Thrombolysis evaluation method, device and system

Abstract

The invention relates to the field of data processing, in particular to a thrombus dissolution evaluation method, device and system. The thrombus dissolution evaluation method comprises the following steps: controlling an impedance analyzer to output excitation voltage to a vibration execution module in a frequency sweep mode; obtaining a frequency response diagram after the impedance analyzer outputs the excitation voltage; determining the optimal resonant frequency a of the vibration execution module in the blood according to the frequency response diagram; determining a conductivity value corresponding to each frequency according to the frequency response diagram; determining a comprehensive evaluation index of conductance response offset according to the optimal resonant frequency a and the conductance value corresponding to each frequency; and determining the blood concentration according to the comprehensive evaluation index of the conductance response offset so as to evaluate thrombolysis. The problem that the thrombus dissolution condition in the treatment process cannot be evaluated in time is solved.

Description

Technical Field

[0001] The present invention relates to the field of data processing, and in particular to a method, device and system for evaluating thrombus dissolution. Background Art

[0002] With the rapid development of population aging, stroke has become one of the most important causes of death in my country, most of which are ischemic stroke. Ischemic stroke is caused by the formation of blood clots in blood vessels, which leads to reduced or interrupted blood supply to the brain, causing brain tissue damage, language disorders, limb movement disorders and even life-threatening.

[0003] Depending on the emergency time window, the selected treatment options are different, for example, drug therapy, surgical treatment. Currently, there are many ways to judge the dissolution of thrombus, such as nuclear magnetic resonance imaging (NMRI), computed tomography (CT), ultrasound detection, hemoelastography (TEG) and electrochemical impedance spectroscopy (EIS).

[0004] These methods generally test patients before and after treatment. The main purpose is to detect whether blood clots exist. The detection time is relatively long, and it is difficult to evaluate the thrombus dissolution during treatment. Doctors cannot adjust clinical decisions in time during treatment, and there is a problem of being unable to evaluate the thrombus dissolution during treatment in a timely manner. Summary of the invention

[0005] Based on this, it is necessary to provide a thrombus dissolution evaluation method, device and system to address the above-mentioned problems.

[0006] The embodiment of the present invention is implemented as follows: a method for evaluating thrombus dissolution, the method for evaluating thrombus dissolution comprising:

[0007] S101, controlling the impedance analyzer to output an excitation voltage to the vibration execution module using a frequency sweep mode;

[0008] S102, obtaining a frequency response diagram after the impedance analyzer outputs an excitation voltage;

[0009] S103, determining the optimal resonance frequency a of the vibration execution module in the blood according to the frequency response diagram;

[0010] S104, determining the conductance value corresponding to each frequency according to the frequency response diagram;

[0011] S105, determining a comprehensive evaluation index of the conductivity response deviation according to the optimal resonance frequency a and the conductivity value corresponding to each frequency;

[0012] S106, determining the blood concentration based on the comprehensive evaluation index of the conductivity response deviation and then evaluating the thrombus dissolution.

[0013] In one embodiment, the present invention provides a thrombus lysis evaluation device, the thrombus lysis evaluation device comprising:

[0014] A control output module is used to control the impedance analyzer to output an excitation voltage to the vibration execution module using a sweep frequency mode;

[0015] The frequency response acquisition module is used to obtain the frequency response diagram after the impedance analyzer outputs the excitation voltage;

[0016] A resonance module is determined, which is used to determine the optimal resonance frequency a of the vibration execution module in the blood according to the frequency response diagram;

[0017] A conductance determination module is used to determine the conductance value corresponding to each frequency according to the frequency response diagram;

[0018] An index determination module is used to determine a comprehensive evaluation index of the conductivity response deviation according to the optimal resonance frequency a and the conductivity value corresponding to each frequency;

[0019] The thrombus evaluation module is used to determine the blood concentration based on the comprehensive evaluation index of the conductivity response deviation and then evaluate the thrombus dissolution.

[0020] In one embodiment, the present invention provides a thrombus dissolution evaluation system, the thrombus dissolution evaluation system comprising: a vibration execution module, a signal output module and a control module;

[0021] The positive electrode of the vibration execution module is connected to the voltage output terminal of the signal output module, the negative electrode is connected to the voltage input terminal of the signal output module, and the detection end is immersed in the blood container to generate vibration;

[0022] The data communication terminal of the signal output module is connected to the data communication terminal of the control module, and is used to provide power to the vibration execution module so that the vibration execution module generates vibration and exchanges data with the control module;

[0023] The control module is used to execute the steps of the above-mentioned thrombus dissolution evaluation method.

[0024] A thrombus dissolution evaluation method provided by an embodiment of the present invention controls an impedance analyzer to output an excitation voltage to a vibration execution module using a sweep frequency mode; obtains a frequency response diagram after the impedance analyzer outputs the excitation voltage; determines the best resonant frequency a of the vibration execution module in the blood according to the frequency response diagram; determines the conductance value corresponding to each frequency according to the frequency response diagram; determines a comprehensive evaluation index of the conductance response deviation according to the best resonant frequency a and the conductance value corresponding to each frequency; determines the blood concentration according to the comprehensive evaluation index of the conductance response deviation and then evaluates the thrombus dissolution. The best resonant frequency a of the vibration execution module in the blood and the conductance value corresponding to each frequency can be obtained by the impedance analyzer in the process of outputting the excitation voltage to the vibration execution module using the sweep frequency mode, which is time-effective and can be obtained quickly, so the blood concentration can be determined in time and then the thrombus dissolution can be evaluated, solving the problem of not being able to timely evaluate the thrombus dissolution during the treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A flowchart of a method for evaluating thrombolysis in one embodiment;

[0026] Figure 2 It is a schematic diagram of the frequency response diagram of the impedance analyzer;

[0027] Figure 3 A model diagram of an improved electromechanical coupling model for a vibration execution module;

[0028] Figure 4 The equivalent schematic diagram of the improved electromechanical coupling model of the vibration execution module;

[0029] Figure 5 This is the relationship diagram between blood concentration and resonant frequency;

[0030] Figure 6 This is a graph showing the relationship between blood concentration and conductivity value;

[0031] Figure 7 is a structural block diagram of a thrombus dissolution evaluation device in one embodiment;

[0032] Figure 8 A structural diagram of a thrombolysis evaluation system in one embodiment;

[0033] Fig. 9 A structural diagram of a thrombolysis evaluation system in one embodiment;

[0034] Fig.10 FIG. 4 is a block diagram of the internal structure of a control module in an embodiment.

