CN217718070U - Magnetic resonance signal receiving device and magnetic resonance imaging equipment - Google Patents
Magnetic resonance signal receiving device and magnetic resonance imaging equipment Download PDFInfo
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Abstract
The application provides a magnetic resonance signal receiving arrangement and magnetic resonance imaging equipment includes: the radio frequency power amplifier receives and amplifies the magnetic resonance signal; the adjustable band-pass filter receives and filters the magnetic resonance signal, and sends the filtered signal to the analog-to-digital converter; the analog-to-digital converter converts the filtered magnetic resonance signals into digital signals; the adjusting module receives the first control signal and adjusts the first control signal; the low-pass filter filters the adjusted first control signal to prevent the radio-frequency pulse from flowing backwards to enter the adjusting module to burn the receiving device; the first control module is used for controlling the radio frequency power amplifier, the adjustable band-pass filter, the analog-to-digital converter and the adjusting module. The center frequency of the adjustable band-pass filter is controlled through the second control signal, so that the adjustable band-pass filter is compatible with receiving coils corresponding to different nuclides, and the adjustable band-pass filter is simple in circuit structure, low in cost, reusable, high in flexibility, strong in compatibility and easy to miniaturize.
Description
Technical Field
The application relates to the technical field of nuclear magnetic resonance instruments, in particular to a magnetic resonance signal receiving device and magnetic resonance imaging equipment.
Background
Nuclear magnetic resonanceThe imaging technology is a medical imaging technology which utilizes a magnetic field and radio frequency pulses to carry out operations such as excitation, coding, receiving, image reconstruction and the like on atomic nuclei, and finally obtains an image of an internal structure of an object. At present, utilize1The way in which spins of H nuclei are imaged is most mature clinically, however1Nuclides other than H have unique effects in the human body, affecting a variety of tissues and organs, such as13C、19F、23Na、129Xe, and the like. Different nuclides are imaged to carry out different medical applications, such as observing metabolic processes, detecting cavities, researching organs, treating diseases and the like, and the method has wide medical research and clinical application prospects.
The single nuclear magnetic resonance imaging equipment only needs to be paired1H atomic nucleus is imaged, and in order to inhibit image frequency and increase signal-to-noise ratio, the H atomic nucleus is imaged in a signal receiving device of equipment1The Larmor precession frequency of H atomic nucleus is band-pass frequency-selected, and the structural information inside the object can be contained in the radio frequency signal with the bandwidth of about 1 MHz. Different nuclides have different larmor precession frequencies, and one receiving device can only band-pass select a larmor precession frequency. Therefore, for a magnetic resonance imaging receiving device for detecting multiple nuclear species, each nuclear species needs to correspond to one receiving device, and the multiple receiving devices cause great redundancy of circuits, higher cost and waste.
In the prior art, the same circuit architecture can be used for realizing the acquisition of magnetic resonance signals of different nuclides, but the circuit composition is complex, complex operations such as power division and demodulation are needed, wiring is complex, and the cost is high.
SUMMERY OF THE UTILITY MODEL
Based on the defects of the prior art, the application provides a magnetic resonance signal receiving device and a magnetic resonance imaging device, so that the problems of complex components and complex wiring of the existing multi-core magnetic resonance signal receiving circuit are at least solved.
In a first aspect, the present application provides a magnetic resonance signal receiving apparatus for receiving magnetic resonance signals of different nuclear species, including: a tunable bandpass filter for receiving and filtering magnetic resonance signals, at least a portion of which are generated by excitation of a plurality of specific nuclear species; the analog-to-digital converter is connected with the adjustable band-pass filter and used for converting the filtered magnetic resonance signals into digital signals; the adjusting module is used for receiving a first control signal and adjusting the first control signal; the input end of the low-pass filter is connected with the adjusting module and used for filtering the adjusted first control signal; and the first control module is connected with the adjustable band-pass filter, the analog-to-digital converter and the adjusting module and is used for sending a first control signal to the adjusting module, and/or sending a second control signal for controlling the adjustable band-pass filter, and/or sending a third control signal for controlling the analog-to-digital converter.
In an embodiment, the tunable bandpass filter comprises a chip element and/or a filter device built with a discrete device.
In an embodiment, the filter device includes at least one inductor and at least one capacitance-adjustable component, the at least one inductor and the at least one capacitance-adjustable component are connected to form a filter circuit, and the capacitance-adjustable component is further connected to the first control module.
