Abstract: The present invention provides a technique for maintaining a function for effectively blocking common mode noise with a simple configuration, even in the case where unbalance occurs in characteristic impedance of a coaxial cable in an MRI apparatus, and improving the performance of an RF coil. In a circuit where a balun is established by parallel connection with the coaxial cable, multiple serial resonance circuits having different resonance frequencies are connected in parallel. A value of each constitutional element of each of the serial resonance circuits is adjusted in such a manner that the frequency for blocking the common mode noise of the entire balun falls into a range between the resonance frequencies of these serial resonance circuits.

Abstract: 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.

Abstract: 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. The coil unit comprises a gradient coil which is disposed along a static magnetic field generating source, and a radio frequency coil which is disposed along the gradient coil in a test region at a position closer to the center of the test region compared with the gradient coil, and a conductor part which is disposed between the gradient coil and the radio frequency coil, and covers periphery of the radio frequency coil. The radio frequency coil comprises a first loop coil and a second loop coil locating in planes substantially perpendicular to direction of the static magnetic field, a plurality of linear conductors connecting the first loop coil and the second loop coil and substantially parallel to the direction of the static magnetic field, and a plurality of first capacitors disposed in the first loop coil and the second loop coil.

Abstract: There is provided a high-frequency coil of an MRI device, which can easily and highly reproducibly reduce electromagnetic coupling between adjacent surface coils among a plurality of surface coils disposed with intervals. An electromagnetic decoupling coil that can generate a magnetic flux for canceling a magnetic flux generated by one of the adjacent surface coils and interlinking with the other surface coil is disposed between the adjacent surface coils. The electromagnetic decoupling coil is provided with a capacitor, and is tuned by means of the capacitor so that the electromagnetic coupling should be minimized in such a range that the resonance frequency thereof should be lower than the resonance frequency of the surface coils.

Abstract: To provide an RF coil of an MRI apparatus and improve the irradiation efficiency and the reception sensitivity of a circular polarized magnetic field with a simple structure. An RF coil has a set of input/output terminals and two loops. The two loops are disposed and capacitors in the loops are adjusted so that the linearly polarized magnetic fields generated and detected by the loops are perpendicular to each other, and the combined magnetic field of the linearly polarized magnetic fields is a circular polarized magnetic field.

Abstract: 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.

Abstract: Provided is an RF coil which can highly efficiently and uniformly irradiate a RF magnetic field having two or more magnetic resonance frequencies close to each other, and receive magnetic resonance signals of two or more magnetic resonance frequencies close to each other with high sensitivity and uniform sensitivity profile in an MRI apparatus. Two or more frequencies to which the coil is tuned are adjusted so as to be between resonance frequencies of series resonant circuits constituting the RF coil.

Abstract: There is provided an RF coil capable of resonating or tuning two frequencies, having uniform spatial sensitivity and having a small spatially occupied volume, especially an RF coil suitable for a high magnetic field MRI apparatus. A coil apparatus is made up of a plurality of linear conductors 200, 201 arranged around a central axis and two ring conductors 202, 203 connected to the respective ends of the plurality of linear conductors 200, 201 and capacitors are inserted in the linear conductors 200, 201 and ring conductors 202, 203. The plurality of linear conductors are made up of conductors 200 located near the central axis and conductors 201 located far from the central axis and the ring conductors 202, 203 have star-like polygonal shape so that the linear conductors are arranged alternately.

Abstract: An RF coil for MR Imaging that can change a resonance frequency easily and instantaneously in response to a nuclide to be imaged without exchange and adjustment and that also causes only small lowering of sensitivity. The RF coil has a sub coil for changing a resonance frequency of the transmitting/receiving RF coil for transmitting and receiving an MR signal between itself and a nuclide that is an object to be imaged. The sub coil is equipped with a switch, and at the time of switching-on, shifts the resonance frequency of the RF coil by changing an inductance value of the RF coil in a noncontact manner using inductance coupling.

Abstract: An RF coil which is resonant and tuned with two different frequencies, has uniform space sensitivity and occupies less space is provided. The coil is, particularly suited to the high magnetic field MRI apparatus. The coil device is equipped with the multiple number of first coils 200 having the first conducting sections 201 and 202 and the second conducting sections 203 and 204, and the second coils 205 and 206 electrically connected with the end of the multiple number of first coils. In the first conducting sections, two conducting parts 201 and 202 are electrically connected via the first condenser 207, while in the second conducting sections, two conducting parts 203 and 204 are electrically connected via the second condenser 208. And the feeding circuit and/or receiving circuit are connected in parallel with the first condenser at one or two positions.

Abstract: An RF coil having at least three different resonance frequencies, wherein one of the resonance frequencies is adjusted to be a frequency fA of a magnetic resonance signal generated by a test subject, and the coil is adjusted so that ratio of difference between the frequency fA and a first frequency fB lower than fA and nearest to fA among the resonance frequencies (fA?fB), and difference between the frequency fA and a second resonance frequency fC higher than fA and nearest to the frequency fA among the resonance frequencies(fC?fA), should be from 0.5 to 2.0. There is provided a technique for receiving magnetic resonance signals always with high detection efficiency by an RF coil of an MRI apparatus even if significant loss is caused in the RF coil, or test subject is changed.

