Magnetic resonance image rearrangement method, system and storage medium

Abstract

The present application relates to the field of magnetic resonance imaging technology. The present application discloses a magnetic resonance image rearrangement method, system and storage medium, which can improve the quality of magnetic resonance imaging. The method includes acquiring a PPG signal of the face; acquiring an SCG signal of the heart while acquiring the PPG signal; taking the time point corresponding to the positive peak value of each cycle in the SCG signal as the first trigger point; generating a corresponding first trigger signal based on each first trigger point, and sending all the first trigger signals to the magnetic resonance device to trigger it to perform an image acquisition operation to obtain multiple initial images; performing compensation calculation on the abnormal positive peak value in the SCG signal based on the PPG signal and the individual model to obtain at least one second trigger point; generating a corresponding second trigger signal based on all the first trigger points and all the second trigger points, and sending all the second trigger signals to the magnetic resonance device to trigger it to perform a rearrangement operation on the multiple initial images to obtain a target image set.

Description

Technical Field

[0001] The present application relates to the field of magnetic resonance imaging technology, and more specifically, to a magnetic resonance image rearrangement method, system and storage medium. Background Art

[0002] Cardiovascular Magnetic Resonance Imaging (CMRI) is a non-invasive medical imaging technology that can provide high-resolution cardiovascular images for evaluating cardiac structure and function, as well as related vascular systems such as the aorta and coronary arteries, providing important support for the diagnosis and treatment of cardiovascular diseases. Heart, respiratory and limb movements can cause artifacts in CMR (or CMRI) imaging. The main reason is that movement causes changes in tissue position and shape, causing image phase encoding errors or geometric deformation, and ultimately leading to image blur, ghosting, stripes or flickering. In order to alleviate the impact of motion artifacts on imaging, existing technologies often use gating technology to reduce interference. Gating technology uses external signals to trigger image acquisition, so that image acquisition is synchronized with the heart cycle, thereby achieving the purpose of reducing cardiac periodic motion artifacts. The current mainstream cardiac gating technologies are electrocardiogram (ECG) gating and pulse wave (PPG) gating. However, these two gating technologies still have defects, as follows:

[0003] The operation of ECG gating is extremely complicated and requires professional technicians to operate, which increases the burden on medical resources and limits the promotion of CMRI in primary medical institutions. In addition, ECG gating technology is easily interfered by the "hydromagnetic effect", that is, the behavior of water molecules in the magnetic field (such as flow speed, distribution, etc.) changes, which will affect the stability and accuracy of the ECG signal. Due to the interference of the "hydromagnetic effect", artifacts increase and image quality is reduced.

[0004] PPG gating is based on the large conduction time difference between the peripheral pulse wave signal and the R wave peak of ECG. Due to this conduction time difference, PPG gating technology has a significant trigger delay, causing MRI scans to be performed at different time points, and unable to accurately capture the specific movement state of the heart or other organs, resulting in increased artifacts and reduced image quality. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a magnetic resonance image rearrangement method, system and storage medium, which can reduce cardiac motion artifacts and improve the quality of magnetic resonance imaging. The embodiments of the present application are mainly implemented through the following technical solutions:

[0006] A first aspect of an embodiment of the present application provides a magnetic resonance image rearrangement method, comprising:

[0007] Get the PPG signal of the face;

[0008] While acquiring the PPG signal, acquiring the SCG signal of the heart;

[0009] The time point corresponding to the positive peak value of each waveform period in the SCG signal is taken as the first trigger point;

[0010] generating a corresponding first trigger signal based on each of the first trigger points, and sending all the first trigger signals to a magnetic resonance device of the magnetic resonance image rearrangement system to trigger the magnetic resonance device to perform an image acquisition operation to obtain a plurality of initial images;

[0011] Perform compensation calculation on the abnormal positive peak in the SCG signal based on the PPG signal and the individual model to obtain at least one second trigger point;

[0012] A corresponding second trigger signal is generated based on all the first trigger points and all the second trigger points, and all the second trigger signals are sent to the magnetic resonance device to trigger the magnetic resonance device to perform a rearrangement operation on the multiple initial images to obtain a target image set.

[0013] According to one embodiment of the present application, the step of acquiring the facial PPG signal includes:

[0014] receiving a first image sequence transmitted by a first camera of the magnetic resonance image reordering system;

[0015] Perform 0.5 Hz-4 Hz bandpass filtering on the G channel image sequence corresponding to the first image sequence to obtain a first waveform signal to be processed;

[0016] Performing detrending processing on the first waveform signal to be processed to obtain a second waveform signal to be processed;

[0017] Perform waveform normalization processing on the second waveform signal to be processed to obtain the PPG signal.

[0018] According to one embodiment of the present application, the step of acquiring the SCG signal of the heart while acquiring the PPG signal includes:

[0019] receiving a second image sequence transmitted by a second camera of the magnetic resonance image reordering system;

[0020] Calculating the motion amplitude of each speckle image in the second image sequence in the X direction and the motion amplitude in the Y direction by using the optical flow method, cascading the motion amplitudes of all speckle images in the X direction into a motion amplitude sequence in the X direction, and cascading the motion amplitudes of all speckle images in the Y direction into a motion amplitude sequence in the Y direction; calculating the motion angle based on the motion amplitude sequence in the X direction and the motion amplitude sequence in the Y direction;

[0021] obtaining an initial signal based on the movement angle;

[0022] The initial signal is preprocessed to obtain the SCG signal.

[0023] According to one embodiment of the present application, the step of preprocessing the initial signal to obtain the SCG signal includes:

[0024] removing the waveform trend of the initial signal to obtain a third waveform signal to be processed;

[0025] The third waveform signal to be processed is subjected to waveform amplitude normalization processing to obtain the SCG signal.

[0026] According to one embodiment of the present application, the magnetic resonance image rearrangement method further includes a step of constructing the individual model, and the step of constructing the individual model includes:

[0027] Set the first regression coefficient, the second regression coefficient, the third regression coefficient, the fourth regression coefficient and the error term;

[0028] A third trigger point is set in each waveform period of the PPG signal;

[0029] Obtain the heart rate, heart rate variability and heart beat interval of the target third trigger point;

[0030] constructing the individual model based on the first regression coefficient, the second regression coefficient, the third regression coefficient, the fourth regression coefficient, the error term, the heart rate, the heart rate variability, and the heart beat interval;

[0031] The target third trigger point is any third trigger point among all the third trigger points, and the individual model is used to output the time difference corresponding to the target third trigger point.

