Turnover angle measurement method, system and device, computer equipment and storage medium

Abstract

The invention relates to a flip angle measurement method, system and device, computer equipment and a storage medium. The method comprises the following steps: acquiring a first echo signal and a second echo signal; constructing a spin echo signal solving model according to the first echo signal; according to the second echo signal and the spin echo signal solving model, constructing a stimulated echo signal solving model; obtaining a target flip angle according to the spin echo signal solving model and the stimulated echo signal solving model; the target flipping angle is a flipping angle obtained by measuring a refocusing pulse flipping angle for performing magnetic resonance scanning on the region of interest. By adopting the method, the real flip angle of the refocusing pulse can be corrected, so that the imaging effect of the magnetic resonance image is improved.

Description

Technical Field

[0001] This application relates to the field of medical image technology, and in particular, to a flip angle measurement method, apparatus, computer device, storage medium, and computer program product. Background Art

[0002] With the development of computer technology, magnetic resonance imaging technology has emerged. This technology uses the principle of nuclear magnetic resonance (NMR), and based on the different attenuations of the released energy in different structural environments within a substance, by applying an external gradient magnetic field to detect the emitted electromagnetic waves, the position and type of the atomic nuclei constituting this object can be known, and based on this, an internal structure image of the object can be drawn.

[0003] Due to the problem that when using a magnetic resonance device, the transmitted voltage is inaccurate or the radiofrequency field is uneven, resulting in a deviation between the actual flip angle of the radiofrequency and the set value, which leads to poor imaging effects. In traditional technologies, a voltage calibration method is used to improve the deviation problem. However, the transmitted voltage calibration method uses a steam sequence for calibration, and it is difficult to adjust according to the change of the voltage during the calibration process, resulting in poor imaging effects of magnetic resonance images. Summary of the Invention

[0004] Based on this, it is necessary to provide a flip angle measurement method, system, apparatus, computer device, computer-readable storage medium, and computer program product that can improve the imaging effect of magnetic resonance images for the above technical problems.

[0005] In a first aspect, this application provides a flip angle measurement method. The method includes:

[0006] Obtain a first echo signal and a second echo signal;

[0007] According to the first echo signal, construct a spin echo signal solution model;

[0008] According to the second echo signal and the spin echo signal solution model, construct a stimulated echo signal solution model;

[0009] According to the spin echo signal solution model and the stimulated echo signal solution model, obtain a target flip angle; the target flip angle is the flip angle measured for the refocusing pulse flip angle of magnetic resonance scanning of the region of interest.

[0010] In a second aspect, this application also provides a magnetic resonance imaging system. The system includes: a magnetic resonance machine and a computer;

[0011] The magnetic resonance machine is used to perform magnetic resonance scanning on the region of interest;

[0012] The computer is used to obtain a first echo signal and a second echo signal;

[0013] The computer is further used to construct a spin echo signal solution model according to the first echo signal;

[0014] The computer is further used to construct a stimulated echo signal solution model according to the second echo signal and the constructed spin echo signal solution model;

[0015] The computer is also used to combine the spin echo signal solution model and the stimulated echo signal solution model to obtain a target flip angle; the target flip angle is the flip angle obtained by measuring the focusing pulse flip angle of the magnetic resonance scan of the region of interest.

[0016] In a third aspect, the present application also provides a flip angle measurement device. The device comprises:

[0017] An echo signal acquisition module, used for acquiring a first echo signal and a second echo signal;

[0018] A first model building module, used for building a spin echo signal solution model according to the first echo signal;

[0019] A second model building module, used for building a stimulated echo signal solution model according to the second echo signal and the built spin echo signal solution model;

[0020] The flip angle obtaining module is used to combine the spin echo signal solution model and the stimulated echo signal solution model to obtain a target flip angle; the target flip angle is the flip angle obtained by measuring the focusing pulse flip angle of the magnetic resonance scanning of the region of interest.

[0021] In a fourth aspect, the present application further provides a computer device. The computer device includes a memory and a processor, the memory stores a computer program, and the processor implements the following steps when executing the computer program:

[0022] Acquire a first echo signal and a second echo signal;

[0023] According to the first echo signal, construct a spin echo signal solution model;

[0024] Constructing a stimulated echo signal solution model according to the second echo signal and the spin echo signal solution model;

[0025] Based on the spin echo signal solving model and the stimulated echo signal solving model, a target flip angle is obtained; the target flip angle is the flip angle measured for the refocusing pulse flip angle of magnetic resonance scanning of the region of interest.

