Method, device and equipment for acquiring dispersion sensitive factors of target acquisition sequence

Abstract

The invention relates to the technical field of scanning imaging, and provides a method, a device and equipment for obtaining dispersion sensitive factors of a target acquisition sequence, and the method comprises the steps: obtaining gradient vectors which correspond to current excitation and are located on each axis of a rotating coordinate system of the target acquisition sequence under the condition of non-first excitation sampling; performing decomposition processing on each gradient vector to obtain a dispersion sensitive factor of each gradient vector on each axis of a static coordinate system of the target acquisition sequence; and performing summation processing on the dispersion sensitive factors on each axis of the static coordinate system to obtain the dispersion sensitive factor corresponding to the current excitation.

Description

Technical Field

[0001] The present application relates to the field of scanning imaging technology, and in particular to a method, device and equipment for acquiring a diffusion sensitivity factor of a target acquisition sequence. Background Art

[0002] The diffusion sensitivity factor, also known as the b value or b-value, is an important working parameter obtained based on the sequence waveform of the magnetic resonance acquisition sequence. It is also an important reference indicator for measuring the diffusion ability of the magnetic resonance acquisition sequence for water molecules.

[0003] However, in the process of obtaining the diffusion sensitivity factor of the non-Cartesian acquisition sequence based on the existing technology, it is not considered that a wave component in the sequence waveform of this type of sequence will rotate at a specific angle as the number of excitations increases. This makes the diffusion sensitivity factor of the non-Cartesian acquisition sequence obtained based on the existing technology usually have the problem of low accuracy. Summary of the invention

[0004] Based on this, it is necessary to provide a method, device and equipment for obtaining the diffusion sensitivity factor of a target acquisition sequence in response to the above technical problems.

[0005] In a first aspect, the present application provides a method for obtaining a diffusion sensitivity factor of a target acquisition sequence, the method comprising:

[0006] In the case of non-first excitation sampling, the gradient vector corresponding to the current excitation on each axis of the rotating coordinate system of the target acquisition sequence is obtained;

[0007] Decomposing each of the gradient vectors respectively to obtain a diffusion sensitivity factor of each of the gradient vectors on each axis of the stationary coordinate system of the target acquisition sequence;

[0008] The diffusion sensitivity factors on each axis of the stationary coordinate system are summed to obtain the diffusion sensitivity factor corresponding to the current excitation.

[0009] In one embodiment, the target acquisition sequence is a non-Cartesian acquisition sequence; and the decomposing each of the gradient vectors to obtain the diffusion sensitivity factor of each of the second gradient vectors on each axis of the stationary coordinate system of the target acquisition sequence comprises:

[0010] Based on the parallelogram rule, a first mapping vector, a second mapping vector, and a third mapping vector of each gradient vector in the stationary coordinate system are respectively obtained; and a diffusion sensitivity factor on each axis of the stationary coordinate system is obtained according to each first mapping vector, each second mapping vector, and each third mapping vector.

[0011] In one embodiment, acquiring the dispersion sensitivity factor on each axis of the stationary coordinate system according to each of the first mapping vectors, each of the second mapping vectors, and each of the third mapping vectors includes:

[0012] The first mapping vectors, the second mapping vectors, and the third mapping vectors are summed up respectively to obtain the gradient vector sums on the axes of the stationary coordinate system; and the diffusion sensitivity factors on the axes of the stationary coordinate system are obtained based on the gradient vector sums.

[0013] In one embodiment, the obtaining the diffusion sensitivity factor on each axis of the stationary coordinate system based on the sum of each gradient vector includes:

[0014] Based on the sum of each of the gradient vectors, the gradient amplitude of the current gradient application time period is determined; the duration of the current gradient application time period, the gyromagnetic ratio, and the gradient interval between the bipolar gradients corresponding to the current excitation are obtained; and the diffusion sensitivity factor on each axis of the stationary coordinate system is obtained according to each of the gradient amplitudes, the duration, the gyromagnetic ratio, and the gradient interval.

[0015] In one embodiment, the position of the stationary coordinate system is relatively set based on the position of the region of interest of the scanned imaging; the method further comprises:

[0016] In the case of first excitation sampling, the initial gradient vectors corresponding to the first excitation on the axes of the stationary coordinate system of the target acquisition sequence are obtained; and the initial gradient vectors are summed to obtain the initial diffusion sensitivity factor corresponding to the first excitation.

[0017] In one embodiment, the method further comprises:

[0018] In the case of the non-first excitation sampling and the target acquisition sequence being a propeller sequence, the current rotation angle of the rotating coordinate system is determined based on a preset angle and the number of excitations corresponding to the target acquisition sequence.

