Simultaneous homologous loading module, material mechanics property measuring device and method

Abstract

The application discloses a simultaneous homogenous loading module, and the loading module is used for exciting homogenous shear waves propagating in at least two directions in the X-Z plane in the medium at one time and inducing the shear waves on the surface or in the medium. The loading module is suitable for dynamic elastic imaging, and can excite homogenous shear waves propagating in multiple directions by using dynamic load to excite the medium, has strong adaptability to the shape and structure of the medium, can in-situ characterize the properties of the medium, is suitable for non-uniform medium, and can improve the signal-to-noise ratio of the measurement result to some extent, thereby improving the accuracy and stability of the measurement result. The application further provides a material mechanics property measuring device and method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soft material mechanics property measurement, in particular to a simultaneous homologous loading module, a material mechanics property measurement device and a method. BACKGROUND

[0002] Soft material mechanics property characterization: for a long time, the mechanics property of soft material has been widely concerned in the fields of biomedical engineering, material science and engineering, soft matter science, chemistry and mechanics. Different from traditional metal materials, soft material has a low elastic modulus and will produce highly nonlinear small deformation behavior under external excitation. The mechanics property of many soft materials is inhomogeneous and anisotropic, and the mechanics property is sensitive to the environment, so it is of great significance to characterize the mechanics property of different positions and different directions of soft material in situ.

[0003] Elastic imaging method: human tissue is a typical soft material, and its mechanics property is related to the health condition of human body. Many diseases, such as atherosclerosis, tumor and pulmonary fibrosis, will cause the change of mechanics property of human tissue, so by measuring the mechanics property of human tissue, some diseases can be diagnosed. This method has a long history, and palpation is a typical example. With the development of medical technology, people pay more and more attention to the non-invasive and quantitative characterization of soft tissue. Due to the low modulus and low elastic wave velocity of soft tissue, the visualization of elastic wave propagation can be easily realized by combining with the rapid development of ultrafast imaging technology in recent years, by which the mechanics property of soft tissue can be effectively tracked and inverted. This method is called elastic imaging method. Typical elastic imaging methods include harmonic elastic imaging and transient wave elastic imaging. In the monitoring of pathological process and the evaluation of tissue damage, elastic imaging is gradually beginning to stand out with its unique advantages.

[0004] Excitation design (i.e. loading design) in elastic imaging: in general, elastic imaging methods can be divided into Figure 14Four key steps in the four key steps. One is to use the appropriate internal / external mechanical excitation to excite the soft tissue to make the tissue produce various deformations. Different excitation methods provide greater freedom for the development of corresponding elastic imaging methods, so the design of the excitation method is one of the most active research directions in the field of elastic imaging. The response of soft material or biological soft tissue to different mechanical loads is different, and the medical imaging means selected to detect the response of the tissue is also different. The mechanical load can be compression load, mechanical vibration, acoustic radiation force (ARF) from the outside, or physiological activity such as pulse wave, physiological noise from the human body itself. According to the different excitation methods, the elastic imaging method is often divided into static elastic imaging and dynamic elastic imaging. In static elastic imaging, the load used to cause tissue deformation is generally static or quasi-static, and the inertia effect can be ignored. Dynamic elastic imaging uses dynamic load to excite soft tissue, which generally excites elastic waves inside the soft tissue.

[0005] Focusing on the inversion of the mechanical properties of soft materials through surface / interface waves, the existing technical solutions can excite soft tissue to induce elastic waves inside the soft material, but there are some limitations:

[0006] First, the shear waves induced in the medium are all transverse shear waves with polarization direction and propagation direction perpendicular to each other, and the composition is single, which can only reflect part of the mechanical properties of the medium.

[0007] Second, the induced shear wave can only propagate in the direction parallel to the arrangement of the ultrasonic transducer, so a single excitation can only invert the mechanical properties of the material in one direction. If multiple excitations are performed to measure the mechanical properties in multiple directions, it is difficult to ensure the consistency of the position during the two measurements. For non-uniform media, it is difficult to accurately measure the mechanical properties of the medium, especially in the case of in vivo, the physiological state changes every moment (breathing, heartbeat, etc.), especially when checking children, children are difficult to constrain themselves to make themselves in the same state twice. At the same time, for some slender structures, due to the limitation of the propagation direction, it is difficult to measure the mechanical properties of the foregoing method.

[0008] Third, although some existing technologies have high signal-to-noise ratio in the direction parallel to the arrangement of the ultrasonic transducer, the signal-to-noise ratio in other directions is weak, which will affect the measurement result and lead to inaccurate measurement result. SUMMARY

[0009] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, one object of the present application is to propose a simultaneous homologous loading module, which is highly adaptable to the medium; can characterize the properties of the medium in situ, and is suitable for non-uniform media; can improve the accuracy and stability of the measurement result.

[0010] According to the first aspect of the present application, the simultaneous and homogeneous loading module is used to excite the shear waves in the medium and induce the shear waves propagating in at least two directions in the X-Z plane on the surface or inside of the medium.

[0011] According to the first aspect of the present application, the simultaneous and homogeneous loading module is used to excite the shear waves in the medium and induce the shear waves propagating in at least two directions in the X-Z plane on the surface or inside of the medium.

[0012] In some embodiments, the shear waves propagating in at least two directions in the X-Z plane include the shear waves propagating in the direction perpendicular to the polarization direction in the X-Z plane and the shear waves propagating in the same direction as the polarization direction.

[0013] In some embodiments, the loading module is used to apply the pulse excitation at different positions in the medium, and the shear waves generated by the pulse excitation at different positions interfere with each other to induce the shear waves propagating in at least two directions in the X-Z plane on the surface or inside of the medium.

[0014] In some embodiments, the loading module is a non-focusing loading module used to apply one or more energy concentration zones on the surface or inside of the medium, the energy concentration zone has a specific size greater than zero in the X direction, and the shear wave array generated by the energy concentration zone interferes in space to induce the shear waves propagating in at least two directions in the X-Z plane on the surface or inside of the medium.

