WO2021243975A1 - 剪切波衰减系数测量方法与系统 - Google Patents

剪切波衰减系数测量方法与系统 Download PDF

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WO2021243975A1
WO2021243975A1 PCT/CN2020/130245 CN2020130245W WO2021243975A1 WO 2021243975 A1 WO2021243975 A1 WO 2021243975A1 CN 2020130245 W CN2020130245 W CN 2020130245W WO 2021243975 A1 WO2021243975 A1 WO 2021243975A1
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magnetic resonance
radio frequency
attenuation coefficient
shear wave
measured object
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PCT/CN2020/130245
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French (fr)
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吴子岳
罗海
王伟谦
陈潇
叶洋
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无锡鸣石峻致医疗科技有限公司
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H11/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by detecting changes in electric or magnetic properties
    • G01H11/02—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by detecting changes in electric or magnetic properties by magnetic means, e.g. reluctance

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  • the embodiment of the present invention relates to a method and system for measuring shear wave attenuation coefficient.
  • Attenuation coefficient is also called attenuation constant. Is the real part of the propagation coefficient. It includes two parts: classical absorption and molecular absorption. Classical absorption is due to the viscosity of air, the effect of heat conduction, and the rotation of air molecules. Its magnitude is proportional to the square of the sound wave frequency and is related to air temperature and air pressure. This absorption generally does not need to be considered. . Molecular absorption is mainly caused by the vibrational relaxation effect of oxygen and nitrogen molecules in the air. It is closely related to the temperature and humidity of the air, and also changes with the increase or decrease of the sound wave frequency, but the law of change is more complicated.
  • the attenuation coefficient describes the attenuation rate of the wave propagating in the material, and is an important indicator reflecting the absorption performance of the material.
  • the attenuation coefficient can reflect the changes in tissue elasticity, fat content, and water content, which are closely related to the physiological and pathological conditions.
  • the calculation of the attenuation coefficient often requires the use of shear wave amplitude data.
  • the attenuation of shear wave in the medium can be described by the following formula
  • a 0 is the initial amplitude of the shear wave
  • r is the distance between the location of the measured object and the vibration source
  • ⁇ is the attenuation coefficient
  • a 1 and A 2 are the amplitudes of two points at different distances from the vibration source within the measured object, ⁇ r is the distance between the two points, and ⁇ is the attenuation coefficient.
  • the amplitude data of the shear wave needs to be measured. According to the method of collecting shear wave amplitude, standing wave method and ultrasonic detection method are common.
  • the standing wave method is the most direct measurement method and is suitable for a variety of mechanical waves.
  • the attenuation coefficient of A and A 0 are the amplitudes of r and the vibration source respectively.
  • the output voltage (U) and the received voltage (U 0 ) are proportional to the amplitude. Available
  • the above method requires the intercepted substance to be contained in the measuring equipment container, or the generator/receiver is deep into the medium to measure the amplitude of the propagated signal, which is suitable for gas and liquid.
  • Ultrasonic detection method is a measurement method based on ultrasound imaging; it is suitable for measuring the attenuation coefficient of solids, that is, applying an external excitation vibration to generate a shear wave with a frequency of ⁇ in the tissue, and select two distances in the wave propagation direction
  • the points of ⁇ r are respectively r 1 -r 2 away from the excitation vibration source.
  • use the ultrasonic probe to excite and collect the two vibration curves of the particle with time at the same set frame rate, and then use the Kalman filter to extract the signal of the vibration frequency ⁇ from the two vibration curves, and the extracted signal
  • the amplitude is the amplitude of the corresponding position.
  • the standing wave method is suitable for liquids and gases. When measuring, it is necessary to immerse the detector in the substance or intercept the substance sample.
  • the scope of application is narrow; the ultrasonic detection attenuation coefficient has the advantages of low cost and rapid quantification, but the ultrasonic penetration is easily affected by the medium , hardly lead to measurement failure.
  • the embodiment of the present invention provides a method and system for measuring shear wave attenuation coefficient, which solves the problem that the ultrasonic detection method cannot penetrate certain media and causes measurement failure.
  • the shear wave attenuation coefficient measurement method includes: applying a nuclear magnetic resonance pulse sequence to a measured object with a stable vibration state, and performing motion encoding with a static or controllable gradient magnetic field to detect at least two of the measured objects The nuclear magnetic resonance echo signals at different positions are analyzed and processed to obtain the shear wave attenuation coefficient.
  • the nuclear magnetic resonance pulse sequence is applied to the measured object in a stable vibration state, and a static or controllable gradient magnetic field is used for motion coding to detect the measured object NMR echo signals at at least two different positions, including: applying a 90° radio frequency pulse to the measured object in a simplistic resonance motion and in a gradient magnetic field, and determining the application time of at least one 180° radio frequency pulse according to the frequency of the vibration source At this moment, the at least one 180° radio frequency pulse is applied to the measured object in a stable vibration state.
  • the measuring the nuclear magnetic resonance echo signals of at least two different positions of the measured object includes detecting the measured object NMR echo signals of different center frequencies;
  • the NMR echo signals includes detecting the NMR echo signals at different positions of the magnet and/or the probe and the measured object.
  • the measuring the NMR echo signals of at least two different positions of the measured object includes equal intervals for each position Adjust the initial phase of the vibration source to obtain a series of NMR echo signals at that location.
  • the adjusting the initial phase of the vibration source at equal intervals for each position includes adjusting the vibration source at equal intervals.
  • the initial phase of the vibration source, the interval is greater than 2 ⁇ .
  • the analyzing and processing the nuclear magnetic resonance echo signal to obtain the shear wave attenuation coefficient includes:
  • S1( ⁇ ,n) is the NMR echo signal collected at the first position
  • S2( ⁇ ,n) is the NMR echo signal collected at the second position
  • ⁇ represents the initial phase of the vibration source
  • the first Two-dimensional n represents the number of echo points
  • G is the motion sensitive gradient
  • ⁇ is the Larmor frequency
  • T is the shear wave vibration period
  • N is the number of shear wave cycles in the entire motion encoding duration
  • ⁇ is the attenuation coefficient
  • r 1 is the distance from the first position to the vibration source
  • r 2 is the distance from the second position to the vibration source.
