Relaxation time determination method and device and magnetic resonance quantitative imaging method

Abstract

The invention relates to a relaxation time determination method and device and a magnetic resonance quantitative imaging method. The method comprises the steps that preset echo time is acquired to generate a magnetic resonance image, the magnetic resonance image comprises a plurality of pixel points, and each pixel point has a corresponding pixel signal; acquiring a plurality of candidate relaxation times, and performing image simulation processing by using the plurality of candidate relaxation times and a preset echo time to obtain simulation pixel signals which are respectively corresponding to the candidate relaxation times and are matched with the intensity of the target emission field; the target emission field intensity is the emission field intensity of the position where the pixel point is located; and determining the difference degree between each simulation pixel signal and the pixel signal, and taking the candidate relaxation time corresponding to the simulation pixel signal with the minimum difference degree as the target relaxation time of the pixel point. By adopting the method, the accuracy of the relaxation time can be improved.

Description

Technical Field

[0001] The present application relates to the field of magnetic resonance technology, and in particular to a relaxation time determination method and device, and a magnetic resonance quantitative imaging method. Background Art

[0002] In the field of magnetic resonance technology, magnetic resonance signals can be collected by using multiple magnetic resonance pulse sequences with different echo times, and multiple magnetic resonance images can be reconstructed based on the magnetic resonance signals corresponding to the multiple different echo times, and the relaxation time of the magnetic resonance imaging tissue can be calculated through the multiple magnetic resonance images.

[0003] In the prior art, a pulse sequence with multiple echo times is conventionally used to collect magnetic resonance data. After collecting magnetic resonance signals at multiple echo times and reconstructing multiple magnetic resonance images, the signal value of the tissue at position r in the i-th magnetic resonance image is M TEi , the relaxation time of the tissue at position r can be obtained by fitting the obtained i signal values ​​with the known i echo times. The three-parameter model used for fitting is: Among them, M 0 is the initial transverse magnetization vector, and C is the initial image deviation value caused by noise.

[0004] In a high field strength magnetic resonance system, for example, one with a field strength greater than or equal to 3 Tesla, the actual radio frequency magnetic fields at different physical locations vary greatly, causing the magnetic resonance signals at different locations to be modulated differently. Existing methods that rely on fitting solutions to obtain relaxation times are not very accurate. Summary of the invention

[0005] Based on this, it is necessary to provide a relaxation time determination method, device and magnetic resonance quantitative imaging method that can improve the accuracy of relaxation time in response to the above technical problems.

[0006] In a first aspect, the present application provides a method for determining a relaxation time, the method comprising:

[0007] Acquiring a preset echo time to generate a magnetic resonance image, pixels of the magnetic resonance image, each pixel having a corresponding pixel signal;

[0008] Acquire multiple candidate relaxation times, and use the multiple candidate relaxation times and the preset echo time to perform image simulation processing to obtain simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity; the target emission field intensity is the emission field intensity at the location of the pixel point;

[0009] The degree of difference between each simulated pixel signal and the pixel signal is determined, and the candidate relaxation time corresponding to the simulated pixel signal with the smallest degree of difference is used as the target relaxation time of the pixel point.

[0010] In one embodiment, image simulation processing is performed using multiple candidate relaxation times and a preset echo time to obtain simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity, including:

[0011] Acquire multiple radio frequency pulse flip angles;

[0012] Performing image simulation processing using multiple candidate relaxation times, multiple radio frequency pulse flip angles, and a preset echo time to obtain a simulation result data set; the simulation result data set includes multiple simulation pixel signals corresponding to different emission field intensities;

[0013] From the simulation result data set, a simulation pixel signal corresponding to each candidate relaxation time and matching the target emission field intensity is obtained; the target emission field intensity corresponds to any one of a plurality of radio frequency pulse flip angles.

[0014] In one embodiment, obtaining simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity from the simulation result data set includes:

[0015] Taking the target emission field intensity as an index value, a plurality of simulation pixel signals matching the target emission field intensity are obtained from the simulation result data set;

[0016] A plurality of simulated pixel signals matching the target emission field intensity are used as simulated pixel signals corresponding to the candidate relaxation times.

[0017] In one embodiment, the number of echo times is multiple;

[0018] Obtaining a magnetic resonance image corresponding to a preset echo time includes:

[0019] Based on the multiple echo times, a magnetic resonance image corresponding to each echo time is generated; pixel signals corresponding to each pixel point in the multiple magnetic resonance images respectively form a pixel signal set;

[0020] Using multiple candidate relaxation times and preset echo times to perform image simulation processing, a simulated pixel signal corresponding to each candidate relaxation time and matching the target emission field intensity is obtained, including:

[0021] Using multiple candidate relaxation times and multiple echo times to perform image simulation processing, a set of simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity is obtained; each simulated pixel signal set includes multiple simulated pixel signals, each simulated pixel signal is obtained by performing image simulation processing at different echo times;

[0022] Determine the degree of difference between each simulated pixel signal and the pixel signal, and use the candidate relaxation time corresponding to the simulated pixel signal with the smallest degree of difference as the target relaxation time of the pixel point, including:

[0023] The degree of difference between each simulated pixel signal set and the pixel signal set is determined, and the candidate relaxation time corresponding to the simulated pixel signal set with the smallest degree of difference is used as the target relaxation time of the pixel point.

[0024] In one embodiment, determining the degree of difference between each set of simulated pixel signals and the set of pixel signals includes:

[0025] Obtaining a current simulation pixel signal set and a set distance from a pixel signal set; the current simulation pixel signal set is any simulation pixel signal set;

[0026] The set distance is taken as the difference between the current simulation pixel signal set and the pixel signal set.

[0027] In one embodiment, image simulation processing is performed using multiple candidate relaxation times and a preset echo time to obtain simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity, including:

[0028] Get the target emission field intensity corresponding to the pixel point;

[0029] Image simulation processing is performed using multiple candidate relaxation times, target emission field intensities, and preset echo times to obtain simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity.

[0030] In one embodiment, obtaining the target emission field intensity corresponding to the pixel point includes:

[0031] Using a pre-scan sequence, pre-scanning a magnetic resonance device associated with the magnetic resonance image is performed to obtain a transmission field distribution image;

[0032] Obtain pixel data of pixels in the emission field distribution image;

[0033] The pixel data is used as the target emission field intensity.

[0034] In one embodiment, the target relaxation time is the transverse relaxation time.

[0035] In a second aspect, the present application provides a magnetic resonance quantitative imaging method, the method comprising:

[0036] Acquire a plurality of magnetic resonance images corresponding to the echo times, the magnetic resonance image comprising a plurality of pixel points, each pixel point having a corresponding pixel signal;

[0037] Acquire multiple candidate relaxation times, and use the multiple candidate relaxation times and echo times to perform simulation processing to obtain simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity; the target emission field intensity is the emission field intensity at the location of the pixel point;

[0038] Performing a traversal operation on the simulated pixel signal to determine a simulated pixel signal matching the pixel signal, and determining a target relaxation time of the pixel point according to the simulated pixel signal matching the pixel signal; and,

[0039] Displays the reference echo signal plot corresponding to the target relaxation time.

