Target region determination method and apparatus

Abstract

The application relates to a target region determination method and device. The method comprises: acquiring a heart simulation model; the heart simulation model is composed of multiple volume elements; stress calculation is performed according to preset material parameters and the heart simulation model to determine theoretical stress parameters corresponding to each volume element; simulation calculation is performed according to the preset material parameters and the heart simulation model to determine simulation stress parameters corresponding to each volume element; the preset material parameters are adjusted according to a preset stress tolerance, the theoretical stress parameters and the simulation stress parameters to determine target material parameters; and the target region is accurately determined according to the target material parameters and the heart simulation model.

Description

Technical Field

[0001] This application relates to the field of medical simulation technology, and in particular to a method and apparatus for determining a target region. Background Technology

[0002] Hypertrophic cardiomyopathy (HCM) is a pathological heart disease caused by thickening of the myocardium. It usually leads to left ventricular outflow tract obstruction, severely affecting cardiac function and even causing life-threatening conditions. Treatment typically involves removing the thickened myocardial tissue to restore normal blood flow to the heart. In this procedure, the surgeon usually determines the area of ​​myocardial tissue to be removed based on their experience and imaging data.

[0003] In traditional techniques, imaging data can only provide macroscopic information such as anatomical morphology, ventricular volume, and ejection fraction. However, this macroscopic information cannot accurately reflect the internal state of the myocardial tissue of the object being analyzed. Therefore, staff members rely on their own experience and imaging data to determine the area of ​​myocardial tissue that needs to be removed. However, the above method cannot accurately determine the area of ​​myocardial tissue that needs to be removed.

[0004] Therefore, there is an urgent need for a method that can accurately determine the area of ​​myocardial tissue that needs to be removed. Summary of the Invention

[0005] Therefore, it is necessary to provide a method and apparatus for accurately determining the target area of ​​the myocardial tissue to be removed, in order to address the above-mentioned technical problems.

[0006] Firstly, this application provides a method for determining a target area. The method includes:

[0007] A heart simulation model is obtained; the heart simulation model is composed of multiple volumetric elements; stress calculation is performed based on preset material parameters and the heart simulation model to determine the theoretical stress parameters corresponding to each volumetric element; simulation calculation is performed based on the preset material parameters and the heart simulation model to determine the simulation stress parameters corresponding to each volumetric element; preset material parameters are adjusted based on preset stress tolerance, the theoretical stress parameters, and the simulation stress parameters to determine the target material parameters; a target region is determined based on the target material parameters and the heart simulation model.

[0008] In one embodiment, obtaining the cardiac simulation model includes: acquiring a 4D image of the target heart; establishing a simulation model of the target heart based on the 4D image, and determining the cardiac simulation model; the cardiac simulation model includes a free wall myocardial model and a ventricular septum model.

[0009] In one embodiment, the step of performing stress calculations based on preset material parameters and the heart simulation model to determine the theoretical stress parameters corresponding to each body unit includes: determining the displacement parameters of the target body unit based on the heart simulation model; the displacement parameters being the displacement vector of the target body unit from end-diastole to end-systole; the target body unit being any one of the plurality of body units; determining the theoretical strain parameters of the target body unit based on the displacement parameters of the target body unit; and determining the theoretical stress parameters of the target body unit based on the preset material parameters and the theoretical strain parameters.

[0010] In one embodiment, the body unit includes multiple nodes, and determining the displacement parameters of the target body unit according to the heart simulation model includes: determining the first coordinates of the multiple nodes of the target body unit at the end of diastole and the second coordinates of the multiple nodes of the target body unit at the end of systole according to the heart simulation model; determining the displacement parameters of each node in the target body unit according to the first coordinates and the second coordinates; and using the displacement parameters of each node in the target body unit as the displacement parameters of the target body unit.

[0011] In one embodiment, determining the theoretical strain parameters of the target body element based on its displacement parameters includes: obtaining the gradient vector corresponding to the target body element; determining the displacement gradient of the target body element based on the displacement parameters of each node in the target body element and the gradient vector corresponding to the target body element; determining the deformation gradient tensor of the target body element based on the displacement gradient of the target body element and a preset unit tensor; and determining the theoretical strain parameters of the target body element based on the deformation gradient tensor of the target body element and the preset unit tensor.

[0012] In one embodiment, determining the theoretical stress parameters of the target body element based on the preset material parameters and the theoretical strain parameters includes: differentiating a preset strain energy function to determine a stress solution function; and solving the theoretical strain parameters and the preset material parameters based on the stress solution function to determine the theoretical stress parameters of the target body element.

[0013] In one embodiment, the step of performing simulation calculations based on the preset material parameters and the heart simulation model to determine the simulation stress parameters corresponding to each body element includes: performing pressure load simulation calculations on the heart simulation model based on preset boundary conditions and preset material parameters to determine the simulation stress parameters corresponding to each body element.

[0014] In one embodiment, the step of adjusting the preset material parameters according to the preset stress tolerance, the theoretical stress parameters, and the simulated stress parameters to determine the target material parameters includes: calculating the stress norm corresponding to each volume element according to the theoretical stress parameters and the simulated stress parameters; if there is a target stress norm among all the stress norms that is greater than the preset stress tolerance, then adjusting the preset material parameters according to the preset material parameter adjustment rules and the actual pressure-volume curve to obtain the target material parameters.

[0015] In one embodiment, determining the target region based on the target material parameters and the heart simulation model includes: determining the target stress parameter, target strain parameter, target stress gradient parameter, and target strain gradient parameter for each volume element in the heart simulation model based on the target material parameters and the heart simulation model; constructing a first set of volume elements based on volume elements whose target stress parameters are greater than a preset stress threshold; constructing a second set of volume elements based on volume elements whose target strain parameters are greater than a preset strain threshold; constructing a third set of volume elements based on volume elements whose target stress gradient parameters are greater than a preset stress gradient threshold; constructing a fourth set of volume elements based on volume elements whose target strain gradient parameters are greater than a preset strain gradient threshold; and determining the intersection of the first set of volume elements, the second set of volume elements, the third set of volume elements, the fourth set of volume elements, and the interventricular septum model as the target region.

[0016] Secondly, this application also provides a target area determination device. The device includes:

[0017] An acquisition module is used to acquire a heart simulation model; the heart simulation model is composed of multiple volume units.

[0018] The theoretical determination module is used to perform stress calculations based on preset material parameters and the heart simulation model to determine the theoretical stress parameters corresponding to each volume element.

[0019] The simulation determination module is used to perform simulation calculations based on the preset material parameters and the heart simulation model to determine the simulation stress parameters corresponding to each volume element.

[0020] The adjustment module is used to adjust the preset material parameters according to the preset stress tolerance, the theoretical stress parameters, and the simulated stress parameters, and to determine the target material parameters;

[0021] The region determination module is used to determine the target region based on the target material parameters and the heart simulation model.

[0022] The aforementioned target region determination method and apparatus involve: acquiring a heart simulation model; the heart simulation model being composed of multiple volumetric units; performing stress calculations based on preset material parameters and the heart simulation model to determine the theoretical stress parameters corresponding to each volumetric unit; performing simulation calculations based on the preset material parameters and the heart simulation model to determine the simulation stress parameters corresponding to each volumetric unit; adjusting the preset material parameters based on the preset stress tolerance, the theoretical stress parameters, and the simulation stress parameters to determine the target material parameters; and accurately determining the target region based on the target material parameters and the heart simulation model. Attached Figure Description

[0023] Figure 1 This is an application environment diagram of the target region determination method in one embodiment;

[0024] Figure 2 This is a flowchart illustrating a target region determination method in one embodiment;

[0025] Figure 3 This is a flowchart illustrating the process of determining the theoretical stress parameters for each body element in one embodiment.