  • a measurement system for realizing the shear wave attenuation coefficient measurement method including
  • Magnetic resonance system used to transmit radio frequency pulses according to nuclear magnetic resonance pulse sequence instructions, locate the spatial position of the measured object, and receive nuclear magnetic resonance echo signals;
  • the mechanical vibration excitation device is used for receiving the radio frequency pulse signal sent by the magnetic resonance system and causing the measured object to generate simple resonance according to the signal;
  • the nuclear magnetic resonance console controls the magnetic resonance system to run nuclear magnetic resonance pulse sequence instructions, receives the nuclear magnetic resonance echo signals collected by the magnetic resonance system, and analyzes and processes the nuclear magnetic resonance echo signals.
  • the magnetic resonance system includes a magnetic resonance spectrometer, a radio frequency power amplifier, a preamplifier, a transceiver switching module, a magnet module, and a radio frequency probe;
  • the magnetic resonance spectrometer is used to send a trigger signal to the mechanical vibration excitation device, and the magnetic resonance spectrometer is connected to the transceiver switching module through a radio frequency power amplifier;
  • a transceiver switching module for switching the transmitting state and receiving state of the magnetic resonance system
  • Radio frequency probe the radio frequency probe is connected to the transceiver switching module; in the transmitting state, the radio frequency probe is used to transmit radio frequency pulses to the measured object; in the receiving state, the radio frequency probe is used to receive the measured object and detect that the target position is excited NMR echo signal generated later;
  • the magnet module is used to generate a static gradient magnetic field for spatial positioning of the measured object.
  • the mechanical vibration excitation device includes a signal generator, a power amplifier, and a vibration generator;
  • a signal generator for receiving a trigger signal from a magnetic resonance spectrometer and driving the vibration generator to generate simple harmonic motion according to the trigger signal
  • the vibration generator is connected with a transmission rod; the vibration generator acts on the measured object through the transmission rod to cause the measured object to generate simple harmonic motion.
  • the transceiver switching module is connected to the magnetic resonance spectrometer through a preamplifier; the vibration generator is connected to the signal generator through a power amplifier .
  • the shear wave attenuation coefficient measurement method and system of the embodiment of the present invention measure the attenuation coefficient of a solid or semi-solid in a non-invasive and non-destructive manner based on the principle of magnetic resonance; obviously, it avoids that the ultrasonic detection method cannot penetrate some The medium causes the problem of measurement failure.
  • Figure 1 is a schematic diagram of the principle of measuring attenuation coefficient by standing wave method.
  • Fig. 2 is a schematic flowchart of a measurement method according to an embodiment of the present invention.
  • Fig. 3 is a schematic diagram of the system structure of an embodiment of the present invention.
  • Fig. 4 is a schematic structural diagram of an added gradient system according to an embodiment of the present invention.
  • Fig. 5 is a schematic diagram of a magnetic field distribution of a magnet module according to an embodiment of the present invention.
  • Fig. 6 is a schematic diagram of a nuclear magnetic resonance pulse sequence according to an embodiment of the present invention.
  • the embodiments of the present invention provide a shear wave attenuation coefficient measurement method and system, which are used to solve the problem that the ultrasonic detection method in the prior art cannot penetrate certain media and cause measurement failure.
  • the method and the system are based on the same inventive concept. Since the principles of the method and the device to solve the problem are similar, the implementation of the device and the method can be referred to each other, and the repetition will not be repeated.
  • the embodiment of the present invention provides a shear wave attenuation coefficient measurement method and system.
  • the method and system are based on the principle of low-field nuclear magnetic resonance to measure the attenuation coefficient of a solid or semi-solid in a non-invasive and non-destructive manner.
  • the measurement method of the embodiment of the present invention also has the advantages of low cost, short measurement time, accurate positioning, and high repeatability of measurement results. It can be used for industrial testing as well as medical testing.
  • the preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.
  • an embodiment of the present invention provides a shear wave attenuation coefficient measurement method, which includes: applying a nuclear magnetic resonance pulse sequence to a measured object in a stable vibration state, and performing motion encoding in conjunction with a static or controllable gradient magnetic field to detect the The nuclear magnetic resonance echo signals of at least two different positions of the measured object are analyzed and processed to obtain a shear wave attenuation coefficient.
  • the motion coding of the measured object is performed, the spatial position of the measured object is located, and the magnetic resonance signals of at least two different positions are collected. Finally, the phase information of the magnetic resonance signal and the measured point Information such as the distance from the vibration source directly calculates the attenuation coefficient.
  • the application of a nuclear magnetic resonance pulse sequence to the measured object in a stable vibration state, and a motion encoding with a static or controllable gradient magnetic field, to detect the nuclear magnetic resonance echo signals of at least two different positions of the measured object Including: applying a 90° radio frequency pulse to a measured object in a gradient magnetic field that is in a simple harmonic vibration, determining the application time of at least one 180° radio frequency pulse according to the frequency of the vibration source, and stabilizing the vibration state at this time
  • the measured object applies the at least one 180° radio frequency pulse.
  • a 90° RF pulse is applied. Due to the magnetic field gradient, spins within a certain thickness within the ROI will be excited.
  • the application of the 180° pulse can be determined according to the frequency of the vibration source. time. After the 180° pulse, the spins converge, and the echo signals are detected at two different points in the substance and sent back to the console to complete the calculation.
  • partial motion coding can be used to shorten the echo time or multiple signal accumulations to improve the signal-to-noise ratio.
  • multiple 180° pulses can be applied.
  • the gradient magnetic field is mainly used for spatial positioning, including phase encoding and frequency encoding, and can be used to determine any position in space through the gradient magnetic field.
  • the system of the embodiment of the present invention adopts a unilateral magnet with a special magnetic field distribution. Generally, a traditional low-field magnetic resonance system or other forms of magnet design can also achieve the same purpose.
