A method and system for assessing the degree of bronchial stenosis

Abstract

The application discloses a bronchial stenosis degree evaluation method and system, and belongs to the technical field of medical imaging. The method comprises the following steps: combining lung CT image data to construct a three-dimensional lung bronchial model; under the three-dimensional lung bronchial model, a fluid dynamics model of lung tissue is established based on an SPH method to simulate fluid flow before and after surgery, the fluid dynamics and tissue mechanics behavior in the surgical process are simulated by simulating the interaction between airflow and lung tissue; and based on the fluid dynamics and tissue mechanics behavior in the simulated surgical process, a physical-based evaluation index is constructed to evaluate the tracheal stenosis degree. The method is a lung bronchial preoperative planning scheme simulation method based on smooth particle hydrodynamics, and can provide intuitive preoperative planning and surgical simulation for surgeons.

Description

TECHNICAL FIELD

[0001] The application provides a bronchial stenosis degree evaluation method and system, and belongs to the technical field of medical imaging. BACKGROUND

[0002] Bronchial stenosis is a common respiratory disease characterized by partial or complete obstruction of the airway lumen. Traditional methods for evaluating the degree of bronchial stenosis mainly rely on medical imaging examinations (such as CT, MRI) and airway function tests. However, these methods usually only provide static geometric information, and have certain limitations in evaluating the impact of airway stenosis on airflow dynamics and the dynamic changes of airway function before and after surgery.

[0003] SPH (Smooth Particle Hydrodynamics) is a meshless Lagrangian numerical method that has significant advantages in dealing with complex problems such as large deformation and free surface flow. In recent years, the SPH method has been widely applied in the field of biomedical engineering, such as simulating blood flow and tissue deformation. By using the SPH method to simulate bronchial stenosis, detailed information such as velocity field and pressure distribution of airflow in the stenotic airway can be obtained, providing a new way to quantitatively evaluate the degree of airway stenosis.

[0004] Currently, some studies have attempted to use computational fluid dynamics (CFD) methods to simulate respiratory airflow, but this method usually uses finite volume method or finite element method to divide the airway into grids, and then solves the Navier-Stokes equation. However, for complex airway geometry and pathological conditions, the generation and quality control of the grid is a difficult problem. For the simulation of airflow under complex airway anatomy and pathological conditions, there are still certain challenges.

[0005] Finite element analysis (FEA) is also a technique commonly used to simulate the mechanical behavior of tissues by dividing the tissue into a finite number of elements and nodes to simulate the stress and strain distribution of the tissue. However, FEA has limitations in dealing with fluid dynamics problems, especially in simulating complex fluid-structure interaction problems in lung bronchial surgery, its computational efficiency is low, and it is difficult to accurately capture the rapidly changing dynamic process.

[0006] The hybrid approach combining FEA and CFD attempts to simulate the mechanical behavior of tissues using FEA while simultaneously simulating their hydrodynamic behavior using CFD. However, this hybrid approach faces several challenges in practical applications: First, the coupled computation of FEA and CFD is highly complex and requires substantial computational resources; second, the mesh systems of the two methods are mismatched, making data exchange and boundary condition handling difficult; and finally, this hybrid approach struggles to provide real-time updates and cannot offer dynamic feedback during surgery. Summary of the Invention

[0007] To address the limitations of existing technologies, this application proposes a method and system for assessing the degree of bronchial stenosis. This method is based on a simulation method for preoperative planning of bronchial surgery using smooth particle hydrodynamics. By simulating fluid flow before and after surgery, it can more accurately assess the degree of bronchial stenosis and surgical outcomes, providing surgeons with intuitive preoperative planning and surgical simulation.

[0008] To solve the above-mentioned technical problems, the technical solution adopted in this application is as follows:

[0009] In a first aspect, this application provides a method for assessing the degree of bronchial stenosis, including:

[0010] A three-dimensional model of the lung bronchi was constructed by combining lung CT imaging data;

[0011] Based on the SPH method, a fluid dynamics model of lung tissue was established under a three-dimensional lung bronchus model to simulate fluid flow before and after surgery. By simulating the interaction between airflow and lung tissue, the fluid dynamics and tissue mechanical behavior during the operation were simulated.

[0012] Based on the fluid dynamics and tissue mechanics behavior during simulated surgery, a physics-based assessment index is constructed to evaluate the degree of tracheal stenosis.

