CN114062989A - Magnetic resonance spectrometer and magnetic resonance imaging system - Google Patents
Magnetic resonance spectrometer and magnetic resonance imaging system Download PDFInfo
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Abstract
The application discloses a magnetic resonance spectrometer and a magnetic resonance imaging system. The magnetic resonance spectrometer comprises: the micro control unit is respectively communicated with the gradient signal generating board, the radio frequency pulse signal generating board and the receiver, is used for controlling the operation of the gradient signal generating board, the radio frequency pulse signal generating board and the receiver through data sent by the upper computer, and sends the magnetic resonance signal acquired by the receiver to the upper computer; the radio frequency pulse signal generating board is used for sending pulse signals to the radio frequency general coil so as to excite the radio frequency general coil to generate a radio frequency magnetic field, so that a measured object generates a magnetic resonance phenomenon, and is provided with at least two radio frequency emission sources and a detection module for detecting a radio frequency energy deposition value; the receiver is used for receiving the magnetic resonance signals of the radio frequency receiving coil. Through the method and the device, the problems that a high-field magnetic resonance imaging system in the related art is poor in imaging quality and has potential safety hazards are solved.
Description
Technical Field
The application relates to the technical field of magnetic resonance, in particular to a magnetic resonance spectrometer and a magnetic resonance imaging system.
Background
The strength of the magnetic resonance signal is in direct proportion to the strength of the magnetic field, so that the improvement of the strength of the main magnetic field is an effective method for improving the signal-to-noise ratio of the magnetic resonance imaging system in the technical field of magnetic resonance imaging at present and is also the most common method.
It should be noted that the high-field magnetic resonance imaging system of 3T and above is developed based on the above principle. Researches show that the high-field magnetic resonance of 3T and above has obvious advantages in signal-to-noise ratio, and the structural imaging with isotropic resolution of 0.1mm can be realized. However, although high-field MRI systems have significant advantages in principle, they still have a series of technical problems in practice.
On one hand, compared with the current mainstream 1.5T magnetic resonance, a high-field magnetic resonance imaging system often has the problem of insufficient uniformity of a main magnetic field and a radio frequency field, and has serious radio frequency artifact and magnetic susceptibility effect during large imaging range scanning, thereby seriously affecting the image quality. On the other hand, high-field magnetic resonance still has more serious potential safety hazard, especially the risk such as the radio frequency energy deposition (SAR) value exceeds standard, therefore has more harsher safety condition restriction when using high-field equipment.
The spectrometer is the most critical and core device of the magnetic resonance imaging system and is responsible for sequence operation, radio frequency signal generation, spatial localization gradient signal generation, radio frequency signal reception, acquired data reconstruction and the like. The spectrometer architecture in the related art makes significant progress in digitization and distribution, and the reusability, stability and scanning speed of the spectrometer module also make significant progress. However, in order to rapidly introduce the high-field magnetic resonance of more than 3T to the market, the spectrometer of the high-field magnetic resonance of more than 3T is mainly upgraded from 1.5T, wherein the spectrometer technology only adjusts a few parameters such as a magnetic resonance imaging signal receiving frequency band, and the like, and meanwhile, for the difference of the high-field magnetic resonance of more than 3T relative to the other aspects of the low-field magnetic resonance, the demand of the high-field magnetic resonance of more than 3T on the spectrometer is generally met by a way of patching on the low-field magnetic resonance spectrometer. On one hand, the problem that the uniformity of a main magnetic field and a radio frequency field is not enough to influence the image quality is difficult to solve, and the problem that potential safety hazards exist due to risks such as exceeding of a radio frequency energy deposition value and the like is difficult to solve, so that a high-field-strength magnetic resonance system generated by a patching mode on a low-field magnetic resonance spectrometer is difficult to provide metabolic information; on the other hand, in a magnetic resonance system with low field strength, magnetic resonance signals of 1H protons are mostly used as imaging nuclear species, but from the perspective of physiological metabolism of the human body, physiological information carried by protons is very little, and almost no metabolic information can be provided.
Aiming at the problems that the imaging quality of a high-field magnetic resonance imaging system in the related technology is poor and potential safety hazards exist, an effective solution is not provided at present.
Disclosure of Invention
The application provides a magnetic resonance spectrometer and a magnetic resonance imaging system to solve the problems that a high-field magnetic resonance imaging system in the related art is poor in imaging quality and has potential safety hazards.
According to one aspect of the present application, a magnetic resonance spectrometer is provided. The method comprises the following steps: the micro control unit is respectively communicated with the gradient signal generating board, the radio frequency pulse signal generating board and the receiver, is used for controlling the operation of the gradient signal generating board, the radio frequency pulse signal generating board and the receiver through data sent by the upper computer, and sends the magnetic resonance signal acquired by the receiver to the upper computer; the gradient signal generating board is used for sending gradient waveform signals to the gradient coil so as to position a target scanning part of a measured object through the gradient waveform signals, wherein the gradient coil is arranged on the inner wall of the cylindrical magnet, and the measured object is arranged inside the cylindrical magnet; the radio frequency pulse signal generating board is used for sending pulse signals to the radio frequency general coil so as to excite the radio frequency general coil to generate a radio frequency magnetic field and enable a measured object to generate a magnetic resonance phenomenon, wherein the radio frequency general coil is arranged on the inner wall of the cylindrical magnet, at least two radio frequency emission sources are arranged on the radio frequency pulse signal generating board, and the at least two radio frequency emission sources are also connected with a detection module for detecting a radio frequency energy deposition value; the receiver is used for receiving magnetic resonance signals of the radio frequency receiving coil, wherein the radio frequency receiving coil is arranged inside the cylindrical magnet, and the distance between the radio frequency receiving coil and the target scanning part is smaller than a preset distance.