  • measuring the nuclear magnetic resonance echo signals of at least two different positions of the measured object includes detecting the nuclear magnetic resonance echo signals of different center frequencies of the measured object; or including detecting the magnet and/or the probe and the NMR echo signals at different positions of the measured object.
  • the embodiment of the present invention needs to measure the magnetic resonance signals at two positions, which can be achieved by changing the center frequency or changing the relative positions of the magnet, the probe, and the object to be measured.
  • the measuring the nuclear magnetic resonance echo signals of at least two different positions of the measured object includes adjusting the initial phase of the vibration source at equal intervals for each position to obtain a series of nuclear magnetic resonance echoes at that position Signal.
  • a set of NMR echo signals are collected for each position; the collection of a set of NMR echo signals for each position can be obtained by adjusting the initial phase of the vibration source at equal intervals for each position, so
  • the equal interval means that the difference between the initial phases in each vibration state is fixed; preferably, the value of the equal interval of each initial phase is greater than 2 ⁇ .
  • the analyzing and processing the nuclear magnetic resonance echo signal to obtain a shear wave attenuation coefficient includes:
  • S1( ⁇ ,n) is the NMR echo signal collected at the first position
  • S2( ⁇ ,n) is the NMR echo signal collected at the second position
  • ⁇ represents the initial phase of the vibration source
  • the first Two-dimensional n represents the number of echo points
  • G is the motion sensitive gradient
  • ⁇ is the Larmor frequency
  • T is the shear wave vibration period
  • N is the number of shear wave cycles in the entire motion encoding duration
  • ⁇ is the attenuation coefficient
  • r 1 is the distance from the first position to the vibration source
  • r 2 is the distance from the second position to the vibration source.
  • the first position and the second position correspond to the two measured positions one-to-one; when the measured positions are 3 or more, the first position and the second position are 3 and Any two of the above measurement positions.
  • the embodiment of the present invention only describes the method for calculating the attenuation coefficient by collecting two positions. In fact, it is possible to collect more than two positions and measure the attenuation coefficient by a method similar to the method disclosed in the present invention, which should all fall within the protection scope of the present invention.
  • a person of ordinary skill in the art can understand that all or part of the steps in the above method embodiments can be implemented by a program instructing relevant hardware.
  • the foregoing program can be stored in a computer readable storage medium. When the program is executed, the program is executed.
  • the steps of the foregoing method embodiment are included, and the foregoing storage medium includes: ROM, RAM, magnetic disk, or optical disk, and other media that can store program codes.
  • the embodiment of the present invention also provides a measurement system for realizing the shear wave attenuation coefficient measurement method, including a magnetic resonance system, which is used to transmit radio frequency pulses according to the instructions of the nuclear magnetic resonance pulse sequence to locate the Measure the spatial position of the object, used to receive nuclear magnetic resonance echo signals; mechanical vibration excitation device, used to receive the radio frequency pulse signal sent by the magnetic resonance system and make the measured object generate simple resonance according to the signal; nuclear magnetic resonance console , Controlling the magnetic resonance system to run the nuclear magnetic resonance pulse sequence command, receiving the nuclear magnetic resonance echo signal collected by the magnetic resonance system, and analyzing and processing the nuclear magnetic resonance echo signal.
  • a magnetic resonance system which is used to transmit radio frequency pulses according to the instructions of the nuclear magnetic resonance pulse sequence to locate the Measure the spatial position of the object, used to receive nuclear magnetic resonance echo signals
  • mechanical vibration excitation device used to receive the radio frequency pulse signal sent by the magnetic resonance system and make the measured object generate simple resonance according to the signal
  • nuclear magnetic resonance console Controlling the magnetic resonance system to run the nuclear magnetic resonance pulse sequence
  • both the magnetic resonance spectrometer and the magnet module are portable in order to facilitate carrying.
  • the magnetic resonance system is a portable low-field magnetic resonance system, so that the overall system is lighter, more convenient, and less costly.
  • the nuclear magnetic resonance console sends the nuclear magnetic resonance pulse sequence command to the mechanical vibration excitation device.
  • the mechanical vibration excitation device acts on the measured object to generate simple resonance.
  • the measured object is positioned in the magnetic resonance system through a gradient magnetic field.
  • Magnetic resonance The system receives the NMR echo signal of the measured object and returns it to the NMR console; the NMR console controls the mechanical vibration excitation device to adjust the initial phase of the vibration source at equal intervals at each position to obtain a series of NMR.
  • the echo signal returns to the nuclear magnetic resonance console; the nuclear magnetic resonance console can also generate nuclear magnetic resonance at different positions by changing the center frequency or changing the relative position of the magnet, the probe and the measured object through instructions and corresponding actuators.
  • the nuclear magnetic resonance console receives a series of nuclear magnetic resonance echo signals from different positions and analyzes and processes the nuclear magnetic resonance echo signals to obtain the attenuation coefficient.
  • the magnetic resonance system includes a magnetic resonance spectrometer, a radio frequency power amplifier, a preamplifier, a transceiver switching module, a magnet module, and a radio frequency probe; the magnetic resonance spectrometer is used to send a trigger signal to the mechanical vibration excitation device.
  • the magnetic resonance spectrometer is connected to the transceiver switch module through the radio frequency power amplifier; the transceiver switch module is used to switch the transmission state and the reception state of the magnetic resonance system; the radio frequency probe, the radio frequency probe is connected to the transceiver switch module; The radio frequency probe is used to transmit radio frequency pulses to the measured object; in the receiving state, the radio frequency probe is used to receive the nuclear magnetic resonance echo signal generated after the detection target position of the measured object is excited; the magnet module is used to generate a static gradient magnetic field Position the measured object in space.
  • the transceiver switching module is connected to the magnetic resonance spectrometer through a preamplifier; the vibration generator is connected to the signal generator through a power amplifier.