[0019] In a second aspect, the present application further provides a device for acquiring a diffusion sensitivity factor of a target acquisition sequence, the device comprising:

[0020] A module for acquiring gradient vectors of each axis, used for acquiring the gradient vectors of each axis of the rotating coordinate system of the target acquisition sequence corresponding to the current excitation in the case of non-first excitation sampling;

[0021] A diffusion sensitivity factor acquisition module for each axis is used to decompose each of the gradient vectors to obtain a diffusion sensitivity factor of each of the gradient vectors on each axis of the stationary coordinate system of the target acquisition sequence;

[0022] The sequential diffusion sensitivity factor output module is used to sum the diffusion sensitivity factors on each axis of the stationary coordinate system to obtain the diffusion sensitivity factor corresponding to the current excitation.

[0023] In a third aspect, the present application further provides a computer device, wherein the computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0024] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0025] In a fifth aspect, the present application further provides a computer program product, wherein the computer program product comprises a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0026] The above-mentioned method, device and equipment for obtaining the diffusion sensitivity factor of the target acquisition sequence, first, in the case of non-first excitation sampling, obtain the gradient vector on each axis of the rotating coordinate system of the target acquisition sequence corresponding to the current excitation. Then, each gradient vector is decomposed and processed respectively to obtain the diffusion sensitivity factor of each gradient vector on each axis of the stationary coordinate system of the target acquisition sequence. Finally, the diffusion sensitivity factor on each axis of the stationary coordinate system is summed to obtain the diffusion sensitivity factor corresponding to the current excitation. The present application decomposes the gradient vector on each axis of the rotating coordinate system of the target acquisition sequence corresponding to the current excitation into mapping vectors on each axis of the stationary coordinate system of the target acquisition sequence, obtains the diffusion sensitivity factor corresponding to each axis of the stationary coordinate system of the target acquisition sequence based on the sum of the mapping vectors corresponding to each axis of the stationary coordinate system, and obtains the diffusion sensitivity factor corresponding to the current excitation by summing the diffusion sensitivity factors corresponding to each axis of the stationary coordinate system of the target acquisition sequence, which can not only improve the data accuracy of the diffusion sensitivity factor of the non-Cartesian acquisition sequence obtained, but also effectively improve the imaging quality of the non-Cartesian acquisition sequence. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A diagram of an application environment of a method for acquiring a diffusion sensitivity factor of a target acquisition sequence provided in an embodiment;

[0028] Figure 2 A schematic diagram of a specific implementation flow of a method for acquiring a diffusion sensitivity factor of a target acquisition sequence provided in an embodiment;

[0029] Figure 3A schematic flow chart of a specific method for obtaining a dispersion sensitivity factor on each axis of a stationary coordinate system according to a mapping vector provided in an embodiment;

[0030] Figure 4 A schematic diagram of a specific implementation method for obtaining a mapping vector of a gradient vector in a rotating coordinate system on each axis of a stationary coordinate system provided in an embodiment;

[0031] Figure 5 A schematic flow chart of a specific method for obtaining a dispersion sensitivity factor on each axis of a stationary coordinate system provided in an embodiment;

[0032] Figure 6 A schematic flow chart of a specific method for calculating the dispersion sensitivity factor on each axis of a stationary coordinate system provided in one embodiment;

[0033] Figure 7 A schematic flow chart of a specific method for obtaining an initial diffusion sensitivity factor corresponding to a first excitation provided in an embodiment;

[0034] Figure 8 It is a structural block diagram of a device for acquiring a diffusion sensitivity factor of a target acquisition sequence provided in an embodiment;

[0035] Fig. 9 An internal structure diagram of a computer device provided in one embodiment;

[0036] Fig.10 The internal structure diagram of a computer device provided in another embodiment. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present application. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0038] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0039] The method for obtaining the diffusion sensitivity factor of the target acquisition sequence provided in the embodiment of the present application can be applied to a terminal or a server for execution. The terminal can communicate with the server through a network; the data storage system can store data that the server needs to process; the data storage system can be integrated on the server, or placed on the cloud or other network servers; the terminal can be, but is not limited to, various personal computers, laptops, smart phones, and tablet computers; the server can be implemented as an independent server or a server cluster composed of multiple servers.

[0040] In one embodiment, Figure 1 As shown, a method for obtaining a diffusion sensitivity factor of a target acquisition sequence is provided, comprising the following steps:

[0041] Step S110 , in the case of non-first excitation sampling, obtaining the gradient vector corresponding to the current excitation on each axis of the rotating coordinate system of the target acquisition sequence.