In one embodiment, the filter device comprises a first inductor, a second inductor, a first capacitance value adjustable component and a second capacitance value adjustable component; one end of the first inductor receives a magnetic resonance signal, and the other end of the first inductor is grounded; the first end of the first capacitance value adjustable component receives a magnetic resonance signal, the second end of the first capacitance value adjustable component is grounded, and the control end of the first capacitance value adjustable component is connected with the first control module; one end of the second inductor receives a magnetic resonance signal, the other end of the second inductor is connected with a second capacitance value adjustable component in series, the second capacitance value adjustable component outputs the filtered magnetic resonance signal, and the control end of the second capacitance value adjustable component is connected with the first control module.
In an embodiment, the filter device further includes a third inductor and a third capacitance-adjustable component; one end of the third inductor is connected with the output end of the second capacitance value adjustable component, and the other end of the third inductor is grounded; the first end of the third capacitance value adjustable component is connected with the output end of the second capacitance value adjustable component, the second end of the third capacitance value adjustable component is grounded, and the control end of the third capacitance value adjustable component is connected with the first control module.
In one embodiment, the tunable band-pass filter is any one of an active band-pass filter, a chebyshev filter, a butterworth filter, an elliptic filter, and a bessel filter.
In one embodiment, the capacitance-adjustable component includes: the circuit comprises at least two first capacitors connected in series and/or at least two second capacitors connected in parallel, wherein the first capacitors are respectively connected with a first switch in parallel, the second capacitors are respectively connected with a second switch in series, and the control ends of the first switches and the second switches are respectively connected with a first control module;
the first capacitor comprises a capacitor with a fixed capacitance value or an adjustable capacitance value, and the second capacitor comprises a capacitor with a fixed capacitance value or an adjustable capacitance value.
In one embodiment, the magnetic resonance signal receiving apparatus further includes: the input end of the radio frequency power amplifier receives a magnetic resonance signal, the output end of the radio frequency power amplifier is connected with the adjustable band-pass filter, and the control end of the radio frequency power amplifier is connected with the first control module and used for receiving and amplifying the magnetic resonance signal; and the first control module sends a fourth control signal for controlling the radio frequency power amplifier to the radio frequency power amplifier.
In a second aspect, the present application proposes a magnetic resonance imaging apparatus comprising at least one magnetic resonance signal receiving device as described in the first aspect, further comprising:
a scanner for generating a main magnetic field and capable of exciting nuclear spins of a plurality of specific nuclear species of an examination object in the main magnetic field to generate magnetic resonance signals; a receiving coil connected with the scanner to receive the magnetic resonance signal, the receiving coil being connected with a magnetic resonance signal receiving device; and the data processing module is used for receiving the digital signals and generating a magnetic resonance image.
In an embodiment, the magnetic resonance imaging apparatus further includes a second control module, connected to the magnetic resonance signal receiving device, for controlling the first control module to send the first control signal, the second control signal, the third control signal, and the fourth control signal.
In an embodiment, the magnetic resonance imaging apparatus comprises at least two of said magnetic resonance signal receiving devices, at least two of said scanners and at least two of said receiving coils; the scanners respectively generate magnetic resonance signals of specific nuclides, and the magnetic resonance signal receiving device simultaneously receives corresponding magnetic resonance signals.
Compared with the prior art, the method has the advantages that the first control module sends the first control signal for adjusting the receiving coil to be in the detuning state or the resonance state to the adjusting module, so that the state of the receiving coil is changed, and the receiving device is prevented from being burnt by the stronger radio-frequency pulse when the scanner emits the radio-frequency pulse to excite the nuclear spin of the specific nuclide; the first control module sends a second control signal for controlling the center frequency of the tunable band-pass filter to the tunable band-pass filter according to the corresponding nuclide to be detected, so that the tunable band-pass filter can be compatible with receiving coils corresponding to different nuclides, circuit redundancy is avoided, and complicated processes such as power division and frequency conversion are not needed; the first control module sends a third control signal for controlling the sampling frequency of the analog-to-digital converter to the analog-to-digital converter so as to adjust the sampling frequency according to requirements; and filtering the adjusted first control signal through a low-pass filter to prevent the radio-frequency pulse from flowing backwards to enter an adjusting module to burn the receiving device. The center frequency of the adjustable band-pass filter is controlled through the second control signal, so that the receiving coils corresponding to different nuclides are compatible, and the circuit is simple in structure, low in cost, reusable, high in flexibility, strong in compatibility and easy to miniaturize.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without undue limitation to the invention.
Fig. 1 is a schematic diagram of a connection of modules of a magnetic resonance signal receiving apparatus according to an embodiment of the present application.
Fig. 2 is a circuit diagram of a filter device in an example embodiment of the present application.
Fig. 3 is a circuit diagram of a filter device in another example embodiment of the present application.
Fig. 4 is a circuit diagram of a capacitance adjustable component according to an embodiment of the present application.