[0013] As a further improvement of this application, the SPH method includes: in a three-dimensional lung bronchus model, dividing the airflow to be simulated into discrete particles, estimating the physical quantity of each particle through a smooth kernel function, and making it satisfy the overall physical laws, and then iteratively calculating the physical quantity of each particle in each frame so that each particle can perform the corresponding motion.

[0014] As a further improvement to this application, the step of establishing a fluid dynamics model of lung tissue based on the SPH method under a three-dimensional lung bronchial model includes:

[0015] In a three-dimensional lung and bronchial model, airflow is set as the initial parameters for particle radius, boundary conditions, etc.

[0016] The density and pressure of the airflow as particles are calculated using a smooth kernel function;

[0017] Calculate the pressure gradient force, viscous force and gravity force on each particle;

[0018] Update the velocity and position of the particle according to the calculated force;

[0019] Couple the airflow with the airway to calculate the collision feedback force;

[0020] Establish a fluid dynamics model of the lung tissue.

[0021] As a further improvement of the present application, the SPH method is used to establish a fluid dynamics model of the lung tissue, and simulate the fluid flow before and after the operation, which comprises:

[0022] For an airflow particle i, A is expressed in a general form:

[0023]

[0024] Where r ij =r i -r j , r i , r j are the positions of particles i and j, m j is the mass of the adjacent particle j, p j is the density of the adjacent particle j, A(r i ) is the physical quantity required for particle i, and W(r ij , h) is a smoothing kernel function.

[0025] The Poly6 kernel function is used as the smoothing kernel function:

[0026]

[0027] Then, according to the smoothing kernel function, the density, pressure and velocity related accumulation functions of a certain point in the fluid are derived one by one, and the acceleration is derived, so as to simulate the motion trend of the fluid. The force acting on a particle is expressed by the following formula:

[0028]

[0029] Thus, the acceleration of the particle is solved:

[0030]

[0031] In the formula, is the acceleration of particle i, is the other external force on particle i, and represent the pressure and viscous force of the surrounding particles on particle i.

[0032] As a further improvement to this application, the simulation of fluid dynamics and tissue mechanics during surgery by simulating the interaction between airflow and lung tissue includes:

[0033] The solid boundary is modeled using boundary particles, which interact with fluid particles. The coupling between the boundary and the airflow consists of two forces: pressure and friction.

[0034] F solid =F pressure +F friction

[0035] Where F solid F is the net force acting on the particle. pressure F represents the pressure exerted on the particle. friction This represents the frictional force acting on the particle; where pressure is expressed as:

[0036]

[0037] The frictional force acting on a particle is expressed as:

[0038]

[0039] Where μ represents the viscosity coefficient, substituting the formulas for the two forces above, we obtain the formula for the interaction force between the fluid particle and the solid boundary:

[0040]

[0041] In the formula, v rel It is the relative velocity vector between particle i and particle j; It is the gradient of the smooth kernel function W with respect to the position; r i and r j are the position vectors of particles i and j, respectively; h is the support radius of the smooth kernel function, also known as the smooth length;

[0042] In the formula, This represents the summation of the effects of all neighboring particles j on the current particle; m j P j and ρ j denoted as the mass, pressure, and density of the neighboring particle j; μ is the equivalent viscosity parameter.

[0043] By analyzing the interaction forces between fluid particles and solid boundaries, the motion trend of the fluid is obtained. The relevant equations are solved frame by frame to simulate the entire process and solve for the collision feedback force.

[0044] As a further improvement of the present application, the lung tissue-based fluid dynamics model is constructed to build a physics-based evaluation index to evaluate the tracheal stenosis degree, including:

[0045] The Monte Carlo method is used to estimate the overall pressure value upstream and downstream of the stenosis region, i.e. F up and F down ; the calculation process is represented as:

[0046]

[0047] where N is the total number of boundary particles upstream or downstream, i is the number of randomly sampled particles, and |F i | represents the modulus of the total force on the particles;

[0048] Based on the simulated pressure ratio before and after the stenosis, a physics-based evaluation index is built:

[0049] Stenosis degree = F up / F down

[0050] where F up is the pressure of the tracheal wall upstream of the stenosis, and F down is the pressure of the tracheal wall downstream of the stenosis.