[0026] In a fifth aspect, the present application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program thereon, and when the computer program is executed by a processor, the following steps are implemented:

[0027] Obtain a first echo signal and a second echo signal;

[0028] Based on the first echo signal, construct a spin echo signal solving model;

[0029] Based on the second echo signal and the spin echo signal solving model, construct a stimulated echo signal solving model;

[0030] Based on the spin echo signal solving model and the stimulated echo signal solving model, obtain a target flip angle; the target flip angle is the flip angle measured for the refocusing pulse flip angle of magnetic resonance scanning of the region of interest.

[0031] In a sixth aspect, the present application also provides a computer program product. The computer program product includes a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0032] Obtain a first echo signal and a second echo signal;

[0033] Based on the first echo signal, construct a spin echo signal solving model;

[0034] Based on the second echo signal and the spin echo signal solving model, construct a stimulated echo signal solving model;

[0035] Based on the spin echo signal solving model and the stimulated echo signal solving model, obtain a target flip angle; the target flip angle is the flip angle measured for the refocusing pulse flip angle of magnetic resonance scanning of the region of interest.

[0036] For the above-mentioned flip angle measurement method, system, device, computer device, storage medium and computer program product, by obtaining a first echo signal and a second echo signal; based on the first echo signal, constructing a spin echo signal solving model; based on the second echo signal and the spin echo signal solving model, constructing a stimulated echo signal solving model; based on the spin echo signal solving model and the stimulated echo signal solving model, obtaining a target flip angle; the target flip angle is the flip angle measured for the refocusing pulse flip angle of magnetic resonance scanning of the region of interest.

[0037] By acquiring the first echo signal and the second echo signal at different excitation times, further constructing a spin echo signal solution model using the first echo signal; meanwhile, constructing a stimulated echo signal solution model using the second echo signal and the spin echo signal solution model. Finally, by integrating the spin echo signal solution model and the stimulated echo signal solution model, the target flip angle is calculated. It is possible to utilize the characteristics of the first two echoes of the fast spin echo sequence. When the flip angle of the refocusing pulse is not a pure 180°, the second echo signal will simultaneously have a spin echo signal (SE) and a stimulated echo signal (STE), and is actually stronger than the first echo signal. Through the difference between the two, the true flip angle of the refocusing pulse is corrected, thereby improving the imaging effect of the magnetic resonance image. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is an application environment diagram of a flip angle measurement method in an embodiment;

[0039] Figure 2 It is a schematic flowchart of a flip angle measurement method in an embodiment;

[0040] Figure 3 It is a schematic flowchart of a method for obtaining the relaxation change amount in an embodiment;

[0041] Figure 4 It is a schematic flowchart of a method for constructing a spin echo signal solution model in an embodiment;

[0042] Figure 5 It is a schematic flowchart of a method for constructing a stimulated echo signal solution model in an embodiment;

[0043] Figure 6 It is a schematic flowchart of a method for obtaining the target flip angle in an embodiment;

[0044] Figure 7 It is a schematic flowchart of a method for obtaining the target flip angle in another embodiment;

[0045] Figure 8 It is a schematic flowchart of a method for obtaining the initial echo signal in an embodiment;

[0046] Figure 9 It is a schematic flowchart of a method for obtaining the initial echo signal in another embodiment;

[0047] Figure 10 It is a schematic diagram of a fast spin echo sequence in an embodiment;

[0048] Figure 11 It is a structural block diagram of a flip angle measurement device in an embodiment;

[0049] Figure 12 The internal structure diagram of a computer device in an embodiment. Detailed implementation manners

[0050] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0051] A flip angle measurement method provided by an embodiment of the present application can be applied to an application environment as Figure 1 shown. Among them, the magnetic resonance machine 102 communicates with the server 104 through a network. The data storage system can store the data that the server 104 needs to process. The data storage system can be integrated on the server 104, or can be placed in the cloud or other network servers. The server 104 obtains a first echo signal and a second echo signal from the magnetic resonance machine 102; constructs a spin echo signal solution model according to the first echo signal; constructs a stimulated echo signal solution model according to the second echo signal and the spin echo signal solution model; obtains a target flip angle according to the spin echo signal solution model and the stimulated echo signal solution model; the target flip angle is the flip angle obtained by measuring the refocusing pulse flip angle for magnetic resonance scanning of the region of interest. Among them, the server 104 can be implemented by an independent server or a server cluster composed of multiple servers.