Fig. 5 is a schematic diagram of a module connection of a magnetic resonance signal receiving apparatus according to another exemplary embodiment of the present application.
FIG. 6 shows the center frequency of 59.302MHz (in example 1: (B))129Xe nuclei).
FIG. 7 shows the center frequency of 32.678MHz (C.) (in example 32H-kernel) is generated.
FIG. 8 shows the center frequency of 53.542MHz (C) ((R))13C-kernel) is used.
FIG. 9 shows the center frequency of 86.257MHz (C) in example 331P-kernel) is used.
Fig. 10 is a schematic diagram of a module connection of an mri apparatus according to an embodiment of the present application.
Fig. 11 is a schematic diagram of a module connection of a magnetic resonance imaging apparatus according to another embodiment of the present application.
Detailed Description
The present application will be described in further detail below with reference to examples in order to facilitate understanding and implementation of the present application by those of ordinary skill in the art, and it should be understood that the implementation examples described herein are only for illustration and explanation of the present application and are not intended to limit the present application.
It is obvious that the drawings in the following description are only examples or embodiments of the present application, and that it is also possible for a person skilled in the art to apply the present application to other similar contexts on the basis of these drawings without inventive effort. Moreover, it should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another.
Referring to fig. 1, fig. 1 is a schematic diagram of a module connection of a magnetic resonance signal receiving apparatus according to the present application.
In one embodiment, the present application provides a magnetic resonance signal receiving apparatus 10, including: a tunable band-pass filter 101, an analog-to-digital converter 102, an adjustment module 103, a low-pass filter 104, and a first control module 105. Wherein: a tunable bandpass filter 101 for receiving and filtering magnetic resonance signals, at least a portion of which are generated by excitation of a plurality of specific nuclear species; an analog-to-digital converter 102 connected to the tunable band-pass filter 101 for converting the filtered magnetic resonance signal into a digital signal; the adjusting module 103 is configured to receive the first control signal and adjust the first control signal; a low pass filter 104, an input end of which is connected to the adjusting module 103, for filtering the adjusted first control signal to prevent the rf pulse from flowing backward into the adjusting module 103 to burn the receiving device; a first control module 105, connected to the tunable bandpass filter 101, the analog-to-digital converter 102 and the adjusting module 103, for sending a first control signal to the adjusting module 103, and/or sending a second control signal for controlling the tunable bandpass filter 101, and/or sending a third control signal for controlling the analog-to-digital converter 102.
In this embodiment, the first control module 105 sends a first control signal to the adjusting module 103 for adjusting the receiving coil 30 to be in a detuned state or a resonant state, so as to change the state of the receiving coil, thereby preventing the receiving device from being burnt by a stronger radio-frequency pulse when the scanner 20 emits the radio-frequency pulse to excite nuclear spins of a specific nuclear species; the first control module 105 sends a second control signal for controlling the center frequency of the tunable band-pass filter 101 to the tunable band-pass filter 101 according to the corresponding nuclide to be detected, so that the receiving coils 30 corresponding to different nuclides can be compatible, the circuit structure is simple, no circuit redundancy exists, and complicated processes such as power division and frequency conversion are not needed; the first control module 105 sends a third control signal for controlling the sampling frequency of the analog-to-digital converter 102 to the analog-to-digital converter 102, so as to adjust the sampling frequency according to requirements; filtering the adjusted first control signal through a low-pass filter 104 to prevent the radio-frequency pulse from flowing backward to enter an adjusting module 103 to burn the receiving device; the tunable bandpass filter 101 is a device with a tunable center frequency that allows waves in a particular frequency band to pass while shielding other frequency bands. According to the larmor frequency of the nuclide to be detected, the center frequency of the adjustable band-pass filter 101 is adjusted, and band-pass filtering is performed on the signal sent by the receiving coil. The tunable bandpass filter 101 is compatible with receive coils corresponding to different nuclides, and has good flexibility.
The center frequency of the adjustable band-pass filter 101 is larmor frequency ω of a corresponding nuclide to be measured, and ω = γ B according to a formula, where γ is a gyromagnetic ratio of the corresponding nuclide, and B is magnetic induction intensity of the magnetic resonance device. Corresponding nuclides include, but are not limited to1H、2H、3He、7Li、13C、15N、17O、19F、23Na、31P、129Xe, corresponding magnetic induction>0.7T。
In one embodiment, the filter device comprises at least one inductor and at least one capacitance value adjustable component, and the at least one inductor and the at least one capacitance value adjustable component are connected to form a filter circuit.