  • the magnetic resonance spectrometer is connected to the transceiver switch through the radio frequency power amplifier; the magnetic resonance spectrometer is connected to the transceiver switch through the preamplifier; the magnetic resonance spectrometer is connected to the radio frequency probe through the transceiver switch;
  • the transceiver switching module is used to switch the portable magnetic resonance system in the transmitting state or the receiving state. In the transmitting state, the probe emits radio frequency pulses; in the receiving state, the radio frequency probe is used to receive the object to be measured after the target position is excited. The resulting NMR echo signal.
  • the magnetic resonance spectrometer communicates with the mechanical vibration excitation device; the magnetic resonance console is connected to the magnetic resonance spectrometer and the transceiver switch through the radio frequency power amplifier; the magnet module is set on the back side of the radio frequency probe; the object to be measured is set on the radio frequency probe and the machine Between the transmission rods of the vibration excitation device; the transmission rod transmits the vibration of the mechanical vibration excitation device to the measured object, so that the measured object performs simple harmonic vibration in the gradient magnetic field of the magnet module.
  • the magnetic resonance spectrometer does not have a gradient control module, so there is no need to provide a corresponding gradient coil.
  • the magnet module is equipped with a unilateral magnet, and the back is connected with a yoke. The back magnetic field strength decays rapidly.
  • the unilateral magnet generates a static magnetic field.
  • the static magnetic field is linear or approximately linear in the AP-LR plane within the ROI range. Gradient, outside the ROI range, the magnetic field decays uniformly and rapidly; the magnetic field distribution of the magnet module is shown in Figure 6.
  • the magnetic resonance system further includes a gradient system; the gradient system includes a gradient amplifier and a gradient coil; the gradient amplifier communicates with the magnetic resonance spectrometer, and the gradient The amplifier is connected with the gradient coil; the gradient coil is arranged between the radio frequency probe and the magnet module, and is used to generate a controllable gradient magnetic field for the measured object.
  • the gradient system is composed of a gradient amplifier and a gradient coil, which is controlled by a magnetic resonance spectrometer. After the signal is amplified by the gradient amplifier, the gradient coil forms a gradient magnetic field in the space where the measured object is located; in this embodiment, the pulse sequence and the static gradient magnetic field are combined In addition to motion encoding, the pulse sequence can also be coordinated with the gradient system to use the controllable gradient magnetic field generated by the gradient coil to perform motion encoding.
  • the magnetic resonance spectrometer is provided with a transmission and gating unidirectional signal path, and the magnetic resonance spectrometer is connected to a radio frequency power amplifier through a transmission and gating unidirectional signal path; the magnetic resonance spectrometer is connected to a radio frequency power amplifier through a transceiver conversion gate
  • the control is connected with the transceiver switch, the radio frequency power amplifier amplifies the transmitted signal and is connected with the transceiver switch, and the transceiver switch is connected with the radio frequency probe.
  • the mechanical vibration excitation device includes a signal generator, a power amplifier, and a vibration generator; the signal generator is used to receive a trigger signal from a magnetic resonance spectrometer and drive the vibration generator to generate simple harmonic vibration according to the trigger signal;
  • the vibration generator is connected with a transmission rod; the vibration generator acts on the measured object through the transmission rod to cause the measured object to generate simple harmonic motion.
  • the signal generator is a waveform generator, the waveform generator sends a 50HZ sine wave to the power amplifier for amplification, the vibration power amplifier is connected to the signal generator, and the signal generator is connected to the magnetic resonance spectrometer to receive magnetic resonance.
  • the trigger signal from the spectrometer is transmitted by the signal generator to the vibration generator, and the vibration generator drives the transmission rod to generate a simple harmonic vibration; the simple resonator closely adheres to the adjacent surface of the measured substance via the transmission rod and vibrates after it vibrates.
  • Shear waves are generated inside, and the shear waves propagate in the AP direction, causing the particles in the tissue to make simple harmonic motions in the LR direction.
  • the NMR console is connected to the magnetic resonance spectrometer to control and run the magnetic resonance pulse Sequence instructions and receive the NMR echo signals collected by the magnetic resonance spectrometer to complete real-time data processing.
  • the embodiments of the present invention may be provided as a method, a system, or a computer program product. Therefore, the present invention may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.
  • computer-usable storage media including but not limited to disk storage, CD-ROM, optical storage, etc.
  • These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing equipment to work in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction device.
  • the device implements the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.
  • These computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operation steps are executed on the computer or other programmable equipment to produce computer-implemented processing, so as to execute on the computer or other programmable equipment.
  • the instructions provide steps for implementing functions specified in a flow or multiple flows in the flowchart and/or a block or multiple blocks in the block diagram.

