WO2012165295A1 - Circuit à résonance - Google Patents

Circuit à résonance Download PDF

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Publication number
WO2012165295A1
WO2012165295A1 PCT/JP2012/063325 JP2012063325W WO2012165295A1 WO 2012165295 A1 WO2012165295 A1 WO 2012165295A1 JP 2012063325 W JP2012063325 W JP 2012063325W WO 2012165295 A1 WO2012165295 A1 WO 2012165295A1
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WO
WIPO (PCT)
Prior art keywords
coil
resonance circuit
circuit
resonance
capacitor
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Application number
PCT/JP2012/063325
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English (en)
Japanese (ja)
Inventor
芳親 吉岡
大松 朱
Original Assignee
国立大学法人大阪大学
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Publication of WO2012165295A1 publication Critical patent/WO2012165295A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
    • G01R33/34—Constructional details, e.g. resonators, specially adapted to MR
    • G01R33/341—Constructional details, e.g. resonators, specially adapted to MR comprising surface coils
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
    • G01R33/36—Electrical details, e.g. matching or coupling of the coil to the receiver
    • G01R33/3628—Tuning/matching of the transmit/receive coil

Definitions

  • the present invention relates to a resonance circuit, and more particularly to a resonance circuit used in a magnetic resonance apparatus.
  • the magnetic resonance method is non-invasive and can examine the structure and state of an object (sample), and has recently been suitably used not only for research but also for diagnosis.
  • magnetic resonance imaging Magnetic Resonance Imaging: MRI
  • nuclear magnetic resonance Nuclear Magnetic Resonance: NMR
  • a strong magnetic field is applied to a sample, and a precession around the direction of the static magnetic field is induced in the magnetic moment of the nucleus with a nuclear spin in the sample, and orthogonal to the direction of the static magnetic field.
  • a high frequency magnetic field is applied to excite the precession of the nuclear magnetic moment, and then the electromagnetic wave emitted when the precession of the nuclear magnetic moment returns from the excited state to the ground state is sampled. Observe as a unique high frequency magnetic field.
  • the MRI apparatus collects data on the spin density distribution of the nuclei of hydrogen atoms and the relaxation time distribution of magnetization at the examination site of the sample using the magnetic resonance phenomenon, and displays a tomographic image of the examination site.
  • Patent Document 1 describes a magnetic resonance apparatus that transmits and receives electromagnetic waves using an LC circuit.
  • the coil and the capacitor of the LC circuit are configured to resonate with an electromagnetic wave having a predetermined frequency, and the resonance frequency is expressed as 1 / (2 ⁇ ⁇ ⁇ (LC)).
  • signal sensitivity in a magnetic resonance apparatus is not so high, and improvement in sensitivity is desired.
  • the integration time can be reduced to 1 ⁇ 4, and when the integration times are equal, the resolution can be improved.
  • a magnetic resonance apparatus in which the static magnetic field used for magnetic resonance is increased is underway.
  • a magnetic resonance apparatus that applies a static magnetic field exceeding a magnetic flux density of 7 T (300 MHz) has been developed for humans, and for small animals, a magnetic field that applies a static magnetic field of a magnetic flux density of 11.7 T (500 MHz) or higher has been developed.
  • a resonance device has been developed.
  • the inductance of the coil can be increased by increasing the number of turns of the coil and / or the diameter of the coil.
  • the LC circuit may not be able to transmit and / or receive electromagnetic waves of a predetermined frequency.
  • the static magnetic field in the magnetic resonance apparatus is relatively large, it is difficult to increase the number of turns of the coil and / or the diameter of the coil.
  • the frequency of the electromagnetic wave that resonates with the nuclear moment of hydrogen atoms is 500 MHz or more.
  • a 1-turn or 2-turn coil having an inner diameter of about 10 mm is used.
  • the present invention has been made in view of the above problems, and an object thereof is to provide a resonance circuit with improved sensitivity in magnetic resonance.
