Intracranial aneurysm hemodynamics analysis method and system based on bidirectional fluid-solid coupling

Abstract

The invention provides an intracranial aneurysm hemodynamic parameter and wall stress prediction method based on magnetic resonance angiography, which comprises the following steps of: obtaining magnetic resonance angiography three-dimensional imaging data information of an intracranial aneurysm patient, and performing geometrical shape processing on a three-dimensional data model by adopting 3-matic Medical13.0 software to obtain an aneurysm and aneurysm-carrying artery model; a one-dimensional blood flow solver is used for obtaining the blood flow state of the brain of the patient, wherein the blood flow state comprises the blood flow and pressure of main artery segments around the aneurysm; and internal flow characteristics and wall surface structure parameters of the aneurysm are obtained through bidirectional fluid-solid coupling calculation. According to the method, the blood vessel model based on the focus is constructed, the intratumor hemodynamics and the wall stress are obtained through the fluid mechanics theory and the solid mechanics theory, a more scientific diagnosis basis can be provided for clinicians, and the treatment method is optimized.

Description

Technical Field

[0001] The present invention relates to the cross - field of medical computational fluid dynamics and biomechanics, and particularly relates to an analysis method and system for intracranial aneurysm hemodynamics based on bidirectional fluid - structure interaction. Background Art

[0002] Intracranial aneurysm (IA) is a sac - like bulge of cerebral blood vessels. After rupture, it can cause subarachnoid hemorrhage (SAH), which is a devastating event with high fatality and disability rates. Intracranial aneurysms mostly occur in the cerebral arterial circle of Willis, which is a complex arterial network where several main cerebral arteries converge to form a heptagonal arrangement. The sufficient blood supply to the brain is achieved by the collateral vascular network and the precise vascular dilation and constriction autoregulation system. Clinically, anatomical variations of the circle of Willis are relatively common, including slender artery development and artery absence. From the perspective of blood flow configuration, anatomical variations of the circle of Willis can trigger significant changes in blood flow redistribution and local hemodynamics. The absence of an artery with a relatively large blood flow volume originally will cause other arteries to compensate. Under the influence of the blood flow compensation effect, adverse flow patterns may be triggered. Aneurysms often appear at the arterial bifurcation position along with anatomical variations of the circle of Willis. Previous studies have shown that hypoplasia of arterial branches and a large inflow angle are risk factors for aneurysm occurrence. These studies believe that the occurrence of aneurysms is closely related to abnormal hemodynamic parameters caused by anatomical variations of the circle of Willis. Similarly, anatomical variations can further affect the development and rupture risk of aneurysms by changing the internal flow of unruptured aneurysms.

[0003] Most existing studies predict the hemodynamics inside intracranial aneurysms through computational fluid dynamics (CFD) and construct an IA rupture prediction model. This method can quickly simulate fluid flow in a computer and has advantages such as high efficiency and economy, but it also has obvious deficiencies. On the one hand, in the CFD analysis of IA, blood vessels and aneurysm walls are regarded as rigid, and only the fluid domain is modeled, which does not conform to the real elastic blood vessel wall surface and ignores the influence of arterial wall deformation. On the other hand, as a retrospective study, it is difficult to obtain patient - specific blood flow boundary conditions. The simplified inlet boundary conditions ignore the pulsatile characteristics of the systemic circulation, thus significantly affecting the dynamic calculation results.

[0004] Currently, there is no accurate method to obtain the influence of anatomical variations of the circle of Willis on the internal flow of unruptured aneurysms through dynamic calculations. Therefore, how to construct a method and model to quantitatively evaluate the internal blood flow and aneurysm wall structure parameters during variations and measure the rupture risk of aneurysms is a technical problem to be solved. Summary of the Invention

[0005] The purpose of the present invention is to propose an analysis method and system for intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling, which is used to quantitatively evaluate the influence of the anatomical structure of the Willis circle on the hemodynamics and wall stress in unruptured aneurysms, and to help aneurysm patients receive personalized diagnosis and treatment.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] In a first aspect, the present invention proposes a method for analyzing intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling, which specifically includes the following steps:

[0008] S1. Reconstruct the intracranial aneurysm model and the tumor-bearing artery model based on the patient's CT image data;