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Abstract

一种剪切波衰减系数测量方法，包括：向振动状态稳定的被测物体施加核磁共振脉冲序列，并配合静态或可控梯度磁场进行运动编码，以检测被测物体至少两个不同位置的核磁共振回波信号，分析处理核磁共振回波信号得到剪切波衰减系数；系统包括磁共振系统、机械振动激励装置和核磁共振控制台；实施例基于低场核磁共振以非侵入式、非破坏式的方式测量固体或者半固体的衰减系数。解决了超声检测法不能穿透某些介质导致测量失败的问题。

Description

剪切波衰减系数测量方法与系统 技术领域
本发明实施例涉及剪切波衰减系数测量方法与系统。
背景技术
衰减系数又称衰减常数。是传播系数的实数部分。它包括两部分：经典吸收和分子吸收。经典吸收是由于空气的粘滞性、热传导效应以及空气分子转动等所产生的声能耗散，其大小与声波频率的平方成正比例，并且与空气温度和气压有关，这种吸收一般可以不考虑。分子吸收主要是空气中氧和氮分子振动弛豫效应所引起的，它与空气的温度和湿度密切相关，也随声波频率的增减而变化，但变化规律较为复杂。
衰减系数描述了波在物质中传播的衰减速率，是反映材料吸收性能的重要指标。在医学上，衰减系数可以反映组织的弹性、脂肪含量、含水量的变化等与生理病理状态密切相关的参数指标。
对于衰减系数的计算往往需要利用剪切波的振幅数据来进行。剪切波在介质中的衰减可以用如下公式描述
Figure PCTCN2020130245-appb-000001
其中，A 0为剪切波的初始振幅，r为被测物体所在位置与振源的距离，α为衰减系数。
现有衰减系数的测量技术大多基于该衰减模型进行改进。该测量技术需要在介质内两点采集振幅，再根据式(1)算出衰减系数：
Figure PCTCN2020130245-appb-000002
其中，A 1,A 2分别为波在被测物体内距振源不同距离两点的振幅，Δr为两点间距离，α为衰减系数。
剪切波的振幅数据需要经过测量得到。根据采集剪切波振幅的方式分类，常见的有驻波法和超声检测法。
驻波法为最直接的测量方法，适用于多种机械波。如图1所示，由发生器产生在固定长度介质内传播的驻波，其在介质内损耗大致遵循A＝A 0(1+R)e -αr，其中，R为反射系数,α是介质的衰减系数,A和A 0分别为距振源r处与振源处振幅。因为发生器和接收器为同一材料制成，输出电压(U)和接收电压(U 0)与振幅成正比。可得
Figure PCTCN2020130245-appb-000003
上述方法需将截取物质装盛在测量设备容器里，或将发生/接收器深入介质内测量传播信号振幅大小，其适用于气体和液体。
超声检测法是基于超声成像的测量方法；适用于固体内衰减系数的测量，即在施加一个外部激励振动，在组织内产生频率为ω的剪切波，并在波传播方向上选择两个相距Δr的点，分别距激励振源r 1-r 2。在选定两点用超声探头以同样的设定帧率激发采集到两条质点随时间振动曲线，后分别从两条振动曲线中利用卡尔曼滤波抽取出振动频率ω的信号，所抽取出信号幅度即为对应位置的振幅。
驻波法适用于液体和气体，测量时需要将探测器浸入物质内部或截取物质样本，适用范围较窄；超声检测衰减系数具有低成本、快速定量等优点，但超声波穿透性易受介质影响，容易导致测量失败。
发明内容
本发明实施例提供剪切波衰减系数测量方法与系统，解决了超声检测法不能穿透某些介质导致测量失败的问题。
第一方面，剪切波衰减系数测量方法，包括：向振动状态稳定的被测物体 施加核磁共振脉冲序列，并配合静态或可控梯度磁场进行运动编码，以检测所述被测物体至少两个不同位置的核磁共振回波信号，分析处理所述核磁共振回波信号得到剪切波衰减系数。
结合第一方面，在第一种可能的实现方式中，所述向振动状态稳定的被测物体施加核磁共振脉冲序列，并配合静态或可控梯度磁场进行运动编码，以检测所述被测物体至少两个不同位置的核磁共振回波信号，包括：向作简谐振动的、处于梯度磁场中的被测物体施加90°射频脉冲，根据振动源的频率确定至少一个180°射频脉冲的施加时刻并于该时刻向所述振动状态稳定的被测物体施加所述至少一个180°射频脉冲。
结合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，所述测量所述被测物体至少两个不同位置的核磁共振回波信号，包括检测所述被测物体不同中心频率的核磁共振回波信号；
或包括检测磁体和/或探头与所述被测物体的不同位置处的核磁共振回波信号。
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，所述测量所述被测物体至少两个不同位置的核磁共振回波信号，包括对每一个位置等间隔的调整振动源的初始相位用以获取该位置一系列的核磁共振回波信号。
结合第一方面或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，所述对每一个位置等间隔的调整振动源的初始相位，包括等间隔的调整所述振动源的初始相位，所述间隔大于2π。
结合第一方面或第一方面的上述任一种可能的实现方式，在第五种可能的实施方式中，所述分析处理所述核磁共振回波信号得到剪切波衰减系数，包括：
设S1(θ,n)为在第一位置采集到的核磁共振回波信号，S2(θ,n)为在第二位置采集到的核磁共振回波信号，θ表示振动源的初始相位，第二维n表示 回波的点数；
分别对S1(θ,n)和S2(θ,n)的第二维做一维傅里叶变换，取最低频部分的相位，分别得到
Figure PCTCN2020130245-appb-000004
和
Figure PCTCN2020130245-appb-000005
分别对
Figure PCTCN2020130245-appb-000006
和
Figure PCTCN2020130245-appb-000007
做一维相位反卷折运算；
分别计算
Figure PCTCN2020130245-appb-000008
和
Figure PCTCN2020130245-appb-000009
即分别计算
Figure PCTCN2020130245-appb-000010
和
Figure PCTCN2020130245-appb-000011
的峰值，得到
Figure PCTCN2020130245-appb-000012
Figure PCTCN2020130245-appb-000013
计算第一位置和第二位置处剪切波振幅
