A method for preoperative non-invasive judgement of plaque stability

Abstract

The application discloses a method for judging plaque stability before operation. The method reconstructs a carotid artery lesion stenosis model on the basis of collecting clinical data such as CTA and DSA of a head and neck of a patient; combines pathological data such as ultrasound, blood viscosity and blood fat to represent blood rheological property data of the patient, and constructs a multi-component and multi-phase flow model of the carotid artery of the human body; on the basis of testing the elastic properties of solid materials of stable plaques, unstable plaques and blood vessel walls, bidirectional fluid-structure coupling models containing the stable plaques and the unstable plaques are respectively constructed; numerical simulation is carried out on the above models, and the medical image examination data are compared and analyzed with the flow velocity, local cross-sectional flow and cross-sectional flow line of typical points in the two types of models to judge the stability of plaques in a lesion region of the patient. The application can provide visual changes of hemodynamic parameters of the patient for doctors by using numerical simulation, and provides a personalized medical examination scheme for carotid stenosis patients, and has great clinical significance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of carotid atherosclerotic plaque stability judgment, and in particular to a method for judging plaque stability non-invasively before operation. BACKGROUND

[0002] Atherosclerosis is an important cause of carotid artery stenosis, and intravascular plaques are divided into stable plaques and unstable plaques. Unstable plaques are prone to rupture and shedding, which can cause high mortality of stroke. Therefore, judging the stability of plaques is an important factor for patients to develop a CEA operation plan. Current research on plaque stability mainly focuses on preoperative medical imaging observation and postoperative biological tissue analysis. Preoperative medical imaging observation methods include IVUS+TCD, BB-MRI, etc., which have problems such as unclear detection site, long examination period, high examination cost, and low accuracy of judgment. Postoperative biological tissue analysis method needs to remove part of the patient's plaque for pathological typing test, which can accurately determine the stability of the plaque, but requires surgical intervention and has the problem of greater trauma. Therefore, it is urgent to develop a plaque stability evaluation method that improves the accuracy of preoperative medical examination and is non-invasive.

[0003] Numerical simulation has become one of the effective methods to assist in studying the changes of blood flow microenvironment in the human body. The granted invention patent CN109754388B discloses a method for calculating the degree of carotid artery stenosis, which provides flow analysis for the degree of carotid artery stenosis based on numerical simulation, but cannot be used for plaque stability research. Existing research on plaque formation mechanism shows that stable plaques contain a large amount of collagen fibers and elastic fibers, and calcification occurs during growth, which is less likely to rupture than unstable plaques. Therefore, there are significant differences in material properties and mechanical properties between the two types of plaques. Existing numerical simulation research on intravascular flow mostly uses ideal models, which cannot provide medical examination and operation plans for specific patients, and has the following problems. First, in the mechanical model, the blood vessel wall and plaque are considered as materials with the same physical properties, and the material model is not distinguished between stable plaques and unstable plaques. Second, in the flow model, blood is considered as a Newtonian fluid, and the quantitative model of macromolecular substances such as red blood cells, proteins, and lipids in patient's blood is not constructed. Third, in the boundary condition, the changes of periodic velocity and periodic pressure in the flow process caused by systolic pressure and diastolic pressure in the blood vessel are not considered. Therefore, the two-way fluid-structure coupling numerical simulation combining the multi-component multiphase flow model based on patient clinical data and pathological data and the solid mechanics model based on the material mechanical properties test of stable plaques, unstable plaques, and blood vessel wall can accurately provide the changes of blood flow parameters in the patient's characteristic area.

[0004] The present application obtains the real blood properties and blood vessel morphology of the patient based on clinical data and pathological data, finds the material performance difference of the two types of plaques and vessel walls by testing the mechanical properties of the plaques and vessel walls, uses the two-way fluid-structure coupling numerical simulation of multi-component and multi-phase flow to obtain the flow velocity, local flow rate and cross-sectional streamline of the typical points in the two types of models, compares the data of the two types of models to assist in judging the stability of the plaques in combination with the numerical simulation results. SUMMARY

[0005] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application develops a preoperative non-invasive plaque stability judgment method combining numerical simulation and medical examination in view of the deficiencies of the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solution steps:

[0007] Step 1, collecting the head and neck clinical data of the patient;