[0009] S2. Measure the intracranial aneurysm model and the tumor-bearing artery model, extract the center line of the cerebral vascular network of the intracranial aneurysm patient, and measure the cerebral vascular network of the intracranial aneurysm patient based on the center line to obtain the vascular morphology information of the intracranial aneurysm patient;

[0010] S3, importing the measured vascular morphology information of the intracranial aneurysm patient into a one-dimensional blood flow solver for calculation, obtaining the intracranial aneurysm patient-specific blood flow state, and converting it into blood flow boundary conditions for three-dimensional calculation;

[0011] S4, meshing and condition setting of the intracranial aneurysm model and the tumor-bearing artery model, and obtaining the intracranial aneurysm hemodynamic parameters and aneurysm wall structure parameters through bidirectional fluid-solid coupling calculation;

[0012] S5. Summarize the intracranial aneurysm hemodynamic parameters and aneurysm wall structure parameters and output the results.

[0013] Preferably, the reconstruction of the intracranial aneurysm model and the tumor-bearing artery model based on the patient's CT image data specifically includes the following steps:

[0014] S11. Obtain the Dicom format magnetic resonance vascular three-dimensional imaging data of patients with intracranial aneurysms;

[0015] S12, after converting into a three-dimensional data model in an STL format file using Mimics 21.0, trimming and smoothing the three-dimensional data model in the STL format file using 3-maticMedical13.0;

[0016] S13, importing the STL format file 3D data model processed by S12 into SpaceClaim 2022R1, generating wall thickness to obtain the intracranial aneurysm model and the tumor-bearing artery model;

[0017] The step S12 is specifically as follows:

[0018] Create a new mask in Mimics 21.0, retain the target position, and remove the redundant parts;

[0019] Perform threshold segmentation based on the gray value, segment the tissues with a large difference in gray value, and obtain the tissues with similar gray values;

[0020] Set the threshold size to generate the target tissue and calculate the entity;

[0021] Copy the entity to 3-matic Medical 13.0 to remove the redundant triangular patches, perform local smoothing, and export it as a 3D data model in STL format file.

[0022] Preferably, the vascular morphological information of the intracranial aneurysm patient includes the equivalent diameter of the cerebral blood vessels of the intracranial aneurysm patient and the length of the blood vessel along the center line.

[0023] Preferably, obtaining the specific blood flow state of the intracranial aneurysm patient includes modifying parameters in a one-dimensional blood flow solver, including blood vessel length, radius, thickness, and elastic modulus, and calculating the flow rate and pressure of each arterial segment of the cerebral blood vessels.

[0024] Preferably, the conversion to a blood flow boundary condition for three-dimensional calculation is specifically: writing a user-defined function file UDF for the inlets and outlets of the intracranial aneurysm model and the parent artery model, including defining the inlet condition as a blood flow velocity change curve within one cardiac cycle and defining the outlet as a pressure change curve within one cardiac cycle, and the data are all obtained by calculating with a one-dimensional blood flow solver.

[0025] Preferably, in Fluent 2022R1, perform mesh generation on the intracranial aneurysm model and the parent artery model:

[0026] The mesh generation uses an unstructured hexahedral core mesh, with the minimum sieve hole size of 0.1 mm and the maximum sieve hole size of 0.5 mm;

[0027] The number of volume meshes of the intracranial aneurysm model and the parent artery model is more than 500,000.

[0028] Preferably, in Fluent 2022R1, perform condition setting on the intracranial aneurysm model and the parent artery model:

[0029] Set the intracranial aneurysm model and the parent artery model as a uniform, incompressible, linearly elastic solid, with a density of 1100 kg / m 3 , a Poisson's ratio of 0.49, and an elastic modulus of 1×10 6 Pa, and the blood property is set as an incompressible Newtonian fluid with a density of 1050 kg / m 3, the viscosity is 0.0035 Pa·s, and the blood flow pattern is set to laminar flow;

[0030] The 1 s cardiac cycle is divided into 50 standard time steps with a step size of 0.02 s;

[0031] The inlet condition is defined as the blood flow velocity change curve within one cardiac cycle, and the outlet is defined as the pressure change curve within one cardiac cycle. The data are all obtained by calculating with a one-dimensional blood flow solver;

[0032] The inlet and outlet cross-sections of the intracranial aneurysm model and the parent artery model are fixed, and the outer surface of the blood vessel wall is free and unconstrained.