Figure PCTCN2020130245-appb-000014
Figure PCTCN2020130245-appb-000015
式(5)和(6)中，G为运动敏感梯度，γ为拉莫尔频率，T为剪切波振动周期，N为在整个运动编码持续时间内剪切波的周期数目；
按以下公式(7)运算出剪切波在组织内传播的衰减系数值
Figure PCTCN2020130245-appb-000016
式(7)中α是衰减系数，r 1是第一位置距振源距离，r 2是第二位置距振源距离。
第二方面，一种用于实现所述的剪切波衰减系数测量方法的测量系统，包括
磁共振系统，用于按照核磁共振脉冲序列指令发射射频脉冲，定位被测物体空间位置，用于接收核磁共振回波信号；
机械振动激励装置，用于接收所述磁共振系统发出的射频脉冲信号并根据所述信号使被测物体产生简谐振动；
核磁共振控制台，控制磁共振系统运行核磁共振脉冲序列指令，接收磁共振系统采集到的核磁共振回波信号，对所述核磁共振回波信号分析处理。
结合第二方面，在第一种可能的实现方式中，所述磁共振系统包括磁共振谱仪、射频功放、前置放大器、收发切换模块、磁体模块以及射频探头；
磁共振谱仪，用于向机械振动激励装置发送触发信号，所述磁共振谱仪通过射频功放与收发切换模块连接；
收发切换模块，用于切换所述磁共振系统的发射状态和接收状态；
射频探头，所述射频探头与收发切换模块连接；发射状态下，所述射频探头用于向被测物体发射射频脉冲；接收状态下，所述射频探头用于接收被测物体检测靶位受激发后产生的核磁共振回波信号；
磁体模块，用于产生静态梯度磁场对被测物体进行空间定位。
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，所述机械振动激励装置包括信号发生器、功率放大器和振动发生器；
信号发生器，用于接收磁共振谱仪发出的触发信号并根据所述触发信号驱动振动发生器产生简谐振动；
振动发生器，所述振动发生器与传动杆连接；所述振动发生器通过传动杆作用于被测物体使所述被测物体产生简谐振动。
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，收发切换模块通过前置放大器与磁共振谱仪连接；所述振动发生器通过功率放大器与信号发生器连接。
本发明实施例的剪切波衰减系数测量方法与系统，基于磁共振原理以非侵入式，非破坏式的方式测量固体或者半固体的衰减系数；显然，避免了超声检测法不能穿透某些介质导致测量失败的问题。
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是驻波法测量衰减系数的原理示意图。
图2是本发明实施例的测量方法流程示意图。
图3是本发明实施例的系统结构示意图。
图4是本发明实施例增加梯度系统的结构示意图。
图5是本发明实施例的磁体模块磁场分布示意图。
图6是本发明实施例的核磁共振脉冲序列示意图。
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。
本发明实施例提供剪切波衰减系数测量方法与系统，用以解决现有技术中超声检测法不能穿透某些介质导致测量失败的问题。其中，方法和系统是基于同一发明构思的，由于方法及装置解决问题的原理相似，因此装置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。
本发明实施例提供了剪切波衰减系数测量方法与系统，该方法与系统基于低场核磁共振原理实现，以非侵入式，非破坏式的方式测量固体或者半固体的衰减系数。本发明实施例的测量方法还具有低成本、测量时间短、定位准确、测量结果可重复性高的优点。具有既可以用于工业检测，也可以用于医学检测的特点。下面结合附图对本发明优选的实施方式进行详细说明。
参阅图2所示，本发明实施例提供剪切波衰减系数测量方法，包括：向振动状态稳定的被测物体施加核磁共振脉冲序列，并配合静态或可控梯度磁场进行运动编码，以检测所述被测物体至少两个不同位置的核磁共振回波信号，分析处理所述核磁共振回波信号得到剪切波衰减系数。
通过对被测物体施加核磁共振脉冲序列，对被测物体进行运动编码，定位被测物体的空间位置，采集至少两个不同位置的磁共振信号，最终由磁共振信号的相位信息和所测点与振动源的距离等信息直接计算出衰减系数。
可选地，所述向振动状态稳定的被测物体施加核磁共振脉冲序列，并配合静态或可控梯度磁场进行运动编码，以检测所述被测物体至少两个不同位置的核磁共振回波信号，包括：向作简谐振动的、处于梯度磁场中的被测物体施加90°射频脉冲，根据振动源的频率确定至少一个180°射频脉冲的施加时刻并于该时刻向所述振动状态稳定的被测物体施加所述至少一个180°射频脉冲。
如图5所示，在振动状态稳定后，施加一个90°射频脉冲，由于磁场梯度的存在，ROI范围内一定厚度内的自旋将被激发，根据振动源的频率可以确定180°脉冲的施加时刻。在180°脉冲之后，自旋聚相，在物质内不同两点检测回波信号并传回控制台完成计算。在实际中，可以通过部分运动编码缩短回波时间或多次信号累加来提高信噪比。此外，为了提高相位信噪比，可以施加多个180°脉冲。
定位被测物体的空间位置，可以使用梯度磁场作用与被测物体的方式来实 现。梯度磁场主要用于空间定位，包括相位编码及频率编码，可以通过梯度磁场明确空间上的任意位置。本发明实施例的系统采用了特殊磁场分布的单边磁体，一般地，采用传统的低场磁共振系统或其他形式的磁体设计方案也能达到相同的目的。
可选地，测量所述被测物体至少两个不同位置的核磁共振回波信号，包括检测所述被测物体不同中心频率的核磁共振回波信号；或包括检测磁体和/或探头与所述被测物体的不同位置处的核磁共振回波信号。
本发明实施例需要测量两个位置的磁共振信号，可以通过改变中心频率的方式或者改变磁体、探头与被测物体的相对位置的方式实现。
可选地，所述测量所述被测物体至少两个不同位置的核磁共振回波信号，包括对每一个位置等间隔的调整振动源的初始相位用以获取该位置一系列的核磁共振回波信号。
优选地，对每个位置采集一组核磁共振回波信号；对每个位置的一组核磁共振回波信号的采集，可以通过对每一个位置等间隔的调整振动源的初始相位来获得，所述等间隔指的是各个振动状态下各个初始相位的差值固定；优选地，各个初始相位的等间隔的值大于2π。
可选地，所述分析处理所述核磁共振回波信号得到剪切波衰减系数，包括：
设S1(θ,n)为在第一位置采集到的核磁共振回波信号，S2(θ,n)为在第二位置采集到的核磁共振回波信号，θ表示振动源的初始相位，第二维n表示回波的点数；
