Nuclear magnetic signal processing method, device, equipment and medium

Abstract

The invention discloses a nuclear magnetic signal processing method and device, equipment and a medium. According to the method, firstly, a free induction decay FID signal is obtained by collecting a nuclear magnetic signal, then a CPMG pulse sequence of pulses is applied on a time sequence in the transverse relaxation process of nuclear magnetic resonance of the FID signal, so that the phase and the dynamic process of the FID signal in different intervals from the 2nT moment to the (2n + 1) T moment of the time sequence are consistent, and finally, according to the processing requirement, the FID signal is obtained. And carrying out superposition processing on the FID signal, wherein the processing requirements comprise the improvement of the signal-to-noise ratio of the FID signal and the improvement of the resolution of the FID signal. In the process, the CPMG pulse sequence can directly form the FID signal into a plurality of echo signals, the plurality of echo signals can be directly used for processing subsequently, and the operation of multiple times of sampling is not needed, so that the efficiency and the effect of processing the nuclear magnetic signal to improve the signal strength and the signal resolution are improved.

Description

Technical Field

[0001] The present application relates to the field of nuclear magnetic resonance technology, and in particular to a method, device, equipment and medium for processing nuclear magnetic resonance signals. Background Art

[0002] Nuclear Magnetic Resonance (NMR) technology is commonly used in medical and chemical testing, and can also be used in quantum computing and other fields. Atomic nuclei will produce different energy levels in a magnetic field, and the nuclei will absorb the radio frequency field that resonates with their frequency to cause energy level transitions. If the energy level state of the atomic nuclei is excited by the radio frequency field, the free induction decay (FID) signal generated by the atomic nuclei can be measured in the experiment, thereby obtaining information about the chemical structure or quantum state of the sample. In order to better reflect the quantum state of the nuclear spin and the chemical structure of the compound in which the nuclear spin is located, the resolution and signal-to-noise ratio of the FID frequency domain signal must be good enough to improve the accuracy of parameter acquisition.

[0003] In nuclear magnetic resonance technology, the resolution of frequency domain signals can usually be improved by improving the uniformity of the magnetic field, and the signal-to-noise ratio can be improved by sampling multiple times and superimposing the signals. However, currently, improving the uniformity of the magnetic field requires active field shimming, which consumes manpower and resources; and improving the signal-to-noise ratio requires multiple sampling, which is also time-consuming. Summary of the invention

[0004] The present application provides a method, apparatus, device and medium for processing nuclear magnetic resonance signals, by applying a Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence to make the phase and dynamic process of the FID signal in different intervals from 2nT to (2n+1)T in the time sequence consistent, where n is a plurality of consecutive positive integers from 1 to a target value, T is the time interval from 0 in the time sequence to the first pulse application time, and superposition processing is performed on the FID signal, thereby improving the efficiency and effect of processing the nuclear magnetic resonance signal to improve the signal resolution and signal-to-noise ratio.

[0005] In a first aspect, the present application provides a method for processing nuclear magnetic resonance signals, characterized in that the method comprises:

[0006] By collecting nuclear magnetic signals, free induction decay FID signals are obtained;

[0007] In the transverse relaxation process of nuclear magnetic resonance of the FID signal, a π pulse in the CPMG pulse sequence is applied at the (2n-1)T moment in the time sequence, so that the FID signal generates a spin echo at the (2n-1)T moment in the time sequence, and a π pulse in the CPMG pulse sequence is applied at the 2nT moment in the time sequence, so that the phase of the FID signal is restored to the initial moment, wherein the phase of the FID signal in different intervals from the 2nT moment to the (2n+1)T moment in the time sequence is consistent with the dynamic process, n is a positive integer, and n is a plurality of continuous positive integers from 1 to a target value, and T is the time interval from the 0 moment in the time sequence to the moment of first pulse application;

[0008] The FID signals in the interval from time 0 to time T in multiple time sequences and the FID signals in different intervals from time 2nT to time (2n+1)T in multiple time sequences are superimposed to improve the signal-to-noise ratio of the FID signals.

[0009] Optionally, before the FID signal undergoes a transverse relaxation process of nuclear magnetic resonance, the method further includes:

[0010] The FID signal is converted from a time domain signal to a frequency domain signal through fast Fourier transform.

[0011] Optionally, the time interval between each π pulse in the timing sequence is T.

[0012] In a second aspect, the present application provides a method for processing nuclear magnetic resonance signals, the method comprising:

[0013] By collecting nuclear magnetic signals, free induction decay FID signals are obtained;

[0014] In the transverse relaxation process of nuclear magnetic resonance of the FID signal, a π pulse in the CPMG pulse sequence is applied at the (2n-1)T moment in the time sequence, so that the FID signal generates a spin echo at the (2n-1)T moment in the time sequence, and a π pulse in the CPMG pulse sequence is applied at the 2nT moment in the time sequence, so that the phase of the FID signal is restored to the initial moment, wherein the phase and dynamic process of the FID signal in different intervals from the 2nT moment to the (2n+1)T moment in the time sequence are consistent, n is a positive integer, and n is a plurality of continuous positive integers from 1 to a target value, and T is the time interval from the 0 moment in the time sequence to the moment of first pulse application;

[0015] The FID signal in the time interval from time 0 to time T in the time sequence is discarded, and the FID signal outside the time interval from time 0 to time T in the time sequence is superimposed to improve the resolution of the FID signal.