[0040] In a third aspect, the present application further provides a relaxation time determination device, the device comprising:

[0041] A pixel signal determination module, used to obtain a preset echo time to generate a magnetic resonance image, the magnetic resonance image includes a plurality of pixel points, each pixel point has a corresponding pixel signal;

[0042] A simulation signal determination module is used to obtain multiple candidate relaxation times, and use the multiple candidate relaxation times and the preset echo time to perform image simulation processing to obtain a simulation pixel signal corresponding to each candidate relaxation time and matching the target emission field intensity; the target emission field intensity is the emission field intensity at the location of the pixel point;

[0043] The relaxation time determination module is used to determine the difference between each simulated pixel signal and the pixel signal, and to use the candidate relaxation time corresponding to the simulated pixel signal with the smallest difference as the target relaxation time of the pixel point.

[0044] The relaxation time determination method, device and magnetic resonance quantitative imaging method described above obtain a preset echo time to generate a magnetic resonance image, and each pixel of the magnetic resonance image has a corresponding pixel signal; obtain multiple candidate relaxation times, and use multiple candidate relaxation times and preset echo times to perform image simulation processing to obtain simulated pixel signals that correspond to each candidate relaxation time and match the target emission field intensity; the target emission field intensity is the emission field intensity at the location of the pixel point; determine the degree of difference between each simulated pixel signal and the pixel signal, and use the candidate relaxation time corresponding to the simulated pixel signal with the smallest degree of difference as the target relaxation time of the pixel point. Compared with traditional technologies, the present application can perform image simulation through multiple candidate relaxation times and preset echo times to obtain simulated pixel signals corresponding to the target emission field intensity at the location of the pixel point, and further obtain pixel signals corresponding to the magnetic resonance image reconstructed and generated by the preset echo time, and by determining the degree of difference between the simulated pixel signal and the pixel signal, the candidate relaxation time corresponding to the simulated pixel signal with the smallest degree of difference can be determined as the target relaxation time. Thus, by the above method, the target relaxation time is obtained from a wide range of candidate relaxation times that may exist, and the influence of the radio frequency magnetic field inhomogeneity on the accuracy of calculating the local relaxation time in the magnetic resonance image is reduced, thereby improving the accuracy of the relaxation time. By determining the relaxation time by the relaxation time determination method provided by the present application, and using the relaxation time for magnetic resonance imaging, the accuracy of the magnetic resonance image obtained by magnetic resonance imaging can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A schematic flow chart of a relaxation time determination method in one embodiment;

[0046] Figure 2 A schematic diagram of a flow chart of a step of obtaining a simulated pixel signal in an embodiment;

[0047] Figure 3 A schematic diagram of a flow chart of a step of obtaining a simulated pixel signal from a simulation result data set in one embodiment;

[0048] Figure 4 A schematic diagram of a flow chart of a step of obtaining multiple transmission field intensities in one embodiment;

[0049] Figure 5 A schematic flow chart of a relaxation time determination method in another embodiment;

[0050] Figure 6 is a structural block diagram of a relaxation time determination device in one embodiment;

[0051] Figure 7 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with 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.

[0053] In magnetic resonance scanning, the RF transmitting coil transmits a RF signal tuned to the Larmor frequency to generate a RF magnetic field, which causes the precession spin of the atomic nucleus to deviate from the longitudinal direction and the magnetization vector to deviate from the main magnetic field direction, resulting in an amplitude of M 0 The transverse magnetization vector. The magnetic resonance signal, i.e. the transverse magnetization vector, decays over time, and the expression for this decay is:

[0054] M xy (TR,TE)=M 0 (1-e -TR / T1 ) -TE / T2 (1)

[0055] Among them, M xy is the transverse magnetization vector, M xy The amplitude is the magnetic resonance signal intensity, TR is the repetition interval of the radio frequency pulse, TE is the time of receiving the magnetic resonance echo, T1 and T2 are the longitudinal relaxation time and transverse relaxation time of the tissue generating the signal. When TR is much larger than the T1 of the tissue, the difference in T1 can be ignored, and equation (1) can be simplified to:

[0056]

[0057] In this way, multiple magnetic resonance images can be reconstructed by using magnetic resonance signals acquired by using multiple magnetic resonance pulse sequences with different TEs, and the T2 value of the imaging tissue can be calculated from these magnetic resonance images.

[0058] In the prior art, a multi-TE pulse sequence is conventionally used for data acquisition. 1 ,TE 2 ,…,TE i The magnetic resonance signals are collected and reconstructed to obtain i magnetic resonance images. The signal of the tissue at position r in the i-th image is M TEi , the tissue T2 value at position r can be obtained by fitting the obtained i signal values ​​with the known i TE values. According to formula (2), the three-parameter model used for fitting is:

[0059]

[0060] Among them, M 0 is the initial transverse magnetization vector, and C is the initial image deviation value caused by noise.

[0061] In a high field strength MRI system, such as one with a field strength greater than or equal to 3 Tesla, the actual RF magnetic field at different physical locations varies greatly due to the severe standing wave effect of the MRI imaging object in the RF field and the imperfect transmitting coil hardware, so that the MRI signals at different locations are modulated differently. The accuracy of T2 obtained by only relying on the MRI signal fitting solution will decrease. For example, the signal M at position r xy (r) is subject to the radio frequency field B1 at position r + (r) is modulated with the scanning sequence (such as spin echo). The actual signal at position r can be expressed as M xyReal =f se (B1 + (r))M xy , where f se (B1 + (r)) refers to the response function of the spin echo to the RF field.

[0062] Since the actual RF magnetic fields at different physical locations vary greatly, the magnetic resonance signals at different locations are modulated differently. If T2 is only obtained by fitting the magnetic resonance signals, the accuracy will decrease.

[0063] Based on the above reasons, the present application provides a relaxation time determination method that can improve the accuracy of relaxation time.

[0064] In one embodiment, Figure 1 As shown, a relaxation time determination method is provided. This embodiment uses the method applied to a terminal as an example for illustration. It can be understood that the method can also be applied to a server, and can also be applied to a system including a terminal and a server, and is implemented through the interaction between the terminal and the server.

[0065] In this embodiment, the method includes the following steps:

[0066] S102, obtaining a preset echo time to generate a magnetic resonance image, and each pixel of the magnetic resonance image has a corresponding pixel signal.

[0067] Among them, the echo time can be the time of receiving the magnetic resonance signal echo, which refers to the time from the excitation of the radio frequency pulse to the formation of the maximum echo, which can be represented by TE; the echo time can be a scanning parameter of magnetic resonance, and the echo time can be used to reconstruct the magnetic resonance image. The pixel point can be a point obtained by segmenting the magnetic resonance image, and the magnetic resonance image can contain multiple pixel points. The pixel point can be any pixel point contained in the magnetic resonance image. The pixel signal can be a signal corresponding to the pixel point, for example, it can be a pixel value.