  • a resonance circuit according to the present invention is a resonance circuit used in a magnetic resonance apparatus, and the resonance circuit performs at least one of transmission of an electromagnetic wave having a predetermined frequency to a sample and reception of the electromagnetic wave from a sample
  • the resonant circuit includes a coil and an LC circuit having at least one capacitor electrically connected to the coil, and a transmission line electrically connected to the LC circuit, and the coil of the LC circuit and The capacitor is configured to resonate at a frequency different from the predetermined frequency, and the LC circuit and the transmission line are configured to resonate at the predetermined frequency.
  • the coil and the capacitor of the LC circuit are configured to resonate at a frequency lower than the predetermined frequency.
  • the transmission line transmits the electromagnetic wave in a TEM mode.
  • the transmission line includes the first conductor and the second conductor electrically connected to the LC circuit, and the first conductor and the second conductor correspond to the predetermined frequency.
  • the first conducting wire and the second conducting wire are not short-circuited with each other.
  • the transmission line includes a coaxial cable.
  • the transmission line is configured such that impedance is substantially zero when viewed from the LC circuit.
  • the coil has a first wiring and a second wiring
  • the at least one capacitor has a capacitor connected to the first wiring and the second wiring.
  • the coil has a plurality of turns.
  • the plurality of turns have different diameters.
  • the coil has three or more turns.
  • the coil has an inner diameter of 10 mm or more.
  • the predetermined frequency is 500 MHz or more.
  • the coil has a shape that matches the sample.
  • a resonance circuit according to the present invention is a resonance circuit used in a magnetic resonance apparatus, and the resonance circuit performs at least one of transmission of an electromagnetic wave having a predetermined frequency to a sample and reception of the electromagnetic wave from a sample,
  • the predetermined frequency is 500 MHz or more
  • the resonance circuit has a coil having three or more turns, and the inner diameter of the coil is 10 mm or more.
  • a resonance circuit with improved sensitivity in magnetic resonance can be provided.
  • FIG. 1 is a schematic diagram of an embodiment of a resonant circuit according to the present invention. It is a schematic diagram of the magnetic resonance apparatus provided with the resonance circuit shown in FIG. 1 is a schematic diagram of an embodiment of a resonant circuit according to the present invention. 1 is a schematic diagram of an embodiment of a resonant circuit according to the present invention. It is a schematic diagram of the resonant circuit of this embodiment. It is a schematic diagram of the resonant circuit of this embodiment. It is a schematic diagram of the resonant circuit of this embodiment. It is a schematic diagram of the resonant circuit of this embodiment. It is a schematic diagram of the resonant circuit of this embodiment.
  • (A) is the schematic diagram which has arrange
  • (b) is a figure which shows the image obtained by (a).
  • (A) to (f) are images obtained by using the resonance circuit of the comparative example.
  • (A) to (f) are images obtained by using the resonance circuit of the comparative example.
  • (A) And (b) is the graph which showed distribution in the image of FIG.13 (f).
  • (A) is an image obtained using the resonance circuit of the comparative example, and (b) is an image obtained using the resonance circuit shown in FIG. (A) And (b) is a schematic diagram of the coil in the resonance circuit of this embodiment.
  • (A) is an image obtained using the resonance circuit of the comparative example, and (b) is an image obtained using the resonance circuit shown in FIG. (A), (b) and (c) are images obtained using the resonance circuit of the comparative example.
  • (A), (b), and (c) are images obtained using the resonance circuit shown in FIG. It is the image obtained using the resonance circuit of this embodiment.
  • FIG. 1 shows a schematic diagram of a resonance circuit 10 of the present embodiment.
  • the resonance circuit 10 is used in a magnetic resonance apparatus.
  • the resonant circuit 10 performs at least one of transmission of an electromagnetic wave (high frequency) having a predetermined frequency to the sample and reception of the electromagnetic wave from the sample.
  • the frequency of the electromagnetic wave resonating in the resonance circuit 10 is set according to the static magnetic field in the magnetic resonance apparatus.
  • the predetermined frequency described above may be referred to as the resonance frequency of the resonance circuit.