[0035] In the attached drawings: 1. blood container; 2. vibration execution module; 21. actuator; 22. piezoelectric sheet; 3. fixing frame; 4. signal output module; 5. control module. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] It is understood that the terms "first", "second", etc. used in the present invention may be used herein to describe various elements, but unless otherwise specified, these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, a first xx script may be referred to as a second xx script, and similarly, a second xx script may be referred to as a first xx script without departing from the scope of the present invention.

[0038] like Figure 1 As shown, in one embodiment, a method for evaluating thrombus dissolution is provided, which may specifically include the following steps:

[0039] S101, controlling the impedance analyzer to output an excitation voltage to the vibration execution module using a frequency sweep mode;

[0040] S102, obtaining a frequency response diagram after the impedance analyzer outputs an excitation voltage;

[0041] S103, determining the optimal resonance frequency a of the vibration execution module in the blood according to the frequency response diagram;

[0042] S104, determining the conductance value corresponding to each frequency according to the frequency response diagram;

[0043] S105, determining a comprehensive evaluation index of the conductivity response deviation according to the optimal resonance frequency a and the conductivity value corresponding to each frequency;

[0044] S106, determining the blood concentration based on the comprehensive evaluation index of the conductivity response deviation and then evaluating the thrombus dissolution.

[0045] In this embodiment, the frequency sweep mode is a common function of the impedance analyzer, which refers to automatically and continuously changing the frequency of the output signal at a certain step or speed within a preset frequency range. The output signal here is the excitation voltage. The preset frequency range can be 0-20kHz.

[0046] In this embodiment, this method is applied to the control module, and the impedance analyzer can directly output the frequency response diagram without being generated by a computer device. The impedance analyzer here can be replaced with other signal output devices with a sweep frequency mode. If replaced with other signal output devices, the control module can obtain the output data and return data of the signal output device, and generate a frequency response diagram according to the output data and return data of the signal output device.

[0047] In this embodiment, there are many types of frequency response diagrams. The frequency response diagram used here is a frequency response diagram of frequency and conductance, such as Figure 2 As shown in the black solid curve in the middle, the horizontal axis is frequency and the left vertical axis is conductance.

[0048] In this embodiment, the frequency response diagram includes a variety of data, such as frequency and conductance values ​​at various frequencies, which are data that do not need to be calculated.

[0049] In this embodiment, for the optimal resonant frequency a of the vibration execution module in the blood, there are multiple resonant frequencies in the frequency response diagram, and the optimal resonant frequency a is only one of the resonant frequencies. Of course, other resonant frequencies can also be used, but the sensitivity of other resonant frequencies to changes in blood concentration is not as good as the sensitivity of the optimal resonant frequency a to changes in blood concentration. The blood here can be blood that has not been separated from the body. For example, during the surgical treatment of the patient, the vibration execution module can be a drug delivery device that enters the blood vessel, a mechanical thrombus removal device, etc.; the blood can also be isolated blood, and the isolated blood includes blood extracted from the human body during the surgical treatment. In this case, the vibration execution device can be an independent vibration execution device.

[0050] In this embodiment, the comprehensive evaluation index of the conductivity response deviation has a corresponding relationship with the blood concentration, and the corresponding relationship is obtained through the experimental data of the experimental model, so the blood concentration can be known by knowing the comprehensive evaluation index of the conductivity response deviation. From the perspective of hematology and biochemistry, pig blood is similar to human blood, especially the aggregation process of red blood cells is also close to human blood. Therefore, pig blood is suitable for thrombosis, so different concentrations of pig red blood cells are prepared to establish an experimental model to simulate the changes in blood concentration during thrombus dissolution, which not only avoids the ethical issues of using human blood, but also can provide an experimental model close to human conditions for research.

[0051] In this embodiment, blood is mainly composed of plasma and red blood cells, and red blood cells are the main components of thrombus. Therefore, when the thrombus is not dissolved and is a solid block, it can be simply understood that there are plasma and thrombus in the blood vessel. Of course, it is difficult for the blood vessel to only have plasma and thrombus. The plasma also contains some red blood cells, but due to the composition of the thrombus, the blood concentration at this time must be lower than the normal blood concentration. As the thrombus dissolves, it is equivalent to the solute dissolving in the solution. At this time, the concentration of plasma as a solution will increase, and the comprehensive evaluation index of the conductivity response offset will increase. If the comprehensive evaluation index of the conductivity response offset is larger, it means that the thrombus is dissolved. When the thrombus is dissolved, the blood concentration will not change. The comprehensive evaluation index of the conductivity response offset will not change when it reaches the maximum. Therefore, the change of the comprehensive evaluation index of the conductivity response offset can be used to evaluate the thrombus dissolution. As the thrombus dissolves, the blood concentration increases. When it rises to the maximum and does not change for a short time, it means that the thrombus is basically dissolved. After that, it decreases, indicating that the blood vessel is unblocked and normal blood supply is restored. According to the bidirectional electromechanical conversion effect of piezoelectric materials, this increase in concentration can be reflected by measuring the piezoelectric admittance signal. In order to reflect the change in blood concentration more intuitively, the comprehensive evaluation index of conductivity response deviation is used to evaluate this change.

