Arterial aneurysm virtual stent implantation simulation method based on spring analogy method

Abstract

The invention discloses an aneurysm virtual stent implantation simulation method based on a spring analogy method. The method comprises the following steps: reconstructing a three-dimensional model of a preoperative tumor-carrying main blood vessel and a mother blood vessel after aneurysm reduction based on clinical imaging data; extracting a first blood vessel center line, and constructing a virtual stent initialization model; expanding the virtual stent initialization model through a spring analogy virtual stent rapid algorithm, and determining a three-dimensional model of the virtual stent after being expanded in the individualized blood vessel; and calculating curative effect evaluation parameters through a rapid algorithm based on the porosity of the tumor neck cambered surface of the virtual stent. According to the method, the real movement form of stent unfolding can be simulated, the simulation calculation time and the curative effect evaluation duration of the stent unfolding in the blood vessel can be shortened in a large scale, and real-time guidance in the aneurysm virtual intervention process is achieved.

Description

Technical Field

[0001] The present application relates to the field of biomedical engineering and computer science, and more specifically, to a method for simulating aneurysm virtual stent implantation based on a spring analogy method. Background Art

[0002] Intracranial aneurysm is a vascular disease in which a cerebral aneurysm-like protrusion is formed by the localized abnormal expansion of the intracranial artery wall. The subarachnoid hemorrhage caused by rupture has a high mortality and disability rate. According to statistics, the prevalence of unruptured intracranial aneurysms in people around 50 years old is about 3% worldwide. The rupture of intracranial aneurysms is the main cause of spontaneous subarachnoid hemorrhage, with a global incidence of about 6.1 / 100,000 person-years. Most patients have obvious neurological dysfunction, which seriously affects the quality of life of patients.

[0003] The blood flow guiding device has a high occlusion rate for aneurysm treatment and can help doctors accurately guide the treatment equipment to the aneurysm site to ensure the accuracy and effectiveness of the treatment. The virtual stent can effectively simulate the shape of the blood flow guiding device in the tumor-bearing vessel, and the improvement of the blood flow in the vessel by the blood flow guiding device can be obtained through simulation analysis, so as to provide doctors with judgment on the postoperative efficacy. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide an aneurysm virtual stent implantation simulation method based on the spring analogy method, which is committed to promoting advanced aneurysm virtual stent technology and bringing important innovations to the medical industry. By integrating computer graphics and medical imaging technology, a new surgical simulation and program planning tool is provided to improve the accuracy and safety of surgery. The virtual stent fast algorithm is used, and the Simplex grid method is used to reasonably apply shear force and bending force through spring analogy to make the simulation more realistic and closer to the actual shape of the stent after deployment. This virtual stent technology not only has advantages in preoperative planning, but also can provide real-time guidance for doctors to ensure the best results during surgery.

[0005] A first aspect of the present invention provides a method for simulating aneurysm virtual stent implantation based on a spring analogy method, comprising:

[0006] Acquiring clinical imaging data; the clinical imaging data at least includes the patient's preoperative vascular imaging data;

[0007] Reconstructing a three-dimensional model of the preoperative tumor-bearing main vessel and the mother vessel after aneurysm restoration based on the analysis of the clinical imaging data; the three-dimensional model of the preoperative tumor-bearing main vessel and the mother vessel after aneurysm restoration includes a three-dimensional model of the preoperative tumor-bearing main vessel and a three-dimensional model of the mother vessel after aneurysm restoration;

[0008] Extracting the centerline of the first blood vessel through the three-dimensional model of the parent blood vessel after the aneurysm is restored;

[0009] Constructing a virtual stent initialization model based on the centerline of the first blood vessel;

[0010] Based on a fast algorithm of a spring analogy virtual support, the virtual support initialization model is expanded to determine a three-dimensional model of the virtual support;

[0011] Based on the preoperative three-dimensional model of the tumor-bearing main blood vessel and the three-dimensional model of the virtual stent, analysis is performed, and the efficacy evaluation parameters are calculated by a fast algorithm based on the arc surface porosity of the virtual stent neck.

[0012] In this scheme, the analysis based on the clinical imaging data to reconstruct the three-dimensional model of the preoperative tumor-bearing main vessel and the mother vessel after aneurysm restoration includes:

[0013] By analyzing the clinical imaging data, a three-dimensional model of the main tumor-bearing blood vessels before surgery is reconstructed;

[0014] Preprocessing the three-dimensional model of the preoperative tumor-bearing main blood vessel;

[0015] Generate a second blood vessel centerline based on the preprocessed three-dimensional model of the main tumor-bearing vessel before surgery, truncate the parent blood vessels at both ends of the aneurysm in the preprocessed three-dimensional model of the main tumor-bearing vessel before surgery, fit the centerline segment of the aneurysm area according to the second blood vessel centerline of the parent blood vessels at both ends of the aneurysm, and perform discretization on the centerline segment;

[0016] Obtaining the lumen contour of the parent vessel end close to the aneurysm;

[0017] The lumen contour is fitted and transitioned through discrete points obtained through discretization processing to obtain a three-dimensional model of the parent blood vessel after aneurysm restoration.

[0018] In this solution, the pre-processing of the three-dimensional model of the tumor-bearing main blood vessel before surgery includes:

[0019] Reconstructing the mesh of the three-dimensional model of the preoperative tumor-bearing main blood vessel;

[0020] The triangular mesh of the reconstructed three-dimensional model of the main tumor-bearing blood vessels before surgery is converted into a Simplex mesh.