[0042] In this step, excitation sampling refers to a signal acquisition process in which an excitation radio frequency pulse is used to excite a macroscopic magnetization vector in a magnetic resonance system (for example, a macroscopic magnetization vector generated by hydrogen protons of a measured object) so that the macroscopic magnetization vector precesses around the direction of a magnetic field, and a target acquisition sequence is used to acquire magnetic resonance signals generated by the macroscopic magnetization vector, and a magnetic resonance image can be acquired by reconstructing the aforementioned magnetic resonance signals; non-first excitation sampling refers to the aforementioned signal acquisition process not being performed for the first time in a magnetic resonance system; a target acquisition sequence refers to an acquisition sequence used to acquire magnetic resonance signals generated by the macroscopic magnetization vector in the aforementioned signal acquisition process; a rotating coordinate system of a target acquisition sequence refers to a rotating coordinate system used to acquire a gradient vector corresponding to a current excitation in the case of non-first excitation sampling; a gradient vector on each axis refers to a gradient vector generated on each axis of a rotating coordinate system of a target acquisition sequence in the case of non-first excitation sampling, corresponding to the current excitation.

[0043] Specifically, the specific type of the target acquisition sequence may be a non-Cartesian acquisition sequence, in which a wavelet in the sequence waveform of the sequence may rotate at a specific angle as the number of excitations increases; the specific expression of the rotating coordinate system of the target acquisition sequence may be a spatial rectangular coordinate system corresponding to the target acquisition sequence, which may rotate at a specific angle as the number of excitations increases.

[0044] In practical applications, the gradient vectors on each axis of the rotating coordinate system of the target acquisition sequence can be used to characterize the gradient vector values ​​of the readout gradient, damage gradient, preset phase gradient, etc. corresponding to the target acquisition sequence that rotate at a specific angle as the number of excitations increases during excitation sampling.

[0045] Step S120 , decomposing each gradient vector respectively to obtain a diffusion sensitivity factor of each gradient vector on each axis of the stationary coordinate system of the target acquisition sequence.

[0046] In this step, each gradient vector, that is, the gradient vector on each axis of the rotating coordinate system of the target acquisition sequence, refers to the gradient vector generated on each axis of the rotating coordinate system of the target acquisition sequence corresponding to the current excitation in the case of non-first excitation sampling; the target acquisition sequence refers to an acquisition sequence for acquiring magnetic resonance signals generated by macroscopic magnetization vectors in a magnetic resonance system; the stationary coordinate system of the target acquisition sequence refers to a stationary coordinate system for obtaining the gradient vector corresponding to the first excitation in the case of the first excitation; the diffusion sensitivity factor, also known as the b-value or b-value, is both an important working parameter obtained based on the sequence waveform of the magnetic resonance acquisition sequence and an important reference indicator for measuring the diffusion ability of the magnetic resonance acquisition sequence for water molecules; the diffusion sensitivity factor on each axis of the stationary coordinate system, that is, the diffusion sensitivity factor on each axis of the stationary coordinate system of the target acquisition sequence, refers to the diffusion sensitivity factor corresponding to each gradient vector on each axis of the stationary coordinate system of the target acquisition sequence obtained by decomposing each gradient vector separately.

[0047] Specifically, the specific method of decomposing each gradient vector separately may be to perform vector decomposition processing on the gradient vector generated on each axis of the rotating coordinate system of the target acquisition sequence separately; the specific position of the stationary coordinate system of the target acquisition sequence may be relatively set based on the position of the region of interest scanned and imaged by the magnetic resonance system.

[0048] In practical applications, a specific method of decomposing each gradient vector to obtain the diffusion sensitivity factor of each gradient vector on each axis of the stationary coordinate system of the target acquisition sequence may be to perform vector decomposition processing on the gradient vector on each axis of the rotating coordinate system to obtain a number of mapping vectors of each gradient vector on each axis of the stationary coordinate system, and then obtain the diffusion sensitivity factor corresponding to each axis of the stationary coordinate system of the target acquisition sequence according to each mapping vector.

[0049] Step S130 , summing up the diffusion sensitivity factors on each axis of the stationary coordinate system to obtain the diffusion sensitivity factor corresponding to the current excitation.

[0050] In this step, the diffusion sensitivity factor on each axis of the stationary coordinate system, that is, the diffusion sensitivity factor on each axis of the stationary coordinate system of the target acquisition sequence, refers to the diffusion sensitivity factor corresponding to each gradient vector on each axis of the stationary coordinate system of the target acquisition sequence obtained by decomposing each gradient vector respectively; the diffusion sensitivity factor corresponding to the current excitation refers to the diffusion sensitivity factor corresponding to the current excitation obtained by summing the diffusion sensitivity factors on each axis of the stationary coordinate system.