[0052] A thrombus dissolution evaluation method provided by an embodiment of the present invention controls an impedance analyzer to output an excitation voltage to a vibration execution module using a sweep frequency mode; obtains a frequency response diagram after the impedance analyzer outputs the excitation voltage; determines the best resonant frequency a of the vibration execution module in the blood according to the frequency response diagram; determines the conductance value corresponding to each frequency according to the frequency response diagram; determines a comprehensive evaluation index of the conductance response deviation according to the best resonant frequency a and the conductance value corresponding to each frequency; determines the blood concentration according to the comprehensive evaluation index of the conductance response deviation and then evaluates the thrombus dissolution. The best resonant frequency a of the vibration execution module in the blood and the conductance value corresponding to each frequency can be obtained by the impedance analyzer in the process of outputting the excitation voltage to the vibration execution module using the sweep frequency mode, which is time-effective and can be obtained quickly, so the blood concentration can be determined in time and then the thrombus dissolution can be evaluated, solving the problem of not being able to timely evaluate the thrombus dissolution during the treatment process.

[0053] In one embodiment, determining the optimal resonant frequency a of the vibration execution module in the blood according to the frequency response diagram includes:

[0054] Determine the change curve of frequency and conductance value in the frequency response diagram;

[0055] Smoothing the change curve to obtain a first curve;

[0056] Obtaining a peak in the first curve and determining a frequency corresponding to the peak, which is recorded as a resonant frequency of the vibration execution module in the blood;

[0057] The optimal resonance frequency a of the vibration execution module in the blood is determined among the resonance frequencies of the vibration execution module in the blood.

[0058] In this embodiment, the change curve is as follows: Figure 2 As shown, because in the resonant state, the inductive reactance and capacitive reactance of the circuit are equal, the circuit appears to be a pure resistor to the outside, so that the energy is concentrated at a specific frequency to form a peak. Therefore, the frequency corresponding to the peak is the resonant frequency.

[0059] In this embodiment, the smoothing process can be implemented by using algorithms such as a Gaussian weighted moving average filter algorithm, a sliding average filter algorithm, a convolution sliding average filter algorithm, a filter filter algorithm, and a Kalman filter algorithm.

[0060] In this embodiment, different resonance frequencies have different sensitivities to changes in blood concentration (or thrombus dissolution), and the resonance frequency with the highest sensitivity is determined as the optimal resonance frequency a of the vibration execution module in the blood.

[0061] In one embodiment, determining the optimal resonance frequency a of the vibration execution module in the blood from the resonance frequency of the vibration execution module in the blood comprises:

[0062] Performing baseline processing on the change curve to obtain a second curve;

[0063] For each resonance frequency of the vibration execution module in the blood, determining a relational value of the resonance frequency in the first curve and a relational value in the second curve;

[0064] Subtracting the two relationship values ​​​​gets the deviation value of the resonant frequency;

[0065] Sort all the resonant frequencies according to their deviation values ​​from large to small;

[0066] Select a preset number of deviation values ​​that are ranked first;

[0067] Select the deviation value P with the highest frequency among the selected deviation values;

[0068] The resonance frequency corresponding to the deviation value P is determined as the optimal resonance frequency a of the vibration execution module in the blood.

[0069] In this embodiment, the baseline processing of the change curve means treating the values ​​corresponding to the waves of the change curve as discrete values ​​and eliminating them to obtain the baseline of the change curve, and then smoothing the baseline. Therefore, the second curve is the baseline after smoothing. There is also a simpler processing method, such as Figure 2As shown in the figure, there is a smooth upward curve before the wave from the initial frequency to the first resonant frequency. The straight line obtained by linear fitting of this curve is used as the baseline of the change curve. Of course, the baseline of the change curve can also be directly determined through Origin.

[0070] In this embodiment, if Figure 2 As shown, the horizontal axis is frequency and the left vertical axis is conductance, so the relationship value of the resonant frequency in the first curve refers to the conductance value corresponding to the resonant frequency in the first curve. The relationship value of the resonant frequency in the second curve is similar.

[0071] In this embodiment, the preset number may be 3.

[0072] In this embodiment, in order to explore the sensitivity of the comprehensive evaluation index of the conductivity response deviation to the change of red blood cell concentration under different resonance modes, the one-variable-at-a-time approach (OAT) is used to perform sensitivity analysis on the experimental data of the experimental model. This method is to calculate the gradient or derivative of each set of data relative to the change of red blood cell concentration. If the absolute value of the derivative of a set of data is large, it means that this set of data is more sensitive to the change of red blood cell concentration. The experimental data show that with the increase of the resonant frequency, the sensitivity of the comprehensive evaluation index of the conductivity response deviation relative to the change of red blood cell concentration is gradually increasing. It means that for changes in blood density and viscosity, higher vibration frequency detection is more sensitive. This is because as the frequency increases, the wavelength of excitation will also decrease, and smaller changes can be identified. Therefore, the resonant frequency corresponding to the deviation value P is determined as the optimal resonant frequency a of the vibration execution module in the blood.

[0073] In one embodiment, the comprehensive evaluation index of the conductivity response deviation is determined according to the optimal resonant frequency a and the conductivity value corresponding to each frequency, including:

[0074] Depend on The root mean square difference RMSD of the conductivity values ​​is obtained;

[0075] The resonance frequency offset Δf of the optimal resonance frequency a is obtained from ab;

[0076] Determine a weight coefficient β of the resonance frequency offset of the optimal resonance frequency a and a weight coefficient α of the root mean square difference of the conductance value;

[0077] The comprehensive evaluation index of conductivity response deviation is obtained by α×RMSD+β×Δf;

[0078] Among them, G1(ωj) is the conductivity value of ωj in blood, G0(ωj) is the conductivity value of ωj in pure plasma, ω jis the jth angular frequency, N is the number of frequencies used in the sweep frequency mode of the impedance analyzer, j is the serial number of the frequencies used in the sweep frequency mode of the impedance analyzer, a is the optimal resonant frequency of the vibration execution module in blood, and b is the optimal resonant frequency of the vibration execution module in pure plasma.