[0021] In this solution, the step of constructing a virtual stent initialization model based on the centerline of the first blood vessel includes:

[0022] Determine a plurality of first nodes on the centerline of the first blood vessel; the number of the first nodes is determined according to the curvature of the stent wire;

[0023] Analyze the centerline of the first blood vessel to determine the tangent direction of each first node on the centerline of the first blood vessel;

[0024] Sequentially draw a circle with a preset initial radius and perpendicular to the corresponding tangent direction with each first node as the center;

[0025] Determine the number of second nodes on each circle based on the total number of stent filaments of the virtual stent, and evenly discretize the second nodes on each circle; the number of the second nodes is determined according to the number of stent filaments;

[0026] A virtual support initialization model is constructed by performing positive and negative spiral sorting on the second nodes on the adjacent circles, and the second nodes are determined as support nodes;

[0027] The diamond mesh of the virtual support initialization model is converted into a Simplex mesh.

[0028] In this solution, the virtual support fast algorithm based on spring analogy is used to expand the virtual support initialization model to determine the virtual support three-dimensional model, including:

[0029] The expansion force of the stent itself is determined as the internal force, and the resistance encountered by the stent when it expands and contacts the inner wall of the blood vessel is determined as the external force;

[0030] The stent nodes are assumed to be particles that follow the laws of physics, the mass of the particles of the stent nodes is set, and the weight factors of the internal and external forces are obtained through the tensile test of the stent and the tensile test of the intracranial vascular tissue; the weight factors of the internal and external forces are used to determine the proportion of the internal force to the external force on the stent nodes;

[0031] Iteratively expand the virtual support based on the motion trajectory and internal and external forces of the support node. When the internal and external forces of the support node reach a balanced state, the expansion of the support node in the direction perpendicular to the tangent line is terminated accordingly.

[0032] The deployment of the stent is assumed to be the overall movement of multiple positive and negative helical springs of the same material and model. The moment and axial force on a single stent wire are determined through mechanical analysis of the physical stent.

[0033] The stent is compared to a spring to conduct a spring mechanical property experiment of the stent and a single stent wire, and the bending moment and torque of the micro-element stent wire are calculated by the micro-element method.

[0034] Applying the bending moment and torque of the micro-element stent wire to the stent nodes of the virtual stent in the form of force to determine the stent tangential force;

[0035] The virtual stent is unfolded by the internal and external forces perpendicular to the tangential direction and the tangential force of the stent analogous to the spring, and the three-dimensional model of the virtual stent is determined.

[0036] This plan also includes:

[0037] The multiple ratio of the tangential force of the bracket is determined according to the distance from the bracket node to the end point of the center line, and the tangential force of the bracket is adjusted.

[0038] In this solution, the virtual support is iteratively expanded based on the motion trajectory and internal and external forces of the support node. When the internal and external forces of the support node reach a balanced state, the expansion of the support node in the direction perpendicular to the tangent line is terminated accordingly, including:

[0039] The stent deployment includes two stages; the two stages are the non-wall-touching stage and the wall-touching stage;

[0040] After each iterative expansion, the distance between the current position of the stent node and the position of the nearest Simplex grid node of the main tumor-bearing vessel before surgery is calculated;

[0041] When the distance is greater than or equal to a preset distance threshold, the expansion of the support node is in a stage where the support node does not touch the wall, and the support node expands outwards under the action of internal force;

[0042] When the distance is less than a preset distance threshold, the expansion of the support node enters the wall-touching stage, and the support node expands outward under the combined action of internal and external forces;

[0043] When the internal force is balanced with the external force, the stent node stops expanding.

[0044] This plan also includes:

[0045] The maximum and minimum values ​​of the distance between the nodes of the stent when the solid stent is only subjected to axial pressure and perpendicular to the axial pressure are set as the distance restriction conditions between the nodes of the stent; the distance between the nodes of the stent includes the distance between the nodes of the stent wires and the distance between the nodes of the stent segments;

[0046] When the support nodes of the virtual support meet the distance restriction condition between the support nodes, determining that the support nodes reach a balanced position;

[0047] When all the stent points reach the equilibrium position, the final placement of the virtual stent is determined.

[0048] In this solution, the analysis is performed based on the preoperative tumor-bearing main vessel three-dimensional model and the virtual stent three-dimensional model, and the efficacy evaluation parameters are calculated by a fast algorithm based on the arc surface porosity of the virtual stent neck, including:

[0049] The efficacy evaluation parameters include at least the neck arc surface porosity;

[0050] Dividing the tumor neck plane based on the preoperative three-dimensional model of the tumor-bearing main blood vessel, and obtaining contour position data of the tumor neck plane;

[0051] Calculating the intersection of the contour position data and the stent wire, and determining the node formed by the arc surface gap of the tumor neck after the stent wire is projected based on the preset stent wire diameter;

[0052] Calculate the sum of the polygonal areas formed by each node to determine the gap area of ​​the arc surface of the neck of the tumor;

[0053] The closed surface is generated by forming nodes through the gaps in the arc surface of the neck of the tumor, and the area of ​​the closed surface is calculated to obtain the area of ​​the arc surface of the neck of the tumor;

[0054] Based on the virtual stent neck arc surface porosity fast algorithm, the neck arc surface porosity is calculated by the neck arc surface porosity area and the neck arc surface area;

[0055] The virtual stent neck arc surface porosity fast algorithm is expressed by the formula:

[0056]

[0057] Among them, K is the porosity of the tumor neck arc surface, S1 is the area of ​​the tumor neck arc surface, and S2 is the porosity area of ​​the tumor neck arc surface.