[0026] Figure 4 This is a structural block diagram of a target area determination device in one embodiment;

[0027] Figure 5 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0029] Hypertrophic cardiomyopathy (HCM) is a pathological heart disease caused by thickening of the myocardium. It is characterized by asymmetrical thickening of the interventricular septum, which often leads to left ventricular outflow tract obstruction, severely affecting cardiac function and even causing life-threatening conditions. Normal blood flow to the heart is generally restored by removing the thickened myocardial tissue. Therefore, accurately identifying the specific myocardial regions causing functional abnormalities is crucial for understanding the pathological mechanisms and guiding individualized management.

[0030] In related technologies, there is a problem of relying on a single evaluation indicator: For clinical imaging, such as echocardiography and cardiac MRI, while images can provide macroscopic indicators like anatomical morphology, ventricular volume, and ejection fraction, or strain parameters based on image deformation, they struggle to directly quantify the stress distribution within the intrinsic mechanical state of myocardial tissue, let alone accurately locate areas of abrupt mechanical abnormalities. Furthermore, there is a lack of individualized mechanical properties: emerging computational modeling methods can perform mechanical analysis by constructing finite element models of the heart. However, these methods are generally limited to using general or population-averaged material parameters, failing to reflect the true differences in the mechanical properties of the myocardial tissue of the specific subject under analysis, such as fibrosis or disordered arrangement caused by disease. In addition, key mechanical features are often overlooked: stress gradient is a crucial biomechanical indicator connecting local mechanical abnormalities to overall cardiac functional instability. Related technologies lack the ability to calculate and analyze stress gradient fields, thus making it difficult to accurately locate the "core abnormal zone" where the mechanical environment changes drastically.

[0031] Therefore, developing a technology that can integrate multimodal data of the subjects to be analyzed, realize the construction of individualized biomechanical models with high confidence, and accurately quantitatively identify abnormal biomechanical regions of the ventricular septum is of great clinical and scientific value.

[0032] The target region determination method provided in this application embodiment can be applied to, for example, Figure 1 In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store the data that server 104 needs to process. The data storage system can be integrated onto server 104 or located in the cloud or on other network servers. Server 104 is used to execute the target area determination method. Terminal 102 can be, but is not limited to, various personal computers, laptops, smartphones, tablets, IoT devices, and portable wearable devices. IoT devices can include smart speakers, smart TVs, smart air conditioners, smart vehicle devices, etc. Portable wearable devices can include smartwatches, smart bracelets, head-mounted devices, etc. Server 104 can be implemented using a standalone server or a server cluster consisting of multiple servers.

[0033] To address the aforementioned problems, in one embodiment of this application, such as Figure 2 As shown, a method for determining a target area is provided, including the following steps:

[0034] Step 201: Obtain the heart simulation model.

[0035] The cardiac simulation model is composed of multiple volume units. The cardiac simulation model is a simulation model of the left ventricle of the object to be analyzed, including a free-wall myocardial model and an interventricular septum model. The interventricular septum model is a simulation model of the septal muscle in the left ventricle of the object to be analyzed, and the free-wall myocardial model is a model of the myocardium in the left ventricle of the object to be analyzed excluding the septal muscle. A volume unit is the smallest constituent unit of the cardiac simulation model, and exemplary, it is tetrahedral.

[0036] It should be noted that the cardiac simulation model is a model obtained in advance by using existing simulation software to simulate and model the heart of the object to be analyzed in 4D images. This model is stored in a database beforehand, and when a cardiac simulation model is needed, the database is connected to retrieve it. The 4D images are time-varying images of the three-dimensional structure of the target heart, i.e., a sequence of cardiac images within a complete cardiac cycle of the object to be analyzed. The cardiac simulation model is a simulation model that changes over time.

[0037] Step 202: Perform stress calculations based on preset material parameters and the heart simulation model to determine the theoretical stress parameters corresponding to each body element.

[0038] The preset material parameters are the pre-defined material parameters of the heart of the object to be analyzed. The material parameters are used to characterize the properties of the myocardial tissue of the heart under stress.

[0039] In other embodiments of this application, the preset material parameters can be obtained by averaging the material parameters of multiple objects to be analyzed, or directly from literature or reports.

[0040] In this embodiment, the theoretical strain parameters of each body element are calculated based on the heart simulation model, and then the theoretical stress parameters corresponding to each body element are determined based on the theoretical strain parameters of each body element.

[0041] The theoretical stress parameter is a parameter characterizing the theoretical stress tensor of a volume element from the end of relaxation to the end of contraction, and the theoretical strain parameter is a parameter characterizing the theoretical strain tensor of a volume element from the end of relaxation to the end of contraction. The theoretical stress parameter and the theoretical strain parameter are in one-to-one correspondence with the volume element.

[0042] Step 203: Perform simulation calculations based on preset material parameters and the heart simulation model to determine the simulation stress parameters corresponding to each volume element.

[0043] In this embodiment, the heart simulation model is subjected to pressure load simulation calculation based on preset boundary conditions and preset material parameters, thereby obtaining the simulation stress parameters corresponding to each volume element.

[0044] The simulated stress parameters are the stress parameters of the volume elements obtained from the pressure load simulation calculation, and there is a one-to-one correspondence between the simulated stress parameters and the volume elements. The boundary conditions are the pre-set boundary conditions for the pressure load simulation, including ventricular constraint conditions and apical constraint conditions. Specifically, the ventricular constraint condition applies a fixed constraint on the atrioventricular ring plane of the base of the cardiac simulation model, i.e., the base of the left ventricle, to simulate the restricted movement of the left ventricle due to its connection with surrounding tissues such as the atrium, aorta, and pericardium. Specifically, the apical constraint condition applies no constraint to the apex of the heart, allowing it to move freely, to realistically reflect the torsion and longitudinal shortening of the apex during the cardiac cycle.

[0045] Step 204: Adjust the preset material parameters according to the preset stress tolerance, theoretical stress parameters and simulated stress parameters to determine the target material parameters.

[0046] In this embodiment, the stress norm corresponding to each volume element is calculated based on the theoretical stress parameters and the simulated stress parameters. If there is a target stress norm among all stress norms that is greater than the preset stress tolerance, the preset material parameters are adjusted according to the preset material parameter adjustment rules to obtain the target material parameters.

[0047] The stress norm is a parameter characterizing the difference between theoretical stress parameters and simulated stress parameters. The preset stress tolerance is a pre-defined threshold for the stress norm; if the stress norm exceeds the stress tolerance, it indicates that the preset material parameters are unreasonable and need adjustment. The preset material parameter adjustment rules are pre-determined rules for adjusting the material parameters. For example, the simulated pressure-volume curve corresponding to the preset material parameters can be determined based on the preset material parameters and the cardiac simulation model, and compared with the preset actual pressure-volume curve to adjust the preset material parameters. The pressure-volume curve is the curve corresponding to the pressure and volume of the left ventricle of the object under analysis within a preset pressure range.

[0048] The target material parameters are the adjusted material parameters of the heart of the object to be analyzed, which meet the preset adjustment rules.

[0049] Meeting the preset adjustment rules includes: the stress norm of each volume element corresponding to the adjusted material parameters is less than or equal to the preset stress tolerance, and the difference between the simulated pressure-volume curve corresponding to the adjusted material parameters and the actual pressure-volume curve is within the preset range.

