WO2022000948A1 - 基于核磁共振***的物质测量方法及*** - Google Patents

基于核磁共振***的物质测量方法及*** Download PDF

Info

Publication number
WO2022000948A1
WO2022000948A1 PCT/CN2020/130163 CN2020130163W WO2022000948A1 WO 2022000948 A1 WO2022000948 A1 WO 2022000948A1 CN 2020130163 W CN2020130163 W CN 2020130163W WO 2022000948 A1 WO2022000948 A1 WO 2022000948A1
Authority
WO
WIPO (PCT)
Prior art keywords
magnetic resonance
nuclear magnetic
pulse sequence
substance
resonance pulse
Prior art date
Application number
PCT/CN2020/130163
Other languages
English (en)
French (fr)
Inventor
吴子岳
罗海
王伟谦
陈潇
叶洋
Original Assignee
无锡鸣石峻致医疗科技有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 无锡鸣石峻致医疗科技有限公司 filed Critical 无锡鸣石峻致医疗科技有限公司
Publication of WO2022000948A1 publication Critical patent/WO2022000948A1/zh
Priority to US18/068,133 priority Critical patent/US11766189B2/en

Links

Images

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves 
    • A61B5/055—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/448—Relaxometry, i.e. quantification of relaxation times or spin density
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/42—Detecting, measuring or recording for evaluating the gastrointestinal, the endocrine or the exocrine systems
    • A61B5/4222—Evaluating particular parts, e.g. particular organs
    • A61B5/4244—Evaluating particular parts, e.g. particular organs liver
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N24/00—Investigating or analyzing materials by the use of nuclear magnetic resonance, electron paramagnetic resonance or other spin effects
    • G01N24/08—Investigating or analyzing materials by the use of nuclear magnetic resonance, electron paramagnetic resonance or other spin effects by using nuclear magnetic resonance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/46—NMR spectroscopy
    • G01R33/4625—Processing of acquired signals, e.g. elimination of phase errors, baseline fitting, chemometric analysis
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/48—NMR imaging systems
    • G01R33/50—NMR imaging systems based on the determination of relaxation times, e.g. T1 measurement by IR sequences; T2 measurement by multiple-echo sequences
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/38—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field
    • G01R33/3808—Magnet assemblies for single-sided MR wherein the magnet assembly is located on one side of a subject only; Magnet assemblies for inside-out MR, e.g. for MR in a borehole or in a blood vessel, or magnet assemblies for fringe-field MR
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/48—NMR imaging systems
    • G01R33/54—Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console
    • G01R33/56—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution
    • G01R33/5608—Data processing and visualization specially adapted for MR, e.g. for feature analysis and pattern recognition on the basis of measured MR data, segmentation of measured MR data, edge contour detection on the basis of measured MR data, for enhancing measured MR data in terms of signal-to-noise ratio by means of noise filtering or apodization, for enhancing measured MR data in terms of resolution by means for deblurring, windowing, zero filling, or generation of gray-scaled images, colour-coded images or images displaying vectors instead of pixels
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/48—NMR imaging systems
    • G01R33/54—Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console
    • G01R33/56—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution
    • G01R33/561—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution by reduction of the scanning time, i.e. fast acquiring systems, e.g. using echo-planar pulse sequences
    • G01R33/5615—Echo train techniques involving acquiring plural, differently encoded, echo signals after one RF excitation, e.g. using gradient refocusing in echo planar imaging [EPI], RF refocusing in rapid acquisition with relaxation enhancement [RARE] or using both RF and gradient refocusing in gradient and spin echo imaging [GRASE]
    • G01R33/5617—Echo train techniques involving acquiring plural, differently encoded, echo signals after one RF excitation, e.g. using gradient refocusing in echo planar imaging [EPI], RF refocusing in rapid acquisition with relaxation enhancement [RARE] or using both RF and gradient refocusing in gradient and spin echo imaging [GRASE] using RF refocusing, e.g. RARE
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/48—NMR imaging systems
    • G01R33/54—Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console
    • G01R33/56—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution
    • G01R33/563—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution of moving material, e.g. flow contrast angiography
    • G01R33/56341—Diffusion imaging