[0068] Exemplarily, a preset echo time can be used to obtain a preset scanning pulse sequence, and the scanning pulse sequence can be further used to scan the object to be scanned to obtain magnetic resonance data, and the magnetic resonance data can be used to reconstruct a magnetic resonance image to obtain a magnetic resonance image corresponding to the above echo time. The pixel points of the reconstructed magnetic resonance image and the pixel signals corresponding to the pixel points can be obtained. In this way, the relaxation time corresponding to the pixel point can be further processed based on the pixel signals corresponding to the pixel points.

[0069] Optionally, a spin echo pulse sequence is used, and a preset echo time is used to collect magnetic resonance data, and the magnetic resonance image is reconstructed using the magnetic resonance data, so that a magnetic resonance image corresponding to the echo time can be obtained. For example, a magnetic resonance image can be acquired by a CPMG (Carr-Purcell-Meiboom-Gill) pulse sequence, and the CPMG pulse sequence can be a spin echo sequence pulse composed of a 90-degree pulse and a series of 180 pulses; or a magnetic resonance image can be acquired by a spin echo sequence pulse composed of other pulses, not limited to a combination of a 90-degree pulse and a 180-degree pulse.

[0070] S104, obtaining multiple candidate relaxation times, and performing image simulation processing using the multiple candidate relaxation times and a preset echo time to obtain simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity; the target emission field intensity is the emission field intensity at the location of the pixel point.

[0071] Among them, the candidate relaxation time can be a relaxation time that may occur during the magnetic resonance process, for example, the candidate relaxation time can be obtained within a possible range of values. Relaxation time refers to the time required for the nuclei that absorb energy to release the absorbed energy after the radio frequency pulse is turned off during the magnetic resonance process, and finally return to the equilibrium state after a certain relaxation process. The relaxation time can be the transverse relaxation time (T2), and the embodiments provided in this application are mainly explained by taking the transverse relaxation time as an example. The target emission field intensity can be the magnetic field intensity corresponding to the position of the pixel point in the radio frequency magnetic field environment. The simulated pixel signal can be a signal corresponding to the pixel point obtained by image simulation, for example, it can be a pixel value obtained by image simulation.

[0072] Exemplarily, all possible relaxation times can be traversed as candidate relaxation times to obtain as many relaxation times as possible as candidate relaxation times; or the candidate relaxation times can be obtained within the range of possible relaxation time values. In this way, the accuracy of obtaining the target relaxation time from multiple candidate relaxation times can be improved. Multiple candidate relaxation times and the same echo time as in step S102 can be used for image simulation processing, and simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity can be obtained. Furthermore, the target relaxation time can be obtained from multiple candidate relaxation times using the simulated pixel signals corresponding to each candidate relaxation time and the pixel signal obtained in S102.

[0073] Optionally, the parameters of the spin echo pulse sequence can be used, and the echo time in S102, n candidate relaxation times, and m emission field intensities can be applied to perform signal simulation to obtain response signals of the m emission field intensities to the spin echo pulse sequence, and the response signals can be used as simulated pixel signals. The target emission field intensity corresponding to the pixel point can be obtained, and the target emission field intensity can be used as an index value to obtain n simulated pixel signals matching the target emission field intensity from the simulated pixel signals corresponding to the m emission field intensities, and the n simulated pixel signals correspond to the n candidate relaxation times one by one, respectively, where m can be equal to n or m is not equal to n.

[0074] Optionally, the emission field intensity at the location of the pixel point can be obtained, and the emission field intensity at the location of the pixel point can be used as the target emission field intensity. Using the parameters of the spin echo pulse sequence, the echo time in S102, the n candidate relaxation times and the target emission field intensity are applied to perform signal simulation to obtain n simulated pixel signals, the n simulated pixel signals correspond to the n candidate relaxation times one by one, and the n simulated pixel signals are all pixel signals that match the target emission field intensity.

[0075] Optionally, the parameters of the spin echo pulse sequence used in step S104 may be the same as or different from the parameters of the spin echo pulse sequence used in step S102.

[0076] S106, determining the degree of difference between each simulated pixel signal and the pixel signal, and taking the candidate relaxation time corresponding to the simulated pixel signal with the smallest degree of difference as the target relaxation time of the pixel point.

[0077] The degree of difference may be a difference calculated between the simulated pixel signal and the pixel signal, for example, a distance value. The target relaxation time may be a relaxation time finally determined for a pixel point, and the target relaxation time is a relaxation time accurately determined for a pixel point within a possible range of values.

[0078] Exemplarily, each simulated pixel signal corresponds one-to-one to each candidate relaxation time, and the degree of difference between each simulated pixel signal and the pixel signal obtained by echo time reconstruction can be obtained, the minimum degree of difference can be determined from multiple degrees of difference, and the simulated pixel signal corresponding to the minimum degree of difference is determined as the target simulated pixel signal, and the candidate relaxation time corresponding to the target simulated pixel signal is used as the target relaxation time.

[0079] For example, n simulated pixel signals can be determined through the above steps S102-S104, and the n simulated pixel signals correspond to n candidate relaxation times one by one. The difference degrees between the n simulated pixel signals and the pixel signals obtained by image reconstruction are calculated to obtain n difference degrees, and the minimum difference degree is determined from the n difference degrees, for example, the difference degree with the kth difference degree being the minimum, and the candidate relaxation time corresponding to the kth difference degree is used as the target relaxation time.

[0080] In this embodiment, a preset echo time is obtained to generate a magnetic resonance image, and each pixel of the magnetic resonance image has a corresponding pixel signal; multiple candidate relaxation times are obtained, and multiple candidate relaxation times and preset echo times are used to perform image simulation processing to obtain simulated pixel signals that correspond to each candidate relaxation time and match the target emission field intensity; the target emission field intensity is the emission field intensity at the location of the pixel point; the degree of difference between each simulated pixel signal and the pixel signal is determined, and the candidate relaxation time corresponding to the simulated pixel signal with the smallest degree of difference is used as the target relaxation time of the pixel point. Compared with conventional technologies, this embodiment can perform image simulation through multiple candidate relaxation times and preset echo times to obtain simulated pixel signals corresponding to the target emission field intensity at the location of the pixel point, and further obtain the degree of difference between the pixel signal corresponding to the magnetic resonance image reconstructed by the preset echo time and the simulated pixel signal, and determine the candidate relaxation time corresponding to the simulated pixel signal with the smallest degree of difference as the target relaxation time. In this way, through the above method, all possible relaxation times are traversed as candidate relaxation times, and processed through image simulation and image reconstruction, and the target relaxation time is obtained from traversing all possible candidate relaxation times. This can reduce the impact of RF magnetic field inhomogeneity on the accuracy of local relaxation time calculation in the image, thereby improving the accuracy of relaxation time.

[0081] In one embodiment, Figure 2 As shown, multiple candidate relaxation times and preset echo times are used to perform image simulation processing to obtain simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity, including:

[0082] S202, obtaining multiple radio frequency pulse flip angles.