[0008] Step 2, reconstructing the three-dimensional carotid artery lesion stenosis model of the patient by using the data collected in step 1;

[0009] Step 3, collecting the blood flow variation pathological data of the patient;

[0010] Step 4, constructing the multi-component and multi-phase flow model of the patient by using the data collected in step 3;

[0011] Step 5, collecting the stability plaque, unstable plaque and blood vessel wall data after the CEA operation which can be used for scientific research and academic activities after the ethical review;

[0012] Step 6, constructing the two types of two-way fluid-structure coupling models by using the data collected in step 5;

[0013] Step 7, drawing the grid by using the three-dimensional carotid artery lesion stenosis model of the patient reconstructed in step 2, determining the flow boundary condition by using the multi-component and multi-phase flow model of the patient constructed in step 4, determining the solid mechanics boundary condition by using the two types of two-way fluid-structure coupling models constructed in step 6, performing numerical simulation, and detecting the hemodynamic parameters of the characteristic regions in the data set;

[0014] Step 8, assisting in judging the stability of the plaques by targeted preoperative examination;

[0015] Step 9, operation planning and postoperative evaluation.

[0016] Further, in step 1, the head and neck clinical data of the patient includes the patient's head and neck CTA, DSA angiography and operation record. The patient's head and neck CTA and DSA angiography need to be preprocessed in a medical imaging software, and the scale and the characteristic size of the common carotid artery, the internal carotid artery, the external carotid artery and the plaque region are determined in combination with the ultrasound report.

[0017] Further, the step 2 comprises: importing the head and neck image marked with the common carotid artery, internal carotid artery, external carotid artery, plaque area characteristic size in JPG or PNG format into SOLIDWORKS, selecting the research area, and reconstructing the three-dimensional carotid artery lesion stenosis model of the patient by using rotation, scanning, lofting operation.

[0018] As preferred, the three-dimensional carotid artery lesion stenosis model comprises a blood vessel wall, an uneven plaque, and a blood flow pipeline.

[0019] Further, in the step 3, the patient blood flow pathologic data comprises examination data capable of reflecting the thickening, viscosity, aggregation, and coagulation of blood, including blood flow rate, blood viscosity, blood lipid content, and red blood cell electrophoresis time.

[0020] Further, in the step 4, the blood in the patient multi-component and multi-phase flow model comprises a liquid phase composed of blood plasma, HDL, and LDL and a solid phase composed of red blood cells, and the blood flow is regarded as a periodic non-Newtonian fluid flow.

[0021] Further, in the step 5, the stable plaque, unstable plaque, and blood vessel wall data comprise the morphological data and mechanical property test data of the stable plaque, unstable plaque, and blood vessel wall.

[0022] Further, in the step 6, the two-way fluid-structure coupling model comprises blood-unstable plaque-blood vessel wall and blood-stable plaque-blood vessel wall; the deformation displacement and strain of the stable plaque, unstable plaque, and blood vessel wall generated in the carotid artery blood flow are small, and a linear elastic material model can be used, in which the first parameter λ and the second parameter μ of Lamé satisfy the following relationship, and the shear modulus μ is obtained by mechanical property test

[0023] λ = 20 * μ - 2 μ / 3

[0024] Further, the mechanical property test is to measure the shear modulus μ of the plaque by a solid material elastic property tester. The preferred mode is as follows:

[0025] (a) For convenient test, the stable plaque, unstable plaque, and blood vessel wall are longitudinally cut into rectangular samples with a length not less than 40 mm, the width and thickness of both ends and the center of the sample are measured by a vernier caliper, the average value is obtained, the thickness is denoted as t (mm), the width is denoted as b (mm), the sample length is denoted as L (mm), and the length-width ratio is required to be not less than 20, and the width-thickness ratio is controlled to be about 5;

[0026] (b) The sample mass is weighed by a balance and denoted as m (g);

[0027] (c) Support the sample with two intersecting nylon threads, make sure the support points are the inflection points of the vibration, place the impulse exciter and signal receiver at the opposite diagonal positions of the sample. Adjust the force value of the excitation to ensure that the sample can freely vibrate in torsion, and place the sensor directly above the sample to obtain the expected torsional vibration frequency f (Hz).

[0028] (d) After adjustment, measure the damping free vibration curve of the sample to calculate the shear modulus μ.