Optionally, the magnetic resonance spectrometer further comprises a spectrometer scanning control platform, wherein the spectrometer scanning control platform is connected with the micro control unit and used for sending data sent by the upper computer to the micro control unit and sending data received by the micro control unit to the upper computer.
Optionally, the values of the configuration parameters of each of the at least two radio frequency transmission sources are configured independently, wherein the configuration parameters include at least one of: amplitude, phase, and frequency.
Optionally, the detection module includes a detection circuit and a control circuit connected to each other, wherein the detection circuit is connected to the forward port of the rf power amplifier and the feedback port of the rf power amplifier in each rf emission source, and the forward port of the quadrature coupler and the feedback port of the quadrature coupler, and is configured to detect rf energy deposition at the target scanning location, wherein an input end of the quadrature coupler is connected to each rf power amplifier, an output end of the quadrature coupler is connected to the rf main coil, and the control circuit is configured to control the rf emission source to stop working when the rf energy deposition value at the target scanning location is greater than a preset value.
Optionally, the gradient signal generation board further receives a gradient waveform parameter and a zeroth order eddy current compensation parameter sent by the upper computer, calculates a carrier frequency compensation amount according to the gradient waveform parameter and the zeroth order eddy current compensation parameter, and sends the carrier frequency compensation amount to the radio frequency pulse signal generation board and the receiver, so as to superimpose the carrier frequency compensation amount on the carrier frequency of the radio frequency pulse signal generation board and the carrier frequency of the receiver, wherein the zeroth order eddy current compensation parameter includes a time parameter and an amplitude parameter corresponding to a zeroth order term of eddy current.
Optionally, the gradient signal generation board further receives a parameter of the first-order shimming sent by the upper computer, and superimposes the parameter of the first-order shimming on the gradient waveform signal, wherein the parameter of the first-order shimming is a bias voltage.
Optionally, the gradient signal generation board further receives parameters of the higher-order shimming sent by the upper computer, and transmits the parameters of the higher-order shimming to the shimming power supply, wherein the parameters of the higher-order shimming are bias currents.
Optionally, a plurality of first band-pass filters are respectively arranged at the output ends of the radio frequency emission sources, wherein the center frequency of each first band-pass filter is the frequency required by one type of nuclide imaging; and a plurality of second band-pass filters are correspondingly arranged at the input end of a receiving channel of the receiver respectively, wherein the center frequency of each second band-pass filter is the same as that of one first band-pass filter.
Optionally, a first modulation module is further disposed between the output end of each rf emission source and the plurality of first band-pass filters, and configured to perform amplitude modulation on the pulse signal output by the rf emission source, where the modulation module stores a plurality of first local oscillation frequencies, and each of the first local oscillation frequencies is a frequency required for one type of nuclide imaging; and a second modulation module is further arranged between the output ends of the plurality of first band-pass filters and the input end of the receiving channel of the receiver and used for carrying out amplitude demodulation on the received magnetic resonance signal, wherein the second modulation module stores a plurality of second local oscillation frequencies, and each second local oscillation frequency is the same as one first local oscillation frequency.
According to one aspect of the present application, a magnetic resonance imaging system is provided. The method comprises the following steps: a magnetic resonance spectrometer according to any one of the preceding claims; the imaging module is connected with the magnetic resonance spectrometer and used for receiving the data acquired by the magnetic resonance spectrometer and generating an image according to the acquired data; the upper computer is connected with the magnetic resonance spectrometer through the network switch and used for sending a control instruction to the magnetic resonance spectrometer and receiving data collected by the magnetic resonance spectrometer; and the imaging module is connected with the network switch and used for sending a control instruction to the imaging module and receiving the image generated by the imaging module.
Through this application, adopt: the micro control unit is respectively communicated with the gradient signal generating board, the radio frequency pulse signal generating board and the receiver, is used for controlling the operation of the gradient signal generating board, the radio frequency pulse signal generating board and the receiver through data sent by the upper computer, and sends the magnetic resonance signal acquired by the receiver to the upper computer; the gradient signal generating board is used for sending gradient waveform signals to the gradient coil so as to position a target scanning part of a measured object through the gradient waveform signals, wherein the gradient coil is arranged on the inner wall of the cylindrical magnet, and the measured object is arranged inside the cylindrical magnet; the radio frequency pulse signal generating board is used for sending pulse signals to the radio frequency general coil so as to excite the radio frequency general coil to generate a radio frequency magnetic field and enable a measured object to generate a magnetic resonance phenomenon, wherein the radio frequency general coil is arranged on the inner wall of the cylindrical magnet, at least two radio frequency emission sources are arranged on the radio frequency pulse signal generating board, and the at least two radio frequency emission sources are also connected with a detection module for detecting a radio frequency energy deposition value; the receiver is used for receiving magnetic resonance signals of the radio frequency receiving coil, wherein the radio frequency receiving coil is arranged inside the cylindrical magnet, and the distance between the radio frequency receiving coil and a target scanning part is smaller than a preset distance, so that the problems that a high-field magnetic resonance imaging system in the related art is poor in imaging quality and has potential safety hazards are solved. The radio-frequency pulse signal generation board is provided with at least two radio-frequency emission sources and a detection module for detecting a radio-frequency energy deposition value, multi-source emission and SAR value monitoring are realized by concentrating one unit, the product integration level is improved, the software control flow is simplified, and the SAR value detection module can report abnormal information to the control circuit in time, so that the control circuit can enable the radio-frequency emission function in time, and the effects of improving the imaging quality of a high-field magnetic resonance imaging system and reducing potential safety hazards are achieved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application. In the drawings:
figure 1 is a schematic diagram of a magnetic resonance spectrometer provided according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a detection module in a magnetic resonance spectrometer provided in accordance with an embodiment of the present application;
FIG. 3 is a schematic diagram of calculating a carrier frequency compensation amount according to a gradient waveform parameter and a zeroth order eddy current compensation parameter according to an embodiment of the present application;
FIG. 4 is a first order shimming schematic provided according to an embodiment of the present application;
FIG. 5 is a schematic diagram of an alternative RF pulse signal generating board provided in accordance with an embodiment of the present application;
FIG. 6 is a schematic diagram of an alternative receiver provided in accordance with an embodiment of the present application;
figure 7 is a schematic diagram of a magnetic resonance imaging system provided in accordance with an embodiment of the present application.
