Method and system for constructing bicoscopic myocardial fiber structure and myocardial main power model thereof

Abstract

The invention provides a bi-observation myocardial fiber structure and a construction method and system of a myocardial main power model thereof, and belongs to the technical field of biomechanics and computer simulation. Comprising the following steps: constructing macroscopic distribution of a cardiac muscle fiber structure in cardiac muscle based on a regular fiber generation method; constructing microcosmic distribution of a cardiac muscle fiber structure in the cardiac muscle based on a probability density function; and constructing a myocardial active mechanical model of the myocardial fiber structure according to the macroscopic distribution and microcosmic distribution of the built cardiac muscle fiber structure in the myocardial. According to the method, the dispersity and directivity of the fibers and multi-dimensional distribution of active stress are combined, the accuracy of heart mechanical simulation can be effectively improved, and then scientific guidance is provided for diagnosis and treatment of heart diseases.

Description

Technical Field

[0001] The present invention belongs to the field of biomechanics and computer simulation technology, and in particular relates to a method and system for constructing a dual-view myocardial fiber structure and a myocardial main force model thereof. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Myocardial fibers are the primary constituent tissue of the myocardium, and their contractile mechanical behavior is the basis of cardiac contractile function. Traditional cardiac biomechanical models focus primarily on the overall behavior of myocardial fibers and the overall contractile mechanics of the heart, but often overlook the distribution of myocardial fibers in different directions and the influence of active stress. As research deepens, increasing evidence indicates that the dispersion and directionality of myocardial fibers, as well as their active stress distribution in different directions, play a key role in the contractile behavior of the heart. Therefore, how to accurately simulate the distribution and structure of myocardial fibers, especially the dispersion and directionality of the fibers, is an important challenge in cardiac biomechanics research.

[0004] Traditional myocardial mechanics models often employ simplifying assumptions, such as treating myocardial fibers as one-dimensional straight bundles or uniformly arranged structures. These models typically overlook the complexity of the relative positions and distributions of the fibers. Therefore, while these models can describe the basic contraction process of the heart, they fail to account for the dispersion of fibers in actual myocardial tissue, active stresses in different directions, and heterogeneity between fibers. This simplification leads to discrepancies between model calculations and actual physiological conditions, significantly limiting the model's predictive accuracy, particularly when dealing with cardiac pathology and individual variability. Summary of the Invention

[0005] To overcome the deficiencies of the above-mentioned prior art, the present invention provides a method and system for constructing a dual-view myocardial fiber structure and its myocardial active force model. Combining the dispersion, directionality and multi-dimensional distribution of fiber active stress, it can effectively improve the accuracy of cardiac mechanical simulation, thereby providing scientific guidance for the diagnosis and treatment of heart diseases.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0007] The first aspect of the present invention provides a method for constructing a dual-view myocardial fiber structure and a myocardial main force model thereof.

[0008] The method for constructing a dual-view myocardial fiber structure and myocardial main force model includes:

[0009] A rule-based fiber generation method was used to construct the macroscopic distribution of myocardial fiber structure within the myocardium. Specifically, boundary conditions were set for the ventricular model, and Poisson's equation was used for interpolation calculation to determine the normalized thickness interpolation at the myocardial thickness. Subsequently, a fiber axis coordinate system was constructed within each finite element.

[0010] The microscopic distribution of myocardial fiber structure in the myocardium is constructed based on the probability density function. Specifically, the probability density function is used to characterize the dispersed fibers in the finite element unit, and the microscopic distribution of myocardial fibers in the myocardium is constructed according to the divergence degree of the dispersed fibers.

[0011] According to the macroscopic distribution and microscopic distribution of the myocardial fiber structure in the constructed myocardium, a myocardial main dynamics model of the myocardial fiber structure is constructed.

[0012] Furthermore, boundary conditions are set for the ventricular model; wherein the boundary conditions include initial values of all endocardial surface points and epicardial surface points in the ventricle.