[0033] Preferably, the hemodynamic parameters in the intracranial aneurysm include: the maximum wall shear stress WSS, the minimum WSS, the average WSS, the low WSS area, the high WSS area, the oscillatory shear index OSI, and the wall pressure in the aneurysm; the aneurysm wall structure parameters include the wall deformation displacement and the von Mises stress.

[0034] Preferably, in the one-dimensional blood flow solver, the blood vessel network is represented as a circuit composed of a series of electronic components, and each arterial segment is discretized into one or more components; the specific impedance, inductance, and capacitance of the components depend on the characteristics and dimensions of the vessel, including elasticity, length, and radius; by iteratively solving the circuit network, the instantaneous current and voltage of the circuit are obtained; finally, the solved current and voltage values are converted into flow rate and pressure;

[0035] The blood flow follows the continuity equation and the momentum conservation equation, based on the following formulas:

[0036]

[0037] where t, z, ρ, and A are time, axial coordinate, blood density, and cross-sectional area respectively, U is the average axial velocity, p is the average cross-sectional pressure, and f is the viscous force per unit length.

[0038] On the other hand, the present invention proposes an analysis system for the hemodynamics of intracranial aneurysms based on bidirectional fluid-structure interaction. The system is implemented by using any of the above-mentioned analysis methods for the hemodynamics of intracranial aneurysms based on bidirectional fluid-structure interaction, and includes: an intracranial aneurysm model and a parent artery model construction module, an intracranial aneurysm patient's blood vessel morphology information model construction module, an intracranial aneurysm patient's specific blood flow state calculation module, an intracranial aneurysm hemodynamic parameter and aneurysm wall structure parameter model construction module, and a result output module.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The present invention uses a method combining a one-dimensional blood flow solver and FSI analysis to study the hemodynamics within intracranial aneurysms and the structural mechanics of the aneurysm wall, which has significant advantages, especially in terms of risk assessment, treatment optimization, and filling research gaps. This method quickly simulates the overall blood flow characteristics of the vascular network through a one-dimensional blood flow model, and then combines FSI analysis to perform high-precision three-dimensional simulations on the local area of the aneurysm, thereby comprehensively capturing the interaction relationship between hemodynamics and aneurysm wall mechanics. This multi-scale and multi-physics coupling method not only improves the computational efficiency but also ensures accurate analysis of key regions, providing more comprehensive and realistic simulation results for the study of the pathological mechanism of intracranial aneurysms.

[0041] (2) The present invention can be used to quantitatively evaluate the change in the overall blood flow configuration of the Willis circle caused by the anatomical variation of the Willis circle, which in turn affects the rupture risk of intracranial aneurysms. Description of the Drawings

[0042] Figure 1 is the implementation flowchart of the method for analyzing the hemodynamics of intracranial aneurysms based on two-way fluid-structure interaction proposed by the present invention;

[0043] Figure 2 is the result diagram obtained by using the intracranial aneurysm model and the parent artery model construction module of the present invention;

[0044] Figure 3 is the result diagram obtained by using the patient-specific blood flow state calculation module for intracranial aneurysms of the present invention;

[0045] Figure 4 is the result diagram obtained by using the module for constructing the hemodynamic parameters within intracranial aneurysms and the structural parameter model of the aneurysm wall of the present invention;

[0046] Figure 5 is the structural diagram of the module for analyzing the hemodynamics of intracranial aneurysms based on two-way fluid-structure interaction proposed by the present invention. Detailed Embodiments

[0047] The technical solutions of the present invention will be specifically described below with reference to the accompanying drawings.

[0048] Studies in recent years have shown that the occurrence of aneurysms is related to the anatomical structure of the Willis circle, such as poor arterial development, local arterial stenosis, and large curvature, which significantly changes the original hemodynamic environment and causes the aneurysm wall to degenerate, inducing the occurrence of aneurysms. Similarly, the anatomical structure of the Willis circle will also have a negative impact on the rupture risk of unruptured aneurysms, but there are few related studies and a lack of accurate, efficient and low-cost simulation tools. In view of the shortcomings of the prior art, the present invention constructs an analysis method and system for intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling, which is used to quantitatively evaluate the influence of the anatomical structure of the Willis circle on the hemodynamics and wall stress in unruptured aneurysms, and provide assistance for aneurysm patients to receive personalized diagnosis and treatment.