[0079] In this embodiment, a is the optimal resonant frequency of the vibration execution module in blood, so a is the frequency corresponding to an angular frequency in G1(ωj). b is the optimal resonant frequency of the vibration execution module in pure plasma, so b is the frequency corresponding to an angular frequency in G0(ωj).

[0080] In this embodiment, since ω j =2πf j , so even if Figure 2 is the frequency response diagram of frequency and conductance, and it is also easy to derive the frequency response diagram of angular frequency and conductance. Figure 2 is G0(fj), then G0(ωj) is G0(2πfj). The root mean square deviation RMSD used here is the conductance value, so whether the horizontal axis is angular frequency or frequency does not affect the determination of the conductance value.

[0081] In this embodiment, in the experimental model, the vibration execution module includes a piezoelectric sheet and an actuator. When the vibration execution module vibrates back and forth in a bending mode after an alternating voltage is applied, this causes the surrounding liquid to generate a planar flow. The blood is approximately regarded as a Newtonian fluid, the length direction of the actuator is regarded as the x direction, and the thickness direction of the actuator is regarded as the y direction. According to the Navier-Stokes equation, the attenuation of the laminar motion in the y direction is expressed by an equation as follows:

[0082]

[0083] Among them, v x is the laminar velocity of the fluid, t is the time, η is the viscosity of the liquid, v0 is the complex amplitude of the vibration actuator velocity, ω is the angular frequency of the vibration actuator oscillation, i is the unit of the imaginary part of the complex number, x is the coordinate in the x direction, and y is the coordinate in the y direction. The solution to the equation is

[0084]

[0085] Applying appropriate boundary conditions at y→∞ and y=0, the shear stress at the wall of the vibration actuator module can be obtained:

[0086]

[0087] If the effect of thickness and roughness of the vibration actuator is ignored, the viscous drag along the x-direction is:

[0088]

[0089] Where ρ is the blood density and S is the surface area of ​​the vibrating actuator that is immersed in the solution. The mechanical impedance generated by the fluid dynamic load on the vibrating actuator is defined as

[0090]

[0091] The above formula contains a real part and an imaginary part, where the real part is the mechanical impedance related to the liquid damping effect, and the imaginary part is the mechanical impedance related to the liquid inertia effect. Therefore, when the blood vibrates, the interaction between the vibration actuator and the blood hydrodynamic force can be expressed by the additional damping Vc and the additional mass Vm:

[0092]

[0093] When the vibration execution module is immersed in blood of different concentrations for vibration testing, the improved electromechanical coupling model of the vibration execution module is as follows Figure 3 shown. Figure 3 Where m is the mass of the vibration actuator module, k A is the equivalent stiffness of the vibration actuator module, c is the equivalent damping of the vibration actuator module, Vc is the additional damping of the blood, and Vm is the additional mass of the blood. Considering that the longitudinal dimension and thickness dimension of the PZT piezoelectric sheet are quite different, the vibration in the thickness direction can be ignored. The PZT piezoelectric sheet is an energized component connected to the output end and the output end of the impedance analyzer in the vibration actuator module. Therefore, the PZT piezoelectric sheet is regarded as a long and narrow rod that vibrates longitudinally. The PZT piezoelectric sheet is fixed on the actuator to form a vibration actuator module. The vibration actuator module is a mechanical vibration system with single-degree-of-freedom longitudinal vibration. The stiffness and damping of the actuator are consistent with the electromechanical coupling characteristics of PZT. The motion of the PZT piezoelectric sheet in the x direction is expressed by the wave equation as follows:

[0094]

[0095] Among them, u A (x, t) is the displacement of the PZT piezoelectric piece along the x direction; ρ A is the density of the PZT piezoelectric sheet; is the composite Young's modulus of the PZT piezoelectric film under electric field. Solve the above equation and replace the displacement u A (x, t) is decomposed into the spatial domain and the time domain, and we get

[0096]

[0097] Where k is the wave number. One of the known boundary conditions is x = 0, u A (x, t) = 0, so B = 0. Another boundary condition is obtained by the mechanical impedance method. Considering the influence of the solution in the dynamic system, the mechanical impedance of the actuator is expressed as

[0098]

[0099] Where c is the equivalent damping of the vibration execution module, m is the mass of the vibration execution module, k S is the static stiffness of the actuator, and ω is the angular frequency of oscillation of the vibration actuator module.

[0100] The mechanical impedance of the PZT piezoelectric sheet is introduced and defined as the ratio of the equivalent excitation force to the velocity response when the PZT piezoelectric sheet freely expands and contracts under an alternating electric field. The mechanical impedance can be expressed as:

[0101]

[0102] in, is the complex static stiffness of the PZT piezoelectric piece, k is the wave number, l A is the length of the PZT piezoelectric piece. Therefore, substitute the constant A into u A (x, t), and thus the strain and stress of the PZT piezoelectric sheet are obtained, and the electric displacement is obtained as

[0103]

[0104] in, is the piezoelectric coefficient of force, is the piezoelectric strain constant.

[0105] For simple harmonic excitation, the instantaneous current is defined as:

[0106]

[0107] According to the definition of electric field intensity, the voltage expression is: And the expression of admittance is Y = I / V, so the expression of the electrical admittance of the PZT piezoelectric sheet is

[0108]

[0109] Among them, w A is the width of the PZT piezoelectric film, h A is the thickness of the PZT piezoelectric film.