[0013] Furthermore, the Poisson equation is used for interpolation calculation to obtain the interpolation value and corresponding gradient direction of each point inside the myocardium; then, the obtained gradient direction is normalized to obtain a unit vector along the wall, and the obtained unit vector is perpendicular to the myocardial wall from the inside to the outside.

[0014] Furthermore, a fiber axis coordinate system is constructed within each finite element unit, including: determining the longitudinal direction of the ventricle based on the geometric characteristics of the ventricle, determining the radial direction of the ventricle based on the longitudinal direction and the unit vector along the wall obtained by unitization, and multiplying the longitudinal direction by the radial direction to determine the circumferential direction of the ventricle; and constructing local direction coordinates according to the determined longitudinal direction, radial direction and circumferential direction of the ventricle.

[0015] Furthermore, the fiber angle value is assigned to each finite element in combination with the linear change of the angle from the outside of the membrane to the inside of the membrane to construct the fiber axis coordinate system.

[0016] Furthermore, the probability density function is characterized by a dispersion function of in-plane muscle fibers and a dispersion function of out-of-plane muscle fibers.

[0017] Furthermore, the myocardial main dynamics model is:

[0018]

[0019] Among them, T a Indicates the active force value, n f 、n s and n n They represent the distribution ratio of the active force value in the three axis directions of the fiber axis coordinate system, σ a represents the optimized myocardial active force model, The unit vector representing the direction of the initial myocardial fiber deformation under the action of the main force, represents the unit vector after deformation in the initial transmural direction, The unit vector that represents the deformation of the initial direction perpendicular to the fiber and transmural plane.

[0020] The second aspect of the present invention provides a system for constructing a dual-view myocardial fiber structure and a myocardial main force model thereof.

[0021] The system for constructing a dual-view myocardial fiber structure and myocardial active force model includes:

[0022] The macroscopic distribution module is configured to: construct the macroscopic distribution of myocardial fiber structure in the myocardium based on a rule-based fiber generation method, specifically: set boundary conditions for the ventricular model and use Poisson's equation to perform interpolation calculations to determine the normalized thickness interpolation at the myocardial thickness; then, construct a fiber axis coordinate system within each finite element;

[0023] The microscopic distribution module is configured to: construct the microscopic distribution of myocardial fiber structure in the myocardium based on the probability density function, specifically: use the probability density function to characterize the dispersed fibers in the finite element unit, and construct the microscopic distribution of myocardial fibers in the myocardium according to the divergence degree of the dispersed fibers;

[0024] The myocardial main dynamics model construction module is configured to construct a myocardial main dynamics model of the myocardial fiber structure according to the macroscopic distribution and microscopic distribution of the myocardial fiber structure in the constructed myocardium.

[0025] The third aspect of the present invention provides a computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements the steps in the method for constructing a dual-view myocardial fiber structure and a myocardial active force model thereof as described in the first aspect of the present invention.

[0026] The fourth aspect of the present invention provides an electronic device, including a memory, a processor, and a program stored in the memory and runnable on the processor. When the processor executes the program, it implements the steps in the method for constructing a dual-view myocardial fiber structure and its myocardial main force model as described in the first aspect of the present invention.

[0027] One or more of the above technical solutions have the following beneficial effects:

[0028] The present invention determines the direction and distribution of myocardial fibers by adopting a rule-based fiber generation method. This method combines the normalized thickness interpolation at the myocardial thickness and the linear change of the angle from the outside of the membrane to the inside of the membrane to assign an accurate fiber angle value to each unit, and defines the fiber rotation angle by establishing a fiber axis coordinate system and a local coordinate system, so as to more realistically reflect the distribution of myocardial fibers. In addition, the present invention takes into account the dispersion of muscle fibers, especially the difference in the distribution of muscle fibers in the plane and out of the plane, and adopts a dispersed active stress model to consider the influence of fiber direction and distribution when calculating contractile force. This method significantly improves the accuracy of the cardiac mechanics model by introducing the probability density function and structural tensor model of fiber dispersion, and has important application value in the research and treatment of heart diseases.