Definitions

  • Embodiments of the present invention relate to a method and system for measuring a substance based on a nuclear magnetic resonance system.
  • relaxation In nuclear magnetic resonance phenomenon, relaxation refers to the phenomenon that when the nucleus resonates and is in a high energy state, when the radio frequency pulse stops, it will quickly return to the original low energy state.
  • the recovery process is called the relaxation process, which is an energy conversion process that takes a certain amount of time to reflect the interaction between the protons in the proton system and the environment around the protons.
  • all protons Under the action of the radio frequency pulse, all protons are in the same phase, they are all aligned in the same direction, and they precess around the external magnetic field with the same angular velocity (or angular frequency).
  • the protons in the same phase will gradually appear out of phase with each other, that is, out of phase.
  • the protons are gradually dispersed from the same phase and finally uniformly distributed, and their macroscopic performance is the change of their transverse magnetization vector M xy.
  • the transverse relaxation process is a process in which nuclei of the same kind exchange energy with each other, so it is also called a spin-spin relaxation process. Its transverse magnetization M xy decays with time due to the interaction between proton spins. After the action of the 90° pulse, there is the following relationship:
  • M xy (t) is the transverse magnetization at time t
  • M xymax is the transverse magnetization at time 0
  • t is the time calculated from the time when the transverse magnetization is M xymax
  • T 2 in the above formula (1) is called transverse relaxation time (transverse relaxation time), also known as spin-spin relaxation time.
  • S(t) is the signal intensity collected at time t
  • D is the diffusion coefficient of matter
  • b is usually called the b value
  • It is a coefficient determined by diffusion weighted imaging and diffusion tensor imaging to describe the comprehensive factors of diffusion gradient intensity, duration and application interval. The larger the b value is, the more sensitive it is to diffusion.
  • the nuclear magnetic resonance system to measure the T2 time constant and diffusion coefficient corresponding to each material component, the content of various components of the material can be measured, which can be used to analyze the special properties of the material or be used in clinical diagnosis.
  • D-T2 two-dimensional spectrum analysis method is a nuclear magnetic resonance technology widely used in material analysis.
  • the NMR sequence of the diffusion weighted module combined with the CPMG fast readout module is used to collect data.
  • the following sequences are commonly used, among which, a) For SE-CPMG sequence, i.e. spin-echo-based diffusion gradient encoding, followed by signal readout with ultrafast CPMG sequence.
  • DSE-CPMG sequence that is, diffusion gradient coding based on double-echo sequence, and signal readout with ultra-fast CPMG sequence, which can reduce the influence of low-speed liquid flow.
  • c) is the STE-CPMG sequence, that is, diffusion gradient coding based on stimulated echo sequence. This method can reduce the influence of T1 recovery. When the T1/T2 ratio of the detected object is small, using this sequence to measure the diffusion coefficient can improve the measurement accuracy. Spend.
  • the D-T2 two-dimensional spectral analysis method needs to adjust the b value of the diffusion weighting module, collect dozens to hundreds of sets of data, and then obtain the D-T2 of the substance through the two-dimensional inverse Laplace transform, that is, the diffusion coefficient-T2 Chi Helix time distribution map to obtain the composition information of the material.
  • the measurement sequence of D-T2 two-dimensional spectrum analysis is shown in Figure 1.
  • Embodiments of the present invention provide a method and system for measuring a substance based on a nuclear magnetic resonance system, so as to solve or improve the technical problem of processing a large amount of data in the prior art.
  • an embodiment of the present invention provides a method for measuring a substance based on a nuclear magnetic resonance system, including: collecting several sets of echo signals of a nuclear magnetic resonance pulse sequence with different echo intervals from a substance to be measured, and processing to obtain several sets of echo signals with transverse relaxation. and the signal of diffusion attenuation; and fitting the signal with transverse relaxation and diffusion attenuation in combination with prior knowledge to obtain the diffusion coefficient, transverse relaxation time or/and content weight of the components in the tested substance.
  • the nuclear magnetic resonance pulse sequence is a CPMG sequence.
  • the gradient system of the nuclear magnetic resonance system includes a unilateral magnet, and a natural gradient magnetic field formed by the unilateral magnet
  • the signal can be encoded by the diffusion effect; the echo interval and the b value satisfy the following relationship:
  • G 0 is the magnetic field gradient
  • ⁇ is the gyromagnetic ratio
  • b is the b value
  • t E is the echo interval.
  • the method collects several sets of nuclear magnetic resonance pulse sequence echo signals with different echo intervals from the substance to be tested, and processes them to obtain several sets of echo signals.
  • Signals with transverse relaxation and diffusion attenuation including: representing each group of NMR pulse sequence echo signals collected as a four-dimensional array s(b,m,x,p), where the first dimension b is the corresponding b The echo signal of the NMR pulse sequence with the echo interval under the value, the second dimension m is the length of the echo chain, the third dimension x is the average number of times, and the fourth dimension p is the number of sampling points of a single readout data; where, m, Both x and p are positive integers greater than zero;
  • the signal with transverse relaxation and diffusion attenuation is fitted with prior knowledge to obtain the measured substance.
  • Diffusion coefficients, transverse relaxation times or/and content weights of components including:
  • n is a positive integer greater than or equal to zero
  • a 3n+1 is the weight of the contained substance
  • a 3n+2 is the reciprocal of the T2 relaxation time constant of the substance
  • a 3n+3 is the substance diffusion coefficient
  • k is the noise
  • s is the echo signal of the nuclear magnetic resonance pulse sequence
  • ⁇ represents the two-norm
  • the parameter indices LB and UB are the lower and upper limits obtained from prior knowledge, respectively.
  • an embodiment of the present invention further provides a system for implementing the measurement method, comprising:
  • the console is used to send an instruction to transmit a nuclear magnetic resonance pulse sequence, receive an echo signal of the nuclear magnetic resonance pulse sequence, and analyze and process the echo signal to obtain a signal with transverse relaxation and diffusion attenuation.
  • the signals of relaxation and diffusion decay are fitted to obtain the diffusion coefficient, transverse relaxation time or/and content weight of the components in the tested substance;
  • a magnet module for generating a gradient magnetic field for the substance under test
  • the nuclear magnetic resonance system is used for receiving and transmitting the nuclear magnetic resonance pulse sequence instruction, and according to the transmitting nuclear magnetic resonance pulse sequence instruction, transmitting the nuclear magnetic resonance pulse sequence for applying to the measured substance; echo signals and feed back the echo signals of the nuclear magnetic resonance pulse sequence to the console.
  • the nuclear magnetic resonance system includes:
  • the nuclear magnetic resonance spectrometer is used for receiving and transmitting the nuclear magnetic resonance pulse sequence instruction, and transmitting the nuclear magnetic resonance pulse sequence according to the transmitting nuclear magnetic resonance pulse sequence instruction; for receiving the echo signal of the nuclear magnetic resonance pulse sequence fed back by the radio frequency system to the The console feeds back the echo signal of the nuclear magnetic resonance pulse sequence; and
  • a radio frequency system for processing the nuclear magnetic resonance pulse sequence so as to be applied to the substance to be tested, for processing the echo signal of the nuclear magnetic resonance pulse sequence for feedback to the console, for switching the mode of transmitting the nuclear magnetic resonance pulse sequence and The echo signal mode of receiving the nuclear magnetic resonance pulse sequence; used for transmitting the nuclear magnetic resonance pulse sequence or receiving the echo signal of the nuclear magnetic resonance pulse sequence.
  • the radio frequency system includes:
  • a transceiver conversion module communicated with the nuclear magnetic resonance spectrometer, and used for switching the mode of transmitting the nuclear magnetic resonance pulse sequence and the mode of receiving the echo signal of the nuclear magnetic resonance pulse sequence;
  • the radio frequency coil communicates with the transceiver conversion module.
  • the radio frequency coil is used to generate the excitation center frequency for the measured substance; when the transceiver conversion module is switched to receive the nuclear magnetic resonance pulse sequence In the echo signal mode, the radio frequency coil is used to receive the echo signal of the nuclear magnetic resonance pulse sequence.
  • the transceiving conversion module is a transceiving conversion switch.
  • the magnet module includes a single-sided magnet.
  • the method and system for measuring a substance based on a nuclear magnetic resonance system according to the embodiments of the present invention, several sets of echo signals of nuclear magnetic resonance pulse sequences with different echo intervals are collected from the measured substance and processed to obtain several sets of echo signals with transverse relaxation and diffusion attenuation.
  • the signal with the transverse relaxation and diffusion decay is fitted with the prior knowledge to obtain the diffusion coefficient, transverse relaxation time or/and content weight of the components in the measured substance. Obviously, it is not necessary to collect a large amount of data. In this way, the measurement of the diffusion coefficient, transverse relaxation time or/and content of the components in the measured substance can be realized, which can be applied to the analysis of substance properties or clinical diagnosis.
  • Figure 1 is a schematic diagram of the structure of the D-T2 two-dimensional spectrum analysis measurement sequence.
  • FIG. 2 is a schematic diagram of method steps according to an embodiment of the present invention.
  • FIG. 3 is a schematic structural diagram of a system principle according to an embodiment of the present invention.
  • FIG. 4 is a diagram of a magnetic resonance pulse sequence according to an embodiment of the present invention.
  • FIG. 5 is a fitting curve diagram of two sets of signals with different t E values collected in the embodiment of the present invention.
  • Embodiments of the present invention provide a substance measurement method and system based on a nuclear magnetic resonance system, so as to solve or improve the problem of large amount of data processing in the prior art.
  • the method and the system are based on the same inventive concept. Since the principles of the method and the system for solving problems are similar, the implementation of the system and the method can be referred to each other, and the repetition will not be repeated.
  • an embodiment of the present invention provides a method for measuring a substance based on a nuclear magnetic resonance system, including: collecting several sets of echo signals of nuclear magnetic resonance pulse sequences with different echo intervals from a substance to be measured, and processing to obtain several sets of echo signals with lateral Signals of relaxation and diffusion decay; fit the signal with transverse relaxation and diffusion decay in combination with prior knowledge to obtain the diffusion coefficient, transverse relaxation time or/and content weight of components in the tested substance, and solve or The problem of dealing with a large amount of data in the prior art is improved, so that it can be applied to the analysis of material properties or clinical diagnosis.