[0051] In a second aspect, the present application provides a bronchial stenosis degree evaluation system, including:

[0052] A model construction module is configured to construct a three-dimensional lung bronchial model in combination with lung CT image data;

[0053] A mechanical simulation module is configured to establish a lung tissue-based fluid dynamics model based on the SPH method under the three-dimensional lung bronchial model, simulate fluid flow before and after surgery, simulate fluid dynamics and tissue mechanics behavior during surgery by simulating the interaction of airflow and lung tissue;

[0054] An index construction module is configured to build a physics-based evaluation index to evaluate the tracheal stenosis degree based on the fluid dynamics and tissue mechanics behavior during the simulated surgery.

[0055] In a third aspect, the present application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the bronchial stenosis degree evaluation method.

[0056] In a fourth aspect, the present application provides a computer-readable storage medium, which stores a computer program, wherein the computer program is executed by a processor to implement the bronchial stenosis degree evaluation method.

[0057] In a fifth aspect, the present application provides a computer program product, which comprises computer instructions for instructing a computer to execute the bronchial stenosis degree evaluation method.

[0058] The present application has the following beneficial effects over the prior art:

[0059] The bronchial stenosis degree evaluation method provided by the present application is a meshless calculation method, which is particularly suitable for simulating fluid dynamics and fluid-structure interaction problems. Compared with traditional FEA and CFD, SPH can more naturally handle free surface flow and complex boundary conditions while maintaining high computational efficiency. The present application takes advantage of the SPH method, combines with lung CT image data, constructs a three-dimensional lung bronchial model, and simulates the fluid dynamics and tissue mechanics behavior during the operation, providing intuitive preoperative planning and surgical simulation for surgeons, thereby improving the success rate and safety of the operation. Based on the SPH method, combined with lung CT image data, a three-dimensional lung bronchial model is constructed, and the fluid dynamics and tissue mechanics behavior during the operation are simulated. By simulating the interaction of airflow and lung tissue, a new physical-based evaluation index is constructed to evaluate the degree of bronchial stenosis before and after the implantation of a stent, providing intuitive preoperative planning and surgical simulation for surgeons. BRIEF DESCRIPTION OF DRAWINGS

[0060] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following introduces the drawings of the related technical solutions in the embodiments of the present application or the prior art. It should be understood that the drawings in the following introduction are only for the convenience of clearly describing part of the embodiments of the technical solutions of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0061] Figure 1 A bronchial stenosis degree evaluation method flowchart is provided for the present application;

[0062] Figure 2 A preoperative planning scheme simulation framework for lung bronchial is provided for the present application;

[0063] Figure 3 A complete bronchial modeling schematic diagram is provided;

[0064] Figure 4 A simplified model schematic diagram is provided;

[0065] Figure 5 An SPH algorithm flowchart is provided for the present application;

[0066] Figure 6 A bronchial stenosis site schematic diagram is provided;

[0067] Figure 7 schematic diagram of particle under boundary pressure;

[0068] Figure 8 schematic diagram of SPH method provided in the present application;

[0069] Figure 9 schematic diagram of simulation process;

[0070] Figure 10 a bronchial stenosis degree evaluation device provided in the present application;

[0071] Figure 11 a schematic diagram of an electronic device provided in the present application. DETAILED DESCRIPTION

[0072] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application. For the step numbers in the following embodiments, they are only set for the convenience of explanation and description, and the order between the steps is not limited in any way, and the execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0073] In the description of the present application, the words such as setting, installing, connecting, etc. should be understood broadly, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0074] Related term explanation:

[0075] SPH (Smoothed Particle Hydrodynamics) is a meshless Lagrangian method used to simulate the dynamics of continuous media, such as fluid flow and solid mechanics problems. It simulates fluid behavior by simulating fluid as a series of particles, each particle with mass, velocity, and pressure attributes, and through the interaction between particles.

[0076] Pulmonary CT imaging is a medical imaging technology used to observe the structure and function of the lungs. It can provide detailed images of the lungs, helping doctors diagnose various lung diseases such as pneumonia, tuberculosis, lung cancer, etc.

[0077] CFD (Computational Fluid Dynamics) is the English abbreviation for computational fluid dynamics, which is a method of predicting physical fluid flow by solving control equations using mathematical calculations and computers. CFD technology is widely used in engineering and scientific fields such as aerospace, automotive industry, energy production, etc., for optimization design and performance improvement.