[0029] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0031] Figure 1 Flowchart of the method for constructing a dual-view myocardial fiber structure and myocardial main force model in Example 1 of the present invention.

[0032] Figure 2 Schematic diagram of the boundary condition setting of the left ventricle and the calculation of the Poisson equation in the first embodiment of the present invention.

[0033] Figure 3 Schematic diagram of the local coordinate system and fiber axis coordinate system of the left ventricle in Example 1 of the present invention.

[0034] Figure 4 Schematic diagram of the macroscopic distribution of myocardial fiber structure in Example 1 of the present invention.

[0035] Figure 5 Schematic diagram of the microscopic distribution of myocardial fiber structure in Example 1 of the present invention.

[0036] Figure 6 Schematic diagram of the effect of different myocardial fiber macro-transmural rotation angles on contractile function in Example 1 of the present invention.

[0037] Figure 7 Schematic diagram of the effect of different myocardial fiber microscopic divergence degrees on contractile function in Example 1 of the present invention. DETAILED DESCRIPTION

[0038] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0039] It should be noted that the terms used herein are for describing particular embodiments only and are not intended to limit the exemplary embodiments according to the present invention.

[0040] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0041] Example 1

[0042] This embodiment discloses a method for constructing a dual-view myocardial fiber structure and a myocardial main force model.

[0043] like Figure 1 As shown, the method for constructing a dual-view myocardial fiber structure and myocardial active force model includes:

[0044] Step S1: constructing the macroscopic distribution of myocardial fiber structure in the myocardium based on a rule-based fiber generation method. Specifically, boundary conditions are set for the ventricular model, and Poisson's equation is used for interpolation calculation to determine the normalized thickness interpolation at the myocardial thickness; then, a fiber axis coordinate system is constructed within each finite element;

[0045] Step S2: constructing the microscopic distribution of myocardial fiber structure in the myocardium based on the probability density function. Specifically, the probability density function is used to characterize the dispersed fibers in the finite element unit, and the microscopic distribution of myocardial fibers in the myocardium is constructed according to the divergence degree of the dispersed fibers.

[0046] Step S3: constructing a myocardial main dynamics model of the myocardial fiber structure according to the macroscopic distribution and microscopic distribution of the myocardial fiber structure in the constructed myocardium.

[0047] The purpose of the present invention is to provide a more accurate myocardial fiber structure modeling method, which can comprehensively consider the influence of fiber dispersion, directionality and inter-fiber interaction, and will help to improve the accuracy and applicability of cardiac mechanics models. Based on the above process, the present invention combines the dispersion, directionality and multi-dimensional distribution of active stress of fibers, which can effectively improve the accuracy of cardiac mechanics simulation, and thus provide scientific guidance for the diagnosis and treatment of heart disease. In order to facilitate the understanding of the technical solution of the present invention, the specific implementation steps of the technical solution of the present invention are further explained and illustrated below. It should be noted that the following embodiments are explained based on a left ventricular model, and the left ventricular model can use the left ventricular finite element model published in a public database.

[0048] In step S1, a rule-based fiber generation method is used to construct the macroscopic distribution of myocardial fiber structure within the myocardium, i.e., to determine the three-dimensional spatial orientation of myocardial fibers at different thickness locations. The macroscopic distribution of myocardial fiber structure is at the millimeter scale, and the construction process includes:

[0049] ① Determine the normalized thickness interpolation at the myocardial thickness

[0050] Set boundary conditions for the left ventricle model; the boundary conditions include initial values of all endocardial surface points and epicardial surface points in the ventricle.