[0016] Optionally, before the FID signal undergoes a transverse relaxation process of nuclear magnetic resonance, the method further includes:

[0017] The FID signal is converted from a time domain signal to a frequency domain signal through fast Fourier transform.

[0018] Optionally, the time interval between each π pulse in the timing sequence is T.

[0019] In a third aspect, the present application provides a device for processing nuclear magnetic resonance signals, the device comprising:

[0020] An acquisition unit, used for acquiring a free induction decay (FID) signal by collecting a nuclear magnetic resonance signal;

[0021] An applying unit is used for applying a π pulse in a CPMG pulse sequence at a (2n-1)T moment in a time sequence during a transverse relaxation process of nuclear magnetic resonance of an FID signal, so that the FID signal generates a spin echo at a (2n-1)T moment in the time sequence, and applying a π pulse in the CPMG pulse sequence at a 2nT moment in the time sequence, so that the phase of the FID signal is restored to an initial moment, wherein the phase of the FID signal in different intervals from a 2nT moment to a (2n+1)T moment in the time sequence is consistent with the dynamic process, n is a positive integer, and n is a plurality of consecutive positive integers from 1 to a target value, and T is a time interval from a 0 moment in the time sequence to a moment of first pulse application;

[0022] The processing unit is used to superimpose the FID signals in the interval from time 0 to time T in multiple time sequences and the FID signals in different intervals from time 2nT to time (2n+1)T to improve the signal-to-noise ratio of the FID signals.

[0023] Optionally, the device further comprises:

[0024] The conversion unit is used to convert the FID signal from a time domain signal to a frequency domain signal through fast Fourier transform.

[0025] Optionally, the time interval between each π pulse in the timing sequence is T.

[0026] In a fourth aspect, the present application provides a device for processing nuclear magnetic resonance signals, the device comprising:

[0027] An acquisition unit, used for acquiring a free induction decay (FID) signal by collecting a nuclear magnetic resonance signal;

[0028] An applying unit is used for applying a π pulse in a CPMG pulse sequence at a (2n-1)T moment in a time sequence during a transverse relaxation process of nuclear magnetic resonance of an FID signal, so that the FID signal generates a spin echo at a (2n-1)T moment in the time sequence, and applying a π pulse in the CPMG pulse sequence at a 2nT moment in the time sequence, so that the phase of the FID signal is restored to an initial moment, wherein the phase of the FID signal in different intervals from a 2nT moment to a (2n+1)T moment in the time sequence is consistent with the dynamic process, n is a positive integer, and n is a plurality of consecutive positive integers from 1 to a target value, and T is a time interval from a 0 moment in the time sequence to a moment of first pulse application;

[0029] The processing unit is used to discard the FID signal in the interval from time 0 to time T in the time sequence, and to superimpose the FID signal except the interval from time 0 to time T in the time sequence, so as to improve the resolution of the FID signal.

[0030] Optionally, the device further comprises:

[0031] The conversion unit is used to convert the FID signal from a time domain signal to a frequency domain signal through fast Fourier transform.

[0032] Optionally, the time interval between each π pulse in the timing sequence is T.

[0033] In a fifth aspect, the present application provides an electronic device, the electronic device comprising a memory and a processor:

[0034] The memory is used to store computer programs;

[0035] The processor is used to execute the method provided by the first aspect or the second aspect according to the computer program.

[0036] In a sixth aspect, the present application provides a computer-readable storage medium, which is used to store a computer program, and the computer program is used to execute the method provided in the first aspect or the second aspect above.

[0037] It can be seen that this application has the following beneficial effects:

[0038] The present application provides a method for processing nuclear magnetic resonance signals. First, a free induction decay (FID) signal is obtained by collecting nuclear magnetic resonance signals. Then, during the transverse relaxation process of nuclear magnetic resonance of the FID signal, a π pulse in a CPMG pulse sequence is applied at the (2n-1)T moment in a time sequence, so that the FID signal generates a spin echo at the (2n-1)T moment in the time sequence. The π pulse in the CPMG pulse sequence is applied at the 2nT moment in the time sequence, so that the phase of the FID signal is restored to the initial moment, wherein the phase of the FID signal in different intervals from the 2nT moment to the (2n+1)T moment in the time sequence is consistent with the dynamic process, n is a positive integer, and n takes multiple continuous positive integers from 1 to a target value, and T is the time interval from the 0 moment to the first pulse application moment in the time sequence; finally, the FID signals in the interval from the 0 moment to the T moment in multiple time sequences and the FID signals in different intervals from the 2nT moment to the (2n+1)T moment in the time sequence are superimposed to improve the signal-to-noise ratio of the FID signal. In this process, under the action of multiple π pulses of the CPMG pulse sequence, the phase and dynamic process of the FID signal in different intervals from 2nT to (2n+1)T in the time sequence can be made consistent, that is, multiple echo signals can be directly formed through the CPMG pulse sequence, so that multiple echo signals can be directly used for processing without multiple sampling operations, so as to improve the efficiency and effect of processing nuclear magnetic signal and improving signal-to-noise ratio.