分别对S1(θ,n)和S2(θ,n)的第二维做一维傅里叶变换，取最低频部分的相位，分别得到
Figure PCTCN2020130245-appb-000017
和
Figure PCTCN2020130245-appb-000018
分别对
Figure PCTCN2020130245-appb-000019
和
Figure PCTCN2020130245-appb-000020
做一维相位反卷折运算；
分别计算
Figure PCTCN2020130245-appb-000021
和
Figure PCTCN2020130245-appb-000022
即分别计算
Figure PCTCN2020130245-appb-000023
和
Figure PCTCN2020130245-appb-000024
的峰值，得到
Figure PCTCN2020130245-appb-000025
Figure PCTCN2020130245-appb-000026
计算第一位置和第二位置处剪切波振幅
Figure PCTCN2020130245-appb-000027
Figure PCTCN2020130245-appb-000028
式(5)和(6)中，G为运动敏感梯度，γ为拉莫尔频率，T为剪切波振动周期，N为在整个运动编码持续时间内剪切波的周期数目；
按以下公式(7)运算出剪切波在组织内传播的衰减系数值
Figure PCTCN2020130245-appb-000029
式(7)中α是衰减系数，r 1是第一位置距振源距离，r 2是第二位置距振源距离。
其中，当测量的位置为两个时，第一位置和第二位置与测量的两个位置一一对应；当测量的位置为3个及以上时，第一位置和第二位置为3个及以上的测量位置中的任意两个。
本发明实施例仅阐述采集了两个位置进行衰减系数计算的方法。实际上，可以采集两个以上的位置，用与本发明公开方法类似的方法测量衰减系数，都应属于本发明的保护范围。
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。
如图3所示，本发明实施例还提供一种用于实现所述的剪切波衰减系数测量方法的测量系统，包括磁共振系统，用于按照核磁共振脉冲序列指令发射射频脉冲，定位被测物体空间位置，用于接收核磁共振回波信号；机械振动激励装置，用于接收所述磁共振系统发出的射频脉冲信号并根据所述信号使被测物体产生简谐振动；核磁共振控制台，控制磁共振系统运行核磁共振脉冲序列指令，接收磁共振系统采集到的核磁共振回波信号，对所述核磁共振回波信号分析处理。
可选地，为便于携带所述磁共振谱仪和磁体模块均为便携式。所述磁共振系统为便携式低场磁共振系统，从而，使整体系统更轻巧便捷，成本更低。
核磁共振控制台发送核磁共振脉冲序列指令至机械振动激励装置，机械振动激励装置作用于被测物体使其产生简谐振动，被测物体在磁共振系统中通过梯度磁场进行空间位置定位，磁共振系统将被测物体的核磁共振回波信号接收后返回至核磁共振控制台；核磁共振控制台通过指令控制机械振动激励装置对每一个位置等间隔的调整振动源的初始相位来获得一系列核磁共振回波信号返回至核磁共振控制台；核磁共振控制台也可以通过指令以及相应的执行机构以改变中心频率的方式或者改变磁体、探头与被测物体的相对位置的方式来产生不同位置的核磁共振回波信号并将其返回至核磁共振控制台；核磁共振控制台接收到不同位置的一系列核磁共振回波信号后对所述核磁共振回波信号分析处理，得到衰减系数。
可选地，所述磁共振系统包括磁共振谱仪、射频功放、前置放大器、收发切换模块、磁体模块以及射频探头；磁共振谱仪，用于向机械振动激励装置发送触发信号，所述磁共振谱仪通过射频功放与收发切换模块连接；收发切换模块，用于切换所述磁共振系统的发射状态和接收状态；射频探头，所述射频探头与收发切换模块连接；发射状态下，所述射频探头用于向被测物体发射射频脉冲；接收状态下，所述射频探头用于接收被测物体检测靶位受激发后产生的核磁共振回波信号；磁体模块，用于产生静态梯度磁场对被测物体进行空间定 位。
优选地，收发切换模块通过前置放大器与磁共振谱仪连接；所述振动发生器通过功率放大器与信号发生器连接。
具体地，如图3所示，磁共振谱仪通过射频功放与收发切换开关连接；磁共振谱仪通过前置放大器与收发切换开关连接；磁共振谱仪通过收发切换开关与射频探头连接；所述收发切换模块用于切换所述便携式磁共振系统处于发射状态或接收状态，发射状态下，所述探头发射射频脉冲；接收状态下，所述射频探头用于接收被测物体靶位受激发后产生的核磁共振回波信号。磁共振谱仪与机械振动激励装置通讯；磁共振控制台通过射频功放分别与磁共振谱仪和收发切换开关连接；所述磁体模块设于射频探头后侧；被测物体设于射频探头与机械振动激励装置的传动杆之间；传动杆将机械振动激励装置的振动传给被测物体，使被测物体在磁体模块的梯度磁场中作简谐振动。
优选地，若使用静态磁场，所述磁共振谱仪不设梯度控制模块，因此也无需设置相应的梯度线圈。磁体模块设有单边磁体，背面连接设有磁轭，背面磁场强度迅速衰减，所述单边磁体产生一个静态磁场，所述静态磁场在ROI范围内存在AP-LR平面内的线性或近似线性梯度，在ROI范围之外，磁场均匀地迅速衰减；磁体模块的磁场分布如图6所示。
可选地，若使用可控梯度磁场，如图4所示，所述磁共振系统还包括梯度系统；所述梯度系统包括梯度放大器和梯度线圈；所述梯度放大器与磁共振谱仪通讯，梯度放大器与梯度线圈连接；所述梯度线圈设于射频探头和磁体模块之间，用于对被测物体产生可控梯度磁场。
梯度系统由梯度放大器和梯度线圈组成，由磁共振谱仪控制，经由梯度放大器将信号放大后由梯度线圈在被测物体所在空间内形成梯度磁场；本实施方式中除脉冲序列和静态梯度磁场配合进行运动编码外，脉冲序列也可与梯度系统配合，利用梯度线圈产生的可控梯度磁场来进行运动编码。
优选地，所述磁共振谱仪设有发射和门控单向信号通路，所述磁共振谱仪通过发射和门控单向信号通路与射频功放连接；所述磁共振谱仪通过收发转换门控与收发切换开关连接，所述射频功放将发射信号放大后与收发切换开关连接，所述收发切换开关与所述射频探头连接。
可选地，机械振动激励装置包括信号发生器、功率放大器和振动发生器；信号发生器，用于接收磁共振谱仪发出的触发信号并根据所述触发信号驱动振动发生器产生简谐振动；振动发生器，所述振动发生器与传动杆连接；所述振动发生器通过传动杆作用于被测物体使所述被测物体产生简谐振动。
