WO2024077687A1 - 一种具有空间选择性的磁共振***及其工作方法 - Google Patents

一种具有空间选择性的磁共振***及其工作方法 Download PDF

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WO2024077687A1
WO2024077687A1 PCT/CN2022/130123 CN2022130123W WO2024077687A1 WO 2024077687 A1 WO2024077687 A1 WO 2024077687A1 CN 2022130123 W CN2022130123 W CN 2022130123W WO 2024077687 A1 WO2024077687 A1 WO 2024077687A1
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coils
spectrometer
magnetic resonance
power
channel
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PCT/CN2022/130123
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English (en)
French (fr)
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赵越
罗海
王超
解运浩
胡剑雄
侯文魁
陈潇
吴敏
吴子岳
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无锡鸣石峻致医疗科技有限公司
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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
    • G01R33/34007—Manufacture of RF coils, e.g. using printed circuit board technology; additional hardware for providing mechanical support to the RF coil assembly or to part thereof, e.g. a support for moving the coil assembly relative to the remainder of the MR system
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves 
    • A61B5/055—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
    • 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
    • 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
    • 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
    • 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
    • G01R33/42—Screening
    • 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
    • G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/48—NMR imaging systems
    • G01R33/54—Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console

Definitions

  • the invention belongs to the field of magnetic resonance technology, and in particular relates to a magnetic resonance system with spatial selectivity and a working method thereof.
  • the single-sided magnet magnetic resonance system When performing magnetic resonance detection on a single-sided magnet magnetic resonance system, since the single-sided magnet magnetic resonance system is generally not equipped with a gradient system that can be used for spatial encoding, the collected signals are often mixed signals from various tissues. When analyzing the pathological condition of a specific tissue, signals from other surrounding tissues will affect the analysis results, which may lead to detection errors.
  • a magnetic resonance system with spatial selectivity can remove signals outside the target area as needed, so it is of great significance in magnetic resonance detection.
  • the existing spatially selective magnetic resonance detection methods mainly include layer-selected gradient method, saturation pulse method, three-dimensional spatial selection sequence and spatially selective radio frequency pulse.
  • the layer-selected gradient method selects one or more planes in any orientation through layer-selected gradient
  • the saturation pulse method realizes arbitrary area selection or removes non-target area signals through multiple saturation pulses
  • the three-dimensional spatial selection sequence such as the PRESS sequence or the STEAM sequence, can select a cubic area
  • the spatially selective radio frequency pulse can excite a plane with a local area, thereby realizing the target area selection.
  • the purpose of the present invention is to provide a magnetic resonance system with spatial selectivity and a working method thereof, so as to solve the technical problem in the prior art that a complex gradient system is required to achieve spatial selectivity, resulting in a high detection cost of the magnetic resonance system.
  • a magnetic resonance system with spatial selectivity comprising: a data display processing module, a spectrometer with at least one transmission channel, at least one power amplifier connected to the transmission channel of the spectrometer in a one-to-one correspondence, a TR switch, a preamplifier, a plurality of coils, and a magnet module;
  • the data display processing module is connected to the spectrometer, the spectrometer is respectively connected to the at least one power amplifier, the TR switch and the preamplifier, and the TR switch is respectively connected to the preamplifier and a main coil corresponding to the target area;
  • the spectrometer includes any combination of a single-channel emission spectrometer and/or a multi-channel emission spectrometer.
  • the number of emission channels of the combined spectrometer is not less than the number of coils, one of the power amplifiers is connected to the TR switch, and the other power amplifiers are connected one-to-one with the other coils except the main coil;
  • the output end of at least one of the power amplifiers is connected to at least one power divider, and the output end of at least one power divider is connected to phase shifters corresponding to the number of coils, at which time one of the phase shifters or the power amplifier is connected to the TR switch, and the remaining phase shifters are connected one-to-one with the other coils except the main coil;
  • the radio frequency field and excitation area generated by each set of coils are different, and the difference between the radio frequency field generated by the main coil corresponding to the target area and the radio frequency fields generated by other coils is greater than a preset value.
  • it includes multiple single-channel emission spectrometers or at least one multi-channel emission spectrometer, and also includes multiple power amplifiers connected one-to-one with each emission channel, wherein the output end of one power amplifier is connected to the TR switch, and the other power amplifiers are connected one-to-one with other coils except the main coil.
  • it includes a single-channel emission spectrometer or a multi-channel emission spectrometer with only one emission channel working, and also includes a power amplifier connected to the emission channel, the output end of the power amplifier is connected to the input end of a power divider, the output end of the power divider is connected to multiple phase shifters, one of the phase shifters is connected to the TR switch, and the remaining phase shifters are connected one-to-one with other coils except the main coil.
  • it includes multiple single-channel emission spectrometers or at least one multi-channel emission spectrometer, and also includes multiple power amplifiers connected one-to-one with each emission channel, wherein the output end of one power amplifier is connected to the TR switch, and the other power amplifiers are connected to a power divider, and the output end of the power divider is connected to multiple phase shifters, and each phase shifter is connected one-to-one with other coils except the main coil.
  • it includes multiple single-channel emission spectrometers or at least one multi-channel emission spectrometer, and also includes multiple power amplifiers, the output end of each power amplifier is connected to a power divider, the output end of each power divider is connected to multiple phase shifters, one of the phase shifters is connected to the TR switch, and the remaining phase shifters are connected one-to-one with other coils except the main coil.
  • it includes two single-channel emission spectrometers or a multi-channel emission spectrometer with only two emission channels working, and the output end of each emission channel is connected to a power amplifier.
  • a second aspect provides a method for operating a magnetic resonance system with spatial selectivity as described in any possible design of the first aspect, comprising:
  • the magnetic resonance signals generated in the main coil excitation area are returned to the data processing and display module through the TR switch, preamplifier and spectrometer in sequence to achieve spatial selection of the magnetic resonance signals in the target area.
  • the working method further includes:
  • the phase and amplitude of the first saturation pulse are adjustable to maximally saturate the magnetic resonance signals in the excitation regions of other coils.
  • the working method further includes:
  • a third instruction is sent to the spectrometer through the data display module so that the spectrometer controls coils other than the main coil to emit different second saturation pulses through multiple power amplifiers according to the third instruction, or controls coils other than the main coil to emit different second saturation pulses through power amplifiers, power dividers and phase shifters in sequence.
  • the main pulse sequence includes a CPMG sequence.
  • the present invention has the following beneficial effects:
  • the present invention sets a magnetic resonance radio frequency system to include any combination of a single-channel emission spectrometer and/or a multi-channel emission spectrometer, and correspondingly sets a plurality of power amplifiers or a combination of power amplifiers, power dividers and phase shifters, and sets a plurality of sets of coils including a main coil and other coils, wherein the radio frequency field and excitation area generated by each set of coils are different, and the difference between the radio frequency field generated by the main coil corresponding to the target area and the radio frequency field generated by the other coils is greater than a preset value; thus, when the system is working, according to the needs of the target area to be selected, the spectrometer can control the plurality of coils through the plurality of power amplifiers to simultaneously emit a main pulse sequence for excitation, or control the plurality of coils through the power amplifiers, power dividers and phase shifters to simultaneously emit a main pulse sequence for excitation, so that the magnetic resonance signal intensities obtained at the same flip angle in each
  • FIG1 is a schematic diagram of a first structure of a magnetic resonance system with spatial selectivity in an embodiment of the present application
  • FIG2 is a schematic diagram of a second structure of a magnetic resonance system with spatial selectivity in an embodiment of the present application
  • FIG3 is a schematic diagram of a third structure of a magnetic resonance system with spatial selectivity in an embodiment of the present application.
  • FIG4 is a schematic diagram of a fourth structure of a magnetic resonance system with spatial selectivity in an embodiment of the present application.