[0058] The present invention discloses a method for simulating the implantation of a virtual stent for an aneurysm based on a spring analogy method, the method comprising: reconstructing a three-dimensional model of a preoperative tumor-bearing main vessel and a mother vessel after aneurysm restoration based on clinical imaging data; extracting the centerline of the first vessel and constructing a virtual stent initialization model; unfolding the virtual stent initialization model through a spring analogy virtual stent fast algorithm to determine a virtual stent three-dimensional model; and calculating efficacy evaluation parameters through a fast algorithm based on the arc surface porosity of the virtual stent neck. The present invention can simulate the real motion form of stent deployment, and can greatly shorten the simulation calculation time and efficacy evaluation time of simulating the deployment of the stent in the blood vessel, thereby realizing real-time guidance during the virtual intervention of aneurysms. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 A flow chart of a method for simulating aneurysm virtual stent implantation based on a spring analogy method provided by the present invention is shown;

[0060] Figure 2 A flowchart of a method for constructing a virtual support initialization model provided by the present invention is shown;

[0061] Figure 3 A flow chart of a method for deploying a virtual stent initialization model provided by the present invention is shown;

[0062] Figure 4 It shows a schematic structural diagram of a first blood vessel centerline and a second blood vessel centerline provided by the present invention;

[0063] Figure 5A schematic diagram of the local morphological structure of the virtual stent provided by the present invention after it is fully deployed is shown;

[0064] Figure 6 A schematic diagram of the structure of a three-dimensional stent model of a virtual stent in a virtual tumor-bearing blood vessel after full deployment provided by the present invention is shown;

[0065] Figure 7 A schematic diagram of the gap nodes of the arc surface of the tumor neck after projection of the virtual stent wire provided by the present invention is shown. DETAILED DESCRIPTION

[0066] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0067] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0068] Figure 1 A flow chart of an aneurysm virtual stent implantation simulation method based on a spring analogy method provided by the present invention is shown.

[0069] like Figure 1 As shown, the present invention discloses a method for simulating aneurysm virtual stent implantation based on a spring analogy method, comprising:

[0070] S102, obtaining clinical imaging data; the clinical imaging data at least includes the patient's preoperative vascular imaging data;

[0071] S104, based on the analysis of clinical imaging data, reconstructing the three-dimensional model of the preoperative tumor-bearing main vessel and the mother vessel after aneurysm restoration; the three-dimensional model of the preoperative tumor-bearing main vessel and the mother vessel after aneurysm restoration includes the three-dimensional model of the preoperative tumor-bearing main vessel and the three-dimensional model of the mother vessel after aneurysm restoration;

[0072] S106, extracting the centerline of the first blood vessel through the three-dimensional model of the mother blood vessel after aneurysm restoration;

[0073] S108, constructing a virtual stent initialization model based on the centerline of the first blood vessel;

[0074] S110, based on a fast algorithm of a spring analogy virtual support, unfolding the virtual support initialization model to determine a three-dimensional model of the virtual support;

[0075] S112, based on the preoperative three-dimensional model of the tumor-bearing main vessel and the three-dimensional model of the virtual stent, the efficacy evaluation parameters are calculated by a fast algorithm based on the arc surface porosity of the virtual stent neck.

[0076] According to an embodiment of the present invention, the main tumor-bearing vessel is extracted by acquiring clinical imaging data such as the patient's preoperative vascular imaging data from the hospital, reconstructing the preoperative three-dimensional model of the main tumor-bearing vessel, and generating a three-dimensional model of the mother vessel after aneurysm restoration through truncation fitting operations. To ensure the accuracy of the model, the image data may be subjected to image preprocessing such as noise filtering and image enhancement, and the preoperative three-dimensional model of the main tumor-bearing vessel may be meshed reconstructed using the preprocessed image data to reduce the complexity of the model calculation. Then, based on the three-dimensional model of the mother vessel after aneurysm restoration, a centerline model of the blood vessel is generated using a centerline extraction function, and the centerline model file is subjected to data processing to obtain a first blood vessel centerline. The first blood vessel centerline is as follows: Figure 4 As shown in the image on the right. The centerline of the first blood vessel is imported into the reconstructed three-dimensional model of the preoperative tumor-bearing main blood vessel for subsequent use. Among them, the centerline of the first blood vessel is extracted to provide an accurate stent placement path in the subsequent stent implantation simulation, to ensure that the stent contraction length can accurately adapt to the three-dimensional model of the tumor-bearing main blood vessel. Based on the preset initial radius, multiple first nodes are selected on the centerline of the first blood vessel to draw a circle, and multiple second nodes are determined on each circle in a uniformly discrete manner according to the total number of stent wires of the simulated stent. The second nodes on adjacent circles are sorted in positive and negative spirals to construct a virtual stent initialization model. The virtual stent initialization model is expanded based on the internal and external forces perpendicular to the tangent and the tangential force of the stent analogous to the spring. Combined with the distance restriction conditions between the stent nodes, the final placement of the virtual stent is determined to obtain a three-dimensional model of the virtual stent. The fully expanded structure of the three-dimensional model of the virtual stent in the virtual tumor-bearing blood vessel is shown as follows. Figure 6 Its local morphological structure is shown in Figure 5 shown.

