Patent application number | Description | Published |
20090189721 | SUPERCONDUCTING MAGNET AND MAGNETIC RESONANCE IMAGING APPARATUS - In a superconducting magnet, including a vacuum vessel, a coil vessel inside the vacuum vessel, and a superconducting coil inside the coil vessel for generating a magnetic field, has a magnetic member, disposed inside the vacuum vessel, supported with thermal insulation, for compensating the magnetic field; a heat exchange device disposed outside the vacuum vessel for supplying to or absorbing heat from the vacuum vessel; and thermal conducting members thermally connecting the heat exchange device via the vacuum vessel to the magnetic member. An MRI including the superconducting magnet is also disclosed. | 07-30-2009 |
20090201020 | MAGNETIC RESONANCE APPARATUS UTILIZING TIME-VARYING RATE OF MAGNETIC RESONANT FREQUENCY - The present invention provides a magnetic resonance imaging system capable of performing spectrum measurement even when a magnetic resonant frequency changes during MRS measurement. A time-varying rate of a water magnetic resonant frequency is measured in advance before the MRS measurement. The amount of change in water magnetic resonant frequency during the MRS measurement is predicted from the measured time-varying rate. With the predicted value as the reference, a transmission frequency of an RF magnetic field irradiated in a signal suppression pulse sequence, a transmission frequency of an RF magnetic field for excitation and inversion and a received frequency at the detection of a magnetic resonance signal in a sequence of the MRS measurement are respectively set. A high-precision spectrum measurement is hence enabled. | 08-13-2009 |
20100033177 | Inspection Apparatus using Magnetic Resonance and Nuclear Magnetic Resonance Signal Receiver Coil - An MRI apparatus capable of selecting an optional direction as a phase encoding direction and achieving a preferable S/N, when an imaging time shortening technique is applied. A receiver coil, used as a receiver coil of a vertical magnetic field MRI apparatus, is a combination of a first coil (solenoid coil) forming a current loop around the outer circumference of a test object, second coils forming even-numbered current loops, and third coils forming odd-numbered current loops, in the direction intersecting the plane of the current loop of the first coil. The second coil and the third coil are arranged in such a manner that, as for the current loops in the array direction thereof, a position where a sensitivity of one coil is minimized approximately coincides with a position where the sensitivity of the other coil is maximized, whereby electromagnetic coupling is suppressed. | 02-11-2010 |
20100253347 | ANTENNA SYSTEM AND MAGNETIC RESONANCE IMAGING APPARATUS - An RF coil is provided with a hollow-shaped outer conductive element and strip-shaped conductive elements disposed along the outer conductive element in the axial direction. The strip-shaped conductive elements are disposed with uneven intervals to secure an internal space at a position where the strip-shaped conductive elements are not disposed. In order to obtain uniform sensitivity at the center section of the RF coil, the strip-shaped conductive elements and the outer conductive element are electrically connected via capacitors of which capacitances are adjusted so that a magnetic field component perpendicular to the center axis should be generated at a desired resonance frequency, and the strip-shaped conductive elements are axisymmetrically disposed with respect to the center axis of the outer conductive element. As a result, a comfortable examination space in a tunnel type MRI apparatus is achieved without increasing the manufacturing cost of the MRI apparatus. | 10-07-2010 |
20110112393 | MAGNETIC RESONANCE IMAGING DEVICE - In the diffusion-weighted imaging, amounts of distortion and amounts of phase offset of k-space data due to a temporally changing magnetic field error induced by eddy currents and vibrations associated with application of a diffusion-weighted gradient magnetic field pulse are corrected with good precision to improve image quality. Characteristic data for correcting distortion of k-space data are calculated for every position in the slice direction as peak shifts of projections observed between the cases of applying and not applying an MPG pulse. As the characteristic data, amounts of distortion in the read-out direction and the phase encoding direction and phase offset amounts in a slice plane are calculated. | 05-12-2011 |
20110175616 | Nuclear Magnetic Resonance Imaging System and Coil Unit - There is provided a coil unit having a large region of homogeneous sensitivity for the axial direction even with a shortened rung length of birdcage type RF coil. | 07-21-2011 |
20120176137 | GRADIENT MAGNETIC FIELD COIL AND MAGNETIC RESONANCE IMAGING DEVICE - In the magnetic resonance imaging device, the distance between the first and second coils is different in the circumferential direction and has a first region (A | 07-12-2012 |