[0050] Step 205: Determine the target area based on the target material parameters and the heart simulation model.

[0051] In this embodiment, based on the target material parameters and the cardiac simulation model, the target stress parameters, target strain parameters, target stress gradient parameters, and target strain gradient parameters of each volume element are determined and compared with preset thresholds for the target stress parameter, target strain parameter, target stress gradient parameter, and target strain gradient parameter, respectively. If any one of the target stress parameter, target strain parameter, target stress gradient parameter, and target strain gradient parameter of a volume element is greater than the corresponding threshold, the volume element is identified as a volume element with abnormal mechanical parameters. Then, the intersection of each volume element with abnormal mechanical parameters and the interventricular septum model is taken as the target region.

[0052] The target stress parameter is a parameter characterizing the stress tensor of the volume element. The target strain parameter is a parameter characterizing the strain tensor of the volume element. The target stress gradient parameter is a parameter characterizing the stress gradient of the volume element. The target strain gradient parameter is a parameter characterizing the strain gradient of the volume element. The target region is the area of ​​muscle to be removed in the ventricular septum model, i.e., the intersection of the set of volume elements with abnormal mechanical parameters and the ventricular septum model.

[0053] It should be noted that in this embodiment, whether the mechanical parameters of a volume element are abnormal is determined by comparing the mechanical parameters of the volume element with the corresponding mechanical threshold. If the mechanical parameters are greater than the corresponding mechanical threshold, it indicates that the mechanical parameters of the volume element are abnormal. The mechanical threshold corresponds one-to-one with the mechanical parameters of the volume element.

[0054] In the above method for determining the target region, a heart simulation model is obtained; the heart simulation model is composed of multiple volumetric elements; stress calculations are performed based on preset material parameters and the heart simulation model to determine the theoretical stress parameters corresponding to each volumetric element; simulation calculations are performed based on preset material parameters and the heart simulation model to determine the simulation stress parameters corresponding to each volumetric element; preset material parameters are adjusted based on preset stress tolerance, theoretical stress parameters, and simulation stress parameters to determine the target material parameters; and the target region is accurately determined based on the target material parameters and the heart simulation model.

[0055] In other embodiments of this application, obtaining a cardiac simulation model includes:

[0056] Step 1: Obtain a 4D image of the target heart.

[0057] The target heart is the heart of the subject to be analyzed, where the area of ​​myocardium to be removed needs to be determined. 4D imaging is a three-dimensional structural image of the target heart over time, specifically a sequence of cardiac images within a complete cardiac cycle of the subject. 4D images are obtained through cardiac imaging examinations such as cardiac magnetic resonance cine imaging, 3D ultrasound, or cardiac CT.

[0058] Step 2: Based on the 4D images, establish a simulation model of the target heart and determine the heart simulation model.

[0059] The cardiac simulation model includes a free wall myocardial model and a ventricular septum model. It is a 4D image of the heart of the object to be analyzed that needs to determine the area of ​​myocardial resection, and the model is obtained by simulation modeling using existing simulation software.

[0060] In other embodiments of this application, the process of constructing a cardiac simulation model is as follows: for 4D images, focusing on the end-diastolic and end-systolic phases, an automatic segmentation algorithm is used to extract the endocardial and epicardial surfaces of the left ventricle, and a three-dimensional geometric model of the left ventricular myocardium layer at end-diastolic ED is constructed based on the segmentation results, i.e., the cardiac simulation model. On this basis, according to anatomical landmarks, such as the virtual extension surface of the anterior and posterior interventricular grooves, the myocardial tissue is further divided into two independent parts: the free wall myocardial model and the interventricular septum model.

[0061] It should be noted that in this embodiment, after obtaining the 4D image of the target heart, a simulation model of the target heart will be established based on the 4D image to determine the heart simulation model, which lays the foundation for determining the target area based on the target material parameters and the heart simulation model.

[0062] In other embodiments of this application, such as Figure 3 As shown, stress calculations are performed based on preset material parameters and a heart simulation model to determine the theoretical stress parameters corresponding to each volume element, including:

[0063] Step 301: Determine the displacement parameters of the target body element based on the heart simulation model.

[0064] The displacement parameter is the displacement vector of the target volume element from the end of relaxation to the end of contraction.

[0065] It should be noted that the target body unit can be any one of multiple body units. In this embodiment, the steps are described using the target body unit as an example. In practice, the steps in this embodiment need to be performed on each body unit.

[0066] In this embodiment, based on the heart simulation model, the displacement parameters of the target volume element are specifically determined as follows:

[0067] Step 1: Based on the heart simulation model, determine the first coordinates of multiple nodes of the target body unit at the end of diastole and the second coordinates of multiple nodes of the target body unit at the end of systole.

[0068] It should be noted that the heart's pumping process includes systole and diastole.

[0069] In this embodiment, the heart simulation model at end-diastole and end-systole is extracted. Then, based on the model at end-diastole, the coordinates of each node of the target body unit at end-diastole are used as the first coordinates. Then, based on the model at end-systole, the coordinates of each node of the target body unit at end-systole are used as the second coordinates.

[0070] The first coordinate represents the coordinates of the node of the target volume element at the end of diastole, and the second coordinate represents the coordinates of the node of the target volume element at the end of systole. In this embodiment, the node of the volume element is the vertex of the volume element. For example, taking a tetrahedral volume element as an example, the nodes of the volume element in this embodiment are the four vertices of the tetrahedral volume element. The coordinates of the node represent the position of a certain volume element in the cardiac simulation model at a certain moment. It can be understood that the cardiac simulation model is a simulation model of the heart within one cardiac cycle, which will contract or relax over time, so the position of the volume element in the cardiac simulation model will also change over time.

[0071] Step 2: Determine the displacement parameters of each node in the target body element based on the first and second coordinates.

[0072] In this embodiment, for a certain node of the target body element, a vector is determined with the first coordinate of the node as the starting point and the second coordinate of the node as the ending point, and this vector is used as the displacement parameter of the node.

[0073] The displacement parameter is a parameter that characterizes the displacement of a node of the target body element from the end of diastole to the end of contraction. It is a vector with the first coordinate of the node as the starting point and the second coordinate of the node as the ending point.

[0074] It should be noted that in this embodiment, a cardiac simulation model with end-diastolic (ED) is used as the reference configuration for mechanical analysis, while a cardiac simulation model with end-systolic (ES) is selected as the current configuration. In other embodiments of this application, non-rigid registration is performed between the current configuration and the reference configuration to solve the spatial mapping relationship from the reference configuration to the current configuration, thereby obtaining the displacement parameters of each node in the target volume element.

[0075] For example, the displacement parameter of a node in the target element can be expressed as: ,in, Let be the displacement parameter of a node in the target element. The projection vector of the displacement parameter of a node in the target element onto the X-axis is obtained by subtracting the X-axis coordinate in the first coordinate system and the X-axis coordinate in the second coordinate system of the node. The projection vector of the displacement parameter of a node in the target element onto the Y-axis is obtained by subtracting the Y-axis coordinate in the first coordinate system and the Y-axis coordinate in the second coordinate system of the node. The projection vector of the displacement parameter of a node in the target element onto the Z-axis is obtained by subtracting the Z-axis coordinate in the first coordinate system and the Z-axis coordinate in the second coordinate system of the node. This indicates the spatial coordinates of a node in the target volume element at the end of diastole or systole.

[0076] Step 3: Use the displacement parameters of each node in the target element as the displacement parameters of the target element.

[0077] In this embodiment, the displacement parameters of each node in the target body element are directly used as the displacement parameters of the target body element.