[0078] FEA (Finite Element Analysis) is a numerical analysis method for solving complex structural and mechanical problems. It divides a complex structure into many simple elements (finite elements), and then solves the mechanical behavior of the structure by numerical calculation of these elements. The basic principles and steps of finite element analysis include structure discretization, establishment of nodes and elements, definition of material properties and constraints, establishment of finite element model, application of loads and boundary conditions, solution of mathematical model, and analysis of results.

[0079] Spiky kernel function is a kernel function used in Smoothed Particle Hydrodynamics (SPH), which has special properties in dealing with particle interactions. In the SPH method, the kernel function is used to approximate the interaction between particles, especially for calculating the density and pressure of particles. Spiky kernel function is designed because it can maintain positive values when particles are very close, which helps to avoid instability in calculating pressure gradient.

[0080] In the operation of bronchial stenosis, the evaluation of tracheal stenosis degree is very important for the postoperative effect evaluation of tracheal stent operation, which can provide relevant information to doctors in time. However, simple geometric-based evaluation methods cannot comprehensively reflect the effect of the operation and the difference before and after the operation, therefore, the present application plans to simulate the reaction between the trachea and airflow before and after the stent based on the SPH method, and establish new physical-based evaluation indicators to evaluate the degree of tracheal stenosis, and then judge the effect of the operation.

[0081] The existing technology has significant shortcomings in preoperative planning of pulmonary bronchial surgery, including low computational efficiency of finite element analysis (FEA) and computational fluid dynamics (CFD) methods in dealing with complex fluid-structure interaction problems, difficulty in realizing real-time dynamic simulation, and dependence on grid system leading to loss of accuracy in dealing with complex biological tissues and fluid interfaces, as well as complex data exchange and boundary condition processing, lack of intuitive preoperative planning tools.

[0082] In view of these shortcomings, the first object of the present application is to provide a new simulation tool with high computational efficiency, which can simulate the dynamic changes in the operation process in real time, is not dependent on mesh, simplifies data exchange and boundary condition processing, and provides intuitive preoperative planning, so as to improve the accuracy of operation planning and the success rate of operation.

[0083] As shown in Figure 1 the first object of the present application is to provide a bronchial stenosis evaluation method, comprising:

[0084] S1, combining with the lung CT image data, a three-dimensional lung bronchial model is constructed;

[0085] S2, based on the SPH method, a fluid dynamics model of the lung tissue is established under the three-dimensional lung bronchial model, the fluid flow before and after the operation is simulated, and the fluid dynamics and tissue mechanics behavior in the operation process are simulated by simulating the interaction of airflow and lung tissue;

[0086] S3, based on the fluid dynamics and tissue mechanics behavior in the operation process, a physical-based evaluation index is constructed to evaluate the tracheal stenosis.

[0087] The present application introduces a method based on smooth particle hydrodynamics (SPH) to realize three-dimensional dynamic simulation of lung bronchial surgery, so as to improve the accuracy of preoperative planning and the safety of operation. Through SPH simulation, a physical-based evaluation index is established to more comprehensively reflect the influence of airway stenosis degree on airflow dynamics. For preoperative planning and postoperative evaluation of bronchial stenosis surgery, it has stronger pertinence. Combined with the clinical needs of bronchial stenosis surgery, it is expected to make breakthroughs in the quantitative evaluation of airway stenosis and provide more accurate and reliable decision-making basis for clinicians.

[0088] The SPH method is used in airflow tracheal simulation to realize accurate simulation of fluid-structure interaction in the operation process and establish a new physical-based evaluation index to evaluate the tracheal stenosis, so as to judge the operation effect. Through the algorithm implementation of SPH method in bronchial surgery planning, the visualization display technology of operation simulation, and the new physical-based evaluation index to evaluate the tracheal stenosis.

[0089] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0090] Figure 2 For the simulation framework diagram of lung bronchial preoperative planning scheme, a bronchial stenosis evaluation method based on SPH method comprises the following steps:

[0091] First, a three-dimensional model of the lung bronchus is reconstructed using CT image data. The construction of the three-dimensional lung bronchus model specifically includes:

[0092] Data acquisition: First, key information is extracted from the patient's lung CT image data, noise and artifacts are removed through image preprocessing, and gray scale standardization is performed.