  • FIG5 is a schematic diagram of one excitation area of multiple sets of coils in an embodiment of the present application.
  • FIG6 is a flow chart of a working method of a magnetic resonance system with spatial selectivity in an embodiment of the present application
  • FIG7 is a schematic diagram of a first pulse sequence of multiple sets of coils in an embodiment of the present application.
  • FIG8 is a schematic diagram of a second pulse sequence of multiple sets of coils in an embodiment of the present application.
  • FIG9 is a schematic diagram of a third pulse sequence of multiple sets of coils in an embodiment of the present application.
  • FIG. 10 is a schematic diagram of a phantom excitation structure of an experimental example in an embodiment of the present application.
  • an embodiment of the present application provides a magnetic resonance system with spatial selectivity, which can achieve spatial selection of a target area without the support of a gradient system, thereby reducing the cost and complexity of magnetic resonance detection.
  • the magnetic resonance system with spatial selectivity includes: a data display processing module, a spectrometer with at least one transmission channel, at least one power amplifier connected to the transmission channel of the spectrometer in a one-to-one correspondence, a TR switch, a preamplifier, a plurality of coils, and a magnet module;
  • the data display processing module is connected to the spectrometer, the spectrometer is respectively connected to the at least one power amplifier, the TR switch and the preamplifier, and the TR switch is respectively connected to the preamplifier and a main coil corresponding to the target area;
  • the spectrometer includes any combination of a single-channel emission spectrometer and/or a multi-channel emission spectrometer.
  • the number of emission channels of the combined spectrometer is not less than the number of coils, one of the power amplifiers is connected to the TR switch, and the other power amplifiers are connected one-to-one with the other coils except the main coil;
  • the output end of at least one of the power amplifiers is connected to at least one power divider, and the output end of at least one power divider is connected to phase shifters corresponding to the number of coils, at which time one of the phase shifters or the power amplifier is connected to the TR switch, and the remaining phase shifters are connected one-to-one with the other coils except the main coil;
  • the radio frequency field and excitation area generated by each set of coils are different, and the difference between the radio frequency field generated by the main coil corresponding to the target area and the radio frequency field generated by the other coils is greater than a preset value;
  • the spectrometer, power amplifier, TR switch, preamplifier, multiple sets of coils, power divider, phase shifter and magnet module together constitute the RF radio frequency module.
  • the size of the RF field and the excitation area generated by each coil can be designed according to the corresponding winding method, shape, placement position and/or matching and tuning capacitance on the coil when designing the coil, so as to achieve the effect that the RF field and excitation area generated by each set of coils are different, and the difference between the RF field generated by the main coil corresponding to the target area and the RF field generated by other coils is greater than the preset value.
  • the data processing and display module is used to send instructions to control the radio frequency pulse sequence and receive magnetic resonance signals to complete real-time data processing;
  • the spectrometer is used to control the radio frequency pulse sequence and receive magnetic resonance signals;
  • the input end of each power amplifier is connected to one of the transmission channels of the spectrometer, which is used to amplify the radio frequency pulses output by the spectrometer;
  • the TR switch is used to control the transceiver conversion of the link where the main coil corresponding to the target area is located;
  • the preamplifier is used to amplify the received magnetic resonance signal;
  • the magnet module is used to generate a static magnetic field B0;
  • the multiple sets of radio frequency coil systems are used to generate multiple radio frequency fields B1 perpendicular to the static magnetic field B0.
  • spectrometers there are many combinations of spectrometers, power amplifiers, power dividers and phase shifters in the embodiments of the present application, including but not limited to when the number of transmitting channels of the combined spectrometer is not less than the number of coils, only multiple power amplifiers connected one-to-one with the transmitting channels are set, or when the number of transmitting channels of the combined spectrometer is less than the number of coils, the power division and phase adjustment of the RF pulses are achieved by setting a combination of power amplifiers, power dividers and phase shifters, for example, a single power amplifier and multiple power dividers, phase shifters and multiple sets of coils corresponding to a spectrometer with a single transmitting channel; multiple power amplifiers and multiple power dividers, phase shifters and multiple sets of coils corresponding to a spectrometer with multiple transmitting channels; flexible combinations of multiple spectrometers, multiple power amplifiers and power dividers, etc., which will not be described one by one here.
  • the magnetic resonance system includes multiple single-channel emission spectrometers or at least one multi-channel emission spectrometer, and also includes multiple power amplifiers connected one-to-one with each emission channel, wherein the output end of one power amplifier is connected to the TR switch, and the other power amplifiers are connected one-to-one with other coils except the main coil.
  • the entire system includes a data processing and display module, which is used to connect to the spectrometer, send instructions to control the radio frequency pulse sequence and receive magnetic resonance signals to complete real-time data processing; multiple single-channel emission spectrometers or a multi-channel emission magnetic resonance spectrometer, which is used to control the radio frequency pulse sequence and receive magnetic resonance signals; multiple power amplifiers, whose input ends are connected to multiple emission channels of the spectrometer and whose output ends are connected to TR switches or multiple radio frequency coils, which are used to amplify the radio frequency pulses output by the spectrometer; a TR switch, which is used to control the transceiver conversion of the link where the coil corresponding to the target area is located; a preamplifier, which is used to amplify the received magnetic resonance signal; a magnet module, which is used to generate a static magnetic field B0; and multiple sets of radio frequency coil systems, which are used to generate multiple radio frequency fields B1 perpendicular to the static magnetic field B0.
  • the magnetic resonance system includes a single-channel emission spectrometer or a multi-channel emission spectrometer with only one emission channel working, and also includes a power amplifier connected to the emission channel, the output end of the power amplifier is connected to the input end of a power divider, the output end of the power divider is connected to multiple phase shifters, one of the phase shifters is connected to the TR switch, and the remaining phase shifters are connected one-to-one with other coils except the main coil.
  • the entire system includes a data processing and display module, which is used to connect to the spectrometer, send instructions to control the RF pulse sequence and receive magnetic resonance signals to complete real-time data processing; a single-channel transmission magnetic resonance spectrometer or a multi-channel transmission spectrometer with only one transmission channel working, which is used to control the RF pulse sequence and receive magnetic resonance signals; a power amplifier, whose input end is connected to a transmission channel of the spectrometer and whose output end is connected to the input of a multi-channel power divider, which is used to amplify the RF pulse output by the spectrometer.
  • a data processing and display module which is used to connect to the spectrometer, send instructions to control the RF pulse sequence and receive magnetic resonance signals to complete real-time data processing
  • a single-channel transmission magnetic resonance spectrometer or a multi-channel transmission spectrometer with only one transmission channel working which is used to control the RF pulse sequence and receive magnetic resonance signals
  • a power amplifier whose input end is connected
  • the power amplifier used in a system with only one power amplifier usually has a very high output power to meet the system requirements; a power divider, which is used to divide the RF power of one input RF pulse into multiple channels; multiple phase shifters, which are used to adjust the phase of the RF pulses output by each power divider; a TR switch, which is used to control the transceiver conversion of the link where the coil corresponding to the target area is located; a preamplifier, which is used to amplify the received magnetic resonance signal; a magnet module, which is used to generate a static magnetic field B0; and multiple sets of RF coil systems, which are used to generate multiple RF fields B1 perpendicular to the static magnetic field B0.
  • the magnetic resonance system includes multiple single-channel emission spectrometers or at least one multi-channel emission spectrometer, preferably, includes two single-channel emission spectrometers or a multi-channel emission spectrometer with only two channels working, and also includes multiple power amplifiers connected one-to-one with each emission channel, wherein the output end of one power amplifier is connected to the TR switch, and the other power amplifiers are connected to a power divider, the output end of the power divider is connected to multiple phase shifters, and each phase shifter is connected one-to-one with other coils except the main coil.