[0051] As an optional embodiment, when setting boundary conditions for the left ventricle model, the initial values of all endocardial surface points of the left ventricle can be set to 0, and the initial values of all epicardial surface points can be set to 1. This setting directly obtains the normalized myocardial thickness position, that is, the relative thickness position e∈[0,1] of the myocardial node, which facilitates the subsequent definition of the rotation angle of the myocardial fiber at the thickness of each unit.

[0052] ②Use Poisson equation for interpolation calculation

[0053] Poisson's equation is used for interpolation calculations to obtain the interpolated value u and the corresponding gradient direction Du for each point within the myocardium. The resulting gradient direction Du is then normalized to obtain a transmural unit vector s0, which is perpendicular to the myocardial wall from the inside out. e represents the relative thickness of the myocardial wall at the point. If e is close to 0, the point is close to the endocardium; otherwise, it is close to the epicardium.

[0054] like Figure 2 Shown is the left ventricular geometric model for normalized thickness interpolation at the location where myocardial thickness is determined and for interpolation calculations using the Poisson equation. The boundary conditions for the endocardial surface are set to 0 (blue), and those for the epicardial surface are set to 1 (red). The internal gradient indicates the interpolation calculated using the Poisson equation, and the arrows indicate the transmural direction.

[0055] ③Construct the fiber axis coordinate system in each finite element

[0056] The longitudinal direction of the ventricle is determined based on the geometric characteristics of the ventricle, the radial direction of the ventricle is determined based on the longitudinal direction and the unit vector along the wall obtained by unitization, and the circumferential direction of the ventricle is determined by multiplying the longitudinal direction and the radial direction; local direction coordinates are constructed according to the determined longitudinal direction, radial direction and circumferential direction of the ventricle.

[0057] As an optional embodiment, a tetrahedral mesh can be used, that is, a finite element unit is composed of four spatial points. The position and transmural direction of the center of a single finite element unit are obtained by taking the mean of the interpolated value u and the unit vector s0 of the four unit points. First, the long axis direction of the left ventricle can be determined from the left ventricular geometric characteristics, that is, the direction from the apex to the center of the mitral valve, which is recorded as the longitudinal direction w l ; Next, the unit vector s0 and the longitudinal direction w l By performing vector interpolation calculation, the radial direction of the left ventricle can be obtained, which is recorded as w r =w l ×s0; then, by dividing the obtained longitudinal direction w l With radial direction w r Multiply to continue calculating the circumferential direction w c =w l ×w r Finally, ensure that the circumferential direction w c , radial direction w r and the longitudinal direction w l After normalization, the local coordinate system at the center of each finite element is obtained, that is, w c -w r -w l The local coordinate system at the center of the finite element is obtained as Figure 3 shown.

[0058] On this basis, the fiber angle value is assigned to each finite element in combination with the linear change of the angle from the outside to the inside of the membrane to construct the fiber axis coordinate system. When constructing the fiber axis coordinate system, it can be achieved through the following methods.

[0059] First, it is assumed that myocardial fibers are distributed in a spiral pattern from the endocardium to the epicardium, and the rotation angle is linearly related to the normalized thickness. c -w r -w l ) in the circumferential direction w c and vertical w l In the plane formed, relative to the circumferential direction w c , the myocardial fiber direction angle on the endocardial surface is α, and the myocardial fiber direction angle on the epicardial surface is β; then, the fiber angle θ = (β-α) × e + α in each unit of the myocardium corresponds to the fiber direction and can be expressed as:

[0060] f0=w l ×sinθ+w c ×cosθ;

[0061] Among them, f0 represents the average direction of countless tiny divergent fibers in the unit space. Figure 4The figure shows the distribution structure of myocardial fibers f0 in the entire left ventricle, i.e. the spatial macroscopic distribution diagram of myocardial fibers. Figure 4 In the figure, fibers with similar positions and directions are linked into a linear display to facilitate observation of the rotation distribution from the inside out; different colors represent different rotation angles. Specifically, colors close to red represent angles α close to the endocardial surface, and colors close to blue represent angles β close to the epicardial surface.