Detailed Description
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.
In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be used. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
According to an embodiment of the present application, a magnetic resonance spectrometer is provided.
Figure 1 is a schematic diagram of a magnetic resonance spectrometer according to an embodiment of the present application. As shown in fig. 1, the magnetic resonance spectrometer includes:
the micro control unit 10 is in communication with the gradient signal generating board 20, the radio frequency pulse signal generating board 30 and the receiver 40, and is configured to control operations of the gradient signal generating board 20, the radio frequency pulse signal generating board 30 and the receiver 40 through data sent by the upper computer, and send the magnetic resonance signal acquired by the receiver 40 to the upper computer.
The MCU 10 is a Main Control Unit (MCU) for short, and its hardware includes: the system comprises a plurality of high-speed optical fiber ports, a high-precision clock source generating module, a self-checking debugging module, a temperature monitoring module, an FPGA module, a board card information storage module, a power supply monitoring module and the like. The MCU can be connected with each hardware terminal of the magnetic resonance spectrometer based on a star-shaped topological structure and manages each hardware terminal, so that all the hardware terminals form a whole, and meanwhile, each hardware terminal exchanges information through the MCU to realize information synchronization.
Optionally, in the magnetic resonance spectrometer provided in the embodiment of the present application, the magnetic resonance spectrometer further includes a spectrometer scanning control platform 50, and the spectrometer scanning control platform 50 is connected to the micro control unit 10, and is configured to send data sent by the upper computer to the micro control unit 10, and send data received by the micro control unit 10 to the upper computer.
Specifically, the spectrometer scanning control platform 50 functions as an information exchange, receives a high-order instruction from the host computer, and compiles the instruction into data recognizable by the hardware MCU, and also receives data transmitted by the MCU and compiles the data into data recognizable by the host computer.
In addition, the magnetic resonance spectrometer comprises a monitoring unit 60 connected to the MCU for monitoring the operating conditions of the terminal modules connected to the MCU.
Wherein, the gradient signal generating board 20 is used for sending a gradient waveform signal to a gradient coil disposed on an inner wall of the cylindrical magnet to locate a target scanning portion of the object to be measured by the gradient waveform signal, wherein the object to be measured is disposed inside the cylindrical magnet.
Specifically, the hardware composition of the gradient signal generating board 20 itself includes: the system comprises a gradient output module, a gradient amplifier reference clock module, a gradient optical fiber communication module, a gate control module, an upper computer optical fiber communication module, a shimming power supply communication module, a self-checking debugging module, a temperature monitoring module, an FPGA module, a gradient board card information storage module, a power supply monitoring module and the like. The gradient signal generation board 20 analyzes the gradient event under the control of the spectrometer scanning control platform 50, thereby completing the generation of the three-axis high-precision gradient waveform.
The radio frequency pulse signal generating plate 30 is used for transmitting a pulse signal to the radio frequency general coil to excite the radio frequency general coil to generate a radio frequency magnetic field, so that the measured object generates a magnetic resonance phenomenon, wherein the radio frequency general coil is arranged on the inner wall of the cylindrical magnet, at least two radio frequency emission sources are arranged on the radio frequency pulse signal generating plate, and the at least two radio frequency emission sources are further connected with a detection module for detecting a radio frequency energy deposition value.
Specifically, the hardware components of the rf pulse signal generating board 30 themselves include: the system comprises a power supply module, an FPGA module, an SAR value real-time detection module, a board card information storage module, a power supply monitoring module, an LED (light Emitting diode) indicating unit and the like. In one aspect, at least two rf emission sources are disposed such that the rf pulse signal generating board 30 can generate rf pulse signals of a plurality of physical channels and output the rf pulse signals to the rf power amplifier, thereby significantly reducing non-uniformity of the rf field and reducing a large deposition of local SAR values. On the other hand, due to the arrangement of the detection module, the radio frequency pulse signal generation board 30 realizes the detection of a local radio frequency energy deposition Rate (SAR), and potential safety hazards caused by the radio frequency energy deposition in the working process of the magnetic resonance spectrometer are avoided. And moreover, multi-source emission and SAR value monitoring are realized by being integrated in one unit, the product integration level is improved, the software control flow is simplified, and the SAR value detection module can conveniently report abnormal information to the control circuit in time, so that the control circuit can enable the radio frequency emission function in time, and the effects of improving the imaging quality of the high-field magnetic resonance imaging system and reducing potential safety hazards are achieved.
