Biomagnetic signal-based four-dimensional cardiac function imaging method and device

Abstract

Provided in the present application are a biomagnetic signal-based four-dimensional cardiac function imaging method and device. The method comprises: acquiring a cardiac magnetic signal of a subject to be tested and dynamic structure information of a target torso part within a full cardiac cycle, wherein the target torso part at least comprises two lungs, a torso, and a heart chamber and a pericardium structure thereof, and the dynamic structure information comprises a contour structure and a plurality of frames of dynamic images; performing spatial registration on the dynamic structure information and a sensor acquiring the cardiac magnetic signal to obtain coordinates of the sensor in a coordinate system of the dynamic structure information; calculating and reconstructing a cardiac electrical excitation activity based on the dynamic structure information, the coordinates of the sensor, and the cardiac magnetic signal to obtain a calculation and reconstruction result; and converting the calculation and reconstruction result into a four-dimensional visualization image.

Description

A method and device for four-dimensional cardiac functional imaging based on biomagnetic signals

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese patent application No. 202411058622X, filed on August 2, 2024, entitled “Method and Apparatus for Four-Dimensional Cardiac Functional Imaging Based on Biomagnetic Signals”, which is incorporated herein by reference in its entirety. Technical Field

[0003] This application relates to the field of cardiac imaging technology, and in particular to a method and apparatus for four-dimensional cardiac functional imaging based on biomagnetic signals. Background Technology

[0004] In the modeling of non-invasive cardiac magnetic resonance imaging (NMR), traditional methods achieve non-invasive imaging and visualization of cardiac electrical excitation activity by measuring weak biological magnetic signals. This approach often treats the heart as a static object. While considering that aortic valve opening and ventricular ejection primarily occur after the QRS complex, treating the heart as stationary during the cardiac activation phase has some merit. However, this assumption of a static heart becomes inaccurate when analyzing cardiac repolarization processes. This is because cardiac systolic activity mainly occurs near the T wave, especially since the diagnostic criteria for myocardial ischemia or infarction are primarily manifested in the ST segment and T wave. Furthermore, the reconstruction process of unknown cardiac excitation activity using a limited number of sensor signals is flawed, and even minor changes in the geometry of the heart or trunk can lead to errors in the reconstruction results.

[0005] On the other hand, traditional non-invasive cardiac imaging techniques mainly focus on the reconstruction of the cardiac surface (including the epicardium and endocardium), lacking precise characterization and imaging of the depth information of the cardiac origin and the intramural activation delay. This, to some extent, limits its application efficacy in the diagnosis of complex cardiac diseases such as ventricular arrhythmias.

[0006] In summary, existing technologies suffer from insufficient integrity and accuracy in cardiac imaging. Summary of the Invention

[0007] This application provides a four-dimensional cardiac functional imaging method and device based on biomagnetic signals to overcome the deficiencies of insufficient completeness and accuracy in the prior art, and to achieve complete and accurate cardiac imaging.

[0008] This application provides a four-dimensional cardiac functional imaging method based on biomagnetic signals, comprising the following steps:

[0009] The magnetic signal of the subject under test and the dynamic structural information of the target trunk position during the whole cardiac cycle are acquired; wherein, the target trunk position includes at least the two lungs, trunk and its heart chambers and pericardial structure, and the dynamic structural information includes contour structure and multi-frame dynamic images;

[0010] Spatial registration is performed between the dynamic structural information and the sensor acquiring the magnetocardiogram signal to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information;

[0011] Based on the dynamic structural information, the coordinates of the sensor, and the magnetic field signal, the cardiac electrical excitation activity is reconstructed to obtain the reconstruction result;

[0012] The calculated reconstruction results are then converted into a four-dimensional visualization image.

[0013] According to the four-dimensional cardiac functional imaging method based on biomagnetic signals provided in this application, the step of calculating and reconstructing cardiac electrical excitation activity based on the dynamic structural information, the coordinates of the sensor, and the cardiac magnetic signals to obtain the calculated reconstruction result specifically includes:

[0014] A dynamic distributed cardiac equivalent source model is generated based on the multi-frame dynamic images throughout the entire cardiac cycle;

[0015] The dynamic lead field matrix is ​​calculated based on the dynamic distributed cardiac equivalent source model, the coordinates of the sensor, and the contour structure.

[0016] Based on the said magnetic signal and the said dynamic lead field matrix, the cardiac electrical excitation activity is reconstructed, and the reconstruction result is obtained.

[0017] According to the four-dimensional cardiac functional imaging method based on biomagnetic signals provided in this application, the step of spatially registering the dynamic structural information and the sensor acquiring the cardiac magnetic signals to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information specifically includes:

[0018] Each surface imaging marker is marked with its first spatial coordinate in the coordinate system of the dynamic structural information, and each magnetocardiogram measurement marker is recorded with its second spatial coordinate in the digital coordinate system using a digital measuring device; wherein, the surface imaging marker is a preset number of markers set on the torso of the subject during the acquisition of the dynamic structural information, and the magnetocardiogram measurement marker is the preset number of markers set on the torso of the subject during the measurement of the magnetocardiogram signal, and the positions of the preset number of surface imaging markers and the preset number of magnetocardiogram measurement markers correspond one-to-one, and the preset number is at least 4;

[0019] Align the first spatial coordinates and the second spatial coordinates according to the consistent position of the surface angiography markers and the magnetocardiography markers to obtain the transformation matrix between the coordinate system of the dynamic structural information and the digital coordinate system;

[0020] The sensor position is obtained by calculating the relative position of the magnetocardiogram signal sensor with respect to the magnetocardiogram measurement marker;

[0021] The coordinates of the sensor in the coordinate system of the dynamic structure information are obtained based on the sensor position and the transformation matrix.