[0062] Then, interpolation calculation is performed to obtain n0=f0×s0, and (f0-s0-n0) is used to form the fiber axis coordinate system for the calculation of the main force in the subsequent process. Among them, n0 represents the vertical direction of the plane formed by the fiber direction and the transmural direction. The fiber axis coordinate system at the center of the obtained finite element unit is as follows Figure 3 shown.

[0063] In step S2, the microscopic distribution of myocardial fiber structure within the myocardium is constructed based on the probability density function. From a microscopic scale, each finite element unit space is composed of countless tiny myocardial fibers, which are not completely arranged in a single direction but are dispersed. The microscopic distribution of myocardial fiber structure is at the micrometer scale, and its construction process includes:

[0064] First, for any finite element unit space, it is assumed that the dispersed fibers at any position can be represented by the probability density function ρ(Θ, b1, Φ, b2), and further assumed that the probability density function ρ(Θ, b1, Φ, b2) is composed of two independent functions ρ in (Θ,b1) and ρ out (Φ, b2), that is, the probability density function is characterized by the dispersion function of the muscle fibers in the plane and the dispersion function of the muscle fibers out of the plane. Specifically, for the dispersed muscle fibers around f0, there are:

[0065] ρ(Θ,b1,Φ,b2)=Gρ in (Θ,b1)ρ out (Φ,b2);

[0066] Among them, ρ in (Θ,b1) represents the dispersion of muscle fibers in the plane (the plane formed by f0-n0), ρ out (Φ, b2) is used to describe the dispersion of muscle fibers outside the plane (the plane formed by s0-n0), b1 and b2 are concentration parameters used to indicate the degree of fiber divergence; G is a constant used to ensure that ρ(Θ, b1, Φ, b2) is integrated to 1 in the unit space, ρ in and ρ out Follows a π-periodic von Mises distribution.

[0067] Then, the direction of any divergent fiber is expressed, specifically, Figure 5 As shown, for any divergent fiber M n , and its direction is expressed as:

[0068] M n (Θ,Φ)=f0×cosΘ+n0×sinΘcosΦ+s0×sinΘsinΦ;

[0069] Among them, M n (Θ,Φ) represents any divergent fiber M n The direction of the probability density is ρ(Θ,b1,Φ,b2); Θ represents M n The angle between it and f0, Φ represents M n The angle between the projection on the plane s0-n0 and n0.

[0070] In step S3, a myocardial main dynamics model of the myocardial fiber structure is constructed according to the macroscopic distribution and microscopic distribution of the myocardial fiber structure in the constructed myocardium.

[0071] The traditional classical myocardial active force model does not consider the fiber divergence at the microscopic scale. When the fiber divergence at the microscopic scale is not considered, the model expression is:

[0072]

[0073] Among them, T a Is the active force value, F is the unit deformation gradient tensor. At this time, the main force is completely controlled by the macroscopic structure of the myocardial fiber.

[0074] The present invention breaks through the limitations of the existing technology and takes into account the microscopic divergent fibers more comprehensively. Based on the consideration of microscopic divergent fibers, the myocardial active force model is optimized as follows:

[0075]

[0076] Among them, T a Indicates the active force value, n f 、n s and n n Represents the active force value T a The distribution ratio of the three axes in the fiber axis coordinate system, σ a represents the optimized myocardial main force model, that is, the main force equation; represents the unit vector in the direction of the initial myocardial fiber deformation under the active force. Similarly, represents the unit vector after deformation in the initial transmural direction, represents the unit vector after deformation in the direction originally perpendicular to the fiber and transmural plane; and

[0077] Among them, the active force value T a The distribution ratio of the three axis directions in the fiber axis coordinate system can be calculated by the predefined fiber divergence probability density function, namely:

[0078]

[0079] Where S represents the unit integration space domain, and n f +n s +n n =1; H represents the myocardial fiber divergent structure tensor, M n represents any diverging fiber in the unit integral space domain. This model satisfies the active contraction behavior perpendicular to the average myocardial fiber direction observed in active contraction experiments.