[0049] refer to Figure 1 The present invention proposes a method for analyzing the hemodynamics of intracranial aneurysms based on bidirectional fluid-solid coupling, which specifically includes the following steps:

[0050] S1. Reconstruct the intracranial aneurysm model and the tumor-bearing artery model based on the patient's CT image data;

[0051] S2. Measure the intracranial aneurysm model and the tumor-bearing artery model, extract the center line of the cerebral vascular network of the intracranial aneurysm patient, and measure the cerebral vascular network of the intracranial aneurysm patient based on the center line to obtain the vascular morphology information of the intracranial aneurysm patient;

[0052] S3, importing the measured vascular morphology information of the intracranial aneurysm patient into a one-dimensional blood flow solver for calculation, obtaining the intracranial aneurysm patient-specific blood flow state, and converting it into blood flow boundary conditions for three-dimensional calculation;

[0053] S4, meshing and condition setting of the intracranial aneurysm model and the tumor-bearing artery model, and obtaining the intracranial aneurysm hemodynamic parameters and aneurysm wall structure parameters through bidirectional fluid-solid coupling calculation;

[0054] S5. Summarize the intracranial aneurysm hemodynamic parameters and aneurysm wall structure parameters and output the results.

[0055] In this embodiment, the reconstruction of the intracranial aneurysm model and the tumor-bearing artery model based on the patient's CT image data specifically includes the following steps:

[0056] S11. Obtain the Dicom format magnetic resonance vascular three-dimensional imaging data of patients with intracranial aneurysms;

[0057] S12, after converting into a three-dimensional data model in an STL format file using Mimics 21.0, trimming and smoothing the three-dimensional data model in the STL format file using 3-maticMedical13.0;

[0058] S13. Import the 3D data model of the STL format file processed in S12 into SpaceClaim 2022R1 to generate an intracranial aneurysm model and a parent artery model with a wall thickness of (0.2 mm);

[0059] The specific steps of S12 are as follows:

[0060] Create a new mask in Mimics 21.0, retain the target position, and remove the redundant parts;

[0061] Perform threshold segmentation based on the gray value, segment the tissues with a large difference in gray value, and obtain the tissues with similar gray values;

[0062] Set the threshold size to generate the target tissue and calculate the entity;

[0063] Copy the entity to 3-matic Medical13.0 to remove the redundant triangular patches, perform local smoothing processing, and export it as a 3D data model of an STL format file.

[0064] In this embodiment, the vascular morphological information of the intracranial aneurysm patient includes the equivalent diameter of the cerebral blood vessels of the intracranial aneurysm patient and the length of the blood vessel along the center line.

[0065] In this embodiment, obtaining the specific blood flow state of the intracranial aneurysm patient includes modifying parameters in the one-dimensional blood flow solver, including blood vessel length, radius, thickness, and elastic modulus, and calculating the flow rate and pressure of each arterial segment of the cerebral blood vessels.

[0066] In this embodiment, the conversion to a blood flow boundary condition available for three-dimensional calculation is specifically: writing a user-defined function file UDF for each inlet and outlet boundary of the intracranial aneurysm model and the parent artery model, including defining the inlet condition as a blood flow velocity change curve within one cardiac cycle and defining the outlet as a pressure change curve within one cardiac cycle, and the data are all calculated by the one-dimensional blood flow solver.

[0067] In this embodiment, mesh generation is performed on the intracranial aneurysm model and the parent artery model in Fluent 2022R1:

[0068] The mesh generation uses an unstructured hexahedron core mesh, with a minimum sieve hole size of 0.1 mm and a maximum sieve hole size of 0.5 mm;

[0069] The number of volume meshes of the intracranial aneurysm model and the parent artery model is more than 500,000.