[0110] In most practical applications, the required frequency range is much lower than the resonant frequency of the PZT piezoelectric piece, so tan(klA) / klA≈1, which simplifies to

[0111]

[0112] For the selected PZT piezoelectric piece, its own mechanical impedance value Z A Can be regarded as a constant, the mechanical impedance Z of the structure connected to it SThe PZT piezoelectric sheet has a unique electrical conductance value Y. When external conditions change, its structural mechanical impedance Z S will change, so measuring the change of the coupled system admittance value Y can reflect the changes in the outside world. When the admittance is maximum (i.e. the current is maximum), |Y|→∞, the denominator of the admittance function is zero, and the coupled system resonates. According to the impedance characteristics of the resonant circuit, the circuit phase response is zero at this time, i.e. the mechanical impedance Z S and Z A The imaginary parts of are opposite to each other, then:

[0113]

[0114] Solving the above equation, we can get the resonant frequency of the coupled system: for

[0115]

[0116] in, is the resonant frequency of the vibration actuator in the blood, is the complex static stiffness of the PZT piezoelectric piece, k S is the static stiffness of the actuator, S is the area of ​​the vibration actuator module immersed in the blood, m is the mass of the vibration actuator module, η is the liquid viscosity, that is, the blood viscosity, and ρ is the blood density.

[0117] The product of blood viscosity and blood density is blood concentration, that is, ηρ is blood concentration. This is obtained by combining the Navier-Storrs equation and the piezoelectric admittance relationship.

[0118] From the above formula, it can be seen that the system resonant frequency of the vibration actuator module is related to the complex static stiffness of the piezoelectric material, the static stiffness of the actuator, the mass, the area immersed in the blood, and the blood concentration (the product of viscosity η and density ρ). Among them, the complex static stiffness of the piezoelectric material, the static stiffness of the actuator, and the mass are constants, that is, the system resonant frequency of the vibration actuator module changes with the change of blood concentration.

[0119] At present, the BVD equivalent circuit is widely used to simulate the electrical characteristics of quartz crystal sensors. The BVD circuit is called a lumped element model circuit, which consists of a static branch (capacitor C1, resistor R1, inductor L1) and a static capacitor C0 in parallel. Combined with actual application, the BVD circuit is improved to describe the electrical characteristics of the piezoelectric actuator coupling system when it vibrates in a solution, such as Figure 4As shown, capacitor C1, resistor R1 and inductor L1 are the equivalent circuit of the vibration execution module, and resistor R2 and inductor L2 are the equivalent circuit of the blood load. When the vibration execution module vibrates in the blood, additional damping and attached mass are generated due to the parasitic effect of the vibration execution module. According to the electromechanical equivalent principle, the mass is equivalent to the inductance, the damping is equivalent to the resistance, and the stiffness is equivalent to the capacitance. This solution parasitic effect increases the resistance R2 and inductance L2 of the dynamic branch. According to the characteristics of the series circuit, the dynamic branch can be simplified to R3 = R1 + R2, L3 = L1 + L2, and the admittance expression of the equivalent circuit is obtained as follows:

[0120]

[0121] Where C3 is equal to C1, the resonance condition at the maximum piezoelectric admittance is:

[0122]

[0123] The real part signal of the piezoelectric admittance of the conductance G is more sensitive to changes in external conditions, that is:

[0124]

[0125] Since R3=R1+R2, L3=L1+L2, R2 and L2 are related to blood concentration, so R3∝ηρ, L3∝ηρ.

[0126] In summary, the solution load of blood increases the attached mass and additional damping of the electromechanical coupling system, and also increases the inductance and resistance of the equivalent circuit, which changes the resonant frequency and conductance of the electromechanical coupling system. According to the above four formulas, it can be seen that the change in blood concentration is directly related to the resonant frequency and conductance. Therefore, it is scientific and reasonable to select these two parameters as effective evaluation parameters. As the blood concentration increases, the resonance frequencies and conductance peaks of the vibration execution module will gradually decrease. Figure 5 and Figure 6 shown.

[0127] In order to quantitatively represent the changes in blood concentration and thus better evaluate the effect of thrombolysis, it is necessary to consider the difference between the conductivity response curves of different blood concentrations and the conductivity response curves of pure plasma, and to combine the offset of the resonant frequency. Therefore, based on the root mean square difference of the resonant frequency offset and the conductivity value, a comprehensive evaluation index of the conductivity response offset is used to quantitatively represent the blood concentration.

[0128] In one embodiment, the weight coefficient β of the resonance frequency offset of the optimal resonance frequency a and the weight coefficient α of the root mean square difference of the conductance value are determined, including:

[0129] Determine in the preset frequency table the preset frequency range within which the optimal resonant frequency a falls;

[0130] Determine the weight coefficient of the resonance frequency offset corresponding to the preset frequency range within which the optimal resonance frequency a falls as the weight coefficient β of the resonance frequency offset of the optimal resonance frequency a;

[0131] The weight coefficient α of the root mean square difference of the conductance values ​​is obtained from 1-β.

[0132] In this embodiment, α and β are weight coefficients, so α+β equals 1, that is, as long as one value is known, the other value can be known.

[0133] In this embodiment, based on the experimental data of the experimental model, the data of the resonant frequency offset and the root mean square deviation of the same resonant frequency are preprocessed, and then the respective weight coefficients are calculated respectively in combination with the hierarchical analysis method (AHP) and the principal component analysis method (PCA), and the sum and average thereof are taken to obtain the final weight coefficient. The same operation is performed on multiple resonant frequencies to obtain the weight coefficients α and β corresponding to the multiple resonant frequencies. In essence, only one needs to be calculated. A preset frequency table is formed based on multiple resonant frequencies. The preset frequency range can be ±5% of each resonant frequency.