[0039] The present application also provides a method for processing nuclear magnetic signals, firstly, acquiring a free induction decay (FID) signal by collecting nuclear magnetic signals, and then, in the transverse relaxation process of nuclear magnetic resonance of the FID signal, applying a π pulse in a CPMG pulse sequence at the (2n-1)T moment in the time sequence, so that the FID signal generates a spin echo at the (2n-1)T moment in the time sequence, and applying a π pulse in the CPMG pulse sequence at the 2nT moment in the time sequence, so that the phase of the FID signal is restored to the initial moment, wherein the phase and dynamic process of the FID signal in different intervals from the 2nT moment to the (2n+1)T moment in the time sequence are consistent, n is a positive integer, and n takes multiple consecutive positive integers from 1 to a target value, and T is the time interval from the 0th moment in the time sequence to the first pulse application moment; finally, the FID signal in the interval from the 0th moment to the Tth moment in the time sequence is discarded, and the FID signals except the interval from the 0th moment to the Tth moment in the time sequence are superimposed to improve the resolution of the FID signal. In this process, under the action of multiple π pulses of the CPMG pulse sequence, the phase and dynamic process of the FID signal in different intervals from 2nT to (2n+1)T in the time sequence can be made consistent, that is, multiple echo signals can be directly formed through the CPMG pulse sequence, so that multiple echo signals can be directly used for processing without multiple sampling operations, so as to improve the efficiency and effect of processing nuclear magnetic resonance signals and improving signal resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0041] Figure 1 This is a schematic diagram of the dynamic phase process of the spin echo in the embodiment of the present application;

[0042] Figure 2 A schematic diagram of a spectrum signal of a spin echo pulse in an embodiment of the present application;

[0043] Figure 3 A schematic diagram of a spectrum signal of a spin echo pulse with a constant phase in an embodiment of the present application;

[0044] Figure 4 This is a flow chart of an embodiment of a method for processing nuclear magnetic resonance signals in an embodiment of the present application;

[0045] Figure 5 A schematic diagram of converting a time domain signal into a frequency domain signal in an embodiment of the present application;

[0046] Figure 6 A schematic diagram of a spectrum signal of a spin echo pulse and a spectrum signal of a CPMG-4 pulse sequence in an embodiment of the present application;

[0047] Figure 7 A schematic diagram of a spectrum signal of a CPMG pulse sequence in an embodiment of the present application;

[0048] Figure 8 It is a schematic diagram of superimposed spectrum signals of FID signals with and without a CPMG pulse sequence in an embodiment of the present application;

[0049] Fig. 9 This is a flow chart of another embodiment of a method for processing nuclear magnetic resonance signals in an embodiment of the present application;

[0050] Fig.10 It is a schematic diagram of a superimposed spectrum curve of an FID signal with a CPMG pulse sequence and without a CPMG pulse sequence in an embodiment of the present application;

[0051] Fig.11 This is a schematic structural diagram of an embodiment of a device for processing nuclear magnetic resonance signals in an embodiment of the present application;

[0052] Fig.12 This is a structural schematic diagram of another embodiment of a device for processing nuclear magnetic resonance signals in the embodiments of the present application;

[0053] Fig.13 It is a schematic diagram of the structure of an electronic device in an embodiment of the present application. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards of relevant countries and regions.

[0056] First, the technical terms that may appear in the embodiments of the present application are explained here:

[0057] (1) Nuclear magnetic resonance: The process in which non-zero spin atomic nuclei absorb electromagnetic waves of a specific frequency and undergo energy level transitions under the action of an external magnetic field. Non-zero spin atomic nuclei have magnetic moments, and their spin energy levels undergo Zeeman splitting under the action of an external magnetic field.

[0058] (2) Spin echo: It is a signal source in the magnetic resonance phenomenon. Compared with the free induction decay (FID) that appears immediately after the first radio frequency pulse (RF pulse) excitation, the spin echo is a signal that grows back after the dephased magnetization vector is refocused after the second radio frequency pulse.

[0059] During the ongoing transverse relaxation process, if a 180-degree RF pulse is applied to the FID signal, the spins in the FID signal will be "reversed", and because the previous phase dispersion is offset, an "echo" signal is eventually formed. This is the basic principle of spin echo. We can use an independent ensemble of three spins as an example, where the net transverse magnetic moment is the average of the spin magnetic moments on three different molecules, and assuming that the total spin evolution time is t, the following is divided into 5 stages and combined with Figure 1 Let's discuss the dynamics of spin echo:

[0060] The first is the initial moment. Figure 1As shown in the first small picture in the figure, the spins on the three different spin molecules above are all facing the x direction, and the phases are all 0. At this time, the polarization is the highest and the transverse net magnetic moment of the ensemble is the largest.

[0061] The second is the time before t / 2. Figure 1 As shown in the second small figure, due to the inhomogeneity of the magnetic field, the three spin molecules have three different Larmor frequencies. In the first t / 2 time, the three spins accumulate phases at different speeds. At this time, the polarization decreases and the transverse net magnetic moment of the ensemble decreases.

[0062] The third one is at time t / 2. Figure 1 As shown in the third small figure in the figure, at this time the three spin molecules have accumulated different phases. At this time, a pulse is applied to all the spin molecules in the ensemble, and the three spin molecules rotate 180° around the x-axis at the same time, so their phases become negative.