20120262173 | HIGH-FREQUENCY COIL UNIT AND MAGNETIC RESONANCE IMAGING DEVICE - There is provided a technique for securing a large examination space in a tunnel type MRI device without inviting increase of manufacturing cost and without significantly reducing irradiation efficiency or uniformity of the irradiation intensity distribution in an imaging region. Between rungs of a partially cylindrical RF coil, which coil corresponds to a cylindrical RF coil of which part is removed, there are disposed half-loops generating magnetic fields, which are synthesized with magnetic fields generated by loops constituted by adjacent rungs of the partially cylindrical RF coil and rings connecting the rungs to generate a circularly polarized or elliptically polarized magnetic field. Further, high-frequency signals of the same reference frequency having a desired amplitude ratio and phase difference are supplied to the partially cylindrical RF coils and half-loops. | 10-18-2012 |
20120299594 | ANTENNA DEVICE - There is provided a technique for securing a comfortable examination space in a tunnel type MRI apparatus without increasing the manufacturing cost of the MRI apparatus and sacrificing performance thereof. In an RF coil provided with a hollow-shaped outer conductive element and a strip-shaped conductive element disposed along the outer conductive element in the axial direction, meander lines constituting the strip-shaped conductive element are disposed at uneven distances from the outer conductive element to secure an internal space. In order to obtain uniform sensitivity at the center of the RF coil, the strip-shaped conductive element is constituted with N of connected meander lines, and length of the strip-shaped conductive element is adjusted so that, in the strip-shaped conductive element resonating at resonance frequency of the antenna, nodes are formed in a number of (M+1)×N−1, wherein M is 0 or a natural number of 1 or larger. | 11-29-2012 |
20130119991 | HIGH-FREQUENCY COIL AND MAGNETIC RESONANCE IMAGING DEVICE EMPLOYING SAME - A technique is provided to reserve large examination space in the tunnel type MRI apparatus, without increasing production cost nor reducing significantly irradiation efficiency and homogeneity in an irradiation distribution within an imaging region. The present invention provides an RF coil unit in which four partial cylindrical coils are placed with a gap therebetween in the circumferential direction inside a cylindrical RF shield, in such a manner that two pairs of the partial cylindrical coils are opposed to each other, and magnetic fields produced by the individual partial cylindrical coils are combined, thereby producing a circularly polarized wave field or an elliptically polarized wave field. The partial cylindrical coil is provided with a partial cylindrical conductor, multiple first conductors substantially parallel with the central axis of the RF shield, multiple capacitors connecting both ends of the first conductors with the partial cylindrical conductor, and a second conductor adjacent to at least one of the ends of the first conductor. The partial cylindrical coils are respectively provided with high frequency signals having a desired amplitude ratio and phase difference, while a reference frequency thereof being identical. | 05-16-2013 |
20130221968 | ANTENNA DEVICE AND MAGNETIC RESONANCE IMAGING DEVICE - There is provided a technique for suppressing increase of SAR without sacrificing sensitivity in RF coils used in MRI apparatuses. The present invention provides an antenna device comprising a sheet-shaped conductor and a ribbon-shaped conductor disposed on the subject side with respect to the sheet-shaped conductor with a predetermined distance from the sheet-shaped conductor. The ribbon-shaped conductor has a meandering shape, and is adjusted so as to resonate at transmission and reception frequencies, and it is constituted so that distance to the sheet-shaped conductor becomes smaller at both end part thereof along the static magnetic field direction compared with the distance to the sheet-shaped conductor at the center thereof. Moreover, the ribbon-shaped conductor is constituted so as to have a smaller width, as the distance to the sheet-shaped conductor becomes smaller. | 08-29-2013 |
20130335088 | GRADIENT COIL DEVICE AND MAGNETIC RESONANCE IMAGING DEVICE - A gradient coil device includes a major axis gradient coil, having an ellipse in a cross section generating a gradient magnetic field inclined in a major axis direction of the ellipse at a magnetic field space; and a minor axis gradient coil, having an ellipse in a cross section generating a gradient magnetic field inclined in a minor axis direction of the ellipse at the magnetic field space. A length of the minor axis field coil in the center axis direction is shorter than a length of the major axis gradient coil in the center axis direction. A maximum value of a residual magnetic field generated by the minor axis gradient coil at a space outside the magnetic field space is equal to or smaller than a maximum value of a residual magnetic field generated by the major axis gradient coil at a space outside the magnetic field space. | 12-19-2013 |