  • the method of the embodiment of the present invention obtains several groups of signals with transverse relaxation and diffusion attenuation by collecting several groups (optionally less than ten groups) of nuclear magnetic resonance pulse sequence echo signals with different echo intervals;
  • the signal with transverse relaxation and diffusion decay is fitted and combined with the prior knowledge of the components in the measured substance, and the transverse relaxation time constant, diffusion coefficient and/or component content in the substance are estimated to be obtained; in which the signal is fitted This can be achieved by building a signal processing model.
  • the nuclear magnetic resonance pulse sequence is a CPMG sequence, as shown in FIG. 4 .
  • the gradient system of the nuclear magnetic resonance system includes a unilateral magnet, and the natural gradient magnetic field formed by the unilateral magnet can encode the signal with diffusion effect; the echo interval and the b value satisfy the following relationship:
  • G 0 is the magnetic field gradient
  • ⁇ is the gyromagnetic ratio
  • b is the b value
  • t E is the echo interval.
  • the gradient system of the nuclear magnetic resonance system includes a single-sided magnet, and the single-sided magnet has a constant gradient field. Therefore, when the gradient system of the nuclear magnetic resonance system includes a single-sided magnet, G 0 and ⁇ are fixed values. At this time, the b value is only related to the echo interval t E , so that the b value can be adjusted by controlling the size of t E.
  • the third dimension x is the average number of times, that is, in actual use, multiple acquisitions are required for averaging to improve the signal-to-noise ratio, and the average number of times x is the required number of acquisitions for the purpose of improving the signal-to-noise ratio.
  • the four-dimensional array s(b,m,x,p) signal becomes a two-dimensional signal s(b,m), and the two-dimensional signal s(b,m) is a different echo interval
  • the signal attenuation curve of the intensity changing with time collected under time is the signal with transverse relaxation and diffusion attenuation, for example, s(1,:) is a signal intensity corresponding to the first echo interval that decays with the transverse relaxation time the curve.
  • n is a positive integer greater than or equal to zero
  • a 3n+1 is the weight of the contained substance
  • a 3n+2 is the reciprocal of the T2 relaxation time constant of the substance
  • a 3n+3 is the substance diffusion coefficient
  • k is the noise
  • s is the echo signal of the nuclear magnetic resonance pulse sequence
  • ⁇ represents the two-norm
  • the parameter indices LB and UB are the lower and upper limits obtained from prior knowledge, respectively.
  • k is a noise-related parameter, but it can also be a noise-related expression or a noise-related probability model.
  • a 1 and a 4 are the content weights of substances 1 and 2, respectively, a 2 and a 5 are the reciprocals of T 2 relaxation times of substances 1 and 2 , a 3 and a 6 are the diffusion coefficients of substances 1 and 2, k is the noise mean, s is the measured magnetic resonance signal, and ⁇ represents the second norm.
  • the content weight, T 2 relaxation time reciprocal and diffusion coefficient of the first substance are a 1 , a 2 and a 3 respectively ;
  • the content weight, T 2 relaxation time reciprocal and diffusion coefficient of the second substance are a 4 , respectively , a 5 and a 6 ; when there are multiple substance components, and so on.
  • the acquired signal s can be represented as a four-dimensional array, wherein the first dimension is the acquisition of different values of b, corresponding to different echo intervals, which is 2 in this example.
  • the second dimension is the length of the echo chain; the third dimension is the average number of times; the fourth dimension is the number of sampling points of a single readout data.
  • the fourth dimension is Fourier transformed, the low-frequency part is averaged, and then the third dimension is averaged to obtain two attenuation curves with different b values (echo interval).
  • the signal s measured at two different echo intervals is brought into (6), and a 1 -a can be determined according to the priori conditions such as the diffusion coefficients of the two substances to be determined and the approximate upper and lower limits of the relaxation time of T 2 . 6 and the range of the fitting result of k, so as to accurately solve the unknowns in the formula.
  • the diffusion coefficient, T 2 relaxation time constant and fat content of the human liver were measured.
  • the magnetic field of the unilateral magnet of the nuclear magnetic resonance system is 0.08T, and the constant gradient field is about 1.1T/m.
  • Two groups of different echo intervals were measured, 500us and 1100us respectively, the echo chain length was 256, 64 times on average, and 64 points were collected for each echo.
  • the repetition time TR was 1000 ms, and the total acquisition time was about 2 minutes.
  • the fat proportion is 13.5212%
  • the fat T 2 115ms
  • the liver tissue T 2 39.9ms
  • the fat diffusion coefficient 2.0e -5 mm 2 /s the liver tissue diffusion coefficient 1.2109e -3 mm 2 /s.
  • the method of the embodiment of the present invention only adjusts the echo interval by using the traditional CPMG sequence, the signal processing after the measurement sequence is simple, and the measurement of the substance content can be realized without collecting a large amount of data; thus the method of the embodiment of the present invention can realize the measurement of the substance content. It has the advantages of short acquisition time, reduced storage requirements, low data processing time, stable fitting results, and high repeatability.
  • An embodiment of the present invention further provides a system for implementing the above measurement method, comprising:
  • the console is used to send an instruction to transmit a nuclear magnetic resonance pulse sequence, receive an echo signal of the nuclear magnetic resonance pulse sequence, and analyze and process the echo signal to obtain a signal with transverse relaxation and diffusion attenuation.
  • the signals of relaxation and diffusion decay are fitted to obtain the diffusion coefficient, transverse relaxation time or/and content weight of the components in the tested substance;
  • a magnet module for generating a gradient magnetic field for the substance under test
  • the nuclear magnetic resonance system is used for receiving and transmitting the nuclear magnetic resonance pulse sequence instruction, and according to the transmitting nuclear magnetic resonance pulse sequence instruction, transmitting the nuclear magnetic resonance pulse sequence for applying to the measured substance; echo signals and feed back the echo signals of the nuclear magnetic resonance pulse sequence to the console.
  • the console sends an instruction to transmit a magnetic resonance pulse sequence to a nuclear magnetic resonance spectrometer, and the nuclear magnetic working spectrometer transmits a magnetic resonance pulse sequence according to the instruction to transmit a magnetic resonance pulse sequence.
  • the magnetic resonance pulse sequence is processed by the radio frequency power amplifier and then switched to the transmitting magnetic resonance pulse sequence mode through the transceiver conversion module (such as the transceiver conversion switch), and the processed magnetic resonance pulse sequence is sent to the radio frequency coil, and the radio frequency coil is in the magnet.
  • the processed magnetic resonance pulse sequence acts on the measured substance; then, the transceiver conversion module switches to receive the echo signal mode of the magnetic resonance pulse sequence, and the transceiver conversion module passes the radio frequency coil.
  • the echo signal of the magnetic resonance pulse sequence of the substance to be tested is received, processed by the preamplifier, and then fed back to the nuclear magnetic resonance instrument; the nuclear magnetic resonance instrument is transmitted to the console; two or more test objects with different echo intervals are collected by the above method.
  • the signals of relaxation and diffusion decay are fitted to obtain the diffusion coefficient, transverse relaxation time or/and content weight of the components in the measured substance.
  • the nuclear magnetic resonance system includes:
  • the nuclear magnetic resonance spectrometer is used for receiving and transmitting the nuclear magnetic resonance pulse sequence instruction, and transmitting the nuclear magnetic resonance pulse sequence according to the transmitting nuclear magnetic resonance pulse sequence instruction; for receiving the echo signal of the nuclear magnetic resonance pulse sequence fed back by the radio frequency system to the The console feeds back the echo signal of the nuclear magnetic resonance pulse sequence; and
  • a radio frequency system for processing the nuclear magnetic resonance pulse sequence so as to be applied to the substance to be tested, for processing the echo signal of the nuclear magnetic resonance pulse sequence for feedback to the console, for switching the mode of transmitting the nuclear magnetic resonance pulse sequence and The echo signal mode of receiving the nuclear magnetic resonance pulse sequence; used for transmitting the nuclear magnetic resonance pulse sequence or receiving the echo signal of the nuclear magnetic resonance pulse sequence.
  • the radio frequency system includes:
  • a transceiver conversion module communicated with the nuclear magnetic resonance spectrometer, and used for switching the mode of transmitting the nuclear magnetic resonance pulse sequence and the mode of receiving the echo signal of the nuclear magnetic resonance pulse sequence;
  • the radio frequency coil communicates with the transceiver conversion module.
  • the radio frequency coil is used to generate the excitation center frequency for the measured substance; when the transceiver conversion module is switched to receive the nuclear magnetic resonance pulse sequence In the echo signal mode, the radio frequency coil is used to receive the echo signal of the nuclear magnetic resonance pulse sequence.
  • the transceiving conversion module is a transceiving conversion switch.
  • the magnet module includes a single-sided magnet.
  • the magnet module of this embodiment adopts a single-sided magnet, and no additional gradient system is required, thereby reducing the complexity and hardware cost of the system.
  • the system of the embodiment of the present invention collects the echo signals of the magnetic resonance pulse sequences of two or more measured substances with different echo intervals; after the collection is completed, the console analyzes and processes the echo signals to obtain a Signals of lateral relaxation and diffusion attenuation, and fitting the signals with lateral relaxation and diffusion attenuation to obtain the diffusion coefficient, lateral relaxation time or/and content weight of the components in the measured substance; signal processing is simple and does not require Substance content can be measured by collecting a large amount of data; thus, the system of the embodiment of the present invention has the advantages of short acquisition time, reduced storage requirements, low data processing time, stable fitting results, and high repeatability.
  • embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.
  • computer-usable storage media including, but not limited to, disk storage, CD-ROM, optical storage, etc.
  • These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory result in an article of manufacture comprising instruction means, the instructions
  • the apparatus implements the functions specified in the flow or flow of the flowcharts and/or the block or blocks of the block diagrams.