[0063] The fourth is within the time after t / 2. Figure 1 As shown in the fourth small figure in the figure, the three spin molecules continue to precess around the z-axis at three different Larmor frequencies, and the three spins continue to accumulate phases at different speeds. In this process, the phase difference between the three spin molecules gradually decreases, the polarization degree is restored, and the transverse net magnetic moment of the ensemble gradually increases.

[0064] The fifth is at time t. Figure 1 As shown in the fifth small figure in the figure, the accumulated phase of the three spin molecules returns to 0, the polarization is restored to the maximum, and the transverse net magnetic moment of the ensemble is restored to a maximum value that can be recovered.

[0065] That is, from the above dynamic description, we can see that Figure 2 As shown in the figure, the oscillation decays in the first t / 2 time, and increases in the second t / 2 time, reaching a maximum value at time t and then oscillating and decaying again. In this frequency domain spectrum, the transverse magnetic moment of the spin ensemble reappears like an echo in a valley, so this phenomenon is called "spin echo".

[0066] In the actual process of quantum information processing, such as Figure 3 As shown in Figure 1, the pulse sequence of the spin echo usually applies another pulse during the echo to adjust the phase. In this way, no matter what the initial state of the quantum bit is, no matter what the phase of the applied pulse is, the phase of the spin echo can always be consistent with the phase of the initial state.

[0067] (3) Spin echo multiple echo (Carr-Purcell-Meiboom-Gill, CPMG) pulse sequence: It is a commonly used magnetic resonance imaging technique, mainly used to measure and analyze the spin-spin interaction and dynamic characteristics of the sample. The CPMG sequence generates a series of magnetic field pulses through the cyclotron process of multiple rotation and reversal of spins, which causes the spin vector to circle in the xy plane and generate radio frequency signals.

[0068] At present, in order to better reflect the quantum state of nuclear spins and the chemical structure of the compounds in which the nuclear spins are located, the resolution and signal-to-noise ratio of the FID frequency domain signal must be good enough to improve the accuracy of the acquired parameters. In nuclear magnetic resonance technology, the resolution of the frequency domain signal can be improved by improving the uniformity of the magnetic field; and the signal-to-noise ratio of the signal can be improved by sampling multiple times and superimposing the signal. However, in order to improve the uniformity of the magnetic field, active field shimming is required, such as fine adjustment of the magnet and compensation by using coils to generate magnetic fields, but this kind of thing will consume manpower, energy and resources; and improving the signal-to-noise ratio requires multiple sampling, which is also time-consuming.

[0069] In an embodiment of the present application, a CPMG pulse sequence is applied to the FID frequency domain signal to make the phase and dynamic process of the FID signal consistent in different intervals from 2nT to (2n+1)T in the timing sequence, and the FID signal is superimposed without the need to sample multiple echoes, that is, it does not require time and effort, and can also improve the signal-to-noise ratio and resolution of the FID frequency domain signal, thereby improving the efficiency and effect of processing nuclear magnetic resonance signals to improve the signal-to-noise ratio and signal resolution.

[0070] To facilitate understanding of the specific implementation of the method for processing nuclear magnetic resonance signals provided in the embodiment of the present application, it will be described below with reference to the accompanying drawings.

[0071] It should be noted that the subject implementing the method for processing nuclear magnetic signals may be a device for processing nuclear magnetic signals provided in the embodiment of the present application, and the device for processing nuclear magnetic signals may be carried in an electronic device or a functional module of an electronic device. The electronic device in the embodiment of the present application may be any device capable of implementing the method for processing nuclear magnetic signals in the embodiment of the present application, for example, an Internet of Things (IoT) device.

[0072] Figure 4 The present invention provides a flow chart of a method for processing nuclear magnetic signals in accordance with an embodiment of the present invention. The method can be applied to a device for processing nuclear magnetic signals, which can be, for example, Fig.11 The apparatus 1100 for processing nuclear magnetic signals shown in FIG. 1 may also be integrated in Fig.12Functional modules in the electronic device 1200 are shown.

[0073] like Figure 4 As shown, the method includes the following steps S401 to S403:

[0074] S401: Obtain free induction decay (FID) signals by collecting nuclear magnetic resonance signals.

[0075] In order to read the parameters in the nuclear magnetic signal, it is first necessary to acquire the free induction decay FID signal by collecting the nuclear magnetic signal, and then apply the π pulse in the CPMG pulse sequence at the (2n-1)T moment in the time sequence during the transverse relaxation process of the nuclear magnetic resonance of the FID signal, so that the FID signal generates a spin echo at the (2n-1)T moment in the time sequence, and apply the π pulse in the CPMG pulse sequence at the 2nT moment in the time sequence, so that the phase of the FID signal is restored to the initial moment; finally, the FID signals in the interval from 0 to T in multiple segments of the time sequence and the FID signals in different intervals from 2nT to (2n+1)T are superimposed to improve the signal-to-noise ratio of the FID signal. Therefore, the embodiment of the present application obtains the FID signal through S401, and makes a preliminary preparation for the subsequent application of the CPMG pulse sequence.

[0076] Since the above introduction explains that the nuclear magnetic signal that decays with time is the FID signal, in this embodiment of the present application, the FID signal is obtained by collecting the nuclear magnetic signal.