[0015] In some embodiments, the time and space of the plurality of energy concentration zones are arbitrarily distributed.

[0016] In some embodiments, the non-focusing loading module is a non-focusing mechanical loading module or a non-focusing ultrasonic loading module.

[0017] In some embodiments, the non-focusing mechanical loading module includes a first modal exciter and an excitation head having a specific size in the X direction, and the excitation head is connected to the first modal exciter.

[0018] In some embodiments, the non-focusing ultrasonic loading module includes a first ultrasonic transducer and a first acoustic lens, the first ultrasonic transducer is used to emit a plane wave, and the first acoustic lens is used to converge the plane wave to form at least one energy concentration zone on the surface or inside of the medium; or the non-focusing ultrasonic loading module includes a second ultrasonic transducer, and the modulated ultrasonic wave emitted by the second ultrasonic transducer forms an energy concentration zone on the surface or inside of the medium.

[0019] In some embodiments, the loading module is a focused loading module, which is configured to apply a plurality of excitation points inside or on the surface of the medium, the X coordinates of the plurality of excitation points are different from each other, and the shear wave fronts generated by the plurality of excitation points interfere with each other in space, thereby inducing shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium.

[0020] In some embodiments, the plurality of excitation points are randomly distributed in time and space.

[0021] In some embodiments, the focused loading module is a focused mechanical loading module or a focused ultrasonic loading module.

[0022] In some embodiments, the focused mechanical loading module comprises a plurality of second modal exciters arranged along the X direction.

[0023] In some embodiments, the focused ultrasonic loading module comprises a third ultrasonic transducer configured to apply a plurality of excitation points at different positions in the X direction on the surface or inside the medium in sequence, or the focused ultrasonic loading module comprises a fourth ultrasonic transducer and at least one fourth acoustic lens, the fourth ultrasonic transducer is configured to emit a plane wave, and each fourth acoustic lens is configured to converge the plane wave to form an excitation point at a different position on the surface or inside the medium.

[0024] The second aspect of the present application further provides a material mechanical property measuring device.

[0025] The material mechanical property measuring device according to the second aspect of the present application comprises:

[0026] a loading module, which is the simultaneous and homogeneous loading module according to any one of the embodiments of the first aspect of the present application, and is configured to excite simultaneously and homogeneously inside the medium and induce shear waves propagating in at least two directions in the X-Z plane on the surface or inside the medium;

[0027] a signal acquisition module, which is configured to acquire wave front information on the surface or inside the medium, and extract two-point motion information on the surface of the medium from the wave front information;

[0028] a signal processing module, which is configured to process the motion information, thereby obtaining characteristic information of the motion information, and obtain the mechanical properties of the material to be measured through the characteristic information;

[0029] a display module, which is configured to output the mechanical properties.

[0030] A control module is configured to control the simultaneous homologous loading module, the signal acquisition module, the signal processing module and the display module.

[0031] The material mechanical property measuring device according to the second aspect of the present application can simultaneously excite shear waves that are homologous and propagate in multiple directions, is highly adaptable to the shape and structure of a medium, can in-situ characterize the properties of the medium, is applicable to non-uniform materials, can improve the signal-to-noise ratio of the measurement results to some extent, thereby improving the accuracy and stability of the measurement results, can directly measure the layered structure of the medium to some extent, can acquire both surface waves and interface waves on the interface of a layered medium, and can automatically determine the excitation mode and the parameters of the acquisition system according to the properties of the medium, thereby expanding the range of materials that can be characterized and making the measurement results more accurate.

[0032] In some embodiments, the control module controls the frequency, amplitude and duration of the loading module.

[0033] In some embodiments, the signal acquisition module is composed of at least two single-crystal ultrasonic probes or at least one polycrystal ultrasonic probe.

[0034] The third aspect of the present application further provides a material mechanical property measuring method.

[0035] The material mechanical property measuring method according to the third aspect of the present application is measured by using the material mechanical property measuring device according to any one of the second aspect of the present application, and includes the following steps:

[0036] S1: selecting a region to be measured of a medium;

[0037] S2: setting the excitation frequency, amplitude, period and position of the loading module;

[0038] S3: applying excitation to the medium and acquiring wavefront information;

[0039] S4: inverting the mechanical properties of the material by using the wavefront information and displaying.

[0040] The material mechanical property measuring method according to the third aspect of the present application can simultaneously excite shear waves that are homologous and propagate in multiple directions, is highly adaptable to the shape and structure of a medium, can in-situ characterize the properties of the medium, is applicable to non-uniform materials, can improve the signal-to-noise ratio of the measurement results to some extent, thereby improving the accuracy and stability of the measurement results, can directly measure the layered structure of the medium to some extent, can acquire both surface waves and interface waves on the interface of a layered medium, and can automatically determine the excitation mode and the parameters of the acquisition system according to the properties of the medium, thereby expanding the range of materials that can be characterized and making the measurement results more accurate.

[0041] In some embodiments, the step S3 of applying excitation to the medium and collecting wavefront information specifically comprises the following sub-steps: S301: after the step S2 is completed, the loading module applies excitation to the medium to generate shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium;

[0042] S302: the signal collection module collects wavefront information of the shear waves;

[0043] S303: extracting motion information of two points on the surface of the medium from the wavefront information;

[0044] S304: checking the motion information measured at each excitation frequency of the loading module to determine whether the motion information measured at all excitation frequencies of the loading module is reliable;

[0045] S305: recording parameters of the excitation frequency, amplitude, period and position corresponding to the reliable motion information.

[0046] In some embodiments, the motion information in step S303 includes displacement, velocity and acceleration of particles in the medium over time.

[0047] In some embodiments, the checking of the motion information measured at each excitation frequency of the loading module in step S304 specifically includes checking whether the signal-to-noise ratio level meets the requirements and whether the signal attenuation level meets the requirements, and if both the signal-to-noise ratio level and the signal attenuation level meet the requirements, the motion information is reliable; if one or both of the signal-to-noise ratio level and the signal attenuation level do not meet the requirements, the motion information is unreliable, then adjusting the amplitude, period, position or / and the size of the position of the corresponding excitation frequency of the loading module, and then repeating steps S301 to S304.