[0032] According to one embodiment of the present application, the step of performing compensation calculation on the abnormal positive peak in the SCG signal based on the PPG signal and the individual model to obtain at least one second trigger point includes:

[0033] Evaluate the PPG signal and the SCG signal to obtain an evaluation result;

[0034] When the evaluation result is that the PPG signal meets the first preset condition, the SCG signal does not meet the second preset condition, and the individual model is in an available state, the following steps are performed:

[0035] Using the individual model to estimate the time difference corresponding to the third trigger point of the target;

[0036] The time difference and the time point corresponding to the target third trigger point are used to perform a difference calculation to obtain a first time point to be processed on the SCG signal that is in the same cycle time as the target third trigger point;

[0037] A target time point is obtained based on the first time point to be processed and the SCG signal, and the target time point is used as the second trigger point.

[0038] According to one embodiment of the present application, the calculation formula for the step of performing difference calculation using the time difference and the time point corresponding to the target third trigger point to obtain the first to-be-processed time point on the SCG signal in the same cycle time as the target third trigger point is:

[0039] ;

[0040] in, is the first time point to be processed; The time point corresponding to the third trigger point of the target; is the time difference; is the index of the third trigger point of the target, i.e. A third trigger point.

[0041] A second aspect of an embodiment of the present application provides a magnetic resonance image rearrangement system, comprising:

[0042] A PPG signal acquisition module, used to acquire the PPG signal of the face;

[0043] An SCG signal acquisition module, used to acquire an SCG signal of the heart while acquiring the PPG signal;

[0044] A first trigger point acquisition module, used to take the time point corresponding to the positive peak value of each waveform period in the SCG signal as the first trigger point;

[0045] A first trigger signal generating module, configured to generate a corresponding first trigger signal based on each of the first trigger points, and send all the first trigger signals to a magnetic resonance device of the magnetic resonance image rearrangement system to trigger the magnetic resonance device to perform an image acquisition operation to obtain a plurality of initial images;

[0046] a compensation calculation module, configured to perform compensation calculation on the abnormal positive peak in the SCG signal based on the PPG signal and the individual model to obtain at least one second trigger point;

[0047] A second trigger signal generating module is used to generate corresponding second trigger signals based on all the first trigger points and all the second trigger points, and send all the second trigger signals to the magnetic resonance device to trigger the magnetic resonance device to rearrange the multiple initial images to obtain a target image set.

[0048] According to a third aspect of the embodiments of the present application, a magnetic resonance image rearrangement system is provided, comprising: a memory, a processor, a magnetic resonance device, a first camera, a second camera, a laser, and a signal generator, wherein the memory is used to store a computer program, the processor is used to call and run the computer program stored in the memory, and execute the steps of the magnetic resonance image rearrangement method, the magnetic resonance device, the first camera, and the second camera are all connected to the processor in communication, the first camera and the second camera are all connected to the signal generator in communication, and the laser is arranged on one side of the second camera;

[0049] The signal generator is used to send a synchronization signal to the first camera and the second camera;

[0050] The first camera is used to receive the synchronization signal, and based on the synchronization signal, start an image acquisition operation on the skin on the face to obtain a first image sequence, and transmit the first image sequence to the processor;

[0051] The second camera is used to receive the synchronization signal, and start an image acquisition operation on the heart part based on the synchronization signal to obtain a second image sequence, and transmit the second image sequence to the processor;

[0052] When the second camera performs an image acquisition operation on the heart area, the laser emits laser light to irradiate the heart area.

[0053] According to a fourth aspect of an embodiment of the present application, a computer-readable storage medium is provided, wherein the computer-readable storage medium is used to store a computer program, wherein the computer program enables a computer to execute the steps of the magnetic resonance image rearrangement method provided in the first aspect of the embodiment of the present application.

[0054] The beneficial effects of the embodiments of the present application include:

[0055] The embodiment of the present application uses the time point corresponding to the positive peak value of each waveform cycle in the SCG signal of the heart as the first trigger point to achieve accurate and efficient cardiac motion capture. Then, a corresponding first trigger signal is generated based on each first trigger point, and all first trigger signals are sent to the magnetic resonance device of the magnetic resonance image rearrangement system to trigger the magnetic resonance device to perform image acquisition operations and obtain multiple initial images, thereby achieving the effect of reducing cardiac motion artifacts. Then, based on the individual model and the PPG signal of the face acquired at the same time as the SCG signal, the abnormal positive peak value in the SCG signal is compensated and calculated to obtain at least one second trigger point to further improve the accuracy of cardiac motion capture; then, corresponding second trigger signals are generated based on all first trigger points and all second trigger points, and all second trigger signals are sent to the magnetic resonance device to trigger the magnetic resonance device to perform rearrangement operations on multiple initial images to obtain a target image set, thereby ensuring the stability of the first trigger point and the second trigger point, and further reducing cardiac motion artifacts. Therefore, compared with the prior art, the embodiment of the present application can achieve accurate and efficient cardiac motion capture, reduce cardiac motion artifacts, and improve the quality of magnetic resonance imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0057] Figure 1 For this application, a clear image that is not affected by motion;

[0058] Figure 2 For Figure 1 Artifact images affected by motion at the same location;

[0059] Figure 3 For this application, a clear image that is not affected by motion;

[0060] Figure 4 For Figure 3 Artifact images affected by motion at the same location;

[0061] Figure 5 For this application, a clear image that is not affected by motion;

[0062] Figure 6 For Figure 5 Artifact images affected by motion at the same location;

[0063] Figure 7This is a reference image of an ECG signal that is less affected by the "hydromagnetic effect";

[0064] Figure 8 This is a reference image of an ECG signal moderately disturbed by the "hydromagnetic effect";

[0065] Fig. 9 This is a reference image of an ECG signal that is strongly interfered by the "hydromagnetic effect";

[0066] Fig.10 This is a reference diagram for the presence of trigger delay in the PPG signal;

[0067] Fig.11 Reference images obtained for PPG signals and SCG signals;

[0068] Fig.12 is the reference image of the PPG signal;