[0070] In this embodiment, condition setting is performed on the intracranial aneurysm model and the parent artery model in Fluent 2022R1:

[0071] The intracranial aneurysm model and the parent artery model are set as homogeneous, incompressible, linearly elastic solids with a density of 1100 kg / m 3 , a Poisson's ratio of 0.49, and an elastic modulus of 1×10 6 Pa. The blood properties are set as an incompressible Newtonian fluid with a density of 1050 kg / m 3 , a viscosity of 0.0035 Pa·s, and the blood flow pattern is set as laminar flow;

[0072] The 1s cardiac cycle is divided into 50 standard time steps with a step size of 0.02s;

[0073] The inlet condition is defined as the blood flow velocity change curve within one cardiac cycle, and the outlet is defined as the pressure change curve within one cardiac cycle. The data are all obtained by calculating with a one-dimensional blood flow solver;

[0074] The inlet and outlet cross-sections of the intracranial aneurysm model and the parent artery model are fixed, and the outer surface of the blood vessel wall is free and unconstrained.

[0075] In this embodiment, the hemodynamic parameters in the intracranial aneurysm include: the maximum wall shear stress WSS, the minimum WSS, the average WSS, the low WSS area (LSA, <10 Pa), the high WSS area (HSA, >50 Pa), the oscillatory shear index OSI, and the wall pressure; the aneurysm wall structure parameters include the wall deformation displacement and the von Mises stress.

[0076] In this embodiment, in the one-dimensional blood flow solver, the blood vessel network is represented as a circuit composed of a series of electronic components, and each arterial segment is discretized into one or more components; the specific impedance, inductance, and capacitance of the components depend on the characteristics and dimensions of the vessel, including elasticity, length, and radius; by iteratively solving the circuit network, the instantaneous current and voltage of the circuit are obtained; finally, the solved current and voltage values are converted into flow rate and pressure;

[0077] The blood flow follows the continuity equation and the momentum conservation equation, based on the following formulas:

[0078]

[0079] where t, z, ρ, and A are time, axial coordinate, blood density, and cross-sectional area respectively, U is the average axial velocity, p is the average cross-sectional pressure, and f is the viscous force per unit length.

[0080] On the other hand, the present invention proposes an analysis system for intracranial aneurysm hemodynamics based on two-way fluid-structure interaction. The system is implemented by using any of the above-mentioned analysis methods for intracranial aneurysm hemodynamics based on two-way fluid-structure interaction, and includes:

[0081] An intracranial aneurysm model and parent artery model construction module, which is used to convert the three-dimensional magnetic resonance angiography data of the intracranial aneurysm patient in Dicom format into a three-dimensional data model in STL format by using Mimics 21.0, and then trim and smooth the three-dimensional data model of the STL format file by using 3-matic Medical13.0, and then generate a wall thickness in SpaceClaim 2022R1 to obtain an intracranial aneurysm model and a parent artery model;

[0082] An intracranial aneurysm patient vascular morphology information model construction module, which is used to extract the centerline of the cerebrovascular network of the intracranial aneurysm patient, and measure the cerebrovascular network of the intracranial aneurysm patient according to the centerline to obtain the vascular morphology information of the intracranial aneurysm patient;

[0083] An intracranial aneurysm patient specific blood flow state calculation module, which is used to import the measured vascular morphology information of the intracranial aneurysm patient into a one-dimensional blood flow solver for calculation, perform operations through pyNS (python 2.6), obtain the flow rate and pressure information of each artery of the intracranial aneurysm patient, and write UDF files for the inlet and outlet boundaries of the intracranial aneurysm model and the parent artery model;

[0084] An intracranial aneurysm internal hemodynamic parameter and aneurysm wall structure parameter model construction module, which is used to perform mesh division and condition setting on the intracranial aneurysm model and the parent artery model in Fluent2022R1, use the built-in FSI module for solution, select a pressure-based solver, discretize the fluid domain control equation by using the finite volume method, solve the pressure-velocity coupling algorithm by using the semi-implicit method (SIMPLE) of the pressure coupling equations, add five layers of boundary layer meshes to the fluid boundary region, use the linear finite element method to solve the numerical solution of the solid domain, and process the fluid mesh deformation problem by using the dynamic mesh technology of the diffusion smoothing method, and use the partition strong coupling algorithm to coordinate the data exchange between the fluid and the solid, and finally calculate the intracranial aneurysm internal hemodynamic parameters and aneurysm wall structure parameters;

[0085] A result output module, which is used to summarize the hemodynamic parameters of the maximum WSS, minimum WSS, average WSS, LSA, HSA, OSI, and wall pressure in the intracranial aneurysm and the aneurysm wall structure parameters of the wall deformation displacement and normal stress, and then output the results.