It should be emphasized that the capacitance-adjustable component mentioned herein can be any device or device group that utilizes an electrical signal to control the capacitance, including but not limited to a programmable IC device of a digital control chip type, a micro-motor operated rotary-vane device, a varactor device, or a discrete capacitor group that utilizes a switch device to control a plurality of capacitors in series/parallel to obtain a variable total capacitance, and various combinations of series/parallel connection of the capacitance-adjustable capacitor devices.
In an exemplary embodiment, as shown in fig. 2, the filter device includes a first inductor L1, a second inductor L2, a first capacitance value adjustable component 101a, and a second capacitance value adjustable component 101b. One end of the first inductor L1 receives a magnetic resonance signal, and the other end of the first inductor L1 is grounded; a first end of the first capacitance value adjustable component 101a receives a magnetic resonance signal, a second end of the first capacitance value adjustable component 101a is grounded, and a control end of the first capacitance value adjustable component 101a is connected with the first control module 105; one end of the second inductor L2 receives a magnetic resonance signal, the other end of the second inductor L is connected in series with the second capacitance value adjustable component 101b, the second capacitance value adjustable component 101b outputs a filtered magnetic resonance signal, and a control end of the second capacitance value adjustable component 101b is connected to the first control module 105.
The first inductor L1, the second inductor L2, the first capacitance-adjustable component 101a, and the second capacitance-adjustable component 101b constitute a filter circuit, and the center frequency of the filter circuit is adjusted by adjusting the capacitance of the first capacitance-adjustable component 101a and/or the second capacitance-adjustable component 101b.
In another exemplary embodiment, as shown in fig. 3, the filter device includes a first inductor L1, a second inductor L2, a third inductor L3, a first capacitance value adjustable component 101a, a second capacitance value adjustable component 101b, and a third capacitance value adjustable component 101c. One end of the first inductor L1 receives a magnetic resonance signal, and the other end of the first inductor L1 is grounded; a first end of the first capacitance value adjustable component 101a receives a magnetic resonance signal, a second end of the first capacitance value adjustable component 101a is grounded, and a control end of the first capacitance value adjustable component 101a is connected with the first control module 105; one end of the second inductor L2 receives a magnetic resonance signal, the other end of the second inductor L2 is connected in series with a second capacitance value adjustable component 101b, the second capacitance value adjustable component 101b outputs a filtered magnetic resonance signal, and the control end of a second capacitance value adjustable component C2 is connected with the first control module 105; one end of the third inductor L3 is connected to the output end of the second capacitance value adjustable component 101b, and the other end is grounded; a first end of the third capacitance value adjustable component 101c is connected to the output end of the second capacitance value adjustable component 101b, a second end of the third capacitance value adjustable component 101c is grounded, and a control end of the third capacitance value adjustable component 101c is connected to the first control module 105.
The first inductor L1, the second inductor L2, the third inductor L3, the first capacitance-adjustable component 101a, the second capacitance-adjustable component 101b, and the third capacitance-adjustable component 101c form a filter circuit, and the center frequency of the filter circuit is adjusted by adjusting the capacitance of the first capacitance-adjustable component 101a and/or the second capacitance-adjustable component 101b and/or the third capacitance-adjustable component 101c.
In order to achieve a better filtering effect, the first inductor L1 and the second inductor L2 should be selected to satisfy impedance matching, so as to reduce the attenuation of the magnetic resonance signal in the passband of the tunable bandpass filter 101 as much as possible.
In order to suppress the image frequency, the optimal tunable bandpass filter 101 is a Chebyshev filter with a bandwidth of 1MHz, a loss at the center frequency of 0.1-0.5 dB, and a loss of 30-40 dB outside a deviation of + -5 MHz from the center frequency. The filter is selected from any one of an active band-pass filter, a Butterworth filter, an elliptic filter, a Bessel filter and the like, the bandwidth is preferably less than 20MHz, the loss at the central frequency is less than 10dB, and the loss is more than 20dB outside the range of +/-15 MHz of the central frequency.
In one embodiment, as shown in fig. 4, the capacitance-adjustable component comprises at least two first capacitors Ca connected in seriesi(where i e n represents the number of first capacitors required), and/or at least two second capacitors Cb connected in paralleli(where i ∈ m, m represents the number of second capacitors required), the first capacitors being connected in parallel with first switches Ka, respectivelyi(where i ∈ n, n represents the number of the required first capacitors), and the second capacitors are respectively connected in series with second switches Kbi(where i e m represents the number of second capacitors required), the control terminals of the first switch and the second switch are connected to the first control module 105, respectively.
Wherein the first capacitor CaiComprises a fixed capacitor or a capacitor with adjustable capacitance, a second capacitor CbiIncluding fixed or adjustable capacitance capacitors. The first capacitor Ca can be selected according to actual production requirementsiA second capacitor CbiSpecific model and specification.