  • the resonance circuit 10 includes an LC circuit 20 and a transmission line 30 electrically connected to the LC circuit 20.
  • the LC circuit 20 includes a coil 22 and a capacitor 24 that is electrically connected to the coil 22.
  • the coil 22 has one or more turns.
  • the LC circuit 20 may have a plurality of capacitors 24.
  • the capacitor 24 may be connected to the coil 22 in series, or may be connected to the coil 22 in parallel. A plurality of capacitors connected in series and in parallel to the coil 22 may be used as the capacitor 24.
  • the transmission line 30 transmits electromagnetic waves in a TEM (Transverse Electromagnetic) mode.
  • TEM Transverse Electromagnetic
  • the transmission line 30 for example, a coaxial cable, a Lecher line, or a strip line is used.
  • the transmission line 30 is configured such that the impedance is substantially zero when viewed from the LC circuit 20.
  • the coil 22 and the capacitor 24 of the LC circuit 20 have a resonance frequency different from the resonance frequency of the resonance circuit 10, but the LC circuit 20 and the transmission line 30 are used simultaneously. And is configured to resonate at a predetermined resonance frequency. For this reason, even if the configuration of the LC circuit 20 is changed, the resonance circuit 10 can transmit and / or receive an electromagnetic wave having a resonance frequency. For example, when the number of turns of the coil 22 of the LC circuit 20 is increased, the reception sensitivity of the electromagnetic wave can be improved. On the other hand, the frequency at which the LC circuit 20 resonates may be reduced. By providing this, a decrease in the resonance frequency in the resonance circuit 10 can be suppressed.
  • the LC circuit 20 and the transmission line 30 are configured so that the impedance of the resonance circuit 10 is minimized with respect to a predetermined frequency.
  • the resonance frequency of the LC circuit 20 itself may be lower than a predetermined frequency, and the resonance frequency of the transmission line 30 itself may be higher than the predetermined frequency.
  • the resonance frequency of the LC circuit 20 itself may be higher than a predetermined frequency, and the resonance frequency of the transmission line 30 itself may be lower than the predetermined frequency.
  • the LC circuit 20 may be connected in parallel with the transmission line 30.
  • FIG. 2 shows a schematic diagram of the magnetic resonance apparatus 100 including the resonance circuit 10.
  • the magnetic resonance apparatus 100 includes a resonance circuit 10, a static magnetic field generation unit 110 that applies a static magnetic field, and a gradient magnetic field generation unit 120 that applies a gradient magnetic field.
  • the static magnetic field generation unit 110 is formed of a coil and is connected to a static magnetic field generation power source 112.
  • the gradient magnetic field generation unit 120 is formed of a coil and is connected to the gradient magnetic field generation power source 122.
  • each of the static magnetic field generation unit 110 and the gradient magnetic field generation unit 120 is provided in a cylindrical shape, and the sample is disposed at the center portion thereof.
  • the coil 22 of the resonance circuit 10 is used as a surface coil of the magnetic resonance apparatus 100.
  • the resonant circuit 10 transmits electromagnetic waves to the sample and receives electromagnetic waves from the sample, but the resonant circuit 10 performs one of transmission of electromagnetic waves to the sample and reception of electromagnetic waves from the sample, and the other. May be performed by another circuit.
  • a high-power electromagnetic wave may be irradiated using a large-diameter transmission circuit provided outside, and a high frequency may be locally received using the resonance circuit 10 as a reception circuit.
  • the magnetic moment of a hydrogen nucleus that receives electromagnetic energy is 42.6 MHz / T.
  • the frequency of electromagnetic waves transmitted and received from hydrogen atoms is 64 MHz.
  • the frequency of the electromagnetic wave is 128 MHz.
  • the frequency of the electromagnetic wave is 500 MHz.
  • FIG. 3 shows a schematic diagram of the resonance circuit 10 of the present embodiment.
  • the coil 22 is formed of one-turn wiring, and the coil 22 is connected in series with the capacitor 24.
  • the width of the wiring is 0.5 mm.
  • the coil 22 is formed in a planar shape.