[0077] Start the virtual stent neck arc surface porosity fast algorithm, divide the neck plane and obtain its contour position data, determine the point where it intersects with the stent wire, and determine the neck arc surface porosity constituent nodes after the stent wire projection in combination with the preset stent wire diameter. Calculate the neck arc surface porosity by the sum of the mesh area and the polygon area formed by each constituent node to obtain the efficacy evaluation parameter.

[0078] Through the above-mentioned implementation steps, the aneurysm virtual stent technology of the present invention realizes the whole process from image data processing, virtual stent implantation to simulation result analysis. This technology not only improves the accuracy of preoperative planning, but also provides doctors with real-time guidance for virtual surgery, greatly improving the safety and success rate of the operation. The present invention aims to introduce this innovative technology to more medical institutions, promote the overall improvement of aneurysm treatment level, and provide aneurysm patients with more reliable and safer treatment options. The aneurysm virtual stent implantation simulation method based on the spring analogy method provided by the present invention is suitable for various aneurysm virtual stent implantation simulations, including intracranial aneurysms, thoracic aortic aneurysms, abdominal aortic aneurysms, limb aneurysms and visceral artery aneurysms.

[0079] According to an embodiment of the present invention, based on the analysis of clinical imaging data, a three-dimensional model of the preoperative parent vessel and the parent vessel after aneurysm restoration is reconstructed, including:

[0080] By analyzing clinical imaging data, the three-dimensional model of the main tumor-bearing vessels before surgery was reconstructed;

[0081] Preprocess the three-dimensional model of the main tumor-bearing vessels before surgery;

[0082] Generate a second blood vessel centerline based on the preprocessed three-dimensional model of the main tumor-bearing vessel before surgery, truncate the parent blood vessels at both ends of the aneurysm in the preprocessed three-dimensional model of the main tumor-bearing vessel before surgery, fit the centerline segment of the aneurysm area according to the second blood vessel centerline of the parent blood vessels at both ends of the aneurysm, and perform discretization on the centerline segment;

[0083] Obtaining the lumen contour of the parent vessel end close to the aneurysm;

[0084] The lumen contour is fitted and transitioned through discrete points obtained through discretization processing to obtain a three-dimensional model of the parent blood vessel after aneurysm restoration.

[0085] It should be noted that the patient's intracranial imaging data (such as CT or MRI images) and other clinical imaging data are exported from the hospital's imaging database. After the image of the tumor-bearing main vessel is extracted from the patient's intracranial imaging data, a virtual three-dimensional model of the tumor-bearing main vessel and the mother vessel after aneurysm restoration is reconstructed through 3D. The preprocessing of the preoperative three-dimensional model of the tumor-bearing main vessel includes meshing the preoperative three-dimensional model of the tumor-bearing main vessel, extracting the centerline of the preprocessed three-dimensional model of the tumor-bearing main vessel through the centerline extraction function, and obtaining the centerline of the second vessel. The centerline of the second vessel is as follows: Figure 4 As shown in the image on the left, the centerline segment of the aneurysm region is obtained based on the centerline fitting of the second blood vessel, and discretization is performed on the centerline segment. The lumen contour of the parent blood vessel end close to the aneurysm is overfitted to obtain a three-dimensional model of the parent blood vessel after the aneurysm is restored.

[0086] The lumen contour of the parent vessel end close to the aneurysm is obtained through the pre-processed three-dimensional model of the main tumor-bearing vessel before surgery.

[0087] According to an embodiment of the present invention, preprocessing the three-dimensional model of the tumor-bearing main blood vessel before surgery includes:

[0088] Reconstruct the mesh of the three-dimensional model of the main tumor-bearing vessels before surgery;

[0089] The triangular mesh of the reconstructed three-dimensional model of the main tumor-bearing blood vessels before surgery is converted into a Simplex mesh.

[0090] It should be noted that the quality and resolution of image data directly affect the accuracy of the 3D model. Therefore, it is necessary to preprocess the image, such as noise filtering and image enhancement, to ensure the accuracy of the reconstructed model.

[0091] The pre-operative tumor-bearing main vessel 3D model is reconstructed by using the pre-processed impact data. The model is optimized by mesh processing, including denoising, smoothing and refinement, and then the optimized mesh model is saved. The purpose of mesh optimization is to reduce the computational complexity while maintaining the accuracy of the geometric model so that subsequent simulation calculations are more efficient.

[0092] Using the system conversion algorithm, the triangle mesh of the tumor-bearing blood vessels before surgery is converted into a Simplex mesh through the code, and the converted Simplex mesh model is saved.

[0093] The use of Simplex grid can improve the efficiency and accuracy of simulation calculations, especially when dealing with complex geometric structures and mechanical properties.

[0094] Figure 2 A flowchart of a method for constructing a virtual support initialization model provided by the present invention is shown;

[0095] like Figure 2 As shown, according to an embodiment of the present invention, a virtual stent initialization model is constructed based on the centerline of the first blood vessel, including:

[0096] S202, determining a plurality of first nodes on the center line of the first blood vessel; the number of the first nodes is determined according to the curvature of the stent wire;

[0097] S204, analyzing the centerline of the first blood vessel to determine the tangent direction of each first node on the centerline of the first blood vessel;

[0098] S206, sequentially drawing a circle with a preset initial radius and perpendicular to the corresponding tangent direction with each first node as the center;

[0099] S208, determining the number of second nodes on each circle based on the total number of stent filaments of the virtual stent, and uniformly discretizing the second nodes on each circle; the number of second nodes is determined according to the number of stent filaments;

[0100] S210, constructing a virtual support initialization model by performing forward and reverse spiral sorting on the second nodes on the adjacent circles, and determining the second nodes as support nodes;

[0101] S212, converting the diamond mesh of the virtual support initialization model into a Simplex mesh.