[0048] In some embodiments, the signal-to-noise ratio is defined as follows: selecting 100 points with the largest wavefront amplitude, taking the average of their amplitudes as the usable signal; setting the voltage of the signal generator of the loading module to 0 in the control module, taking the standard deviation of the motion amplitudes of all points in the entire ROI region collected at this time as the noise; taking the ratio of the usable signal to the noise, taking the logarithm to the base 10 and multiplying by 0 as the signal-to-noise ratio; when the signal-to-noise ratio is greater than or equal to the signal-to-noise ratio threshold set by the collection module, the signal-to-noise ratio level meets the requirements.

[0049] In some embodiments, the signal attenuation level is the intensity ratio of the usable signal of the farthest measuring point from the excitation position in the medium to be measured to the usable signal at the excitation position as the signal attenuation level; when the signal attenuation level is less than the signal attenuation threshold, the signal attenuation level is too strong and does not meet the requirements.

[0050] In some embodiments, the step of using the wave front information to inverse the mechanical properties of the material in step S4 specifically comprises the following sub-steps:

[0051] S401: wave front information analysis: under the premise that the motion information is reliable, the motion information of the particles in two different directions is extracted from the measured wave front information, and the dispersion curve of the motion information is obtained from the motion information;

[0052] S402: determining whether the medium is an elastic medium or a viscous medium;

[0053] S405: if it is determined that the medium is an elastic medium, the mechanical properties or stress distribution of the medium in different directions is inverse from the motion information and saved in the control module;

[0054] S406: if it is determined that the medium is a viscous medium, the dispersion curve in step S401 is directly analyzed, the viscous parameters of the medium are measured by a fitting method according to the surface wave dispersion relationship of the viscoelastic material constitutive, and the viscous parameters are saved in the control module.

[0055] In some embodiments, the determination of whether the medium is an elastic medium or a viscous medium in step S402 is achieved by selecting a specific index to measure the degree of viscoelastic dispersion of the medium.

[0056] In some embodiments, the specific index is the ratio of the phase velocity of the shear wave at a high excitation frequency to the phase velocity of the shear wave at a low excitation frequency, and the medium is determined to be an elastic medium or a viscous medium by comparing the ratio of the phase velocities with a viscoelastic threshold value. If the ratio of the phase velocities is greater than the viscoelastic threshold value, the medium is a viscous medium; if the ratio of the phase velocities is less than or equal to the viscoelastic threshold value, the medium is an elastic medium.

[0057] Additional aspects and advantages of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0058] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the following drawings, in which:

[0059] Figure 1 is a schematic diagram of an excitation mode of a homologous simultaneous loading module of an embodiment of the present application, showing an energy concentration area.

[0060] Figure 2 is a schematic diagram of another excitation mode of a homologous simultaneous loading module of an embodiment of the present application, showing multiple excitation points.

[0061] Figure 3 Schematic diagram of experimental and simulation results of wave fields obtained by applying excitation using a homologous simultaneous loading module according to an embodiment of the present invention, wherein the upper row of pictures are experimental results and the lower row of pictures are simulation results.

[0062] Figure 4 It is a schematic diagram of the velocity space-time field of wavefront propagation measured by applying excitation by the homologous simultaneous loading module of an embodiment of the present invention, wherein the left picture illustrates the velocity space-time field propagating along the X direction, and the right picture illustrates the velocity space-time field propagating along the Z direction.

[0063] Figure 5 Schematic diagram of a non-focused mechanical homologous simultaneous loading module according to an embodiment of the present invention.

[0064] Figure 6 Schematic diagram of another non-focused ultrasound homologous simultaneous loading module according to an embodiment of the present invention.

[0065] Figure 7 It is a schematic diagram of another non-focused ultrasound homologous simultaneous loading module according to an embodiment of the present invention.

[0066] Figure 8 It is a schematic diagram of a focusing mechanical homologous simultaneous loading module according to an embodiment of the present invention.

[0067] Figure 9 It is a schematic diagram of another focused ultrasound homologous simultaneous loading module according to an embodiment of the present invention.

[0068] Figure 10 It is a schematic diagram of another focused ultrasound homologous simultaneous loading module according to an embodiment of the present invention.

[0069] Figure 11 Schematic diagram of a device for measuring mechanical properties of materials according to an embodiment of the present invention.

[0070] Figure 12 4 is a flow chart of a method for measuring mechanical properties of materials according to an embodiment of the present invention.

[0071] Figure 13 It is the velocity space-time field of wavefront propagation measured by a simulation experiment using the material mechanical property measurement method according to an embodiment of the present invention on skeletal muscle.

[0072] Figure 14 This is a schematic diagram of the existing elastography process.

[0073] Reference numerals:

[0074] Loading module 1; first modal exciter 101; excitation head 102; first ultrasonic transducer 103; first acoustic lens 104; second ultrasonic transducer 105; second modal exciter 106; third ultrasonic transducer 107; fourth ultrasonic transducer 108; fourth acoustic lens 109; signal acquisition module 2; signal processing module 3; display module 4; control module 5; medium A; energy concentration area M; excitation point N; shear wave front L. DETAILED DESCRIPTION

[0075] Embodiments of the present application are described below in detail with reference to the accompanying drawings, wherein the same or similar components are denoted by the same or similar reference numerals throughout the drawings. The embodiments described below by reference to the drawings are exemplary only, and are intended to explain the present application, and should not be understood as limiting the present application.

[0076] The embodiments of the present application are described below in conjunction with Figures 1 to 13 .

[0077] As shown in Figures 1 to 10 , the first aspect of the present application proposes a simultaneous homologous loading module 1.

[0078] As shown in Figures 1 to 10 , the simultaneous homologous loading module 1 according to the first aspect of the present application is used to excite simultaneously homologous and induce shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium A.