[0022] According to the four-dimensional cardiac functional imaging method based on biomagnetic signals provided in this application, the step of generating a dynamic distributed cardiac equivalent source model throughout the entire cardiac cycle based on the multi-frame dynamic images specifically includes:

[0023] Determine the template frame from the multi-frame dynamic images;

[0024] Based on the similarity between the template frame and other multi-frame dynamic images, the diastolic and systolic images in the whole cardiac cycle are registered to obtain the deformation field;

[0025] Grid points are placed in the three-dimensional space corresponding to the target space range of the template frame to serve as the heart equivalent source distributed model of the template frame; wherein, the target space range is the region inside the pericardium and outside the heart chamber in the image;

[0026] The cardiac equivalent source distributed model of the template frame is adjusted according to the deformation field to obtain the cardiac equivalent source distributed model corresponding to each frame of dynamic image, and then the dynamic distributed cardiac equivalent source model within the whole cardiac cycle is obtained.

[0027] According to the four-dimensional cardiac functional imaging method based on biomagnetic signals provided in this application, the step of calculating and reconstructing cardiac electrical excitation activity based on the cardiac magnetic signal and the dynamic lead field matrix to obtain the calculation and reconstruction result specifically includes:

[0028] Based on the minimum residual principle, a cost function is constructed based on the residual term and the regularization term corresponding to the regularization constraint; wherein, the residual term is the difference between the magnetic field signal and the simulated data obtained by forward calculation through the dynamic lead field matrix;

[0029] Minimize the cost function to obtain the activity changes of each source in the source model after reconstruction as the calculation reconstruction result.

[0030] According to the present application, a four-dimensional cardiac function imaging method based on biomagnetic signals is provided, wherein the four-dimensional visualization image includes at least one of a cardiac current density distribution change map, a cardiac activation and recovery map, and a cardiac activity main frequency distribution map.

[0031] This application also provides a four-dimensional cardiac function imaging device based on biomagnetic signals, comprising the following modules:

[0032] The structural information acquisition module is used to acquire the dynamic structural information of the target trunk of the test object during the entire cardiac cycle; wherein, the target trunk includes at least the two lungs, trunk and its heart chambers and pericardial structures, and the dynamic structural information includes contour structure and multi-frame dynamic images;

[0033] A magnetic signal acquisition module is used to acquire the magnetic signal of the subject under test;

[0034] A three-dimensional spatial registration module is used to perform spatial registration between the dynamic structural information and the sensor that acquires the magnetocardiogram signal, so as to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information;

[0035] The data processing module is used to calculate and reconstruct cardiac electrical excitation activity based on the dynamic structural information, the coordinates of the sensor, and the magnetic signal, and obtain the calculation and reconstruction results;

[0036] The four-dimensional visualization module is used to convert the calculation and reconstruction results into four-dimensional visualization images.

[0037] This application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the four-dimensional cardiac functional imaging method based on biomagnetic signals as described above.

[0038] This application also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the four-dimensional cardiac functional imaging method based on biomagnetic signals as described above.

[0039] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the four-dimensional cardiac functional imaging method based on biomagnetic signals as described above.

[0040] This application provides a four-dimensional cardiac functional imaging method and apparatus based on biomagnetic signals. It acquires the magnetic resonance imaging (MRI) signals of the subject and the dynamic structural information of the target trunk within the entire cardiac cycle. The target trunk includes at least the lungs, trunk, heart chambers, and pericardial structures. The dynamic structural information includes contour structures and multiple dynamic images. Spatial registration is performed between the dynamic structural information and the sensor acquiring the MRI signals to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information. Based on the dynamic structural information, the sensor coordinates, and the MRI signals, cardiac electrical excitation activity is calculated and reconstructed to obtain the calculation and reconstruction result. The calculation and reconstruction result is then converted into a four-dimensional visualized image. This application combines cardiac magnetic imaging and cardiac motion. Based on the acquired dynamic structural information and MRI signals, it fully utilizes the characteristics of biomagnetic signals and integrates signal processing technology through spatial registration to achieve accurate reconstruction and visualization of the four-dimensional representation of the heart and its functional activities. This results in a four-dimensional visualized image that comprehensively represents the dynamic electrophysiological activities of the entire heart (including the epicardium, endocardium, and intramural tissues) throughout the cardiac cycle, providing a novel technical solution for non-invasive imaging of cardiac electrical excitation activity. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 is a flowchart illustrating the four-dimensional cardiac functional imaging method based on biomagnetic signals provided in this application;

[0043] Figure 2 is a schematic diagram of the process of constructing a dynamic distributed cardiac equivalent source model throughout the entire cardiac cycle using the four-dimensional cardiac functional imaging method based on biomagnetic signals provided in this application.

[0044] Figure 3 is a schematic diagram of the dynamic lead field matrix of the four-dimensional cardiac functional imaging method based on biomagnetic signals provided in this application.

[0045] Figure 4 is a schematic diagram of the computational reconstruction results of the four-dimensional cardiac functional imaging method based on biomagnetic signals provided in this application;

[0046] Figure 5 is one of the schematic diagrams of four-dimensional visualization images of the four-dimensional cardiac function imaging method based on biomagnetic signals provided in this application;

[0047] Figure 6 is the second of the four-dimensional visualization images of the four-dimensional cardiac function imaging method based on biomagnetic signals provided in this application;

[0048] Figure 7 is the third of the four-dimensional visualization images of the four-dimensional cardiac function imaging method based on biomagnetic signals provided in this application;

[0049] Figure 8 is a schematic diagram of the structure of the four-dimensional cardiac functional imaging device based on biomagnetic signals provided in this application; and

[0050] Figure 9 is a schematic diagram of the structure of the electronic device provided in this application. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] Understandably, cardiac magnetic imaging is a technique that uses the measurement of weak biological magnetic signals to achieve non-invasive imaging and visualization of cardiac electrical excitation activity, which has important guiding significance for the diagnosis and treatment of heart diseases such as coronary heart disease, arrhythmia, and myocardial ischemia.