The first control module 105 controls the first capacitor CaiParallel first switch KaiAnd a second capacitor CbiSecond switch Kb in seriesiThe opening or closing state of the adjustable component is adjusted, and then the capacity value of the adjustable component is adjusted.
The magnetic resonance signal output after being filtered by the tunable band-pass filter 101 is an analog signal, and the analog-to-digital converter 102 directly samples the analog signal, so that the analog signal is converted into a digital signal and output to the data processing module for image reconstruction.
The first control module 105 outputs a first control signal, which is amplified by the adjusting module 103 and then filtered by the low-pass filter 104 to adjust the adjustable capacitor in the receiving coil, thereby changing the state of the receiving coil.
During the process of emitting radio frequency pulse by the scanner and exciting nuclear spin of nuclide, the receiving coil is configured in a detuned state by the adjusting module 103, so that the receiving device is prevented from being burnt by the stronger radio frequency pulse. During magnetic resonance signal reception, the receive coil is configured to a resonant state by the adjustment module 103.
The low pass filter 104 suppresses the high frequency band signal, and prevents the backward flow of the magnetic resonance signal from entering the adjusting module 103 during the receiving process of the magnetic resonance signal.
The first control module 105 may be a Field Programmable logic device (FPGA), or any electric controller capable of receiving an external control command to complete control operations of the devices.
When the magnetic resonance signal receiving device works, the adjustable band-pass filter 101 receives and filters a magnetic resonance signal, the filtered magnetic resonance signal enters the analog-to-digital converter 102, the analog-to-digital converter 102 performs analog-to-digital conversion on the magnetic resonance signal to obtain a digital signal, and the digital signal is output to the data processing module to perform image reconstruction, so that image information inside an object to be detected can be obtained.
Compared with the prior art, the magnetic resonance signal receiving device is simple in circuit structure, free of circuit redundancy, capable of achieving acquisition of magnetic resonance signals of different nuclides by adopting the mode that the adjustable band-pass filter is used for filtering the magnetic resonance signals and the analog-to-digital converter is used for directly sampling the magnetic resonance signals without complex power division and frequency conversion in the magnetic resonance signal receiving process, and simple in circuit structure, low in cost, reusable, high in flexibility, strong in compatibility and easy to miniaturize.
In an embodiment, as shown in fig. 5, the magnetic resonance signal receiving apparatus further comprises a radio frequency power amplifier 106. The radio frequency power amplifier 106 is used for receiving the magnetic resonance signal at the input end, connecting the output end with the adjustable band-pass filter 101, and connecting the control end with the first control module 105 for receiving and amplifying the magnetic resonance signal;
specifically, the radio frequency power Amplifier 106 (VGA) can amplify the magnetic resonance signal of mA (milliamp level), which is convenient for the subsequent circuit processing.
Specifically, before testing, the first control module 105 sets the gain of the rf power amplifier 106 according to different nuclides to be tested. In the operation of the magnetic resonance signal receiving device, the radio frequency power amplifier 106 receives the magnetic resonance signal, amplifies the magnetic resonance signal and outputs the magnetic resonance signal to the adjustable band-pass filter 101, and the adjustable band-pass filter 101 filters the magnetic resonance signal and outputs the magnetic resonance signal to the analog-to-digital converter 102, so that the maximum value of the signal acquired by the analog-to-digital converter 102 can reach full amplitude.
The first embodiment is as follows:
this example was tested simultaneously at 5T magnetic field1H nucleus and129magnetic resonance images of Xe nuclei. Before testing, corresponding to the test data1H nucleus and129the two sets of receiving coils of the Xe core are connected to two sets of receiving devices as shown in fig. 5, respectively.
The Larmor precession frequencies of the nuclides to be measured are 212.887 MHz: (1H core) and 59.302 MHz: (129Xe nuclei). In this embodiment, aim at1The adjustable band-pass filter 101 corresponding to the H core uses ADMV8052 components, and the second control module sets the pass band of the ADMV8052 components to be 212.28-213.34 MHz through the first control module 105.