[0102] It should be noted that after completing the mesh conversion of the three-dimensional model of the preoperative tumor-bearing main vessel, the first vessel centerline is imported, an algorithm is written, the tangent direction of each first node on the first vessel centerline is calculated, and a circle perpendicular to the tangential direction is made with each first node of the first vessel centerline as the center, and the preset initial radius of each circle is set. The number of first nodes is determined according to the curvature of the stent wire. The greater the curvature of the stent wire, the more corresponding first nodes. The final number of first nodes is set by a technician in this field according to actual needs. The preset initial radius is the initial radius of the virtual stent. The initial value of the preset initial radius is 0.1 mm, and the technician in this field can adjust it according to actual needs. Because the stent is not subject to external force during the free expansion stage, the setting of the preset initial radius will not affect the simulation of the virtual stent, but it must follow its size limit in the catheter of the blood flow guide device, and the second nodes on the circle are evenly discretized. The number of discrete second nodes depends on the total number of stent wires of the simulated stent, and the stent initialization model grid is constructed by sorting the second nodes in positive and negative spirals.

[0103] In this process, the geometric shape and size changes of the blood vessels need to be considered to ensure that the stent can adapt to the vascular structure of different patients.

[0104] The diamond mesh form of the virtual support initialization model is converted to a Simplex mesh and imported into the support initialization model mesh generated in the above steps. Using the conversion algorithm, the diamond mesh form is converted to a Simplex mesh and the converted Simplex mesh model is saved.

[0105] Simplex mesh can better simulate the stress and deformation of the stent in the blood vessel, thereby improving the accuracy of the simulation.

[0106] Figure 3 A flow chart of a method for deploying a virtual stent initialization model provided by the present invention is shown;

[0107] like Figure 3 As shown, according to an embodiment of the present invention, based on a fast algorithm of a spring analogy virtual support, the virtual support initialization model is expanded to determine a three-dimensional model of the virtual support, including:

[0108] S302, determining the expansion force of the stent itself as the internal force, and determining the resistance encountered by the stent when it expands and contacts the inner wall of the blood vessel as the external force;

[0109] S304, assuming that the stent node is a mass point that follows the laws of physics, setting the mass point mass of the stent node, and obtaining the weight factors of the internal force and the external force through the tensile test of the stent and the tensile test of the intracranial vascular tissue; the weight factors of the internal force and the external force are used to determine the proportion of the internal force and the external force on the stent node;

[0110] S306, iteratively expanding the virtual support based on the motion trajectory and internal and external forces of the support node, when the internal and external forces of the support node reach a balanced state, the expansion of the support node in the direction perpendicular to the tangent line is terminated accordingly;

[0111] S308, assuming that the deployment of the stent is the overall movement of multiple positive and negative helical springs of the same material and model, and determining the moment and axial force exerted on a single stent wire through mechanical analysis of the physical stent;

[0112] S310, analogizing the stent to a spring, conducting a spring mechanical property experiment of the stent and a single stent wire, and calculating the bending moment and torque of the micro-element stent wire by the micro-element method;

[0113] S312, applying the bending moment and torque of the micro-element stent wire to the stent nodes of the virtual stent in the form of force to determine the stent tangential force;

[0114] S314, the virtual stent is unfolded by using internal and external forces perpendicular to the tangential direction and the stent tangential force analogous to the spring to determine the three-dimensional model of the virtual stent.

[0115] It should be noted that the formula used to describe the movement of the grid nodes under the action of force is divided into internal and external forces perpendicular to the tangential direction and the tangential force of the stent analogous to a spring. The stent is in a compressed state when it is placed, so the stent itself has an expansion force (internal force). The resistance encountered when the expansion reaches the inner wall of the blood vessel and contacts the inner wall of the blood vessel is called external force. When the internal and external forces reach a balance, the stent stops expanding. The specific implementation is: use mechanical formulas to describe the movement of the grid nodes under the action of internal and external forces, simulate the initial expansion process of the stent point under the action of internal force, and determine whether the stent point contacts the blood vessel wall. If so, an external force is introduced. When the internal and external forces are balanced, the stent expansion process is terminated.

[0116] In addition, the mechanical properties of the scaffold material, such as elastic modulus and yield strength, need to be considered to ensure the authenticity of the simulation.

[0117] The deployment of the stent is regarded as the overall movement of multiple positive and negative spiral springs of the same material and model. Through the mechanical analysis of a single stent wire of the physical stent, the in vitro tensile test of the stent and the code calculation, the moment M0 and the tangential force F exerted on the single stent wire can be obtained. Through the microelement method, the bending moment and torque of the intercepted microelement stent wire can be obtained. The above bending moment and torque are applied to the virtual stent node in the form of force as the stent tangential force. The specific implementation is: perform a mechanical analysis on a single stent wire of the physical stent, obtain the parameter data of the moment M0 and the axial force F, use the microelement method to calculate the bending moment and torque of the intercepted microelement stent wire, apply the bending moment and torque in the form of force to the stent node of the virtual stent, determine the stent tangential force, set the distance from the stent node to the end point of the center line as a multiple of the stent tangential force, and adjust the multiple ratio according to clinical data.