[0053] The electrical activity of the heart determines its physiological function of pumping blood. A complete cardiac cycle begins at the heart's pacemaker—the sinoatrial node (SA node). Electrical signals from the SA node trigger electrical excitation in the atrial myocytes, leading to atrial contraction. During this process, blood is effectively pumped from the atria into the ventricles. Subsequently, the electrical signal travels from the SA node to the atrioventricular node (AV node) located between the atria and ventricles, and then, via Purkinje fibers, rapidly and systematically spreads to both ventricles. Upon receiving the electrical signal, the ventricular myocytes become excited, triggering a powerful ventricular contraction that propels blood from the heart into the systemic circulatory system. Finally, the ventricular myocytes undergo repolarization, returning to a resting state and preparing for the next cardiac cycle.

[0054] Electromagnetic theory indicates that electric current signals are always accompanied by magnetic field signals. Unlike electrocardiogram (ECG) signals, magnetic signals are almost unaffected by the non-uniform conductivity of body tissues, making them more reliable in detecting biological phenomena. Furthermore, due to the different physical properties of electric and magnetic fields, cardiac magnetic field signals are sensitive to tangential and eddy current sources, while electric signals are more sensitive to radial sources. The cardiac magnetic field signal may provide information that is difficult to obtain from ECGs or surface potential maps. Therefore, non-invasive cardiac magnetic imaging can provide spatiotemporal information on cardiac electrical excitation, solving the problem of locating small lesions in typical cardiovascular diseases such as coronary heart disease and arrhythmias. It can be used for large-scale screening of heart disease, auxiliary diagnosis, and preoperative guidance for cardiac ablation surgery. Based on this, this application provides a method and device for four-dimensional cardiac functional imaging based on biomagnetic signals.

[0055] The following describes the four-dimensional cardiac functional imaging method based on biomagnetic signals of this application with reference to Figures 1-7. Figure 1 is a schematic flowchart of the four-dimensional cardiac functional imaging method based on biomagnetic signals provided by this application. As shown in Figure 1, the method includes the following steps.

[0056] Step 110: Obtain the magnetic signal of the subject under test and the dynamic structural information of the target trunk position during the whole cardiac cycle; wherein, the target trunk position includes at least the lungs, trunk and its heart chambers and pericardial structure, and the dynamic structural information includes contour structure and multi-frame dynamic images.

[0057] It should be noted that the acquired data includes multi-channel cardiac magnetic signals of the subject, as well as the contour structure and multi-frame dynamic images of the target torso position throughout the entire cardiac cycle. The multi-channel cardiac magnetic signals are also known as cardiac magnetic signals, and the contour structure and multi-frame dynamic images are collectively referred to as dynamic structural information. The target torso position includes at least the subject's lungs, trunk, heart chambers, and pericardial structures.

[0058] This application does not limit the devices and methods for acquiring dynamic structural information. In some embodiments, dynamic structural information is acquired using any one of magnetic resonance imaging (MRI), computed tomography (CT), echocardiography (EC), or a combination thereof.

[0059] Furthermore, in some embodiments, obtaining dynamic structural information includes the following steps: acquiring multiple frames of dynamic images of the target torso position of the subject during the entire cardiac cycle, performing three-dimensional reconstruction on the images, segmenting and extracting the contour structure of the target torso position based on the results of the three-dimensional reconstruction, and finally obtaining the dynamic structural information of the heart.

[0060] The magnetocardiogram (MCC) signal referred to in this application is extracted using a distributed magnetic sensor array. This application does not limit the specific equipment and methods for acquiring the MCC signal. In some embodiments, the MCC signal is acquired using any one of the following methods: a magnetocardiometer based on a superconducting quantum interference device (SQUID), an optically pumped magnetometer (OPM) array, or an atomic magnetometry (AM) array. In one specific embodiment, the device for acquiring the MCC signal is a 168-channel optically pumped magnetometer array consisting of 84 biaxially oriented sensors arranged on all four sides, with 30 sensors on the front of the chest, 30 on the back, and 12 on each side.

[0061] Furthermore, the test subject referred to in this application can be any living organism, including but not limited to mammals such as dogs and pigs, as well as non-human primates such as monkeys, and this application does not impose any restrictions on this.

[0062] Step 120: Spatial registration is performed on the dynamic structural information and the sensor that acquires the magnetocardiogram signal to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information.

[0063] The purpose of step 120 is to ensure that the spatial coordinates of the sensor extracting the magnetocardiogram signal are precisely aligned with the structural image of the dynamic structural information in the same spatial coordinate system. In the specific registration process, the torso of the subject is marked during the acquisition of dynamic structural information and the acquisition of the magnetocardiogram signal. Spatial registration is performed based on the set marks, and then the coordinates of the sensor in the coordinate system of the dynamic structural information are obtained based on the registration result. This application will further explain the specific steps of spatial registration and obtaining the sensor's coordinates in the coordinate system of the dynamic structural information in subsequent embodiments.

[0064] Step 130: Calculate and reconstruct cardiac electrical excitation activity based on the dynamic structural information, the coordinates of the sensor, and the magnetic signal to obtain the calculation and reconstruction result.

[0065] In step 130, the cardiac magnetic signal throughout the entire cardiac cycle is dynamically reconstructed by combining the cardiac electrical excitation activity reconstruction results (i.e., cardiac magnetic signal), the dynamic structural data of the test object (i.e., dynamic structural information), and the coordinates of the sensor.

[0066] Step 140: Convert the calculated reconstruction results into a four-dimensional visualization image.

[0067] In step 140, the cardiac function activity data in the reconstructed computational results are converted into a four-dimensional image and visualized. Simultaneously, the visualized four-dimensional image can be stored on a computing terminal and display device. It is important to emphasize that the generated four-dimensional visualized image comprehensively covers the functional activity of the entire heart (including the epicardium, endocardium, and intramural tissues) throughout a complete cardiac cycle.

[0068] This application fully utilizes the characteristics of biomagnetic signals and integrates signal processing technology through spatial registration to achieve precise reconstruction of the four-dimensional representation of the heart and visualization of its functional activities. It can not only capture static images of the heart structure but also dynamically display the functional changes of the heart during the cardiac cycle. This is of great significance for a deeper understanding of the electrophysiological characteristics of the heart and further observation of related cardiac regions.