Optionally, in the magnetic resonance spectrometer provided in the embodiment of the present application, the values of the configuration parameters of each of the at least two radio frequency emission sources are configured independently, where the configuration parameters include at least one of: amplitude, phase, and frequency.
Specifically, the radio frequency pulse envelope waveform, amplitude value, frequency and phase of each radio frequency emission source can be independently controlled and can be adjusted along with different scanning objects, so that on one hand, the nonuniformity of an MRI radio frequency field can be remarkably reduced, an imaging image can achieve better uniformity and contrast, and higher imaging spatial resolution is realized; on the other hand, the deposition distribution of the radio frequency energy in the imaging area is more uniform, the local SAR value is reduced, and the safety of the patient is improved.
For example, for magnetic resonance with 3T field strength, two completely independent rf emission sources can be designed on the rf pulse emission board. For another example, for magnetic resonance with field strength above 7T, the number of radio frequency transmission channels can be increased to 8 channels, thereby further improving the uniformity of the radio frequency field on the basis of 3T magnetic resonance and simultaneously reducing the local SAR value.
The receiver 40 is configured to receive a magnetic resonance signal of a radio frequency receiving coil, where the radio frequency receiving coil is disposed inside the cylindrical magnet, and a distance between the radio frequency receiving coil and the target scanning portion is smaller than a preset distance.
Specifically, the receiver 40 hardware components include: the system comprises at least one high-speed optical fiber port, an analog-to-Digital Converter (ADC), a programmable Digital control gain unit, a sound surface band-pass filter, a clock generation module with low phase noise, a self-checking debugging module, a temperature monitoring module, an FPGA module, a board card information storage module, a power supply monitoring module and the like.
In order to facilitate the layout and expansion of the receiver 40, it should be noted that the receiver 40 may include a plurality of receivers, each receiver 40 is provided with a plurality of signal receiving channels, and simultaneously receives the weak magnetic resonance signal from the radio frequency receiving coil, and performs low noise amplification, sampling quantization, quadrature demodulation, decimation filtering, and the like on the signal. Alternatively, each receiver 40 is designed to have 16 receive channels, and 8 receivers 40 are simultaneously placed on the side of the magnet, thereby extending to 128 receive channels.
The magnetic resonance spectrometer provided by the embodiment of the application is respectively communicated with the gradient signal generating board 20, the radio frequency pulse signal generating board 30 and the receiver 40 through the micro control unit 10, and is used for controlling the operation of the gradient signal generating board 20, the radio frequency pulse signal generating board 30 and the receiver 40 through data sent by an upper computer and sending the magnetic resonance signal acquired by the receiver 40 to the upper computer; wherein, the gradient signal generating board 20 is used for sending a gradient waveform signal to a gradient coil to locate a target scanning portion of a measured object by the gradient waveform signal, wherein the gradient coil is arranged on the inner wall of the cylindrical magnet, and the measured object is arranged inside the cylindrical magnet; the radio frequency pulse signal generating board 30 is used for sending a pulse signal to the radio frequency general coil to excite the radio frequency general coil to generate a radio frequency magnetic field, so that the measured object generates a magnetic resonance phenomenon, wherein the radio frequency general coil is arranged on the inner wall of the cylindrical magnet, at least two radio frequency emission sources are arranged on the radio frequency pulse signal generating board, and the at least two radio frequency emission sources are also connected with a detection module for detecting a radio frequency energy deposition value; the receiver 40 is configured to receive a magnetic resonance signal of a radio frequency receiving coil, where the radio frequency receiving coil is disposed inside the cylindrical magnet, and a distance between the radio frequency receiving coil and a target scanning portion is smaller than a preset distance, so as to solve problems of poor imaging quality and potential safety hazard of a high-field magnetic resonance imaging system in the related art. The radio-frequency pulse signal generation board is provided with at least two radio-frequency emission sources and a detection module for detecting a radio-frequency energy deposition value, multi-source emission and SAR value monitoring are realized by concentrating one unit, the product integration level is improved, the software control flow is simplified, and the SAR value detection module can report abnormal information to the control circuit in time, so that the control circuit can enable the radio-frequency emission function in time, and the effects of improving the imaging quality of a high-field magnetic resonance imaging system and reducing potential safety hazards are achieved.
Optionally, in the magnetic resonance spectrometer provided in the embodiment of the present application, the detection module includes a detection circuit and a control circuit connected to each other, where the detection circuit is connected to the forward port of the rf power amplifier and the feedback port of the rf power amplifier in each rf emission source, and the forward port of the quadrature coupler and the feedback port of the quadrature coupler, and is configured to detect rf energy deposition at a scanning portion of the object to be measured, where an input end of the quadrature coupler is connected to each rf power amplifier, an output end of the quadrature coupler is connected to the rf main coil, and the control circuit is configured to control the rf emission source to stop operating when a value of the rf energy deposition at the target scanning portion is greater than a preset value.
As shown in fig. 2, for the rf signal generating board provided with 2 rf emission sources, the detection circuit in the detection module detects the SAR values of the forward port and the feedback port of the dual-channel rf power amplifier, and the forward port and the feedback port of the quadrature coupler in real time, thereby realizing the detection of the SAR value of each monitoring point on the rf transmission link. The detection module also comprises an SAR value calculation unit which calculates the radio frequency deposition energy effectively loaded to the target scanning part according to the SAR value of each monitoring point. If the radio frequency deposition energy exceeds the standard, the radio frequency emission source is disabled through a scanning object safety protection mechanism of the control circuit, a radio frequency pulse signal output to the radio frequency power amplifier by the radio frequency emission source is cut off, real-time hardware interruption is achieved, specifically, the real-time response speed can reach the us level, further increase of the radio frequency deposition energy is effectively avoided, and therefore potential safety hazards are reduced.