[0029] The relevant calculation formula is as follows, where B is the shape parameter and A is the empirical correction parameter.

[0030]

[0031] Further, the step 7 comprises the following implementation steps:

[0032] Step 7.1: Software and method selection. COMSOL Multiphysics 6.2 is used for multi-physical field coupling, and fluid flow and solid mechanics modules are selected for two-way fluid-structure coupling numerical simulation of multi-component and multi-phase flow. Under the fluid flow module, in the flow model construction, considering that the blood flow in the carotid artery Re<2000, laminar flow is selected; in the non-Newtonian fluid model selection process, considering that the Eular-Eular model is suitable for the case where the particle diameter in the two-phase fluid is small, the macromolecular substance particle phase in the blood is regarded as a pseudo-fluid and penetrates with the liquid phase, so the Eular-Eular method is selected; in the non-Newtonian fluid model construction process, the red blood cell, HDL, LDL density, particle size, and viscosity data in step 4 are input into the settings of the continuous phase and the dispersed phase; under the solid mechanics module, the roller support boundary is a free boundary and does not contact with the blood; the load boundary is the interface between the blood vessel inner wall and the blood.

[0033] Step 7.2: Boundary condition setting. Under the fluid flow module, due to the influence of systolic pressure and diastolic pressure of the blood vessel, the blood vessel inlet adopts periodic velocity, the internal carotid artery and the external carotid artery are pressure outlets, and are set as periodic pressure. The blood flow velocity of the patient's common carotid artery in n heart cycles is collected and fitted into an inlet velocity curve. The blood pressure of the patient's internal carotid artery and external carotid artery in n heart cycles is collected and fitted into an outlet pressure curve; under the solid mechanics module, the corresponding Lamé parameters are input for the two types of two-way fluid-structure coupling models; under the multi-physical field coupling of fluid-structure coupling, both the force of the fluid acting on the solid and the influence of the solid deformation on the fluid are considered, so the dynamic mesh is set as free deformation and the displacement is specified.

[0034] Step 7.3: Grid independence verification. The fluid domain, solid domain grid is divided, the inlet, internal and external carotid outlet is encrypted; according to the grid number doubling idea gradually expand the grid number for numerical simulation; the current grid and its numerical simulation results of the next grid deviation is less than 5% can be selected for the current grid.

[0035] Step 7.4: Step independence verification. Select 10E-3, 5E-4, 10E-4, 5E-5, 10E-5 for numerical simulation, and gradually select the step size with good convergence for subsequent numerical simulation.

[0036] Step 7.5: Data post-processing. Select two types of two-way fluid-structure interaction model data set WSS low area feature points (such as carotid bifurcation point, plaque shoulder) as typical points, detect flow velocity change, calculate mean value, record stability plaque model typical point flow velocity as v1-v n , instability plaque model typical point flow velocity as v1 * -v n * ; Select carotid bifurcation cross section, plaque stenosis center cross section, plaque distal cross section, plaque proximal cross section as four local flow detection surfaces, calculate the average value, record the local cross section flow of stability plaque model as Q1, Q2, Q3, Q4, the local cross section flow of instability plaque model as Q1 * , Q2 * , Q3 * , Q4 * .

[0037] Further, the step 8 comprises the following steps:

[0038] Step 8.1, using Doppler ultrasound to detect the flow velocity of the typical point of the patient's carotid artery lesion area, recorded as the velocity set V, detecting the local flow cross section velocity, recorded as the velocity set V*, detecting the local flow cross section diameter, recorded as the diameter set D, thus calculating the local flow, the relationship is as follows, recorded as the flow set Q.

[0039] Q = V*πD 2 / 4

[0040] More specifically, if the error of V and v1-v n , Q and Q1-Q4 is less than 5%, it is more likely to be a stable plaque; if the error of V and v1 * -v n * , Q and Q1 * -Q4 * is less than 5%, it is more likely to be an unstable plaque.

[0041] Step 8.2, observe the blood flow changes by DSA angiography and compare with the blood flow streamlines drawn after numerical simulation of two types of two-way fluid-structure coupling models, if the streamlines and flow forms are similar to the stability plaque model, the probability of the stability plaque is large, otherwise, the probability of the instability plaque is large.