[0069] Fig.13 is the reference image of SCG signal;

[0070] Fig.14 A flowchart of a magnetic resonance image rearrangement method in some embodiments;

[0071] Fig.15 is the reference image of SCG signal;

[0072] Fig.16 is the reference image of the PPG signal;

[0073] Fig.17 A flowchart of the magnetic resonance image rearrangement method of the present application in some other embodiments;

[0074] Fig.18 It is a reference image of PPG signal and SCG signal;

[0075] Fig.19 A reference image of the speckle image captured by the second camera;

[0076] Fig. 20 A schematic block diagram of a magnetic resonance image rearrangement system in some embodiments;

[0077] Fig.21 It is a principle block diagram of a magnetic resonance image rearrangement system in some other embodiments. DETAILED DESCRIPTION

[0078] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0079] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0080] The terms "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0081] The terms "comprises," "includes," or any other variations thereof are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or apparatus that comprises a series of steps or elements is not necessarily limited to those steps or elements explicitly listed but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0082] Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in the specification of this application includes any and all combinations of one or more related listed items.

[0083] Cardiovascular Magnetic Resonance Imaging (CMRI) is a non-invasive medical imaging technology that can provide high-resolution cardiovascular images for evaluating cardiac structure and function, as well as related vascular systems such as the aorta and coronary arteries, providing important support for the diagnosis and treatment of cardiovascular diseases. Heart, respiratory and limb movements can cause artifacts in CMR (or CMRI) imaging. The main reason is that movement causes changes in tissue position and shape, causing image phase encoding errors or geometric deformation, and ultimately leading to image blur, ghosting, streaks or flickering. For example, you can refer to Figure 1-6 As shown, Figure 1 , Figure 3 and Figure 5 All are clear images that are not affected by motion. Figure 2 is with Figure 1 Artifact images affected by motion at the same location, Figure 4 For Figure 3 Artifact images affected by motion at the same location, Figure 6 For Figure 5 Artifact images affected by motion in the same part. In order to alleviate the impact of motion artifacts on imaging, existing technologies often use gating technology to reduce interference. Gating technology uses external signals to trigger image acquisition, so that image acquisition is synchronized with the heart cycle, thereby achieving the purpose of reducing cardiac periodic motion artifacts. The current mainstream cardiac gating technologies include electrocardiogram (ECG) gating and pulse wave (PPG) gating. Among them, ECG gating requires accurate positioning of typical feature points on the ECG signal waveform (such as the R wave peak). For example, in prospective gating, when the R wave peak feature point or other waveform feature points (such as P wave, T wave peak) appear and are detected, the magnetic resonance device is immediately triggered to scan; in retrospective gating, all waveform feature points are recorded, and after the scanning operation is completed, the magnetic resonance data is reordered according to the recorded waveform feature points, grouped or associated with different stages of the cardiac motion cycle to construct accurate cardiac movie motion. However, these two gating technologies still have defects, as follows:

[0084] ECG gating is extremely complex and requires professional technicians to operate, which increases the burden on medical resources and limits the promotion of CMRI in primary medical institutions. In addition, ECG gating technology is easily affected by the "hydromagnetic effect", that is, the behavior of water molecules in the magnetic field (such as flow speed, distribution, etc.) changes, which will affect the stability and accuracy of the ECG signal. For example, ECG signals that are less affected by the "hydromagnetic effect" can be referred to Figure 7As shown, the ECG signal moderately disturbed by the "hydromagnetic effect" can be referred to Figure 8 As shown, ECG signals that are strongly disturbed by the "hydromagnetic effect" can be referred to Fig. 9 As shown in the figure, due to the interference of "hydromagnetic effect", the number of artifacts increases and the image quality is reduced.

[0085] PPG gating is based on the large conduction time difference between the peripheral pulse wave signal and the R wave peak of the ECG. Due to this conduction time difference, PPG gating technology has a significant trigger delay, see Fig.10 As shown, during one cardiac cycle, there is a "delay" between the trigger point pointed to by the ECG-R wave in the ECG signal and the trigger point pointed to by the PPG contraction period in the PPG signal. This "delay" will cause the MRI scan to be performed at different time points and fail to accurately capture the specific movement state of the heart or other organs, resulting in increased artifacts and reduced image quality. In addition, contact-type gating devices may cause discomfort to patients during CMRI examinations due to the requirement for fixed body positions, especially for patients with sensitive skin or special medical needs, which increases the inconvenience and complexity of the examination.

[0086] Although both ECG and PPG mentioned above have defects, the two can be used in combination to form composite gating (or multimodal gating). This combined method can take advantage of the independent monitoring of the two signals to improve the accuracy and reliability of MRI gating. The advantages of composite gating include: 1) Stronger reliability: When one signal (such as ECG or PPG) is affected by noise or artifacts, the other signal can provide backup support to ensure the stability of the gating signal; 2) Higher accuracy: Combining the precise cardiac cycle identification of ECG with the ease of use and comfort of PPG, more accurate gating information can be obtained in various environments; 3) Better adaptability: For specific patients or conditions, ECG and PPG signals can be dynamically selected or weighted as needed to obtain the best effect. Based on the combined use of ECG and PPG, the inventor innovatively proposed a magnetic resonance image rearrangement method to overcome the defects of ECG and PPG.

[0087] The magnetic resonance image rearrangement method uses PPG signals and SCG (Seismocardiography) signals to combine into a composite cardiovascular magnetic resonance gating, referring to Fig.11 As shown, it should be noted that Fig.11 Please refer to the PPG signal diagram in the upper right corner Fig.12 , Fig.11 Please refer to the SCG signal diagram in the lower right corner Fig.13 The composite cardiovascular magnetic resonance gating can provide more accurate and reliable waveform information for removing artifacts from nuclear magnetic resonance images.