In order to improve the detection accuracy of the nuclear magnetic resonance signal, optionally, in the magnetic resonance spectrometer provided in the embodiment of the present application, the gradient signal generation board 20 further receives a gradient waveform parameter and a zeroth order eddy current compensation parameter sent by the upper computer, calculates a carrier frequency compensation amount according to the gradient waveform parameter and the zeroth order eddy current compensation parameter, and sends the carrier frequency compensation amount to the radio frequency pulse signal generation board 30 and the receiver 40, so as to superimpose the carrier frequency compensation amount on the carrier frequency of the radio frequency pulse signal generation board 30 and the carrier frequency of the receiver 40, where the zeroth order eddy current compensation parameter includes a time parameter and an amplitude parameter corresponding to a zeroth order term of eddy current.
It should be noted that the gradient waveform generated by the gradient signal generating board 20 causes a frequency shift of the B0 field generated by the large magnet, while the frequency of the B0 field is the frequency of the carrier signal of the rf pulse signal generating board 30 and the receiver 40, and the frequency shift of the B0 field changes the frequency of the carrier signal, thereby affecting the detection accuracy of the nmr signal, and therefore, the carrier frequency needs to be compensated.
It should be noted that the gradient waveform parameters include three-axis (X, Y, Z) gradient waveform parameters, specifically include parameters for determining the shape of the gradient waveform, such as the slope of the rising edge and the falling edge, the duty ratio, the frequency, and the effective value, and the zero-order eddy current compensation parameters include three-axis (X, Y, Z) zero-order eddy current compensation parameters, and specifically include a time parameter and an amplitude parameter corresponding to the zero-order term of the eddy current.
Specifically, as shown in fig. 3, an X-axis B0 dominant frequency compensation amount B0_ pre-emp X is calculated through an X-axis gradient waveform parameter and an X-axis zeroth order eddy current compensation parameter; calculating to obtain Y-axis B0 dominant frequency compensation B0_ pre-emp Y through Y-axis gradient waveform parameters and Y-axis zero-order eddy current compensation parameters; and calculating to obtain Z-axis B0 main frequency compensation B0_ pre-emp Z through Z-axis gradient waveform parameters and Z-axis zero-order eddy current compensation parameters. Then, B0_ pre-emp X, B0_ pre-emp Y and B0_ pre-emp Z are accumulated together to obtain B0_ pre-emp, wherein B0_ pre-emp is the carrier frequency compensation quantity. Further, the carrier frequency compensation amount is simultaneously sent to the radio frequency pulse signal generating board 30 and the receiver 40, and is respectively superposed on the digital local oscillators of the radio frequency pulse signal generating board 30 and the receiver 40, thereby realizing the carrier frequency compensation. Specifically, the time accuracy of the control compensation amount may be once per 1us, and the frequency compensation amount accuracy may reach 1 Hz.
It should be noted that, in this embodiment, only one message channel needs to be reserved from the gradient signal generation board 20 to the radio frequency pulse signal generation board 30 and the receiver 40, and the carrier frequency compensation amount can be sent to the radio frequency pulse emission board 30 and the receiver 40 in real time, so that the structure of the magnetic resonance spectrometer is not changed while the carrier frequency compensation is realized, and the maintenance and the upgrade of the magnetic resonance spectrometer are facilitated.
In the high-field magnetic resonance system, the magnetic field uniformity at different positions inside the cavity of the cylindrical magnet may deviate to a certain extent, and in order to obtain a magnetic resonance image with uniform gray scale, the gradient field needs to be compensated.
Specifically, as shown in fig. 4, in the process of generating a gradient waveform digital signal by using gradient waveform parameters, during the radio frequency layer selection switching period during sequence operation, the calculated parameters (X _ shifting, Y _ shifting, Z _ shifting) of the first-order shimming corresponding to the radio frequency layer selection, that is, the bias voltages of the respective axes are transmitted to the X, Y, Z-axis gradient waveform digital channel of the gradient signal generating board 20, and are superimposed on the gradient waveform digital signal of the respective axes, and the gradient waveform digital signal on which the parameters of the first-order shimming are superimposed is output to the analog-to-digital converting unit and then is converted into a gradient analog waveform signal, so as to implement a first-order shimming layer, thereby improving the uniformity of the gradient magnetic field distribution.
In order to improve the uniformity of each magnetic field and thus improve the imaging quality, optionally, in the magnetic resonance spectrometer provided in the embodiment of the present application, the gradient signal generation board 20 further receives parameters of the higher-order shim transmitted by the upper computer, and transmits the parameters of the higher-order shim to the shim power supply, where the parameters of the higher-order shim are bias currents.
Specifically, during the switching period of the Repetition Time (TR for short) during the operation of the sequence, the parameters of the higher-order shimming are transmitted to the interface of the shimming power supply of the gradient signal generating board 20, and then the parameters of the higher-order shimming are transmitted to the shimming power supply according to the communication protocol specified by the shimming power supply, so that the shimming power supply is increased to supply power to the shimming coils, thereby increasing the uniformity of each magnetic field.
According to the embodiment, a first-order shim shimming technology and a high-order dynamic shimming technology are adopted to improve the shimming effect of a dynamic magnetic field, so that the imaging uniformity is improved, the geometric deformation of an image is reduced, particularly a diffusion image with a large susceptibility image is increased, the whole body diffusion imaging quality can be greatly improved under the condition that almost no extra time is added, the splicing artifacts among different scanning sections are reduced, and the imaging quality of a conventional diffusion challenging part is obviously improved.