[0052] In one embodiment, as Figure 2 shown, a flip angle measurement method is provided. Taking the server in Figure 1 as an example for description, the method includes the following steps:

[0053] Step 202, obtain a first echo signal and a second echo signal.

[0054] Among them, the first echo signal can be the first echo signal in a fast spin echo sequence.

[0055] Among them, the second echo signal can be the second echo signal in a fast spin echo sequence, and the time interval between the first echo signal and the second echo signal is τ.

[0056] Specifically, when the magnetic resonance machine 102 scans the region of interest in the target object, the server 104 receives the fast spin echo sequence transmitted from the magnetic resonance machine 102, and measures the first echo signal and the second echo signal through the fast spin echo sequence, such as Figure 10 the first two echo signals S1 and S2 shown, where S2 includes a spin echo signal and a stimulated echo signal. For the fast spin echo sequence, each refocusing pulse angle is the same, that isFigure 10 as shown 。

[0057] Step 204: Construct a spin echo signal solution model based on the first echo signal.

[0058] Among them, the spin echo signal solution model can be a flip angle measurement model constructed based on the first echo signal. The spin echo signal solution model includes two parameters: the first echo signal and the flip angle.

[0059] Specifically, for the first echo signal, since there is only a spin echo signal (SE signal), a spin echo signal solution model is constructed using the first echo signal, and its mathematical expression is as follows:

[0060]

[0061] where is the initial signal after excitation, is the first echo signal, , ,then , is the true flip angle to be solved, is the longitudinal relaxation time of hydrogen protons.

[0062] Step 206: Construct a stimulated echo signal solution model based on the second echo signal and the spin echo signal solution model.

[0063] Among them, the stimulated echo signal solution model can be a flip angle measurement model constructed based on the second echo signal. The spin echo signal solution model includes two parameters: the second echo signal and the flip angle.

[0064] Specifically, for the second echo signal, since it includes a spin echo signal (SE signal) and a stimulated echo signal (STE), a spin echo signal solution model is constructed using the second echo signal, and its mathematical expression is as follows:

[0065]

[0066] where is the initial signal after excitation, is the second echo signal, , , ,then , is the true flip angle to be solved, is the longitudinal relaxation time of hydrogen protons, is the transverse relaxation time of hydrogen protons, is to time interval.

[0067] Step 208, obtaining a target flip angle according to a spin echo signal solution model and a stimulated echo signal solution model.

[0068] The target flip angle may be a flip angle obtained by measuring a focusing pulse flip angle of a magnetic resonance scan performed on the region of interest.

[0069] Specifically, the spin echo signal solution model and the stimulated echo signal solution model are solved together to obtain the initial signal after excitation and the solved real flip angle, and the mathematical expression is as follows:

[0070]

[0071] The solution is:

[0072]

[0073] in,

[0074] therefore,

[0075]

[0076] In the above-mentioned flip angle measurement method, a first echo signal and a second echo signal are obtained; a spin echo signal solution model is constructed according to the first echo signal; a stimulated echo signal solution model is constructed according to the second echo signal and the spin echo signal solution model; a target flip angle is obtained according to the spin echo signal solution model and the stimulated echo signal solution model; the target flip angle is the flip angle obtained by measuring the focusing pulse flip angle of the magnetic resonance scanning of the region of interest.

[0077] By acquiring the first echo signal and the second echo signal at different excitation times. The first echo signal is further used to construct a spin echo signal solution model; at the same time, the second echo signal and the spin echo signal solution model are used to construct a stimulated echo signal solution model. Finally, the spin echo signal solution model and the stimulated echo signal solution model are combined to calculate the target flip angle. The characteristics of the first two echoes of the fast spin echo sequence can be used. When the flip angle of the focusing pulse is not pure 180°, the second echo signal will have both a spin echo signal (SE) and a stimulated echo signal (STE), which is stronger than the first echo signal. Through the difference between the two, the real flip angle of the focusing pulse is corrected, thereby improving the imaging effect of the magnetic resonance image.

[0078] In one embodiment, Figure 3 As shown, before the step of constructing a spin echo signal solution model according to the first echo signal, the method further includes:

[0079] Step 302: Determine the transverse relaxation time and the longitudinal-transverse relaxation time.