  • the whole system includes a data processing and display module, which is used to connect with the spectrometer, send instructions to control the radio frequency pulse sequence and receive magnetic resonance signals to complete real-time data processing; multiple single-channel emission spectrometers or a multi-channel emission magnetic resonance spectrometer, which is used to control the radio frequency pulse sequence and receive magnetic resonance signals; multiple power amplifiers, wherein the output end of one of the power amplifiers is connected to the TR switch, and the other power amplifiers are connected to a power divider.
  • a data processing and display module which is used to connect with the spectrometer, send instructions to control the radio frequency pulse sequence and receive magnetic resonance signals to complete real-time data processing
  • multiple single-channel emission spectrometers or a multi-channel emission magnetic resonance spectrometer which is used to control the radio frequency pulse sequence and receive magnetic resonance signals
  • multiple power amplifiers wherein the output end of one of the power amplifiers is connected to the TR switch, and the other power amplifiers are connected to a power divider.
  • the output end of one of the power amplifiers can also be connected to the TR switch, and a part of the other power amplifiers can be directly connected to the radio frequency coil, and the other part of the power amplifiers can be connected to the radio frequency coil after the power divider and the phase shifter, so as to amplify the radio frequency pulse output by the spectrometer; multiple power dividers, which are used to divide the radio frequency power of the input radio frequency pulse into multiple paths, and multiple phase shifters, which are used to adjust the phase of the radio frequency pulses output by each power divider; a TR switch, which is used to control the transceiver conversion of the link where the coil corresponding to the target area is located; a preamplifier, which is used to amplify the received magnetic resonance signal; a magnet module, which is used to generate a static magnetic field B0; and multiple sets of radio frequency coil systems, which are used to generate multiple radio frequency fields B1 perpendicular to the static magnetic field B0.
  • the magnetic resonance system includes multiple single-channel emission spectrometers or at least one multi-channel emission spectrometer, preferably, includes two single-channel emission spectrometers or a multi-channel emission spectrometer with only two emission channels working, and also includes multiple power amplifiers, each power amplifier The output end is connected to a power divider, and the output end of each power divider is connected to a plurality of phase shifters, one of which is connected to the TR switch, and the remaining phase shifters are connected one-to-one with other coils except the main coil.
  • the entire system includes a data processing and display module, which is used to connect to the spectrometer, send instructions to control the RF pulse sequence and receive magnetic resonance signals to complete real-time data processing; multiple single-channel emission spectrometers or a multi-channel emission magnetic resonance spectrometer, which is used to control the RF pulse sequence and receive magnetic resonance signals; multiple power amplifiers, each of which is connected to a power divider and a phase shifter and then connected to the RF coil, for amplifying the RF pulses output by the spectrometer; multiple power dividers, which are used to divide the RF power of the input RF pulse into multiple paths; multiple phase shifters, which are used to adjust the phase of the RF pulses output by each power divider; a TR switch, which is used to control the transceiver conversion of the link where the coil is located in the target area; a preamplifier, which is used to amplify the received magnetic resonance signal; a magnet module, which is used to generate a static magnetic field B0;
  • each magnetic resonance radio frequency system in the embodiment of the present application includes multiple sets of radio frequency coils, and the radio frequency fields and excitation areas generated by each set of radio frequency coils are different. Multiple sets of radio frequency coils are excited simultaneously to achieve the purpose of spatial selection.
  • 1, 2, 3, and 4 represent four different sets of radio frequency coils, where 1 is the main coil, corresponding to four different excitation areas 5, 6, 7, and 8, 9 is the target tissue area to be detected, and 10 is other tissues around the target area.
  • the macroscopic magnetization vector formed by the spin rotates around the radio frequency field B1.
  • the macroscopic magnetization vector generated by the spin is turned 90 degrees by a radio frequency pulse with a certain flip angle (i.e., radio frequency power)
  • the maximum transverse magnetization vector is obtained.
  • the transverse magnetization vector is the magnetic resonance signal, so the signal size is closely related to the radio frequency field B1 and the corresponding radio frequency pulse flip angle. If only the main coil 1 in the figure is used for excitation, the collected magnetic resonance signal must contain the signal of the surrounding tissue 10 in addition to the target tissue area 9, which will reduce the accuracy of the detection. Based on this, this embodiment is based on the above-disclosed magnetic resonance system and proposes a working method of the system to achieve spatial selection of the target area.
  • the second aspect of the embodiment of the present application provides a working method of a magnetic resonance system with spatial selectivity as described in any possible design of the first aspect, including but not limited to being implemented by steps S1-S3:
  • Step S Sending a first instruction to the spectrometer through the data processing and display module;
  • Step S2 Controlling multiple sets of coils to simultaneously transmit a main pulse sequence through multiple power amplifiers according to the first instruction by a spectrometer, or controlling multiple sets of coils to simultaneously transmit a main pulse sequence through power amplifiers, power dividers and phase shifters in sequence, so that the difference between the radio frequency field of the first area and the radio frequency field of the target area is greater than a threshold, wherein the first area is an overlapping area between the excitation area of the main coil and the excitation areas of the other coils;
  • a radio frequency field with spatial selectivity will be synthesized.
  • the amplitude and phase of the transmission signal are controlled by different transmission channels of the spectrometer, or the phase is controlled by a phase shifter, so that the radio frequency field in the overlapping area of the main coil 1 and other coils is greatly different from the radio frequency field in the target area, thereby achieving spatial excitation selectivity.
  • coils 1, 2, 3, and 4 are used for simultaneous excitation.
  • the macroscopic magnetization vector generated by the spin in the excitation area of coil 1 is turned to 90 degrees, because the radio frequency field generated by coils 2, 3, and 4 is greatly different from the radio frequency field generated by coil 1, the macroscopic magnetization vector generated by the spin in the excitation area of coils 2, 3, and 4 is not turned to 90 degrees or far exceeds 90 degrees, showing a low signal, and the excitation area of coil 1 except for the area overlapping with the excitation area of coils 2, 3, and 4 (i.e., the target area) shows a high signal, that is, the target tissue area shows a high signal, thereby achieving the purpose of spatial selection.
  • coils 1 to coil n simultaneously transmit a main pulse sequence
  • the main pulse sequence is any radio frequency pulse that can excite magnetic resonance signals, including but not limited to a CPMG pulse sequence.
  • the radio frequency field B1 Under the action of the radio frequency field B1, the macroscopic magnetization vector formed by the spin rotates around the radio frequency field B1.
  • the radio frequency field B1 generated by coil 1 and the radio frequency field B1 generated by coils 2-n are designed to have a large difference. All coils are excited by radio frequency pulses with the same flip angle.
  • the flip angle of the radio frequency pulse meets the flip angle corresponding to the radio frequency field B1 generated by coil 1, that is, a high signal is presented in the excitation area of coil 1, and a low signal is presented in the excitation area of coil 2-n.
  • the target area of interest is the excitation area of coil 1 excluding the excitation area of other coils 2 to n.
  • the magnetic resonance signal in the excitation area of coil 1 is received.
  • the excitation area of coil 1 excluding the excitation area of other coils 2 to n presents a high signal
  • the overlapping area of coil 1 excitation area and the excitation area of other coils 2 to n presents a low signal, thereby achieving the effect of spatial selection.
  • the working method further includes:
  • the phase and amplitude of the first saturation pulse are adjustable to maximally saturate the magnetic resonance signals in the excitation regions of other coils.
  • coils 2-n first simultaneously transmit the same saturation pulse, and then all coils transmit a main pulse sequence of RF pulses with the same flip angle.
  • the flip angle of the RF pulse satisfies the flip angle corresponding to the RF field B1 generated by coil 1, that is, a high signal is presented in the excitation area of coil 1, and no signal is presented in the excitation area of coil 2-n.