In a magnetic resonance system with low field strength, a magnetic resonance signal of a 1H proton is generally used as an imaging nuclear species, but from the perspective of physiological metabolism of a human body, physiological information carried by the proton is very little, and almost no metabolic information can be provided. Some non-proton nuclides, such as 23Na sodium, 31P phosphorus and the like, represent the electrolyte equilibrium concentration inside and outside cells and tissues, carry abundant physiological and metabolic information of a human body, and can provide magnetic resonance signals at the same time, but the content of the non-proton nuclides in a living body is reduced by thousands of times compared with water molecules, so that the signal-to-noise ratio (SNR) of the obtained magnetic resonance image is very low, and the non-proton nuclides have no practical significance in a low-field strength magnetic resonance imaging system. Therefore, current spectrometers generally only consider the frequencies required for 1H imaging, not the frequencies required for 23Na, 31P imaging.
With the popularization and application of the ultrahigh field strength (7T, 9.4T) magnetic resonance imaging system, as the signal-to-noise ratio of a magnetic resonance image is enhanced along with the enhancement of the magnetic field strength, imaging of non-proton heteronuclear species such as 23Na, 31P and the like becomes possible, optionally, in the magnetic resonance spectrometer provided by the embodiment of the application, a plurality of first band pass filters are respectively arranged at the output end of each radio frequency emission source, wherein the center frequency of each first band pass filter is the frequency required by imaging of one type of nuclear species; a plurality of second bandpass filters are respectively disposed at the input end of the receiving channel of the receiver 40, wherein the center frequency of each second bandpass filter is the same as the center frequency of one first filter.
Optionally, in the magnetic resonance spectrometer provided in this embodiment of the present application, a first modulation module is further disposed between the output end of each radio frequency emission source and the plurality of first band pass filters, and is configured to perform amplitude modulation on the pulse signal output by the radio frequency emission source, where the modulation module stores a plurality of first local oscillation frequencies, and each first local oscillation frequency is a frequency required for one type of nuclide imaging; a second modulation module is further disposed between the output ends of the plurality of first band pass filters and the input end of the receiving channel of the receiver 40, and configured to perform amplitude demodulation on the received magnetic resonance signal, where the second modulation module stores a plurality of second local oscillation frequencies, and each second local oscillation frequency is the same as one first local oscillation frequency.
Specifically, a plurality of groups of band pass filters and local oscillation frequencies are respectively arranged on the radio frequency pulse signal generating board 30 and the receiver 40, when 1H, 23Na and 31P are imaged, one radio frequency switch for selecting three is used for switching, the switching speed can be completed within 1us, and the band pass filters and the local oscillation frequencies of the radio frequency pulse signal generating board 30 and the receiver 40 can be rapidly switched to the central frequencies required by 1H, 23Na and 31P imaging.
In an alternative embodiment, as shown in fig. 5, taking 3T magnetic resonance imaging as an example, in the digital logic of each physical transmission channel of the rf pulse signal generation board 30, the amplitude modulation of each nuclear species signal shares one quadrature modulation module, but each nuclear species signal has an independent local oscillation control word, and for a 1H signal, a local oscillation register 1 is used, and the value of the local oscillation register is set to 127.5 MHz; for the 23Na signal, local oscillation register 2 is used, and its value is set to 33.83 MHz; for the 31P signal, local oscillation register 3 is used, the value of which is set to 51.73 MHz.
Meanwhile, in the analog circuit of each physical transmission channel of the radio frequency pulse signal generating board 30, aiming at the 1H signal, a group of band-pass filters 1 with the center frequency of 127.5MHz and the-3 dB bandwidth of 1MHz are arranged; aiming at the 23Na signal, a group of band-pass filters 2 with the center frequency of 33.83MHz and the-3 dB bandwidth of 1MHz are arranged; and aiming at the 31P signal, a group of band-pass filters 3 with the center frequency of 51.73MHz and the bandwidth of-3 dB of 1MHz are arranged, and the band-pass filters are switched by using one radio frequency switch and three radio frequency switches.
As shown in fig. 6, for 3T MRI as an example, a set of band pass filters is designed for each nuclear species imaging in the analog circuits of each physical receiving channel of the receiver 40. As shown in the following figure, a group of band-pass filters 1 with the center frequency of 127.5MHz and the bandwidth of-3 dB of 1MHz are set for 1H signals; aiming at the 23Na signal, a group of band-pass filters 2 with the center frequency of 33.83MHz and the-3 dB bandwidth of 1MHz are arranged; for the 31P signal, a set of bandpass filters 3 with center frequency of 51.73MHz and bandwidth of-3 dB of 1MHz is set. The band-pass filter switching uses a one-to-three radio frequency switch for switching.
Meanwhile, in the digital logic of each physical receiving channel of the receiver 40, the amplitude demodulation of each nuclide signal shares one orthogonal demodulation module, but each nuclide signal has an independent local oscillation control word, and for a 1H signal, a local oscillation register 1 is used, and the value of the local oscillation register is set to 127.5 MHz; for the 23Na signal, local oscillation register 2 is used, and its value is set to 33.83 MHz; for the 31P signal, local oscillation register 3 is used, the value of which is set to 51.73 MHz.
Through the embodiment, a plurality of groups of band-pass filters and local oscillation frequencies are respectively arranged on the radio frequency pulse signal generating board 30 and the receiver 40, and the central frequencies required by different nuclide imaging can be obtained in a switching mode, so that multi-core imaging is realized, and magnetic resonance imaging can obtain richer human physiological and metabolic information compared with single 1H imaging.