[0077] If there are multiple frequency components in the FID signal, the representation in the time domain will become very complicated. In order to analyze the FID signal more intuitively, it is usually Figure 5 As shown, the FID signal is converted from a time domain signal to a frequency domain signal through Fast Fourier Transform (FFT).

[0078] S402: During the transverse relaxation process of the FID signal undergoing nuclear magnetic resonance, a π pulse in the CPMG pulse sequence is applied at the (2n-1)T moment in the time sequence, so that the FID signal generates a spin echo at the (2n-1)T moment in the time sequence, and a π pulse in the CPMG pulse sequence is applied at the 2nT moment in the time sequence, so that the phase of the FID signal is restored to the initial moment, wherein the phase of the FID signal in different intervals from the 2nT moment to the (2n+1)T moment in the time sequence is consistent with the dynamic process, n is a positive integer, and n takes multiple consecutive positive integers from 1 to a target value, and T is the time interval from the 0 moment in the time sequence to the moment of first pulse application.

[0079] The CPMG pulse sequence used in the embodiment of the present application has a better effect on echoes with a long time span. Figure 6 As shown in the first figure in , for a spin echo pulse sequence, the longer the t / 2 time is, the more spin polarization disappears due to factors other than magnetic field inhomogeneity. Once the t / 2 time is too long, spin echo will not occur. Therefore, inserting multiple equally spaced pulses over a long span of time can reduce the decrease in spin polarization caused by other factors, thereby extending the time span of the spin echo to the maximum extent. Figure 6 As shown in the second figure in the figure, CPMG-n usually means that n π pulses are applied in time, and the time interval between each pulse is Here, t refers to the duration covered by the entire CPMG sequence, and n is a positive integer.

[0080] Assuming that the first pulse in the CPMG pulse sequence is applied at t = T, the FID signal will generate a spin echo at 2T. If another pulse is applied at t = 2T, the FID signal will recover to the phase at the initial time t = 0 while maintaining the maximum value of the echo signal.

[0081] As described in the principle of the dynamic description of spin echo, it is necessary to apply the pulse in the CPMG pulse sequence at a certain moment. In the embodiment of the present application, the moment (2n-1)T is selected, so that the FID signal can generate a spin echo at the moment (2n-1)T of the timing sequence. And it is necessary to apply another pulse to adjust the phase during the echo. Therefore, the present application also needs to apply the pulse in the CPMG pulse sequence at the moment 2nT in the timing sequence, that is, the time interval of each π pulse in the timing sequence of the FID signal is T, so that no matter how much the phase of the applied pulse is, the phase during the spin echo can always be consistent with the phase of the initial state, and at this time the FID signal reaches the maximum value of the spin echo, that is, the phase of the FID signal in different intervals from the moment 2nT to the moment (2n+1)T of the timing sequence is consistent with the dynamic process.

[0082] It should be noted that in the embodiment of the present application, n is a plurality of consecutive positive integers from 1 to the target value, wherein n is a plurality of consecutive positive integers, which means two or more consecutive positive integers, that is, n is a continuous numerical sequence of 1, 2, 3, rather than a continuous odd or even numerical sequence. For example, in the timing of the FID signal, within the time period t=2T to t=3T, within the time period t=4T to t=5T, and within the time period t=6T to t=7T, and so on, the phases and dynamic processes in the above multiple time periods are consistent, such as Figure 7As shown, under the action of multiple pulses of the CPMG pulse sequence, multiple echo signals are generated in different intervals from t = 2nT to t = (2n + 1)T, and the information (phase, dynamic process) carried by the FID signal in the multiple echo signals is consistent, that is, the phase and dynamic process in different intervals from t = 2nT to t = (2n + 1)T in the entire time sequence are consistent. And the time interval of each pulse in the time sequence is T.

[0083] In this process, the CPMG pulse sequence can be used to form multiple echo signals by applying π pulses multiple times, so that the phase and dynamic process in different intervals from 2nT to (2n+1)T in the time sequence are consistent, so that multiple echo signals can be directly used for processing without the need to perform multiple sampling operations on the echo signals, thereby improving the efficiency of subsequent processing to improve the signal-to-noise ratio of the FID signal.

[0084] S403: superimposing the FID signals in the interval from time 0 to time T in the multiple time sequences and the FID signals in different intervals from time 2nT to time (2n+1)T to improve the signal-to-noise ratio of the FID signals.

[0085] In the embodiment of the present application, due to the use of the CPMG pulse sequence, multiple echo signals can be directly used for processing, for example, to improve the signal-to-noise ratio of the FID signal. In this process, under the premise that the phase and dynamic process in different intervals from 2nT to (2n+1)T in the time sequence are consistent, the FID signals in the interval from 0 to T in multiple time sequences and the FID signals in different intervals from 2nT to (2n+1)T are superimposed, and the signal strength will be improved. And because the noise is random, it will not be enhanced with the superposition of multiple signal segments, so the signal-to-noise ratio of the superimposed FID signal is improved. Figure 8 As shown, Figure 8 The first figure shows the signal intensity obtained by applying the CPMG pulse sequence and superimposing the FID signal. Figure 8 The second picture shows that the signal intensity is enhanced only after the FID signal superposition processing.