[0134] In this embodiment, if the optimal resonant frequency a does not fall within any preset range in the preset frequency table, the weight coefficient α can be determined to be 0.17 and the weight coefficient β can be determined to be 0.83. This is the average value of the weight coefficients obtained based on the experimental data of the experimental model.

[0135] In one embodiment, determining the blood concentration based on the comprehensive evaluation index of the conductivity response deviation and then evaluating the thrombus dissolution includes:

[0136] Subtracting the comprehensive evaluation index of the conductivity response deviation from the comprehensive evaluation index of the reference condition to obtain a comparison value;

[0137] Determine the index interval into which the comparison value falls in the preset comprehensive evaluation index comparison table;

[0138] Determine the blood concentration corresponding to the index interval as the current blood concentration;

[0139] Thrombolysis is assessed based on current changes in blood concentrations.

[0140] In this embodiment, the reference condition refers to the conductivity response deviation of the vibration execution module in pure plasma. This data is obtained from experimental data. The comprehensive evaluation index of the reference condition is generally 0.

[0141] In this embodiment, the preset comprehensive rating index comparison table is obtained from the experimental data of the experimental model. Each blood concentration in the preset comprehensive evaluation comparison table has a corresponding index interval, so the blood concentration corresponding to the index interval in which the comparison value falls is the current blood concentration.

[0142] In this embodiment, thrombus dissolution is evaluated according to the current change of blood concentration, including that although it is of course difficult for a blood vessel to consist of only plasma and thrombus, and plasma also contains some red blood cells, the blood concentration at this time must be much lower than the normal blood concentration due to the composition of thrombus. The blood concentration at this time corresponds to a comprehensive evaluation index. As the thrombus dissolves, the blood concentration rises, and the comprehensive evaluation index also gradually rises. When the thrombus is completely dissolved, the blood concentration no longer changes, and the comprehensive evaluation index of the conductivity response offset reaches the maximum and no longer changes. Therefore, evaluating thrombus dissolution according to the current change of blood concentration is essentially evaluating thrombus dissolution according to the change of the comprehensive evaluation index of the conductivity response offset.

[0143] like Figure 7 As shown, in one embodiment, a thrombus dissolution evaluation device is provided, which may specifically include:

[0144] A control output module is used to control the impedance analyzer to output an excitation voltage to the vibration execution module using a frequency sweep mode;

[0145] The frequency response acquisition module is used to obtain the frequency response diagram after the impedance analyzer outputs the excitation voltage;

[0146] A resonance module is determined, which is used to determine the optimal resonance frequency a of the vibration execution module in the blood according to the frequency response diagram;

[0147] A conductance determination module is used to determine the conductance value corresponding to each frequency according to the frequency response diagram;

[0148] An index determination module is used to determine a comprehensive evaluation index of the conductivity response deviation according to the optimal resonance frequency a and the conductivity value corresponding to each frequency;

[0149] The thrombus evaluation module is used to determine the blood concentration based on the comprehensive evaluation index of the conductivity response deviation and then evaluate the thrombus dissolution.

[0150] In this embodiment, each module of the thrombus dissolution evaluation device is a modularization of the method part of the present invention. For the specific explanation of each module, please refer to the corresponding content of the method part of the present invention, and the embodiment of the present invention will not be repeated here.

[0151] like Figure 8 As shown, in one embodiment, a thrombus dissolution evaluation system is provided, which may specifically include: a vibration execution module 2, a signal output module 4 and a control module 5;

[0152] The positive electrode of the vibration execution module 2 is connected to the voltage output terminal of the signal output module 4, the negative electrode is connected to the voltage input terminal of the signal output module 4, and the detection end is immersed in the blood container 1 to generate vibration;

[0153] The data communication end of the signal output module 4 is connected to the data communication end of the control module 5, and is used to provide power to the vibration execution module 2 so that the vibration execution module 2 generates vibration and exchanges data with the control module 5;

[0154] The control module 5 is used to execute the steps of the above-mentioned thrombus dissolution evaluation method.

[0155] In this embodiment, for example, during a thrombus removal operation, the vibration execution module 2 can be a thrombus removal device, and there is a vibration actuator 21 for cerebral thrombus removal and a thrombus removal device, which can be used to generate vibration to dissolve and destroy the thrombus. For example, during an operation or drug treatment, the vibration execution module 2 can be a device with a vibration function, but not necessarily a thrombus removal function.

[0156] In this embodiment, the signal output module 4 may be a device that only outputs and receives signals. If so, the control module 5 needs to first obtain the output data and return data of the signal output module 4 in the steps of executing the above-mentioned thrombus dissolution evaluation method, and generate a frequency response diagram according to the output data and return data of the signal output module 4. Of course, the signal output module 4 may be a signal output device with a data processing function. If so, the control module 5 can directly obtain the frequency response diagram.

[0157] The thrombus dissolution evaluation system provided by the embodiment of the present invention controls the impedance analyzer to output the excitation voltage to the vibration execution module 2 using the sweep frequency mode; obtains the frequency response diagram after the impedance analyzer outputs the excitation voltage; determines the best resonant frequency a of the vibration execution module 2 in the blood according to the frequency response diagram; determines the conductance value corresponding to each frequency according to the frequency response diagram; determines the comprehensive evaluation index of the conductance response deviation according to the best resonant frequency a and the conductance value corresponding to each frequency; determines the blood concentration according to the comprehensive evaluation index of the conductance response deviation and then evaluates the thrombus dissolution. The best resonant frequency a of the vibration execution module 2 in the blood and the conductance value corresponding to each frequency can be obtained by the impedance analyzer in the process of outputting the excitation voltage to the vibration execution module 2 using the sweep frequency mode, which is time-effective and can be obtained quickly, so the blood concentration can be determined in time and then the thrombus dissolution can be evaluated, which solves the problem that the thrombus dissolution during the treatment process cannot be evaluated in time.