[0088] exist Fig.12 and Fig.13 In the PPG waveform (also known as the PPG signal) and the SCG waveform (also known as the SCG signal) are similar to the ECG waveform, and are both periodic physiological signals. The SCG signal is obtained from the laser speckle image of the heart position. Compared with the PPG signal extracted from the face image, the SCG signal can reflect the heart movement information faster and more accurately. The characteristic points of the SCG signal (reference Fig.13 The trigger points and Fig.15 AO peak in the image) and PPG signal feature points (reference Fig.12 The trigger points and Fig.16 The trough before the mid-systolic period) is often detected by means of peak positioning or machine learning, and used as a trigger point signal for the magnetic resonance device to start scanning. Since the SCG signal needs to accurately position the laser to the fourth rib position in the lower left of the human chest (that is, the fourth rib position) to extract high-quality SCG signals, the stability of the SCG signal is weaker than that of the PPG signal. However, the time difference between the characteristic points of the SCG signal and the characteristic points of the PPG signal (this time difference is also called the pulse wave transmission time, or PTT) is relatively stable in a short period of time, and is strongly related to the human heart rate and physiological state at the current moment. Therefore, in the early stage of the magnetic resonance device scanning, the time difference and the current heart rate (HR, Heart Rate), heart beat interval (IBI, Inter-Beat Interval), heart rate variability (HRV, Heart Rate Variability) and other physiological information can be used for model regression (pre-learning) to quickly establish an individual model for each patient. When the SCG signal is abnormal, the SCG signal is compensated by the more stable PPG signal to estimate the trigger point of the lost SCG signal, which is used to trigger image rearrangement in retrospective MRI scanning.

[0089] Based on the above concept, the composite cardiovascular magnetic resonance gating of the present application uses a defocused camera and a laser to capture the weak cardiac vibrations in the chest to construct an SCG signal in prospective gating, locates the moment when the heart moves to the same position based on the SCG signal, and triggers the magnetic resonance device to acquire images, so as to achieve the effect of reducing cardiac motion artifacts; in retrospective gating, the characteristic points of all waveforms of the SCG signal and the PPG signal are recorded, and the PPG signal is used to compensate and estimate the SCG signal to trigger magnetic resonance image rearrangement.

[0090] More specifically, the specific implementation methods of the present application are further described in conjunction with the accompanying drawings.

[0091] like Fig.14FIG. 1 is a flowchart of a magnetic resonance image rearrangement method provided in the first aspect of the embodiment of the present application. Figure 1 In the method, the magnetic resonance image rearrangement method comprises:

[0092] S1. Obtain facial PPG signal.

[0093] Furthermore, the S1 step includes:

[0094] S11 , receiving a first image sequence transmitted by a first camera of the magnetic resonance image rearrangement system.

[0095] It should be understood that the first camera starts to perform image acquisition operation on the patient's face after receiving the synchronization signal sent by the signal generator in the magnetic resonance image rearrangement system, so as to obtain the first image sequence. More specifically, the first camera captures the skin area of ​​the patient's face. When the face has other areas besides the skin area, the first camera first performs the skin positioning operation and then starts to capture the first image sequence; when the face only includes the skin area, the positioning operation is not required.

[0096] The synchronization signal can ensure synchronous image acquisition operation between the first camera and the second camera. The synchronization signal is a periodic square wave with a frame rate not less than 200fps, and the high and low level values ​​are set according to the external signal requirements required by the first camera and the second camera.

[0097] S12, performing 0.5 Hz-4 Hz bandpass filtering on the G channel image sequence corresponding to the first image sequence to obtain a first waveform signal to be processed.

[0098] It should be understood that each image in the first image sequence includes RGB three-channel image data.

[0099] The G channel image sequence refers to a sequence formed by integrating information carried by the G channels of all images in the first image sequence.

[0100] S13, performing detrending processing on the first waveform signal to be processed to obtain a second waveform signal to be processed.

[0101] The step S13 can eliminate the trend item or long-term change in the first waveform signal to be processed.

[0102] S14. Perform waveform normalization processing on the second waveform signal to be processed to obtain the PPG signal.

[0103] The step S14 can adjust the amplitude range of the second waveform signal to be processed, so that the second waveform signal to be processed is easier to process and analyze, thereby improving the stability and reliability of the PPG signal.

[0104] S2. While acquiring the PPG signal, acquire the SCG signal of the heart.

[0105] It should be understood that the face and the heart area belong to the same patient.

[0106] Furthermore, the S2 step includes:

[0107] S21 , receiving a second image sequence transmitted by a second camera of the magnetic resonance image rearrangement system.

[0108] It should be understood that the second camera starts to perform image acquisition operations on the patient's heart area after receiving the synchronization signal sent by the signal generator, thereby obtaining the second image sequence.

[0109] Each image in the second image sequence is a speckle image.

[0110] S22. Calculate the motion amplitude of each speckle image in the second image sequence in the X direction and the motion amplitude in the Y direction by using the optical flow method, cascade the motion amplitudes of all speckle images in the X direction into a motion amplitude sequence in the X direction, and cascade the motion amplitudes of all speckle images in the Y direction into a motion amplitude sequence in the Y direction.

[0111] S23, calculating the motion angle based on the motion amplitude sequence in the X direction and the motion amplitude sequence in the Y direction.

[0112] Furthermore, the calculation formula of step S23 is:

[0113] ;

[0114] in, represents the main motion quadrant, which needs to be obtained from the four quadrants using the calculation formula in step S23. The purpose is that the actual motion of the speckle may be noisy, but the motion direction of the speckle motion caused by the heart is highly concentrated and located in one of the four quadrants; The representative selects the quadrant with the largest ninety-point value from the four quadrants and takes it as the main movement quadrant; Represents the ninetieth digit amplitude value in the corresponding quadrant; Represents the optical flow method calculated Directional optical flow, that is, the sequence of motion amplitudes in the X direction; Represents the optical flow method calculated Directional optical flow, that is, the sequence of motion amplitudes in the Y direction; Represents the current Axis coordinate position; Represents the current Coordinate location; represents the four quadrants in the Cartesian coordinate system, ; represents the angle of movement; represents the median; represents the tangent function; Representative Points in The integral value in the Y direction, that is, the first The integral value of each point; Representative Points in The integral value in the direction, that is, the first in the sequence of motion amplitudes in the X direction The integral value of each point; Representative Points in The coordinate position of the axis; Representative Points in The coordinate position of the axis.

[0115] In other implementations, PCA (Principal Component Analysis) or a maximum value method may be used to replace the ninetieth digit amplitude value to determine the main motion quadrant and the main motion angle (ie, the motion angle mentioned above).

[0116] S24. Obtain an initial signal based on the movement angle.