[0086] In summary, the present invention uses a one-dimensional blood flow solver to first solve the overall blood flow situation of the patient's Willis circle, and then uses it as the boundary condition of the three-dimensional geometric model of the intracranial aneurysm and the parent artery to complete the FSI calculation. Figure 2The figure is the result obtained by using the intracranial aneurysm model and parent artery model construction module of the present invention, showing four intracranial aneurysm models and parent artery models located at different positions; among them, (a): ACoA aneurysm, (b): MCA aneurysm, (c): ICA aneurysm, (d): PCoA aneurysm; Figure 3 The figure is the result obtained by using the patient-specific blood flow state calculation module for intracranial aneurysms of the present invention, showing the average flow rate (ml / min) of each artery in the Willis circle within one cardiac cycle, reflecting the influence of the absence of the ACA-A1 segment and PCA-P1 segment of the cerebral arteries on the overall blood flow configuration of the Willis circle; (a): Schematic diagram of the simulated arterial network of the Willis circle, (b): Complete Willis circle, (c): Absence of L-ACA-A1, (d) Absence of R-ACA-A1, (e): Absence of L-PCA-P1, (f): Absence of R-PCA-P1. Figure 4 The figure is the result obtained by using the intracranial aneurysm hemodynamic parameter and aneurysm wall structure parameter model construction module of the present invention, showing the comparison diagram of the wall von Mises stress distribution of four intracranial aneurysms located at different positions at the peak moment of cardiac systole, (a): ACoA aneurysm, (b): MCA aneurysm, (c): ICA aneurysm, (d): PCoA aneurysm.

[0087] The above are the preferred embodiments of the present invention. All changes made according to the technical solution of the present invention, when the functions and effects produced do not exceed the scope of the technical solution of the present invention, shall fall within the protection scope of the present invention.

Claims

1. A method for analyzing intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling, characterized in that: The specific steps include: S1. Reconstruct the intracranial aneurysm model and the tumor-bearing artery model based on the patient's CT image data; S2. Measure the intracranial aneurysm model and the tumor-bearing artery model, extract the center line of the cerebral vascular network of the intracranial aneurysm patient, and measure the cerebral vascular network of the intracranial aneurysm patient based on the center line to obtain the vascular morphology information of the intracranial aneurysm patient; S3, importing the measured vascular morphology information of the intracranial aneurysm patient into a one-dimensional blood flow solver for calculation, obtaining the intracranial aneurysm patient-specific blood flow state, and converting it into blood flow boundary conditions for three-dimensional calculation; S4, meshing and condition setting of the intracranial aneurysm model and the tumor-bearing artery model, and obtaining the intracranial aneurysm hemodynamic parameters and aneurysm wall structure parameters through bidirectional fluid-solid coupling calculation; S5. Summarize the intracranial aneurysm hemodynamic parameters and aneurysm wall structure parameters and output the results.

2. The method for analyzing intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling according to claim 1, characterized in that: The method of reconstructing the intracranial aneurysm model and the tumor-bearing artery model based on the patient's CT image data specifically includes the following steps: S11. Obtain the Dicom format magnetic resonance vascular three-dimensional imaging data of patients with intracranial aneurysms; S12, after converting into a three-dimensional data model in an STL format file using Mimics 21.0, trimming and smoothing the three-dimensional data model in the STL format file using 3-maticMedical13.0; S13, importing the STL format file 3D data model processed by S12 into SpaceClaim 2022R1, generating wall thickness to obtain the intracranial aneurysm model and the tumor-bearing artery model; The step S12 is specifically as follows: Create a new mask in Mimics 21.0, keep the target position, and remove the redundant parts; Threshold segmentation is performed based on grayscale values ​​to segment tissues with large grayscale value differences and obtain tissues with similar grayscale values; Set the threshold size to generate the target organization and calculate the entity; The entity was copied to 3-matic Medical 13.0 to remove redundant triangular faces, and local smoothing was performed, and then exported as a three-dimensional data model in STL format.