[0079] It should be noted that the medium A here is a soft material medium, such as a biological soft tissue. The term "one-time excitation" here refers to the excitation of all the loading positions in the selected region of the medium A, for example, as shown in Figure 1 , Figure 6 and Figure 7 , for a loading position in the selected region, if the excitation applied to the loading position forms an energy concentration area M (i.e., a focusing area) with a specific size in the X direction greater than zero, it is considered that one-time excitation is completed; for another example, as shown in Figure 2 , Figure 9 and Figure 10 , for a plurality of loading positions in the selected region, if the excitation at the excitation points N (i.e., focusing points) of the plurality of loading positions is completed, it is considered that one-time excitation is completed, i.e., simultaneous excitation is completed. The plurality of excitation points N can be excited simultaneously (see Figure 10 ) or not simultaneously (see Figure 9) is completed. The same source here means that the shear waves propagating in at least two directions in the XZ plane all come from the same wave source in medium A, that is, the same wave source propagates in at least two directions in the XZ plane (such as Figure 3 and Figure 4 As shown in Figure 2), shear waves propagating in different directions reflect different mechanical properties of medium A. Here, the XZ plane can be referred to as Figure 1 、 Figure 2 、 Figure 5 、 Figure 8 and Figure 9 The plane shown in .

[0080] The simultaneous homologous loading module 1 according to the first aspect of the present invention is suitable for dynamic elastic imaging. It uses a dynamic load to excite the medium A, and can simultaneously excite homologous shear waves that propagate in multiple directions. It has strong adaptability to the shape and structure of the medium A; it can perform in-situ characterization of the properties of the medium A and is suitable for non-uniform materials; it can improve the signal-to-noise ratio of the measurement results to a certain extent, thereby improving the accuracy and stability of the measurement results.

[0081] In some embodiments, the shear waves propagating along at least two directions in the XZ plane include shear waves propagating perpendicular to the polarization direction in the XZ plane and shear waves propagating in the same direction as the polarization direction. It is understood that the two different shear waves exhibit different mechanical properties, and in terms of acquisition methods, typical acquisition modules are only sensitive to particle motion along the X direction. Therefore, only shear waves propagating along the Z direction with polarization in the same direction as the propagation direction can be acquired.

[0082] In some embodiments, the loading module 1 applies pulse excitation at different positions in the medium A. The shear waves generated by the pulse excitation at different positions interfere with each other, thereby inducing shear waves propagating in at least two directions in the XZ plane inside or on the surface of the medium A. Here, the different positions in the medium A can be understood as the loading areas or different points of the medium A. For example, the loading position of the selected area to be tested of the medium A has one or more loading areas, each of which has a specific size load greater than zero in the X direction. The excitation applied by the loading module 1 to each loading area respectively forms an energy concentration area M with a specific size greater than zero in the X direction; Figure 1 、 Figure 6 and Figure 7 As shown in FIG, a non-focused energy concentration area M is schematically shown. In other words, the energy concentration area M is a way to achieve excitation. Since the energy concentration area M has a specific size in the X direction, the generated shear wave front L interferes in space, thereby inducing shear waves propagating in at least two directions in the XZ plane inside or on the surface of medium A. For another example, the loading position of the selected test area of ​​medium A is multiple points, and the excitation points N (i.e., focusing points) at the multiple points (such asFigure 2 、 Figure 9 and Figure 10 are all completed, a single excitation, i.e. simultaneous excitation, is realized. The excitation point N is another way to realize excitation, and the shear wave fronts generated by multiple excitation points N interfere in space, thereby inducing shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium A.

[0083] In some embodiments, the loading module 1 is a non-focusing loading module (as shown in Figures 5 to 7 ), which is used to apply one or more energy concentration zones M inside or on the surface of the medium A. The energy concentration zone M has a specific size greater than zero in the X direction, and the shear wave fronts L generated thereby interfere in space, thereby inducing shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium A. That is, the non-focusing loading module 1 can be used to apply an energy concentration zone M inside or on the surface of the medium A.

[0084] In some embodiments, the time and space of the multiple energy concentration zones M are arbitrarily distributed. That is, the multiple energy concentration zones M can be applied simultaneously or at different times, and the relative positions of the individual energy concentration zones M are arbitrary, even if they are applied at the same position.

[0085] In some embodiments, the non-focusing loading module 1 is a non-focusing mechanical loading module (as shown in Figure 5 ) or a non-focusing ultrasonic loading module (as shown in Figure 6 and Figure 7 ).

[0086] For example, as shown in Figure 5 , the non-focusing mechanical loading module 1 includes a first modal exciter 101 and an excitation head 102 having a specific size in the X direction, and the excitation head 102 is connected to the first modal exciter 101. Through the first modal exciter and the excitation head, excitation can be applied to the medium A to form an energy concentration zone M.

[0087] For another example, as shown in Figure 6 , the non-focusing ultrasonic loading module 1 includes a first ultrasonic transducer 103 for emitting a plane wave and a first acoustic lens 104 for converging the plane wave to form at least one energy concentration zone M inside or on the surface of the medium A.

[0088] For another example, as shown in Figure 7 , the non-focusing ultrasonic loading module 1 includes a second ultrasonic transducer 105 for emitting a modulated ultrasonic wave to form an energy concentration zone M inside or on the surface of the medium A. Through this structure, excitation can be applied to the medium A to form an energy concentration zone M.

[0089] In some embodiments, the loading module 1 is a focused loading module (as shown in Figures 8 to 10 for applying multiple excitation points N inside or on the surface of the medium A, the X coordinates of the multiple excitation points N are different from each other, and the shear wave fronts generated by the multiple excitation points N interfere with each other in space, thereby inducing shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium A. That is, the focused loading module 1 can be used to apply multiple excitation points N inside or on the surface of the medium A.

[0090] In some embodiments, the multiple excitation points N are arbitrarily distributed in time and space. That is, the application of each excitation point N can be simultaneous or not, and the order of application in space can be from left to right, from right to left, from the middle to the two sides, etc., and the spatial distribution can also be arbitrary as long as the X coordinates of all excitation points N are not the same number.