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • High Energy & Nuclear Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Pathology (AREA)
  • General Health & Medical Sciences (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Engineering & Computer Science (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Animal Behavior & Ethology (AREA)
  • Surgery (AREA)
  • Molecular Biology (AREA)
  • Medical Informatics (AREA)
  • Biophysics (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Radiology & Medical Imaging (AREA)
  • Analytical Chemistry (AREA)
  • Immunology (AREA)
  • Biochemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Gastroenterology & Hepatology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Signal Processing (AREA)
  • Endocrinology (AREA)
  • Physiology (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)

Abstract

基于核磁共振***的物质测量方法及***，用以解决或改善现有技术处理数据量大的技术问题；其方法包括：向被测物质采集几组具有不同回波间隔的核磁共振脉冲序列回波信号并处理得到几组带有横向弛豫及扩散衰减的信号；结合先验知识对带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重；其***包括：控制台、磁体模块以及核磁共振***。该测量方法及***通过采集几组具有不同回波间隔的核磁共振脉冲序列回波信号进行拟合处理，不需采集大量数据即可实现对被测物质中成分的扩散系数、横向弛豫时间或/和含量的测量。

Description

基于核磁共振***的物质测量方法及*** 技术领域
本发明实施例涉及基于核磁共振***的物质测量方法及***。
背景技术
在核磁共振现象中，弛豫是指原子核发生共振且处在高能状态时，当射频脉冲停止后，将迅速恢复到原来低能状态的现象。恢复的过程即称为弛豫过程，它是一个能量转换过程，需要一定的时间反映了质子***中质子之间和质子周围环境之间的相互作用。在射频脉冲的作用下，所有质子的相位都相同，它们都沿相同的方向排列，以相同的角速度(或角频率)绕外磁场进动。当射频脉冲停止后，同相位的质子彼此之间将逐渐出现相位差，即失相位。
质子由同相位逐渐分散最终均匀分布，其宏观表现为其横向磁化强度矢量M xy的变化。从物理学的观点看，横向弛豫过程是同种核相互交换能量的过程，故又称为自旋-自旋弛豫过程。由于质子自旋间的相互作用，其横向磁化强度M xy随时间衰减。而在90°脉冲作用后，有如下关系：
Figure PCTCN2020130163-appb-000001
式(1)中，M xy(t)为时间t时横向磁化强度，M xymax为时间0时的横向磁化强度，t为从横向磁化强度为M xymax时开始计算的时间；
上式(1)中的T 2称为横向弛豫时间(transverse relaxation time)又称自旋-自旋弛豫时间。
生物组织内的水分子因受周围介质的约束，核磁共振信号被激发后，水分子在梯度磁场方向上的扩散运动将造成核磁共振信号的衰减，如果水分子在梯度磁场方向上扩散越自由，则在梯度磁场施加期间扩散距离越大，经历的磁场 变化也越大，组织信号衰减越明显。类似于T 2衰减，扩散导致的衰减可由下式(2)描述：
S(t)＝S maxe -Dbt      (2)
由于在核磁共振中，采集到的信号强弱与横向磁化矢量成正比关系，综合考虑T 2与扩散衰减，则信号强弱与时间关系为：
Figure PCTCN2020130163-appb-000002
式(2)和(3)中，S(t)为时间为t时采集到的信号强度，S max为时间t＝0时的信号强度，D为物质扩散系数，b通常称为b值，是扩散加权成像和扩散张量成像描述扩散梯度强度、持续时间以及施加间隔的综合因素所决定的系数，b值越大，对扩散越敏感。
因此，采用核磁共振***通过测量每种物质成分对应的T2时间常数和扩散系数，可实现对物质的多种成分含量的测量，可用于分析物质的特殊性质或者应用于临床诊断。
D-T2二维谱分析法是目前广泛应用于物质分析的核磁共振技术，一般采用扩散加权模块结合CPMG快速读出模块的核磁共振序列采集数据，常用的有如下几种序列，其中，a)为SE-CPMG序列，即基于自旋回波进行扩散梯度编码，然后用超快速的CPMG序列进行信号读出。b)为DSE-CPMG序列，即基于双回波序列进行扩散梯度编码，同样用超快速的CPMG序列进行信号读出，该方法能降低低速液体流动带来的影响。c)为STE-CPMG序列，即基于受激回波序列进行扩散梯度编码，该方法能降低T1恢复的影响，当被检测物体的T1/T2比较小时，用该序列测量扩散系数可以提升测量准确度。
D-T2二维谱分析法需要调整扩散加权模块的b值，采集数十到数百组数据，然后通过二维逆拉普拉斯变换求出物质的D-T2，即扩散系数-T2驰豫时间分布图，从而得到物质的成分信息。D-T2二维谱分析测量序列如图1所示。
其缺陷在于：1)需要采集大量的数据，采集时间长，数据储存耗费资源较多；由于数据量很大，数据处理对硬件要求很高，而且往往需要对数据进行预处理，运算时间长；2)拉普拉斯逆变换本身对噪音比较敏感，拟合结果不稳定，算法鲁棒性差。
发明内容
本发明实施例提供基于核磁共振***的物质测量方法及***，用以解决或改善现有技术处理数据量大的技术问题。
第一方面，本发明实施例提供基于核磁共振***的物质测量方法，包括：向被测物质采集几组具有不同回波间隔的核磁共振脉冲序列回波信号并处理得到几组带有横向弛豫及扩散衰减的信号；结合先验知识对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重。
结合第一方面，在第一种可能的实现方式中，所述核磁共振脉冲序列为CPMG序列。
结合第一方面或第一方面的第一种可能的实现方式，在第二种可能的实现方式中，所述核磁共振***的梯度***包括单边磁体，所述单边磁体形成的天然梯度磁场能够对信号做扩散效应编码；所述回波间隔与b值满足如下关系式：
Figure PCTCN2020130163-appb-000003
式(4)中，G 0为磁场梯度；γ为旋磁比；b为b值；t E为回波间隔。
结合第一方面的第二种可能的实现方式，在第三种可能的实现方式中，所述向被测物质采集几组具有不同回波间隔的核磁共振脉冲序列回波信号并处理得到几组带有横向弛豫及扩散衰减的信号，包括：将采集到的每组核磁共振脉冲序列回波信号表示为四维数组s(b,m,x,p),其中，第一维b为对应b值下的回波间隔的核磁共振脉冲序列回波信号，第二维m为回波链长度，第三维x为平均 次数，第四维p为单次读出数据的采样点数；其中，m,x和p均为大于零的正整数；