[0051] Specifically, by summing the diffusion sensitivity factors on each axis of the stationary coordinate system to obtain the diffusion sensitivity factor corresponding to the current excitation, it is possible to solve the problem that a wavelet in the sequence waveform of the non-Cartesian acquisition sequence will rotate at a specific angle as the number of excitations increases, thereby making it difficult to accurately calculate the diffusion sensitivity factor of the sequence. Accurately calculating the diffusion sensitivity factor of the sequence not only helps to analyze the cause of signal attenuation of non-diffusion-weighted sequences to optimize the design mechanism of non-diffusion-weighted sequences, but also helps to improve the imaging quality of diffusion-weighted sequences, thereby effectively improving the diagnostic accuracy based on reconstructed images.

[0052] In practical applications, the specific implementation process of the above steps S110 to S130 can be as follows Figure 2 The form shown, that is, the specific implementation process of the above steps S110 to S130, can be specifically implemented through the following steps:

[0053] First, in the case of non-first excitation sampling, obtain the gradient vector R on the RO' axis of the rotating coordinate system of the target acquisition sequence corresponding to the current excitation, the gradient vector P on the PE' axis of the rotating coordinate system, and the gradient vector S on the SS' axis of the rotating coordinate system.

[0054] Then, the gradient vector R, the gradient vector P, and the gradient vector S are respectively decomposed to obtain the mapping gradient vector of the gradient vector R on the RO axis of the stationary coordinate system, the PE axis of the stationary coordinate system, and the SS axis of the stationary coordinate system, the mapping gradient vector of the gradient vector P on the RO axis of the stationary coordinate system, the PE axis of the stationary coordinate system, and the SS axis of the stationary coordinate system, and the mapping gradient vector of the gradient vector S on the RO axis of the stationary coordinate system, the PE axis of the stationary coordinate system, and the SS axis of the stationary coordinate system.

[0055] Next, the mapping gradient vectors corresponding to the gradient vector R are summed to obtain the mapping vector sum R' corresponding to the gradient vector R; the mapping gradient vectors corresponding to the gradient vector P are summed to obtain the mapping vector sum P' corresponding to the gradient vector P; the mapping gradient vectors corresponding to the gradient vector S are summed to obtain the mapping vector sum S' corresponding to the gradient vector S.

[0056] Afterwards, based on the mapping vector and R', the mapping vector and P', and the mapping vector and S', the diffusion sensitivity factor b1 corresponding to the RO axis of the stationary coordinate system, the diffusion sensitivity factor b2 corresponding to the PE axis of the stationary coordinate system, and the diffusion sensitivity factor b3 corresponding to the SS axis of the stationary coordinate system are obtained.

[0057] Finally, the diffusion sensitivity factor b corresponding to the current excitation is obtained by summing the diffusion sensitivity factor b1 corresponding to the RO axis of the stationary coordinate system, the diffusion sensitivity factor b2 corresponding to the PE axis of the stationary coordinate system, and the diffusion sensitivity factor b3 corresponding to the SS axis of the stationary coordinate system.

[0058] The above-mentioned method for acquiring the diffusion sensitivity factor of the target acquisition sequence, first, in the case of non-first excitation sampling, obtains the gradient vector on each axis of the rotating coordinate system of the target acquisition sequence corresponding to the current excitation. Then, each gradient vector is decomposed and processed respectively to obtain the diffusion sensitivity factor of each gradient vector on each axis of the stationary coordinate system of the target acquisition sequence. Finally, the diffusion sensitivity factor on each axis of the stationary coordinate system is summed to obtain the diffusion sensitivity factor corresponding to the current excitation. The present application decomposes the gradient vector on each axis of the rotating coordinate system of the target acquisition sequence corresponding to the current excitation into mapping vectors on each axis of the stationary coordinate system of the target acquisition sequence, obtains the diffusion sensitivity factor corresponding to each axis of the stationary coordinate system of the target acquisition sequence based on the sum of the mapping vectors corresponding to each axis of the stationary coordinate system, and obtains the diffusion sensitivity factor corresponding to the current excitation by summing the diffusion sensitivity factors corresponding to each axis of the stationary coordinate system of the target acquisition sequence, which can not only improve the data accuracy of the diffusion sensitivity factor of the non-Cartesian acquisition sequence obtained, but also effectively improve the imaging quality of the non-Cartesian acquisition sequence.

[0059] Regarding the specific method of obtaining the diffusion sensitivity factor on each axis of the stationary coordinate system according to the mapping vector, in one embodiment, the target acquisition sequence is a non-Cartesian acquisition sequence; Figure 3 As shown, the above step S120 specifically includes:

[0060] Step S310 , based on the parallelogram rule, respectively obtain a first mapping vector, a second mapping vector, and a third mapping vector of each gradient vector in the stationary coordinate system.