[0091] In some embodiments, the focused loading module 1 is a focused mechanical loading module (as shown in Figure 8 ) or a focused ultrasonic loading module (as shown in Figure 9 and Figure 10 ).

[0092] For example, as shown in Figure 8 , the focused mechanical loading module 1 includes multiple second modal exciters 106 arranged along the X direction. Each second modal exciter 106 corresponds to multiple loading points of the medium A arranged along the X direction, and simultaneously or not simultaneously applies an excitation point N. When all the excitation points N are completed, it is considered that one excitation is completed, that is, simultaneous excitation. That is, the multiple second modal exciters 106 can be used to apply multiple excitation points N to the medium A.

[0093] For another example, as shown in Figure 9 , the focused ultrasonic loading module 1 includes a third ultrasonic transducer 107, which can be one. The third ultrasonic transducer 107 is used to apply multiple excitation points N of different positions along the X direction inside or on the surface of the medium A in sequence. When all the excitation points N are completed, it is considered that one excitation is completed, that is, simultaneous excitation. That is, the multiple second modal exciters 106 can be used to apply multiple excitation points N to the medium A.

[0094] For another example, as shown in Figure 10As shown, the focused ultrasound loading module 1 comprises a fourth ultrasonic transducer 108 for emitting plane waves and at least one fourth transducer, and a fourth acoustic lens 109 for converging the plane waves to form excitation points N at different positions on the surface or inside the medium A, respectively. Each excitation point N is considered as one excitation, i.e. simultaneous excitation. That is, the medium A can be excited by multiple excitation points N through the multiple second modal exciters 106.

[0095] As shown in the drawings, Figure 11 The second aspect of the present application further provides a material mechanical property measuring device.

[0096] As shown in the drawings, Figure 11 The material mechanical property measuring device according to the second aspect of the present application comprises a loading module 1, a signal acquisition module 2, a signal processing module 3, a display module 4 and a control module 5.

[0097] The loading module 1 is the simultaneous and homologous loading module 1 according to any one of the embodiments of the first aspect of the present application, which is used to excite homologous shear waves propagating in at least two directions along the X-Z plane inside the medium A at one time. The loading module 1 comprises a signal generator, and the control module 5 adjusts the parameters (such as frequency, voltage amplitude, cycle number) of the signal generator to control the frequency, amplitude and duration of the loading module 1. The loading module 1 is suitable for dynamic elastography, and can excite homologous shear waves propagating in multiple directions at one time by using dynamic load to excite the medium A, has strong adaptability to the shape and structure of the medium A; can characterize the properties of the medium A in situ, and is suitable for non-uniform materials; and can improve the signal-to-noise ratio of the measurement results to some extent, thereby improving the accuracy and stability of the measurement results.

[0098] The signal acquisition module 2 is used to acquire the wave front information on the surface or inside the medium A, and extract the motion information of two points on the surface of the medium A from the wave front information, so as to track the propagation process of the motion signal caused by the loading of the loading module 1. The signal acquisition module can use an ultrasonic transducer.

[0099] The signal processing is used to process the motion information acquired by the signal acquisition module 2, so as to obtain the characteristic information of the motion information propagation, such as phase velocity, group velocity, dispersion curve, etc., and obtain the mechanical properties of the material to be measured through the characteristic information of the motion information propagation. The mechanical properties herein include the mechanical properties of the medium A, such as elasticity, viscoelasticity, and pre-stress.

[0100] The display module 4 is used to output the mechanical properties. That is, the display module 4 can be composed of a display screen and / or a printer, and is responsible for displaying or printing the measured mechanical properties in the form of a report or a chart.

[0101] The control module 5 is used for controlling the operation of the simultaneous homologous loading module 1, the signal acquisition module 2, the signal processing module 3 and the display module 4. The loading module 1 is controlled by the control module 5 to excite homologous shear waves propagating in at least two directions in the X-Z plane inside the medium A and on the surface of the medium A, the signal acquisition module 2 is started by the control module 5 to acquire the motion information of the surface of the medium A, the signal processing module 3 processes the motion information to obtain the mechanical properties of the medium A, and the display module 4 outputs the results.

[0102] The material mechanical property measuring device according to the second aspect of the present application can excite homologous shear waves propagating in multiple directions simultaneously, is adaptable to the shape and structure of the medium A, can characterize the properties of the medium A in situ, is suitable for non-uniform materials, can improve the signal-to-noise ratio of the measurement results to some extent, thereby improving the accuracy and stability of the measurement results, can directly measure the layered structure of the medium A to some extent, can acquire both surface waves and interface waves on the interface of the layered medium A, can automatically determine the excitation mode and the parameters of the acquisition system according to the properties of the medium A, thereby expanding the range of materials that can be characterized and making the measurement results more accurate.

[0103] In some embodiments, the control module 5 controls the frequency, amplitude and duration of the loading module 1 by adjusting the parameters (such as frequency, voltage amplitude, number of cycles) of the signal generator of the loading module 1.

[0104] In some embodiments, the signal acquisition module 2 is composed of at least two single-crystal ultrasonic probes or at least one polycrystal ultrasonic probe. This facilitates the acquisition of motion information of at least two points in space for mechanical property analysis.

[0105] As shown in Figure 12 The third aspect of the present application further provides a material mechanical property measurement method.

[0106] The material mechanical property measurement method according to the third aspect of the present application is measured by using the material mechanical property measurement device according to any one of the embodiments of the second aspect of the present application, and includes the following steps:

[0107] S1: Selecting a region of interest (ROI) of the medium A. It can be understood that the ROI is selected according to the requirements and the properties of the medium A, which can be judged by naked eye observation, ultrasonic image, material science knowledge, etc. For example, for skeletal muscle, the part far away from the tendon should be selected as the ROI as much as possible; for non-uniform medium A, multiple parts should be selected as the ROI; and under other conditions, the position with the strongest ultrasonic reflection is selected as the ROI.