[0078] The displacement parameters of the target body element are the displacement parameters of each node in the target body element, which characterize the overall displacement of the target body element from the end of diastole to the end of contraction.

[0079] Furthermore, after determining the displacement parameters of the target volume element, the displacement parameters of the target volume element are also smoothed and corrected for outliers to eliminate non-physiological deformation components caused by image noise or local registration errors. Then, the displacement parameters of the target volume element after smoothing and outlier correction are output.

[0080] Step 302: Determine the theoretical strain parameters of the target body element based on its displacement parameters.

[0081] In this embodiment, the gradient vector corresponding to the target volume element is obtained, and then the strain is calculated based on the displacement parameters of the target volume element, the gradient vector, and the preset unit tensor to obtain the theoretical strain parameters of the target volume element.

[0082] The gradient vector is a vector characterizing the gradient change of the target volume element from the end of relaxation to the end of contraction, and corresponds one-to-one with the volume element. The preset unit tensor is a pre-set unit vector. The theoretical strain parameter is a parameter characterizing the theoretical strain tensor of the target volume element.

[0083] Step 303: Determine the theoretical stress parameters of the target body element based on the preset material parameters and theoretical strain parameters.

[0084] In this embodiment, the theoretical stress parameters of the target body element are determined based on preset material parameters and theoretical strain parameters, including:

[0085] Step 1: Differentiate the preset strain energy function to determine the stress solution function.

[0086] In this embodiment, a hyperelastic, incompressible material model capable of characterizing the anisotropy of myocardial fibers is used to describe the passive material behavior of the myocardium. The strain energy function is a Holzapfel-Ogden type transverse anisotropic constitutive model, and its strain energy function is expressed as:

[0087] .

[0088] in, Let be the strain energy function. These are material parameters, theoretical values ​​in this embodiment, which can be optimized by fitting the simulated pressure-volume curve of the object being analyzed. It should be noted that it is assumed that the myocardium has different stiffness characteristics in the fiber direction and transverse direction to simulate its anisotropy. It is the first invariant of the right Cauchy-Green strain tensor. The right Cauchy-Green strain tensor of the target volume element is equal to the theoretical strain parameter of the target volume element multiplied by 2 and the preset unit tensor added. Let be the strain invariant along the fiber direction.

[0089] The stress solution function is the derivative of the strain energy function.

[0090] Step 2: Based on the stress solution function, solve for the theoretical strain parameters and preset material parameters to determine the theoretical stress parameters of the target body element.

[0091] In this embodiment, the theoretical strain parameters and preset material parameters are substituted into the stress solution function to obtain the theoretical stress parameters of the target body element.

[0092] The theoretical stress parameter is a parameter that characterizes the theoretical stress tensor of the target volume element from the end of relaxation to the end of contraction.

[0093] In this embodiment, the displacement parameters of the target body element are determined based on the heart simulation model, and the theoretical strain parameters of the target body element are determined based on the displacement parameters of the target body element. Finally, the theoretical stress parameters of the target body element are determined based on the preset material parameters and the theoretical strain parameters, laying the foundation for the subsequent determination of the target material parameters.

[0094] In other embodiments of this application, determining the theoretical strain parameters of the target body element based on its displacement parameters includes:

[0095] Step 1: Obtain the gradient vector corresponding to the target volume unit.

[0096] The gradient vector is a vector that characterizes the gradient change of the target volume unit from the end of diastole to the end of systole, and corresponds one-to-one with the volume unit.

[0097] It should be noted that the target body unit can be any one of multiple body units. In this embodiment, the steps are described using the target body unit as an example. In practice, the steps in this embodiment need to be performed on each body unit.

[0098] It should be noted that the gradient vector corresponding to the target volume element is obtained by taking the partial derivative of the shape function of the target volume element. The shape function is a set of interpolation functions defined on the volume element, whose function is to uniquely determine the displacement field at any position inside the element by weighted combination based on the known displacement values ​​at the nodes. One volume element corresponds to one shape function. For example, the shape function can be expressed as: ,in, Let V be the shape function, and V be the volume of the solid element. , , as well as The coefficients are preset and determined by the algebraic cofactors formed by the nodal coordinates. They are all constants that are only related to the element geometry of the volume element. Specifically, they are determined by solving a system of simultaneous equations based on the first coordinate, second coordinate, and displacement parameters of each node. X is the coordinate of a spatial point of the target volume element on the X-axis, Y is the coordinate of a spatial point of the target volume element on the Y-axis, and Z is the coordinate of a spatial point of the target volume element on the Z-axis.

[0099] It is understandable that, for a spatial point within the target volume element, its displacement from the end of diastole to the end of contraction can be expressed as a linear combination of the displacement parameters of each node within the target volume element: ,in, The displacement of a spatial point within the target volume element from the end of diastole to the end of systole. For shape functions, These are the displacement parameters of the nodes of the target element.

[0100] Based on the above interpolation expression for the displacement field, the gradient vector of the target volume element can be obtained by taking the partial derivatives of the shape function with respect to the spatial coordinates, specifically: Where V is the volume of the solid element. , as well as The preset coefficients, This is the gradient vector corresponding to the target volume element.

[0101] It should be noted that, in this embodiment, the gradient vector corresponding to the target volume unit is obtained from a database that pre-stores the gradient vectors corresponding to the target volume unit.

[0102] Step 2: Determine the displacement gradient of the target element based on the displacement parameters of each node in the target element and the gradient vector corresponding to the target element.

[0103] The displacement gradient is the displacement gradient tensor of the target volume element from the end of relaxation to the end of contraction, and it is represented as a matrix.

[0104] Since the shape function is a linear function of spatial coordinates, its partial derivatives are constant. Therefore, the displacement gradient within the volume element is constant. The specific calculation process is as follows: ,in, The displacement gradient of the target volume element. These are the displacement parameters of the nodes of the target element. This represents the diavector product, also known as the tensor product. This is the gradient vector corresponding to the target volume element.

[0105] Step 3: Determine the deformation gradient tensor of the target volume element based on the displacement gradient of the target volume element and the preset unit tensor.

[0106] The deformation gradient tensor of the target volume element is the deformation gradient tensor of the target volume element from the end of relaxation to the end of contraction, and its form is a matrix.

[0107] In this embodiment, the process of determining the deformation gradient tensor of the target volume element is as follows: ,in, Let be the deformation gradient tensor of the target volume element. The displacement gradient of the target volume element. This is a preset unit tensor.

[0108] Step 4: Determine the theoretical strain parameters of the target element based on the deformation gradient tensor and the preset unit tensor.

[0109] The theoretical strain parameter is a parameter that characterizes the theoretical strain tensor of the target volume element from the end of relaxation to the end of contraction, and it is expressed as a matrix.

[0110] It should be noted that, in this embodiment, the theoretical strain parameters of the target body element are determined based on "measured kinematic data + material constitutive relations".

[0111] In this embodiment, the theoretical strain parameters of the target volume element are determined as follows: ,in, These are theoretical strain parameters. Let be the deformation gradient tensor of the target volume element. Let be the transpose of the deformation gradient tensor of the target volume element. This is a preset unit tensor.

[0112] In other embodiments of this application, simulation calculations are performed based on preset material parameters and a heart simulation model to determine the simulation stress parameters corresponding to each volume element, including:

[0113] Based on the preset boundary conditions and preset material parameters, pressure load simulation calculations are performed on the heart simulation model to determine the simulation stress parameters corresponding to each volume element.