According to another embodiment of the present application, a magnetic resonance imaging system is provided.
Figure 7 is a schematic diagram of a magnetic resonance imaging system according to an embodiment of the present application. As shown in fig. 7, the magnetic resonance imaging system includes:
the magnetic resonance spectrometer 11 according to any one of the above.
And the imaging module 13 is connected with the magnetic resonance spectrometer 11 and is used for receiving the data acquired by the magnetic resonance spectrometer 11 and generating an image according to the acquired data.
The upper computer 12 is connected with the magnetic resonance spectrometer 11 through a network switch, and is used for sending a control instruction to the magnetic resonance spectrometer 11 and receiving data acquired by the magnetic resonance spectrometer 11; and is also connected to the imaging module 13 through a network switch, and is configured to send a control instruction to the imaging module 13 and receive an image generated by the imaging module 13.
Specifically, host computer 12 can be for the scanning workstation, and host computer 12 sends the start instruction to magnetic resonance spectrometer 11 to the required parameter of work is sent to magnetic resonance spectrometer 11, specifically, earlier instruction or data transmission to magnetic resonance spectrometer 11's MCU, and each terminal module of connection is controlled to the MCU of rethread magnetic resonance spectrometer 11.
It should be noted that the object to be measured is located in the cylindrical magnet, the inner wall of the cylindrical magnet is provided with the gradient coil and the radio frequency general coil, the inside of the cylindrical magnet is also provided with the radio frequency receiving coil, and the radio frequency receiving coil is located near the target scanning position of the object to be measured. After the magnetic resonance spectrometer 11 is started, the spectrometer scanning control platform controls the gradient signal generation plate to send a gradient waveform signal to the gradient coil, and the target scanning part of the object to be measured is positioned. Furthermore, the spectrometer scanning control platform controls the radio frequency signal generating board to generate a radio frequency signal, and sends a pulse signal to the radio frequency general coil to excite the radio frequency general coil to generate a radio frequency magnetic field, so that a target scanning part of the object to be detected generates a magnetic resonance phenomenon. Meanwhile, the receiver receives the magnetic resonance signal of the radio frequency receiving coil inside the cylindrical magnet.
The receiver is after receiving the magnetic resonance signal, with magnetic resonance signal transmission to magnetic resonance spectrometer 11's MCU, MCU sends the magnetic resonance signal for imaging module 13, imaging module 13 passes through the magnetic resonance signal and generates the image to send the image that will generate to host computer 12, operating personnel can look over the image on host computer 12, can also be according to the further MCU to magnetic resonance spectrometer 11 of the condition of image data transmission, thereby the adjustment imaging result.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.
The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.
Claims (10)
1. A magnetic resonance spectrometer, comprising:
the micro control unit is respectively communicated with the gradient signal generating board, the radio frequency pulse signal generating board and the receiver, and is used for controlling the operation of the gradient signal generating board, the radio frequency pulse signal generating board and the receiver through data sent by an upper computer and sending the magnetic resonance signal acquired by the receiver to the upper computer;
the gradient signal generating board is used for sending gradient waveform signals to a gradient coil so as to position a target scanning part of a measured object through the gradient waveform signals, wherein the gradient coil is arranged on the inner wall of a cylindrical magnet, and the measured object is arranged inside the cylindrical magnet;
the radio frequency pulse signal generating plate is used for sending pulse signals to the radio frequency general coil so as to excite the radio frequency general coil to generate a radio frequency magnetic field, so that the measured object generates a magnetic resonance phenomenon, wherein the radio frequency general coil is arranged on the inner wall of the cylindrical magnet, at least two radio frequency emission sources are arranged on the radio frequency pulse signal generating plate, and the at least two radio frequency emission sources are also connected with a detection module for detecting a radio frequency energy deposition value;
the receiver is used for receiving a magnetic resonance signal of a radio frequency receiving coil, wherein the radio frequency receiving coil is arranged inside the cylindrical magnet, and the distance between the radio frequency receiving coil and the target scanning part is smaller than a preset distance.
2. The magnetic resonance spectrometer according to claim 1, further comprising a spectrometer scanning control platform connected to the micro control unit for sending data sent by the upper computer to the micro control unit and sending data received by the micro control unit to the upper computer.
3. The magnetic resonance spectrometer according to claim 1, wherein the values of the configuration parameters of each of the at least two radio frequency emission sources are configured independently, wherein the configuration parameters include at least one of: amplitude, phase, and frequency.
4. The magnetic resonance spectrometer according to claim 1, wherein the detection module comprises detection circuitry and control circuitry connected to a forward port of a radio frequency power amplifier and a feedback port of the radio frequency power amplifier in each of the radio frequency emission sources, and a forward port of a quadrature coupler and a feedback port of the quadrature coupler for detecting the deposition of radio frequency energy at the target scanning site, wherein an input of the quadrature coupler is connected to each of the radio frequency power amplifiers and an output of the quadrature coupler is connected to the radio frequency field coil, the control circuitry being configured to control the radio frequency emission sources to cease operation if the deposition of radio frequency energy at the target scanning site is greater than a predetermined value.
5. The magnetic resonance spectrometer according to claim 1, wherein the gradient signal generation board further receives a gradient waveform parameter and a zeroth order eddy current compensation parameter sent by the upper computer, calculates a carrier frequency compensation amount according to the gradient waveform parameter and the zeroth order eddy current compensation parameter, and sends the carrier frequency compensation amount to the radio frequency pulse signal generation board and the receiver so as to superimpose the carrier frequency compensation amount on a carrier frequency of the radio frequency pulse signal generation board and a carrier frequency of the receiver, wherein the zeroth order eddy current compensation parameter includes a time parameter and an amplitude parameter corresponding to a zeroth order term of eddy current.