[0080] Among them, the longitudinal relaxation time can be the longitudinal relaxation time of hydrogen protons, that is, the spin-lattice relaxation time, which reflects the time required for the spin nucleus to transfer the absorbed energy to the surrounding lattice. It is also the time required for the protons to return from the longitudinal magnetization to the transverse magnetization after a 90° radiofrequency pulse and then back to the state before the longitudinal magnetization excitation. It is called .

[0081] Among them, the transverse relaxation time can be the transverse relaxation time of hydrogen protons, that is, the spin-spin relaxation time, also known as the transverse relaxation time, which reflects the process of transverse magnetization decay and loss. It is also the time that the transverse magnetization maintains, and it is called . The decay is caused by the mutual magnetization between resonant protons and is different from it causes a change in phase.

[0082] Specifically, determine the transverse relaxation time corresponding to the first echo signal, that is, determine the time required for the first echo signal to return from the excited state to the reference state in the horizontal direction. And determine the transverse relaxation time corresponding to the second echo signal, that is, determine the time required for the second echo signal to return from the excited state to the reference state in the horizontal direction, and determine the longitudinal relaxation time corresponding to the second echo signal, that is, determine the time required for the second echo signal to return from the excited state to the reference state in the vertical direction.

[0083] Step 304: Obtain the first relaxation change amount according to the transverse relaxation time and the echo sequence time interval.

[0084] Among them, the first relaxation change amount can be the relaxation change amount of the first echo signal.

[0085] Specifically, determine the transverse relaxation time of the physical system through experiments or measurements, that is, the time required for the signal to return from the transverse excited state to the reference state. Combine the echo sequence time interval, that is, observe the time difference between adjacent echo sequences. Through the analysis of these two parameters, the first relaxation change amount can be calculated, which represents the degree of change of the system in the transverse direction and is a measure of the transverse relaxation. The calculation expression of the first relaxation change amount is:

[0086] Step 306: Obtain the second relaxation change amount according to the longitudinal relaxation time and the echo sequence time interval.

[0087] Among them, the second relaxation variation can be the relaxation variation of the second echo signal.

[0088] Specifically, first, it is necessary to determine the longitudinal relaxation time, that is, the time required for the system to return from the longitudinal excitation state to the reference state, and this recovery time is obtained through experiments or measurements. Next, in combination with the echo sequence time interval, that is, observing the time difference between adjacent echo sequences. By analyzing these two parameters, the second relaxation variation can be calculated, which represents the degree of change of the system in the longitudinal direction. Specifically, this variation reflects the nature of longitudinal relaxation, that is, the change in the speed and amplitude of the system returning from the excitation state to the reference state in the vertical direction. Among them, the calculation expression of the second relaxation variation is: 。

[0089] In this embodiment, by calculating the transverse relaxation time and the echo sequence time interval, the first relaxation variation is obtained, which can quantify the degree of change of the sample in the transverse direction. Similarly, by calculating the longitudinal relaxation time and the echo sequence time interval, the second relaxation variation is obtained, which can understand the degree of change of the sample in the vertical direction. Such relaxation variations can be used in magnetic resonance imaging to improve the discrimination of different tissue structures and properties, enhance the image contrast, and thus enhance the resolution of the internal characteristics of the sample in medicine and science. This is of substantial help in fields such as disease diagnosis, research on biological tissue structures, and materials science.

[0090] In one embodiment, as Figure 4 shown, according to the first echo signal, a spin echo signal solution model is constructed, including:

[0091] Step 402, taking the sine value of the target flip angle to be solved as the intermediate parameter for solving the echo signal.

[0092] Among them, the intermediate parameter for solving the echo signal can be the intermediate quantity used to solve the target flip angle, and performing trigonometric function substitution is beneficial to simplifying the solution process and the solution quantity.

[0093] Specifically, first, it is necessary to determine the target flip angle to be solved, and then take the general sine value of the target flip angle to be solved as the intermediate parameter for solving the echo signal. This involves substituting the value of the target flip angle to be solved into the sine function to calculate its sine value. The obtained sine value can serve as an important intermediate parameter in the solution of the echo signal, helping to analyze and understand the characteristics of the echo signal. Specifically, the sine value may be used to adjust the phase or amplitude of the signal in order to more accurately interpret or simulate the echo response of the target to be solved. Among them, the mathematical expression of the intermediate parameter for solving the echo signal is as follows: 。

[0094] Step 404: Solve for the intermediate parameter, the first relaxation variation, and the first echo signal based on the echo signal, and construct a spin echo signal solution model.