[0069] The following provides a further explanation of step 120. In some embodiments, spatial registration of the dynamic structural information and the sensor acquiring the magnetocardiogram signal to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information specifically includes:

[0070] Step 121: Mark the first spatial coordinates of each surface imaging marker in the coordinate system of the dynamic structural information, and record the second spatial coordinates of each magnetocardiogram measurement marker in the digital coordinate system using a digital measuring device; wherein, the surface imaging marker is a preset number of markers set on the torso of the subject during the acquisition of the dynamic structural information, and the magnetocardiogram measurement marker is the preset number of markers set on the torso of the subject during the measurement of the magnetocardiogram signal, the positions of the preset number of surface imaging markers and the preset number of magnetocardiogram measurement markers correspond one-to-one, and the preset number is at least 4;

[0071] Step 122: Align the first spatial coordinates and the second spatial coordinates according to the consistent positions of the surface imaging markers and the magnetocardiogram measurement markers to obtain the transformation matrix between the coordinate system of the dynamic structural information and the digital coordinate system;

[0072] Step 123: Calculate the relative position of the magnetocardiogram sensor with respect to the magnetocardiogram measurement marker to obtain the sensor position;

[0073] Step 124: Obtain the coordinates of the sensor in the coordinate system of the dynamic structure information based on the sensor position and the transformation matrix.

[0074] Specifically, it should be noted that, to facilitate spatial registration, during the acquisition of magnetocardiographic signals and dynamic structural information in step 110, markers are set on the torso of the subject. Specifically, during the acquisition of dynamic structural information, a predetermined number of markers are set on the torso of the subject, and these are designated as surface imaging markers; during the acquisition of magnetocardiographic signals, a predetermined number of markers are set on the torso of the subject, and these are designated as magnetocardiographic measurement markers.

[0075] It should be noted that the number of surface angiography markers and the number of magnetocardiogram (MCG) measurement markers are the same, and their positions correspond one-to-one. In other words, a preset number of surface angiography markers correspond one-to-one with a preset number of MCG measurement markers, and the corresponding surface angiography markers and MCG measurement markers are located in the same position.

[0076] In some embodiments, the surface imaging markers are made of grease, and the magnetocardiogram markers are marker coils.

[0077] Furthermore, it should be emphasized that the preset quantity is at least 4. In one specific embodiment, the preset quantity is 4.

[0078] In step 121, the first spatial coordinates of each surface contrast marker in the coordinate system of dynamic structural information are marked. It is understood that the coordinate system of dynamic structural information is typically the coordinate system of the device acquiring the dynamic structural information. For example, in a specific embodiment, if an MRI device is used to acquire dynamic structural information, then the coordinate system of the dynamic structural information is the MRI coordinate system. In this case, the first spatial coordinates of the surface contrast marker can be marked manually.

[0079] While marking the first spatial coordinates of the surface angiography markers, a digital measuring device is used to record the second spatial coordinates of each magnetocardiogram (MCC) measurement marker in a digital coordinate system. It is important to emphasize that the digital coordinate system refers to the coordinate system of the digital measuring device used. For example, based on the above embodiment, if a marker coil is used as the MCC measurement marker, then an electromagnetic digitizer is used to record the second spatial coordinates of the marker coil in the digitized coordinate system of the electromagnetic digitizer.

[0080] In step 122, a predetermined number of individual surface angiography markers in the coordinate system of the dynamic structural information are aligned with a predetermined number of magnetocardiogram (MCG) measurement markers in the digitized coordinate system to obtain a transformation matrix between the two spatial coordinate systems. Specifically, the first and second spatial coordinates are aligned using surface angiography markers and MCG measurement markers with consistent positions to minimize the matching error, thus obtaining the transformation matrix between the coordinate system of the dynamic structural information and the digitized coordinate system. In some embodiments, a non-iterative least squares method is used to align the predetermined number of individual surface angiography markers in the coordinate system of the dynamic structural information with the predetermined number of MCG measurement markers in the digitized coordinate system.

[0081] In step 123, the position of the sensor acquiring the magnetocardiogram signal relative to the magnetocardiogram measurement marker is calculated to obtain the sensor position. In this step, since the relative positional relationship of the sensors in the distributed magnetic sensor array acquiring the magnetocardiogram signal is determined, the sensor positions of all sensors can be generalized by measuring the relative position of the magnetocardiogram measurement marker and a certain sensor. Based on the above embodiment, a marker coil is used as the magnetocardiogram measurement marker. Simultaneously, when the OPM device acquires the magnetocardiogram signal, a stable frequency sine wave signal is applied through a high-precision current source. Based on this, the magnetic field generated by the marker coil is used to calculate the sensor position of the OPM sensor relative to the marker coil.

[0082] In step 124, the coordinates of the sensor in the coordinate system of the dynamic structure information are obtained according to the sensor position and the transformation matrix, and spatial registration is completed.

[0083] This application embodiment utilizes spatial registration technology to place the sensor acquiring the cardiac magnetic signal and the dynamic structural information in the same coordinate system, enabling this non-invasive cardiac magnetic imaging to provide more accurate spatiotemporal information on cardiac electrical excitation activity, facilitating subsequent signal integration.

[0084] The following provides a further explanation of step 130. In some embodiments, the step of calculating and reconstructing cardiac electrical excitation activity based on the dynamic structural information, the coordinates of the sensor, and the magnetic field signal to obtain the calculated reconstruction result specifically includes:

[0085] Step 131: Generate a dynamic distributed cardiac equivalent source model throughout the entire cardiac cycle based on the multi-frame dynamic images;

[0086] Step 132: Calculate the dynamic lead field matrix based on the dynamic distributed cardiac equivalent source model, the coordinates of the sensor, and the contour structure;

[0087] Step 133: Calculate and reconstruct cardiac electrical excitation activity based on the magnetic field signal and the dynamic lead field matrix to obtain the calculation and reconstruction results.