[0117] Furthermore, the calculation formula of step S24 is:

[0118] ;

[0119] in, represents the initial signal; represent Signal sequence, that is, the sequence of motion amplitudes in the entire X direction; represents the angle of movement; represent Signal sequence, that is, the sequence of motion amplitudes in the entire Y direction.

[0120] S25. Preprocess the initial signal to obtain the SCG signal.

[0121] The purpose of setting the step S25 is that differences in human body movements and clothing materials may cause different amplitude ranges and waveform noises to appear in the initial signal, and therefore, basic signal processing is required for the initial signal.

[0122] Furthermore, the step S25 includes:

[0123] S251. Remove the waveform trend of the initial signal to obtain a third waveform signal to be processed.

[0124] The step S251 can improve the accuracy and reliability of the initial signal.

[0125] S252, performing waveform amplitude normalization processing on the third waveform signal to be processed to obtain the SCG signal.

[0126] S3, taking the time point corresponding to the positive peak value of each waveform period in the SCG signal as the first trigger point. The step S3 can be understood as Fig.17 The "Starting point detection (peak location, machine learning, etc.)" step and the "SCG trigger point" step in the .

[0127] The embodiment of the present application uses machine learning technology to divide the SCG signal into different cardiac motion stages, each stage representing a different physiological state of the heart. Fig.15 As shown, in Fig.15 In the method, the signal corresponding to each waveform period in the SCG signal is divided into mitral valve closure (MC) stage, isovolumetric contraction (IVC) stage, aortic opening (AO) stage, rapid ejection (RE) stage, aortic valve closure (AC) stage, mitral valve opening (MO) stage and rapid filling (RF) stage.

[0128] In the prospective gating, the embodiment of the present application sets the positive peak value of the SCG signal (i.e. Fig.15 The time position (i.e., time point) at which the AO peak in the image appears is taken as the first trigger point.

[0129] S4. Generate a corresponding first trigger signal based on each of the first trigger points, and send all the first trigger signals to the magnetic resonance device of the magnetic resonance image rearrangement system to trigger the magnetic resonance device to perform an image acquisition operation to obtain a plurality of initial images.

[0130] S5. Perform compensation calculation on the abnormal positive peak in the SCG signal based on the PPG signal and the individual model to obtain at least one second trigger point.

[0131] The embodiment of the present application uses machine learning technology to divide the PPG signal into different cardiac motion stages, each stage representing a different physiological state of the heart. Fig.16 As shown, in Fig.16 In the embodiment of the present application, the signal corresponding to each waveform period in the PPG signal is divided into systole, dicrotic period and diastole. It should be understood that the "machine learning technology" mentioned in the embodiment of the present application can be a supervised learning algorithm, an unsupervised learning algorithm or a deep learning algorithm, which can be determined by those skilled in the art according to actual needs.

[0132] Furthermore, the step S5 includes:

[0133] S51, evaluate the PPG signal and the SCG signal to obtain an evaluation result. The PPG signal can refer to Fig.17 The SCG signal can be referred to in the "PPG waveform" step. Fig.17 The S51 step can refer to the "SCG waveform" step in Fig.17 "PPG, SCG waveform evaluation (heart rate range, signal-to-noise ratio, etc.)" step in

[0134] The S51 specifically evaluates the quality of the PPG signal and the SCG signal. For example, the quality of the PPG signal and the SCG signal may be evaluated by evaluating whether the current heart rate range is within the normal range of the human body (0.5 Hz-4 Hz) and whether the signal-to-noise ratio is higher than a set value.

[0135] The evaluation results include four evaluation results: the PPG signal meets the first preset condition and the SCG signal meets the second preset condition, the PPG signal does not meet the first preset condition and the SCG signal meets the second preset condition, the PPG signal meets the first preset condition and the SCG signal does not meet the second preset condition, and the PPG signal does not meet the first preset condition and the SCG signal does not meet the second preset condition.

[0136] It should be understood that the first preset condition is that the current heart rate range is within the normal range of the human body (0.5Hz-4Hz) and the signal-to-noise ratio is higher than a set value. The set value can be set by those skilled in the art according to actual needs.

[0137] The second preset condition is the same as the first preset condition.

[0138] S52: When the evaluation result shows that the PPG signal meets the first preset condition, the SCG signal does not meet the second preset condition, and the individual model is in an available state, perform the following steps S53, S54 and S55. The step S52 can be understood as Fig.17 The "Individual Model States" step in .

[0139] Furthermore, the magnetic resonance image rearrangement method further comprises the step of constructing the individual model, and the step of constructing the individual model comprises:

[0140] S521. Set a first regression coefficient, a second regression coefficient, a third regression coefficient, a fourth regression coefficient and an error term.

[0141] S522. Set a third trigger point in each waveform period of the PPG signal.

[0142] The third trigger point is set at the trough position before the contraction period in each waveform cycle. Fig.18 As shown, in Fig.18 In the embodiment, the third trigger point is expressed as "PPG trigger point". The step S522 can be understood as Fig.17 The "starting point detection (peak location, learning, etc.)" step and the "PPG trigger point" step in the process are as follows:

[0143] S523: Obtain the heart rate, heart rate variability, and heart beat interval of the target third trigger point.

[0144] S524. Constructing the individual model based on the first regression coefficient, the second regression coefficient, the third regression coefficient, the fourth regression coefficient, the error term, the heart rate, the heart rate variability and the heart beat interval; wherein the target third trigger point is any third trigger point among all the third trigger points, and the individual model is used to output the time difference corresponding to the target third trigger point (the time difference is also called pulse wave transmission time, i.e. PTT).

[0145] The step of constructing the individual model can be understood as Fig.17 The "Model Regression" and "User Individual Model" steps in .

[0146] Furthermore, the calculation formula of the individual model is:

[0147] ;

[0148] in, is the time difference corresponding to the third trigger point of the target, that is, the time difference of the first trigger point on the PPG signal The time difference corresponding to the trigger points; is the first regression coefficient; is the second regression coefficient; is the third regression coefficient; is the fourth regression coefficient; is the heart rate corresponding to the third trigger point of the target, that is, the heart rate of the third trigger point on the PPG signal The heart rate corresponding to each trigger point; is the heart rate variability corresponding to the target third trigger point, that is, the heart rate variability of the PPG signal Heart rate variability corresponding to each trigger point; is the heartbeat interval corresponding to the target third trigger point, that is, the heartbeat interval corresponding to the third trigger point on the PPG signal The heartbeat interval corresponding to each trigger point; is the error term.