对所有的四维数组s(b,m,x,p)的第四维p做傅里叶变换后取低频部分作为平均值，对第三维x取平均后，得到几组带有横向弛豫及扩散衰减的信号。
结合第一方面的第三种可能的实现方式，在第四种可能的实现方式中，所述结合先验知识对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重，包括：
使用式(5)对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重：
Figure PCTCN2020130163-appb-000004
约束条件，
Figure PCTCN2020130163-appb-000005
其中，n为大于或等于零的正整数，a 3n+1为所含物质的权重，a 3n+2为物质的T2弛豫时间常数倒数，a 3n+3为物质扩散系数，k为噪声，s为核磁共振脉冲序列回波信号，‖‖表示二范数；约束条件中参数角标LB、UB分别为由先验知识取得的下限和上限。
第二方面，本发明实施例还提供一种实现所述测量方法的***，包括
控制台，用于发送发射核磁共振脉冲序列指令，接收核磁共振脉冲序列的回波信号，对所述回波信号分析处理得到带有横向弛豫及扩散衰减的信号，对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重；
磁体模块，用于对被测物质产生梯度磁场；以及
核磁共振***，用于接收发射核磁共振脉冲序列指令，并根据所述发射核 磁共振脉冲序列指令发射用于施加于被测物质的核磁共振脉冲序列；用于接收被测物质的核磁共振脉冲序列的回波信号并向所述控制台反馈所述核磁共振脉冲序列的回波信号。
结合第二方面，在第一种可能的实现方式中，所述核磁共振***包括：
核磁共振谱仪，用于接收发射核磁共振脉冲序列指令，并根据所述发射核磁共振脉冲序列指令发射核磁共振脉冲序列；用于接收射频***反馈的核磁共振脉冲序列的回波信号并向所述控制台反馈所述核磁共振脉冲序列的回波信号；以及
射频***，用于对核磁共振脉冲序列处理以便于施加于被测物质，用于对所述核磁共振脉冲序列的回波信号处理以便于向控制台反馈，用于切换发射核磁共振脉冲序列模式和接收核磁共振脉冲序列的回波信号模式；用于发射核磁共振脉冲序列或接收核磁共振脉冲序列的回波信号。
结合第二方面的第一种可能的实现方式，在第二种可能的实现方式中，所述射频***包括：
收发转换模块，与核磁共振谱仪通讯，用于切换发射核磁共振脉冲序列模式和接收核磁共振脉冲序列的回波信号模式；以及
射频线圈，与收发转换模块通讯，当收发转换模块切换为发射核磁共振脉冲序列模式时，所述射频线圈用于对被测物质产生激发中心频率；当收发转换模块切换为接收核磁共振脉冲序列的回波信号模式时，所述射频线圈用于接收核磁共振脉冲序列的回波信号。
结合第二方面的第二种可能的实现方式，在第三种可能的实现方式中，所述收发转换模块为收发转换开关。
结合第二方面的第三种可能的实现方式，在第四种可能的实现方式中，所述磁体模块包括单边磁体。
本发明实施例的基于核磁共振***的物质测量方法及***，通过向被测物质采集几组具有不同回波间隔的核磁共振脉冲序列回波信号并处理得到几组带有横向弛豫及扩散衰减的信号；结合先验知识对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重，显然，不需采集大量数据即可实现对被测物质中成分的扩散系数、横向弛豫时间或/和含量的测量，从而可应用于物质性质的分析或者临床诊断。
附图说明
为了更清楚地说明本发明实施例中的技术方案，下面对实施例描述中所需要使用的附图作简要介绍。
图1是D-T2二维谱分析测量序列的结构示意图。
图2是本发明实施例的方法步骤示意图。
图3是本发明实施例的***原理结构示意图。
图4是本发明实施例的磁共振脉冲序列图。
图5是本发明实施例中采集到的两组不同t E值的信号的拟合曲线图。
具体实施方式
为了使本发明的目的、技术方案和优点更加清楚，下面将结合附图对本发明实施例作进一步地详细描述。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。
本发明实施例提供基于核磁共振***的物质测量方法及***，用以解决或改善现有技术处理数据量大的问题。其中，方法和***是基于同一发明构思的，由于方法及***解决问题的原理相似，因此***与方法的实施可以相互参见，重复之处不再赘述。
本发明中所涉及的多个，是指两个或两个以上。另外，在本发明的描述中，“第一”、“第二”等词汇，仅用于区分描述的目的，而不能理解为指示或暗示相对重要性，也不能理解为指示或暗示顺序。
参阅图2所示，本发明实施例提供基于核磁共振***的物质测量方法，包括：向被测物质采集几组具有不同回波间隔的核磁共振脉冲序列回波信号并处理得到几组带有横向弛豫及扩散衰减的信号；结合先验知识对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重，解决或改善了现有技术处理数据量大的问题，从而可应用于物质性质的分析或者临床诊断。
本发明实施例的所述方法通过采集几组(可选小于十组)具有不同回波间隔的核磁共振脉冲序列回波信号处理得到几组带有横向弛豫及扩散衰减的信号；对所述带有横向弛豫及扩散衰减的信号进行拟合结合被测物质中组分的先验知识，估算得到横向驰豫时间常数、扩散系数和/或物质中组分含量；其中对信号进行拟合可以通过建立信号处理模型的方式来实现。
为了使本发明实施例的方法可以同时拟合出两种物质的扩散系数、横向驰豫时间常数以及物质含量，提供如下的可选实施方式。
可选地，所述核磁共振脉冲序列为CPMG序列，如图4所示。
所述核磁共振***的梯度***包括单边磁体，所述单边磁体形成的天然梯度磁场能够对信号做扩散效应编码；所述回波间隔与b值满足如下关系式：
Figure PCTCN2020130163-appb-000006
式(4)中，G 0为磁场梯度；γ为旋磁比；b为b值；t E为回波间隔。
可选地，所述核磁共振***的梯度***包括单边磁体，单边磁体具有恒定的梯度场，因此，核磁共振***的梯度***包括单边磁体时，G 0，γ为固定值。此时，b值仅与回波间隔t E有关，从而可以通过控制t E的大小来达到对b值的调 整。
为了便于计算机的自动化处理，可选地，所述向被测物质采集几组具有不同回波间隔的核磁共振脉冲序列回波信号并处理得到几组带有横向弛豫及扩散衰减的信号，包括：将采集到的每组核磁共振脉冲序列回波信号表示为四维数组s(b,m,x,p),其中，第一维b为对应b值下的回波间隔的核磁共振脉冲序列回波信号，第二维m为回波链长度，第三维x为平均次数，第四维p为单次读出数据的采样点数；其中，m,x和p均为大于零的正整数；
其中，第三维x为平均次数，即实际使用时需要多次采集进行平均来提高信噪比，平均次数x即出于提高信噪比的目的，所需要的采集次数。
对所有的四维数组s(b,m,x,p)的第四维p做傅里叶变换后取低频部分作为平均值，对第三维x取平均后，得到几组带有横向弛豫及扩散衰减的信号。
其中，在进行傅里叶变换以及平均以后，四维数组s(b,m,x,p)信号变二维信号s(b,m),二维信号s(b,m)为不同回波间隔时间下采到的强度随时间变化的信号衰减曲线即带有横向弛豫及扩散衰减的信号，如s(1，：)为第一个回波间隔对应的一条信号强度随横向弛豫时间衰减的曲线。
进一步的，所述结合先验知识对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重，包括：
使用式(5)对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重：