[0158] like Fig. 9As shown, in one embodiment, the vibration execution module 2 includes a piezoelectric sheet 22 and an actuator 21;

[0159] The positive electrode of the piezoelectric sheet 22 is connected to the voltage output terminal of the signal output module 4, and the negative electrode is connected to the voltage input terminal of the signal output module 4. The piezoelectric sheet 22 is closely attached to the front end of the actuator 21 to make the actuator 21 vibrate.

[0160] The end of the actuator 21 is immersed in the blood to generate vibration.

[0161] In this embodiment, the piezoelectric sheet 22 may be a PZT piezoelectric sheet, for example, a PZT5-H piezoelectric sheet.

[0162] In this embodiment, the actuator 21 may be a stainless steel beam, which is a homogeneous beam with a non-uniform cross-section, a triangular end, and a front end fixed to the fixing frame 3 .

[0163] In this embodiment, when the piezoelectric sheet 22 starts to be energized, the piezoelectric sheet 22 will vibrate due to the piezoelectric effect and motor coupling consumption. The piezoelectric sheet 22 is closely attached to the front end of the actuator 21, so it will drive the actuator 21 to vibrate together.

[0164] In one embodiment, the signal output module 4 is an impedance analyzer.

[0165] In this embodiment, the impedance analyzer can directly output the frequency response diagram of frequency and conductance, which reduces the calculation process of the control module 5.

[0166] Fig.10 FIG. 2 shows an internal structure diagram of a control module in an embodiment. Fig.10 As shown, the control module includes a processor, a memory, a network interface, an input device and a display screen connected through a device bus. Among them, the memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the control module stores an operating device and may also store a computer program. When the computer program is executed by the processor, the processor can implement a thrombus dissolution evaluation method provided in an embodiment of the present invention. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can execute a thrombus dissolution evaluation method provided in an embodiment of the present invention. The display screen of the control module may be a liquid crystal display screen or an electronic ink display screen, and the input device of the control module may be a touch layer covering the display screen, or a button, trackball or touchpad provided on the housing of the control module, or an external keyboard, touchpad or mouse, etc.

[0167] Those skilled in the art will understand that Fig.10The structure shown in the figure is only a block diagram of a partial structure related to the scheme of the present invention, and does not constitute a limitation on the control module to which the scheme of the present invention is applied. The specific control module may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0168] In one embodiment, a thrombus dissolution evaluation device provided by an embodiment of the present invention can be implemented in the form of a computer program. The computer program can be used in Fig.10 The memory of the control module can store various program modules constituting the thrombus lysis evaluation device, for example, Figure 7 The control output module, the frequency response acquisition module, the resonance determination module, the conductivity determination module, the index determination module and the thrombus evaluation module shown in the figure. The computer program composed of each program module enables the processor to execute the steps of a thrombus dissolution evaluation method of each embodiment of the present invention described in this specification.

[0169] For example, Fig.10 The control module shown can be Figure 7 The control output module in the thrombus dissolution evaluation device shown executes step S101; the control module can execute step S102 by acquiring the frequency response module; the control module can execute step S103 by determining the resonance module; the control module can execute step S104 by determining the conductance module; the control module can execute step S105 by determining the indicator module; the control module can execute step S106 by evaluating the thrombus module.

[0170] In one embodiment, a control module is provided, the control module comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the following steps when executing the computer program:

[0171] S101, controlling the impedance analyzer to output an excitation voltage to the vibration execution module using a frequency sweep mode;

[0172] S102, obtaining a frequency response diagram after the impedance analyzer outputs an excitation voltage;

[0173] S103, determining the optimal resonance frequency a of the vibration execution module in the blood according to the frequency response diagram;

[0174] S104, determining the conductance value corresponding to each frequency according to the frequency response diagram;

[0175] S105, determining a comprehensive evaluation index of the conductance response deviation according to the optimal resonance frequency a and the conductance value corresponding to each frequency;

[0176] S106, determining the blood concentration based on the comprehensive evaluation index of the conductivity response deviation and then evaluating the thrombus dissolution.

[0177] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the processor performs the following steps:

[0178] S101, controlling the impedance analyzer to output an excitation voltage to the vibration execution module using a frequency sweep mode;

[0179] S102, obtaining a frequency response diagram after the impedance analyzer outputs an excitation voltage;

[0180] S103, determining the optimal resonance frequency a of the vibration execution module in the blood according to the frequency response diagram;

[0181] S104, determining the conductance value corresponding to each frequency according to the frequency response diagram;

[0182] S105, determining a comprehensive evaluation index of the conductance response deviation according to the optimal resonance frequency a and the conductance value corresponding to each frequency;

[0183] S106, determining the blood concentration based on the comprehensive evaluation index of the conductivity response deviation and then evaluating the thrombus dissolution.

[0184] It should be understood that, although each step in the flow chart of each embodiment of the present invention is shown in sequence according to the indication of the arrow, these steps are not necessarily performed in sequence according to the order indicated by the arrow. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be performed in other orders. Moreover, at least a portion of the steps in each embodiment may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these sub-steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0185] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present invention can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0186] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0187] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for evaluating thrombolysis, characterized in that: The thrombolysis assessment method comprises: S101, controlling the impedance analyzer to output an excitation voltage to the vibration execution module using a frequency sweep mode; S102, obtaining a frequency response diagram after the impedance analyzer outputs an excitation voltage; S103, determining the optimal resonance frequency a of the vibration execution module in the blood according to the frequency response diagram; S104, determining the conductance value corresponding to each frequency according to the frequency response diagram; S105, determining a comprehensive evaluation index of the conductance response deviation according to the optimal resonance frequency a and the conductance value corresponding to each frequency; S106, determining the blood concentration based on the comprehensive evaluation index of the conductivity response deviation and then evaluating the thrombus dissolution.