[0118] During this process, a large amount of experiments and data analysis are required to ensure the accuracy and reliability of the model parameters.

[0119] According to an embodiment of the present invention, it also includes:

[0120] The multiple ratio of the bracket tangential force is determined according to the distance from the bracket node to the end point of the center line, and the bracket tangential force is adjusted.

[0121] It should be noted that the centerline end point is the first node corresponding to the stent node on the centerline of the first blood vessel. The distance from the stent node to the centerline end point is a multiple of the stent tangential force of the current stent node. The multiple ratio is set according to the clinical stent deployment length data. When the stent contracts, the force on the stent node is related to the distance from it to the centerline end point.

[0122] According to an embodiment of the present invention, the virtual support is iteratively expanded based on the motion trajectory and internal and external forces of the support node. When the internal and external forces of the support node reach a balanced state, the expansion of the support node in the direction perpendicular to the tangent line is terminated accordingly, including:

[0123] Stent deployment includes two stages: the non-wall-touching stage and the wall-touching stage.

[0124] After each iterative expansion, the distance between the current position of the stent node and the position of the nearest Simplex grid node of the main tumor-bearing vessel before surgery is calculated;

[0125] When the distance is greater than or equal to the preset distance threshold, the expansion of the support node is in the stage of not touching the wall, and the support node expands outwards under the action of internal force;

[0126] When the distance is less than the preset distance threshold, the expansion of the support node enters the wall-touching stage, and the support node expands outward under the combined action of internal and external forces;

[0127] When the internal force is balanced with the external force, the stent node stops expanding.

[0128] It should be noted that in the non-touching the wall stage, the stent nodes only expand outward under the action of internal forces. It is necessary to calculate the distance between the current position of each stent node and the position of the nearest Simplex grid node of the main tumor-bearing vessel before surgery. When the distance is within the specified threshold, it is considered that the stent is in contact with the blood vessel wall. Among them, the preset distance threshold is set by technical personnel in this field according to actual needs. After the stent point adheres to the wall, it enters the second stage (touching the wall stage). The stent nodes not only expand outward under the action of internal forces, but are also subject to the resistance of the blood vessel wall (external force). When the internal force and the external force are balanced, the stent expansion stops.

[0129] The specific implementation is as follows: simulate the initial expansion process of the stent node under the action of internal force, calculate the distance between the current position of the stent node and the previous iteration position, determine whether the stent node contacts the vessel wall, and if so, introduce external force to enter the second stage simulation. When the internal and external forces are balanced, terminate the stent expansion process.

[0130] The actual mechanical environment of the stent within the blood vessel needs to be considered during the stent deployment phase, including the dynamic effects of blood flow and the biomechanical properties of the blood vessel wall.

[0131] According to an embodiment of the present invention, it also includes:

[0132] The maximum and minimum values ​​of the distance between the nodes of the support when the solid support is only subjected to axial pressure and perpendicular to the axial pressure are set as the distance restriction conditions between the nodes of the support; the distance between the nodes of the support includes the distance between the nodes of the support wires and the distance between the nodes of the support segments;

[0133] When the support nodes of the virtual support meet the distance restriction condition between the support nodes, it is determined that the support nodes reach the equilibrium position;

[0134] When all the stent points reach the equilibrium position, the final placement of the virtual stent is determined.

[0135] It should be noted that, according to the physical stent tensile test, the distances between nodes of the physical stent under different pressure conditions (axial stretching and perpendicular to the axial stretching) are measured, and the measured data are used as constraints to set the maximum and minimum distances between the stent nodes, determine the constraints on the distances between the stent nodes, introduce the constraints on the distances between the stent nodes in the simulation, simulate the stent to reach a equilibrium position under the constraints, and obtain the final implantation situation.

[0136] This step needs to ensure the rationality of the restriction conditions to avoid over-expansion or compression of the stent during actual implantation.

[0137] According to an embodiment of the present invention, based on the preoperative three-dimensional model of the tumor-bearing main vessel and the three-dimensional model of the virtual stent, the efficacy evaluation parameters are calculated by a fast algorithm based on the arc surface porosity of the virtual stent neck, including:

[0138] The efficacy evaluation parameters include at least the arc surface porosity of the tumor neck;

[0139] Divide the tumor neck plane based on the preoperative three-dimensional model of the main tumor-bearing blood vessels to obtain the contour position data of the tumor neck plane;

[0140] Calculate the intersection of the contour position data and the stent wire, and determine the node formed by the arc surface gap of the tumor neck after the stent wire is projected based on the preset stent wire diameter;

[0141] Calculate the sum of the polygonal areas formed by each node to determine the gap area of ​​the arc surface of the neck of the tumor;

[0142] The closed surface is generated by forming nodes through the gaps in the arc surface of the neck of the tumor, and the area of ​​the closed surface is calculated to obtain the arc surface area of ​​the neck of the tumor;

[0143] Based on the fast algorithm of the virtual stent neck arc surface porosity, the neck arc surface porosity is calculated by the neck arc surface porosity area and the neck arc surface area;

[0144] The fast algorithm for the porosity of the virtual stent neck arc surface is expressed as follows:

[0145]

[0146] Among them, K is the porosity of the tumor neck arc surface, S1 is the area of ​​the tumor neck arc surface, and S2 is the porosity area of ​​the tumor neck arc surface.