129The adjustable band-pass filter 101 corresponding to the Xe core is built by combining an inductance and a capacitance value adjustable component. To ensure that the filter has the best frequency selective characteristics and to suppress image frequencies, the tunable bandpass filter 101 is preferably a chebyshev bandpass filter. This embodiment employs a tunable bandpass filter circuit as shown in fig. 3, wherein the first inductance L1=1nH, the second inductance L2=10 μ H, and the third inductance L3=1nH. The first capacitance value adjustable component 101a and the third capacitance value adjustable component 101c adopt switchesThe device adjusts a capacitance value adjustable component (shown in figure 4) formed by a plurality of discrete series/parallel programmable IC capacitors. The first control module 105 adjusts the capacitance values of the first and third capacitance-value adjustable components 101a and 101c to 7.204nF. The second capacitance adjustable component 101b is a varactor, and the capacitance is adjusted to 720.4fF. Obtain the corresponding129The spectrum of the band-pass filter 101 of the Xe core is as shown in fig. 6, and the center frequency bandwidth of the spectrum is 0.9MHz, which achieves a strong suppression effect on the out-of-band frequencies.
In this embodiment, the sampling frequency of the analog-to-digital converter 102 in both sets of receiving apparatuses is set to 100MHz, and the filtered magnetic resonance signal is subjected to undersampling.
In the working process of the magnetic resonance signal receiving device, the magnetic resonance signal is amplified by the radio frequency power amplifier 106, filtered by the adjustable band-pass filter 101, enters the analog-to-digital converter 102, is converted into a digital signal by using a direct sampling mode, and is output to the data processing module for image reconstruction, so that the image information inside the object to be detected can be obtained, and the completion of the image reconstruction is completed1H nucleus and129simultaneous sampling of Xe nuclei.
Example two:
this example was tested simultaneously at a magnetic field of 9T1H nucleus and23magnetic resonance images of Na nuclei. Before testing, corresponding1H nucleus and23the two sets of receiving coils of the Na core are respectively connected to the two sets of receiving devices shown in fig. 5.
The Larmor precession frequency corresponding to the nuclide to be detected is 383.197 MHz: (1H core) and 101.425 MHz: (23Na core). In this embodiment, point to1The adjustable band-pass filter 101 corresponding to the H-core uses an ADMV8052 component, and the first control module 105 sets the passband of the ADMV8052 component to be 212.28-213.34 MHz. For the purpose of23The adjustable band-pass filter 101 corresponding to the Na core also uses an ADMV8052 component, and the first control module 105 sets the pass band of the AM3090 component to 100.60-102.19 MHz.
In this embodiment, the sampling frequency of the analog-to-digital converter 102 in both sets of receiving apparatuses is set to 100MHz, and the filtered magnetic resonance signal is subjected to undersampling.
In the working process of the magnetic resonance signal receiving device, the magnetic resonance signal is amplified by the radio frequency power amplifier 106, filtered by the adjustable band-pass filter 101, enters the analog-to-digital converter 102, is converted into a digital signal by using a direct sampling mode, and is output to the data processing module for image reconstruction, so that the image information inside the object to be detected can be obtained, and the completion of the image reconstruction is completed1H nucleus and23simultaneous sampling of Na nuclei.
EXAMPLE III：
This example was tested simultaneously at 5T magnetic field2H nucleus,13C core and31magnetic resonance image of P nuclei. Before testing, corresponding to the test data2H nucleus,13C core and31the three sets of receiving coils of the P core are respectively connected to three sets of receiving devices as shown in fig. 5.
The Larmor precession frequency of the nuclide to be detected is 32.678MHz2H nucleus), 53.542 MHz: (13C core) and 86.257 MHz: (31P core). The tunable bandpass filter 101 is built by using discrete devices for all three nuclides, and in order to ensure that the filter has the best frequency selection characteristic and suppresses the image frequency, the chebyshev bandpass filter is preferably used in this embodiment.
In the present embodiment, a tunable bandpass filter circuit as shown in fig. 3 is adopted, and in three bandpass filter circuits, a first inductance L1=1nH, a second inductance L2=10 μ H, and a third inductance L3=1nH.
For the purpose of2And the first control module 105 adjusts the capacitance values of the first capacitance value adjustable component 101a and the third capacitance value adjustable component 101c to 23.72nF for the band-pass filter 101 corresponding to the H-kernel. A4W3HW capacitance value adjustable capacitor driven by a micro motor is used as a second capacitance value adjustable component 101b, the capacitance value of 101b is set to be 2.372pF, and the corresponding capacitance value is obtained2The bandpass filter 101 spectrum for H is shown in fig. 7, with a center frequency bandwidth of 0.5MHz.
To is directed at13And the first control module 105 adjusts the capacitance values of the first capacitance value adjustable component 101a and the third capacitance value adjustable component 101C to 8.837nF for the band-pass filter 101 corresponding to the C kernel. A4W3HW capacity value driven by micro motorThe capacitor is used as a second capacitance value adjustable component 101b, and the capacitance value of 101b is set to be 883.7fF to obtain the corresponding capacitance value13The spectrum of the bandpass filter 101 of C is shown in fig. 8, with a center frequency bandwidth of 0.8MHz.