[0088] Specifically, in step 131, as shown in Figure 2, a distributed cardiac equivalent source model for each frame of the image is constructed using multiple frames of dynamic images, resulting in a dynamic distributed cardiac equivalent source model throughout the entire cardiac cycle. Then, in step 132, based on the obtained dynamic distributed cardiac equivalent source model, the dynamic lead field matrix is ​​calculated using the sensor coordinates obtained in step 120 and the contour structure acquired in step 110 (as shown in Figure 3). In some embodiments, the aforementioned dynamic lead field matrix is ​​calculated using the boundary element method or the finite element method.

[0089] In one specific embodiment, the boundary element method is used to calculate the aforementioned dynamic lead field matrix. The boundary surface is discretized into a finite number of triangular surface elements, and the theoretical mathematical physics calculation equations for calculating the magnetic field from source activity, obtained from Maxwell's equations, are transformed into a system of linear algebraic equations, thereby obtaining the lead field matrix.

[0090] In the calculation, the conductivity of the heart was taken as 0.0537-0.483 S / m, the conductivity of the lungs as 0.5 S / m, the conductivity of the trunk as 0.216-0.241 S / m, and the conductivity of the heart chambers as 0.4-1.0 S / m.

[0091] In step 133, the cardiac electrical excitation activity is reconstructed using the magnetocardiogram signal and the dynamic lead field matrix to obtain the final reconstruction result. It should be noted that the reconstruction result includes the activity changes after reconstruction for each source in the source model. In some embodiments, the cardiac electrical excitation activity is reconstructed using a regularization method.

[0092] This application fully utilizes the characteristics of biomagnetic signals and achieves dynamic three-dimensional source reconstruction calculation of cardiac magnetic signals throughout the entire cardiac cycle through spatial registration and signal processing technology.

[0093] The following provides a further explanation of step 131. In some embodiments, generating a dynamic distributed cardiac equivalent source model within the entire cardiac cycle based on the multi-frame dynamic images specifically includes:

[0094] Step 1311: Determine the template frame from the multi-frame dynamic images;

[0095] Step 1312: Based on the similarity between the template frame and other multi-frame dynamic images, register the diastolic and systolic images in the whole cardiac cycle to obtain the deformation field;

[0096] Step 1313: Place grid points in the three-dimensional space of the target space range corresponding to the template frame as the heart equivalent source distributed model of the template frame; wherein, the target space range is the region inside the pericardium and outside the heart chamber in the image;

[0097] Step 1314: Adjust the cardiac equivalent source distributed model of the template frame according to the deformation field to obtain the cardiac equivalent source distributed model corresponding to each frame of dynamic image, and then obtain the dynamic distributed cardiac equivalent source model in the whole cardiac cycle.

[0098] Specifically, in step 1311, a template frame is first determined from the multi-frame dynamic images obtained in step 110. The template frame can be any frame from the multi-frame dynamic images. In one specific embodiment, the segmented first frame image is used as the template frame.

[0099] In step 1312, based on the template frame, the diastolic and systolic images of the cardiac cycle are registered to obtain the deformation field. During the registration process, registration is performed based on the similarity between the template frame and other multiple dynamic images. In specific implementations, registration based on the similarity between the template frame and other multiple dynamic images includes various methods, such as torque and principal axis-based registration methods, intensity difference and correlation-based registration methods, and mutual information-based registration methods.

[0100] Among them, the torque- and principal axis-based registration methods use statistical factors derived from image data to calculate similarity and then perform image registration. Torque describes the spatial distribution of image quality (intensity). The torque-based registration method registers the image by aligning the torques in the image, while the principal axis-based method registers the image by aligning the principal axes of the inertia tensors of corresponding objects in the image.

[0101] Intensity difference and correlation registration methods attempt to determine the optimal registration scheme by maximizing the similarity between images that differ primarily due to different image acquisition conditions (such as noise). These methods typically assume that pixel values ​​in the registered images are strongly correlated.

[0102] Mutual information, as referred to in registration methods based on mutual information, is an information-theoretic metric used to measure the statistical dependence between two random variables, or the amount of information one variable contains about another. Mutual information can be qualitatively viewed as a measure of how well one image explains another. Mutual information is maximized for optimal alignment.

[0103] Furthermore, to facilitate calculation, similarity can be calculated by extracting only the most distinct image voxels from multiple frames of dynamic images.

[0104] In step 1313, grid points are placed in the three-dimensional space (target space range) within the pericardium and outside the heart cavity corresponding to the template frame, serving as the heart-equivalent source distributed model of the template frame. It should be noted that this application does not limit the grid spacing; it can be set according to computational efficiency. However, it is understood that setting the grid spacing too large is inappropriate. In one specific embodiment, the grid spacing is 5mm.

[0105] In step 1314, the cardiac equivalent source distributed model of the template frame is adjusted according to the deformation field to obtain the cardiac equivalent source distributed model corresponding to each frame image. The cardiac equivalent source distributed models corresponding to the dynamic images of all frames collectively constitute the dynamic distributed cardiac equivalent source model within the whole cardiac cycle.

[0106] This application embodiment transforms multi-frame dynamic images into a dynamic distributed cardiac equivalent source model within the entire cardiac cycle, serving as the basis for signal integration.

[0107] The following further explains step 133. In some embodiments, the step of calculating and reconstructing cardiac electrical excitation activity based on the magnetic field signal and the dynamic lead field matrix to obtain the calculation and reconstruction result specifically includes:

[0108] Based on the minimum residual principle, a cost function is constructed based on the residual term and the regularization term corresponding to the regularization constraint; wherein, the residual term is the difference between the magnetic field signal and the simulated data obtained by forward calculation through the dynamic lead field matrix;

[0109] Minimize the cost function to obtain the activity changes of each source in the source model after reconstruction as the calculation reconstruction result.