  • the target area of interest is the excitation area of coil 1 excluding the excitation areas of other coils 2 to n, and the magnetic resonance signal in the excitation area of coil 1 is received.
  • the excitation area of coil 1 excluding the excitation areas of other coils 2 to n presents a high signal, and the overlapping area between the excitation area of coil 1 and the excitation areas of other coils 2 to n presents no signal, thereby achieving the effect of spatial selection.
  • the working method further includes:
  • a third instruction is sent to the spectrometer through the data display module so that the spectrometer controls coils other than the main coil to emit different second saturation pulses through multiple power amplifiers according to the third instruction, or controls coils other than the main coil to emit different second saturation pulses through power amplifiers, power dividers and phase shifters in sequence.
  • each coil in coils 2-n can select different saturation pulses according to actual conditions, which can be different flip angles and different shapes, and then all coils transmit a main pulse sequence of RF pulses with the same flip angle, and the flip angle of the RF pulse satisfies the flip angle corresponding to the RF field B1 generated by coil 1, that is, a high signal is presented in the excitation area of coil 1, and no signal is presented in the excitation area of coil 2-n.
  • the target area of interest is the excitation area of coil 1 excluding the excitation areas of other coils 2 ⁇ n, and the magnetic resonance signal in the excitation area of coil 1 is received.
  • the excitation area of coil 1 excluding the excitation areas of other coils 2 ⁇ n presents a high signal, and the overlapping area between the excitation area of coil 1 and the excitation areas of other coils 2 ⁇ n presents no signal, thereby achieving the effect of spatial selection.
  • Step S3 The magnetic resonance signal generated in the main coil excitation area is returned to the data processing and display module through the TR switch, the preamplifier and the spectrometer in sequence, so as to realize the spatial selection of the magnetic resonance signal in the target area.
  • the embodiment of the present application sets the magnetic resonance radio frequency system to include any combination of a single-channel emission spectrometer and/or a multi-channel emission spectrometer, and correspondingly sets multiple power amplifiers or a combination of power amplifiers, power dividers and phase shifters, and sets multiple sets of coils including a main coil and other coils.
  • the radio frequency field and excitation area generated by each set of coils are different, and the difference between the radio frequency field generated by the main coil corresponding to the target area and the radio frequency field generated by the other coils is greater than a preset value; so that when the system is working, according to the needs of the target area to be selected, the spectrometer controls multiple power amplifiers to simultaneously transmit a main pulse sequence to multiple sets of coils for excitation, or sequentially controls the power amplifier, power divider and phase shifter to simultaneously transmit a main pulse sequence to multiple sets of coils for excitation, so that the magnetic resonance signal intensities obtained at the same flip angle in each different radio frequency field and excitation area have a large difference, thereby realizing the spatial selection of the magnetic resonance signal of the target area, improving the accuracy of magnetic resonance signal detection, and the whole process does not require the support of the gradient system, reducing the cost and complexity of magnetic resonance detection.