[0093] Three-dimensional modeling: Next, the bronchial region is accurately separated, and a three-dimensional surface model is generated using the Marching Cubes surface reconstruction algorithm, followed by grid smoothing, simplification, and hole repair optimization. Finally, the reconstructed model is compared with the original CT image and quantitative analysis is performed, and manual correction is performed to ensure the accuracy of the model. The model not only contains the geometric shape of the bronchus, but also reflects its internal complex structure.

[0094] The complete bronchial modeling is shown in Figure 3 , which is relatively complex. Considering that too fine a model will affect the calculation efficiency, and the main research is the pressure change before and after the stenosis, the reconstructed model is simplified. The simplified model is shown in Figure 4 .

[0095] Second, a fluid dynamics model of the lung tissue is established based on the SPH method to simulate fluid flow before and after surgery. Specifically, the SPH method is applied to the established three-dimensional lung bronchus model to establish a fluid dynamics model of the lung tissue. The SPH method is a particle-based fluid dynamics simulation method that can well handle complex flow fields and fluid-solid interactions.

[0096] Specifically, the SPH method is applied to the established three-dimensional lung bronchus model to establish a fluid dynamics model of the lung tissue. The SPH method is a particle-based fluid dynamics simulation method that can well handle complex flow fields and fluid-solid interactions.

[0097] Simulation of fluid flow: Using this model, the flow of air in the bronchus before and after surgery is simulated. By adjusting the parameters, the air flow under different stenosis degrees can be simulated.

[0098] Simulation of tissue mechanical behavior: In addition to fluid dynamics simulation, this method also considers the mechanical behavior of the lung tissue. By simulating the deformation and stress distribution of the tissue during the operation, the effectiveness of the operation can be more comprehensively evaluated.

[0099] Among them, the SPH algorithm will divide the fluid to be simulated into discrete particles, estimate the physical quantities of each particle through a smoothing kernel function, and make it satisfy the overall physical law, then through continuous iteration calculation of each particle each frame of physical quantity, make each particle can carry out corresponding movement, finally get the expected result.

[0100] Figure 5For SPH algorithm flowchart, used for calculating fluid dynamics (CFD) or similar simulation, the flow is as follows:

[0101] Step 1. Initialize simulation parameters: set initial parameters such as particle radius, boundary conditions, etc.

[0102] Step 2. Calculate the density and pressure of particles using Poly6 kernel function: this is a mathematical method for calculating the interaction between particles.

[0103] Step 3. Calculate the pressure gradient force, viscous force and gravity experienced by each particle: these forces will affect the motion of the particles.

[0104] Step 4. Update the velocity and position of particles according to the calculated forces: this is the core step in the simulation, which determines the dynamic behavior of the particles.

[0105] Step 5. Calculate the coupling of airflow and airway, solve the collision feedback force: this step may involve the interaction between fluid and solid structure.

[0106] Step 6. Output the corresponding simulation results: finally, the results of the simulation are output for further analysis or use.

[0107] Iterative process is carried out, in which steps 2 to 5 may be repeated until the termination condition of the simulation is reached.

[0108] Based on the above scheme, the specific process of the embodiment is given:

[0109] For a particle i, its physical quantity A can be represented in a general form:

[0110]

[0111] where r ij =r i -r j , r i , r j are the positions of particles i, j, m j is the mass of adjacent particle j, ρ j is the density of adjacent particle j, A(r i ) is the physical quantity of particle i required, W(r ij , h) is the smoothing kernel function.

[0112] Optionally, the poly6 kernel function is used as the smoothing kernel function in the embodiment, and the expression of the poly6 kernel function is as follows:

[0113]

[0114] The density, pressure and velocity related accumulated functions of a certain point in the fluid are then derived according to the smoothing kernel function, and the acceleration at the point is further derived to simulate the motion trend of the fluid. The force acting on a particle can be expressed by the following formula:

[0115]

[0116] The acceleration (rate of change of velocity and direction) of the particle can be solved as follows:

[0117]

[0118] In the formula, is the acceleration of the i-th particle, is the other external force (such as gravity) received by the i-th particle, and represent the pressure and viscous force of the surrounding particles on the i-th particle.