[0114] In this embodiment, pressure loads are applied to the heart simulation model according to preset boundary conditions and preset material parameters to perform simulation calculations, thereby obtaining the simulation stress parameters corresponding to each volume element.

[0115] It should be noted that, in this embodiment, the preset boundary conditions are pre-defined simulation boundary conditions, including ventricular constraint conditions and apical constraint conditions. For example, the ventricular constraint condition specifically applies a fixed constraint to the atrioventricular ring plane of the base of the cardiac simulation model, i.e., the base of the left ventricle, to simulate the restricted movement of the left ventricle due to its connection with surrounding tissues such as the atrium, aorta, and pericardium. The apical constraint condition specifically applies no constraint to the apex, allowing it to move freely, to realistically reflect the torsion and longitudinal shortening of the apex during the cardiac cycle. The pressure load is the intracavitary pressure of the left ventricle on the heart of the object under analysis during the period from end-diastole to end-systole, obtained through ultrasound or cardiac catheterization. The simulation stress parameter is a parameter characterizing the simulated stress tensor of the volume element during the period from end-diastole to end-systole. The simulated stress tensor is the stress tensor of the volume element obtained through simulation.

[0116] It should be noted that, in this embodiment, the cardiac simulation model is a finite element model obtained by importing the three-dimensional geometric model of the left ventricle at end-diastole into finite element analysis software, performing volume mesh generation, and then using it for mechanical calculations.

[0117] It should be noted that in this embodiment, the simulation calculation of the stress parameters corresponding to each volume element is achieved through finite element analysis. This involves solving the deformation process of the heart simulation model from end-diastole to end-systole under pressure load and preset material parameters. Subsequently, the model state of the heart simulation model at end-systole is extracted, and the simulation stress tensor of each volume element is output. The simulation stress tensor is obtained entirely from the heart simulation model through simulation calculations based on physical laws.

[0118] In this embodiment, by performing pressure load simulation calculations on the heart simulation model based on preset boundary conditions and preset material parameters, the simulation stress parameters corresponding to each volume element are determined, laying the foundation for subsequent determination of target material parameters.

[0119] In other embodiments of this application, the target material parameters are determined by adjusting the preset material parameters based on the preset stress tolerance, theoretical stress parameters, and simulated stress parameters, including:

[0120] Step 1: Calculate the stress norm for each volume element based on the theoretical stress parameters and the simulated stress parameters.

[0121] The stress norm is a parameter that characterizes the difference between theoretical stress parameters and simulated stress parameters.

[0122] In this embodiment, for each volume element, the norm of the difference between its theoretical stress parameters and simulated stress parameters is calculated and used as the stress norm corresponding to that volume element.

[0123] In this embodiment, the process of calculating the stress norm is as follows: ,in, To determine the stress norm of a solid element under preset material parameters. These are theoretical stress parameters. These are the simulation stress parameters.

[0124] Step 2: If among all stress norms there is a target stress norm that is greater than the preset stress tolerance, then adjust the preset material parameters according to the preset material parameter adjustment rules and the actual pressure-volume curve to obtain the target material parameters.

[0125] The actual pressure-volume curve is the curve showing the relationship between pressure and volume in the left ventricle of the object under analysis within a preset pressure range. It can be obtained by processing the actual data of the object under analysis using the Klotz single-beat estimation algorithm. This algorithm estimates the left ventricular end-diastolic pressure-volume relationship curve within a preset pressure range based on the end-systolic pressure, end-systolic volume, and end-diastolic volume within a cardiac cycle. The preset pressure range is a pre-determined pressure range, for example, 0–20 mmHg. The preset material parameter adjustment rules are pre-determined rules used to adjust the material parameters. The target material parameters are the final material parameters obtained.

[0126] It should be noted that in this embodiment, if there is a target stress norm greater than the preset stress tolerance among all stress norms, a simulation will be performed based on the heart simulation model to obtain the simulated pressure-volume curve corresponding to the heart simulation model, and the preset material parameters will be adjusted according to the preset material parameter adjustment rules. If there is a difference in volume between the simulated pressure-volume curve and the actual pressure-volume curve corresponding to a certain pressure value that is greater than or equal to 5% of the volume corresponding to that pressure value in the actual pressure-volume curve, the simulated pressure-volume curve will be updated, and the preset material parameters will be readjusted according to the preset material parameter adjustment rules until there is no difference in volume between the simulated pressure-volume curve and the actual pressure-volume curve corresponding to a certain pressure value that is greater than or equal to 5% of the volume corresponding to that pressure value in the actual pressure-volume curve. The stress norm corresponding to each body element is redefined. If there is still a target stress norm that is greater than the preset stress tolerance among all stress norms, the preset material parameters are readjusted. It is then determined whether there is a difference in volume corresponding to a certain pressure value between the simulated pressure-volume curve and the actual pressure-volume curve, which is greater than or equal to 5% of the volume corresponding to that pressure value in the actual pressure-volume curve. The finally adjusted material parameters are then used as the target material parameters.

[0127] It should be noted that the heart simulation model under the action of the target material parameters can be regarded as the model that can most accurately reflect the dynamic behavior of the myocardium of the object under analysis in a physiological state.

[0128] It should be noted that, in this embodiment, the preset material parameter adjustment rule is as follows: if the volume in the simulated pressure-volume curve is less than the volume in the actual pressure-volume curve, it indicates that the material of the heart corresponding to the preset material parameter is too hard, and the value of the preset material parameter needs to be reduced; if the volume in the simulated pressure-volume curve is greater than the volume in the actual pressure-volume curve, it indicates that the material of the heart corresponding to the preset material parameter is too soft, and the value of the preset material parameter needs to be increased.

[0129] It should be noted that the values ​​of the preset material parameters will affect the overall size of the simulated pressure-volume curve, but will not affect the overall trend of the simulated pressure-volume curve. Therefore, under the premise that the preset material parameters need to be adjusted, there are only two possible relationships between the simulated pressure-volume curve and the actual pressure-volume curve: the simulated pressure-volume curve is larger than the actual pressure-volume curve, or the simulated pressure-volume curve is smaller than the actual pressure-volume curve.

[0130] It should be noted that during the adjustment of preset material parameters, the isotropic parameters will be adjusted first. It primarily affects the overall stress level of the heart, and then adjusts the fiber orientation parameters. It mainly affects the local stress distribution in the heart.

[0131] The process of determining the simulated pressure-volume curve is as follows: apply increasing pressures ranging from 0 to 20 mmHg to the cardiac simulation model, obtain the volume of the left ventricle at each pressure value, and then plot the simulated pressure-volume curve.

[0132] It should be noted that if there is a difference between the volume corresponding to a certain pressure value in the simulated pressure-volume curve and the actual pressure-volume curve, which is greater than or equal to 5% of the volume corresponding to that pressure value in the actual pressure-volume curve, it indicates that the current material parameters deviate from reality and need to be readjusted.

[0133] In other embodiments of this application, determining the target region based on target material parameters and a heart simulation model includes:

[0134] Step 1: Based on the target material parameters and the heart simulation model, determine the target stress parameters, target strain parameters, target stress gradient parameters, and target strain gradient parameters for each volume element in the heart simulation model.

[0135] For each volumetric element, a simulation calculation is performed on the heart simulation model using the target material parameters. This yields the target stress and strain parameters for each node of each volumetric element. The target stress parameters for each node are then used as the target stress parameters for that volumetric element, and the target strain parameters for each node are used as the target strain parameters for that volumetric element. Based on the target stress parameters, the target stress gradient parameters for each volumetric element are determined. Finally, based on the target strain parameters, the target strain gradient parameters for that volumetric element are determined.