[0061] In this step, each gradient vector, that is, the gradient vector on each axis of the rotating coordinate system of the target acquisition sequence, refers to the gradient vector generated on each axis of the rotating coordinate system of the target acquisition sequence corresponding to the current excitation in the case of non-first excitation sampling; the stationary coordinate system, that is, the stationary coordinate system of the target acquisition sequence, refers to the stationary coordinate system used to obtain the gradient vector corresponding to the first excitation in the case of the first excitation, and the specific position of the stationary coordinate system can be relatively set based on the position of the region of interest scanned and imaged by the magnetic resonance system; the first mapping vector, the second mapping vector, and the third mapping vector of each gradient vector in the stationary coordinate system refer to the gradient vectors generated on each axis of the rotating coordinate system of the target acquisition sequence, which are respectively obtained based on the parallelogram law, and the corresponding first mapping vector, second mapping vector, and third mapping vector in the stationary coordinate system.

[0062] Specifically, the quantitative correspondence between the gradient vectors generated on each axis of the rotating coordinate system of the target acquisition sequence and the first mapping vector, the second mapping vector, and the third mapping vector can be a one-to-three relationship, that is, one gradient vector on each axis of the rotating coordinate system of the target acquisition sequence can correspond to three mapping vectors in the stationary coordinate system of the target acquisition sequence (that is, the first mapping vector, the second mapping vector, and the third mapping vector).

[0063] In practical applications, based on the parallelogram rule, a specific implementation method for obtaining a first mapping vector, a second mapping vector, and a third mapping vector of a certain gradient vector in a stationary coordinate system may be as follows: Figure 4 The form shown, that is, the specific implementation process of the above step S310, can be specifically implemented by performing the following operations:

[0064] Assume that it is known that at each excitation, the rotating coordinate system of the target acquisition sequence will rotate around the SS axis of the stationary coordinate system at a specific angle, so that the SS' axis in the rotating coordinate system of the target acquisition sequence coincides with the SS axis of the stationary coordinate system (that is, the gradient vector on the SS' axis in the rotating coordinate system does not change when it is mapped to the SS axis of the stationary coordinate system). The gradient on the SS axis of the stationary coordinate system is the gradient G SS (i.e., the gradient vector G' PE The corresponding third mapping vector) is then the gradient vector G' on the PE' axis in the rotating coordinate system of the target acquisition sequence. PE When the gradient vector G' on the PE' axis in the rotating coordinate system is PE , decomposed into the gradient G on the PE axis of the stationary coordinate system PE (i.e., the gradient vector G' PEThe corresponding first mapping vector) and the gradient G on the stationary coordinate system RO axis RO (i.e., the gradient vector G' PE The corresponding second mapping vector).

[0065] Step S320: Obtain the dispersion sensitivity factor on each axis of the stationary coordinate system according to each first mapping vector, each second mapping vector, and each third mapping vector.

[0066] In this step, each first mapping vector, each second mapping vector, and each third mapping vector, that is, the first mapping vector, the second mapping vector, and the third mapping vector corresponding to each gradient vector in the stationary coordinate system, refer to the gradient vectors respectively generated on each axis of the rotating coordinate system of the target acquisition sequence obtained based on the parallelogram law, and the corresponding first mapping vector, the second mapping vector, and the third mapping vector in the stationary coordinate system; the diffusion sensitivity factor on each axis of the stationary coordinate system refers to the diffusion sensitivity factor corresponding to each axis of the stationary coordinate system obtained according to each first mapping vector, each second mapping vector, and each third mapping vector on each axis of the stationary coordinate system.

[0067] The embodiment of the present application obtains the first mapping vector, the second mapping vector, and the third mapping vector of each gradient vector in the stationary coordinate system based on the parallelogram rule, and obtains the diffusion sensitivity factor on each axis of the stationary coordinate system according to each first mapping vector, each second mapping vector, and each third mapping vector, thereby effectively ensuring the data accuracy of the diffusion sensitivity factor of the non-Cartesian acquisition sequence.

[0068] Regarding the specific method of obtaining the dispersion sensitivity factor on each axis of the stationary coordinate system, in one embodiment, as follows: Figure 5 As shown, the above step S320 specifically includes:

[0069] In step S510, each first mapping vector, each second mapping vector, and each third mapping vector are summed up to obtain the gradient vector sum on each axis of the stationary coordinate system.