[0110] Specifically, based on the magnetic field signal obtained in step 110 and the dynamic lead field matrix obtained in step 132, the cardiac electrical excitation activity is reconstructed by minimizing the cost function. The reconstructed activity change of each source in the source model is the calculation and reconstruction result. In one embodiment, the calculation and reconstruction result is shown in Figure 4.

[0111] It should be explained that the cost function is constructed by combining the residual term, which is the difference between the measured data of the magnetocardiogram signal and the simulated data obtained by forward calculation through the lead field matrix, and the regularization term corresponding to the regularization constraint, based on the principle of minimum residual.

[0112] In one specific embodiment, the cost function is represented by a first preset formula.

[0113] First preset formula:

[0114] Here, L(S) is the cost function for solving the inverse problem. The solution to the inverse problem can be obtained by minimizing L(S). Where || || F This indicates that the F-norm of the data is to be calculated, where X is the matrix of magnetic field measurement data, G is the forward guiding field matrix obtained by finite element or boundary element methods, S is the distribution matrix of the source to be solved, λ represents the regularization parameter, and f(S) represents the regularization term (generally the noise covariance matrix).

[0115] This application embodiment will utilize spatial registration and signal processing technology to fully leverage the characteristics of biomagnetic signals to accurately reconstruct the four-dimensional representation of the heart.

[0116] Furthermore, in some embodiments, the four-dimensional visualization image includes at least one of a cardiac current density distribution change map, a cardiac activation and recovery map, and a cardiac activity main frequency distribution map.

[0117] Specifically, the four-dimensional visualization image may include a cardiac current density distribution map, as shown in Figure 5, where different colors represent different activation intensities. Simultaneously, the four-dimensional visualization image may also include a cardiac activation and recovery map, as shown in Figure 6, where different colors represent different activation times. Furthermore, the four-dimensional visualization image may also include a cardiac activity dominant frequency distribution map, as shown in Figure 7, where different colors represent different activation response frequencies.

[0118] This application provides a four-dimensional cardiac functional imaging method based on biomagnetic signals. It acquires the magnetic resonance imaging (MRI) signals of the subject and the dynamic structural information of the target trunk during the entire cardiac cycle. The target trunk includes at least the lungs, trunk, heart chambers, and pericardial structures. The dynamic structural information includes contour structures and multiple dynamic images. Spatial registration is performed between the dynamic structural information and the sensor acquiring the MRI signals to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information. Based on the dynamic structural information, the sensor coordinates, and the MRI signals, cardiac electrical excitation activity is calculated and reconstructed to obtain the calculation and reconstruction result. The calculation and reconstruction result is then converted into a four-dimensional visualized image. This application combines cardiac magnetic imaging and cardiac motion. Based on the acquired dynamic structural information and MRI signals, it fully utilizes the characteristics of biomagnetic signals and integrates signal processing technology through spatial registration to achieve accurate reconstruction and visualization of the four-dimensional representation of the heart and its functional activities. This results in a four-dimensional visualized image that comprehensively represents the dynamic electrophysiological activities of the entire heart (including the epicardium, endocardium, and intramural tissues) throughout the cardiac cycle, providing a novel technical solution for non-invasive imaging of cardiac electrical excitation activity.

[0119] The following describes the four-dimensional cardiac function imaging device based on biomagnetic signals provided in this application. The four-dimensional cardiac function imaging device based on biomagnetic signals described below can be referred to in conjunction with the four-dimensional cardiac function imaging method based on biomagnetic signals described above. As shown in Figure 8, the device includes:

[0120] The structural information acquisition module 810 is used to acquire the dynamic structural information of the target trunk of the test object during the entire cardiac cycle; wherein, the target trunk includes at least the two lungs, trunk and its heart chambers and pericardial structures, and the dynamic structural information includes contour structure and multiple frames of dynamic images;

[0121] The magnetic signal acquisition module 820 is used to acquire the magnetic signal of the subject under test.

[0122] The three-dimensional spatial registration module 830 is used to perform spatial registration between the dynamic structural information and the sensor that acquires the magnetocardiogram signal, so as to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information;

[0123] The data processing module 840 is used to calculate and reconstruct cardiac electrical excitation activity based on the dynamic structural information, the coordinates of the sensor, and the magnetic signal, and obtain the calculation and reconstruction result;

[0124] The four-dimensional visualization module 850 is used to convert the calculated reconstruction results into a four-dimensional visualization image.

[0125] According to the four-dimensional cardiac functional imaging device based on biomagnetic signals provided in this application, the step of calculating and reconstructing cardiac electrical excitation activity based on the dynamic structural information, the coordinates of the sensor, and the cardiac magnetic signals to obtain the calculation and reconstruction result specifically includes:

[0126] A dynamic distributed cardiac equivalent source model is generated based on the multi-frame dynamic images throughout the entire cardiac cycle;

[0127] The dynamic lead field matrix is ​​calculated based on the dynamic distributed cardiac equivalent source model, the coordinates of the sensor, and the contour structure.

[0128] Based on the said magnetic signal and the said dynamic lead field matrix, the cardiac electrical excitation activity is reconstructed, and the reconstruction result is obtained.

[0129] According to the four-dimensional cardiac function imaging device based on biomagnetic signals provided in this application, the step of spatially registering the dynamic structural information and the sensor acquiring the cardiac magnetic signals to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information specifically includes:

[0130] Each surface imaging marker is marked with its first spatial coordinate in the coordinate system of the dynamic structural information, and each magnetocardiogram measurement marker is recorded with its second spatial coordinate in the digital coordinate system using a digital measuring device; wherein, the surface imaging marker is a preset number of markers set on the torso of the subject during the acquisition of the dynamic structural information, and the magnetocardiogram measurement marker is the preset number of markers set on the torso of the subject during the measurement of the magnetocardiogram signal, and the positions of the preset number of surface imaging markers and the preset number of magnetocardiogram measurement markers correspond one-to-one, and the preset number is at least 4;

[0131] Align the first spatial coordinates and the second spatial coordinates according to the consistent position of the surface angiography markers and the magnetocardiography markers to obtain the transformation matrix between the coordinate system of the dynamic structural information and the digital coordinate system;

[0132] The sensor position is obtained by calculating the relative position of the magnetocardiogram signal sensor with respect to the magnetocardiogram measurement marker;

[0133] The coordinates of the sensor in the coordinate system of the dynamic structure information are obtained based on the sensor position and the transformation matrix.