[0042] Further, the step 9 comprises: for the patient with multiple site stenosis, the feature region hemodynamic parameter detection and comparison of each site plaque are separately carried out to determine the best operation scheme; after the postoperative consent of the patient, the mechanical property test is carried out on the CEA operation plaque, the parameter setting of the linear elastic material model is corrected, the biological tissue analysis is carried out to determine the plaque type, and the accuracy rate of the auxiliary diagnosis of the method is verified.

[0043] Compared with the prior art, the present application has at least the following beneficial technical effects:

[0044] Firstly, the present application screens the clinical data and pathological data of the patient, determines the content and physical properties of the macromolecular substances in the blood, measures the blood flow rate and physiological pressure in the blood vessel in the heart cycle of the patient, fits into a periodic curve, and constructs a multi-component multi-phase flow non-Newtonian fluid flow model.

[0045] Secondly, the present application first proposes to construct a two-way fluid-structure coupling model reflecting the stability difference of the plaque, and characterizes the mechanical properties of the stability plaque, the instability plaque and the blood vessel wall through solid material elasticity test, and constructs two types of specific models fitting the patient.

[0046] Thirdly, the present application first combines numerical simulation with medical examination to form a preoperative non-invasive method for judging the stability of the plaque. The concepts of typical points, local flow surfaces and cross-sectional streamlines in numerical simulation are applied to medical examination, the characteristic region parameters in the blood vessel flow environment of the patient are positioned through analysis of the numerical simulation results, and the detection site is optimized by preoperative ultrasonic, DSA and other medical image examinations, so as to improve the accuracy of the preoperative plaque stability determination and save the treatment cost of the patient. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 The flow chart of the method of the present application;

[0048] Figure 2 The two-way fluid-structure coupling model diagram of a preferred embodiment of the present application;

[0049] Figure 3 The numerical simulation result display diagram of a preferred embodiment of the present application; wherein, left: Von Mises force (N / m2) distribution of inner wall surface; right: center cross-sectional flow velocity (m / s) and stream line distribution. DETAILED DESCRIPTION

[0050] AsFigure 1 The specific steps of one embodiment of the present application are as follows:

[0051] Step S1: Head and neck clinical data collection. Collect patient head and neck CTA, DSA angiography, surgical records, determine the degree of stenosis, stenosis type, select the complete lesion region including the internal carotid artery, common carotid artery, external carotid artery as the implementation object.

[0052] Pretreatment in medical image software, combined with ultrasound report to determine the scale and characteristic size, import into SOLIDWORKS in JPG or PNG format.

[0053] Step S2: Three-dimensional carotid artery lesion stenosis model reconstruction. Select the study area, use rotation, scanning, lofting operation to reconstruct the patient's carotid artery lesion stenosis model, and perform surface smoothing treatment to optimize the model.

[0054] The carotid artery lesion stenosis model includes three parts: blood vessel wall, uneven plaque, and blood flow pipeline. Measure the stenosis rate and common carotid artery size in the reconstructed model. If the error is less than 1%, the next step can be carried out.

[0055] Step S3: Blood flow pathology data collection. Collect the patient's blood flow rate, blood viscosity, blood lipid content, and red blood cell electrophoresis time test data to evaluate the patient's blood thickening, viscosity, aggregation, and coagulation. Statistics and correction of red blood cell, HDL, LDL, plasma concentration, density, and viscosity data in the collected pathology report.

[0056] Step S4: Construct a multi-component multiphase flow model. Blood flow is regarded as a periodic non-Newtonian fluid flow, which includes a liquid phase composed of plasma, HDL, and LDL, and a solid phase composed of red blood cells.

[0057] Step S5: Plaque and blood vessel wall data collection. Including the morphological data and mechanical property test data of stable plaque, unstable plaque, and blood vessel wall.

[0058] The mechanical property test data is the shear modulus μ of the plaque measured by a solid material elastic property tester, and a material database of stable plaque, unstable plaque, and blood vessel wall is established.

[0059] For convenience of testing, the stable plaque, unstable plaque, and blood vessel wall are longitudinally cut into near-rectangular samples with a length of not less than 40 mm.

[0060] The width and thickness of the sample at both ends and the center are measured using a vernier caliper, and the average value is calculated. The thickness is denoted as t (mm), the width is denoted as b (mm), the sample length is measured and denoted as L (mm), and the length-width ratio is required to be not less than 20, and the width-thickness ratio is controlled at about 5.