  • the transmission line 30 has conducting wires 32 and 34.
  • the conducting wire 32 is electrically connected to the LC circuit 20.
  • one end of the conducting wire 34 is electrically connected to the LC circuit 20, and typically the other end of the conducting wire 34 is grounded.
  • the conducting wire 32 may be referred to as a first conducting wire
  • the conducting wire 34 may be referred to as a second conducting wire.
  • the length L of the conducting wires 32 and 34 is approximately 1 ⁇ 4 of the wavelength corresponding to the predetermined frequency. Strictly speaking, this wavelength is not the wavelength in vacuum or air, but the wavelength of electromagnetic waves propagating through the conducting wires 32 and 34.
  • the transmission line 30 transmits electromagnetic waves using ⁇ / 4 TEM (Transverse Electromagnetic).
  • the first conducting wire 32 and the second conducting wire 34 are not short-circuited with each other, and the transmission line 30 is configured so that the impedance is substantially zero when viewed from the LC circuit 20.
  • the length L of the conducting wires 32 and 34 is approximately 1 ⁇ 4 of the wavelength corresponding to the predetermined frequency, but the present invention is not limited to this.
  • the length L of the conducting wires 32 and 34 may be an odd multiple of approximately 1 ⁇ 4 of the wavelength corresponding to the predetermined frequency.
  • FIG. 4 shows a schematic diagram of the resonance circuit 10 of the present embodiment.
  • a coaxial cable is used as the transmission line 30.
  • the first conducting wire 32 is used as an inner conductor (core wire) of the coaxial cable 30, and the second conducting wire 34 is used as an outer conductor of the coaxial cable 30.
  • An insulating member is provided between the conducting wire 32 and the conducting wire 34.
  • the insulating member is made of polyethylene, and the characteristic impedance of the coaxial cable 30 is about 50 ⁇ .
  • the capacitor 24 is provided closer to the coil 22 than the transmission line 30, but the present invention is not limited to this.
  • the capacitor 24 is connected in series to the coil 22, but the present invention is not limited to this.
  • FIG. 5 shows a schematic diagram of the resonance circuit 10 of the present embodiment.
  • capacitors 24 a and 24 b are provided between the coil 22 and the transmission line (coaxial cable) 30.
  • the capacitor 24 a is connected in series with the coil 22, and the capacitor 24 b is connected in parallel with the coil 22.
  • the capacitors 42 and 44 are provided on the opposite side of the coil 22 with respect to the transmission line (coaxial cable) 30.
  • the capacitors 42 and 44 are provided between the transmission line (coaxial cable) 30 and a control circuit (not shown) that controls the resonance circuit 10.
  • the capacitances of the capacitors 42 and 44 can be changed.
  • the capacitor 42 is provided in the resonance circuit 10 in order to match the transmission system with the same impedance.
  • the capacitor 44 is used for tuning, and is provided so that the circuit resonates at a specific frequency so that the electromagnetic wave can be easily received.
  • Such capacitors 42 and 44 are also called variable capacitors (variable capacitors).
  • the conducting wire 34 and the capacitor 44 are grounded.
  • the conducting wire 34 and the capacitor 44 may be grounded while being physically connected.
  • the capacitor 24 is provided at a location different from the coil 22, but the capacitor may be provided in the coil 22.
  • FIG. 6 shows a schematic diagram of the resonance circuit 10 of the present embodiment.
  • the coil 22 has wirings 22a and 22b separated from each other.
  • the width of the wirings 22a and 22b is about 0.5 mm.
  • the wirings 22a and 22b may be referred to as a first wiring 22a and a second wiring 22b.
  • the first wiring 22a and the second wiring 22b are connected. Is provided with a capacitor 24c.
  • the capacitor 24c is connected to both the first wiring 22a and the second wiring 22b.
  • the capacitor 24c is a chip capacitor.
  • an electromagnetic wave having a predetermined frequency can be transmitted and / or received via the control circuit (not shown) even if the configuration of the LC circuit 20 is slightly changed. For example, when the number of turns of the coil 22 is increased, the reception sensitivity of the electromagnetic wave can be improved.