[0134] According to the four-dimensional cardiac functional imaging device based on biomagnetic signals provided in this application, the step of generating a dynamic distributed cardiac equivalent source model throughout the entire cardiac cycle based on the multi-frame dynamic images specifically includes:

[0135] Determine the template frame from the multi-frame dynamic images;

[0136] Based on the similarity between the template frame and other multi-frame dynamic images, the diastolic and systolic images in the whole cardiac cycle are registered to obtain the deformation field;

[0137] Grid points are placed in the three-dimensional space corresponding to the target space range of the template frame to serve as the heart equivalent source distributed model of the template frame; wherein, the target space range is the region inside the pericardium and outside the heart chamber in the image;

[0138] The cardiac equivalent source distributed model of the template frame is adjusted according to the deformation field to obtain the cardiac equivalent source distributed model corresponding to each frame of dynamic image, and then the dynamic distributed cardiac equivalent source model within the whole cardiac cycle is obtained.

[0139] According to the four-dimensional cardiac functional imaging device based on biomagnetic signals provided in this application, the step of calculating and reconstructing cardiac electrical excitation activity based on the cardiac magnetic signals and the dynamic lead field matrix to obtain the calculation and reconstruction results specifically includes:

[0140] Based on the minimum residual principle, a cost function is constructed based on the residual term and the regularization term corresponding to the regularization constraint; wherein, the residual term is the difference between the magnetic field signal and the simulated data obtained by forward calculation through the dynamic lead field matrix;

[0141] Minimize the cost function to obtain the activity changes of each source in the source model after reconstruction as the calculation reconstruction result.

[0142] According to the present application, a four-dimensional cardiac function imaging device based on biomagnetic signals is provided, wherein the four-dimensional visualization image includes at least one of a cardiac current density distribution change map, a cardiac activation and recovery map, and a cardiac activity main frequency distribution map.

[0143] This application provides a four-dimensional cardiac functional imaging device based on biomagnetic signals. It acquires the magnetic signals of the target body and the dynamic structural information of the target trunk during the entire cardiac cycle. The target trunk includes at least the lungs, trunk, heart chambers, and pericardial structures. The dynamic structural information includes contour structures and multiple dynamic images. Spatial registration is performed between the dynamic structural information and the sensor acquiring the magnetic signals to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information. Based on the dynamic structural information, the sensor coordinates, and the magnetic signals, cardiac electrical excitation activity is calculated and reconstructed to obtain the calculation and reconstruction result. The calculation and reconstruction result is then converted into a four-dimensional visualized image. This application combines cardiac magnetic imaging and cardiac motion. Based on the acquired dynamic structural information and magnetic signals, it fully utilizes the characteristics of biomagnetic signals and integrates signal processing technology through spatial registration to achieve accurate reconstruction and visualization of the four-dimensional representation of the heart and its functional activities. This results in a four-dimensional visualized image that completely represents the dynamic electrophysiological activities of the entire heart (including the epicardium, endocardium, and intramural tissues) during the cardiac cycle, providing a novel technical solution for non-invasive imaging of cardiac electrical excitation activity.

[0144] Figure 9 illustrates a schematic diagram of the physical structure of an electronic device. As shown in Figure 9, the electronic device may include: a processor 910, a communication interface 920, a memory 930, and a communication bus 940. The processor 910, communication interface 920, and memory 930 communicate with each other via the communication bus 940. The processor 910 can call logical instructions in the memory 930 to execute a four-dimensional cardiac functional imaging method based on biomagnetic signals. This method includes: acquiring the magnetic signal of the target object and the dynamic structural information of the target trunk position during the entire cardiac cycle; wherein the target trunk position includes at least the lungs, trunk, and its heart chambers and pericardium; the dynamic structural information includes contour structures and multiple frames of dynamic images; spatially registering the dynamic structural information and the sensor acquiring the magnetic signal to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information; calculating and reconstructing cardiac electrical excitation activity based on the dynamic structural information, the sensor coordinates, and the magnetic signal to obtain the calculated reconstruction result; and converting the calculated reconstruction result into a four-dimensional visualization image.

[0145] Furthermore, the logical instructions in the aforementioned memory 930 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0146] On the other hand, this application also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the four-dimensional cardiac functional imaging method based on biomagnetic signals provided by the above methods. The method includes: acquiring the magnetic signal of the subject and the dynamic structural information of the target trunk position during the entire cardiac cycle; wherein the target trunk position includes at least the lungs, trunk and its heart chambers and pericardial structures, and the dynamic structural information includes contour structures and multiple frames of dynamic images; spatially registering the dynamic structural information and the sensor acquiring the magnetic signal of the heart to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information; calculating and reconstructing cardiac electrical excitation activity based on the dynamic structural information, the coordinates of the sensor and the magnetic signal of the heart to obtain the calculation and reconstruction result; and converting the calculation and reconstruction result into a four-dimensional visualization image.

[0147] In another aspect, this application also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program is implemented to perform the four-dimensional cardiac functional imaging method based on biomagnetic signals provided by the methods described above. The method includes: acquiring the magnetic signal of the subject and the dynamic structural information of the target trunk position during the entire cardiac cycle; wherein the target trunk position includes at least the lungs, trunk and its heart chambers and pericardial structures, and the dynamic structural information includes contour structures and multiple frames of dynamic images; spatially registering the dynamic structural information and the sensor acquiring the magnetic signal of the heart to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information; calculating and reconstructing cardiac electrical excitation activity based on the dynamic structural information, the coordinates of the sensor and the magnetic signal of the heart to obtain the calculation and reconstruction result; and converting the calculation and reconstruction result into a four-dimensional visualization image.