[0080] Thus, the main dynamic model of myocardial fiber structure was constructed.

[0081] ①From the perspective of practical application:

[0082] On the one hand, this model can be used to simulate and predict heart disease, particularly in cardiac pathology research, providing more accurate analysis of myocardial mechanical behavior. Specifically, by simulating the distribution, contraction, and stress distribution of myocardial fibers, it can help doctors and researchers better understand changes in muscle function in heart diseases (such as heart failure and heart lesions) and provide a theoretical basis for treatment plans.

[0083] On the other hand, this model is also of great significance for personalized medicine. It can be combined with the patient's specific conditions (such as the distribution of myocardial fibers, the geometry of the heart, etc.) to perform customized treatment simulations to optimize surgical and treatment plans and reduce the patient's treatment risks.

[0084] ②From the perspective of real life:

[0085] The application of this model can significantly improve the diagnostic accuracy and treatment effectiveness of heart disease, especially for structural and functional changes in the heart that are difficult to observe using traditional methods, providing a more comprehensive and accurate assessment. This is of great significance for improving the survival rate and quality of life of heart disease patients. Through precise simulation and prediction, it can help reduce medical costs, minimize unnecessary treatments and surgical interventions, and provide new ideas for the development of the medical industry.

[0086] In order to further demonstrate the superiority of the method provided by the present invention, this embodiment also shows an application example of the myocardial active contractility model (i.e., the myocardial active dynamics model), specifically:

[0087] ① Basic parameters and environment settings are:

[0088] The left ventricular finite element model was loaded into the open source finite element calculation software FEniCS, and only the displacement of the reference plane of the mitral valve along the long axis was constrained, with no other constraints. a It is set as a linear function that increases with time and remains constant after reaching a peak of 120 kPa at 0.5 s.

[0089] ②The comparison process is:

[0090] A. Fiber divergence is not considered. That is, only two fiber rotation angles are compared here. For example, set β1 = -α1 = 40° and β2 = -α2 = 80°. At this time, n f =1,n n =n s = 0, then the main force equation is Compile the equation into FEniCS for calculation, and the result is as follows: Figure 6 As shown, it represents the stress distribution diagram of the heart wall in different angle ranges, specifically the component σ of the stress tensor along the direction of the myocardial fiber ff (Unit: kPa). Specifically, Figure 6 Figure 6 shows the stress distribution in the heart wall at different angles. The color bars indicate the magnitude of the stress, indicating the tensile and compressive stresses in different regions. As can be seen in Figure 6, the stress distribution varies significantly at different locations and in different directions in the heart wall, reflecting the influence of muscle fiber orientation on stress distribution.

[0091] Based on this, an important advantage of the present invention is that by adopting a rule-based fiber generation method, the distribution of myocardial fibers in different regions can be accurately described. The present invention dynamically assigns accurate fiber direction angles to each finite element by combining the angle change from the outside of the membrane to the inside of the membrane and the normalized thickness interpolation, reflecting the actual distribution of myocardial fibers. In the stress distribution diagram, the stress changes in different angle ranges indicate the influence of fiber direction on stress transfer, especially the difference in fiber direction significantly changes the contractile stress of the heart wall. This precise modeling method makes cardiac mechanics simulation more realistic and provides reliable theoretical support for heart disease research, treatment plan formulation and personalized medicine.

[0092] B. Consider fiber divergence. Select a fixed macroscopic fiber structure, for example: β=-α=60°. Select the b1 and b2 values in the probability density function ρ(Θ,b1,Φ,b2), and use the formula Calculate the corresponding n f 、n s 、n nHere, only two cases with different divergence degrees are compared. Furthermore, the parameter values set for the two cases with different divergence degrees are n f =1, n s =n n =0 and n f =0.6, n s =0, n n =0.4. The main driving force equation is Compile the equation into FEniCS for calculation, and the result is as follows: Figure 7 shown.