[0070] In this step, each first mapping vector, each second mapping vector, and each third mapping vector, that is, the first mapping vector, the second mapping vector, and the third mapping vector corresponding to each gradient vector in the stationary coordinate system, refer to the gradient vectors respectively generated on each axis of the rotating coordinate system of the target acquisition sequence based on the parallelogram law, and the corresponding first mapping vector, second mapping vector, and third mapping vector in the stationary coordinate system; the stationary coordinate system, that is, the stationary coordinate system of the target acquisition sequence, refers to the stationary coordinate system used to obtain the gradient vector corresponding to the first excitation in the case of the first excitation, and the specific position of the stationary coordinate system can be relatively set based on the position of the region of interest scanned by the magnetic resonance system; the sum of the gradient vectors on each axis of the stationary coordinate system refers to the sum of the gradient vectors corresponding to each axis of the stationary coordinate system obtained by summing the first mapping vector, the second mapping vector, and the third mapping vector corresponding to each axis of the stationary coordinate system.

[0071] In practical applications, the specific method of summing up the first mapping vectors, the second mapping vectors, and the third mapping vectors to obtain the gradient vector sum on each axis of the stationary coordinate system may be to sum up the first mapping vectors, the second mapping vectors, and the third mapping vectors corresponding to each axis of the stationary coordinate system to obtain the gradient vector sum corresponding to each axis of the stationary coordinate system.

[0072] Step S520: Obtain the diffusion sensitivity factor on each axis of the stationary coordinate system based on the sum of each gradient vector.

[0073] In this step, the gradient vector sums, that is, the gradient vector sums on each axis of the stationary coordinate system, refer to the gradient vector sums corresponding to each axis of the stationary coordinate system obtained by summing the first mapping vector, the second mapping vector, and the third mapping vector corresponding to each axis of the stationary coordinate system respectively; the diffusion sensitivity factors on each axis of the stationary coordinate system refer to the diffusion sensitivity factors corresponding to each axis of the stationary coordinate system obtained based on the gradient vector sums corresponding to each axis of the stationary coordinate system.

[0074] In the embodiment of the present application, the first mapping vectors, the second mapping vectors, and the third mapping vectors are summed to obtain the gradient vector sums on each axis of the stationary coordinate system, and the diffusion sensitivity factors on each axis of the stationary coordinate system are obtained based on the gradient vector sums. In this way, the diffusion sensitivity factor generated by the rotation gradient is incorporated into the overall calculation process of the diffusion sensitivity factor corresponding to the non-Cartesian sequence, thereby effectively improving the data accuracy of the obtained diffusion sensitivity factor of the non-Cartesian acquisition sequence.

[0075] Regarding the specific method of calculating the dispersion sensitivity factor on each axis of the stationary coordinate system, in one embodiment, as follows: Figure 6 As shown, the above step S520 specifically includes:

[0076] Step S610: determining the gradient amplitude of the current gradient application time period based on the sum of each gradient vector.

[0077] In this step, the gradient vector sum, that is, the gradient vector sum on each axis of the stationary coordinate system, refers to the gradient vector sum corresponding to each axis of the stationary coordinate system obtained by summing the first mapping vector, the second mapping vector, and the third mapping vector corresponding to each axis of the stationary coordinate system respectively; the gradient amplitude in the current gradient application time period refers to the gradient amplitude corresponding to each axis in the stationary coordinate system in the current gradient application time period determined based on the gradient vector sum corresponding to each axis in the stationary coordinate system.

[0078] Step S620, obtaining the duration of the current gradient application time period, the gyromagnetic ratio, and the gradient interval between the bipolar gradients corresponding to the current excitation.

[0079] In this step, the gradient amplitude of the current gradient application time period refers to the gradient amplitude corresponding to each axis in the stationary coordinate system in the current gradient application time period determined based on the gradient vector sum corresponding to each axis in the stationary coordinate system; the gradient interval between the bipolar gradients corresponding to the current excitation refers to the gradient interval between the bipolar gradients applied by the current excitation in the current gradient application time period.

[0080] Step S630: Obtain the diffusion sensitivity factor on each axis of the stationary coordinate system according to each gradient amplitude, duration, gyromagnetic ratio, and gradient interval.

[0081] In this step, each gradient amplitude, i.e., the gradient amplitude of the current gradient application time period, refers to the gradient amplitude corresponding to each axis in the stationary coordinate system in the current gradient application time period determined based on the gradient vector sum corresponding to each axis in the stationary coordinate system; the duration, i.e., the duration of the current gradient application time period; the gradient interval, i.e., the gradient interval between the bipolar gradients corresponding to the current excitation; the stationary coordinate system, i.e., the stationary coordinate system of the target acquisition sequence, refers to the stationary coordinate system used to obtain the initial gradient vector corresponding to the first excitation in the case of the first excitation, and the specific position of the stationary coordinate system can be relatively set based on the position of the region of interest scanned and imaged by the magnetic resonance system; the diffusion sensitivity factor on each axis of the stationary coordinate system refers to the diffusion sensitivity factor corresponding to each axis of the stationary coordinate system calculated according to the gradient amplitude corresponding to each axis in the stationary coordinate system in the current gradient application time period, the duration of the current gradient application time period, and the gradient interval between the bipolar gradients corresponding to the current excitation.