[0149] When the error term satisfies the set range, the individual model is in an available state.

[0150] The setting range is less than 250 ms. In other implementations, the setting range is not limited to the aforementioned example, and can be determined by those skilled in the art according to actual needs.

[0151] S53, using the individual model to estimate the time difference corresponding to the third trigger point of the target. The time difference can refer to Fig.18 In , or The time difference can also be Fig.17 The "Trigger Point Time Difference" step in

[0152] S54, performing a difference calculation using the time difference and the time point corresponding to the target third trigger point to obtain a first time point to be processed on the SCG signal that is in the same cycle time as the target third trigger point. The time point corresponding to the target third trigger point can be referenced to Fig.18 In , or .

[0153] The first pending time point can refer to Fig.18 The time point corresponding to "SCG trigger point 1" in , or .

[0154] Furthermore, the calculation formula of step S54 is:

[0155] ;

[0156] in, is the first time point to be processed; The time point corresponding to the third trigger point of the target; is the time difference; is the index of the third trigger point of the target, i.e. A third trigger point.

[0157] S55, calculating a target time point based on the first time point to be processed and the SCG signal, and taking the target time point as the second trigger point. S55 can be understood as Fig.17 The "Estimating missing SCG trigger points" step in

[0158] The target time point can refer to Fig.18 The "SCG trigger point 2" in the figure is the positive peak value in each waveform cycle of the SCG signal.

[0159] Furthermore, the step S55 includes:

[0160] S551, select a signal segment of one waveform period in which there is no abnormal positive peak in the SCG signal. The signal segment is a normal and standard signal.

[0161] S552: Extract a second time point to be processed based on the signal segment and a time point corresponding to the positive peak value of the signal segment. The second maximum processing time point can refer to Fig.18 The time point corresponding to the "SCG trigger point 1" in the above diagram can be referred to as the time point corresponding to the positive peak of the signal segment. Fig.18 The time point corresponding to “SCG trigger point 2”.

[0162] S553: ​​Subtract the second largest processing time point from the time point corresponding to the positive peak value of the signal segment to obtain a time difference to be processed.

[0163] S554: Add the first to-be-processed time point and the to-be-processed time difference to obtain the target time point.

[0164] Furthermore, the step S5 further includes:

[0165] S56: When the evaluation result is that the PPG signal does not meet the first preset condition, re-execute the steps S1 and S2.

[0166] It should be understood that before re-executing the steps S1 and S2, it is first checked whether the magnetic resonance device is intact, and the positions of the first camera and the second camera are adjusted so that the PPG signal meets the first preset condition.

[0167] S57. When the evaluation result is that the PPG signal meets the first preset condition, the SCG signal does not meet the second preset condition, and the individual model is in an unavailable state or the individual model has not yet undergone model regression, the S1 and S2 steps are also re-executed.

[0168] S6, generating corresponding second trigger signals based on all the first trigger points and all the second trigger points, and sending all the second trigger signals to the magnetic resonance device to trigger the magnetic resonance device to rearrange the multiple initial images to obtain a target image set. The step S6 can refer to Fig.17 The "NMR" step in

[0169] The steps S5 and S6 can be understood as steps of the retrospective gating stage.

[0170] In the above implementation, the embodiment of the present application uses the time point corresponding to the positive peak value of each waveform cycle in the SCG signal of the heart as the first trigger point to achieve accurate and efficient cardiac motion capture, then generates a corresponding first trigger signal based on each first trigger point, and sends all the first trigger signals to the magnetic resonance device of the magnetic resonance image rearrangement system to trigger the magnetic resonance device to perform image acquisition operations and obtain multiple initial images, thereby achieving the effect of reducing cardiac motion artifacts. Then, based on the individual model and the PPG signal of the face acquired at the same time as the SCG signal, the abnormal positive peak value in the SCG signal is compensated and calculated to obtain at least one second trigger point to further improve the accuracy of cardiac motion capture; then, based on all the first trigger points and all the second trigger points, the corresponding second trigger signals are generated, and all the second trigger signals are sent to the magnetic resonance device to trigger the magnetic resonance device to perform rearrangement operations on multiple initial images to obtain a target image set, thereby ensuring the stability of the first trigger point and the second trigger point, and further reducing cardiac motion artifacts. Therefore, compared with the prior art, the embodiment of the present application can achieve accurate and efficient cardiac motion capture, reduce cardiac motion artifacts, and improve the quality of magnetic resonance imaging.

[0171] In some embodiments, the magnetic resonance image rearrangement method further comprises:

[0172] S7. Adjust a first position and a first shooting angle of the first camera.

[0173] The S7 step can adjust the first camera to capture a clear facial skin area to improve the accuracy of the PPG signal.

[0174] S8. Adjust the second position and the second shooting angle of the second camera, and adjust the third position and the irradiation angle of the laser of the magnetic resonance image rearrangement system.

[0175] In the embodiment of the present application, the laser of the laser irradiates the fourth rib position of the lower left chest cavity of the human body, and the defocus camera (that is, the second camera) takes the speckle image of the laser reflection when receiving the synchronization signal, and the periodic movement of the heart is constructed with high precision by analyzing the motion pattern of the laser speckle image. The interference speckle formed on the imaging plane of the second camera after the laser is reflected by the chest cavity significantly amplifies the heart vibration, realizes the accurate reconstruction of the heart vibration signal, and triggers the acquisition of CMR images based on the reconstructed SCG signal, or records the precise heart movement position.

[0176] Further, the focal length F of the lens of the second camera is adjusted until the focal plane of the second camera moves from the heart plane to a position L2 away from the camera lens (reference Fig.19 , the distance between the chest plane of the human body and the focal plane is L1, and the distance between the focal plane of the second camera and the lens is L2). At this time, a significantly magnified laser interference speckle image can be observed, and the speckle image will move regularly in the imaging plane with the regular beating of the heart. Fig.19 As shown, the defocus degree of the lens can be expressed by L1 / L2 (L1>L2 should be satisfied), thereby obtaining that the motion amplification gain of the reconstructed cardiac oscillation signal is approximately equal to the defocus degree of the lens.