3. The method for analyzing intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling according to claim 1, characterized in that: The vascular morphology information of the intracranial aneurysm patient includes the equivalent diameter of the cerebral blood vessels of the intracranial aneurysm patient and the length of the blood vessels along the center line.

4. The method for analyzing intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling according to claim 1, characterized in that: The method of obtaining the intracranial aneurysm patient-specific blood flow state includes modifying parameters in a one-dimensional blood flow solver, including blood vessel length, radius, thickness and elastic modulus, and calculating the flow rate and pressure of each arterial segment of the cerebral blood vessels.

5. The method for analyzing intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling according to claim 1, characterized in that: The conversion into blood flow boundary conditions that can be used for three-dimensional calculation is specifically: writing a user-defined function file UDF for the inlet and outlet boundaries of the intracranial aneurysm model and the tumor-bearing artery model, including defining the inlet condition as a blood flow velocity change curve within a cardiac cycle, and defining the outlet as a pressure change curve within a cardiac cycle, and the data are all obtained by calculation using a one-dimensional blood flow solver.

6. The method for analyzing intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling according to claim 1, characterized in that: The intracranial aneurysm model and the tumor-bearing artery model were meshed in Fluent 2022R1: The meshing adopts unstructured hexahedral core mesh, with the minimum mesh size of 0.1 mm and the maximum mesh size of 0.5 mm; The number of body grids of the intracranial aneurysm model and the tumor-bearing artery model is more than 500,000.

7. The method for analyzing intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling according to claim 1, characterized in that: Conditions of the intracranial aneurysm model and the tumor-bearing artery model were set in Fluent 2022R1: The intracranial aneurysm model and the parent artery model were set as uniform, incompressible, linear elastic solids with a density of 1100 kg / m 3 , Poisson's ratio is 0.49, and the elastic modulus is 1×10 6 Pa, blood properties are set to be incompressible Newtonian fluid, density is 1050 kg / m 3 , viscosity was 0.0035 Pa·s, and the flow mode of blood was set to laminar flow; The 1-s cardiac cycle is divided into 50 standard time steps with a step length of 0.02 s; The inlet condition is defined as the blood flow velocity change curve within a cardiac cycle, and the outlet is defined as the pressure change curve within a cardiac cycle. The data are calculated by a one-dimensional blood flow solver. The inlet and outlet cross sections of the intracranial aneurysm model and the tumor-bearing artery model are fixed, and the outer surface of the blood vessel wall is free and unconstrained.

8. The method for analyzing intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling according to claim 1, characterized in that: The hemodynamic parameters in the intracranial aneurysm include: maximum wall shear stress WSS, minimum WSS, average WSS, low WSS area, high WSS area, shear oscillation index OSI, and wall pressure in the aneurysm; the aneurysm wall structure parameters include wall deformation displacement and paradigm stress.

9. The method for analyzing intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling according to claim 1, characterized in that: In the one-dimensional blood flow solver, the vascular network is represented as a circuit composed of a series of electronic components, and each arterial segment is discretized into one or more components; the specific impedance, inductance and capacitance of the components depend on the characteristics and size of the container, including elasticity, length and radius; by iteratively solving the circuit network, the instantaneous current and voltage of the circuit are obtained; finally, the solved current and voltage values ​​are converted into flow and pressure; Blood flow follows the continuity equation and the momentum conservation equation, based on the following formula: where t, z, ρ and A are time, axial coordinate, blood density and cross-sectional area, respectively; U is the average axial velocity; p is the average cross-sectional pressure; and f is the viscous force per unit length.

10. An analysis system for intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling, characterized in that: The system is implemented by the analysis method of intracranial aneurysm hemodynamics based on bidirectional fluid-solid coupling as described in any one of claims 1 to 9, including: an intracranial aneurysm model and a tumor-bearing artery model construction module, an intracranial aneurysm patient vascular morphology information model construction module, an intracranial aneurysm patient-specific blood flow state calculation module, an intracranial aneurysm hemodynamic parameters and aneurysm wall structure parameter model construction module, and a result output module.

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