[0083] The radio frequency pulse flip angle may be a magnetic field intensity, the radio frequency pulse flip angle may correspond to a transmission field intensity, and the transmission field intensity may be obtained by the radio frequency pulse flip angle.

[0084] S204, performing image simulation processing using multiple candidate relaxation times, multiple radio frequency pulse flip angles, and a preset echo time to obtain a simulation result data set; the simulation result data set includes multiple simulation pixel signals corresponding to different transmission field intensities.

[0085] The simulation result data set may be a set formed by a plurality of simulated pixel signals, different emission field intensities may correspond to different simulated pixel signals, and each simulated pixel signal in the plurality of simulated pixel signals corresponding to each emission field intensities may be matched one by one with each candidate relaxation time. For example, the simulation result data set may be a set formed by m×n simulated pixel signals, wherein m emission field intensities may correspond to n simulated pixel signals, and the n simulated pixel signals may be matched one by one with n candidate relaxation times, and m may be equal to n or m may not be equal to n.

[0086] S206, obtaining, from the simulation result data set, simulation pixel signals corresponding to the candidate relaxation times and matching the target emission field intensity.

[0087] The target emission field strength may be determined according to the radio frequency pulse flip angle and may be the target emission field strength corresponding to the position of the pixel point.

[0088] Exemplarily, all possible emission field intensities may be traversed to obtain multiple emission field intensities. Image simulation processing is performed using multiple candidate relaxation times, multiple radio frequency pulse flip angles, and the same echo time as in step S102 to obtain multiple simulated pixel signals to form a simulation result data set. The emission field intensity image associated with the magnetic resonance device may be obtained by pre-scanning the magnetic resonance device related to S102, and the target emission field intensity corresponding to the radio frequency pulse flip angle at the pixel location may be obtained from the emission field intensity image of the magnetic resonance device. Further, the target emission field intensity may be used as an index value to obtain multiple simulated pixel signals matching the target emission field intensity (index value) from the simulation result data set, wherein, among the multiple simulated pixel signals matching the target emission field intensity, each simulated pixel signal corresponds one-to-one to each candidate relaxation time.

[0089] For example, m RF pulse flip angles can be obtained, and image simulation processing can be performed using n candidate relaxation times, m emission field intensities, and the same echo time as S102 to obtain a simulation result data set; the simulation result data set includes m×n simulation pixel signals, and each of the m RF pulse flip angles (emission field intensities) corresponds to n simulation pixel signals, and the n simulation pixel signals corresponding to different emission field intensities are matched one by one with the n candidate relaxation times, respectively, and m can be equal to n or m is not equal to n. The target emission field intensity at the location of the pixel point is obtained by pre-scanning the magnetic resonance device related to S102. From the simulation result data set, n simulation pixel signals matching the target emission field intensity are obtained.

[0090] In this embodiment, image simulation processing is performed by using multiple candidate relaxation times, multiple radio frequency pulse flip angles, and preset echo times to obtain a simulation result data set, and multiple possible emission field intensities can be used to perform image simulation processing to improve the accuracy of image simulation processing, thereby improving the accuracy of determining the simulation pixel signal corresponding to each candidate relaxation time, and further improving the accuracy of determining the relaxation time. In addition, image simulation processing is performed based on multiple possible emission field intensities, which can cover the target emission field intensities corresponding to each pixel point, and further can be used as an index value to index and obtain each simulation pixel signal with the target emission field intensity, thereby reducing the amount of processing for the above data.

[0091] In one embodiment, Figure 3 As shown, from the simulation result data set, the simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity are obtained, including:

[0092] S302, using the target emission field intensity as an index value, and acquiring a plurality of simulation pixel signals matching the target emission field intensity from a simulation result data set;

[0093] S304 , using a plurality of simulated pixel signals that match the target emission field intensity as simulated pixel signals corresponding to the candidate relaxation times.

[0094] The index value refers to a value used to access and find specific information; for example, the index value may be 10, which can be used to access and find information associated with 10.

[0095] Exemplarily, the target emission field intensity at the location of the pixel point can be used as an index value, and multiple simulated pixel signals matching the target emission field intensity can be obtained from the simulation result data set. And the multiple simulated pixel signals matching the target emission field intensity can be used as the simulated pixel signals corresponding to each candidate relaxation time, that is, the multiple simulated pixel signals matching the target emission field intensity correspond one-to-one to each candidate relaxation time. In this way, it is possible to obtain simulated pixel signals corresponding one-to-one to each candidate relaxation time matching the pixel point. Furthermore, the target relaxation time can be determined from multiple candidate relaxation times using each simulated pixel signal and the pixel signal obtained by image reconstruction, which can improve the accuracy of the relaxation time.

[0096] In this embodiment, image simulation processing is performed based on multiple possible emission field intensities, and the target emission field intensity is used as an index value to obtain each simulated pixel signal that matches the target emission field intensity, thereby reducing the amount of processing for the above data. At the same time, the target emission field intensity of the pixel point is used as an index value to obtain a simulated pixel signal that matches the emission field intensity at the pixel point, which can improve the accuracy of the relaxation time.

[0097] In one embodiment, Figure 4 As shown, multiple emission field strengths are obtained, including:

[0098] S402, using a pre-scan sequence, performing a pre-scan process on a magnetic resonance device associated with the magnetic resonance image to obtain a transmission field distribution image;

[0099] S404: Use the emission field intensities included in the emission field distribution image as a plurality of emission field intensities.

[0100] The pre-scan sequence may be an imaging sequence for scanning an object, and the pre-scan sequence may be an echo imaging sequence, for example, the echo imaging sequence may be a planar echo imaging sequence, or a gradient echo imaging sequence. The emission field distribution image may be an image generated by scanning signals obtained by scanning an imaging sequence, and the emission field distribution image may include multiple emission field intensities.

[0101] Exemplarily, a planar echo imaging sequence can be used to perform pre-scan processing on a magnetic resonance device associated with a magnetic resonance image to obtain a pre-scan signal, and a transmission field distribution image can be generated through the pre-scan signal. All the transmission field intensities contained in the transmission field distribution image can be used as multiple transmission field intensities for image simulation. In this way, by acquiring the transmission field distribution image associated with the magnetic resonance device associated with the magnetic resonance image, and performing image simulation using the transmission field intensities contained in the transmission field distribution image, the target transmission field intensities corresponding to each pixel point can be covered, and image simulation of the target transmission field intensities of each pixel point can be avoided separately, thereby reducing the number of image simulations, thereby improving the image simulation efficiency, and further improving the efficiency of determining the relaxation time.

[0102] In this embodiment, the echo imaging sequence is used to perform pre-scan processing on the magnetic resonance device associated with the magnetic resonance image to obtain a transmission field distribution image, and the transmission field intensity contained in the transmission field distribution image is used as a plurality of transmission field intensities, which can improve the efficiency of determining the relaxation time. Further, the plane echo imaging sequence is used to obtain the transmission field distribution image, which can increase the measurement speed of the magnetic field distribution and further improve the efficiency of determining the relaxation time.