To is directed at31The first control module 105 adjusts the capacitance of the first capacitance adjustable component 101a and the third capacitance adjustable component 101c to 3.404nF for the band-pass filter 101 corresponding to the P-kernel.
Two A4W3HW capacitance-adjustable capacitors driven by micro motors are connected in series to serve as a second capacitance-adjustable component 101b, and the first control module 105 adjusts the second capacitance-adjustable component 101b to 340.4fF. The spectrum of the resulting bandpass filter 101 is shown in fig. 9, with a center frequency bandwidth of 1.3MHz.
In this embodiment, the sampling frequencies of the analog-to-digital converters 102 in the three sets of receiving apparatuses are all set to 100MHz, and the filtered magnetic resonance signals are undersampled.
In the working process of the magnetic resonance signal receiving device, the magnetic resonance signal is amplified by the radio frequency power amplifier 106, filtered by the adjustable band-pass filter 101, enters the analog-to-digital converter 102, is converted into a digital signal by using a direct sampling mode, and is output to the data processing module for image reconstruction, so that the image information in the object to be detected can be obtained, and the magnetic resonance signal receiving device finishes the operation2H nucleus,13C core and31simultaneous sampling of P cores.
In another aspect, the present application further provides a magnetic resonance imaging apparatus 1, and referring to fig. 10, fig. 10 is a schematic connection diagram of a magnetic resonance imaging apparatus module of the present application, including the magnetic resonance signal receiving device 10 in the above embodiment, and further including: a scanner 20 for generating a main magnetic field and capable of exciting nuclear spins of a plurality of specific nuclear species of an examination object in the main magnetic field to generate magnetic resonance signals; a receiving coil 30 connected to the scanner 20 to receive the magnetic resonance signal, the receiving coil 30 being connected to the magnetic resonance signal receiving apparatus 10; and a data processing module 40 for receiving the digital signals and generating a magnetic resonance image.
Compared with the prior art, the magnetic resonance imaging device is formed based on the magnetic resonance signal receiving device, the whole circuit structure of the magnetic resonance imaging device is simple, circuit redundancy is avoided, processes such as complex power division and frequency conversion are not needed, and simultaneous acquisition and simultaneous imaging of different nuclide magnetic resonance signals can be achieved. And because the magnetic resonance signal receiving device has simple structure and is easy to miniaturize, the position of the receiving coil can be more close to the whole structure of the magnetic resonance imaging equipment, the signal-to-noise ratio of the received signal is improved, and the imaging quality is improved.
In an embodiment, referring to fig. 11, fig. 11 is a block diagram illustrating a connection of the magnetic resonance imaging apparatus including the second control module 50 according to the present application. The magnetic resonance imaging apparatus 1 further comprises a second control module 50 connected to the magnetic resonance signal receiving device 10, for controlling the first control module 105 to send the first control signal, the second control signal, the third control signal, and the fourth control signal.
In an embodiment, the magnetic resonance imaging apparatus 1 comprises at least two magnetic resonance signal receiving devices 10, at least two scanners 20, and at least two receiving coils 30; the scanner 20 generates magnetic resonance signals of specific nuclear species, and the magnetic resonance signal receiving apparatus 10 simultaneously receives the corresponding magnetic resonance signals.
The multi-core simultaneous imaging is realized by using at least two magnetic resonance signal receiving devices according to the requirement, and the following two modes can be specifically adopted: the scanner respectively generates magnetic resonance signals of specific nuclides, and the magnetic resonance signal receiving device simultaneously acquires the magnetic resonance signals; the scanner generates magnetic resonance signals of specific nuclides at the same time, and the magnetic resonance signal receiving device acquires the magnetic resonance signals at the same time.
In an embodiment, when at least two of the magnetic resonance signal receiving apparatuses are used, the magnetic resonance signal receiving apparatuses may respectively image, and specifically, the following two methods may be adopted: the scanner respectively generates magnetic resonance signals of specific nuclides, and the magnetic resonance signal receiving devices respectively acquire the magnetic resonance signals; the scanner simultaneously generates magnetic resonance signals of specific nuclides, and the magnetic resonance signal receiving devices respectively acquire the magnetic resonance signals.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent application shall be subject to the appended claims.