[0095] Specifically, use the sine value of the target flip angle to be solved as the intermediate parameter for solving the echo signal, which is a key parameter for constructing the spin echo signal solution model. Combine the first relaxation variation, which reflects the degree of change in the system in the transverse direction, and integrate the first echo signal, i.e., the initial echo signal. Use these parameters and information to construct the spin echo signal solution model. This model can be a mathematical model or algorithm used to describe and explain the relationship between the echo signal and the target, especially in the spin system. The mathematical expression of the spin echo signal solution model is as follows:

[0096] In this embodiment, by using the sine value of the target flip angle as the intermediate parameter for solving the echo signal, the properties of the signal can be described more accurately. The intermediate parameter for solving the echo signal can be used to adjust the phase or amplitude of the signal, thereby constructing the spin echo signal solution model more precisely. The construction of the spin echo signal solution model can provide more detailed information about the target to be solved, making the magnetic resonance imaging more accurate and clear. This has substantial benefits for medical diagnosis, scientific research, and precise imaging in other fields.

[0097] In one embodiment, as Figure 5 shown, construct a stimulated echo signal solution model based on the second echo signal and the spin echo signal solution model, including:

[0098] Step 502: Solve for the intermediate parameter, the first relaxation variation, the second relaxation variation, and the second echo signal based on the echo signal, and construct an intermediate echo signal solution model.

[0099] Among them, the intermediate echo signal solution model can be an intermediate stimulated echo signal model that takes into account the spin echo signal (SE) and the stimulated echo signal (STE) during the modeling process.

[0100] Specifically, use the intermediate parameter for solving the echo signal that includes information such as the sine value of the flip angle as the key input for constructing the intermediate echo signal solution model. Integrate the first relaxation variation and the second relaxation variation, which respectively represent the relaxation times of hydrogen protons in the transverse and longitudinal directions. Combine and consider the second echo signal, i.e., the echo signal after the hydrogen protons have undergone transverse and longitudinal relaxation. Combine these parameters and information to construct the intermediate echo signal solution model, which is used to describe and explain a more comprehensive relationship between the echo signal and the target, especially in a magnetic resonance machine.

[0101] Step 504: Linearly fit the spin echo signal solving model and the intermediate echo signal solving model to construct a stimulated echo signal solving model.

[0102] Specifically, linearly fitting the spin echo signal solving model and the intermediate echo signal solving model may involve adjusting the parameters of the models to make the results predicted by the models as consistent as possible with the actually observed echo signals. Once the linear fitting is completed, a more comprehensive stimulated echo signal solving model will be obtained, which comprehensively considers the information of the spin echo signal (SE) and the stimulated echo signal (STE). Its mathematical expression is:

[0103] In this embodiment, by linearly fitting after combining the intermediate echo signal solving model and the spin echo signal solving model to form a stimulated echo signal solving model, it helps to more comprehensively and accurately capture the dynamic characteristics of the signal. This improves the accuracy of imaging and the resolution ability of the internal structure of biological tissues, providing a more powerful tool for medical and scientific research.

[0104] In one embodiment, as Figure 6 shown, according to the spin echo signal solving model and the stimulated echo signal solving model, the target flip angle is obtained, including:

[0105] Step 602: Substitute the spin echo signal solving model into the stimulated echo signal solving model to obtain a substituted echo signal solving model.

[0106] Specifically, since the simultaneous equations of the spin echo signal solving model and the stimulated echo signal solving model are as follows:

[0107]

[0108] Transpose the first expression of the equations to get . Further substitute the transposed expression into the second expression of the equations to obtain the substituted echo signal solving model

[0109] Step 604: Solve the intermediate parameter of the echo signal solving in the substituted echo signal solving model to obtain the solved intermediate parameter of the echo signal solving.

[0110] Specifically, solve the intermediate parameter of the echo signal solving in the substituted echo signal solving model to obtain the solved intermediate parameter of the echo signal solving.

[0111] Step 606: Calculate the arcsine value of the solved intermediate parameter of the echo signal solving to obtain the target flip angle.

[0112] Specifically, since the expression of the intermediate parameter of the echo signal is ,and It has been obtained in step 604, so the target flip angle can be obtained by calculating the inverse trigonometric function. .

[0113] In this embodiment, by substituting the spin echo signal solution model into the stimulated echo signal solution model to form an echo signal solution model, the system response can be simulated more accurately. By solving the echo signal solution intermediate parameters in the substitution model, a more accurate description of the system dynamic characteristics is obtained. Finally, the arc sine value of the echo signal solution intermediate parameter is calculated to obtain the target flip angle, thereby improving the imaging accuracy of magnetic resonance imaging and enhancing the analysis capability of the internal structure and properties of the sample.