[0086] It can be seen that the embodiment of the present application can make the phase and oscillation trend of the FID signal in different intervals from 2nT to (2n+1)T consistent by applying the CPMG pulse sequence, that is, multiple echo signals can be directly formed through the CPMG pulse sequence, and the multiple echo signals can be directly used for superposition processing later, without the need to sample multiple echoes, so as to improve the efficiency and effect of processing nuclear magnetic resonance signals to improve the signal-to-noise ratio.

[0087] The method for processing nuclear magnetic signals provided in the present application can not only improve the efficiency and effect of processing nuclear magnetic signals to improve the signal-to-noise ratio, but also improve the efficiency and effect of processing nuclear magnetic signals to improve the signal resolution. Fig. 9 A specific example of a method for processing nuclear magnetic resonance signals provided in the present application for improving the efficiency and effectiveness of processing nuclear magnetic resonance signals and improving signal resolution is described.

[0088] like Fig. 9 As shown, the method includes the following steps S901 to S903:

[0089] S901: Obtain free induction decay (FID) signal by collecting nuclear magnetic resonance signals.

[0090] In order to read the parameters in the nuclear magnetic signal, it is first necessary to acquire the free induction decay FID signal by collecting the nuclear magnetic signal, and then apply the π pulse in the CPMG pulse sequence at the (2n-1)T moment in the time sequence during the transverse relaxation of the nuclear magnetic resonance of the FID signal, so that the FID signal generates a spin echo at the (2n-1)T moment in the time sequence, and apply the π pulse in the CPMG pulse sequence at the 2nT moment in the time sequence, so that the phase of the FID signal is restored to the initial moment; finally, the FID signal in the interval from 0 to T in the time sequence is discarded, and the FID signal except the interval from 0 to T in the time sequence is superimposed to improve the resolution of the FID signal. Therefore, the embodiment of the present application obtains the FID signal through S901, and makes a preliminary preparation for the subsequent application of the CPMG pulse sequence.

[0091] Since the above introduction explains that the nuclear magnetic signal that decays with time is the FID signal, in this embodiment of the present application, the FID signal is obtained by collecting the nuclear magnetic signal.

[0092] If there are multiple frequency components in the FID signal, the representation in the time domain will become very complicated. In order to analyze the FID signal more intuitively, the FID signal can be converted from a time domain signal to a frequency domain signal by fast Fourier transform, for example, in the above embodiment.

[0093] S902: During the transverse relaxation process of the FID signal undergoing nuclear magnetic resonance, a π pulse in the CPMG pulse sequence is applied at the (2n-1)T moment in the time sequence, so that the FID signal generates a spin echo at the (2n-1)T moment in the time sequence, and a π pulse in the CPMG pulse sequence is applied at the 2nT moment in the time sequence, so that the phase of the FID signal is restored to the initial moment, wherein the phase and dynamic process of the FID signal in different intervals from the 2nT moment to the (2n+1)T moment in the time sequence are consistent, n is a positive integer, and n takes multiple consecutive positive integers from 1 to a target value, and T is the time interval from the 0 moment in the time sequence to the moment of first pulse application.

[0094] For example, as shown in the above embodiment, in the embodiment of the present application, the time (2n-1)T is selected, so that the FID signal can generate a spin echo at the time (2n-1)T of the timing sequence. And the pulse in the CPMG pulse sequence is applied at the time 2nT in the timing sequence, that is, the time interval of each π pulse in the timing sequence of the FID signal is T, so that no matter how much the phase of the applied pulse is, the phase during the spin echo can always be consistent with the phase of the initial state, and at this time the FID signal reaches the maximum value of the spin echo, that is, the phase of the FID signal in different intervals from the time 2nT to the time (2n+1)T of the timing sequence is consistent with the dynamic process.

[0095] It should be noted that in the embodiment of the present application, n takes multiple consecutive positive integers from 1 to the target value, where n is multiple consecutive positive integers, which means two or more consecutive positive integers, that is, n takes a continuous numerical sequence such as 1, 2, and 3, rather than an odd or even continuous numerical sequence. For example, in the timing of the FID signal, within the time period t=2T to t=3T, within the time period t=4T to t=5T, and within the time period t=6T to t=7T, and so on, the phases and dynamic processes in the above multiple time periods are consistent.

[0096] In this process, the CPMG pulse sequence can be used to form multiple echo signals by applying π pulses multiple times, so that the phase and dynamic process in different intervals from 2nT to (2n+1)T in the time sequence are consistent, so that multiple echo signals can be directly used for processing without the need to perform multiple sampling echo signal operations, thereby improving the efficiency of subsequent processing to improve the resolution of the FID signal.

[0097] S903: discard the FID signal in the time interval from time 0 to time T in the time sequence, and superimpose the FID signal except the time interval from time 0 to time T in the time sequence to improve the resolution of the FID signal.

[0098] In the embodiment of the present application, since the CPMG pulse sequence can be used to directly use multiple echo signals for processing, for example, to improve the resolution of the FID signal. In the process, the fastest decaying component in the FID signal can be filtered, that is, the FID signal in the interval from time 0 to time T in the time sequence is discarded, so that the remaining FID signals except the interval from time 0 to time T in the time sequence are superimposed, which can significantly improve the resolution of the FID signal. Fig.10 As shown, the lower and narrower FFT below is obtained by applying a CPMG pulse sequence and superimposing the FID signal, while the higher and wider FFT above is only obtained by superimposing the FID signal. It can be seen that the signal peak resolution of the lower and narrower FFT below is better, that is, the effect of the method for improving the resolution of the FID signal in the embodiment of the present application is also enhanced.