[0108] S2: set the excitation frequency, amplitude, period and position of the loading module 1. It can be understood that after the determination of the to-be-measured region of the medium A in step S1, the excitation frequency, amplitude and period of the loading module 1 are set by the control module 5 according to the properties of the medium A and the relevant standards, for example, for biological soft tissue, the amplitude size can be set according to the clinical standard of shear wave elastography to avoid damage to the tissue. At the same time, the appropriate loading position is selected according to the size and shape of the to-be-measured region to ensure that the shear waves in each direction obtained by excitation can propagate in the to-be-measured region to collect the wave front information.

[0109] S3: apply excitation to the medium A and collect the wave front information. It can be understood that after step S2 is completed, the control module 5 starts the loading module 1, and the loading module 1 applies excitation to the loading position of the to-be-measured region to induce shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium A; the control module 5 controls the start of the signal collection module 2, and the signal collection module 2 collects the wave front information, extracts the motion information of at least two points in space from the wave front information, and checks the motion information to determine whether the motion information measured at the set excitation frequency is reliable, which is conducive to improving the signal-to-noise ratio of the measurement result to some extent, thereby improving the accuracy and stability of the measurement result.

[0110] S4: invert the mechanical properties of the medium A using the wave front information and display. It can be understood that in step S3, when the motion information is determined to be reliable, the reliable motion information is processed to invert the mechanical properties of the medium A, and the inversion result is output through the display module 4.

[0111] According to the material mechanical property measurement method of the third aspect of the present application, the same source shear waves propagating in multiple directions can be excited at the same time, which is suitable for the shape and structure of the medium A; the properties of the medium A can be characterized in situ, which is suitable for non-uniform materials; the signal-to-noise ratio of the measurement result can be improved to some extent, thereby improving the accuracy and stability of the measurement result; the layered structure of the medium A can be directly measured to some extent; both surface waves and interface waves on the interface of the layered medium A can be collected; the excitation mode and the parameters of the collection system can be automatically determined according to the properties of the medium A, thereby expanding the range of materials that can be characterized and making the measurement result more accurate.

[0112] In some embodiments, the step of applying excitation to the medium and collecting the wave front information in step S3 specifically includes the following sub-steps:

[0113] S301: after step S2 is completed, the loading module 1 applies excitation to the medium A to generate shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium A;

[0114] S302: The signal acquisition module 2 acquires the wave front information of the shear wave;

[0115] S303: Extract the motion information of two points on the surface of medium A from the wave front information;

[0116] S304: Check the motion information measured at each excitation frequency of the loading module 1 to determine whether the motion information measured at all excitation frequencies of the loading module 1 is reliable;

[0117] S305: Record the parameters of the excitation frequency, amplitude, period and position corresponding to the reliable motion information.

[0118] Through steps S301 and S305, it can be determined that the motion information measured at all excitation frequencies of the loading module 1 is reliable, which can improve the accuracy of the measurement results.

[0119] In some embodiments, the motion information in step S303 includes the displacement, velocity and acceleration of the particles in medium A as a function of time.

[0120] In some embodiments, the checking of the motion information measured at each excitation frequency of the loading module 1 in step S304 specifically includes checking whether the signal-to-noise ratio level meets the requirements and whether the signal attenuation level meets the requirements. If both the signal-to-noise ratio level and the signal attenuation level meet the requirements, the motion information is reliable. If one or both of the signal-to-noise ratio level and the signal attenuation level do not meet the requirements, the motion information is not reliable, and then the amplitude, period, position or / and position size of the corresponding excitation frequency of the loading module 1 is adjusted, and then steps S301 to S304 are repeated.

[0121] In some embodiments, the signal-to-noise ratio is defined as follows: 100 points with the largest wave front amplitude are selected, and the average of the amplitudes of the 100 points is taken as the available motion information. In the control module 5, the voltage of the signal generator of the loading module 1 is set to 0, and the standard deviation of the motion amplitudes of all points in the entire region to be measured collected at this time is taken as the noise. The ratio of the available signal to the noise is taken as the logarithm with base 10 and multiplied by 0 as the signal-to-noise ratio. When the signal-to-noise ratio is greater than or equal to the signal-to-noise ratio threshold set by the acquisition module (for example, the signal-to-noise ratio threshold is 20 dB), the signal-to-noise ratio level meets the requirements. In this way, it can be ensured that the motion information has a high enough signal-to-noise ratio, and the mechanical properties of the material can be accurately inverted according to the wave front information.

[0122] In some embodiments, in materials with strong viscous dissipation, signals attenuate significantly during propagation. If the signal attenuates significantly between two measurement points, the final measurement result can be significantly affected. Therefore, the signal attenuation level is defined as the ratio of the available signal strength at the measurement point farthest from the excitation location in the measured region of medium A to the available signal strength at the excitation location. When the signal attenuation level is less than a signal attenuation threshold (for example, -5dB), the signal attenuation level is considered excessive and does not meet the requirements.

[0123] In some materials with strong viscous dissipation, signals attenuate significantly during propagation. If the signal attenuates significantly between two measurement points, the final measurement result can be significantly affected. To address this, the signal attenuation level is defined as the ratio of the available signal intensity at the measurement point farthest from the excitation location within the ROI to the available signal intensity at the excitation location. A signal attenuation level less than -5dB is considered excessive and the measurement fails.

[0124] When the above-mentioned signal-to-noise ratio level and signal attenuation level fail to meet the requirements under the excitation at a certain excitation frequency, the excitation at a certain excitation frequency needs to be re-measured, and the excitation intensity, position and size of the area to be tested need to be adjusted accordingly. Typically, when the signal-to-noise ratio level does not meet the requirements, the excitation intensity is appropriately increased (to meet clinical safety requirements), or the loading position of the area to be tested is changed / the angle of the signal addition module is adjusted to obtain the strongest acoustic reflection intensity, or the signal-to-noise ratio can be improved by averaging the measurement results of multiple times at the same location; when the signal attenuation level does not meet the requirements, the size of the area to be tested is changed to 1 / 4 of the original size (the length and width are each changed to 1 / 2 of the original size).