6. The magnetic resonance spectrometer according to claim 1, wherein the gradient signal generation board further receives parameters of a first-order shim transmitted by the upper computer, and superimposes the parameters of the first-order shim into the gradient waveform signal, wherein the parameters of the first-order shim are bias voltages.
7. The magnetic resonance spectrometer of claim 1, wherein the gradient signal generation board further receives parameters of higher-order shimming sent by the upper computer and transmits the parameters of the higher-order shimming to a shim power supply, wherein the parameters of the higher-order shimming are bias currents.
8. A magnetic resonance spectrometer according to claim 1,
a plurality of first band-pass filters are respectively arranged at the output end of each radio frequency emission source, wherein the center frequency of each first band-pass filter is the frequency required by one type of nuclide imaging;
and a plurality of second band-pass filters are correspondingly arranged at the input end of a receiving channel of the receiver respectively, wherein the central frequency of each second band-pass filter is the same as the central frequency of one first band-pass filter.
9. A magnetic resonance spectrometer according to claim 8,
a first modulation module is further arranged between the output end of each radio frequency emission source and the plurality of first band-pass filters and is used for carrying out amplitude modulation on the pulse signals output by the radio frequency emission sources, wherein the modulation module stores a plurality of first local oscillation frequencies, and each first local oscillation frequency is a frequency required by one type of nuclide imaging;
and a second modulation module is further arranged between the output ends of the plurality of first band-pass filters and the input end of the receiving channel of the receiver and is used for performing amplitude demodulation on the received magnetic resonance signal, wherein the second modulation module stores a plurality of second local oscillation frequencies, and each second local oscillation frequency is the same as one first local oscillation frequency.
10. A magnetic resonance imaging system, comprising:
a magnetic resonance spectrometer as claimed in any one of claims 1 to 9;
the imaging module is connected with the magnetic resonance spectrometer and used for receiving the data acquired by the magnetic resonance spectrometer and generating an image according to the acquired data;
the upper computer is connected with the magnetic resonance spectrometer through a network switch and used for sending a control instruction to the magnetic resonance spectrometer and receiving data collected by the magnetic resonance spectrometer; the network switch is connected with the imaging module and used for sending a control instruction to the imaging module and receiving the image generated by the imaging module.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080265889A1 (en) * | 2005-10-07 | 2008-10-30 | Koninklijke Philips Electronics N. V. | Multiple-Channel Transmit Magnetic Resonance |
| US20080272783A1 (en) * | 2007-05-01 | 2008-11-06 | Kabushiki Kaisha Toshiba | Magnetic resonance imaging apparatus and magnetic resonance imaging method |
| US20120161766A1 (en) * | 2009-09-17 | 2012-06-28 | Koninklijke Philips Electronics N.V. | Concurrent optimization of rf power and rf field uniformity in mri |
| CN204207748U (en) * | 2014-09-26 | 2015-03-18 | 中国科学院生物物理研究所 | A kind of SAR real-time monitoring system of multi-channel magnetic resonance imaging equipment |
| US20150268321A1 (en) * | 2012-10-23 | 2015-09-24 | Koninklijke Philips N.V. | Adaptive specific absorption rate (sar) control for magnetic resonance imaging |
| US20180156879A1 (en) * | 2015-04-24 | 2018-06-07 | Koninklijke Philips N.V. | A multi-channel transmit/receive radio frequency (rf) system |
| US20180372814A1 (en) * | 2017-06-21 | 2018-12-27 | Toshiba Medical Systems Corporation | Magnetic resonance imaging apparatus and specific absorption rate calculation method |
| CN113296037A (en) * | 2021-05-21 | 2021-08-24 | 电子科技大学 | High-field magnetic resonance gradient controller |
-
2021
- 2021-11-11 CN CN202111335286.5A patent/CN114062989B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080265889A1 (en) * | 2005-10-07 | 2008-10-30 | Koninklijke Philips Electronics N. V. | Multiple-Channel Transmit Magnetic Resonance |
| US20080272783A1 (en) * | 2007-05-01 | 2008-11-06 | Kabushiki Kaisha Toshiba | Magnetic resonance imaging apparatus and magnetic resonance imaging method |
| US20120161766A1 (en) * | 2009-09-17 | 2012-06-28 | Koninklijke Philips Electronics N.V. | Concurrent optimization of rf power and rf field uniformity in mri |
| US20150268321A1 (en) * | 2012-10-23 | 2015-09-24 | Koninklijke Philips N.V. | Adaptive specific absorption rate (sar) control for magnetic resonance imaging |
| CN204207748U (en) * | 2014-09-26 | 2015-03-18 | 中国科学院生物物理研究所 | A kind of SAR real-time monitoring system of multi-channel magnetic resonance imaging equipment |
| US20180156879A1 (en) * | 2015-04-24 | 2018-06-07 | Koninklijke Philips N.V. | A multi-channel transmit/receive radio frequency (rf) system |
| US20180372814A1 (en) * | 2017-06-21 | 2018-12-27 | Toshiba Medical Systems Corporation | Magnetic resonance imaging apparatus and specific absorption rate calculation method |
| CN113296037A (en) * | 2021-05-21 | 2021-08-24 | 电子科技大学 | High-field magnetic resonance gradient controller |
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