Abstract: To provide an RF coil of an MRI apparatus and improve the irradiation efficiency and the reception sensitivity of a circular polarized magnetic field with a simple structure. An RF coil has a set of input/output terminals and two loops. The two loops are disposed and capacitors in the loops are adjusted so that the linearly polarized magnetic fields generated and detected by the loops are perpendicular to each other, and the combined magnetic field of the linearly polarized magnetic fields is a circular polarized magnetic field.

Abstract: There is provided an RF coil capable of resonating or tuning two frequencies, having uniform spatial sensitivity and having a small spatially occupied volume, especially an RF coil suitable for a high magnetic field MRI apparatus. A coil apparatus is made up of a plurality of linear conductors 200, 201 arranged around a central axis and two ring conductors 202, 203 connected to the respective ends of the plurality of linear conductors 200, 201 and capacitors are inserted in the linear conductors 200, 201 and ring conductors 202, 203. The plurality of linear conductors are made up of conductors 200 located near the central axis and conductors 201 located far from the central axis and the ring conductors 202, 203 have star-like polygonal shape so that the linear conductors are arranged alternately.

Abstract: Provided is an RF coil which can highly efficiently and uniformly irradiate a RF magnetic field having two or more magnetic resonance frequencies close to each other, and receive magnetic resonance signals of two or more magnetic resonance frequencies close to each other with high sensitivity and uniform sensitivity profile in an MRI apparatus. Two or more frequencies to which the coil is tuned are adjusted so as to be between resonance frequencies of series resonant circuits constituting the RF coil.

Abstract: It is intended to provide a Magnetic Resonance Imaging (MRI) phantom for 1H/19F signal detection that permits the stable and uniform dispersion of a vesicle and to accomplish the adjustment of a measurement parameter for a 1H/19F signal and performance confirmation by use of the phantom. The present invention provides an MRI phantom having a gel comprising a vesicle comprising at least one of a perfluorocarbon and a superparamagnetic iron oxide particle and an MRI system having the phantom.

Abstract: A magnetic resonance imaging (MRI) apparatus for high-speed and high-accuracy detection of cell positions labeled with magnetic nanoparticles. A transmitter coil is controlled to generate amplitude-modulated burst RF pulses as excitation RF pulses whose amplitude is modulated by a function that repeatedly inverts the polarity of multiple high-frequency magnetic field sub-pulses separated time-wise and changes the amplitude at each polarity inversion, moreover the time interval of the amplitude-modulated burst RF pulse is set to effectively 1/(2×a first frequency), and the transmitter coil controlled so the carrier frequency of the amplitude-modulated burst RF pulse is set to a second frequency shifted substantially from the first frequency of the magnetic resonance frequency of the proton at the magnetic field strength in the MRI apparatus.

Abstract: An RF coil which is resonant and tuned with two different frequencies, has uniform space sensitivity and occupies less space is provided. The coil is, particularly suited to the high magnetic field MRI apparatus. The coil device is equipped with the multiple number of first coils 200 having the first conducting sections 201 and 202 and the second conducting sections 203 and 204, and the second coils 205 and 206 electrically connected with the end of the multiple number of first coils. In the first conducting sections, two conducting parts 201 and 202 are electrically connected via the first condenser 207, while in the second conducting sections, two conducting parts 203 and 204 are electrically connected via the second condenser 208. And the feeding circuit and/or receiving circuit are connected in parallel with the first condenser at one or two positions.

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: An RF coil has at least one conductor loop and a parallel circuit provided with a first branch and a second branch is installed. The first branch has a first capacitor and the second branch has a third capacitor and a first parallel resonance circuit configured by a second capacitor and a first inductor. The first capacitor has capacity to allow the RF coil to resonate at the time of transmission/reception of the first resonance frequency signal corresponding to an element with a higher magnetic resonance frequency, and capacity of the second capacitor and a value of the first inductor are determined as an accumulated value thereof based on the first resonance frequency. The third capacitor has capacity to allow the RF coil to resonate at the time of transmission/reception of the second resonance frequency signal corresponding to an element with a lower magnetic resonance frequency.

Abstract: A superconductor signal amplifier which receives an extremely small high-frequency signal having a frequency of tens of GHz generated in a superconductive circuit, amplifies the voltage of the high-frequency signal without a decrease in frequency, and outputs the thus amplified high-frequency signal from the superconductive circuit. At an output part of a single flux quantum circuit using a flux quantum as a binary information carrier, there are provided a superconductive junction line for flux quantum transmission and a splitter for simultaneously producing two flux quanta from a flux quantum. According to the number of plural series-connected SQUIDs, a plurality of flux quantum signals are generated and input to the plural series-connected SQUIDs so that the SQUIDs are simultaneously switched to a voltage state. In each SQUID pair comprising two SQUIDs, a part of an inductor is shared by the two SQUIDs for reduction in inductance, thereby increasing an output voltage of the series-connected SQUIDs.