[0125] As long as the motion information measured at a certain time has indicators that do not meet the requirements, the parameters must be adjusted and re-measured until the measured motion signals meet the above-mentioned signal-to-noise ratio level and signal attenuation level.

[0126] In some embodiments, in step S4, inverting the mechanical properties of the material using the wavefront information specifically includes the following sub-steps:

[0127] S401: Wavefront information analysis: Under the premise of checking that the motion information is reliable, the measured wavefront information is selected in two different directions to extract the changes in the motion information of the particles in the two directions over time (such as Figure 4 The dispersion curve of motion information is obtained by Fourier transform, wavelet transform and other methods based on the running information.

[0128] S402: Determine whether medium A is an elastic medium or a viscous medium.

[0129] S405: If it is determined that medium A is an elastic medium, the mechanical properties or stress distribution of medium A in different directions are inverted based on the motion information and stored in the control module 5. Figure 4 The motion information shown can be used to measure the material's group velocity using methods such as Radon transform and time offset. A statistical value (such as the mean or median) of the measured group velocity is then used as the measured shear wave velocity. By measuring the shear wave group velocity in different directions, the material's mechanical properties or stress distribution in different directions can be inverted and stored in the control module. The material density and Poisson's ratio must be determined by the tester through manuals or independent experiments. A typical formula is found in Achenbach's monograph.

[0130] like Figure 13 As shown, (a) the picture shows the multi-layered hierarchical structure of skeletal muscle, and the different density of muscle bundles shows non-uniformity. (b) The picture shows the cross-section of skeletal muscle parallel to the fiber direction. Due to the presence of fibroblasts and collagen fibers, the mechanical properties of skeletal muscle show obvious anisotropy. (c) The elastic distribution of the tumor is shown, showing obvious non-uniformity.

[0131] S406: If medium A is determined to be a viscous medium, directly analyze the dispersion curve in step S401, and according to the surface wave dispersion relation of the viscoelastic material constitutive law, measure the viscosity parameters of medium A through fitting method and save them in control module 5.

[0132] Through steps S401 to S406, the mechanical properties of the area to be measured of medium A can be inverted.

[0133] In some embodiments, in step S402 , whether medium A is an elastic medium or a viscous medium is determined by selecting a specific indicator to measure the degree of viscoelastic dispersion of medium A.

[0134] In a highly viscous medium A, the phase velocities of shear waves of different frequencies vary significantly (this is known as viscoelastic dispersion). A metric can be selected to measure the degree of viscoelastic dispersion. Typically, this metric could be the ratio of the phase velocity measured at 1000 Hz to the phase velocity measured at 100 Hz. If this metric exceeds a certain threshold (e.g., the ratio of the two phase velocities exceeds 1.3), medium A is considered highly viscous; otherwise, medium A is considered elastic.

[0135] In some embodiments, the specific indicator is the ratio of the phase velocity of the shear wave at a high excitation frequency to the phase velocity of the shear wave at a low excitation frequency. By comparing the phase velocity ratio with the viscoelastic threshold, it is determined whether medium A is an elastic medium or a viscous medium. If the phase velocity ratio is greater than the viscoelastic threshold, medium A is a viscous medium; if the phase velocity ratio is less than or equal to the viscoelastic threshold, medium A is an elastic medium.

[0136] It should be noted that steps 3.2-3.8 are repeated with different ROIs, and if the mechanical properties measured by each ROI are similar (relative deviation is not more than 20%), the material is considered to be homogeneous, and the display module 4 displays that the material is homogeneous and displays the mechanical parameters of the material on the screen or prints them on the test report; otherwise, the display module 4 displays that the material is not homogeneous and displays the mechanical parameters of the material on the screen or prints them on the test report. (For anisotropic materials such as tumors, skeletal muscles, etc., the mechanical properties measured in different directions are different, as shown in FIG. 6) In-situ measurement is a unique solution of the present patent and should be protected as a key point. Figure 13

[0137] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0138] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements, and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.​

Claims

1. A simultaneous homogenous loading module, characterized in that, The loading module is used for exciting the same source in the medium at one time and inducing shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium. The loading module is used for exciting the same source in the medium at one time and inducing shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium. The loading module is a non-focusing loading module, which is used for applying one or more energy concentration zones in the medium inside or on the surface, the energy concentration zone has a specific size greater than zero in the X direction, and the shear wave array generated by the energy concentration zone interferes in space, thereby inducing shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium. The loading module is a focusing loading module, which is used for applying a plurality of excitation points in the medium inside or on the surface, the X coordinates of the plurality of excitation points are different from each other, and the shear wave array generated by the plurality of excitation points interferes in space, thereby inducing shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium.

2. The simultaneous homogenous loading module of claim 1, wherein, The shear waves propagating in at least two directions in the X-Z plane include shear waves perpendicular to the polarization direction in the X-Z plane and shear waves propagating in the same direction as the polarization direction.

3. The simultaneous homogenous loading module of claim 1, wherein, The time and space of the plurality of energy concentration zones are arbitrarily distributed.

4. The simultaneous homogenous loading module of claim 1, wherein, The non-focusing loading module is a non-focusing mechanical loading module or a non-focusing ultrasonic loading module.

5. The simultaneous homogenous loading module of claim 4, wherein, The non-focusing mechanical loading module includes a first modal vibrator and an excitation head having a specific size in the X direction, and the excitation head is connected to the first modal vibrator.

6. The simultaneous homogenous loading module of claim 4, wherein, The non-focusing ultrasonic loading module includes a first ultrasonic transducer for emitting a plane wave and a first acoustic lens for converging the plane wave to form at least one energy concentration zone on the medium inside or on the surface; or the non-focusing ultrasonic loading module includes a second ultrasonic transducer for emitting a modulated ultrasonic wave to form an energy concentration zone on the medium inside or on the surface.

7. The simultaneous homogenous loading module of claim 1, wherein, The time and space of the plurality of excitation points are arbitrarily distributed.

8. The simultaneous homogenous loading module of claim 1, wherein, The focusing loading module is a focusing mechanical loading module or a focusing ultrasonic loading module.