  • the frequency of the electromagnetic wave resonating in the LC circuit 20 may be reduced, but a capacitor 24c is provided. As a result, a decrease in the resonance frequency of the resonance circuit 10 can be suppressed.
  • the coil 22 may be one turn. In general, the smaller the diameter of the coil 22, the more uniform the intensity of electromagnetic waves transmitted and received. On the other hand, as the diameter of the coil 22 is larger, the inductance is increased, and the distance between the coil 22 and a region where electromagnetic waves can be transmitted and received can be increased.
  • the coil 22 may be formed of a wiring having two or more turns.
  • FIG. 7 shows a schematic diagram of the resonance circuit 10 of the present embodiment.
  • the coil 22 has two turns.
  • the inductance increases and the distance between the coil 22 and the region where electromagnetic waves can be transmitted and received can be increased.
  • the wirings having different diameters are configured concentrically. In this case, since the coil 22 has wiring with different diameters, electromagnetic waves can be transmitted and received substantially uniformly over a relatively wide area.
  • the number of turns of the coil 22 is 2, but the present invention is not limited to this.
  • the number of turns of the coil 22 may be three or more.
  • FIG. 8 shows a schematic diagram of the resonance circuit 10 of the present embodiment.
  • the coil 22 has three turns.
  • the diameter (inner diameter) of the coil 22 is 10 mm or more.
  • the resonance circuit 10 includes capacitors 24a, 24b, 24c, 42, and 44.
  • the capacitances (capacitances) of the capacitors 24a, 24b, and 24c are about 1 pF, about 1 pF, and about 2 pF, respectively, and the capacitances (capacitances) of the capacitors 42 and 44 are all adjusted to 4 pF or less.
  • the length of the coil 22 is about 10 cm, and an alternating current of about 2.5 A flows through the coil 22.
  • the resonance frequency can be set to 500 MHz.
  • the hydrogen nuclei absorb and resonate with 500 MHz electromagnetic waves, and emit the absorbed electromagnetic waves.
  • the resonant circuit 10 can measure the state of hydrogen atoms in the sample by irradiating an electromagnetic wave having a frequency of 500 MHz and receiving the electromagnetic wave having a frequency of 500 MHz.
  • the coaxial cable 30 is about 15 cm.
  • the speed of the electromagnetic wave propagating through the coaxial cable 30 is smaller than that in vacuum or air and the shortening rate is larger than 1, strictly speaking, the coaxial cable 30 is shorter than 15 cm.
  • the diameter of the coil 22 is 10 mm or more and the capacitor 24c is provided. However, when the diameter of the coil 22 is small, the capacitor 24c may be omitted. However, since the diameter of the coil 22 is relatively large, the resonance circuit 10 can transmit and receive electromagnetic waves at a point relatively distant from the coil 22, and is suitable for imaging of the brain, spinal cord, and heart of a mouse, for example. Used.
  • FIG. 9A shows a schematic diagram in which the coil 22 of the resonance circuit 10 is arranged on the head of the mouse
  • FIG. 9B shows an example of an image obtained by using the resonance circuit 10.
  • FIG. 10 shows a resonance circuit 90 of a comparative example.
  • the resonance circuit 90 includes a two-turn coil 92 and capacitors 94a and 94b.
  • the capacitor 94 a is connected in series to the coil 92, and the capacitor 94 b is connected to the coil 92 in parallel.
  • FIGS. 11 and 12 show imaging results using the coil 92 of the resonance circuit 90 of the comparative example as a surface coil.
  • imaging was performed using a pulse sequence of multi-slice multi-echo (MSME).
  • MSME multi-slice multi-echo
  • the magnetic flux density is 11.7 T
  • the resonance frequency is 500 MHz.
  • FIGS. 12 (a) to 12 (f) are images obtained by slicing the phantom into 12 parts from the top.
  • AVANCE 500WB manufactured by Bruker as a magnetic resonance apparatus
  • imaging was performed with a coil 92 placed on the left side of the phantom.