Figure PCTCN2020130163-appb-000007
约束条件，
Figure PCTCN2020130163-appb-000008
其中，n为大于或等于零的正整数，a 3n+1为所含物质的权重，a 3n+2为物质的T2弛豫时间常数倒数，a 3n+3为物质扩散系数，k为噪声，s为核磁共振脉冲 序列回波信号，‖‖表示二范数；约束条件中参数角标LB、UB分别为由先验知识取得的下限和上限。
其中，k为与噪声相关的参数，但是也可以是噪声相关的表达式或者噪声相关的概率模型。
以下具体举例说明。
以测定两种物质组分为例，即n分别取0和1，式(5)可以简化为如下公式(6)
Figure PCTCN2020130163-appb-000009
约束条件
Figure PCTCN2020130163-appb-000010
角标LB,UB分别为取值的下限和上限。
其中，a 1与a 4分别为物质1和2的含量权重，a 2与a 5为物质1与2的T 2弛豫时间倒数，a 3与a 6为物质1与2的扩散系数,k为噪声均值，s为测量到的磁共振信号，‖‖表示二范数。
即第一种物质的含量权重、T 2弛豫时间倒数和扩散系数分别为a 1、a 2和a 3；第二种物质的含量权重、T 2弛豫时间倒数和扩散系数分别为a 4、a 5和a 6；当具有多种物质组分时，依此类推。
通过设置不同的t E，采集得到信号s可以表示为一个四维数组，其中第一维为b不同取值的采集，对应不同的回波间隔，此例中为2。第二维为回波链长度；第三维为平均次数；第四维为单次读出数据的采样点数。
对第四维做傅里叶变换后取低频部分做平均值，再对第三维取平均后，得 到b值(回波间隔时间)不同的两条衰减曲线。将两次不同回波间隔下测量的信号s带入(6)，根据待求的两种物质扩散系数以及T 2弛豫时间的大致取值上下限等先验条件，可确定a 1-a 6以及k的拟合结果范围，从而精确求解式中未知量。
具体如图5所示，该示例中，测量了人体肝脏的扩散系数、T 2弛豫时间常数以及脂肪含量。核磁共振***的单边磁体磁场为0.08T，恒定梯度场约1.1T/m。测量了两组不同的回波间隔，分别为500us和1100us，回波链长度为256，平均64次，每个回波采集64个点。重复时间TR为1000ms，总采集时间约2分钟。结合肝脏组织与脂肪的先验知识对a 1～？ 6以及k进行上下限的设定后拟合得到脂肪比例13.5212％，脂肪T 2＝115ms，肝脏组织T 2＝39.9ms，脂肪扩散系数2.0e -5mm 2/s，肝脏组织扩散系数1.2109e -3mm 2/s。
可见，本发明实施例的方法使用传统CPMG序列仅对回波间隔进行调整，测量序列之后的信号处理简单，不需采集大量数据，即可实现对物质含量的测量；从而本发明实施例的方法具有采集时间短、降低储存需求数据处理耗时低以及拟合结果稳定、可重复性高等优点。
本发明实施例还提供一种实现上述测量方法的***，包括
控制台，用于发送发射核磁共振脉冲序列指令，接收核磁共振脉冲序列的回波信号，对所述回波信号分析处理得到带有横向弛豫及扩散衰减的信号，对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重；
磁体模块，用于对被测物质产生梯度磁场；以及
核磁共振***，用于接收发射核磁共振脉冲序列指令，并根据所述发射核磁共振脉冲序列指令发射用于施加于被测物质的核磁共振脉冲序列；用于接收被测物质的核磁共振脉冲序列的回波信号并向所述控制台反馈所述核磁共振脉冲序列的回波信号。
如图3所示的，一种实现上述测量方法的***工作过程如下：控制台发送发射磁共振脉冲序列指令至核磁共振谱仪，核磁工作谱仪根据发射磁共振脉冲序列指令发射磁共振脉冲序列，如CPMG序列；磁共振脉冲序列经过射频功率放大器处理后通过收发转换模块(如收发转换开关)切换为发射磁共振脉冲序列模式将处理后的磁共振脉冲序列发送至射频线圈，射频线圈在磁体模块(如单边永磁体)的梯度磁场下将处理后的磁共振脉冲序列作用于被测物质；而后，收发转换模块切换为接收磁共振脉冲序列的回波信号模式，收发转换模块通过射频线圈接收被测物质的磁共振脉冲序列的回波信号并通过前置放大器处理后反馈至核磁共振仪；核磁共振仪传输至控制台；采用上述方式采集回波间隔不同的两个及以上的被测物质的磁共振脉冲序列的回波信号；依此类推，直至全部采集完成；采集完成后，控制台对回波信号分析处理得到带有横向弛豫及扩散衰减的信号，对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重。
可选地，所述核磁共振***包括：
核磁共振谱仪，用于接收发射核磁共振脉冲序列指令，并根据所述发射核磁共振脉冲序列指令发射核磁共振脉冲序列；用于接收射频***反馈的核磁共振脉冲序列的回波信号并向所述控制台反馈所述核磁共振脉冲序列的回波信号；以及
射频***，用于对核磁共振脉冲序列处理以便于施加于被测物质，用于对所述核磁共振脉冲序列的回波信号处理以便于向控制台反馈，用于切换发射核磁共振脉冲序列模式和接收核磁共振脉冲序列的回波信号模式；用于发射核磁共振脉冲序列或接收核磁共振脉冲序列的回波信号。
可选地，所述射频***包括：
收发转换模块，与核磁共振谱仪通讯，用于切换发射核磁共振脉冲序列模式和接收核磁共振脉冲序列的回波信号模式；以及
射频线圈，与收发转换模块通讯，当收发转换模块切换为发射核磁共振脉冲序列模式时，所述射频线圈用于对被测物质产生激发中心频率；当收发转换模块切换为接收核磁共振脉冲序列的回波信号模式时，所述射频线圈用于接收核磁共振脉冲序列的回波信号。
可选地，所述收发转换模块为收发转换开关。可选地，所述磁体模块包括单边磁体。本实施例的磁体模块采用单边磁体，无需额外的梯度***，从而降低了***的复杂度和硬件成本。
从而，本发明实施例的***，通过采集回波间隔不同的两个及以上的被测物质的磁共振脉冲序列的回波信号；采集完成后，通过控制台对回波信号分析处理得到带有横向弛豫及扩散衰减的信号，对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重；信号处理简单，不需采集大量数据，即可实现对物质含量的测量；从而本发明实施例的***具有采集时间短、降低储存需求数据处理耗时低以及拟合结果稳定、可重复性高等优点。
本领域普通技术人员可以理解：实现上述方法实施例的全部或部分步骤可以通过程序指令相关的硬件来完成，前述的程序可以存储于一计算机可读取存储介质中，该程序在执行时，执行包括上述方法实施例的步骤，而前述的存储介质包括：ROM、RAM、磁碟或者光盘等各种可以存储程序代码的介质。
本领域普通技术人员应明白，本发明的实施例可提供为方法、***、或计算机程序产品。因此，本发明可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本发明可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。
本发明是参照根据本发明实施例的方法、设备(***)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的 结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。
尽管已描述了本发明的优选实施例，但本领域内的技术人员一旦得知了基本创造性概念，则可对这些实施例做出另外的变更和修改。所以，所附权利要求意欲解释为包括优选实施例以及落入本发明范围的所有变更和修改。
显然，本领域的技术人员可以对本发明实施例进行各种改动和变型而不脱离本发明实施例的精神和范围。这样，倘若本发明实施例的这些修改和变型属于本发明权利要求及其等同技术的范围之内，则本发明也意图包含这些改动和变型在内。