[0119] Optionally, the application models the solid boundary by boundary particles and interacts with the fluid particles. The coupling between the boundary and the airflow can be divided into two forces, one is the pressure between them, and the other is the friction force between them. The former is similar to the calculation method of the pressure inside the fluid, and the latter is similar to the viscous force between the airflow particles.

[0120] F solid = F pressure +F friction (5)

[0121] Where F solid is the resultant force received by the particle, F pressure represents the pressure received by the particle, and F friction represents the friction force received by the particle. The pressure can be represented as:

[0122]

[0123] The friction force received by the particle is represented as:

[0124]

[0125] Where μ represents the viscosity coefficient. Substituting the above two force formulas into the formula, the interaction force formula between the fluid particles and the solid boundary is obtained:

[0126]

[0127] In the formula, v rel is the relative velocity vector between the i-th particle and the j-th particle; is the gradient of the smoothing kernel function W with respect to the position; r i and r jare the position vectors of particle i and particle j, respectively; h is the support radius of the smoothing kernel function, also known as the smoothing length;

[0128] wherein, denotes the summation of the effect of all neighboring particles j on the current particle; m j , P j and p j are the mass, pressure and density of neighboring particle j, respectively; μ is the equivalent viscous parameter;

[0129] Through the above equations, the movement trend of the fluid can be obtained, and the relevant equations are solved frame by frame, and then the entire process is simulated.

[0130] Finally, the simulation results are displayed through visualization technology, and the degree of tracheal stenosis is evaluated through physical-based evaluation indicators, providing a reference for surgical planning. The construction of evaluation indicators specifically includes:

[0131] Physical-based evaluation indicators: based on the fluid dynamics and tissue mechanics behavior during the simulated surgical process, a series of physical-based evaluation indicators are constructed. These indicators can quantify the degree of bronchial stenosis and the impact of surgery on airflow and tissue.

[0132] Comprehensive evaluation: by comprehensively analyzing these evaluation indicators, the degree of bronchial stenosis can be more accurately evaluated, and strong support can be provided for the formulation of surgical plans.

[0133] Figure 6 The figure shows the tracheal stenosis site; traditional tracheal stenosis evaluation methods are usually based on area calculation, and common calculation methods are:

[0134]

[0135] However, purely geometric-based calculations can have errors, and it is difficult to select the corresponding cross-section, therefore, the present application refers to the coronary stenosis degree judgment standard to set up a similar index for calculation. Figure 7 The figure shows the boundary pressure on the particle.

[0136] The present application uses the Monte Carlo method to estimate the overall pressure values upstream and downstream of the stenosis region, i.e. up and F down

[0137] The calculation can be represented as:

[0138]

[0139] where N is the total number of boundary particles upstream or downstream, i is the number of randomly sampled particles, and |F i | represents the modulus of the total force on the particle.

[0140] Figure 8 The simulation diagram for the SPH method; the method selected in this application is based on the simulation of the pressure ratio before and after the stenosis, and the calculation method can be represented as:

[0141] Stenosis degree = F up / F down (11)

[0142] Where F up is the pressure of the tracheal wall upstream of the stenosis, and F down is the pressure of the tracheal wall downstream of the stenosis.

[0143] By simulating the interaction between airflow and lung tissue, a new physical-based evaluation index is constructed to evaluate the degree of tracheal stenosis before and after the implantation of a stent, as shown in Figure 9 , which can realize the simulation process and provide surgeons with intuitive preoperative planning and surgical simulation.

[0144] Further, the above simulation process is based on physical principles and has a solid theoretical basis, which makes the simulation results more reliable and can provide strong support for surgical planning. By constructing a series of physical-based evaluation indexes, the degree of bronchial stenosis can be more accurately evaluated. These indexes can quantify the impact of surgery on airflow and tissue, providing strong support for the development of surgical plans. This scheme uses particle methods to simulate fluid motion and evaluates the degree of tracheal stenosis through visualization techniques and physical-based evaluation indexes. This method has the advantages of high precision, flexibility, visualization, physical basis, and comprehensive evaluation, and can provide strong support for surgical planning.