[0114] In one embodiment, Figure 7 As shown, the spin echo signal solution model and the stimulated echo signal solution model are combined to obtain the target flip angle, including:

[0115] Step 702 : Add the model parameters of the spin echo signal solution model and the model parameters of the stimulated echo signal solution model to obtain the added echo signal solution model.

[0116] The model solved by adding the echo signal may be a new model obtained by adding the model parameters of the model solved by the spin echo signal and the model parameters of the model solved by the stimulated echo signal.

[0117] Specifically, the simultaneous equations of the spin echo signal solution model and the stimulated echo signal solution model are as follows:

[0118]

[0119] Add the first equation of the above equation group to the second equation to obtain a new equation. The new equation is the solution model of the added echo signal. The mathematical expression is: .

[0120] Step 704, solving the echo signal solution intermediate parameters in the added echo signal solution model to obtain the echo signal solution intermediate parameters.

[0121] Specifically, the echo signal is substituted into the model to solve Solve the intermediate parameters of the echo signal in The solution is performed to obtain the intermediate parameters of the echo signal solution.

[0122] Step 706, calculating the arc sine value of the intermediate parameter of the echo signal to obtain the target flip angle.

[0123] Specifically, since the expression of the intermediate parameter of the echo signal is , and has been obtained through step 704. Therefore, through the calculation of the inverse trigonometric function, the target flip angle can be obtained.

[0124] In this embodiment, by adding the model parameters of the spin echo signal solution model and the stimulated echo signal solution model to form an added echo signal solution model, a more comprehensive modeling of the system response is achieved. Subsequently, by solving the intermediate parameters of the echo signal solution in the added model, a more accurate description of the system dynamic characteristics is obtained. Finally, by calculating the arcsine value of the intermediate parameter of the echo signal solution, the target flip angle is obtained. This process obtains more accurate target information through more comprehensive model consideration, which is beneficial to improving the accuracy of magnetic resonance imaging.

[0125] In one embodiment, as Figure 8 shown, the method further includes:

[0126] Step 802, substituting the spin echo signal solution model into the stimulated echo signal solution model to obtain a substituted echo signal solution model.

[0127] Specifically, since the simultaneous equations of the spin echo signal solution model and the stimulated echo signal solution model are as follows:

[0128]

[0129] By moving the first expression of the equation set, we get . Further substituting the moved expression into the second expression of the equation set, we obtain the substituted echo signal solution model

[0130] Step 804, solving the initial echo signal in the substituted echo signal solution model.

[0131] Wherein, the initial echo signal is the first echo signal in the fast spin echo sequence.

[0132] Specifically, solving in the substituted echo signal solution model to obtain the initial echo signal.

[0133] In this embodiment, by substituting the spin echo signal solution model into the stimulated echo signal solution model, a substituted echo signal solution model is obtained, which helps to more accurately simulate and understand the dynamic response of the system. Subsequently, by solving the initial echo signal in the substituted model, a detailed understanding of the initial state of the system can be obtained. It is helpful for fields such as magnetic resonance imaging to enhance the analysis of the internal structure and properties of the sample and improve the accuracy and reliability of imaging.

[0134] In one embodiment, as Figure 9 shown, the method further includes:

[0135] Step 902: Add the model parameters of the spin echo signal solution model and the model parameters of the stimulated echo signal solution model to obtain an added echo signal solution model.

[0136] Since the simultaneous equations of the spin echo signal solution model and the stimulated echo signal solution model are as follows:

[0137]

[0138] Adding the first equation and the second equation of the above system of equations to obtain a new equation, and the new equation is the added echo signal solution model, and the mathematical expression is: .

[0139] Step 904: Solve the initial echo signal in the added echo signal solution model.

[0140] Specifically, solve substituted into the echo signal solution model to obtain the initial echo signal.

[0141] In this embodiment, by adding the model parameters of the spin echo signal solution model and the model parameters of the stimulated echo signal solution model to form an added echo signal solution model, it helps to more comprehensively consider all aspects of the system dynamic response. Further, by solving the initial echo signal in the added model, more detailed initial state information can be obtained, which is beneficial to improving the analysis of the internal structure and properties of the sample. This process is beneficial in fields such as magnetic resonance imaging, can enhance the accuracy and reliability of imaging, and provide a more powerful tool for scientific research and medical diagnosis.