Claims (10)

  1. 基于核磁共振***的物质测量方法，其特征在于，包括：向被测物质采集几组具有不同回波间隔的核磁共振脉冲序列回波信号并处理得到几组带有横向弛豫及扩散衰减的信号；结合先验知识对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重。
  2. 根据权利要求1所述的基于核磁共振***的物质测量方法，其特征在于：所述核磁共振脉冲序列为CPMG序列。
  3. 根据权利要求1或2所述的基于核磁共振***的物质测量方法，其特征在于：所述核磁共振***的梯度***包括单边磁体，所述单边磁体形成的天然梯度磁场能够对信号做扩散效应编码；所述回波间隔与b值满足如下关系式：
    Figure PCTCN2020130163-appb-100001
    式(4)中，G 0为磁场梯度；γ为旋磁比；b为b值；t E为回波间隔。
  4. 根据权利要求3所述的基于核磁共振***的物质测量方法，其特征在于：所述向被测物质采集几组具有不同回波间隔的核磁共振脉冲序列回波信号并处理得到几组带有横向弛豫及扩散衰减的信号，包括：将采集到的每组核磁共振脉冲序列回波信号表示为四维数组s(b,m,x,p),其中，第一维b为对应b值下的回波间隔的核磁共振脉冲序列回波信号，第二维m为回波链长度，第三维x为平均次数，第四维p为单次读出数据的采样点数；其中，m,x和p均为大于零的正整数；
    对所有的四维数组s(b,m,x,p)的第四维p做傅里叶变换后取低频部分作为平均值，对第三维x取平均后，得到几组带有横向弛豫及扩散衰减的信号。
  5. 根据权利要求4所述的基于核磁共振***的物质测量方法，其特征在于：所述结合先验知识对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重，包括：
    使用式(5)对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质 中成分的扩散系数、横向弛豫时间或/和含量权重：
    Figure PCTCN2020130163-appb-100002
    约束条件，
    Figure PCTCN2020130163-appb-100003
    其中，n为大于或等于零的正整数，a 3n+1为所含物质的权重，a 3n+2为物质的T2弛豫时间常数倒数，a 3n+3为物质扩散系数，k为噪声，s为核磁共振脉冲序列回波信号，‖  ‖表示二范数；约束条件中参数角标LB、UB分别为由先验知识取得的下限和上限。
  6. 一种实现权利要求1-5任意一项所述测量方法的***，其特征在于：包括
    控制台，用于发送发射核磁共振脉冲序列指令，接收核磁共振脉冲序列的回波信号，对所述回波信号分析处理得到带有横向弛豫及扩散衰减的信号，对所述带有横向弛豫及扩散衰减的信号进行拟合得到被测物质中成分的扩散系数、横向弛豫时间或/和含量权重；
    磁体模块，用于对被测物质产生梯度磁场；以及
    核磁共振***，用于接收发射核磁共振脉冲序列指令，并根据所述发射核磁共振脉冲序列指令发射用于施加于被测物质的核磁共振脉冲序列；用于接收被测物质的核磁共振脉冲序列的回波信号并向所述控制台反馈所述核磁共振脉冲序列的回波信号。
  7. 根据权利要求6所述的***，其特征在于：所述核磁共振***包括：
    核磁共振谱仪，用于接收发射核磁共振脉冲序列指令，并根据所述发射核磁共振脉冲序列指令发射核磁共振脉冲序列；用于接收射频***反馈的核磁共振脉冲序列的回波信号并向所述控制台反馈所述核磁共振脉冲序列的回波信号；以及
    射频***，用于对核磁共振脉冲序列处理以便于施加于被测物质，用于对所述核磁共振脉冲序列的回波信号处理以便于向控制台反馈，用于切换发射核磁共振脉冲序列模式和接收核磁共振脉冲序列的回波信号模式；用于发射核磁共振脉冲序列或接收核磁共振脉冲序列的回波信号。
  8. 根据权利要求7所述的***，其特征在于：所述射频***包括：
    收发转换模块，与核磁共振谱仪通讯，用于切换发射核磁共振脉冲序列模式和接收核磁共振脉冲序列的回波信号模式；以及
    射频线圈，与收发转换模块通讯，当收发转换模块切换为发射核磁共振脉冲序列模式时，所述射频线圈用于对被测物质产生激发中心频率；当收发转换模块切换为接收核磁共振脉冲序列的回波信号模式时，所述射频线圈用于接收核磁共振脉冲序列的回波信号。
  9. 根据权利要求8所述的***，其特征在于：所述收发转换模块为收发转换开关。
  10. 根据权利要求9所述的***，其特征在于：所述磁体模块包括单边磁体。
PCT/CN2020/130163 2020-06-29 2020-11-19 基于核磁共振***的物质测量方法及*** WO2022000948A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US18/068,133 US11766189B2 (en) 2020-06-29 2022-12-19 Nuclear magnetic resonance system-based substance measurement method and system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202010611176.6 2020-06-29
CN202010611176.6A CN111721795B (zh) 2020-06-29 2020-06-29 一种基于核磁共振***的物质测量方法及***

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/068,133 Continuation US11766189B2 (en) 2020-06-29 2022-12-19 Nuclear magnetic resonance system-based substance measurement method and system

Publications (1)

Publication Number Publication Date
WO2022000948A1 true WO2022000948A1 (zh) 2022-01-06

Family

ID=72571931

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/130163 WO2022000948A1 (zh) 2020-06-29 2020-11-19 基于核磁共振***的物质测量方法及***

Country Status (3)

Country Link
US (1) US11766189B2 (zh)
CN (1) CN111721795B (zh)
WO (1) WO2022000948A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117347416A (zh) * 2023-10-12 2024-01-05 无锡鸣石峻致医疗科技有限公司 一种物质成分的非侵入式检测方法、装置及存储介质
WO2024077688A1 (zh) * 2022-10-09 2024-04-18 无锡鸣石峻致医疗科技有限公司 一种磁共振***及其测量体表脂肪含量的方法

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111721795B (zh) 2020-06-29 2021-05-11 无锡鸣石峻致医疗科技有限公司 一种基于核磁共振***的物质测量方法及***
CN112415454B (zh) * 2020-11-09 2021-08-03 无锡鸣石峻致医疗科技有限公司 一种adc-t2二维图谱的测量方法、装置、计算机设备及非均匀场磁共振***
CN114186584B (zh) * 2021-12-06 2022-08-30 无锡鸣石峻致医疗科技有限公司 一种基于扩展指数模型对磁共振信号降噪的方法和设备
CN114167333B (zh) * 2021-12-06 2022-07-22 无锡鸣石峻致医疗科技有限公司 一种纵向弛豫时间测定方法、装置、计算机设备及存储介质
CN117310581B (zh) * 2023-10-11 2024-05-10 安徽峻德医疗科技有限公司 一种核磁共振信号衰减拟合方法、***、设备及存储介质

