Hitachi Medical Corporation

Hitachi, Ltd.

Kyocera Corporation

Masayoshi Dohata

Hisaaki Ochi

Yoshihisa Soutome

Yoshitaka Bito

Hideta Habara

Hiroyuki Takeuchi

Tetsuhiko Takahashi

Yoshiyuki Miyamoto

Shizuka Nagai

Daisuke Yokoyama

Takayuki Abe

Kosuke Ito

Yukio Kaneko

Yoshimi Kasai

Yosuke Otake

Kohjiro Iwasawa

Kazuhiro Iwabuchi

Takahide Shimoda

Takeshi Taniguchi

Shinichiro Suzuki

A high-frequency array coil for an MRI apparatus includes: a plurality of coil units each of which includes a plurality of RF reception coils including a conductor loop and adjusted to receive a magnetic resonance signal; an extension conductor which includes a part of each conductor loop of each RF reception coil of the plurality of coil units and a conductor connecting the parts; and an extension conductor control circuit which adjusts a reception frequency of the extension conductor. The extension conductor is disposed so as to be wound in a spiral shape when the extension conductor is disposed on a subject and a direction of a magnetic field to be detected intersects a direction of a magnetic field detected by the RF reception coil constituting the coil unit. Accordingly, the detection efficiency of an RF coil can be increased and an image with a high SNR can be obtained.

Array coil and magnetic resonance imaging apparatus

In a magnetic resonance imaging device provided with a deformable RF coil permanently mounted on a patient table, the RF coil can constantly maintain a matching state and a tuned state in a state of being flat on a top plate and in a state of being wound around a test object. Coil-side connectors-and-provided in a deformable RF coilform a detector in cooperation with any one of fixture-side connectors-to-, in which the detector detects a fitted state therebetween. A tuning circuit and a matching circuit of coil elements of the RF coilare switched by an output of the detector to change tuning and matching parameters, and to maintain a matching state and a tuned state with respect to a state change indicating that the RF coilis in a wound state.

Magnetic resonance imaging device and RF coil assembly with matching switch circuit and tuning switch circuit

A lower cost MRI device with a portable table detachable from the gantry is provided along with a lower cost table equipped with an easy-to-use and easy-to-install RF coil system able to perform high-resolution head and neck imaging and high-speed whole body imaging in both head-first and feet-first modes. This magnetic resonance imaging device has a portable table detachable from the gantry, and the portable table has a docking connector that can be connected to the gantry and a ceiling panel on which an RF coil can be installed to receive nuclear magnetic resonance signals generated by the examinee and to irradiate the examinee with a high-frequency magnetic field. The RF coil is divided into two or more RF coil units, the ceiling panel has a plurality of ceiling panel connectors enabling each RF coil unit to be connected, and each RF coil unit has a connector. Each RF coil unit is arranged in overlapping fashion on the ceiling plate and the ceiling panel connectors and coil connectors are connected without having to establish an electrical connection between RF coil units.

Magnetic resonance imaging device and RF coil

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.

Antenna device and magnetic resonance imaging device for suppressing absorption rate of irradiated waves

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)&#xd7;N&#x2212;1, wherein M is 0 or a natural number of 1 or larger.

Magnetic resonance examination apparatus and antenna device

Manufacture cost and maintenance cost of RF coils of MRI devices are reduced without any limitation concerning size of the coils. By constituting an antenna device for magnetic resonance imaging devices with a cylindrical outer conductor, a looped ribbon-shaped conductor disposed inside the cylindrical outer conductor along the cylindrical surface, and a feed point for transmission and/or reception between the cylindrical conductor and the ribbon-shaped conductor, and disposing the ribbon-shaped conductor so that length thereof can be readily adjusted, there is provided an antenna device for magnetic resonance imaging devices that generates a magnetic field component perpendicular to the central axis of the cylinder at a desired resonance frequency and shows sensitivity without using capacitors and without being imposed any limitation concerning size in the diametral direction of the cylinder.

Antenna device and magnetic resonance imaging device

A magnetic resonance imaging apparatus is provided, characterized by: one pair of static magnetic field generating means disposed sandwiching a space in which a test object is placed; magnetic field generating means configured to apply a high-frequency magnetic field and a gradient magnetic field to the test object placed in the static magnetic field; and receiving means configured to receive a nuclear magnetic resonance signal generated from the test object, and characterized in that: the receiving means includes a receiving coil having a predetermined coil pattern and capable of being shaped into a cylinder; the receiving coil includes flexible parts and rigid parts alternately disposed along the circumference direction when shaped into the cylinder; and the flexible parts include a flexible substrate on which a portion of the predetermined coil pattern is mounted and a air-bubbles-containing resin section for covering the both surfaces of the flexible substrate.