[0103] In one embodiment, Figure 5 As shown, the number of echo times is multiple;

[0104] Obtaining a magnetic resonance image corresponding to a preset echo time includes:

[0105] S502, based on the multiple echo times, generating magnetic resonance images corresponding to the respective echo times; pixel signals corresponding to each pixel point in the multiple magnetic resonance images respectively form a pixel signal set.

[0106] The pixel signal set may be a set formed by multiple pixel signals.

[0107] For example, multiple scanning pulse sequences with different echo times can be used to acquire multiple different magnetic resonance signals, and image reconstruction can be performed to obtain multiple magnetic resonance images. Pixel signals corresponding to the same pixel point in multiple magnetic resonance images can be acquired to obtain pixel signals corresponding to the pixel point in multiple magnetic resonance images, and multiple pixel signals associated with the pixel point can form a pixel signal set.

[0108] Using multiple candidate relaxation times and preset echo times to perform image simulation processing, a simulated pixel signal corresponding to each candidate relaxation time and matching the target emission field intensity is obtained, including:

[0109] S504, using multiple candidate relaxation times and multiple echo times to perform image simulation processing, to obtain a set of simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity; each simulated pixel signal set contains multiple simulated pixel signals, each simulated pixel signal is obtained by performing image simulation processing with different echo times.

[0110] The simulated pixel signal set may be a set formed by multiple simulated pixel signals. The simulated pixel signal set may include simulated pixel signals corresponding to multiple echo times, and each simulated pixel signal included in the simulated pixel signal may be obtained by performing image simulation processing at different echo times. For example, if the number of echo times is i, the simulated pixel signal set may include i simulated pixel signals, which correspond to the i echo times one by one.

[0111] Exemplarily, multiple candidate relaxation times and multiple echo times identical to those in S502 can be used to perform image simulation processing, and a set of simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity can be obtained. Further, the target relaxation time can be obtained from the multiple candidate relaxation times using the set of simulated pixel signals corresponding to each candidate relaxation time and the set of pixel signals obtained in S502.

[0112] Optionally, the parameters of the spin echo pulse sequence can be used, and the i echo times, n candidate relaxation times and emission field strength in S502 are applied to perform signal simulation to obtain n simulated pixel signal sets, each of which contains i simulated pixel signals, and the i simulated pixel signals are respectively obtained by image simulation of i echo times. Among them, m can be equal to i or m is not equal to i.

[0113] Optionally, the parameters of the spin echo pulse sequence can be used, and the i echo times, n candidate relaxation times, and m emission field intensities in S502 can be applied to perform signal simulation to obtain the response signals of the m emission field intensities to the spin echo pulse sequence, and the response signals can be used as simulated pixel signals. The simulation result data can be a three-dimensional data, and the three dimensions of this three-dimensional data correspond to the echo time, the candidate relaxation time, and the emission field intensity. The target emission field intensity corresponding to the pixel point can be obtained, and the target emission field intensity is used as an index value. From the dimension of the emission field intensity of the three-dimensional data, two-dimensional data can be obtained, and the two dimensions of this two-dimensional data represent the echo time and the candidate relaxation time respectively; that is, using the target emission field intensity as an index value, n simulated pixel signal sets matching the target emission field intensity are indexed from the three-dimensional data, and each simulated pixel signal set contains i simulated pixel signals, and the i simulated pixel signals are respectively obtained by image simulation of i echo times. Among them, the values ​​of i, m, and n can be all the same, partially the same, or all different.

[0114] Optionally, the emission field intensity at the location of the pixel point can be obtained, and the emission field intensity at the location of the pixel point can be used as the target emission field intensity. Using the parameters of the spin echo pulse sequence, the i echo times, n candidate relaxation times and target emission field intensity in S502 are applied to perform signal simulation to obtain n simulated pixel signal sets, the n simulated pixel signal sets correspond to the n candidate relaxation times one by one, and the n simulated pixel signal sets are all pixel signals that match the target emission field intensity, and each simulated pixel signal set contains i simulated pixel signals, and the i simulated pixel signals are obtained by image simulation of i echo times. Among them, the values ​​of i, m, and n can be all the same, partially the same, or all different.

[0115] Determine the degree of difference between each simulated pixel signal and the pixel signal, and use the candidate relaxation time corresponding to the simulated pixel signal with the smallest degree of difference as the target relaxation time of the pixel point, including:

[0116] S506, determining the degree of difference between each simulated pixel signal set and the pixel signal set, and taking the candidate relaxation time corresponding to the simulated pixel signal set with the smallest degree of difference as the target relaxation time of the pixel point.

[0117] The degree of difference may be the distance between the sets, or may be the degree of difference determined by the similarity between the simulated pixel signal set and the pixel signal set. If the degree of difference is determined based on the similarity, the greater the similarity, the smaller the degree of difference, and the smaller the similarity, the greater the degree of difference.

[0118] Exemplarily, each simulated pixel signal set corresponds one-to-one to each candidate relaxation time, and the degree of difference between each simulated pixel signal set and the pixel signal set can be obtained, the minimum degree of difference can be determined from multiple degrees of difference, and the simulated pixel signal set corresponding to the minimum degree of difference can be determined as the target simulated pixel signal set, and the candidate relaxation time corresponding to the target simulated pixel signal set can be used as the target relaxation time.

[0119] For example, n simulated pixel signal sets can be determined through the above steps S502-S504, and the n simulated pixel signal sets correspond to the n candidate relaxation times one by one. The difference between the n simulated pixel signal sets and the pixel signal set obtained by image reconstruction is obtained, and the minimum difference degree is determined from the n difference degrees.

[0120] Optionally, a norm between the simulated pixel signal set and the pixel signal set can be calculated, and the norm between the sets can be used as the difference degree. The smallest norm means the smallest difference degree, or any other method of calculating the difference degree between data points can be used.

[0121] Optionally, the method for obtaining the degree of difference between the pixel signal set and the simulated pixel signal set can be to fit the pixel signal set and the simulated pixel signal set respectively using the same mathematical model, and an additional constant C needs to be added to the pixel signal set during fitting. If the parameters obtained by fitting the simulated pixel signal set are closest to the constant C, then the degree of difference between the simulated pixel signal set and the pixel signal set is the smallest.

[0122] In this embodiment, a plurality of pre-set echo times are obtained to generate magnetic resonance images corresponding to each echo time, and pixel signals corresponding to the pixel points in the plurality of magnetic resonance images are obtained to form a pixel signal set; and image simulation processing is performed using a plurality of candidate relaxation times and a plurality of echo times to obtain a simulated pixel signal set that corresponds to each candidate relaxation time and matches the target emission field intensity; further, the degree of difference between each simulated pixel signal set and the pixel signal set can be obtained, and the candidate relaxation time corresponding to the simulated pixel signal set with the smallest degree of difference is determined as the target relaxation time. In this way, a pixel signal set and a simulated pixel signal set are obtained based on a plurality of echo times, and the degree of difference between the two sets is compared, which is conducive to improving the accuracy of the degree of difference compared to comparing the degree of difference between a single pixel signal and a single simulated pixel signal, thereby improving the accuracy of the relaxation time.