[0148] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0149] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A four-dimensional cardiac functional imaging method based on biomagnetic signals, comprising: The magnetic signal of the subject under test and the dynamic structural information of the target trunk position during the whole cardiac cycle are acquired; wherein, the target trunk position includes at least the two lungs, trunk and its heart chambers and pericardial structure, and the dynamic structural information includes contour structure and multi-frame dynamic images; Spatial registration is performed between the dynamic structural information and the sensor acquiring the magnetocardiogram signal to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information; Based on the dynamic structural information, the coordinates of the sensor, and the magnetic field signal, the cardiac electrical excitation activity is reconstructed to obtain the reconstruction result; The calculated reconstruction results are then converted into a four-dimensional visualization image.

2. The four-dimensional cardiac function imaging system based on biomagnetic signals according to claim 1, wherein, The step of calculating and reconstructing cardiac electrical excitation activity based on the dynamic structural information, the coordinates of the sensor, and the magnetic field signal to obtain the calculation and reconstruction result specifically includes: A dynamic distributed cardiac equivalent source model is generated based on the multi-frame dynamic images throughout the entire cardiac cycle; The dynamic lead field matrix is ​​calculated based on the dynamic distributed cardiac equivalent source model, the coordinates of the sensor, and the contour structure. Based on the said magnetic signal and the said dynamic lead field matrix, the cardiac electrical excitation activity is reconstructed, and the reconstruction result is obtained.

3. The four-dimensional cardiac function imaging system based on biomagnetic signals according to claim 1, wherein, The step of spatially registering the dynamic structural information and the sensor acquiring the magnetocardiogram signal to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information specifically includes: Each surface imaging marker is marked with its first spatial coordinate in the coordinate system of the dynamic structural information, and each magnetocardiogram measurement marker is recorded with its second spatial coordinate in the digital coordinate system using a digital measuring device; wherein, the surface imaging marker is a preset number of markers set on the torso of the subject during the acquisition of the dynamic structural information, and the magnetocardiogram measurement marker is the preset number of markers set on the torso of the subject during the measurement of the magnetocardiogram signal, and the positions of the preset number of surface imaging markers and the preset number of magnetocardiogram measurement markers correspond one-to-one, and the preset number is at least 4; Align the first spatial coordinates and the second spatial coordinates according to the consistent position of the surface angiography markers and the magnetocardiography markers to obtain the transformation matrix between the coordinate system of the dynamic structural information and the digital coordinate system; The sensor position is obtained by calculating the relative position of the magnetocardiogram signal sensor with respect to the magnetocardiogram measurement marker; The coordinates of the sensor in the coordinate system of the dynamic structure information are obtained based on the sensor position and the transformation matrix.

4. The four-dimensional cardiac function imaging system based on biomagnetic signals according to claim 2, wherein, The step of generating a dynamic distributed cardiac equivalent source model throughout the entire cardiac cycle based on the multi-frame dynamic images specifically includes: Determine the template frame from the multi-frame dynamic images; Based on the similarity between the template frame and other multi-frame dynamic images, the diastolic and systolic images in the whole cardiac cycle are registered to obtain the deformation field; Grid points are placed in the three-dimensional space corresponding to the target space range of the template frame to serve as the heart equivalent source distributed model of the template frame; wherein, the target space range is the region inside the pericardium and outside the heart chamber in the image; The cardiac equivalent source distributed model of the template frame is adjusted according to the deformation field to obtain the cardiac equivalent source distributed model corresponding to each frame of dynamic image, and then the dynamic distributed cardiac equivalent source model within the whole cardiac cycle is obtained.

5. The four-dimensional cardiac function imaging system based on biomagnetic signals according to claim 2, wherein, The process of calculating and reconstructing cardiac electrical excitation activity based on the magnetic field signal and the dynamic lead field matrix to obtain the calculation and reconstruction results specifically includes: Based on the minimum residual principle, a cost function is constructed based on the residual term and the regularization term corresponding to the regularization constraint; wherein, the residual term is the difference between the magnetic field signal and the simulated data obtained by forward calculation through the dynamic lead field matrix; Minimize the cost function to obtain the activity changes of each source in the source model after reconstruction as the calculation reconstruction result.

6. The four-dimensional cardiac function imaging system based on biomagnetic signals according to claim 1, wherein, The four-dimensional visualization image includes at least one of the following: a cardiac current density distribution change map, a cardiac activation and recovery map, and a cardiac activity main frequency distribution map.

7. A four-dimensional cardiac function imaging device based on biomagnetic signals, comprising: The structural information acquisition module is used to acquire the dynamic structural information of the target trunk of the test object during the entire cardiac cycle; wherein, the target trunk includes at least the two lungs, trunk and its heart chambers and pericardial structures, and the dynamic structural information includes contour structure and multi-frame dynamic images; A magnetic signal acquisition module is used to acquire the magnetic signal of the subject under test; A three-dimensional spatial registration module is used to perform spatial registration between the dynamic structural information and the sensor that acquires the magnetocardiogram signal, so as to obtain the coordinates of the sensor in the coordinate system of the dynamic structural information; The data processing module is used to calculate and reconstruct cardiac electrical excitation activity based on the dynamic structural information, the coordinates of the sensor, and the magnetic signal, and obtain the calculation and reconstruction results; The four-dimensional visualization module is used to convert the calculation and reconstruction results into four-dimensional visualization images.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein, When the processor executes the computer program, it implements the four-dimensional cardiac functional imaging method based on biomagnetic signals as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, wherein, When the computer program is executed by the processor, it implements the four-dimensional cardiac functional imaging method based on biomagnetic signals as described in any one of claims 1 to 6.

10. A computer program product comprising a computer program, wherein, When the computer program is executed by the processor, it implements the four-dimensional cardiac functional imaging method based on biomagnetic signals as described in any one of claims 1 to 6.

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