[0142] It should be understood that although the steps in the flowcharts involved in the above embodiments are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same moment, but can be executed at different moments, and the execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0143] Based on the same inventive concept, the embodiment of the present application also provides a flip angle measuring device for implementing the flip angle measuring method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more flip angle measuring device embodiments provided below can refer to the limitations of a flip angle measuring method above, and will not be repeated here.

[0144] In one embodiment, Figure 11 As shown, a flip angle measuring device is provided, comprising: an echo signal acquisition module 1102, a first model construction module 1104, a second model construction module 1106 and a flip angle obtaining module 1108, wherein:

[0145] An echo signal acquisition module 1102 is used to acquire a first echo signal and a second echo signal;

[0146] A first model building module 1104 is used to build a spin echo signal solution model according to the first echo signal;

[0147] A second model building module 1106, configured to build a stimulated echo signal solution model according to the second echo signal and the spin echo signal solution model;

[0148] The flip angle obtaining module 1108 is used to jointly solve the spin echo signal solution model and the stimulated echo signal solution model to obtain a target flip angle; the target flip angle is the flip angle obtained by measuring the focusing pulse flip angle of the magnetic resonance scan of the region of interest.

[0149] In one embodiment, the first model building module 1104 is also used to determine the transverse relaxation time and the longitudinal transverse relaxation time; obtain the first relaxation change according to the transverse relaxation time and the echo sequence time interval; and obtain the second relaxation change according to the longitudinal relaxation time and the echo sequence time interval.

[0150] In one embodiment, the first model building module 1104 is further used to use the sine value of the target flip angle to be solved as an intermediate parameter for solving the echo signal; and to build a spin echo signal solution model according to the intermediate parameter for solving the echo signal, the first relaxation change and the first echo signal.

[0151] In one embodiment, the second model construction module 1106 is also used to solve the intermediate parameters, the first relaxation change, the second relaxation change and the second echo signal according to the echo signal to construct an intermediate echo signal solution model; linearly fit the spin echo signal solution model and the intermediate echo signal solution model to construct a stimulated echo signal solution model.

[0152] In one embodiment, the flip angle obtaining module 1108 is further configured to substitute the spin echo signal solving model into the stimulated echo signal solving model to obtain a substituted echo signal solving model; solve the intermediate echo signal solving parameters in the substituted echo signal solving model to obtain the solved intermediate echo signal solving parameters; calculate the arcsine value of the solved intermediate echo signal solving parameters to obtain the target flip angle.

[0153] In one embodiment, the flip angle obtaining module 1108 is further configured to add the model parameters of the spin echo signal solving model and the model parameters of the stimulated echo signal solving model to obtain an added echo signal solving model; solve the intermediate echo signal solving parameters in the added echo signal solving model to obtain the solved intermediate echo signal solving parameters; calculate the arcsine value of the solved intermediate echo signal solving parameters to obtain the target flip angle.

[0154] In one embodiment, the flip angle obtaining module 1108 is further configured to substitute the spin echo signal solving model into the stimulated echo signal solving model to obtain a substituted echo signal solving model; solve the initial echo signal in the substituted echo signal solving model.

[0155] In one embodiment, the flip angle obtaining module 1108 is further configured to add the model parameters of the spin echo signal solving model and the model parameters of the stimulated echo signal solving model to obtain an added echo signal solving model; solve the initial echo signal in the added echo signal solving model.

[0156] Each module in the above flip angle measuring device can be implemented in whole or in part by software, hardware, and their combination. The above modules can be embedded in the processor of the computer device in hardware form or be independent of it, or can be stored in the memory of the computer device in software form, so that the processor can call and execute the operations corresponding to the above respective modules.

[0157] In one embodiment, a magnetic resonance imaging system is provided, and the system includes: a magnetic resonance scanning device and a computer;

[0158] A magnetic resonance machine for performing magnetic resonance scanning on a region of interest;

[0159] A computer for acquiring a first echo signal and a second echo signal;

[0160] The computer is further configured to construct a spin echo signal solving model according to the first echo signal;

[0161] The computer is further configured to construct a stimulated echo signal solving model according to the second echo signal and the constructed spin echo signal solving model;

[0162] The computer is also used to jointly solve the spin echo signal model and the stimulated echo signal model to obtain a target flip angle; the target flip angle is the flip angle obtained by measuring the focusing pulse flip angle of the magnetic resonance scan of the region of interest.