[0123] In one embodiment, determining the degree of difference between each set of simulated pixel signals and the set of pixel signals includes:

[0124] Obtaining a current simulation pixel signal set and a set distance from a pixel signal set; the current simulation pixel signal set is any simulation pixel signal set;

[0125] The set distance is taken as the difference between the current simulation pixel signal set and the pixel signal set.

[0126] The current simulated pixel signal set may be any simulated pixel signal set; that is, for any simulated pixel signal set, the method of this embodiment may be applied to calculate the degree of difference. The set distance may be the distance value between sets, for example, the set distance may be represented by a norm between sets.

[0127] Exemplarily, for any simulated pixel signal set, a set distance between the simulated pixel signal set and the pixel signal set is obtained, and the set distance is taken as the difference degree between the simulated pixel signal set and the pixel signal set.

[0128] In this embodiment, by taking the set distance as the degree of difference, the degree of difference between the current simulation pixel signal set and the pixel signal set can be accurately obtained, thereby improving the accuracy of the relaxation time.

[0129] In one embodiment, image simulation processing is performed using multiple candidate relaxation times and a preset echo time to obtain simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity, including:

[0130] Get the target emission field intensity corresponding to the pixel point;

[0131] Image simulation processing is performed using multiple candidate relaxation times, target emission field intensities, and preset echo times to obtain simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity.

[0132] Exemplarily, the emission field intensity at the location of the pixel point can be obtained, and the emission field intensity at the location of the pixel point can be used as the target emission field intensity. Using the parameters of the spin echo pulse sequence, the echo time in the image reconstruction process, the n candidate relaxation times and the target emission field intensity are used to perform signal simulation to obtain n simulated pixel signals, the n simulated pixel signals correspond to the n candidate relaxation times one by one, and the n simulated pixel signals are all pixel signals that match the target emission field intensity.

[0133] In this embodiment, the target emission field intensity at the pixel location is predetermined, and image simulation is performed based on the predetermined target emission field intensity, reducing the processing steps of indexing the target emission field intensity as an index value, thereby improving the efficiency of determining the relaxation time corresponding to the pixel point.

[0134] In one embodiment, obtaining the target emission field intensity corresponding to the pixel point includes:

[0135] Using a pre-scan sequence, pre-scanning a magnetic resonance device associated with the magnetic resonance image is performed to obtain a transmission field distribution image;

[0136] Obtain pixel data of pixels in the emission field distribution image;

[0137] The pixel data is used as the target emission field intensity.

[0138] Exemplarily, a pre-scan sequence (e.g., a planar echo imaging sequence) may be used to perform pre-scan processing on a magnetic resonance device associated with a magnetic resonance image to obtain a pre-scan signal, and a transmission field distribution image may be generated by the pre-scan signal. Pixel point data (e.g., pixel value) of a pixel point in the transmission field distribution image may be obtained, and the pixel point data may be used as a target transmission field intensity.

[0139] In this embodiment, the echo imaging sequence can be used to perform pre-scanning processing on the magnetic resonance device associated with the magnetic resonance image to obtain an emission field distribution image, and the pixel data of the pixel point in the emission field distribution image is used as the target emission field intensity, and the target emission field intensity can be used as an index value for indexing, or the target emission field intensity can be used for image simulation, both of which can improve the efficiency of determining the relaxation time. At the same time, by performing a pre-scan before scanning the relaxation time measurement sequence, the optimization scanning method is optimized to a certain extent, which can improve the accuracy of the relaxation time compared to the method of determining the relaxation time in the traditional technology.

[0140] In one embodiment, the target relaxation time is the transverse relaxation time.

[0141] In a specific embodiment, a method for determining a transverse relaxation time is provided, the method comprising the following steps:

[0142] Before starting the T2 (transverse relaxation time) measurement sequence, a pre-scan is performed: an emission field distribution image of the magnetic resonance system is obtained using an echo imaging sequence. The emission field distribution image can be obtained according to any existing echo imaging sequence, which is not described in detail in this method. The emission field distribution image is denoted as B1Map, which can be a collection of two-dimensional images or a three-dimensional image. The pixel value B1Map(r) at position r in the image is the emission field intensity at position r, where position r is the location of the pixel. The emission field distribution image B1Map is stored in memory or hard disk.

[0143] A CPMG pulse sequence, i.e., a spin echo pulse sequence consisting of a 90-degree pulse and a series of 180-degree pulses, or other pulse sequences are used to collect magnetic resonance data of i different echo times TE and reconstruct the images respectively to obtain i magnetic resonance images. The radio frequency pulse flip angle of the spin echo pulse sequence can be any combination, not limited to the combination of 90-180 degrees.

[0144] The signal simulation is performed according to the parameters of the above spin echo pulse sequence, and i different echo times TE, n different candidate relaxation time T2 values, and m different transmission field intensities B1 are used in the simulation. + Value (i.e. change the flip angle of the pulse sequence). Image simulation obtains the emission field intensity B1 + The response signal fse(B1 m + ) t2_n The simulation result data is a three-dimensional data data, and the three dimensions correspond to different transmit field B1+ values, different TE values ​​(i.e. different spin echoes), and different T2 values. The storage module stores this three-dimensional data in the memory or hard disk.

[0145] Get the signal value S of the pixel at position r in the i magnetic resonance image 1 (r), S 2 (r),…,S i (r), these signal values ​​are arranged in ascending order of echo time TE value to form a vector S(r), S(r) = [S 1 (r), S 2 (r),…,S i (r)]. Store S(r) to memory or hard disk.

[0146] Get B1Map(r) and use it as the index value to get the two-dimensional data data1 from the dimension one of the three-dimensional data data. The two dimensions of data1 represent different TE values ​​and different T2 values. Get n groups of data from the dimension two (different T2 values) in data1. Each group of data is a vector S(T2 n ).

[0147] S(r) and S(T2 n ) one by one until the kth S(T2 with the smallest difference is found k ). T2 k That is, the estimated T2 value of the tissue at position r. The spatial mapping image of the T2 value is T2Map, which is an image obtained based on the T2 value of the tissue at position r.

[0148] Compare S(r) with S(T2 n) can be used to calculate a norm |S(r)-S(T2 n )|, the least-norm is the minimum difference, or it can be any way to calculate the difference between data points.

[0149] Compare S(r) with S(T2 n ) can be used to compare S(r) and S(T2 n ) are fitted using the same model. When fitting S(r), an additional constant C needs to be added. If S(T2 n )The parameters obtained by fitting are closest to the constant C and the difference is the smallest.

[0150] In this embodiment, the relaxation time T2 is determined by the transverse relaxation time determination method provided in the present application, which reduces the influence of the radio frequency magnetic field inhomogeneity on the accuracy of local T2 calculation in the image, improves the accuracy of the transverse relaxation time, and further can use the transverse relaxation time for magnetic resonance imaging, thereby improving the accuracy of the magnetic resonance image obtained by magnetic resonance imaging.