[0082] In practical applications, the above step S630 can be specifically implemented in the form shown in the following formula (that is, the following formula can be used to calculate the dispersion sensitivity factor corresponding to each axis of the stationary coordinate system):

[0083] b=G 2 γ 2 δ 2 (Δ-δ / 3)

[0084] Among them, G is the gradient amplitude of the current gradient application time period; b is the diffusion sensitivity factor corresponding to a certain axis of the stationary coordinate system of the target acquisition sequence; δ is the duration of the current gradient application time period; γ is the gyromagnetic ratio; Δ is the gradient interval between the bipolar gradients corresponding to the current excitation.

[0085] The embodiment of the present application determines the gradient amplitude of the current gradient application time period based on the sum of each gradient vector, and obtains the diffusion sensitivity factor on each axis of the stationary coordinate system according to each gradient amplitude, the duration of the current gradient application time period, the gyromagnetic ratio, and the gradient interval between the bipolar gradients corresponding to the current excitation, thereby effectively improving the data accuracy of the obtained diffusion sensitivity factor of the non-Cartesian acquisition sequence, thereby ensuring the imaging quality of the non-Cartesian acquisition sequence.

[0086] Regarding the specific method of obtaining the initial diffusion sensitivity factor corresponding to the first excitation, in one embodiment, the position of the above-mentioned stationary coordinate system is relatively set based on the position of the region of interest of the scanning imaging; Figure 7 As shown, the above method also includes:

[0087] Step S710 , in the case of first shot sampling, obtaining initial gradient vectors corresponding to the first shot on each axis of the stationary coordinate system of the target acquisition sequence.

[0088] In this step, excitation sampling refers to the signal acquisition process of exciting the macroscopic magnetization vector in the magnetic resonance system by using an excitation radio frequency pulse so that the macroscopic magnetization vector precesses around the magnetic field direction, and acquiring the magnetic resonance signal generated by the macroscopic magnetization vector by using a target acquisition sequence; first excitation sampling refers to the first execution of the aforementioned signal acquisition process in the magnetic resonance system; the stationary coordinate system of the target acquisition sequence refers to the stationary coordinate system used to obtain the initial gradient vector corresponding to the first excitation in the case of the first excitation, and the specific position of the stationary coordinate system can be relatively set based on the position of the region of interest scanned by the magnetic resonance system; the initial gradient vector on each axis refers to the initial gradient vector generated on each axis of the stationary coordinate system of the target acquisition sequence corresponding to the first excitation in the case of the first excitation sampling.

[0089] Step S720: summing up the initial gradient vectors to obtain an initial diffusion sensitivity factor corresponding to the first excitation.

[0090] In this step, each initial gradient vector, that is, the initial gradient vector on each axis, refers to the initial gradient vector generated on each axis of the stationary coordinate system of the target acquisition sequence corresponding to the first excitation in the case of the first excitation sampling; the initial diffusion sensitivity factor corresponding to the first excitation refers to the initial gradient vector sum obtained by summing the initial gradient vectors generated on each axis of the stationary coordinate system, and the initial diffusion sensitivity factor corresponding to the first excitation is calculated based on the initial gradient vector sum.

[0091] In the embodiment of the present application, in the case of first excitation sampling, initial gradient vectors on each axis of the stationary coordinate system of the target acquisition sequence corresponding to the first excitation are obtained, and each initial gradient vector is summed to obtain the initial diffusion sensitivity factor corresponding to the first excitation, thereby effectively ensuring the data accuracy of the initial diffusion sensitivity factor corresponding to the first excitation.

[0092] Regarding the specific manner of determining the current rotation angle of the rotating coordinate system, in one embodiment, the method further includes:

[0093] In the case where it is not the first excitation sampling and the target acquisition sequence is a propeller sequence, the current rotation angle of the rotating coordinate system is determined based on the preset angle and the number of excitations corresponding to the target acquisition sequence.

[0094] Among them, excitation sampling refers to the signal acquisition process of using excitation radio frequency pulses to excite the macroscopic magnetization vector in the magnetic resonance system, so that the macroscopic magnetization vector precesses around the magnetic field direction, and using the target acquisition sequence to acquire the magnetic resonance signal generated by the macroscopic magnetization vector; non-first excitation sampling refers to the fact that the aforementioned signal acquisition process is not performed for the first time in the magnetic resonance system; the number of excitations corresponding to the target acquisition sequence can be the total number of excitations that are pre-set by the user and require the target acquisition sequence for excitation sampling; the rotating coordinate system, that is, the rotating coordinate system of the target acquisition sequence, refers to the rotating coordinate system used to obtain the gradient vector corresponding to the current excitation in the case of non-first excitation sampling; the current rotation angle of the rotating coordinate system refers to the current rotation angle of the rotating coordinate system of the target acquisition sequence determined based on the preset angle and the number of excitations corresponding to the target acquisition sequence in the case of non-first excitation sampling and the target acquisition sequence is a propeller sequence.