Claims (10)
1. A magnetic resonance signal receiving apparatus, comprising:
a tunable band-pass filter (101) for receiving and filtering the magnetic resonance signal;
an analog-to-digital converter (102) connected to the tunable band-pass filter (101) for converting the filtered magnetic resonance signal into a digital signal;
the adjusting module (103) is used for receiving a first control signal and adjusting the first control signal;
the input end of the low-pass filter (104) is connected with the adjusting module (103) and is used for filtering the adjusted first control signal;
a first control module (105), connected to the tunable bandpass filter (101), the analog-to-digital converter (102) and the adjusting module (103), for sending a first control signal to the adjusting module (103), and/or sending a second control signal for controlling the tunable bandpass filter (101), and/or sending a third control signal for controlling the analog-to-digital converter (102).
2. The magnetic resonance signal receiving apparatus of claim 1,
the tunable band-pass filter (101) comprises a chip element and/or a filter device built with discrete devices.
3. The magnetic resonance signal receiving apparatus of claim 2,
the filter device comprises at least one inductor and at least one capacitance value adjustable component, the at least one inductor and the at least one capacitance value adjustable component are connected to form a filter circuit, and the capacitance value adjustable component is further connected with the first control module (105).
4. A magnetic resonance signal receiving apparatus according to claim 3, wherein the filter means comprises a first inductance (L1), a second inductance (L2), a first capacitance-adjustable component (101 a), a second capacitance-adjustable component (101 b);
wherein one end of the first inductor (L1) receives a magnetic resonance signal, and the other end is grounded; the first end of the first capacitance value adjustable component (101 a) receives a magnetic resonance signal, the second end of the first capacitance value adjustable component (101 a) is grounded, and the control end of the first capacitance value adjustable component (101 a) is connected with a first control module (105); one end of the second inductor (L2) receives a magnetic resonance signal, the other end of the second inductor is connected with a second capacitance value adjustable component (101 b) in series, the second capacitance value adjustable component (101 b) outputs the filtered magnetic resonance signal, and the control end of the second capacitance value adjustable component (101 b) is connected with the first control module (105).
5. A magnetic resonance signal receiving apparatus as claimed in claim 4, wherein said filter means further comprises a third inductance (L3) and a third capacitance-adjustable component (101 c);
one end of the third inductor (L3) is connected with the output end of the second capacitance value adjustable component (101 b), and the other end of the third inductor is grounded; the first end of the third capacitance value adjustable component (101 c) is connected with the output end of the second capacitance value adjustable component (101 b), the second end of the third capacitance value adjustable component is grounded, and the control end of the third capacitance value adjustable component (101 c) is connected with the first control module (105).
6. The magnetic resonance signal receiving apparatus of claim 1,
the adjustable band-pass filter (101) is any one of an active band-pass filter, a Chebyshev filter, a Butterworth filter, an elliptic filter and a Bessel filter.
7. The magnetic resonance signal receiving apparatus of any one of claims 3 to 5,
the capacity value adjustable component comprises: at least two first capacitors connected in series and/or at least two second capacitors connected in parallel, wherein the first capacitors are respectively connected in parallel with a first switch, the second capacitors are respectively connected in series with a second switch, and the control ends of the first switches and the second switches are respectively connected with the first control module (105);
the first capacitor comprises a capacitor with a fixed capacitance value or an adjustable capacitance value, and the second capacitor comprises a capacitor with a fixed capacitance value or an adjustable capacitance value.
8. The magnetic resonance signal receiving apparatus as set forth in claim 1, further comprising:
the input end of the radio frequency power amplifier (106) receives a magnetic resonance signal, the output end of the radio frequency power amplifier (106) is connected with the adjustable band-pass filter (101), and the control end of the radio frequency power amplifier (106) is connected with the first control module (105) and is used for receiving and amplifying the magnetic resonance signal;
the first control module (105) sends a fourth control signal to a radio frequency power amplifier (106) for controlling the radio frequency power amplifier (106).
9. A magnetic resonance imaging apparatus, characterized by comprising at least one magnetic resonance signal receiving device (10) as claimed in any one of claims 1-8, further comprising:
a scanner (20) for generating magnetic resonance signals;
a receiving coil (30) connected with the scanner (20) to receive the magnetic resonance signal, the receiving coil (30) being connected with a magnetic resonance signal receiving device (10);
a data processing module (40) for receiving the digital signals and generating a magnetic resonance image.
10. The magnetic resonance imaging apparatus as set forth in claim 9, further comprising:
and the second control module (50) is connected with the magnetic resonance signal receiving device (10) and is used for controlling the first control module (105) to send the first control signal, the second control signal, the third control signal and the fourth control signal.
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| CN202221584491.5U CN217718070U (en) | 2022-06-23 | 2022-06-23 | Magnetic resonance signal receiving device and magnetic resonance imaging equipment |
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| CN202221584491.5U CN217718070U (en) | 2022-06-23 | 2022-06-23 | Magnetic resonance signal receiving device and magnetic resonance imaging equipment |
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