[0147] It should be noted that if Figure 7 As shown, the tumor neck plane and its contour position data are divided based on the three-dimensional model of the main tumor-bearing blood vessel before surgery, and the contour position data is imported into the virtual stent three-dimensional model for analysis, and the intersection point of the contour position data and the stent wire of the virtual stent is calculated. Combined with the preset stent wire diameter, the node of the tumor neck arc surface porosity after the stent wire is projected is calculated. The porosity of the tumor neck arc surface is calculated by the virtual stent neck arc surface porosity fast algorithm. Among them, the closed surface is the total area of ​​the tumor neck arc surface, and the initial value of the preset stent wire diameter is 0.02mm, which can be adjusted by those skilled in the art according to actual needs.

[0148] The coverage effect of the stent in the tumor neck area is evaluated by the porosity of the virtual stent neck arc surface, so as to determine the success rate and risk of the operation.

[0149] The information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.) and signals (including but not limited to signals transmitted between user terminals and other devices, etc.) involved in this application are all authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards of relevant countries and regions. For example, the "clinical imaging data" involved in this disclosure are all obtained with full authorization.

[0150] The present invention discloses a method for simulating the implantation of a virtual stent for an aneurysm based on a spring analogy method, the method comprising: reconstructing a three-dimensional model of a preoperative tumor-bearing main vessel and a mother vessel after aneurysm restoration based on clinical imaging data; extracting the centerline of the first vessel and constructing a virtual stent initialization model; unfolding the virtual stent initialization model through a spring analogy virtual stent fast algorithm to determine a virtual stent three-dimensional model; and calculating efficacy evaluation parameters through a fast algorithm based on the arc surface porosity of the virtual stent neck. The present invention can simulate the real motion form of stent deployment, and can greatly shorten the simulation calculation time and efficacy evaluation time of simulating the deployment of the stent in the blood vessel, thereby realizing real-time guidance during the virtual intervention of aneurysms.

[0151] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0152] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units; they may be located in one place or distributed on multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0153] In addition, all functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may be separately used as a unit, or two or more units may be integrated into one unit; the above-mentioned integrated units may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0154] Those skilled in the art can understand that: all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiments; and the aforementioned storage medium includes: mobile storage devices, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), disks or optical disks, and other media that can store program codes.

[0155] Alternatively, if the above-mentioned integrated unit of the present invention is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present invention can be essentially or partly reflected in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as mobile storage devices, ROM, RAM, magnetic disks or optical disks.

Claims

1. A method for simulating aneurysm virtual stent implantation based on spring analogy, characterized in that: include: Obtain clinical imaging data; The clinical imaging data at least includes the patient's preoperative vascular imaging data; Reconstructing a three-dimensional model of the preoperative tumor-bearing main vessel and the mother vessel after aneurysm restoration based on the analysis of the clinical imaging data; the three-dimensional model of the preoperative tumor-bearing main vessel and the mother vessel after aneurysm restoration includes a three-dimensional model of the preoperative tumor-bearing main vessel and a three-dimensional model of the mother vessel after aneurysm restoration; Extracting the centerline of the first blood vessel through the three-dimensional model of the parent blood vessel after the aneurysm is restored; Constructing a virtual stent initialization model based on the centerline of the first blood vessel; Based on a fast algorithm of a spring analogy virtual support, the virtual support initialization model is expanded to determine a three-dimensional model of the virtual support; Based on the preoperative three-dimensional model of the tumor-bearing main blood vessel and the three-dimensional model of the virtual stent, analysis is performed, and the efficacy evaluation parameters are calculated by a fast algorithm based on the arc surface porosity of the virtual stent neck.

2. The aneurysm virtual stent implantation simulation method based on spring analogy method according to claim 1, characterized in that: The analysis based on the clinical imaging data to reconstruct the three-dimensional model of the preoperative tumor-bearing main vessel and the aneurysm-restored mother vessel includes: By analyzing the clinical imaging data, a three-dimensional model of the main tumor-bearing blood vessels before surgery is reconstructed; Preprocessing the three-dimensional model of the preoperative tumor-bearing main blood vessel; Generate a second blood vessel centerline based on the preprocessed three-dimensional model of the main tumor-bearing vessel before surgery, truncate the parent blood vessels at both ends of the aneurysm in the preprocessed three-dimensional model of the main tumor-bearing vessel before surgery, fit the centerline segment of the aneurysm area according to the second blood vessel centerline of the parent blood vessels at both ends of the aneurysm, and perform discretization on the centerline segment; Obtaining the lumen contour of the parent vessel end close to the aneurysm; The lumen contour is fitted and transitioned through discrete points obtained through discretization processing to obtain a three-dimensional model of the parent blood vessel after aneurysm restoration.

3. The aneurysm virtual stent implantation simulation method based on spring analogy method according to claim 2, characterized in that: The preprocessing of the three-dimensional model of the preoperative tumor-bearing main blood vessel includes: Reconstructing the mesh of the three-dimensional model of the preoperative tumor-bearing main blood vessel; The triangular mesh of the reconstructed three-dimensional model of the main tumor-bearing blood vessels before surgery is converted into a Simplex mesh.