[0099] It can be seen that the embodiment of the present application can make the phase and oscillation trend of the FID signal in different intervals from 2nT to (2n+1)T consistent by applying the CPMG pulse sequence, that is, a plurality of echo signals can be directly formed through the CPMG pulse sequence, and the plurality of echo signals can be directly used to filter the fastest decaying component in the FID signal, that is, the FID signal in the interval from 0 to T in the time sequence is discarded, and the remaining FID signals except the interval from 0 to T in the time sequence are superimposed to improve the efficiency and effect of processing nuclear magnetic signal to improve signal resolution.

[0100] See also Fig.11 The present application embodiment provides a device 1100 for processing nuclear magnetic resonance signals, the device comprising:

[0101] An acquisition unit 1101 is used to acquire a free induction decay (FID) signal by collecting a nuclear magnetic resonance signal;

[0102] The applying unit 1102 is used to apply a π pulse in the CPMG pulse sequence at a time (2n-1)T in the time sequence during the transverse relaxation process of the FID signal for nuclear magnetic resonance, so that the FID signal generates a spin echo at a time (2n-1)T in the time sequence, and to apply a π pulse in the CPMG pulse sequence at a time 2nT in the time sequence, so that the phase of the FID signal is restored to an initial time, wherein the phase of the FID signal in different intervals from a time 2nT to a time (2n+1)T in the time sequence is consistent with the dynamic process, n is a positive integer, and n is a plurality of consecutive positive integers from 1 to a target value, and T is a time interval from a time 0 in the time sequence to a time when the pulse is first applied;

[0103] The processing unit 1103 is used to superimpose the FID signals in the interval from time 0 to time T in the multiple time sequences and the FID signals in different intervals from time 2nT to time (2n+1)T to improve the signal-to-noise ratio of the FID signals.

[0104] Optionally, the device 1100 further includes:

[0105] The conversion unit is used to convert the FID signal from a time domain signal to a frequency domain signal through fast Fourier transform.

[0106] Optionally, the time interval between each π pulse in the timing sequence is T.

[0107] See also Fig.12 The present application embodiment provides a device 1200 for processing nuclear magnetic resonance signals, the device comprising:

[0108] An acquisition unit 1201 is used to acquire a free induction decay (FID) signal by collecting a nuclear magnetic resonance signal;

[0109] The applying unit 1202 is used to apply a π pulse in the CPMG pulse sequence at a time (2n-1)T in the time sequence during the transverse relaxation process of the FID signal undergoing nuclear magnetic resonance, so that the FID signal generates a spin echo at a time (2n-1)T in the time sequence, and to apply a π pulse in the CPMG pulse sequence at a time 2nT in the time sequence, so that the phase of the FID signal is restored to an initial time, wherein the phase of the FID signal in different intervals from a time 2nT to a time (2n+1)T in the time sequence is consistent with the dynamic process, n is a positive integer, and n is a plurality of consecutive positive integers from 1 to a target value, and T is a time interval from a time 0 in the time sequence to a time when the pulse is first applied;

[0110] The processing unit 1203 is used to discard the FID signal in the interval from time 0 to time T in the time sequence, and superimpose the FID signal except the interval from time 0 to time T in the time sequence to improve the resolution of the FID signal.

[0111] Optionally, the device 1200 further includes:

[0112] The conversion unit is used to convert the FID signal from a time domain signal to a frequency domain signal through fast Fourier transform.

[0113] Optionally, the time interval between each π pulse in the timing sequence is T.

[0114] It should be noted that the specific implementation methods and effects of the apparatus 1100 for processing nuclear magnetic signals and the apparatus 1200 for processing nuclear magnetic signals can be found in the above Figure 4 or Fig. 9 The relevant descriptions in the provided methods will not be repeated here.

[0115] The present application embodiment also provides an electronic device 1300, such as Fig.13 As shown, the electronic device 1300 includes a memory 1301 and a processor 1302:

[0116] The memory 1301 is used to store computer programs;

[0117] The processor 1302 is used to execute the above according to the computer program Figure 4 or Fig. 9 The method provided.

[0118] In addition, the present application also provides a computer-readable storage medium, the computer-readable storage medium is used to store a computer program, and the computer program is used to execute Figure 4 or Fig. 9 The method provided.

[0119] Through the description of the above implementation methods, it can be known that those skilled in the art can clearly understand that all or part of the steps in the above-mentioned embodiment method can be implemented by means of software plus a general hardware platform. Based on such an understanding, the technical solution of the present application can be embodied in the form of a software product, which can be stored in a storage medium, such as a read-only memory (ROM) / RAM, a magnetic disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network communication device such as a router) to execute the methods described in each embodiment of the present application or some parts of the embodiments.

[0120] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The device embodiment described above is only schematic, in which the modules described as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical modules, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the goals of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative work.

[0121] The above description is merely an exemplary embodiment of the present application and is not intended to limit the protection scope of the present application.