  • white portions indicate portions where electromagnetic waves are strong, and move away from the resonance circuit 90 toward the right.
  • FIG. 13 and 14 show the imaging results using the resonance circuit 10 of the present embodiment.
  • imaging was performed using a multi-slice multi-echo (MSME) pulse sequence.
  • MSME multi-slice multi-echo
  • the magnetic flux density is 11.7 T
  • the resonance frequency is 500 MHz.
  • FIGS. 13 (a) to 13 (f) and FIGS. 14 (a) to 14 (f) are images obtained by slicing the phantom into 12 parts from the top.
  • AVANCE 500WB manufactured by Bruker as a magnetic resonance apparatus
  • imaging was performed with the coil 22 placed on the left side of the phantom.
  • the resonance circuit 10 of the present embodiment is more effective in the horizontal and vertical directions than the resonance circuit 10. Strong electromagnetic waves are obtained even in remote locations.
  • FIG. 15A shows a change in the intensity of the electromagnetic wave along the depth direction (the right direction of FIG. 12A), and
  • FIG. 15B shows the intensity of the electromagnetic wave along the width direction at the depth Da. Showing change.
  • a strong electromagnetic wave cannot be obtained even if the irradiation electromagnetic wave is too strong or too weak.
  • FIG. 16A shows a change in the intensity of the electromagnetic wave in the depth direction
  • FIG. 16B shows a change in the intensity of the electromagnetic wave in the width direction at the depth Db.
  • the electromagnetic wave is irradiated in a wide and deep range by using the coil 22 of the resonance circuit 10 as the surface coil. Due to the resonance circuit 10, the depth and width of the measurement region are improved about twice as much as those of the resonance circuit 90.
  • FIG. 17 (a) shows a diagram in which the head of a mouse is imaged by a FLASH (Fast Low-angle Shot) sequence with a Bruker AVANCE 500WB using the resonance circuit 90 of the comparative example.
  • the coil 92 of the resonance circuit 90 is used as a surface coil, the scalp close to the coil 92 is emphasized, while the sensitivity is drastically decreased in the left-right direction and the depth direction.
  • FIG. 17B is a diagram showing an image of the head of a mouse in a FLASH sequence with a Bruker AVANCE 500WB using the resonance circuit 10 of the present embodiment. As shown in FIG. 17B, when the coil 22 of the resonance circuit 10 is used as a surface coil, almost the entire head of the mouse can be imaged with high sensitivity.
  • the coil 22 of the resonant circuit 10 may be deformed according to the shape of the sample.
  • the coil 22 when viewed from the side, the coil 22 may be deformed so as to align with the convex portion of the sample (for example, the head of the mouse).
  • the coil 22 may be deformed so as to be aligned with the convex portion of the sample (for example, the head of the mouse) when viewed from the front.
  • the resonance circuit 10 of the present embodiment has 3 turns
  • the coil of the resonance circuit of the comparative example has 2 turns.
  • the resonance circuit 10 of the present embodiment has a ⁇ / 4 coaxial cable as the transmission line 30, whereas the resonance circuit of the comparative example does not have a transmission line.
  • FIG. 19A shows a cross-sectional view of the waist of the mouse using the resonance circuit of the comparative example
  • FIG. 19B shows the cross of the waist of the mouse using the resonance circuit 10 of the present embodiment. The figure which imaged the field is shown.
  • FIG. 19A and FIG. 19B when the resonance circuit of the comparative example is used, an image with sufficient sensitivity cannot be obtained.
  • FIG. 20 is a diagram in which blood vessels near the spinal cord of a mouse are imaged using the resonance circuit of the comparative example.
  • FIGS. 20 (a), 20 (b), and 20 (c) are sagittal planes, transverse sections, and coronal shapes. Each face is shown.
  • FIG. 21 is an image of blood vessels in the vicinity of the spinal cord of the mouse using the resonance circuit 10 of the present embodiment.
  • FIGS. 21 (a), 21 (b), and 21 (c) are sagittal planes and cross sections. And coronal plane respectively.