  • the present application proposes an experimental example to illustrate the feasibility of the system and the working method thereof, as follows:
  • FIG10 a schematic diagram of the relative positions of a magnet module, a coil module and a measurement model of a magnetic resonance system with spatial selectivity is shown, wherein 1 is a main coil with a relatively large excitation area and an excitation depth of 8 cm, coils 2, 3, and 4 have relatively small excitation areas and an excitation depth of 3.5 cm, which are placed on a magnet 5, and a 3-cm thick rectangular oil model 6 and a cylindrical oil model 7 with a diameter of 8 cm and a height of 12 cm are placed on the surface of the coil.
  • this verification example uses a system of a dual-channel emission spectrometer, two power amplifiers, and two two-way power dividers as shown in FIG4 .
  • the main pulse sequence selects a CPMG sequence for measuring the signal-to-noise ratio, and the following experiments are performed successively:
  • the shallow oil pad was removed and replaced with a dry wooden board of the same thickness.
  • the deep oil pad kept its original spatial position unchanged, and the measured signal-to-noise ratio was 14.
  • the signal-to-noise ratio is measured to be 2;
  • the signal-to-noise ratio was measured to be 16;
  • the shallow oil pad was removed and replaced with a dry wooden board of the same thickness.
  • the deep oil pad kept its original spatial position unchanged, and the measured signal-to-noise ratio was 16.
  • the signal-to-noise ratio was measured to be 0.8;
  • a deep oil mold was added to the shallow oil cushion, and the signal-to-noise ratio was measured to be 16;
  • the shallow oil pad was removed and replaced with a dry wooden board of the same thickness.
  • the deep oil pad kept its original spatial position unchanged, and the measured signal-to-noise ratio was 16.

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Abstract

一种具有空间选择性的磁共振***及其工作方法，***包括数据显示处理模块、至少设有一个发射通道的谱仪、与谱仪发射通道一一对应连接的至少一个功率放大器、TR开关、前置放大器、多套线圈以及一磁体模块；当谱仪发射通道数量不小于线圈数量时，一功率放大器与TR开关连接，其他功率放大器与除主线圈(1)外的其他线圈(2,3,4)对应连接；当谱仪发射通道数量小于线圈数量时，至少一个功率放大器的输出端连接有至少一个功分器和多个移相器再与线圈连接；每套线圈产生的射频场和激发区域各不相同，主线圈(1)产生与其他线圈(2,3,4)产生的射频场的差异大于预设值。无需梯度***的支持即可实现目标区域信号的空间选择，降低了磁共振检测的成本和难度。

Description

一种具有空间选择性的磁共振***及其工作方法 技术领域
本发明属于磁共振技术领域，具体涉及一种具有空间选择性的磁共振***及其工作方法。
背景技术
在单边磁体磁共振***上进行磁共振检测时，由于单边磁体磁共振***一般不配备可用于空间编码的梯度***，因此采集到的信号往往是各个组织的混合信号，在分析某一特定组织的病理情况时，来自周边的其他组织信号会影响分析结果，进而可能导致检测错误。具有空间选择性的磁共振***能够按需去除目标区域之外的信号，因此在磁共振检测中具有重大意义。
现有的具有空间选择性的磁共振检测方法主要包括层选梯度法、饱和脉冲法、三维空间选择序列以及空间选择性射频脉冲。其中，层选梯度法通过层选梯度，选择任意方位的一个或多个平面；饱和脉冲法通过多个饱和脉冲实现任意区域选择或去除非目标区域信号；三维空间选择序列，例如PRESS序列或STEAM序列，能够选择得到一个立方体区域；空间选择性射频脉冲能够激发一个具有局部区域的平面，从而实现目标区域选择。
然而，上述各空间选择性的实现方法，均需要复杂梯度***的支持才能实现空间选择性，导致磁共振***检测成本较高。
发明内容
本发明的目的是提供一种具有空间选择性的磁共振***及其工作方法，用以解决现有技术中存在的需要复杂梯度***的支持才能实现空间选择性，导致磁共振***检测成本较高的技术问题。
为了实现上述目的，本发明采用以下技术方案：
第一方面提供一种具有空间选择性的磁共振***，包括：数据显示处理模块、至少设有一个发射通道的谱仪、与谱仪发射通道一一对应连接的至少一个功率放大器、TR开关、前置放大器、多套线圈以及一磁体模块；
所述数据显示处理模块与所述谱仪连接，所述谱仪分别与所述至少一个功率放大器、所述TR开关以及所述前置放大器连接，所述TR开关分别与所述前置放大器以及与目标区域对应的主线圈连接；
所述谱仪包括单通道发射谱仪和/或多通道发射谱仪的任意组合，当组合后的谱仪的发射通道数量不小于线圈数量时，其中一个功率放大器与TR开关连接，其他功率放大器与除主线圈外的其他线圈一一对应连接；当组合后的谱仪的发射通道数量小于线圈数量时，至少一个所述功率放大器的输出端连接有至少一个功分器，至少一个功分器的输出端连接有与线圈数量对应的移相器，此时其中一个移相器或功率放大器与所述TR开关连接，剩余移相器与除主线圈外的其他线圈一一对应连接；
其中，每套线圈产生的射频场和激发区域各不相同，与目标区域对应的主线圈产生的射频场与其他线圈产生的射频场之间的差异大于预设值。
在一种可能的设计中，包括多个单通道发射谱仪或至少一个多通道发射谱仪，还包括与每一发射通道一一对应连接的多个功率放大器，其中一个功率放大器的输出端与所述TR开关连接，其他功率放大器与除主线圈外的其他线圈一一对应连接。
在一种可能的设计中，包括一个单通道发射谱仪或者仅一个发射通道工作的多通道发射谱仪，还包括一个与该发射通道连接的功率放大器，功率放大器的输出端与一功分器的输入端连接，功分器的输出端与多个移相器连接，其中一个移相器所述TR开关连接，剩余移相器与除主线圈外的其他线圈一一对应连接。
在一种可能的设计中，包括多个单通道发射谱仪或至少一个多通道发射谱仪，还包括与每一发射通道一一对应连接的多个功率放大器，其中一个功率放大器的输出端与所述TR开关连接，其他功率放大器与一功分器连接，功分器的输出端与多个移相器连接，每一移相器与除主线圈外的其他线圈一一对应连接。
在一种可能的设计中，包括多个单通道发射谱仪或至少一个多通道发射谱仪，还包括多个功率放大器，每一功率放大器的输出端连接有一功分器，每一功分器的输出端连接有多个移相器，其中一个移相器与TR开关连接，剩余移相器与除主线圈外的其他线圈一一对应连接。