优选地，所述信号发生器为波形发生器，波形发生器向功率放大器发送50HZ正弦波进行放大，振动功率放大器与信号发生器连接，信号发生器与所述磁共振谱仪连接，接收磁共振谱仪发出的触发信号由信号发生器传递至振动发生器，振动发生器驱动传动杆产生简谐振动；所述简谐振动器经由传动杆紧贴在被测物质邻近表面上产生振动后在其内部产生剪切波，所述剪切波在AP方向上传播，引起组织内质点在LR方向上做简谐振动，所述核磁共振控制台与所述磁共振谱仪连接，控制运行磁共振脉冲序列指令，并接收磁共振谱仪采集到的核磁共振回波信号，完成实时数据处理。
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、系统、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(系统)、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. 剪切波衰减系数测量方法，其特征在于：包括：向振动状态稳定的被测物体施加核磁共振脉冲序列，并配合静态或可控梯度磁场进行运动编码，以检测所述被测物体至少两个不同位置的核磁共振回波信号，分析处理所述核磁共振回波信号得到剪切波衰减系数。
  2. 根据权利要求1所述的剪切波衰减系数测量方法，其特征在于：所述向振动状态稳定的被测物体施加核磁共振脉冲序列，并配合静态或可控梯度磁场进行运动编码，以检测所述被测物体至少两个不同位置的核磁共振回波信号，
    包括：向作简谐振动的、处于梯度磁场中的被测物体施加90°射频脉冲，根据振动源的频率确定至少一个180°射频脉冲的施加时刻并于该时刻向所述振动状态稳定的被测物体施加所述至少一个180°射频脉冲。
  3. 根据权利要求2所述的剪切波衰减系数测量方法，其特征在于：所述测量所述被测物体至少两个不同位置的核磁共振回波信号，包括检测所述被测物体不同中心频率的核磁共振回波信号；
    或包括检测磁体和/或探头与所述被测物体的不同位置处的核磁共振回波信号。
  4. 根据权利要求3所述的剪切波衰减系数测量方法，其特征在于：所述测量所述被测物体至少两个不同位置的核磁共振回波信号，包括对每一个位置等间隔的调整振动源的初始相位用以获取该位置一系列的核磁共振回波信号。
  5. 根据权利要求4所述的剪切波衰减系数测量方法，其特征在于：所述对每一个位置等间隔的调整振动源的初始相位，包括等间隔的调整所述振动源的初始相位，所述间隔大于2π。
  6. 根据权利要求1-5任意一项所述的剪切波衰减系数测量方法，其特征在于：所述分析处理所述核磁共振回波信号得到剪切波衰减系数，包括：
    设S1(θ,n)为在第一位置采集到的核磁共振回波信号，S2(θ,n)为在第 二位置采集到的核磁共振回波信号，θ表示振动源的初始相位，第二维n表示回波的点数；
    分别对S1(θ,n)和S2(θ,n)的第二维做一维傅里叶变换，取最低频部分的相位，分别得到
    Figure PCTCN2020130245-appb-100001
    (θ)和
    Figure PCTCN2020130245-appb-100002
    (θ)；
    分别对
    Figure PCTCN2020130245-appb-100003
    (θ)和
    Figure PCTCN2020130245-appb-100004
    (θ)做一维相位反卷折运算；
    分别计算
    Figure PCTCN2020130245-appb-100005
    和
    Figure PCTCN2020130245-appb-100006
    即分别计算
    Figure PCTCN2020130245-appb-100007
    (θ)和
    Figure PCTCN2020130245-appb-100008
    (θ)的峰值，得到
    Figure PCTCN2020130245-appb-100009
    Figure PCTCN2020130245-appb-100010
    计算第一位置和第二位置处剪切波振幅
    Figure PCTCN2020130245-appb-100011
    Figure PCTCN2020130245-appb-100012
    式(5)和(6)中，G为运动敏感梯度，γ为拉莫尔频率，T为剪切波振动周期，N为在整个运动编码持续时间内剪切波的周期数目；
    按以下公式(7)运算出剪切波在组织内传播的衰减系数值
    Figure PCTCN2020130245-appb-100013
    式(7)中α是衰减系数，r 1是第一位置距振源距离，r 2是第二位置距振源距离。
  7. 一种用于实现权利要求1-6任意一项所述的剪切波衰减系数测量方法的测量系统，其特征在于：包括
    磁共振系统，用于按照核磁共振脉冲序列指令发射射频脉冲，定位被测物 体空间位置，用于接收核磁共振回波信号；
    机械振动激励装置，用于接收所述磁共振系统发出的射频脉冲信号并根据所述信号使被测物体产生简谐振动；
    核磁共振控制台，控制磁共振系统运行核磁共振脉冲序列指令，接收磁共振系统采集到的核磁共振回波信号，对所述核磁共振回波信号分析处理。
  8. 根据权利要求7所述的测量系统，其特征在于：所述磁共振系统包括磁共振谱仪、射频功放、前置放大器、收发切换模块、磁体模块以及射频探头；
    磁共振谱仪，用于向机械振动激励装置发送触发信号，所述磁共振谱仪通过射频功放与收发切换模块连接；
    收发切换模块，用于切换所述磁共振系统的发射状态和接收状态；
    射频探头，所述射频探头与收发切换模块连接；发射状态下，所述射频探头用于向被测物体发射射频脉冲；接收状态下，所述射频探头用于接收被测物体检测靶位受激发后产生的核磁共振回波信号；
    磁体模块，用于产生静态梯度磁场对被测物体进行空间定位。
  9. 根据权利要求8所述的测量系统，其特征在于：所述机械振动激励装置包括信号发生器、功率放大器和振动发生器；
    信号发生器，用于接收磁共振谱仪发出的触发信号并根据所述触发信号驱动振动发生器产生简谐振动；
    振动发生器，所述振动发生器与传动杆连接；所述振动发生器通过传动杆作用于被测物体使所述被测物体产生简谐振动。
  10. 根据权利要求9所述的测量系统，其特征在于：所述收发切换模块通过前置放大器与磁共振谱仪连接；所述振动发生器通过功率放大器与信号发生 器连接。
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