9. The simultaneous homogenous loading module of claim 8, wherein, The focusing mechanical loading module includes a plurality of second modal vibrators arranged in the X direction.

10. The simultaneous homogenous loading module of claim 8, wherein, The focusing ultrasonic loading module includes a third ultrasonic transducer for sequentially applying a plurality of excitation points at different positions in the X direction on the medium inside or on the surface; or the focusing ultrasonic loading module includes a fourth ultrasonic transducer for emitting a plane wave and at least one fourth acoustic lens for converging the plane wave to form different excitation points at different positions on the medium inside or on the surface.

11. A material mechanical property measurement apparatus, characterized by, The loading module is the simultaneous and same source loading module according to any one of claims 1-10, which is used for exciting the same source in the medium at one time and inducing shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium. ​ A signal acquisition module, configured to acquire wave front information of a medium surface or inside, and extract two-point motion information on the medium surface from the wave front information; A signal processing module, configured to process the motion information to obtain characteristic information of the motion information propagation, and obtain mechanical properties of the material to be measured through the characteristic information; A display module, configured to output the mechanical properties; A control module, configured to control operations of the simultaneous and homogeneous loading module, the signal acquisition module, the signal processing module, and the display module.

12. The material mechanical property measurement apparatus of claim 11, wherein, The control module controls frequency, amplitude, and duration of the loading module.

13. The material mechanical property measurement apparatus of claim 11, wherein, The signal acquisition module is composed of at least two single-crystal ultrasonic probes or at least one polycrystal ultrasonic probe.

14. A method of measuring the mechanical properties of a material, characterized in that, The material mechanical property measurement device is used to measure, including the following steps: S1: selecting a region to be measured of a medium; S2: setting excitation frequency, amplitude, period, and position of the loading module; S3: applying excitation to the medium and acquiring wave front information; S4: inverting mechanical properties of the material by using the wave front information and displaying.

15. The method of measuring the mechanical properties of a material of claim 14, wherein, The step S3 of applying excitation to the medium and acquiring wave front information specifically includes the following sub-steps: S301: after the step S2 is completed, the loading module applies excitation to the medium to generate shear waves propagating in at least two directions in the X-Z plane inside or on the surface of the medium; S302: the signal acquisition module acquires wave front information of the shear waves; S303: extracting two-point motion information on the medium surface from the wave front information; S304: checking the motion information measured at each excitation frequency of the loading module to determine whether the motion information measured at all excitation frequencies of the loading module is reliable; S305: recording parameters of the excitation frequency, amplitude, period, and position corresponding to the reliable motion information.

16. The method of measuring the mechanical properties of a material of claim 15, wherein, The motion information in the step S303 includes displacement, velocity, and acceleration of a mass point in the medium changing with time.

17. The method of measuring the mechanical properties of a material of claim 15, wherein, The step S304 of checking the motion information measured at each excitation frequency of the loading module specifically includes checking whether a signal-to-noise ratio level meets a requirement and whether a signal attenuation level meets a requirement, if both the signal-to-noise ratio level and the signal attenuation level meet the requirements, the motion information is reliable; if one or both of the signal-to-noise ratio level and the signal attenuation level do not meet the requirements, the motion information is unreliable, then adjusting the amplitude, period, position, or / and position of the loading module at the corresponding excitation frequency, and then repeating the steps S301 to S304.

18. The method of measuring the mechanical properties of a material of claim 17, wherein, The signal-to-noise ratio is defined as follows: 100 points with the largest wavefront amplitude are selected, and the average value of the amplitudes is taken as the available signal; the voltage of the signal generator of the loading module is set to 0 in the control module, and the standard deviation of the motion amplitudes of all points in the entire ROI region collected at this time is taken as the noise; the ratio of the available signal to the noise is taken as the logarithm with base 10 and multiplied by 0 as the signal-to-noise ratio; when the signal-to-noise ratio is greater than or equal to the signal-to-noise ratio threshold set by the acquisition module, the signal-to-noise ratio level meets the requirements.

19. The method of measuring the mechanical properties of a material of claim 17, wherein, The signal attenuation level is the intensity ratio of the available signal of the measurement point farthest from the excitation position in the medium to be tested to the available signal at the excitation position, which is taken as the signal attenuation level; when the signal attenuation level is less than the signal attenuation threshold, the signal attenuation level is too strong and does not meet the requirements.

20. The method of measuring the mechanical properties of a material of claim 17, wherein, The step S4 of using the wavefront information to invert the mechanical properties of the material specifically includes the following sub-steps: S401: wavefront information analysis: under the premise that the motion information is reliable, the motion information of the particles in two different directions is extracted by selecting two different directions and extracting the motion information of the particles in the two directions with time, and the dispersion curve of the motion information is obtained from the motion information; S402: determining whether the medium is an elastic medium or a viscous medium; S405: if the medium is determined to be an elastic medium, the mechanical properties or stress distribution of the medium in different directions are inverted from the motion information and saved in the control module; S406: if the medium is determined to be a viscous medium, the dispersion curve in step S401 is directly analyzed, the viscous parameters of the medium are measured by a fitting method according to the surface wave dispersion relationship of the viscoelastic material constitutive, and the viscous parameters are saved in the control module.

21. The method of measuring the mechanical properties of a material of claim 20, wherein, The determination of whether the medium is an elastic medium or a viscous medium in step S402 is made by selecting a specific index to measure the degree of viscoelastic dispersion of the medium.

22. The method of measuring the mechanical properties of a material of claim 21, wherein, The specific index is the ratio of the phase velocity of the shear wave at a high excitation frequency to the phase velocity of the shear wave at a low excitation frequency, and the medium is determined to be an elastic medium or a viscous medium by comparing the ratio of the phase velocities with a viscoelastic threshold; if the ratio of the phase velocities is greater than the viscoelastic threshold, the medium is a viscous medium; if the ratio of the phase velocities is less than or equal to the viscoelastic threshold, the medium is an elastic medium.

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