[0177] The second camera captures laser speckle images at a frame rate of at least 200 fps and a resolution of 400×300 to obtain continuous speckle image frames, and the continuous speckle image frames are also the second image sequence.

[0178] refer to Fig. 20 FIG. 1 is a block diagram of a magnetic resonance image rearrangement system provided in the second aspect of the embodiment of the present application. Fig. 20 In the embodiment, the magnetic resonance image rearrangement system 100 comprises:

[0179] A PPG signal acquisition module 101, used to acquire a facial PPG signal;

[0180] An SCG signal acquisition module 102, configured to acquire an SCG signal of the heart while acquiring the PPG signal;

[0181] A first trigger point acquisition module 103, configured to use the time point corresponding to the positive peak value of each waveform period in the SCG signal as the first trigger point;

[0182] A first trigger signal generating module 104 is configured to generate a corresponding first trigger signal based on each of the first trigger points, and send all the first trigger signals to a magnetic resonance device of the magnetic resonance image rearrangement system to trigger the magnetic resonance device to perform an image acquisition operation to obtain a plurality of initial images;

[0183] A compensation calculation module 105, configured to perform compensation calculation on the abnormal positive peak in the SCG signal based on the PPG signal and the individual model to obtain at least one second trigger point;

[0184] The second trigger signal generating module 106 is used to generate corresponding second trigger signals based on all the first trigger points and all the second trigger points, and send all the second trigger signals to the magnetic resonance device to trigger the magnetic resonance device to rearrange the multiple initial images to obtain a target image set.

[0185] refer to Fig.21 FIG. 1 is a block diagram of a magnetic resonance image rearrangement system provided in the third aspect of the embodiment of the present application. Fig.21 In the embodiment, the magnetic resonance image rearrangement system 200 includes a memory 201, a processor 202, a magnetic resonance device 203, a first camera 204, a second camera 205, a laser 206 and a signal generator 207, wherein the memory 201 is used to store a computer program, the processor 202 is used to call and run the computer program stored in the memory 201, and execute the steps of the magnetic resonance image rearrangement method described above, the magnetic resonance device 203, the first camera 204 and the second camera 205 are all connected to the processor 202 for communication, the first camera 204 and the second camera 205 are all connected to the signal generator 207 for communication, and the laser 206 is arranged on one side of the second camera 205;

[0186] The signal generator 207 is used to send a synchronization signal to the first camera 204 and the second camera 205;

[0187] The first camera 204 is used to receive the synchronization signal and start an image acquisition operation on the skin on the face based on the synchronization signal to obtain a first image sequence (i.e. Fig.11 ), and transmit the first image sequence to the processor 202, referring to Fig.11 As shown;

[0188] The second camera 205 is used to receive the synchronization signal and start the image acquisition operation of the heart part based on the synchronization signal to obtain a second image sequence (i.e. Fig.11 and transmitting the second image sequence to the processor 202, referring to Fig.11 As shown;

[0189] When the second camera 205 performs an image acquisition operation on the heart area, the laser 206 emits laser (or laser light) to irradiate the heart area.

[0190] In the embodiment of the present application, the first camera 204, the second camera 205 and the laser 206 are installed at or near the outer circle of the scanning cavity of the magnetic resonance device 203 to capture the patient's face and all positions of the chest.

[0191] The first camera 204 is a focus camera, and the second camera 205 is a defocus camera.

[0192] Due to the arrangement of the first camera 204 and the second camera 205 , the embodiment of the present application has the advantages of non-contact, high precision, and robustness to magnetic fields, and can simultaneously realize reconstruction of heartbeat motion and respiratory motion.

[0193] The defocus camera allows cardiovascular magnetic resonance gating without contact with the human body. Its working principle is not affected by the strong magnetic field of MR (Magnetic Resonance), and can reconstruct the cardiac motion cycle (Camera-SCG, also known as the SCG signal) with high precision, and obtain heart and respiratory motion signals through speckle image processing; the focusing camera obtains the facial pulse wave signal (Camera-PPG, also known as the PPG signal) and the SCG signal to establish a personalized "pulse wave conduction time-blood pressure" correlation model, so that when an abnormal SCG waveform occurs in a retrospective scan, compensation estimation can be performed, thereby enhancing the detection rate and detection accuracy of the trigger point.

[0194] The laser emitted by the laser 206 may be lasers of different wavelength bands. The lasers of different wavelength bands are irradiated to different positions of the patient's chest plane. After the heartbeat movement is amplified by the defocus lens, different multi-band laser speckles are finally formed on the second camera 205. The speckle images of different wavelength bands can be obtained by separating the RGB channel data of the speckle image. The above-mentioned SCG signal extraction is performed on the laser speckle images of different wavelength bands, so that multi-channel heart vibration signals (i.e., SCG signals) from different chest positions can be extracted.

[0195] In some embodiments, the first camera 204, the second camera 205, the laser 206 and the signal generator 207 are used as a signal acquisition unit, and the processor 202 is used as a signal processing unit. Fig.11 The magnetic resonance image rearrangement method provided in the first aspect of the embodiment of the present application is run on the processor 202 .

[0196] According to a fourth aspect of an embodiment of the present application, a computer-readable storage medium is provided, wherein the computer-readable storage medium is used to store a computer program, wherein the computer program enables a computer to execute the steps of the magnetic resonance image rearrangement method provided in the first aspect of the embodiment of the present application.

[0197] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present invention can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0198] The technical features of the above embodiments can be combined without changing the basic principles of the present application. To make the description concise, 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.

[0199] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the scope of patent protection of the present application shall be subject to the attached claims.

Claims

1. A magnetic resonance image rearrangement method, characterized in that: include: Acquire a PPG signal of the face, wherein the PPG signal is a photoplethysmographic signal; While acquiring the PPG signal, acquiring an SCG signal of the heart, wherein the SCG signal is a seismic cardiography signal; The time point corresponding to the positive peak value of each waveform period in the SCG signal is taken as the first trigger point; generating a corresponding first trigger signal based on each of the first trigger points, and sending all the first trigger signals to a magnetic resonance device of the magnetic resonance image rearrangement system to trigger the magnetic resonance device to perform an image acquisition operation to obtain a plurality of initial images; Perform compensation calculation on the abnormal positive peak in the SCG signal based on the PPG signal and the individual model to obtain at least one second trigger point; A corresponding second trigger signal is generated based on all the first trigger points and all the second trigger points, and all the second trigger signals are sent to the magnetic resonance device to trigger the magnetic resonance device to perform a rearrangement operation on the multiple initial images to obtain a target image set.