[0136] The target stress parameter is the stress tensor of a volume element during the period from the end of relaxation to the end of contraction, under the influence of the target material parameters. The target strain tensor is the strain tensor of a volume element during the period from the end of relaxation to the end of contraction, under the influence of the target material parameters. The target stress gradient parameter is the first partial derivative of the target stress parameter with respect to spatial coordinates, and the target strain gradient parameter is the first partial derivative of the target strain parameter with respect to spatial coordinates. The target stress gradient parameter characterizes the rate of change of the target stress parameter of the volume element in space; its high-amplitude region indicates abrupt changes in the mechanical state and is a key indicator for identifying local mechanical anomalies. The target strain gradient parameter characterizes the rate of change of the target strain parameter of the volume element in space; its high-amplitude region indicates abrupt changes in the mechanical state and is a key indicator for identifying local mechanical anomalies.

[0137] In this embodiment, the target stress parameters and target strain parameters of each volume element can be obtained by simulating the target material parameters using a heart simulation model.

[0138] It should be noted that the process of obtaining the target stress parameters and target strain parameters in this embodiment is the same as that of obtaining the simulation stress parameters corresponding to each body element. Based on the preset boundary conditions and target material parameters, a pressure load is applied to the heart simulation model for simulation calculation, thereby obtaining the stress tensor and strain tensor of the nodes of each body element. Then, the stress tensor of the nodes of each body element is used as the target stress parameter of the nodes of each body element, and the strain tensor of the nodes of each body element is used as the target strain parameter of the nodes of each body element.

[0139] In this embodiment, the target strain parameter of each volume element can be represented by shape function interpolation: ,in, The target strain parameter for the solid element. For shape functions, The target strain parameters for the nodes of the solid element.

[0140] It should be noted that in this embodiment, target strain parameters and other invariants, such as maximum principal strain, minimum principal strain, and maximum shear strain, are determined for each volume element to quantify the degree of local deformation of the myocardium.

[0141] It should be noted that the target strain parameters of each volume element are expressed in the form of Green-Lagrange strain tensor or Almansi strain tensor.

[0142] Furthermore, the formula for calculating the target strain gradient parameter of each volume element is as follows: ,in, The target strain gradient parameters for the bulk element. The target strain parameters for the nodes of the solid element. This represents the diaduplicate product or tensor product. This is the gradient vector corresponding to the target volume element.

[0143] In this embodiment, the target stress parameter of each volume element can be represented by shape function interpolation: ,in, The target stress parameters for the solid element. For shape functions, The target stress parameters for the nodes of the solid element.

[0144] It should be noted that in this embodiment, the target stress parameters and other invariants of each body element, such as the maximum principal stress, minimum principal stress, and von Mises equivalent stress, will be determined to assess the stress state of the myocardial tissue.

[0145] Furthermore, the formula for calculating the target stress gradient parameter of each volume element is as follows: ,in, The target stress gradient parameter for the solid element. The target stress parameters for the nodes of the solid element. This represents the diaduplicate product or tensor product. This is the gradient vector corresponding to the target volume element.

[0146] It should be noted that in this embodiment, the septal myocardial region is calculated and analyzed in detail using a cardiac simulation model under the action of the target material parameters in order to identify the abnormal mechanical region that causes left ventricular outflow tract obstruction.

[0147] Step 2: Construct the first set of body elements based on the body elements whose target stress parameters are greater than the preset stress threshold.

[0148] The preset stress threshold is a pre-defined threshold value for the target stress parameter. The first set of body elements is the set of body elements in the heart simulation model whose target stress parameter is greater than the preset stress threshold.

[0149] In this embodiment, the volume elements in the heart simulation model whose target stress parameters are greater than a preset stress threshold will be counted and these volume elements will be used as the first set of volume elements.

[0150] It should be noted that, in this embodiment, a preset stress threshold is set to identify areas on the interventricular septum model where the stress value is significantly higher than that of the surrounding normal myocardium. These are typically areas where excessive myocardial hypertrophy and fibrosis lead to increased local stiffness.

[0151] Step 3: Construct a second set of body elements based on body elements whose target strain parameters are greater than the preset strain threshold.

[0152] The preset strain threshold is a pre-defined threshold value for the target strain parameter. The second set of body elements is the set of body elements in the heart simulation model whose target strain parameter is greater than the preset strain threshold.

[0153] In this embodiment, the volume elements in the heart simulation model whose target strain parameters are greater than a preset strain threshold will be counted and these volume elements will be used as a second set of volume elements.

[0154] It should be noted that, in this embodiment, setting a preset strain threshold is to identify areas on the interventricular septum model with significantly abnormal strain, such as areas of excessive stretching or compression, which often correspond to areas of disordered myocardial fiber arrangement, asynchronous local contraction, or decreased deformation capacity caused by fibrosis.

[0155] Step 4: Construct a third set of body elements based on the body elements whose target stress gradient parameters are greater than the preset stress gradient threshold.

[0156] The preset stress gradient threshold is a pre-defined threshold for the target stress gradient parameter, and is a preset value. The third-body element set is the set of volume elements in the heart simulation model whose target stress gradient parameter is greater than the preset stress gradient threshold.

[0157] In this embodiment, the volume elements in the heart simulation model whose target stress gradient parameters are greater than a preset stress gradient threshold will be counted and these volume elements will be used as a third set of volume elements.

[0158] It should be noted that, in this embodiment, a preset stress gradient threshold is set to identify the region with the largest stress gradient amplitude in the interventricular septum model. Physiologically, regions with high stress gradients correspond to abrupt changes in mechanical load and are often the initiating regions for local tissue remodeling and fibrosis.

[0159] Step 5: Construct a fourth set of volume elements based on volume elements whose target strain gradient parameters are greater than the preset strain gradient threshold.

[0160] The preset strain gradient threshold is a pre-defined threshold for the target strain gradient parameter, and is a preset value. The fourth set of volume elements is the set of volume elements in the heart simulation model whose target strain gradient parameter is greater than the preset strain gradient threshold.

[0161] In this embodiment, the volume elements in the heart simulation model whose target strain gradient parameters are greater than a preset strain gradient threshold will be counted and these volume elements will be used as the fourth set of volume elements.

[0162] It should be noted that, in this embodiment, a preset strain gradient threshold is set to identify the region with the largest strain gradient amplitude on the interventricular septum model. Regions with high strain gradients indicate drastic spatial changes in local myocardial deformation. Studies have shown that in the heart after myocardial infarction, regions with extremely high strain gradients form at the boundary between the infarcted and non-infarcted areas.

[0163] Step 6: Determine the intersection of the first set of unit cells, the second set of unit cells, the third set of unit cells, the fourth set of unit cells, and the interventricular septum model as the target region.

[0164] The target region is the area of ​​muscle that needs to be removed in the ventricular septum model, that is, the intersection of the set of body units with abnormal mechanical parameters and the ventricular septum model.

[0165] In this embodiment, the intersection of the first body unit set, the second body unit set, the third body unit set, the fourth body unit set, and the ventricular septum model is determined based on the cardiac simulation model, and this intersection is used as the target region.

[0166] Furthermore, in this application, the first set of unit elements, the second set of unit elements, the third set of unit elements, and the fourth set of unit elements will be drawn on the cardiac simulation model in the form of a cloud map, and quantitative indicators such as the spatial location, geometric range, average stress level, and maximum gradient value of the intersection between the first set of unit elements, the second set of unit elements, the third set of unit elements, the fourth set of unit elements, and the ventricular septum model will be calculated.