2. The method for evaluating thrombolysis according to claim 1, characterized in that: Determining the optimal resonant frequency a of the vibration execution module in the blood according to the frequency response diagram includes: Determine the change curve of frequency and conductance value in the frequency response diagram; Smoothing the change curve to obtain a first curve; Obtaining a peak in the first curve and determining a frequency corresponding to the peak, which is recorded as a resonant frequency of the vibration execution module in the blood; The optimal resonance frequency a of the vibration execution module in the blood is determined among the resonance frequencies of the vibration execution module in the blood.

3. The method for evaluating thrombolysis according to claim 2, characterized in that: The step of determining the optimal resonance frequency a of the vibration execution module in the blood from the resonance frequency of the vibration execution module in the blood comprises: Performing baseline processing on the change curve to obtain a second curve; For each resonance frequency of the vibration execution module in the blood, determining a relational value of the resonance frequency in the first curve and a relational value in the second curve; Subtracting the two relationship values ​​​​gets the deviation value of the resonant frequency; Sort all the resonant frequencies according to their deviation values ​​from large to small; Select a preset number of deviation values ​​that are ranked first; Select the deviation value P with the highest frequency among the selected deviation values; The resonance frequency corresponding to the deviation value P is determined as the optimal resonance frequency a of the vibration execution module in the blood.

4. The method for evaluating thrombolysis according to claim 1, characterized in that: The comprehensive evaluation index of the conductivity response deviation is determined according to the optimal resonance frequency a and the conductivity value corresponding to each frequency, including: Depend on The root mean square difference RMSD of the conductivity values ​​is obtained; The resonance frequency offset Δf of the optimal resonance frequency a is obtained from ab; Determine a weight coefficient β of the resonance frequency offset of the optimal resonance frequency a and a weight coefficient α of the root mean square difference of the conductance value; The comprehensive evaluation index of conductivity response deviation is obtained by α×RMSD+β×Δf; Among them, G1(ωj) is the conductivity value of ωj in blood, G0(ωj) is the conductivity value of ωj in pure plasma, ω j is the jth angular frequency, N is the number of frequencies used in the sweep frequency mode of the impedance analyzer, j is the serial number of the frequencies used in the sweep frequency mode of the impedance analyzer, a is the optimal resonant frequency of the vibration execution module in blood, and b is the optimal resonant frequency of the vibration execution module in pure plasma.

5. The method for evaluating thrombolysis according to claim 4, characterized in that: The weight coefficient β of the resonant frequency offset for determining the optimal resonant frequency a and the weight coefficient α of the root mean square difference of the conductance value include: Determine in the preset frequency table the preset frequency range within which the optimal resonant frequency a falls; Determine the weight coefficient of the resonance frequency offset corresponding to the preset frequency range within which the optimal resonance frequency a falls as the weight coefficient β of the resonance frequency offset of the optimal resonance frequency a; The weight coefficient α of the root mean square difference of the conductance values ​​is obtained from 1-β.

6. The method for evaluating thrombolysis according to claim 1, characterized in that: The method of determining the blood concentration based on the comprehensive evaluation index of the conductivity response deviation and then evaluating the thrombus dissolution includes: Subtracting the comprehensive evaluation index of the conductivity response deviation from the comprehensive evaluation index of the reference condition to obtain a comparison value; Determine the index interval into which the comparison value falls in the preset comprehensive evaluation index comparison table; Determine the blood concentration corresponding to the index interval as the current blood concentration; Thrombolysis is assessed based on current changes in blood concentrations.

7. A thrombus dissolution evaluation device, characterized in that: The thrombolysis evaluation device comprises: A control output module is used to control the impedance analyzer to output an excitation voltage to the vibration execution module using a frequency sweep mode; The frequency response acquisition module is used to obtain the frequency response diagram after the impedance analyzer outputs the excitation voltage; A resonance module is determined, which is used to determine the optimal resonance frequency a of the vibration execution module in the blood according to the frequency response diagram; A conductance determination module is used to determine the conductance value corresponding to each frequency according to the frequency response diagram; An index determination module is used to determine a comprehensive evaluation index of the conductivity response deviation according to the optimal resonance frequency a and the conductivity value corresponding to each frequency; The thrombus evaluation module is used to determine the blood concentration based on the comprehensive evaluation index of the conductivity response deviation and then evaluate the thrombus dissolution.

8. A thrombolysis evaluation system, characterized in that: The thrombus dissolution evaluation system comprises: a vibration execution module, a signal output module and a control module; The positive electrode of the vibration execution module is connected to the voltage output terminal of the signal output module, the negative electrode is connected to the voltage input terminal of the signal output module, and the detection end is immersed in the blood container to generate vibration; The data communication terminal of the signal output module is connected to the data communication terminal of the control module, and is used to provide power to the vibration execution module so that the vibration execution module generates vibration and exchanges data with the control module; The control module is used to execute the steps of the thrombolysis evaluation method according to any one of claims 1 to 6.

9. The thrombolysis evaluation system according to claim 8, characterized in that: The vibration execution module includes a piezoelectric sheet and an actuator; The positive electrode of the piezoelectric sheet is connected to the voltage output terminal of the signal output module, and the negative electrode is connected to the voltage input terminal of the signal output module. The piezoelectric sheet is closely attached to the front end of the actuator to make the actuator vibrate. The end of the actuator is immersed in the blood and is used to generate vibrations.

10. The thrombolysis evaluation system according to claim 8, characterized in that: The signal output module is an impedance analyzer.

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