[0061] The sample mass is weighed using a balance and recorded as m (g).

[0062] The sample is supported by two cross-shaped nylon wires, ensuring that the support points are the inflection points of the vibration. The pulse exciter and signal receiver are placed diagonally on the sample.

[0063] The support points for sample placement are determined through multiple attempts.

[0064] Note that the force value of the excitation should ensure that the sample can freely vibrate in torsion, and the sensor should be placed directly above the sample 10 mm away to obtain the expected torsional vibration frequency f (Hz).

[0065] After debugging, the measurement is performed, the solid material elastic performance tester is started, the measured b, t, L, m are input into the instrument, the pulse exciter is started to input the excitation force value obtained during debugging, and the damping free vibration curve of the sample is obtained to calculate the shear modulus. The relevant calculation formula is as follows.

[0066]

[0067] Where B is the shape parameter, which can be obtained from the following empirical formula according to the selected sample, and b / t = c.

[0068]

[0069] Where A is an empirical correction parameter that can be obtained by consulting a chart, and can be obtained from the following empirical formula according to the selected sample, and b / t = c.

[0070]

[0071] Step S6: Two-way fluid-structure coupling model construction. The two-way fluid-structure coupling model includes blood-unstable plaque-blood vessel wall, blood-stable plaque-blood vessel wall.

[0072] The deformation displacement and strain of stable plaque, unstable plaque, and blood vessel wall in carotid blood flow are small, and linear elastic material model can be used. In this model, the first parameter λ and the second parameter μ of Lamé satisfy the following relationship, and the shear modulus μ is obtained from the mechanical property test.

[0073] λ = 20 * μ - 2 μ / 3

[0074] Step S7: Characteristic region hemodynamic parameter detection. Numerical simulation is performed on the above model to obtain the blood flow dynamic parameters.

[0075] Software and method selection. COMSOL Multiphysics 6.2 is used for multi-physical field coupling, and two modules of fluid flow and solid mechanics are selected for two-way fluid-structure coupling numerical simulation of multi-component and multi-phase flow.

[0076] Under the fluid flow module, in the flow model construction, considering that the blood flow in the carotid artery Re < 2000, laminar flow is selected. In the fluid properties, the effect of gravity on blood flow needs to be considered, and the gravity option is checked.

[0077] In the process of selecting the non-Newtonian fluid model, considering that the Eular-Eular model is suitable for the case where the particle diameter in two-phase fluid is very small, the flow of macromolecular particles in blood is regarded as a pseudo-fluid, and the liquid phase is mutually permeable, so the Eular-Eular method is selected.

[0078] In the process of constructing the non-Newtonian fluid model, the above red blood cell, HDL, LDL density, particle size, and viscosity data are input into the settings of the continuous phase and the dispersed phase, and the volume fraction of red blood cells is 45%.

[0079] Under the solid mechanics module, the roller support boundary is a free boundary and does not contact with blood; the load boundary is the interface between the blood vessel inner wall and blood.

[0080] Boundary condition setting. Under the fluid flow module, due to the influence of systolic and diastolic pressure, the blood flow velocity of the patient's common carotid artery in n cardiac cycles needs to be collected and fitted into an inlet velocity curve. The blood pressure of the patient's internal and external carotid arteries in n cardiac cycles is collected and fitted into an outlet pressure curve.

[0081] Referring to a specific implementation, the inlet boundary condition is set as follows: the blood vessel inlet is 0.8s as a cardiac cycle, and the periodic inlet velocity of n cardiac cycles with a peak value of 0.2m / s-1.6m / s is adopted. The internal and external carotid arteries are pressure outlets, and are set as periodic pressure with a low peak value of 80mmHg and a high peak value of 120mmHg.

[0082] Under the solid mechanics module, the corresponding Lamé parameters are input for the two types of models; under the multi-physical field coupling of fluid-structure coupling, both the force of fluid acting on the solid and the effect of solid deformation on the fluid are considered, so the dynamic mesh is set as free deformation and the displacement is specified.