[0093] Figure 7 The figure shows the distribution of active stress in the heart wall under different fiber distribution parameters, and the color bar represents the magnitude of stress (unit: kPa). Figure 7 In the left figure, the fibers are oriented in the same direction, resulting in higher stresses in some areas and stronger active stresses. Figure 7 In the right figure, due to the certain dispersion of the fibers, the active stress distribution is more uniform and the stress in the local area is lower.

[0094] By considering fiber dispersion, the present invention provides a more accurate cardiac mechanics simulation method, thereby more realistically reflecting the mechanical behavior of the heart wall. This method can capture stress variations under different fiber distributions, reflecting the impact of cardiac wall heterogeneity on mechanical behavior. By simulating different fiber distributions, the present invention can optimize the cardiac mechanics model to make it more consistent with actual biomechanical properties, thereby providing a more reliable basis for clinical diagnosis and treatment.

[0095] Example 2

[0096] This embodiment discloses a system for constructing a dual-view myocardial fiber structure and a myocardial main force model.

[0097] The system for constructing a dual-view myocardial fiber structure and myocardial active force model includes:

[0098] The macroscopic distribution module is configured to: construct the macroscopic distribution of myocardial fiber structure in the myocardium based on a rule-based fiber generation method, specifically: set boundary conditions for the ventricular model and use Poisson's equation to perform interpolation calculations to determine the normalized thickness interpolation at the myocardial thickness; then, construct a fiber axis coordinate system within each finite element;

[0099] The microscopic distribution module is configured to: construct the microscopic distribution of myocardial fiber structure in the myocardium based on the probability density function, specifically: use the probability density function to characterize the dispersed fibers in the finite element unit, and construct the microscopic distribution of myocardial fibers in the myocardium according to the divergence degree of the dispersed fibers;

[0100] The myocardial main dynamics model construction module is configured to construct a myocardial main dynamics model of the myocardial fiber structure according to the macroscopic distribution and microscopic distribution of the myocardial fiber structure in the constructed myocardium.

[0101] Example 3

[0102] The purpose of this embodiment is to provide a computer-readable storage medium.

[0103] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the method for constructing a dual-view myocardial fiber structure and a myocardial active force model thereof as described in the first embodiment of the present disclosure.

[0104] Example 4

[0105] The purpose of this embodiment is to provide an electronic device.

[0106] An electronic device includes a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, the steps in the method for constructing a dual-view myocardial fiber structure and a myocardial active force model thereof as described in the first embodiment of the present disclosure are implemented.

[0107] The steps involved in the apparatuses of Examples 2, 3, and 4 above correspond to those of Method Example 1. For detailed implementations, please refer to the relevant description of Example 1. The term "computer-readable storage medium" should be understood to mean a single medium or multiple media containing one or more instruction sets; it should also be understood to include any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and causing the processor to perform any method of the present invention.

[0108] Those skilled in the art will appreciate that the modules or steps of the present invention described above can be implemented using a general-purpose computer device. Alternatively, they can be implemented using program code executable by a computing device, which can then be stored in a storage device and executed by the computing device. Alternatively, they can be fabricated into separate integrated circuit modules, or multiple modules or steps can be fabricated into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0109] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A method for constructing a dual-view myocardial fiber structure and myocardial main force model, characterized in that: include: A rule-based fiber generation method was used to construct the macroscopic distribution of myocardial fiber structure within the myocardium. Specifically, boundary conditions were set for the ventricular model, and Poisson's equation was used for interpolation calculation to determine the normalized thickness interpolation at the myocardial thickness. Subsequently, a fiber axis coordinate system was constructed within each finite element. The microscopic distribution of myocardial fiber structure in the myocardium is constructed based on the probability density function. Specifically, the probability density function is used to characterize the dispersed fibers in the finite element unit, and the microscopic distribution of myocardial fibers in the myocardium is constructed according to the divergence degree of the dispersed fibers. According to the macroscopic distribution and microscopic distribution of the myocardial fiber structure in the constructed myocardium, a myocardial main dynamics model of the myocardial fiber structure is constructed.