[0145] Compared with the FEA-based method, the SPH method used in this application has higher computational efficiency and better simulation accuracy when dealing with fluid-structure interaction problems. In addition, this application can provide more intuitive surgical simulation and preoperative planning, which helps to improve the success rate and safety of surgery. Therefore, this application has the following advantages:

[0146] High precision: through the combination of three-dimensional modeling and SPH method, high-precision simulation and evaluation of bronchial stenosis can be achieved.

[0147] Comprehensiveness: not only considers the flow of airflow in the bronchus, but also considers the mechanical behavior of lung tissue, making the evaluation results more comprehensive and accurate.

[0148] Practicality: this method can provide doctors with intuitive prediction of surgical effects, which helps to develop more reasonable surgical plans and reduce surgical risks.

[0149] As Figure 10 shown, the third object of the present application is to provide a bronchial stenosis evaluation system, comprising:

[0150] a model construction module 100, configured to construct a three-dimensional lung bronchus model in combination with lung CT image data;

[0151] a mechanical simulation module 200, configured to establish a fluid dynamics model of lung tissue based on an SPH method under the three-dimensional lung bronchus model, simulate fluid flow before and after surgery, simulate fluid dynamics and tissue mechanics behavior in the surgical process by simulating the interaction of air flow and lung tissue;

[0152] an index construction module 300, configured to construct a physics-based evaluation index to evaluate the degree of tracheal stenosis based on the fluid dynamics and tissue mechanics behavior in the simulated surgical process.

[0153] The bronchial stenosis evaluation system of the present application is based on the above-mentioned bronchial stenosis evaluation method.

[0154] As shown in Figure 11 the third object of the present application is to provide an electronic device, which includes a memory 701, a processor 702, and a computer program stored in the memory 701 and executable on the processor, and the processor implements the above-mentioned bronchial stenosis evaluation method when executing the computer program. It also includes a communication interface 703 and a bus 704.

[0155] The fourth object of the present application is to provide a computer-readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the above-mentioned bronchial stenosis evaluation method.

[0156] The fifth object of the present application is to provide a computer program product, which includes computer instructions, and the computer instructions instruct a computer to execute the above-mentioned bronchial stenosis evaluation method.

[0157] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including instruction devices, which implement the functions specified in the flow Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0158] These computer program instructions can also be loaded into a computer or other programmable data processing device, so that a series of operation steps are performed on the computer or other programmable device to produce a computer-implemented process, and the instructions executed on the computer or other programmable device provide a product for implementing the functions specified in the flow Figure 1 one flow or multiple flows and / or blocks Figure 1steps of a function specified in one or more blocks.

[0159] The present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment containing both software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, RAM, ROM, optically readable storage media (e.g., CD-ROM), etc.) embodying computer-readable program code.

[0160] The present application is described in terms of flowcharts and / or block diagrams, which can illustrate the operating of the methods, apparatus (systems), and computer program products according to embodiments of the present application. It will be understood that each block of the flowchart and / or block diagrams, and combinations of blocks in the flowchart and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processing element or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions of the flowchart and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus for performing the functions specified in one or more blocks.

[0161] Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work should fall within the protection scope of the present application.

[0162] Finally, it should be noted that the above embodiments are merely used to illustrate, but not limit the technical solutions of the present application. Although the present application has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that the specific implementation of the present application can be modified or replaced, and any modification or replacement without departing from the spirit and scope of the present application should be covered within the protection scope of the claims of the present application.