[0167] It should be noted that, in this embodiment, the target stress parameters, target strain parameters, target stress gradient parameters, and target strain gradient parameters of each volume element in the heart simulation model are first determined based on the target material parameters and the heart simulation model. Then, a first set of volume elements is constructed based on volume elements whose target stress parameters are greater than a preset stress threshold. A second set of volume elements is constructed based on volume elements whose target strain parameters are greater than a preset strain threshold. A third set of volume elements is constructed based on volume elements whose target stress gradient parameters are greater than a preset stress gradient threshold. A fourth set of volume elements is constructed based on volume elements whose target strain gradient parameters are greater than a preset strain gradient threshold. Finally, the intersection of the first set of volume elements, the second set of volume elements, the third set of volume elements, the fourth set of volume elements, and the interventricular septum model is determined and used as the target region. This method determines the target region simply and efficiently, improving the overall reliability of the target region determination method provided in this application.

[0168] In other embodiments of this application, to evaluate the mechanical effects of removing the target region, this embodiment performs a parametric mechanical scenario simulation on a cardiac simulation model with the target region removed:

[0169] First, for the target area, multiple parameterized modification schemes for local tissue models are pre-specified, with parameters including the location, spatial range, and shape of the model modification. Then, in the cardiac simulation model, the ventricular septum model under different schemes is simulated by modifying the volume elements of the corresponding regions. For the ventricular septum models with different schemes, finite element analysis is performed under the action of target material parameters and preset boundary conditions to simulate the mechanical response of the heart under the same cyclic load, thereby obtaining the stress redistribution and strain redistribution of the ventricular wall in the modified cardiac simulation model. The focus is on observing the redistribution of stress, strain, stress gradient, and strain gradient in the modified area and its surrounding tissues, and assessing the potential impact of different schemes on the left ventricular mechanical environment. Then, for each scheme, it is scored according to a preset target evaluation system. The evaluation indicators of the target evaluation system include, but are not limited to: anomaly relief (the decrease in stress and strain gradients in the core abnormal mechanical area); mechanical compatibility (the relief of local strain concentration phenomena and the change in the uniformity of overall strain distribution); and structural safety (whether new stress or strain concentration areas are generated at the edge of the intervention area). Finally, the report outputs a ventricular septal myocardial biomechanics scenario analysis report for the object under analysis. The report integrates the following: the cardiac simulation model of the object under analysis and the range of model changes; the distribution cloud maps of the target stress parameters, target strain parameters, target stress gradient parameters, and target strain gradient parameters of the initial model and the model after changes under different schemes, as well as a quantitative comparison table of each evaluation index.

[0170] It should be noted that the target region determination method proposed in this application achieves cardiac material property inversion based on in vivo kinematic data of the object under analysis through a core closed loop of "from image to displacement, and from displacement to dual-stress path comparison and calibration". Based on this, a multi-dimensional mechanical assessment system encompassing stress, strain, and their spatial gradient field is innovatively constructed to accurately identify abnormal mechanical regions within the interventricular septum myocardium. Furthermore, this method establishes a parametric mechanical scene simulation framework, achieving a leap from "static image assessment" to "dynamic individualized mechanical function assessment" and then to "multi-scene mechanical response prediction". The target region determination method proposed in this application provides a novel quantitative analysis approach for understanding the mechanisms of cardiac disease and assessing the functional status of the interventricular septum myocardium.

[0171] It should be noted that the target region determination method provided in this embodiment is a method for identifying abnormal areas of interventricular septal myocardial function based on multimodal imaging and biomechanical analysis. Its core lies in: using the displacement parameters of the heart's motion displacement within the body and intraventricular pressure data as the basis, iteratively optimizing preset material parameters to ensure consistency between theoretical stress parameters and simulated stress parameters predicted based on pressure load simulation, thereby constructing a high-confidence biomechanical model specific to the target object—that is, a cardiac simulation model under the action of the target material parameters. Furthermore, using this model, the system calculates and analyzes the stress, strain, and spatial gradient field of the interventricular septal myocardium, thereby achieving precise localization, quantification, and mechanistic explanation of the target area causing interventricular septal myocardial dysfunction.

[0172] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0173] Based on the same inventive concept, this application also provides a target region determination apparatus for implementing the target region determination method described above. The solution provided by this apparatus is similar to the implementation scheme described in the above method; therefore, the specific limitations in one or more target region determination apparatus embodiments provided below can be found in the limitations of the target region determination method described above, and will not be repeated here.

[0174] In one embodiment of this application, such as Figure 4 As shown, a target area determination device is provided, comprising:

[0175] The acquisition module 100 is used to acquire a heart simulation model; the heart simulation model is composed of multiple volume units.

[0176] The theoretical determination module 200 is used to perform stress calculations based on preset material parameters and the heart simulation model to determine the theoretical stress parameters corresponding to each volume element.

[0177] The simulation determination module 300 is used to perform simulation calculations based on the preset material parameters and the heart simulation model to determine the simulation stress parameters corresponding to each volume element.

[0178] The adjustment module 400 is used to adjust the preset material parameters according to the preset stress tolerance, the theoretical stress parameters, and the simulated stress parameters, and to determine the target material parameters.

[0179] The region determination module 500 is used to determine the target region based on the target material parameters and the heart simulation model.

[0180] In other embodiments of this application, the acquisition module 100 is further configured to acquire a 4D image of the target heart; establish a simulation model of the target heart based on the 4D image, and determine the heart simulation model; the heart simulation model includes a free wall myocardial model and a ventricular septum model.

[0181] In other embodiments of this application, the theoretical determination module 200 is further configured to determine the displacement parameters of the target body unit based on the heart simulation model; the displacement parameters are the displacement vectors of the target body unit from end-diastole to end-systole; the target body unit is any one of the plurality of body units; the theoretical strain parameters of the target body unit are determined based on the displacement parameters of the target body unit; and the theoretical stress parameters of the target body unit are determined based on the preset material parameters and the theoretical strain parameters.

[0182] In other embodiments of this application, the theoretical determination module 200 is further configured to determine, based on the heart simulation model, the first coordinates of multiple nodes of the target body unit at the end of diastole and the second coordinates of multiple nodes of the target body unit at the end of systole; determine the displacement parameters of each node in the target body unit based on the first coordinates and the second coordinates; and use the displacement parameters of each node in the target body unit as the displacement parameters of the target body unit.

[0183] In other embodiments of this application, the theoretical determination module 200 is further configured to: obtain the gradient vector corresponding to the target volume element; determine the displacement gradient of the target volume element based on the displacement parameters of each node in the target volume element and the gradient vector corresponding to the target volume element; determine the deformation gradient tensor of the target volume element based on the displacement gradient of the target volume element and a preset unit tensor; and determine the theoretical strain parameters of the target volume element based on the deformation gradient tensor of the target volume element and the preset unit tensor.

[0184] In other embodiments of this application, the theoretical determination module 200 is further configured to differentiate the preset strain energy function to determine the stress solution function; and to solve the theoretical strain parameters and the preset material parameters according to the stress solution function to determine the theoretical stress parameters of the target body element.

[0185] In other embodiments of this application, the simulation determination module 300 is further configured to perform pressure load simulation calculations on the heart simulation model based on preset boundary conditions and preset material parameters, and determine the simulation stress parameters corresponding to each body element.

[0186] In other embodiments of this application, the adjustment module 400 is further configured to calculate the stress norm corresponding to each of the bulk elements based on the theoretical stress parameters and the simulated stress parameters; if among all the stress norms there exists a target stress norm that is greater than the preset stress tolerance, then the preset material parameters are adjusted according to the preset material parameter adjustment rules and the actual pressure-volume curve to obtain the target material parameters.