2. The magnetic resonance image rearrangement method according to claim 1, characterized in that: The step of obtaining the facial PPG signal comprises: receiving a first image sequence transmitted by a first camera of the magnetic resonance image reordering system; Perform 0.5 Hz-4 Hz bandpass filtering on the G channel image sequence corresponding to the first image sequence to obtain a first waveform signal to be processed; Performing detrending processing on the first waveform signal to be processed to obtain a second waveform signal to be processed; Perform waveform normalization processing on the second waveform signal to be processed to obtain the PPG signal.

3. The magnetic resonance image rearrangement method according to claim 2, characterized in that: The step of acquiring the SCG signal of the heart while acquiring the PPG signal comprises: receiving a second image sequence transmitted by a second camera of the magnetic resonance image reordering system; Calculating the motion amplitude of each speckle image in the second image sequence in the X direction and the motion amplitude in the Y direction by using an optical flow method, cascading the motion amplitudes of all speckle images in the X direction into a motion amplitude sequence in the X direction, and cascading the motion amplitudes of all speckle images in the Y direction into a motion amplitude sequence in the Y direction; Calculating a motion angle based on the motion amplitude sequence in the X direction and the motion amplitude sequence in the Y direction; obtaining an initial signal based on the movement angle; The initial signal is preprocessed to obtain the SCG signal.

4. The magnetic resonance image rearrangement method according to claim 3, characterized in that: The step of preprocessing the initial signal to obtain the SCG signal comprises: removing the waveform trend of the initial signal to obtain a third waveform signal to be processed; The third waveform signal to be processed is subjected to waveform amplitude normalization processing to obtain the SCG signal.

5. The magnetic resonance image rearrangement method according to claim 1, characterized in that: The magnetic resonance image rearrangement method further comprises the step of constructing the individual model, wherein the step of constructing the individual model comprises: Set the first regression coefficient, the second regression coefficient, the third regression coefficient, the fourth regression coefficient and the error term; A third trigger point is set in each waveform period of the PPG signal; Obtain the heart rate, heart rate variability and heart beat interval of the target third trigger point; constructing the individual model based on the first regression coefficient, the second regression coefficient, the third regression coefficient, the fourth regression coefficient, the error term, the heart rate, the heart rate variability, and the heart beat interval; The target third trigger point is any third trigger point among all the third trigger points, and the individual model is used to output the time difference corresponding to the target third trigger point.

6. The magnetic resonance image rearrangement method according to claim 5, characterized in that: The step of performing compensation calculation on the abnormal positive peak in the SCG signal based on the PPG signal and the individual model to obtain at least one second trigger point comprises: Evaluate the PPG signal and the SCG signal to obtain an evaluation result; When the evaluation result is that the PPG signal meets the first preset condition, the SCG signal does not meet the second preset condition, and the individual model is in an available state, the following steps are performed: Using the individual model to estimate the time difference corresponding to the third trigger point of the target; The time difference and the time point corresponding to the target third trigger point are used to perform a difference calculation to obtain a first time point to be processed on the SCG signal that is in the same cycle time as the target third trigger point; A target time point is obtained based on the first time point to be processed and the SCG signal, and the target time point is used as the second trigger point.

7. The magnetic resonance image rearrangement method according to claim 6, characterized in that: The calculation formula for the step of performing difference calculation using the time difference and the time point corresponding to the target third trigger point to obtain the first to-be-processed time point on the SCG signal in the same cycle time as the target third trigger point is: ； in, is the first time point to be processed; The time point corresponding to the third trigger point of the target; is the time difference; is the index of the third trigger point of the target, i.e. A third trigger point.

8. A magnetic resonance image rearrangement system, characterized in that: include: A PPG signal acquisition module, used to acquire a PPG signal of the face, wherein the PPG signal is a photoplethysmographic signal; An SCG signal acquisition module, used to acquire an SCG signal of the heart while acquiring the PPG signal, wherein the SCG signal is a seismocardiography signal; A first trigger point acquisition module, used to take the time point corresponding to the positive peak value of each waveform period in the SCG signal as the first trigger point; A first trigger signal generating module, configured to generate a corresponding first trigger signal based on each of the first trigger points, and send all the first trigger signals to a magnetic resonance device of a magnetic resonance image rearrangement system to trigger the magnetic resonance device to perform an image acquisition operation to obtain a plurality of initial images; a compensation calculation module, configured to perform compensation calculation on the abnormal positive peak in the SCG signal based on the PPG signal and the individual model to obtain at least one second trigger point; A second trigger signal generating module is used to generate corresponding second trigger signals based on all the first trigger points and all the second trigger points, and send all the second trigger signals to the magnetic resonance device to trigger the magnetic resonance device to rearrange the multiple initial images to obtain a target image set.

9. A magnetic resonance image rearrangement system, characterized in that: include: A memory, a processor, a magnetic resonance device, a first camera, a second camera, a laser and a signal generator, wherein the memory is used to store a computer program, the processor is used to call and run the computer program stored in the memory to perform the steps of the magnetic resonance image rearrangement method according to any one of claims 1 to 7, the magnetic resonance device, the first camera and the second camera are all connected to the processor in communication, the first camera and the second camera are all connected to the signal generator in communication, and the laser is arranged on one side of the second camera; The signal generator is used to send a synchronization signal to the first camera and the second camera; The first camera is used to receive the synchronization signal, and start an image acquisition operation on the skin on the face based on the synchronization signal to obtain a first image sequence, and transmit the first image sequence to the processor; The second camera is used to receive the synchronization signal, and start an image acquisition operation on the heart part based on the synchronization signal to obtain a second image sequence, and transmit the second image sequence to the processor; When the second camera performs an image acquisition operation on the heart area, the laser emits laser light to irradiate the heart area.

10. A computer-readable storage medium, characterized in that: Used to store a computer program, wherein the computer program enables a computer to execute the steps of the magnetic resonance image rearrangement method according to any one of claims 1 to 7.

Images