[0083] Mesh independence verification. The tetrahedral mesh, the boundary layer mesh, the fluid domain mesh, the solid domain mesh are divided, the inlet, the internal carotid artery outlet, the external carotid artery outlet are encrypted, and the mesh quality is ensured to be good; the mesh number is gradually expanded according to the doubling idea, and the numerical simulation is carried out; the mesh drawing range is 1-500 million meshes; the average flow velocity of the internal carotid artery outlet, the carotid artery inlet, and the external carotid artery outlet at 0.2s is detected, the instantaneous flow velocity of the carotid artery bifurcation point and the plaque center at 0.2s is detected, and the numerical simulation result of the current mesh and the subsequent mesh is less than 5% when the numerical simulation result of the current mesh and the subsequent mesh is less than 5%.

[0084] Step length independence verification. On the basis of selecting a suitable mesh number, 10E-3, 5E-4, 10E-4, 5E-5, and 10E-5 are selected as time steps for numerical simulation, and a step length with better convergence is selected for subsequent implementation steps.

[0085] Data post-processing. Select the plaque distal end, plaque proximal end, and low WSS area in the complex flow region in the two types of models as typical points, record the three-dimensional coordinates of the selected typical points in the reconstructed model, detect the flow velocity change, calculate the average value, and record the flow velocity of the typical points in the stable plaque model as v1-v n , and the flow velocity of the typical points in the unstable plaque model as v1 * -v n * .

[0086] Select the carotid artery bifurcation section, plaque stenosis center section, plaque distal end section, and plaque proximal end section as four local flow detection surfaces, record the distance of the local flow detection surface relative to the bottom surface, calculate the average value, and record the local section flow of the stable plaque model as Q1, Q2, Q3, and Q4, and the local section flow of the unstable plaque model as Q1 * , Q2 * , Q3 * , and Q4 * .

[0087] Select the body region of the two types of models, and use a three-dimensional drawing group to draw the body flow line. Select the number of flow lines from 100 to 1000 to obtain a more accurate internal blood flow diagram of the blood vessel, and export it as a GIF animation of the change of the flow line with time.

[0088] Step S8: Preoperative examination to judge plaque stability. According to the three-dimensional coordinates of the recorded typical points and the positions of the recorded local flow section, the positions of the typical points and the local section in the patient's body are located. The Doppler ultrasound is used to detect the flow velocity of the typical points in the carotid artery lesion region of the patient, and the velocity set V is recorded. The local flow section velocity is detected and recorded as the velocity set V*, and the local flow section diameter is detected and recorded as the diameter set D. Thus, the local flow is calculated, and the relationship is as follows, which is recorded as the flow set Q.

[0089] Q = V * πD 2 / 4

[0090] If V is equal to v1-v n , Q is equal to Q1-Q4, the error is less than 5%, and it is a stable plaque; if V is equal to v1 * -v n * , Q is equal to Q1 * -Q4 * , the error is less than 5%, and it is an unstable plaque.

[0091] Observe the blood flow changes by DSA angiography and draw blood flow streamlines after numerical simulation of the two types of models for comparison, especially pay attention to the changes of streamlines at the plaque, stenosis, bending and bifurcation regions of the blood vessels. If the streamlines and flow patterns are similar to the stable plaque model, it is a stable plaque with a high probability, and vice versa.

[0092] Step S9: surgical planning and postoperative evaluation. For patients with multiple stenosis sites, the characteristic regional hemodynamic parameters of each plaque are detected and compared to determine the best surgical plan. After the patient agrees, the mechanical properties of the CEA resected plaque are tested, and the parameter settings of the linear elastic model are corrected. Biological tissue analysis is performed to determine the plaque type and verify the accuracy of the method for auxiliary diagnosis.

[0093] The above specific embodiments are only used to illustrate the principles of the present application, and are not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and basic characteristics of the present application shall be included in the protection scope of the present application.