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7622919B2 (en) * 2006-07-31 2009-11-24 Schlumberger Technology Corporation Nuclear magnetic resonance measurement techniques in non-uniform fields
CN102116856A (zh) * 2010-12-30 2011-07-06 中国科学院深圳先进技术研究院 横向弛豫时间测量方法及***
CN105334239A (zh) * 2015-11-11 2016-02-17 中国石油大学(北京) 多维核磁共振流体组分含量测量方法及装置
CN108291440A (zh) * 2015-11-11 2018-07-17 斯伦贝谢技术有限公司 估算核磁共振测量质量
CN108520088A (zh) * 2018-02-27 2018-09-11 华东师范大学 基于数值模拟技术的仿真核磁共振弛豫谱分析方法及分析***
CN110916663A (zh) * 2019-12-05 2020-03-27 无锡鸣石峻致医疗科技有限公司 一种便携式核磁共振器官弹性无创定量检测方法
CN111721795A (zh) * 2020-06-29 2020-09-29 无锡鸣石峻致医疗科技有限公司 一种基于核磁共振***的物质测量方法及***

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6867589B2 (en) * 2002-08-09 2005-03-15 Schlumberger Technology Corporation Method for detecting hydrocarbons from NMR data
CN106772645B (zh) * 2016-12-15 2018-10-12 中国石油大学(北京) 基于一般先验信息约束的核磁共振数据反演方法和装置
CN106814337B (zh) * 2017-01-21 2019-04-30 厦门大学 一种无j偶合效应干扰的核磁共振横向弛豫测量方法
DE112018002703T5 (de) * 2017-05-24 2021-10-07 Schlumberger Technology B.V. Schnelle Messung und Interpretation von mehrdimensionalen Messungen im Bohrloch
CN111351813B (zh) * 2020-03-17 2021-09-24 无锡鸣石峻致医疗科技有限公司 一种基于非均匀场磁共振***的表观扩散系数测量方法
CN112462311B (zh) * 2020-11-09 2021-06-15 无锡鸣石峻致医疗科技有限公司 一种横向磁化矢量衰减时间常数的校正测量方法、装置、计算机设备及非均匀场磁共振***

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7622919B2 (en) * 2006-07-31 2009-11-24 Schlumberger Technology Corporation Nuclear magnetic resonance measurement techniques in non-uniform fields
CN102116856A (zh) * 2010-12-30 2011-07-06 中国科学院深圳先进技术研究院 横向弛豫时间测量方法及***
CN105334239A (zh) * 2015-11-11 2016-02-17 中国石油大学(北京) 多维核磁共振流体组分含量测量方法及装置
CN108291440A (zh) * 2015-11-11 2018-07-17 斯伦贝谢技术有限公司 估算核磁共振测量质量
CN108520088A (zh) * 2018-02-27 2018-09-11 华东师范大学 基于数值模拟技术的仿真核磁共振弛豫谱分析方法及分析***
CN110916663A (zh) * 2019-12-05 2020-03-27 无锡鸣石峻致医疗科技有限公司 一种便携式核磁共振器官弹性无创定量检测方法
CN111721795A (zh) * 2020-06-29 2020-09-29 无锡鸣石峻致医疗科技有限公司 一种基于核磁共振***的物质测量方法及***

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WANG HONGZHI, LIU XIANG;MIAO ZHI-YING;CHEN SHAN-SHAN;SHI QUN-YAN;XU LUO-YUAN;LU ZHI-YONG;LIU LI-RONG;YANG PEI-QIANG: "Design and Construction of a Fully-Opened Unilateral Nuclear Magnetic Resonance System", BOPUXUE ZAZHI = CHINESE JOURNAL OF MAGNETIC RESONANCE, ZHONGGUO KEXUEYUAN WUHAN WULI YANJIUSUO, WUHAN,, CN, vol. 31, no. 4, 31 December 2014 (2014-12-31), CN , pages 488 - 503, XP055885023, ISSN: 1000-4556 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024077688A1 (zh) * 2022-10-09 2024-04-18 无锡鸣石峻致医疗科技有限公司 一种磁共振***及其测量体表脂肪含量的方法
CN117347416A (zh) * 2023-10-12 2024-01-05 无锡鸣石峻致医疗科技有限公司 一种物质成分的非侵入式检测方法、装置及存储介质
CN117347416B (zh) * 2023-10-12 2024-05-31 无锡鸣石峻致医疗科技有限公司 一种物质成分的非侵入式检测方法、装置及存储介质

Also Published As

Publication number Publication date
US20230157567A1 (en) 2023-05-25
US11766189B2 (en) 2023-09-26
CN111721795B (zh) 2021-05-11
CN111721795A (zh) 2020-09-29

Similar Documents

Publication Publication Date Title
WO2022000948A1 (zh) 基于核磁共振***的物质测量方法及***
CN109270108B (zh) 多维核磁共振测量方法
US9588205B2 (en) Simultaneous and dynamic determination of longitudinal and transversal relaxation times of a nuclear spin system
US7863895B2 (en) System, program product, and method of acquiring and processing MRI data for simultaneous determination of water, fat, and transverse relaxation time constants
CN111537928B (zh) 一种基于扩散效应的磁共振***梯度场测量方法
CN112462311B (zh) 一种横向磁化矢量衰减时间常数的校正测量方法、装置、计算机设备及非均匀场磁共振***
US20110204892A1 (en) Spin echo spi methods for quantitative analysis of fluids in porous media
JP2015512317A (ja) Ａｐｔコントラスト向上および複数エコー時間におけるサンプリングを用いたｍｒ撮像
Elkins et al. Three-dimensional magnetic resonance velocimetry measurements of turbulence quantities in complex flow
CN111351813B (zh) 一种基于非均匀场磁共振***的表观扩散系数测量方法
US9389193B1 (en) Spatially resolved magnetic resonance spin-spin relaxation distribution measurement methods
CN112415454B (zh) 一种adc-t2二维图谱的测量方法、装置、计算机设备及非均匀场磁共振***
JPWO2015190508A1 (ja) 磁気共鳴イメージング装置及び水脂肪分離画像作成方法
JP2015525604A (ja) 改善された磁気共鳴収集のための方法およびシステム
US6291996B1 (en) Apparatus for and method of determining values of relaxation parameters
JP2019534086A (ja) サンプルに拡散強調磁気共鳴測定を実行する方法
CN111638479B (zh) 一种一维定位像获取方法及磁共振***
US4631480A (en) Nuclear magnetic resonance method and apparatus
US9864033B1 (en) Free induction decay based magnetic resonance imaging methods
JP5508165B2 (ja) 磁気共鳴イメージング装置及びｔ２マップ取得方法
JP3993173B2 (ja) Ｎｍｒ検査の間の励起方法
WO2024077688A1 (zh) 一种磁共振***及其测量体表脂肪含量的方法
JPH0573414B2 (zh)
JPH0670911A (ja) 磁気共鳴映像装置
JP2002204789A (ja) Ｍｒｉ装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20943394

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20943394

Country of ref document: EP

Kind code of ref document: A1