Claims

1. A method of assessing the degree of bronchial stenosis, characterized by, The application relates to a method for evaluating the degree of tracheal stenosis, and a system thereof. The method comprises the following steps: combining lung CT image data to construct a three-dimensional lung bronchial model; under the three-dimensional lung bronchial model, a fluid dynamics model of lung tissue is established based on an SPH method to simulate fluid flow before and after surgery, the fluid dynamics and tissue mechanics behavior in the surgical process are simulated by simulating the interaction between airflow and lung tissue, and a physical-based evaluation index is constructed based on the fluid dynamics and tissue mechanics behavior in the surgical process to evaluate the degree of tracheal stenosis. The SPH method comprises the following steps: under the three-dimensional lung bronchial model, airflow to be simulated is divided into discrete particles, the physical quantity of each particle is estimated by a smoothing kernel function, and the whole physical law is met, then the physical quantity of each particle in each frame is calculated by continuous iteration, and each particle can move correspondingly. The method for establishing the fluid dynamics model of lung tissue based on the SPH method under the three-dimensional lung bronchial model comprises the following steps: under the three-dimensional lung bronchial model, initial parameters such as the radius of airflow as particles and boundary conditions are set; the density and pressure of airflow as particles are calculated by using a smoothing kernel function; the pressure gradient force, viscous force and gravity of each particle are calculated; the velocity and position of each particle are updated according to the calculated force; airflow and the trachea are coupled to calculate the collision feedback force; and the fluid dynamics model of lung tissue is established. The method for simulating the fluid dynamics and tissue mechanics behavior in the surgical process by simulating the interaction between airflow and lung tissue comprises the following steps: a solid boundary is modeled by a boundary particle and interacts with fluid particles, the coupling between the boundary and airflow is divided into two forces, one is the pressure between the two, and the other is the friction between the two; the friction force borne by the particle is represented as follows: wherein mu represents a viscosity coefficient; the formula of the above two forces is substituted to obtain the formula of the interaction force between the fluid particle and the solid boundary; the motion trend of the fluid is obtained through the interaction force between the fluid particle and the solid boundary, relevant equations are solved frame by frame, and the whole process is simulated to solve the collision feedback force. The method for establishing the fluid dynamics model of lung tissue based on the SPH method to simulate fluid flow before and after surgery comprises the following steps: for an airflow particle i, A is represented in a general form; a Spiky kernel function is adopted as the smoothing kernel function; then the density, pressure and velocity related accumulation functions of a certain point in the fluid are sequentially derived according to the smoothing kernel function, and the acceleration is derived, so that the motion trend of the fluid is simulated, and the force acting on a particle is expressed by the following formula: wherein rho represents the density of the particle, p represents the pressure of the particle, xi represents the position of the particle, xi represents the position of the particle, xi represents the position of the particle, xi represents the position of the particle, xi represents the position of the particle, xi represents the position of the particle, xi 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the smooth kernel function; where denotes the summation over all neighboring particles j of the current particle; m j , P j and p j are the mass, pressure and density of neighboring particle j, respectively; μ is the equivalent viscous parameter; ​ 2. The method of assessing the degree of bronchial stenosis according to claim 1, wherein, ​ ​ Where r ij =r i -r j r i r j Let m be the position of particles i and j respectively. j Let ρ be the mass of the neighboring particle j. j Let A(r) be the density of neighboring particle j. i Let W(r) be the physical quantity of particle i that needs to be obtained. ij h) is the smooth kernel function; ​ ​ ​ where is the acceleration of the i particle, is other external forces experienced by the i particle, and represents the pressure and viscous forces of surrounding particles on the i particle.

3. The method of assessing the degree of bronchial stenosis according to claim 1, wherein, ​ The overall pressure values upstream and downstream of the stenosis region are estimated using the Monte Carlo method, i.e. F up and F down ; the calculation process is represented by: where N is the total number of particles at the upstream or downstream boundary, i is the number of randomly sampled particles, |F| is the modulus of the total force on the particles. i | represents the modulus of the total force on the particles. ​ Narrowing degree = F up / F down where F up is the pressure of the narrow upstream airway wall, F down is the pressure of the narrow downstream airway wall.

4. A bronchial stenosis degree evaluation system based on the bronchial stenosis degree evaluation method according to any one of claims 1 to 3, characterized by, ​ ​ The mechanical simulation module is configured to simulate fluid flow before and after the surgery based on a fluid dynamics model of lung tissue established based on an SPH method under a three-dimensional lung bronchus model, simulate interaction between airflow and lung tissue, and simulate fluid dynamics and tissue mechanics behavior in the surgery process. The index construction module is configured to construct a physics-based evaluation index based on the fluid dynamics and tissue mechanics behavior in the simulation of the surgery process to evaluate the tracheal stenosis degree.

5. An electronic device, comprising: The computer readable storage medium stores a computer program, and the computer program is executed by the processor to implement the tracheal stenosis degree evaluation method in any one of claims 1-3.

6. A computer readable storage medium characterized by The computer readable storage medium stores a computer program, and the computer program is executed by the processor to implement the tracheal stenosis degree evaluation method in any one of claims 1-3.

7. A computer program product comprising computer instructions, characterized in that, The computer instructions instruct the computer to execute the tracheal stenosis degree evaluation method in any one of claims 1-3.

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