Claims

1. A data processing method for preoperatively judging plaque stability noninvasively, characterized by, The steps are as follows: Step 1, collect patient head and neck clinical data; Step 2, reconstruct the patient's three-dimensional carotid artery lesion stenosis model using the data collected in step 1; Step 3, collect patient blood rheology data; Step 4, construct a patient multi-component and multi-phase flow model using the data collected in step 3; Step 5, collect CEA postoperative stable plaque, unstable plaque, and blood vessel wall data that can be used for scientific research and academic activities after ethical review; Step 6, construct two types of two-way fluid-structure coupling models using the data collected in step 5, including blood-unstable plaque-blood vessel wall and blood-stable plaque-blood vessel wall; the deformation displacement and strain of stable plaque, unstable plaque, and blood vessel wall in carotid blood flow are small, and a linear elastic material model is adopted, in which the first parameter λ and the second parameter μ of Lamé satisfy the following relationship, and the shear modulus μ is obtained from the mechanical property test λ = 20 * μ - 2 μ / 3; Step 7, draw a grid using the patient's three-dimensional carotid artery lesion stenosis model reconstructed in step 2, determine the flow boundary conditions using the patient's multi-component and multi-phase flow model constructed in step 4, determine the solid mechanics boundary conditions using the two types of two-way fluid-structure coupling models constructed in step 6, perform numerical simulation, and detect the hemodynamic parameters in the characteristic region of the data set; obtain the flow velocity, local cross-sectional flow, and blood flow streamline data of the typical points in the two types of two-way fluid-structure coupling models; Step 8, compare the data obtained from the preoperative examination with the data obtained from the two types of two-way fluid-structure coupling models in step 7; Step 9, surgical planning and postoperative evaluation.

2. The data processing method for judging plaque stability before operation without incision according to claim 1, characterized in that, In step 1, the patient's head and neck clinical data includes patient's head and neck CTA, DSA angiography, and operation record. The patient's head and neck CTA and DSA angiography need to be preprocessed in medical imaging software, and the scale and carotid artery, internal carotid artery, external carotid artery, and plaque region characteristic size are determined in combination with the ultrasound report.

3. The data processing method for judging plaque stability before operation without incision according to claim 1, characterized in that, Step 2 includes: importing the head and neck image with labeled carotid artery, internal carotid artery, external carotid artery, and plaque region characteristic size into SOLIDWORKS in JPG or PNG format, selecting the study area, and reconstructing the patient's three-dimensional carotid artery lesion stenosis model using rotation, scanning, and lofting operations; the three-dimensional carotid artery lesion stenosis model includes blood vessel wall, uneven plaque, and blood flow pipeline.

4. The data processing method for judging plaque stability before operation without incision according to claim 1, characterized in that, In step 3, the patient's blood rheology data includes examination data that can reflect the thickening, viscosity, aggregation, and coagulation of blood, including blood flow rate, blood viscosity, blood lipid content, and red blood cell electrophoresis time.

5. The data processing method for judging plaque stability before operation without incision according to claim 1, characterized in that, In step 4, the blood in the patient's multi-component and multi-phase flow model includes liquid phase composed of plasma, HDL, and LDL and solid phase composed of red blood cells, and the blood flow is regarded as periodic non-Newtonian fluid flow.

6. The data processing method for judging plaque stability before operation without incision according to claim 1, characterized in that, In step 5, the stable plaque, unstable plaque, and blood vessel wall data include the morphological data and mechanical property test data of stable plaque, unstable plaque, and blood vessel wall.