[0151] In one embodiment, a magnetic resonance quantitative imaging method is provided, the method comprising:

[0152] Acquire a plurality of magnetic resonance images corresponding to the echo times, the magnetic resonance image comprising a plurality of pixel points, each pixel point having a corresponding pixel signal;

[0153] Acquire multiple candidate relaxation times, and use the multiple candidate relaxation times and echo times to perform simulation processing to obtain simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity; the target emission field intensity is the emission field intensity at the location of the pixel point;

[0154] Performing a traversal operation on the simulated pixel signal to determine a simulated pixel signal matching the pixel signal, and determining a target relaxation time of the pixel point according to the simulated pixel signal matching the pixel signal; and,

[0155] Displays the reference echo signal plot corresponding to the target relaxation time.

[0156] The simulated pixel signal that matches the pixel signal may refer to a simulated pixel signal whose matching degree is within a preset range.

[0157] The reference echo signal graph may be an image formed by ideal signal values ​​of each echo. For example, the ideal signal value of each echo is formed by the target relaxation time corresponding to each pixel point to form the reference echo signal graph.

[0158] In this embodiment, the relaxation time is determined by the relaxation time determination method provided in the present application, and the target relaxation time is used to determine the ideal signal value of each echo of the ideal transmission field (100%) corresponding to each pixel point to form a reference echo signal graph, thereby solving the problem of uneven magnetic field distribution graph obtained by high-field magnetic resonance systems and low reference value for doctors, and further improving the accuracy of the magnetic resonance images obtained by magnetic resonance imaging.

[0159] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0160] Based on the same inventive concept, the embodiments of the present application also provide a relaxation time determination device for implementing the relaxation time determination method involved above, and also provide a magnetic resonance quantitative imaging device for implementing the magnetic resonance quantitative imaging method involved above. The implementation scheme for solving the problem provided by the above-mentioned device is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in the one or more relaxation time determination device embodiments provided below can refer to the limitations on the relaxation time determination method above, and the specific limitations in the one or more magnetic resonance quantitative imaging device embodiments provided can refer to the limitations on the magnetic resonance quantitative imaging method above, which will not be repeated here.

[0161] In one embodiment, Figure 6 As shown, a relaxation time determination device 600 is provided, comprising: a pixel signal determination module 610, a simulation signal determination module 620 and a relaxation time determination module 630, wherein:

[0162] The pixel signal determination module 610 is used to obtain a preset echo time to generate a magnetic resonance image, wherein the magnetic resonance image includes a plurality of pixels, each of which has a corresponding pixel signal;

[0163] The simulation signal determination module 620 is used to obtain multiple candidate relaxation times, and use the multiple candidate relaxation times and the preset echo time to perform image simulation processing to obtain a simulation pixel signal corresponding to each candidate relaxation time and matching the target emission field intensity; the target emission field intensity is the emission field intensity at the location of the pixel point;

[0164] The relaxation time determination module 630 is used to determine the difference between each simulated pixel signal and the pixel signal, and use the candidate relaxation time corresponding to the simulated pixel signal with the smallest difference as the target relaxation time of the pixel point.

[0165] In one embodiment, the simulation signal determination module includes a radio frequency pulse flip angle unit, an image simulation processing unit and a target simulation pixel signal unit.

[0166] The RF pulse flip angle unit is used to obtain multiple RF pulse flip angles. The image simulation processing unit is used to perform image simulation processing using multiple candidate relaxation times, multiple emission field intensities, and preset echo times to obtain a simulation result data set; the simulation result data set includes multiple simulation pixel signals corresponding to different emission field intensities; each simulation pixel signal is matched with each candidate relaxation time. The target simulation pixel signal unit is used to obtain, from the simulation result data set, simulation pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity.

[0167] In one embodiment, the target simulated pixel signal unit includes an index value determination unit and a simulated pixel signal determination unit.

[0168] The index value determination unit is used to use the target emission field intensity as the index value, and obtain multiple simulated pixel signals matching the target emission field intensity from the simulation result data set. The simulated pixel signal determination unit is used to use the multiple simulated pixel signals matching the target emission field intensity as the simulated pixel signals corresponding to each candidate relaxation time.

[0169] In one embodiment, the number of echo times is multiple. The pixel signal determination module includes a pixel signal set determination unit. The simulation signal determination module includes a simulation pixel signal set unit. The relaxation time determination module includes a set difference unit.

[0170] The pixel signal set determination unit is used to generate a magnetic resonance image corresponding to each echo time based on multiple echo times; the pixel signals corresponding to each pixel point in the multiple magnetic resonance images form a pixel signal set. The simulation pixel signal set unit is used to use multiple candidate relaxation times and multiple echo times to perform image simulation processing to obtain a simulation pixel signal set corresponding to each candidate relaxation time and matching the target emission field intensity; each simulation pixel signal set contains multiple simulation pixel signals, and each simulation pixel signal is obtained by performing image simulation processing at different echo times. The set difference unit is used to determine the degree of difference between each simulation pixel signal set and the pixel signal set, and the candidate relaxation time corresponding to the simulation pixel signal set with the smallest degree of difference is used as the target relaxation time of the pixel point.

[0171] In one embodiment, the set difference unit includes a set distance unit and a difference degree acquisition unit.

[0172] The set distance unit is used to obtain the set distance between the current simulated pixel signal set and the pixel signal set; the current simulated pixel signal set is any simulated pixel signal set. The difference degree acquisition unit is used to use the set distance as the difference degree between the current simulated pixel signal set and the pixel signal set.

[0173] In one embodiment, the simulation signal determination module includes a target emission field intensity determination unit and an image simulation unit.

[0174] The target emission field intensity determination unit is used to obtain the target emission field intensity corresponding to the pixel point. The image simulation unit is used to perform image simulation processing using multiple candidate relaxation times, target emission field intensity and preset echo time to obtain simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity.

[0175] In one embodiment, the target emission field intensity determination unit includes a pre-scan sequence unit, a pixel point data acquisition unit and a target intensity determination unit.

[0176] The pre-scan sequence unit is used to perform pre-scan processing on the magnetic resonance device associated with the magnetic resonance image using the pre-scan sequence to obtain the emission field distribution image. The pixel point data acquisition unit is used to obtain the pixel point data of the pixel point in the emission field distribution image. The target intensity determination unit is used to use the pixel point data as the target emission field intensity.

[0177] In one embodiment, a magnetic resonance quantitative imaging device is provided, comprising: a magnetic resonance imaging module, a simulation processing module, a target relaxation time module and a signal graph display module, wherein:

[0178] The magnetic resonance imaging module is used to obtain magnetic resonance images corresponding to multiple echo times, the magnetic resonance image includes multiple pixel points, and each pixel point has a corresponding pixel signal;

[0179] The simulation processing module is used to obtain multiple candidate relaxation times, and use the multiple candidate relaxation times and echo times for simulation processing to obtain simulated pixel signals corresponding to each candidate relaxation time and matching the target emission field intensity; the target emission field intensity is the emission field intensity at the location of the pixel point;

[0180] The target relaxation time module is used to perform a traversal operation on the simulated pixel signal to determine a simulated pixel signal matching the pixel signal, and determine a target relaxation time of the pixel point according to the simulated pixel signal matching the pixel signal; and,

[0181] The signal graph display module is used to display the reference echo signal graph corresponding to the target relaxation time.