4. The aneurysm virtual stent implantation simulation method based on spring analogy method according to claim 1, characterized in that: The step of constructing a virtual stent initialization model based on the first blood vessel centerline includes: Determine a plurality of first nodes on the centerline of the first blood vessel; the number of the first nodes is determined according to the curvature of the stent wire; Analyze the centerline of the first blood vessel to determine the tangent direction of each first node on the centerline of the first blood vessel; Sequentially draw a circle with a preset initial radius and perpendicular to the corresponding tangent direction with each first node as the center; Determine the number of second nodes on each circle based on the total number of stent filaments of the virtual stent, and evenly discretize the second nodes on each circle; the number of the second nodes is determined according to the number of stent filaments; A virtual support initialization model is constructed by performing positive and negative spiral sorting on the second nodes on the adjacent circles, and the second nodes are determined as support nodes; The diamond mesh of the virtual support initialization model is converted into a Simplex mesh.

5. The aneurysm virtual stent implantation simulation method based on spring analogy method according to claim 1, characterized in that: The virtual support fast algorithm based on spring analogy is used to expand the virtual support initialization model to determine the virtual support three-dimensional model, including: The expansion force of the stent itself is determined as the internal force, and the resistance encountered by the stent when it expands and contacts the inner wall of the blood vessel is determined as the external force; The stent nodes are assumed to be particles that follow the laws of physics, the mass of the particles of the stent nodes is set, and the weight factors of the internal and external forces are obtained through the tensile test of the stent and the tensile test of the intracranial vascular tissue; the weight factors of the internal and external forces are used to determine the proportion of the internal force to the external force on the stent nodes; Iteratively expand the virtual support based on the motion trajectory and internal and external forces of the support node. When the internal and external forces of the support node reach a balanced state, the expansion of the support node in the direction perpendicular to the tangent line is terminated accordingly. The deployment of the stent is assumed to be the overall movement of multiple positive and negative helical springs of the same material and model. The moment and axial force on a single stent wire are determined through mechanical analysis of the physical stent. The stent is compared to a spring to conduct a spring mechanical property experiment of the stent and a single stent wire, and the bending moment and torque of the micro-element stent wire are calculated by the micro-element method. Applying the bending moment and torque of the micro-element stent wire to the stent nodes of the virtual stent in the form of force to determine the stent tangential force; The virtual stent is unfolded by the internal and external forces perpendicular to the tangential direction and the tangential force of the stent analogous to the spring, and the three-dimensional model of the virtual stent is determined.

6. The aneurysm virtual stent implantation simulation method based on spring analogy method according to claim 5, characterized in that: Also includes: The multiple ratio of the tangential force of the bracket is determined according to the distance from the bracket node to the end point of the center line, and the tangential force of the bracket is adjusted.

7. The aneurysm virtual stent implantation simulation method based on spring analogy method according to claim 5, characterized in that: The virtual support is iteratively expanded based on the motion trajectory and internal and external forces of the support node, and when the internal and external forces of the support node reach a balanced state, the expansion of the support node in a direction perpendicular to the tangent line is terminated accordingly, including: The stent deployment includes two stages; the two stages are the non-wall-touching stage and the wall-touching stage; After each iterative expansion, the distance between the current position of the stent node and the position of the nearest Simplex grid node of the main tumor-bearing vessel before surgery is calculated; When the distance is greater than or equal to a preset distance threshold, the expansion of the support node is in a stage where the support node does not touch the wall, and the support node expands outwards under the action of internal force; When the distance is less than a preset distance threshold, the expansion of the support node enters the wall-touching stage, and the support node expands outward under the combined action of internal and external forces; When the internal force is balanced with the external force, the stent node stops expanding.

8. The aneurysm virtual stent implantation simulation method based on spring analogy method according to claim 1, characterized in that: Also includes: The maximum and minimum values ​​of the distance between the nodes of the stent when the solid stent is only subjected to axial pressure and perpendicular to the axial pressure are set as the distance restriction conditions between the nodes of the stent; the distance between the nodes of the stent includes the distance between the nodes of the stent wires and the distance between the nodes of the stent segments; When the support nodes of the virtual support meet the distance restriction condition between the support nodes, determining that the support nodes reach a balanced position; When all the stent points reach the equilibrium position, the final placement of the virtual stent is determined.

9. The aneurysm virtual stent implantation simulation method based on spring analogy method according to claim 1, characterized in that: The analysis is performed based on the preoperative tumor-bearing main vessel three-dimensional model and the virtual stent three-dimensional model, and the efficacy evaluation parameters are calculated by a fast algorithm based on the arc surface porosity of the virtual stent neck, including: The efficacy evaluation parameters include at least the neck arc surface porosity; Dividing the tumor neck plane based on the preoperative three-dimensional model of the tumor-bearing main blood vessel, and obtaining contour position data of the tumor neck plane; Calculating the intersection of the contour position data and the stent wire, and determining the node formed by the arc surface gap of the tumor neck after the stent wire is projected based on the preset stent wire diameter; Calculate the sum of the polygonal areas formed by each node to determine the gap area of ​​the arc surface of the neck of the tumor; The closed surface is generated by forming nodes through the gaps in the arc surface of the neck of the tumor, and the area of ​​the closed surface is calculated to obtain the area of ​​the arc surface of the neck of the tumor; Based on the virtual stent neck arc surface porosity fast algorithm, the neck arc surface porosity is calculated by the neck arc surface porosity area and the neck arc surface area; The virtual stent neck arc surface porosity fast algorithm is expressed by the formula: Among them, K is the porosity of the tumor neck arc surface, S1 is the area of ​​the tumor neck arc surface, and S2 is the porosity area of ​​the tumor neck arc surface.

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