7. The data processing method for judging plaque stability before operation without incision according to claim 1, characterized in that, the mechanical property test is to measure the shear modulus μ of the plaque by a solid material elastic property tester in the following manner: (a) selecting a sample length of not less than 40 mm, cutting the stable plaque, the unstable plaque and the blood vessel wall longitudinally into rectangular samples, measuring the width and thickness of both ends and the center of the sample by using a vernier caliper, calculating the average value, taking the thickness as t and the width as b, and measuring the sample length as L, and requiring that the length-width ratio of the sample is not less than 20 and the width-thickness ratio is controlled at about 5; (b) weighing the sample mass by using a balance and taking it as m; (c) supporting the sample by using two cross-shaped nylon lines, ensuring that the support points are the inflection points of vibration, placing a pulse exciter and a signal receiver at the opposite positions of the sample, adjusting the excitation force value to ensure that the sample can freely vibrate, and placing a sensor directly above the sample to obtain the expected torsional vibration frequency f; (d) After debugging, the damping free vibration curve of the sample is obtained to calculate the shear modulus μ; the relevant calculation formula is as follows, where B is a shape parameter, is an empirical correction parameter; 。 8. The data processing method for judging plaque stability before operation without incision according to claim 5, characterized in that, the step 7 comprises the following implementation steps: Step 7.1: software and method selection; multi-physical field coupling is performed by using COMSOL Multiphysics 6.2, two modules of fluid flow and solid mechanics are selected for two-way fluid-structure coupling numerical simulation of multi-component and multi-phase flow; under the fluid flow module, in the flow model construction, considering that the Re of the blood flow in the carotid artery is less than 2000, laminar flow is selected; in the non-Newtonian fluid model selection process, considering that the Eular-Eular model is suitable for the case that the particle diameter in the two-phase fluid is small, the macromolecular substance particle phase in the blood is regarded as a pseudo-fluid and penetrates each other with the liquid phase, therefore the Eular-Eular method is selected; in the non-Newtonian fluid model construction process, the density, particle size and viscosity data of the red blood cells, HDL and LDL in step 4 are input into the settings of the continuous phase and the dispersed phase; under the solid mechanics module, the roll support boundary is a free boundary and does not contact with the blood; the load boundary is the interface of the blood vessel inner wall and the blood; Step 7.2: boundary condition setting; under the fluid flow module, due to the influence of the systolic pressure and diastolic pressure of the blood vessel, the blood vessel inlet adopts a periodic velocity, the internal carotid artery and the external carotid artery are pressure outlets and are set as periodic pressure; the blood flow velocity of the common carotid artery of the patient in n heart cycles is collected and fitted into an inlet velocity curve; the blood pressure of the internal carotid artery and the external carotid artery of the patient in n heart cycles is collected and fitted into an outlet pressure curve; under the solid mechanics module, the corresponding Lamé parameters are input for the two types of two-way fluid-structure coupling models; under the multi-physical field coupling of fluid-structure coupling, both the force of the fluid acting on the solid and the influence of the solid deformation on the fluid are considered, therefore the dynamic mesh is set as free deformation and the displacement is specified; Step 7.3: mesh independence verification; the fluid domain and the solid domain are meshed, and the inlet, the internal carotid artery outlet and the external carotid artery outlet are subjected to encryption processing; the grid number is gradually expanded for numerical simulation according to the idea of doubling the grid number; the current grid and the subsequent grid numerical simulation result deviation is less than 5%, and the current grid can be selected. Step 7.4: Step independence verification; select 10E-3, 5E-4, 10E-4, 5E-5, 10E-5 for numerical simulation, and gradually select the step length with good convergence for subsequent numerical simulation; Step 7.5: data post-processing; select the region with low WSS in the two types of two-way fluid-structure coupling model data set as the typical point, detect the flow velocity change, calculate the mean value, and record the stability plaque model typical point flow velocity as v1-v n , and the instability plaque model typical point flow velocity as v1 * -v n * ; The carotid artery bifurcation section, the center section of the plaque stenosis, the distal section of the plaque and the proximal section of the plaque are selected as four local flow detection surfaces, the average value is calculated, and the local section flow of the stable plaque model is recorded as Q1, Q2, Q3 and Q4, and the local section flow of the unstable plaque model is recorded as Q1 * , Q2 * , Q3 * , Q4 * .

9. The data processing method for judging plaque stability before operation without incision according to claim 8, characterized in that, The step 8 comprises the following steps: Step 8.1, using Doppler ultrasound to detect the flow velocity of the typical point of the carotid artery lesion area of the patient, recorded as the velocity set V, detecting the local flow cross-sectional velocity, recorded as the velocity set V*, detecting the local flow cross-sectional diameter, recorded as the diameter set D, and calculating the local flow, the relationship is as follows, recorded as the flow set Q; Q = V * πD 2 / 4 whether the error of V and v1-v n is less than 5%; whether the error of V and v1 * -v n * is less than 5%; whether the error of V and v1 * -Q4 * is less than 5%; Step 8.2, using DSA angiography to observe the blood flow change and comparing the blood flow streamline drawn after the numerical simulation of the two types of two-way fluid-structure coupling model.

10. The data processing method for judging plaque stability before operation without incision according to claim 1, characterized in that, The step 9 comprises: for patients with multiple stenosis sites, the characteristic region hemodynamic parameters of each site plaque are detected and compared to determine the best surgical plan; after the operation, the patient agrees to test the mechanical properties of the CEA operation to remove the plaque, and the parameter setting of the linear elastic material model is corrected.

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