  • the resonance circuit of the comparative example When the resonance circuit of the comparative example is used, the blood vessel on the right side of the image farther than the blood vessel of the spinal cord (the arrow portion in FIGS. 20 (a) to 20 (c)) can be observed relatively well, whereas the periphery of the spinal cord The blood vessels are very difficult to see.
  • the resonance circuit 10 of the present embodiment when the resonance circuit 10 of the present embodiment is used, not only the spinal cord but also a deep abdominal aorta, branched blood vessels, and thick veins such as the inferior vena cava are also present. I can observe.
  • FIG. 22 shows an MRI image of the popliteal lymph node of the mouse imaged using the resonance circuit 10 of the present embodiment. As shown in FIG. 22, labeled immune cells are observed at the single cell level in the region surrounded by the arrow tip. Thus, by using the resonance circuit 10 of the present embodiment, observation can be performed at the single cell level.
  • one resonance circuit is used in the magnetic resonance apparatus, and one coil is provided in the resonance circuit.
  • the present invention is not limited to this.
  • a plurality of resonance circuits may be used in the magnetic resonance apparatus, or a plurality of coils may be provided in one resonance circuit.
  • a plurality of coils may be provided in one resonance circuit.
  • the resonance circuit 10 includes the transmission line 30, but the present invention is not limited to this.
  • the resonance circuit 10 that resonates at a frequency of 500 MHz or more may include the coil 22 having an inner diameter of 10 mm or more and 3 turns or more without including the transmission line 30.
  • the resonance circuit 10 can resonate at a frequency of 500 MHz or more without including the transmission line 30, and have the coil 22 having an inner diameter of 10 mm or more and 3 turns or more. it can.
  • the resonance circuit 10 that resonates at a frequency of 500 MHz or more may include a coil 22 having a diameter (inner diameter) of 10 cm or more and one turn or more.
  • the resonance circuit 10 receives electromagnetic waves from hydrogen nuclei, and the resonance circuit is used in a magnetic resonance imaging (MRI) apparatus, but the present invention is not limited to this.
  • the resonant circuit 10 may transmit or receive electromagnetic waves from nuclei other than hydrogen atoms.
  • a resonance circuit with improved sensitivity in the magnetic resonance method can be provided.
  • Such a resonance circuit is preferably used in a magnetic resonance method for a local area of a small animal or a person. Further, by realizing a multi-channel magnetic resonance apparatus by simultaneously using a plurality of coils of the resonance circuit according to the present invention, it is possible to suitably perform measurement for the entire human head and abdomen.

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  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)

Abstract

Le circuit à résonance (10) selon la présente invention est un circuit à résonance destiné à être utilisé dans un appareil à résonance magnétique. Le circuit de résonance (10) transmet, à un échantillon, des ondes électromagnétiques ayant une fréquence prédéfinie et/ou reçoit des ondes électromagnétiques provenant de l'échantillon et comprend : un circuit LC (20), constitué d'une bobine (22), et d'au moins une capacité (24) électriquement reliée à la bobine (22) ; et une voie de transmission (30) qui est électriquement reliée au circuit LC (20). La bobine (22) et la capacité (24) du circuit LC (20) sont conçues pour résonner à une fréquence différente de la fréquence prédéfinie, et le circuit LC (20) et la voie de transmission (30) sont conçus pour résonner à la fréquence prédéfinie.
PCT/JP2012/063325 2011-05-31 2012-05-24 Circuit à résonance WO2012165295A1 (fr)

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JP2011-122326 2011-05-31

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015147335A1 (fr) * 2014-03-27 2015-10-01 国立大学法人大阪大学 Diagnostic et traitement du paludisme cérébral
WO2021039104A1 (fr) * 2019-08-26 2021-03-04 国立研究開発法人科学技術振興機構 Dispositif de mesure de fibrose, procédé de mesure de fibrose et dispositif de mesure de propriété
JP7036809B2 (ja) 2016-10-10 2022-03-15 コーニンクレッカ フィリップス エヌ ヴェ 共平面ｒｆコイル給電

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