[0187] In other embodiments of this application, the region determination module 500 is further configured to determine, based on the target material parameters and the heart simulation model, the target stress parameters, target strain parameters, target stress gradient parameters, and target strain gradient parameters of each volume element in the heart simulation model; construct a first set of volume elements based on volume elements whose target stress parameters are greater than a preset stress threshold; construct a second set of volume elements based on volume elements whose target strain parameters are greater than a preset strain threshold; construct a third set of volume elements based on volume elements whose target stress gradient parameters are greater than a preset stress gradient threshold; construct a fourth set of volume elements based on volume elements whose target strain gradient parameters are greater than a preset strain gradient threshold; and determine the intersection of the first set of volume elements, the second set of volume elements, the third set of volume elements, the fourth set of volume elements, and the interventricular septum model as the target region.

[0188] Each module in the aforementioned target area determination device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the operations corresponding to each module.

[0189] In one embodiment of this application, a computer device is provided, which may be a server, and its internal structure diagram may be as follows. Figure 5As shown, the computer device includes a processor, memory, and a network interface connected via a system bus. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The database stores all relevant data for executing the target region determination method. The network interface communicates with external terminals via a network connection. When the computer program is executed by the processor, it implements a target region determination method.

[0190] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0191] In one embodiment of this application, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the target region determination method described in the above embodiment.

[0192] In one embodiment of this application, a computer-readable storage medium is provided, on which a computer program is stored, the computer program being executed by a processor to implement the steps of the target region determination method in the above-described method embodiments.

[0193] In one embodiment of this application, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps of the target region determination method in the above-described method embodiments.

[0194] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0195] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0196] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0197] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for determining a target region, characterized in that, The method includes: A heart simulation model is obtained; the heart simulation model is composed of multiple volume units. Stress calculations are performed based on preset material parameters and the heart simulation model to determine the theoretical stress parameters corresponding to each volume element. Simulation calculations are performed based on the preset material parameters and the heart simulation model to determine the simulation stress parameters corresponding to each volume element. The preset material parameters are adjusted based on the preset stress tolerance, the theoretical stress parameters, and the simulated stress parameters to determine the target material parameters; The target region is determined based on the target material parameters and the heart simulation model; The step of performing stress calculations based on preset material parameters and the heart simulation model to determine the theoretical stress parameters corresponding to each body unit includes: determining the displacement parameters of the target body unit based on the heart simulation model; the displacement parameters are the displacement vectors of the target body unit from end-diastole to end-systole; the target body unit is any one of the multiple body units; determining the theoretical strain parameters of the target body unit based on the displacement parameters of the target body unit; and determining the theoretical stress parameters of the target body unit based on the preset material parameters and the theoretical strain parameters. The body unit includes multiple nodes. Determining the displacement parameters of the target body unit according to the heart simulation model includes: determining the first coordinates of the multiple nodes of the target body unit at the end of diastole and the second coordinates of the multiple nodes of the target body unit at the end of systole according to the heart simulation model; determining the displacement parameters of each node in the target body unit according to the first coordinates and the second coordinates; and using the displacement parameters of each node in the target body unit as the displacement parameters of the target body unit.

2. The target area determination method according to claim 1, characterized in that, The acquisition of the cardiac simulation model includes: Acquire 4D images of the target heart; Based on the 4D images, a simulation model of the target heart is established, and the heart simulation model is determined; the heart simulation model includes a free wall myocardial model and a ventricular septum model.

3. The target region determination method according to claim 1, characterized in that, The step of determining the theoretical strain parameters of the target body element based on its displacement parameters includes: Obtain the gradient vector corresponding to the target volume unit; The displacement gradient of the target volume element is determined based on the displacement parameters of each node in the target volume element and the gradient vector corresponding to the target volume element. The deformation gradient tensor of the target body element is determined based on the displacement gradient of the target body element and the preset unit tensor. The theoretical strain parameters of the target body element are determined based on the deformation gradient tensor and the preset unit tensor of the target body element.

4. The target area determination method according to claim 1, characterized in that, The step of determining the theoretical stress parameters of the target body element based on the preset material parameters and the theoretical strain parameters includes: Differentiate the preset strain energy function to determine the stress solution function; Based on the stress solution function, the theoretical strain parameters and the preset material parameters are solved to determine the theoretical stress parameters of the target body element.

5. The target area determination method according to claim 1, characterized in that, The step of performing simulation calculations based on the preset material parameters and the heart simulation model to determine the simulation stress parameters corresponding to each volume element includes: Based on preset boundary conditions and preset material parameters, pressure load simulation calculations are performed on the heart simulation model to determine the simulation stress parameters corresponding to each body element.

6. The target region determination method according to claim 1, characterized in that, The step of adjusting the preset material parameters based on the preset stress tolerance, the theoretical stress parameters, and the simulated stress parameters to determine the target material parameters includes: Calculate the stress norm for each volume element based on the theoretical stress parameters and the simulated stress parameters. If among all the stress norms, there is a target stress norm that is greater than the preset stress tolerance, then the preset material parameters are adjusted according to the preset material parameter adjustment rules and the actual pressure-volume curve to obtain the target material parameters.

7. The target region determination method according to claim 1, characterized in that, The step of determining the target region based on the target material parameters and the heart simulation model includes: Based on the target material parameters and the heart simulation model, determine the target stress parameters, target strain parameters, target stress gradient parameters, and target strain gradient parameters for each volume element in the heart simulation model. A first set of volume elements is constructed based on volume elements whose target stress parameters are greater than a preset stress threshold. A second set of volume elements is constructed based on volume elements whose target strain parameters are greater than a preset strain threshold. A third set of volume elements is constructed based on volume elements whose target stress gradient parameters are greater than a preset stress gradient threshold; A fourth set of volume elements is constructed based on volume elements whose target strain gradient parameters are greater than a preset strain gradient threshold. The intersection of the first body unit set, the second body unit set, the third body unit set, the fourth body unit set, and the interventricular septum model is determined as the target region.

8. A target area determination device, characterized in that, The device includes: An acquisition module is used to acquire a heart simulation model; the heart simulation model is composed of multiple volume units. The theoretical determination module is used to perform stress calculations based on preset material parameters and the heart simulation model to determine the theoretical stress parameters corresponding to each volume element. The simulation determination module is used to perform simulation calculations based on the preset material parameters and the heart simulation model to determine the simulation stress parameters corresponding to each volume element. The adjustment module is used to adjust the preset material parameters according to the preset stress tolerance, the theoretical stress parameters, and the simulated stress parameters, and to determine the target material parameters; The region determination module is used to determine the target region based on the target material parameters and the heart simulation model; The theoretical determination module is used to determine the displacement parameters of the target body unit based on the heart simulation model; the displacement parameters are the displacement vectors of the target body unit from end-diastole to end-systole; the target body unit is any one of the multiple body units; the theoretical strain parameters of the target body unit are determined based on the displacement parameters of the target body unit; and the theoretical stress parameters of the target body unit are determined based on the preset material parameters and the theoretical strain parameters. The theoretical determination module is used to determine the first coordinates of multiple nodes of the target body unit at the end of diastole and the second coordinates of multiple nodes of the target body unit at the end of systole, based on the heart simulation model; determine the displacement parameters of each node in the target body unit based on the first and second coordinates; and use the displacement parameters of each node in the target body unit as the displacement parameters of the target body unit.

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