[0182] Each module in the relaxation time determination device and magnetic resonance quantitative imaging device can be implemented in whole or in part by software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each module.

[0183] 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 7 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. 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 echo time, magnetic resonance image, candidate relaxation time, and emission field intensity. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication 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 relaxation time determination method and a magnetic resonance quantitative imaging method are implemented.

[0184] Those skilled in the art will understand that Figure 7The 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.

[0185] 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.

[0186] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0187] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0188] 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 the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0189] The technical features of the above embodiments may be combined arbitrarily. 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.

[0190] The above-described 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 present 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 protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for determining relaxation time, characterized in that: The method comprises: Acquire a magnetic resonance image corresponding to a preset echo time, wherein the magnetic resonance image includes a plurality of pixel points, each of which has a corresponding pixel signal; Acquire multiple candidate relaxation times, and use the multiple candidate relaxation times and the preset echo time to perform image simulation processing to obtain simulated pixel signals corresponding to each of the candidate relaxation times and matching the target emission field intensity; the target emission field intensity is the emission field intensity at the location of the pixel point; The degree of difference between each of the simulated pixel signals and the pixel signal is determined, and the candidate relaxation time corresponding to the simulated pixel signal with the smallest degree of difference is used as the target relaxation time of the pixel point.

2. The method according to claim 1, characterized in that The method of performing image simulation processing by using the plurality of candidate relaxation times and the preset echo time to obtain simulated pixel signals corresponding to the candidate relaxation times and matching the target emission field intensity includes: Acquire multiple radio frequency pulse flip angles; Performing image simulation processing using the multiple candidate relaxation times, the multiple radio frequency pulse flip angles, and the preset echo time to obtain a simulation result data set; the simulation result data set includes multiple simulation pixel signals corresponding to different transmission field intensities; From the simulation result data set, a simulation pixel signal corresponding to each of the candidate relaxation times and matching the target emission field intensity is obtained; the target emission field intensity corresponds to any one of the multiple radio frequency pulse flip angles.

3. The method according to claim 2, characterized in that The step of obtaining, from the simulation result data set, simulated pixel signals corresponding to the candidate relaxation times and matching the target emission field intensity comprises: Taking the target emission field intensity as an index value, acquiring a plurality of simulation pixel signals matching the target emission field intensity from the simulation result data set; A plurality of simulated pixel signals matching the target emission field intensity are used as simulated pixel signals corresponding to the candidate relaxation times.

4. The method according to claim 1, characterized in that: The number of the echo times is multiple; The step of acquiring a magnetic resonance image corresponding to a preset echo time includes: Based on the multiple echo times, a magnetic resonance image corresponding to each of the echo times is generated; pixel signals corresponding to each of the pixel points in the multiple magnetic resonance images respectively form a pixel signal set; The method of performing image simulation processing by using the plurality of candidate relaxation times and the preset echo time to obtain simulated pixel signals corresponding to the candidate relaxation times and matching the target emission field intensity includes: Using the multiple candidate relaxation times and the multiple echo times to perform image simulation processing, a set of simulated pixel signals corresponding to each of the candidate relaxation times and matching the target emission field intensity is obtained; each of the simulated pixel signal sets includes multiple simulated pixel signals, each of which is obtained by performing image simulation processing at different echo times; The step of determining the degree of difference between each of the simulated pixel signals and the pixel signal, and taking the candidate relaxation time corresponding to the simulated pixel signal having the smallest degree of difference as the target relaxation time of the pixel point, comprises: The degree of difference between each of the simulated pixel signal sets and the pixel signal set is determined, and the candidate relaxation time corresponding to the simulated pixel signal set with the smallest degree of difference is used as the target relaxation time of the pixel point.

5. The method according to claim 4, characterized in that The determining the degree of difference between each of the simulated pixel signal sets and the pixel signal set comprises: Obtaining a current simulation pixel signal set and a set distance between the current simulation pixel signal set and the pixel signal set; the current simulation pixel signal set is any simulation pixel signal set; The set distance is used as the difference between the current simulation pixel signal set and the pixel signal set.

6. The method according to claim 1, characterized in that The method of performing image simulation processing by using the plurality of candidate relaxation times and the preset echo time to obtain simulated pixel signals corresponding to the candidate relaxation times and matching the target emission field intensity includes: Obtaining the target emission field intensity corresponding to the pixel point; Image simulation processing is performed using the multiple candidate relaxation times, the target emission field intensity, and the preset echo time to obtain simulated pixel signals corresponding to the candidate relaxation times and matching the target emission field intensity.

7. The method according to claim 6, characterized in that The obtaining the target emission field intensity corresponding to the pixel point includes: Using a pre-scan sequence, pre-scanning a magnetic resonance device associated with the magnetic resonance image to obtain a transmission field distribution image; Acquire pixel data of the pixel in the emission field distribution image; The pixel point data is used as the target emission field intensity.

8. The method according to any one of claims 1 to 7, characterized in that: The target relaxation time is the transverse relaxation time.

9. A magnetic resonance quantitative imaging method, characterized in that: The method comprises: Acquire a plurality of magnetic resonance images corresponding to echo times, wherein the magnetic resonance image comprises a plurality of pixel points, each of the pixel points having a corresponding pixel signal; Acquire multiple candidate relaxation times, and use the multiple candidate relaxation times and the echo time to perform simulation processing to obtain simulated pixel signals corresponding to each of the candidate relaxation times and matching the target emission field intensity; the target emission field intensity is the emission field intensity at the location of the pixel point; Performing a traversal operation on the simulated pixel signal to determine a simulated pixel signal matching the pixel signal, and determining a target relaxation time of the pixel point according to the simulated pixel signal matching the pixel signal; and, A reference echo signal graph corresponding to the target relaxation time is displayed.

10. A relaxation time determination device, characterized in that: The device comprises: A pixel signal determination module, used to obtain a magnetic resonance image corresponding to a preset echo time, wherein the magnetic resonance image includes a plurality of pixel points, each of which has a corresponding pixel signal; A simulation signal determination module, used to obtain a plurality of candidate relaxation times, and use the plurality of candidate relaxation times and the preset echo time to perform image simulation processing to obtain a simulation pixel signal corresponding to each of the candidate relaxation times and matching a target emission field intensity; the target emission field intensity is the emission field intensity at the location of the pixel point; The relaxation time determination module is used to determine the difference between each of the simulated pixel signals and the pixel signal, and to use the candidate relaxation time corresponding to the simulated pixel signal with the smallest difference as the target relaxation time of the pixel point.

Images