在一种可能的设计中，包括两个单通道发射谱仪或仅两个发射通道工作的一个多通道发射谱仪，每一发射通道的输出端连接有一个功率放大器。
第二方面提供一种如第一方面任意一种可能的设计中所述的具有空间选择性的磁共振***的工作方法，包括：
通过数据处理显示模块向谱仪发送第一指令；
通过谱仪根据第一指令通过多个功率放大器控制多套线圈同时发射主脉冲序列，或依次通过功率放大器、功分器和移相器控制多套线圈同时发射主脉冲序列，以便第一区域的射频场与目标区域的射频场之间的差异大于阈值，其中，第一区域为主线圈的激发区域和其他线圈的激发区域之间的重叠区域；
将主线圈激发区域产生的磁共振信号依次通过TR开关、前置放大器和谱仪返回至数据处理显示模块，实现目标区域磁共振信号的空间选择。
在一种可能的设计中，在通过谱仪根据第一指令通过多个功率放大器控制多套线圈同时发射主脉冲序列之前，所述工作方法还包括：
通过数据显示模块向谱仪发送第二指令，以便谱仪根据第二指令通过多个功率放大器控制除主线圈外的其他线圈同时发射相同的第一饱和脉冲，或依次通过功率放大器、功分器和移相器控制除主线圈外的其他线圈同时发射相同的第一饱和脉冲；
其中，所述第一饱和脉冲的相位和幅值均可调，以最大限度饱和其他线圈的激发区域内的磁共振信号。
在一种可能的设计中，在通过谱仪根据第一指令通过多个功率放大器控制多套线圈同时发射主脉冲序列之前，所述工作方法还包括：
通过数据显示模块向谱仪发送第三指令，以便谱仪根据第三指令通过多个功率放大器控制除主线圈外的其他线圈发射不同的第二饱和脉冲，或依次通过功率放大器、功分器和移相器控制除主线圈外的其他线圈发射不同的第二饱和脉冲。
在一种可能的设计中，所述主脉冲序列包括CPMG序列。
本发明相较于现有技术的有益效果为：
本发明通过将磁共振射频***设置为包括单通道发射谱仪和/或多通道发射谱仪的任意组合，对应设置多个功率放大器或者功率放大器、功分器和移相器的组合，同时设置包含主线圈和其他线圈的多套线圈，每套线圈产生的射频场和激发区域各不相同，与目标区域对应的主线圈产生的射频场与其他线圈产生的射频场之间的差异大于预设值；从而***在工作时，可根据待选择的目标区域的需求，由谱仪通过多个功率放大器控制多套线圈同时发射主脉冲序列来进行激发，或依次通过功率放大器、功分器和移相器控制多套线圈同时发射主脉冲序列来进行激发，从而使得各个不相同的射频场和激发区域在同一翻转角下获得的磁共振信号强度具有较大差异，进而实现目标区域磁共振信号的空间选择，提高磁共振信号检测的准确性，整个过程无需梯度***的支持，降低了磁共振检测的成本和复杂度。
附图说明
图1为本申请实施例中的具有空间选择性的磁共振***的第一种结构示意图；
图2为本申请实施例中的具有空间选择性的磁共振***的第二种结构示意图；
图3为本申请实施例中的具有空间选择性的磁共振***的第三种结构示意图；
图4为本申请实施例中的具有空间选择性的磁共振***的第四种结构示意图；
图5为本申请实施例中的多套线圈的其中一种激发区域示意图；
图6为本申请实施例中的具有空间选择性的磁共振***的工作方法的流程图；
图7为本申请实施例中的多套线圈的第一种脉冲序列的示意图；
图8为本申请实施例中的多套线圈的第二种脉冲序列的示意图；
图9为本申请实施例中的多套线圈的第三种脉冲序列的示意图；
图10为本申请实施例中的实验例的模体激发结构示意图。
具体实施方式
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将结合附图和实施例或现 有技术的描述对本发明作简单地介绍，显而易见地，下面关于附图结构的描述仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。在此需要说明的是，对于这些实施例方式的说明用于帮助理解本发明，但并不构成对本发明的限定。
实施例
为了解决现有技术中存在的需要复杂梯度***的支持才能实现空间选择性，导致磁共振***检测成本较高的技术问题；本申请实施例提供了一种具有空间选择性的磁共振***，该***无需梯度***的支持即能够实现目标区域的空间选择，降低了磁共振检测的成本和复杂度。
下面将对本申请实施例提供的具有空间选择性的磁共振***进行详细说明。
如图1-图5所示，是本申请实施例提供的具有空间选择性的磁共振***的多种结构示意图，所述具有空间选择性的磁共振***，包括：数据显示处理模块、至少设有一个发射通道的谱仪、与谱仪发射通道一一对应连接的至少一个功率放大器、TR开关、前置放大器、多套线圈以及一磁体模块；
所述数据显示处理模块与所述谱仪连接，所述谱仪分别与所述至少一个功率放大器、所述TR开关以及所述前置放大器连接，所述TR开关分别与所述前置放大器以及与目标区域对应的主线圈连接；
所述谱仪包括单通道发射谱仪和/或多通道发射谱仪的任意组合，当组合后的谱仪的发射通道数量不小于线圈数量时，其中一个功率放大器与TR开关连接，其他功率放大器与除主线圈外的其他线圈一一对应连接；当组合后的谱仪的发射通道数量小于线圈数量时，至少一个所述功率放大器的输出端连接有至少一个功分器，至少一个功分器的输出端连接有与线圈数量对应的移相器，此时其中一个移相器或功率放大器与所述TR开关连接，剩余移相器与除主线圈外的其他线圈一一对应连接；
其中，每套线圈产生的射频场和激发区域各不相同，与目标区域对应的主线圈产生的射频场与其他线圈产生的射频场之间的差异大于预设值；
其中，谱仪、功率放大器、TR开关、前置放大器、多套线圈、功分器、移相器和磁体模 块共同组成了RF射频模块。
其中，需要说明的是，每一线圈产生的射频场大小和激发区域可以在线圈设计时根据需求设计相应的绕法、形状、摆放位置和/或线圈上的匹配和调谐电容等，从而达到每套线圈产生的射频场和激发区域各不相同，与目标区域对应的主线圈产生的射频场与其他线圈产生的射频场之间的差异大于预设值的效果。
其中，需要说明的是，所述数据处理显示模块用于发送指令控制射频脉冲序列并接收磁共振信号，以完成实时数据处理；所述谱仪用于控制射频脉冲序列并接收磁共振信号；每一功率放大器的输入端连接谱仪的其中一个发射通道，用于放大谱仪输出的射频脉冲；所述TR开关用于控制目标区域对应的主线圈所在链路的收发转换；所述前置放大器用于放大接收到的磁共振信号；所述磁体模块用于产生静态磁场B0；所述多套射频线圈***用于产生多个与静态磁场B0垂直的射频场B1。
其中，需要说明的是，本申请实施例中的谱仪、功率放大器、功分器和移相器的组合方式具有多种，包括但不限于当组合后的谱仪的发射通道数量不小于线圈数量时，仅设置与发射通道一一对应连接的多个功率放大器，或者是当组合后的谱仪的发射通道数量小于线圈数量时，通过设置功率放大器、功分器和移相器的组合来实现射频脉冲的分功率和相位调整，例如单个发射通道的谱仪对应的单个功率放大器和多个功分器、移相器和多套线圈；多个发射通道的谱仪对应的多个功率放大器和多个功分器、移相器和多套线圈；多个谱仪、多个功率放大器和功分器的灵活组合等等，此处不再一一赘述。
如图1所示，在一种具体的实施方式中，所述磁共振***包括多个单通道发射谱仪或至少一个多通道发射谱仪，还包括与每一发射通道一一对应连接的多个功率放大器，其中一个功率放大器的输出端与所述TR开关连接，其他功率放大器与除主线圈外的其他线圈一一对应连接。
例如，整个***包括一个数据处理显示模块，用于与谱仪连接，发送指令控制射频脉冲序列并接收磁共振信号完成实时数据处理；多台单通道发射谱仪或一台多通道发射磁共振谱仪，用于控制射频脉冲序列并接收磁共振信号；多台功率放大器，输入端连接谱仪的多个发射通道，输出端连接TR开关或多个射频线圈，用于放大谱仪输出的射频脉冲；一个TR开关，用于控制目标区域对应线圈所在链路的收发转换；一个前置放大器，用于放大接收到的磁共振信号；一 个磁体模块,用于产生静态磁场B0；多套射频线圈***，用于产生多个与静态磁场B0垂直的射频场B1。
如图2所示，在一种具体的实施方式中，所述磁共振***包括一个单通道发射谱仪或者仅一个发射通道工作的多通道发射谱仪，还包括一个与该发射通道连接的功率放大器，功率放大器的输出端与一功分器的输入端连接，功分器的输出端与多个移相器连接，其中一个移相器所述TR开关连接，剩余移相器与除主线圈外的其他线圈一一对应连接。
例如：整个***包括一个数据处理显示模块，用于与谱仪连接，发送指令控制射频脉冲序列并接收磁共振信号完成实时数据处理；一台单通道发射磁共振谱仪或一台仅一个发射通道工作的多通道发射谱仪，用于控制射频脉冲序列并接收磁共振信号；一台功率放大器，输入端连接谱仪的一个发射通道，输出端连接多路功分器的输入，用于放大谱仪输出的射频脉冲，需要说明的是，通常仅设有一个功率放大器的***所用的功率放大器输出功率很高才能满足***需求；一个功分器，用于将一路输入射频脉冲的射频功率分成多路；多个移相器，用于调整功分器输出各路的射频脉冲相位；一个TR开关，用于控制目标区域对应线圈所在链路的收发转换；一个前置放大器，用于放大接收到的磁共振信号；一个磁体模块,用于产生静态磁场B0；多套射频线圈***，用于产生多个与静态磁场B0垂直的射频场B1。