Claims

1. A method for processing nuclear magnetic resonance signals, characterized in that: The method comprises: By collecting nuclear magnetic signals, free induction decay FID signals are obtained; During the transverse relaxation process of the FID signal undergoing nuclear magnetic resonance, a π pulse in the CPMG pulse sequence is applied at a (2n-1)T moment in the time sequence, so that the FID signal generates a spin echo at a (2n-1)T moment in the time sequence, and a π pulse in the CPMG pulse sequence is applied at a 2nT moment in the time sequence, so that the phase of the FID signal is restored to an initial moment, wherein the phase of the FID signal in different intervals from a 2nT moment to a (2n+1)T moment in the time sequence is consistent with the dynamic process, n is a positive integer, and n is a plurality of consecutive positive integers from 1 to a target value, and T is a time interval from a 0 moment in the time sequence to a moment of first pulse application; The FID signals in the interval from time 0 to time T in the multiple time sequences and the FID signals in different intervals from time 2nT to time (2n+1)T are superimposed to improve the signal-to-noise ratio of the FID signals.

2. The method according to claim 1, characterized in that Before the FID signal performs a transverse relaxation process of nuclear magnetic resonance, the method further comprises: The FID signal is converted from a time domain signal to a frequency domain signal by fast Fourier transform.

3. The method according to claim 1, characterized in that The time interval between each π pulse in the timing sequence is T.

4. A method for processing nuclear magnetic resonance signals, characterized in that: The method comprises: By collecting nuclear magnetic signals, free induction decay FID signals are obtained; During the transverse relaxation process of the FID signal undergoing nuclear magnetic resonance, a π pulse in the CPMG pulse sequence is applied at a (2n-1)T moment in the time sequence, so that the FID signal generates a spin echo at a (2n-1)T moment in the time sequence, and a π pulse in the CPMG pulse sequence is applied at a 2nT moment in the time sequence, so that the phase of the FID signal is restored to an initial moment, wherein the phase of the FID signal in different intervals from a 2nT moment to a (2n+1)T moment in the time sequence is consistent with the dynamic process, n is a positive integer, and n is a plurality of consecutive positive integers from 1 to a target value, and T is a time interval from a 0 moment in the time sequence to a moment of first pulse application; The FID signal in the interval from time 0 to time T in the time sequence is discarded, and the FID signal outside the interval from time 0 to time T in the time sequence is superimposed to improve the resolution of the FID signal.

5. The method according to claim 4, characterized in that Before the FID signal performs a transverse relaxation process of nuclear magnetic resonance, the method further comprises: The FID signal is converted from a time domain signal to a frequency domain signal by fast Fourier transform.

6. The method according to claim 4, characterized in that The time interval between each π pulse in the timing sequence is T.

7. A device for processing nuclear magnetic resonance signals, characterized in that: The device comprises: An acquisition unit, used for acquiring a free induction decay (FID) signal by collecting a nuclear magnetic resonance signal; an applying unit, used for applying a π pulse in a CPMG pulse sequence at a (2n-1)T moment in a time sequence during a transverse relaxation process of nuclear magnetic resonance of the FID signal, so that the FID signal generates a spin echo at the (2n-1)T moment in the time sequence, and applying a π pulse in the CPMG pulse sequence at a 2nT moment in the time sequence, so that the phase of the FID signal is restored to an initial moment, wherein the phase of the FID signal in different intervals from the 2nT moment to the (2n+1)T moment in the time sequence is consistent with the dynamic process, n is a positive integer, and n is a plurality of consecutive positive integers from 1 to a target value, and T is a time interval from the 0 moment in the time sequence to the moment of first pulse application; The processing unit is used to superimpose the FID signals in the interval from time 0 to time T in the multiple time sequences and the FID signals in different intervals from time 2nT to time (2n+1)T to improve the signal-to-noise ratio of the FID signals.

8. A device for processing nuclear magnetic resonance signals, characterized in that: The device comprises: An acquisition unit, used for acquiring a free induction decay (FID) signal by collecting a nuclear magnetic resonance signal; an applying unit, used for applying a π pulse in a CPMG pulse sequence at a (2n-1)T moment in a time sequence during a transverse relaxation process of nuclear magnetic resonance of the FID signal, so that the FID signal generates a spin echo at the (2n-1)T moment in the time sequence, and applying a π pulse in the CPMG pulse sequence at a 2nT moment in the time sequence, so that the phase of the FID signal is restored to an initial moment, wherein the phase of the FID signal in different intervals from the 2nT moment to the (2n+1)T moment in the time sequence is consistent with the dynamic process, n is a positive integer, and n is a plurality of consecutive positive integers from 1 to a target value, and T is a time interval from the 0 moment in the time sequence to the moment of first pulse application; The processing unit is used to discard the FID signal in the interval from time 0 to time T in the time sequence, and superimpose the FID signal except the interval from time 0 to time T in the time sequence to improve the resolution of the FID signal.

9. An electronic device, characterized in that: The electronic device comprises a processor and a memory: The memory is used to store programs; The processor is used to execute the method according to any one of claims 1 to 3 or the method according to any one of claims 4 to 6 according to the program.

10. A storage medium, characterized in that: The storage medium is used to store a program, and the program runs on a processor to execute the method according to any one of claims 1 to 3 or the method according to any one of claims 4 to 6.

Images