[0163] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 12 As shown. The computer device includes a processor, a memory and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store server data. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a flip angle measurement method is implemented.

[0164] Those skilled in the art will understand that Figure 12 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0165] In one embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above method embodiments when executing the computer program.

[0166] In one embodiment, a computer-readable storage medium is provided, storing a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0167] In one embodiment, a computer program product or computer program is provided, the computer program product or computer program includes computer instructions, the computer instructions are stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device performs the steps in the above-mentioned method embodiments.

[0168] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0169] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. 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 methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0170] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, 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, it should be considered as the scope described in this specification.

[0171] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for measuring the flipping angle, characterized in that The method comprises: Acquire a first echo signal and a second echo signal; According to the first echo signal, construct a spin echo signal solution model; Constructing a stimulated echo signal solution model according to the second echo signal and the spin echo signal solution model; A target flip angle is obtained according to the spin echo signal solution model and the stimulated echo signal solution model; the target flip angle is a flip angle obtained by measuring a focusing pulse flip angle of a magnetic resonance scan of the region of interest.

2. The method according to claim 1, wherein Before the step of constructing a spin echo signal solution model according to the first echo signal, the method further includes: Determine transverse relaxation time and longitudinal and transverse relaxation time; Obtaining a first relaxation variation according to the transverse relaxation time and the echo sequence time interval; A second relaxation variation is obtained according to the longitudinal relaxation time and the echo sequence time interval.

3. The method according to claim 2, wherein The step of constructing a spin echo signal solution model according to the first echo signal includes: The sine value of the target flip angle to be solved is used as an intermediate parameter of the echo signal; The spin echo signal solution model is constructed according to the intermediate parameters solved by the echo signal, the first relaxation change amount and the first echo signal.

4. The method according to claim 3, characterized in that, The step of constructing a stimulated echo signal solution model according to the second echo signal and the spin echo signal solution model includes: Solving the intermediate parameters, the first relaxation change amount, the second relaxation change amount and the second echo signal according to the echo signal, and constructing an intermediate echo signal solution model; The spin echo signal solution model and the intermediate echo signal solution model are linearly fitted to construct the stimulated echo signal solution model.

5. The method according to any one of claims 3 to 4, characterized in that, The step of obtaining a target flip angle according to the spin echo signal solution model and the stimulated echo signal solution model comprises: Substituting the spin echo signal solution model into the stimulated echo signal solution model to obtain a substituted echo signal solution model; Solving the echo signal solving intermediate parameters substituted into the echo signal solving model to obtain solving the echo signal solving intermediate parameters; The arc sine value of the intermediate parameter of the echo signal is calculated to obtain the target flip angle.

6. The method according to any one of claims 3 to 4, characterized in that The method of combining the spin echo signal solution model and the stimulated echo signal solution model to obtain a target flip angle includes: Adding the model parameters of the spin echo signal solution model and the model parameters of the stimulated echo signal solution model to obtain an added echo signal solution model; Solving the echo signal solving intermediate parameters in the added echo signal solving model to obtain solving the echo signal solving intermediate parameters; The arc sine value of the intermediate parameter of the echo signal is calculated to obtain the target flip angle.

7. The method according to any one of claims 3 to 4, characterized in that The method further comprises: Substituting the spin echo signal solution model into the stimulated echo signal solution model to obtain a substituted echo signal solution model; Solve the initial echo signal substituted into the echo signal solution model.

8. The method according to any one of claims 3 to 4, characterized in that The method further comprises: Adding the model parameters of the spin echo signal solution model and the model parameters of the stimulated echo signal solution model to obtain an added echo signal solution model; Solving the added echo signal solves the initial echo signal in the model.

9. A magnetic resonance imaging system, characterized in that, The system comprises: a magnetic resonance scanning device and a computer; The magnetic resonance machine is used to perform magnetic resonance scanning on a region of interest; The computer is used to obtain a first echo signal and a second echo signal; The computer is further used to construct a spin echo signal solution model according to the first echo signal; The computer is further used to construct a stimulated echo signal solution model according to the second echo signal and the constructed spin echo signal solution model; The computer is also used to combine the spin echo signal solution model and the stimulated echo signal solution model to obtain a target flip angle; the target flip angle is the flip angle obtained by measuring the focusing pulse flip angle of the magnetic resonance scan of the region of interest.

10. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

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