如图3所示，在一种具体的实施方式中，所述磁共振***多个单通道发射谱仪或至少一个多通道发射谱仪，优选的，包括两个单通道发射谱仪或仅两个通道工作的一个多通道发射谱仪，还包括与每一发射通道一一对应连接的多个功率放大器，其中一个功率放大器的输出端与所述TR开关连接，其他功率放大器与一功分器连接，功分器的输出端与多个移相器连接，每一移相器与除主线圈外的其他线圈一一对应连接。
例如，整个***包括一个数据处理显示模块，用于与谱仪连接，发送指令控制射频脉冲序列并接收磁共振信号完成实时数据处理；多个单通道发射谱仪或一台多通道发射磁共振谱仪，用于控制射频脉冲序列并接收磁共振信号；多台功率放大器，其中一个功率放大器的输出端与所述TR开关连接，其他功率放大器与一功分器连接，当然可以理解的是，也可以是其中一个功率放大器的输出端与所述TR开关连接，其他功率放大器中的一部分直接与射频线圈相连，另一部分功率放大器后接功分器和移相器再与射频线圈相连，用于放大谱仪输出的射频脉冲； 多个功分器，用于将输入射频脉冲的射频功率分成多路，多个移相器，用于调整功分器输出各路的射频脉冲相位；一个TR开关，用于控制目标区域对应线圈所在链路的收发转换；一个前置放大器，用于放大接收到的磁共振信号；一个磁体模块,用于产生静态磁场B0；多套射频线圈***，用于产生多个与静态磁场B0垂直的射频场B1。
如图4所示，在一种具体的实施方式中，所述磁共振***包括多个单通道发射谱仪或至少一个多通道发射谱仪，优选的，包括两个单通道发射谱仪或仅两个发射通道工作的一个多通道发射谱仪，还包括多个功率放大器，每一功率放大器的输出端连接有一功分器，每一功分器的输出端连接有多个移相器，其中一个移相器与TR开关连接，剩余移相器与除主线圈外的其他线圈一一对应连接。
例如：整个***包括一个数据处理显示模块，用于与谱仪连接，发送指令控制射频脉冲序列并接收磁共振信号完成实时数据处理；多个单通道发射谱仪或一台多通道发射磁共振谱仪，用于控制射频脉冲序列并接收磁共振信号；多台功率放大器，每个功率放大器后都接功分器和移相器再与射频线圈相连，用于放大谱仪输出的射频脉冲；多个功分器，用于将输入射频脉冲的射频功率分成多路；多个移相器，用于调整功分器输出各路的射频脉冲相位；一个TR开关，用于控制目标区域对应线圈所在链路的收发转换；一个前置放大器，用于放大接收到的磁共振信号；一个磁体模块,用于产生静态磁场B0；多套射频线圈***，用于产生多个与静态磁场B0垂直的射频场B1。
如图5所示，在一种具体的实施方式中，本申请实施例中的每种磁共振射频***均包含多套射频线圈，每套射频线圈产生的射频场和激发区域都各不相同，多套射频线圈同时激发，可以达到空间选择的目的。例如图中所示，1、2、3、4分别表示四套不同的射频线圈，其中，1是主线圈，对应着5、6、7、8四个不同的激发区域，9为检测的目标组织区域，10为目标区域周围的其他组织。
在核磁共振中，在射频场B1的作用下，自旋形成的宏观磁化矢量绕着射频场B1旋转，用一定翻转角(即射频功率)的射频脉冲将自旋产生的宏观磁化矢量扳转90度时，得到最大的横向磁化矢量，横向磁化矢量即磁共振信号，所以信号大小与射频场B1以及对应的射频脉冲翻转角密切相关。如果只用图中的主线圈1激发，采集到的磁共振信号除了目标组织区域9 之外必然包含周围组织10的信号，这会导致检测的准确性降低。基于此，本实施例基于上述公开的磁共振***，提出该***的工作方法，以实现目标区域的空间选择。
如图6-9所示，本申请实施例第二方面提供一种如第一方面任意一种可能的设计中所述的具有空间选择性的磁共振***的工作方法，包括但不限于由步骤S1-S3实现：
步骤S1.通过数据处理显示模块向谱仪发送第一指令；
步骤S2.通过谱仪根据第一指令通过多个功率放大器控制多套线圈同时发射主脉冲序列，或依次通过功率放大器、功分器和移相器控制多套线圈同时发射主脉冲序列，以便第一区域的射频场与目标区域的射频场之间的差异大于阈值，其中，第一区域为主线圈的激发区域和其他线圈的激发区域之间的重叠区域；
结合图4和图6所示，当多套线圈同时发射时，将合成一个具有空间选择性的射频场。通过谱仪不同发射通道控制发射信号的幅度和相位，或通过移相器控制相位，使得主线圈1和其他线圈重叠区域的射频场与目标区域的射频场差异较大，从而实现空间激发选择性。例如，用线圈1、2、3、4同时激发，当线圈1的激发区域内自旋产生的宏观磁化矢量被扳转到90度，因为2、3、4三个线圈产生的射频场与线圈1产生的射频场差异较大，所以2、3、4三个线圈的激发区域内自旋产生的宏观磁化矢量未被扳转到90度或者远超过90度，呈现低信号，线圈1激发区域内除去与2、3、4三个线圈激发区域重叠的区域之外(即目标区域)呈现高信号，也就是目标组织区域呈现高信号，从而达到空间选择的目的。
如图6所示，具体的，线圈1到线圈n同时发射主脉冲序列，主脉冲序列为能激发磁共振信号的任何射频脉冲，包括但不限于CPMG脉冲序列。在核磁共振中，在射频场B1的作用下，自旋形成的宏观磁化矢量绕着射频场B1旋转，用一定翻转角的射频脉冲将自旋产生的宏观磁化矢量扳转90度时，得到最大的横向磁化矢量。为了达到空间选择的目的，在设计时使线圈1产生的射频场B1和线圈2-n产生的射频场B1有较大差异，所有线圈都用同一翻转角的射频脉冲激发，射频脉冲翻转角满足线圈1产生的射频场B1对应的翻转角，即线圈1激发区域内呈现高信号，线圈2-n激发区域内呈现低信号，感兴趣的目标区域为线圈1激发区域内除去其他线圈2～n的激发区域，接收线圈1激发区域内的磁共振信号，线圈1激发区域内除去其他线圈2～n的激发区域呈现高信号，线圈1激发区域内与其他线圈2～n的激发区域重叠区域呈现低 信号，从而实现空间选择的效果。
如图7所示，在一种具体的实施方式中，为了实现更优的空间选择效果，在通过谱仪根据第一指令通过多个功率放大器控制多套线圈同时发射主脉冲序列之前，所述工作方法还包括：
通过数据显示模块向谱仪发送第二指令，以便谱仪根据第二指令通过多个功率放大器控制除主线圈外的其他线圈同时发射相同的第一饱和脉冲，或依次通过功率放大器、功分器和移相器控制除主线圈外的其他线圈同时发射相同的第一饱和脉冲；
其中，所述第一饱和脉冲的相位和幅值均可调，以最大限度饱和其他线圈的激发区域内的磁共振信号。
具体的，线圈2-n先同时发射同一饱和脉冲，然后所有线圈发射同一翻转角的射频脉冲主脉冲序列，射频脉冲翻转角满足线圈1产生的射频场B1对应的翻转角，即线圈1激发区域内呈现高信号，线圈2-n激发区域内呈现无信号，感兴趣的目标区域为线圈1激发区域内除去其他线圈2～n的激发区域，接收线圈1激发区域内的磁共振信号，线圈1激发区域内除去其他线圈2～n的激发区域呈现高信号，线圈1激发区域内与其他线圈2～n的激发区域重叠区域呈现无信号，从而实现空间选择的效果。
如图8所示，在一种具体的实施方式中，为了进一步实现更优的空间选择效果，在通过谱仪根据第一指令通过多个功率放大器控制多套线圈同时发射主脉冲序列之前，所述工作方法还包括：
通过数据显示模块向谱仪发送第三指令，以便谱仪根据第三指令通过多个功率放大器控制除主线圈外的其他线圈发射不同的第二饱和脉冲，或依次通过功率放大器、功分器和移相器控制除主线圈外的其他线圈发射不同的第二饱和脉冲。
具体的，线圈2-n中每个线圈都可根据实际情况选择不同的饱和脉冲，可以是不同的翻转角，不同的形状，然后所有线圈发射同一翻转角的射频脉冲主脉冲序列，射频脉冲翻转角满足线圈1产生的射频场B1对应的翻转角，即线圈1激发区域内呈现高信号，线圈2-n激发区域内呈现无信号，感兴趣的目标区域为线圈1激发区域内除去其他线圈2～n的激发区域，接收线圈1激发区域内的磁共振信号，线圈1激发区域内除去其他线圈2～n的激发区域呈现高信号， 线圈1激发区域内与其他线圈2～n的激发区域重叠区域呈现无信号，从而实现空间选择的效果。
步骤S3.将主线圈激发区域产生的磁共振信号依次通过TR开关、前置放大器和谱仪返回至数据处理显示模块，实现目标区域磁共振信号的空间选择。
基于上述公开的内容，本申请实施例通过将磁共振射频***设置为包括单通道发射谱仪和/或多通道发射谱仪的任意组合，对应设置多个功率放大器或者功率放大器、功分器和移相器的组合，同时设置包含主线圈和其他线圈的多套线圈，每套线圈产生的射频场和激发区域各不相同，与目标区域对应的主线圈产生的射频场与其他线圈产生的射频场之间的差异大于预设值；从而***在工作时，可根据待选择的目标区域的需求，由谱仪控制多个功率放大器向多套线圈同时发射主脉冲序列来进行激发，或依次控制功率放大器、功分器和移相器向多套线圈同时发射主脉冲序列来进行激发，从而使得各个不相同的射频场和激发区域在同一翻转角下获得的磁共振信号强度具有较大差异，进而实现目标区域磁共振信号的空间选择，提高磁共振信号检测的准确性，整个过程无需梯度***的支持，降低了磁共振检测的成本和复杂度。
验证例
为了验证本申请实施例所提出的磁共振***及其工作方法具有空间选择性，本申请提出了一种实验例来对该***及其工作方法的可行性进行说明，具体如下：