Magnetic resonance imaging apparatus, receiving coil and method of manufacturing the coil

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.

Antenna system and magnetic resonance imaging apparatus

A magnetic resonance imaging apparatus comprises: static magnetic field generation means which generates a static magnetic field in an imaging space where an object to be examined is placed; gradient magnetic field generation means which generates a gradient magnetic field in the imaging space; high-frequency magnetic field generation means which generates a high-frequency magnetic field in the imaging space; calculation means which calculates an amount of the electromagnetic wave absorbed by the object when the high-frequency magnetic field is irradiated to the object; and a measurement means which measures a characteristic of the high-frequency magnetic field generation means. The calculation means calculates the amount of the electromagnetic wave absorbed by the object according to the characteristic of the high-frequency magnetic field generation means measured by the measurement means.

Magnetic resonance imaging apparatus

The present invention provides a vertical magnetic field MRI apparatus which is capable of speeding up imaging for taking an image of any cross section of a wide area such as a total body, while suppressing increase of the number of channels and maintaining high sensitivity in a deep portion of a subject. A receiver coil unitincorporates a bed coil unitwhose longitudinal direction agrees with a body axis direction of the test object, and an upper coil unitwhich is detachably mounted on the bed coil unit. The bed coil unitis provided with a carrying surfacefor placing the test objectthereon and multiple lower sub-coils arranged in a lower part of the carrying surface, and the upper coil unitis provided with multiple upper sub-coils which are connected to the lower sub-coils. The upper sub-coils are separated into two parts; one arranged in a flexible inner support-covering the installation surfaceand another arranged in a flexible outer support-covering the external side of the inner support-. The upper sub-coils and the lower sub-coils are connected by mounting the upper coil uniton the bed coil unit, thereby forming the multiple types of sub-coils.

This invention provides a receiving coil that allows a high-quality image of high depth sensitivity to be obtained during vertical magnetic field MRI without limiting selection of a cross section to be imaged and of a phase-encoding axis. A subject's field of view is broadened without deterioration of the coil characteristics. Two orthogonal solenoid coils (-and-) and sub-coils (--, and-) whose sensitivity distributions each become an odd function in an x-direction, a y-direction, and a z-direction, respectively, with respect to the origin of the sensitivity distribution of each of the solenoid coils are used as multiple sub-coils to construct the receiving coil. This receiving coil is suitable for a high-speed imaging method in which an image is acquired using reduced phase encoding and the image is reconstructed using image folding. In addition, the subject's field of view can be broadened by arranging conductors of the coil appropriately.

Magnetic resonance imaging apparatus and RF coil for magnetic resonance imaging apparatus

A vertical magnetic field type MRI apparatus is capable of high-speed-imaging a large cross section such as a whole human body while suppressing an increase in the number of channels and maintaining sensitivity to a deep portion of a subject to be high. A receiving coil is composed of a plurality of sub coils. A first sub coil (-) of the receiving coil is arranged in a first plane () including an axis substantially parallel to the direction of a static magnetic field and forms a first current loop around the surface of the subject. A second sub coil (-) of the receiving coil is constituted by a pair of conductor loops (--) that sandwich the subject in the vicinities of the surface of the subject and are arranged substantially symmetrically each other. The conductor loops have respective cross points (--). The conductor loops are arranged with the first sub coil to ensure that the cross points are located in the first plane in which the current loop of the first sub coil is provided. An electromagnetic coupling between the first and second sub coils is not generated. The second sub coil exhibits a sensitivity distribution symmetrical to the direction of the static magnetic field. The first and second sub coils are arranged as a basic configuration and combined with each other to ensure that an electromagnetic coupling with another sub coil that exhibits a sensitivity distribution symmetrical to x and y directions is suppressed.

Radio frequency coil for magnetic resonance imaging apparatus

An object is to provide a portable radio communication apparatus which allows a user to easily view displayed contents when the apparatus is folded even in the nighttime or in a dark place, and which can extend the battery life. A second caseis connected to a first caseso as to be in open and closed positions with respect to the first case. A main display sectionwhich is exposed when the second caseis in the open position, a sub-display sectionwhich is exposed whether the second caseis in the open or closed position, a main illuminating deviceA which illuminates the main display section, and a sub-illuminating deviceB which illuminates the sub-display sectionare provided. A driverwhich selects a line to supply electric power for illumination to the main illuminating deviceA or the sub-illuminating deviceB, and a detecting switchwhich detects whether the second caseis in the open or closed position, are also provided. A control sectionis also provided which controls the driver, with reference to the detected result, to supply electric power to the main illuminating deviceA when the second caseis in the open position, and to supply electric power to the sub-illuminating deviceB when the second caseis in the closed position.

Growing community of inventors

Yokohama, Japan

Masayoshi Dohata