a yoke, the keeper device being positioned at a pole region of the at least one magnet, positioning at least one pole device at the pole region of the at least one magnet, and removing the keeper device from the pole region to allow the at least one pole device to be positioned at the pole region of the at least one magnet.

Abstract: A magnetic resonance imaging apparatus includes a unit (shim coil) that corrects uniformity of a magnetic field, a temperature detecting unit that detects a temperature of a magnet or its surroundings, and a control unit that controls the shim coil based on the detected temperature. The control unit calculates an error component for changing the uniformity of the magnetic field at the detected temperature of the magnet or its surroundings, based on a temperature characteristic of uniformity of the magnetic field calculated in advance. Further, the control unit calculates a shim current that generates a correction magnetic field for canceling the error component, and drives the shim coil based on this shim current.

Abstract: The invention relates to a magnetic resonance imaging apparatus (MRI apparatus) which is provided with an open magnet system and in which there are generated a basic magnetic field (vertical field) which perpendicularly traverses an object to be examined and also an RF field, which MRI apparatus is characterized notably in that coupling effects between a dipole structure (11, 12, 13), formed by the magnet system (10), and an RF conductor structure (20, 21, 22) are eliminated at least to a high degree by shifting or detuning a self-resonant frequency of the dipole structure relative to the MR frequency or by suppressing a self-resonant frequency of the dipole structure.

Abstract: The invention relates to a magnetic resonance imaging (MRI) apparatus (1) comprising a gradient coil assembly (3, 4, 5) for generating gradient magnetic fields in an imaging volume, the gradient coil assembly (3, 4, 5) comprising at least three gradient coils (6) for generating three different gradient magnetic fields. In order to compensate self-induced eddy currents in the gradient coils it is proposed according to the invention to provide a conductive element (71, 72, 73) in close proximity to at least one of the gradient coils (6) in order to compensate self-induced eddy currents in the gradient coil assembly (3, 4, 5). It is thus achieved that undesirable high-order behaviour of the gradient coils is suppressed and that conductive elements (71, 72, 73) are provided in the gradient coil assembly (3, 4, 5) such that undesirable high-order behavior of the gradient coils (3, 4, 5) is suppressed and the nature of the short term self-eddy field becomes similar to that of the gradient coils (3, 4, 5).

Abstract: In this system and method for magnetic resonance imaging, an actively shielded primary coil includes a first and second set of turns each having a prescribed number of turns about an axis, and each being symmetrically positioned radially from the axis and equidistant with respect to a mid plane perpendicular to the axis. A secondary shielding coil includes a third and fourth set of turns each having a prescribed number of turns about the axis and being symmetrically positioned radially from the axis and equidistant with respect to the mid plane. The third set of turns is positioned in close proximity to the first set of turns and outward of the first set of turns. Likewise, the fourth set of turns is positioned in close proximity to the second set of turns and outward of the second set of turns. The first and third sets of turns are in a first prescribed turns ratio and the second and fourth sets of turns are in a second prescribed turns ratio.

Abstract: In a shim tray, a gradient coil system and a magnetic resonance apparatus for the acceptance of the shim tray, the shim tray is sub-divided, in the direction of insertion into the gradient coil system or the magnetic apparatus into at least two sub-trays that can be released from one another.

Abstract: A ferromagnetic frame for supporting a magnet in a magnetic resonance device used for magnetic resonance studies and a method for making the ferromagnetic frame are disclosed. The ferromagnetic frame includes at least one structural element formed of laminated steel layers. The steel layers are relatively lightweight and easily maneuverable compared to solid steel. The method includes laminating the steel layers together to form each of the components of the ferromagnetic frame and then assembling the frame. The ferromagnetic frame of the invention may be incorporated into a full-room magnetic resonance device, in which case the upper support is the ceiling of the room, the lower support is the floor, and the flux return members are the walls. The invention may be incorporated into pre-existing buildings dues to the maneuverability of the layers.