如图10所示，包括一套具有空间选择性的磁共振***的磁体模块、线圈模块和测量模体相对位置示意图，其中1为主线圈，激发区域比较大，激发深度8cm,线圈2，3，4激发区域比较小，激发深度3.5cm,放在磁体5上，在线圈表面放3cm厚的长方体油模6，以及放直径为8cm,高为12cm的圆柱形油模7。
具体的，本验证例采用图4所示的双通道发射谱仪、两个功率放大器以及两个二路功分器的***，主脉冲序列选择测信噪比的CPMG序列，先后进行以下实验：
实验1：所有线圈同时发射主脉冲序列。
只放浅层油垫子，测得信噪比为4；
在浅层油垫子上增加深层油模，测得信噪比为14；
撤去浅层油垫子，换成相同厚度的干木板，深层油垫子保持原来空间位置不变，测得信噪比为14。
实验2：线圈2，3，4同时发射同一饱和脉冲，然后所有线圈同时发射主脉冲序列。
只放浅层油垫子，测得信噪比为2；
在浅层油垫子上增加深层油模，测得信噪比为16；
撤去浅层油垫子，换成相同厚度的干木板，深层油垫子保持原来空间位置不变，测得信噪比为16。
实验3：线圈2，3，4不同时发射不同的饱和脉冲，然后所有线圈同时发射主脉冲序列。
只放浅层油垫子，测得信噪比为0.8；
在浅层油垫子上增加深层油模，测得信噪比为16；
撤去浅层油垫子，换成相同厚度的干木板，深层油垫子保持原来空间位置不变，测得信噪比为16。
由实验1-3的结果可以看出，只放浅层油模信噪比很低，证明浅层油模所在区域磁共振信号很低，而深层油模加不加浅层油模信噪比基本没变，可以说明主线圈1激发区域内除去其他线圈激发区域外的区域基本不受影响，因此可以说明本申请实施例提出的***和工作方法具有很好的空间选择性。
最后应说明的是：以上所述仅为本发明的优选实施例而已，并不用于限制本发明的保护范围。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种具有空间选择性的磁共振***，其特征在于，包括：数据显示处理模块、至少设有一个发射通道的谱仪、与谱仪的发射通道一一对应连接的至少一个功率放大器、TR开关、前置放大器、多套线圈以及一磁体模块；
    所述数据显示处理模块与所述谱仪连接，所述谱仪分别与所述至少一个功率放大器、所述TR开关以及所述前置放大器连接，所述TR开关分别与所述前置放大器以及与目标区域对应的主线圈连接；
    所述谱仪包括单通道发射谱仪和/或多通道发射谱仪的任意组合，当组合后的谱仪的发射通道数量不小于线圈数量时，其中一个功率放大器与TR开关连接，其他功率放大器与除主线圈外的其他线圈一一对应连接；当组合后的谱仪的发射通道数量小于线圈数量时，至少一个所述功率放大器的输出端连接有至少一个功分器，至少一个功分器的输出端连接有与线圈数量对应的移相器，此时其中一个移相器或功率放大器与所述TR开关连接，剩余移相器与除主线圈外的其他线圈一一对应连接；
    其中，每套线圈产生的射频场和激发区域各不相同，与目标区域对应的主线圈产生的射频场与其他线圈产生的射频场之间的差异大于预设值。
  2. 根据权利要求1所述的具有空间选择性的磁共振***，其特征在于，包括多个单通道发射谱仪或至少一个多通道发射谱仪，还包括与每一发射通道一一对应连接的多个功率放大器，其中一个功率放大器的输出端与所述TR开关连接，其他功率放大器与除主线圈外的其他线圈一一对应连接。
  3. 根据权利要求1所述的具有空间选择性的磁共振***，其特征在于，包括一个单通道发射谱仪或者仅一个发射通道工作的多通道发射谱仪，还包括一个与该发射通道连接的功率放大器，功率放大器的输出端与一功分器的输入端连接，功分器的输出端与多个移相器连接，其中一个移相器所述TR开关连接，剩余移相器与除主线圈外的其他线圈一一对应连接。
  4. 根据权利要求1所述的具有空间选择性的磁共振***，其特征在于，包括多个单通道发射谱仪或至少一个多通道发射谱仪，还包括与每一发射通道一一对应连接的多个功率放大器，其中一个功率放大器的输出端与所述TR开关连接，其他功率放大器与一功分器连接，功分器 的输出端与多个移相器连接，每一移相器与除主线圈外的其他线圈一一对应连接。
  5. 根据权利要求1所述的具有空间选择性的磁共振***，其特征在于，包括多个单通道发射谱仪或至少一个多通道发射谱仪，还包括多个功率放大器，每一功率放大器的输出端连接有一功分器，每一功分器的输出端连接有多个移相器，其中一个移相器与TR开关连接，剩余移相器与除主线圈外的其他线圈一一对应连接。
  6. 根据权利要求4或5所述的具有空间选择性的磁共振***，其特征在于，包括两个单通道发射谱仪或仅两个发射通道工作的一个多通道发射谱仪，每一发射通道的输出端连接有一个功率放大器。
  7. 根据权利要求1-6任意一项所述的具有空间选择性的磁共振***的工作方法，其特征在于，包括：
    通过数据处理显示模块向谱仪发送第一指令；
    通过谱仪根据第一指令通过多个功率放大器控制多套线圈同时发射主脉冲序列，或依次通过功率放大器、功分器和移相器控制多套线圈同时发射主脉冲序列，以便第一区域的射频场与目标区域的射频场之间的差异大于阈值，其中，第一区域为主线圈的激发区域和其他线圈的激发区域之间的重叠区域；
    将主线圈激发区域产生的磁共振信号依次通过TR开关、前置放大器和谱仪返回至数据处理显示模块，实现目标区域磁共振信号的空间选择。
  8. 根据权利要求7所述的工作方法，其特征在于，在通过谱仪根据第一指令通过多个功率放大器控制多套线圈同时发射主脉冲序列之前，所述工作方法还包括：
    通过数据显示模块向谱仪发送第二指令，以便谱仪根据第二指令通过多个功率放大器控制除主线圈外的其他线圈同时发射相同的第一饱和脉冲，或依次通过功率放大器、功分器和移相器控制除主线圈外的其他线圈同时发射相同的第一饱和脉冲；
    其中，所述第一饱和脉冲的相位和幅值均可调，以最大限度饱和其他线圈的激发区域内的磁共振信号。
  9. 根据权利要求7所述的工作方法，其特征在于，在通过谱仪根据第一指令通过多个功率放大器控制多套线圈同时发射主脉冲序列之前，所述工作方法还包括：
    通过数据显示模块向谱仪发送第三指令，以便谱仪根据第三指令通过多个功率放大器控制除主线圈外的其他线圈发射不同的第二饱和脉冲，或依次通过功率放大器、功分器和移相器控制除主线圈外的其他线圈发射不同的第二饱和脉冲。
  10. 根据权利要求7所述的工作方法，其特征在于，所述主脉冲序列包括CPMG序列。
PCT/CN2022/130123 2022-10-09 2022-11-04 一种具有空间选择性的磁共振***及其工作方法 WO2024077687A1 (zh)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080167548A1 (en) * 2007-01-04 2008-07-10 Sorensen Alma G Tissue Alteration With MRI RF Field
CN101598775A (zh) * 2009-06-19 2009-12-09 沈阳工业大学 医用磁共振成像仪单边磁体装置
CN108827996A (zh) * 2018-04-13 2018-11-16 王黎莉 一种单边核磁共振弹性成像检测装置
CN114062412A (zh) * 2021-11-16 2022-02-18 国网重庆市电力公司电力科学研究院 产生梯度磁场的手持式单边无损检测磁共振传感器结构
CN114720926A (zh) * 2021-03-31 2022-07-08 无锡鸣石峻致医疗科技有限公司 一种器官无创定量核磁共振检测***
CN114720927A (zh) * 2021-03-31 2022-07-08 无锡鸣石峻致医疗科技有限公司 一种适用于器官无创定量检测的核磁共振测量***

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080167548A1 (en) * 2007-01-04 2008-07-10 Sorensen Alma G Tissue Alteration With MRI RF Field
CN101598775A (zh) * 2009-06-19 2009-12-09 沈阳工业大学 医用磁共振成像仪单边磁体装置
CN108827996A (zh) * 2018-04-13 2018-11-16 王黎莉 一种单边核磁共振弹性成像检测装置
CN114720926A (zh) * 2021-03-31 2022-07-08 无锡鸣石峻致医疗科技有限公司 一种器官无创定量核磁共振检测***
CN114720927A (zh) * 2021-03-31 2022-07-08 无锡鸣石峻致医疗科技有限公司 一种适用于器官无创定量检测的核磁共振测量***
CN114062412A (zh) * 2021-11-16 2022-02-18 国网重庆市电力公司电力科学研究院 产生梯度磁场的手持式单边无损检测磁共振传感器结构

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