2. The method for constructing a dual-view myocardial fiber structure and myocardial main force model according to claim 1, characterized in that: Boundary conditions are set for the ventricular model; wherein the boundary conditions include initial values of all endocardial surface points and epicardial surface points in the ventricle.

3. The method for constructing a dual-view myocardial fiber structure and myocardial main force model according to claim 1, wherein: Poisson's equation is used for interpolation calculation to obtain the interpolation value and corresponding gradient direction of each point inside the myocardium; then, the obtained gradient direction is normalized to obtain a unit vector along the wall, and the obtained unit vector is perpendicular to the myocardial wall from inside to outside.

4. The method for constructing a dual-view myocardial fiber structure and myocardial main force model according to claim 1, wherein: A fiber axis coordinate system is constructed within each finite element unit, including: determining the longitudinal direction of the ventricle based on the geometric characteristics of the ventricle, determining the radial direction of the ventricle based on the longitudinal direction and the unit vector along the wall obtained by unitization, and multiplying the longitudinal direction by the radial direction to determine the circumferential direction of the ventricle; and constructing local direction coordinates according to the determined longitudinal direction, radial direction, and circumferential direction of the ventricle.

5. The method for constructing a dual-view myocardial fiber structure and myocardial main force model according to claim 4, characterized in that: The fiber angle value is assigned to each finite element in combination with the linear change of the angle from the outer membrane to the inner membrane to construct the fiber axis coordinate system.

6. The method for constructing a dual-view myocardial fiber structure and myocardial main force model according to claim 1, wherein: The probability density function is characterized by the dispersion function of the in-plane muscle fibers and the dispersion function of the out-of-plane muscle fibers.

7. The method for constructing a dual-view myocardial fiber structure and myocardial main force model according to claim 1, wherein: The main myocardial dynamics model is: Among them, T a Indicates the active force value, n f 、n s and n n They represent the distribution ratio of the active force value in the three axis directions of the fiber axis coordinate system, σ a represents the optimized myocardial active force model, The unit vector representing the direction of the initial myocardial fiber deformation under the action of the main force, represents the unit vector after deformation in the initial transmural direction, The unit vector representing the direction of the initial perpendicular fiber and transmural plane after deformation.

8. A system for constructing a dual-view myocardial fiber structure and myocardial main force model, characterized in that: include: The macroscopic distribution module is configured to: construct the macroscopic distribution of myocardial fiber structure in the myocardium based on a rule-based fiber generation method, specifically: set boundary conditions for the ventricular model and use Poisson's equation to perform interpolation calculations to determine the normalized thickness interpolation at the myocardial thickness; then, construct a fiber axis coordinate system within each finite element; The microscopic distribution module is configured to: construct the microscopic distribution of myocardial fiber structure in the myocardium based on the probability density function, specifically: use the probability density function to characterize the dispersed fibers in the finite element unit, and construct the microscopic distribution of myocardial fibers in the myocardium according to the divergence degree of the dispersed fibers; The myocardial main dynamics model construction module is configured to construct a myocardial main dynamics model of the myocardial fiber structure according to the macroscopic distribution and microscopic distribution of the myocardial fiber structure in the constructed myocardium.

9. A computer-readable storage medium having a program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method for constructing a dual-view myocardial fiber structure and a myocardial active force model thereof as described in any one of claims 1 to 7 are implemented.

10. An electronic device comprising a memory, a processor, and a program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps in the method for constructing a dual-view myocardial fiber structure and a myocardial active force model thereof as described in any one of claims 1 to 7 are implemented.

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