[0095] Specifically, the propeller sequence, that is, the signal acquisition sequence generated based on the propeller technology (Propoller), is a signal acquisition sequence that realizes the magnetic resonance signal acquisition process based on the interaction between the K-space radial filling technology and the fast spin echo sequence (i.e., FSE sequence) or the fast inversion recovery sequence (i.e., FIR sequence).

[0096] In practical applications, assuming that the preset angle is known to be 180° and the number of excitations corresponding to the target acquisition sequence is set to N, based on the preset angle 180° and the number of excitations N corresponding to the target acquisition sequence, the current rotation angle of the rotating coordinate system can be determined to be 180° / N.

[0097] The embodiment of the present application determines the current rotation angle of the rotating coordinate system based on a preset angle and the number of excitations corresponding to the target acquisition sequence when it is not the first excitation sampling and the target acquisition sequence is a propeller sequence, thereby ensuring the data accuracy of the diffusion sensitivity factor generated by the rotation steps of the propeller acquisition sequence obtained subsequently, thereby effectively improving the imaging quality of the non-Cartesian acquisition sequence.

[0098] 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.

[0099] Based on the same inventive concept, the embodiment of the present application also provides a device for acquiring a diffusion sensitive factor of a target acquisition sequence for implementing the method for acquiring a diffusion sensitive factor of a target acquisition sequence 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 the embodiments of the device for acquiring a diffusion sensitive factor of one or more target acquisition sequences provided below can refer to the limitations of the method for acquiring a diffusion sensitive factor of a target acquisition sequence above, and will not be repeated here.

[0100] In one embodiment, Figure 8 As shown, a device for acquiring a diffusion sensitivity factor of a target acquisition sequence is provided, the device comprising:

[0101] The module 810 for acquiring the gradient vector of each axis is used to acquire the gradient vector of each axis of the rotating coordinate system of the target acquisition sequence corresponding to the current excitation when the sampling is not the first excitation.

[0102] The module 820 for acquiring the diffusion sensitivity factor of each axis is used to decompose each of the gradient vectors to obtain the diffusion sensitivity factor of each of the gradient vectors on each axis of the stationary coordinate system of the target acquisition sequence;

[0103] The sequential diffusion sensitivity factor output module 830 is used to sum the diffusion sensitivity factors on each axis of the stationary coordinate system to obtain the diffusion sensitivity factor corresponding to the current excitation.

[0104] In one embodiment, the target acquisition sequence is a non-Cartesian acquisition sequence; the module 820 for acquiring the diffusion sensitivity factor of each axis is specifically used to acquire the first mapping vector, the second mapping vector, and the third mapping vector of each gradient vector in the stationary coordinate system based on the parallelogram rule; and acquire the diffusion sensitivity factor on each axis of the stationary coordinate system according to each of the first mapping vectors, each of the second mapping vectors, and each of the third mapping vectors.

[0105] In one embodiment, the module 820 for acquiring the diffusion sensitivity factor of each axis is further used to sum each of the first mapping vectors, each of the second mapping vectors, and each of the third mapping vectors to obtain the gradient vector sum on each axis of the stationary coordinate system; and based on each of the gradient vector sums, obtain the diffusion sensitivity factor on each axis of the stationary coordinate system.

[0106] In one embodiment, the module 820 for acquiring the diffusion sensitivity factor of each axis is further used to determine the gradient amplitude of the current gradient application time period based on the sum of each gradient vector; obtain the duration of the current gradient application time period, the gyromagnetic ratio, and the gradient interval between the bipolar gradients corresponding to the current excitation; and obtain the diffusion sensitivity factor on each axis of the stationary coordinate system according to each gradient amplitude, the duration, the gyromagnetic ratio, and the gradient interval.

[0107] In one of the embodiments, the position of the stationary coordinate system is relatively set based on the position of the region of interest of the scanning imaging; the above-mentioned device also includes: an initial diffusion sensitivity factor acquisition module, which is used to obtain the initial gradient vectors on each axis of the stationary coordinate system of the target acquisition sequence corresponding to the first excitation in the case of the first excitation sampling; and each of the initial gradient vectors is summed to obtain the initial diffusion sensitivity factor corresponding to the first excitation.

[0108] In one of the embodiments, the above-mentioned device also includes: a current rotation angle acquisition module, which is used to determine the current rotation angle of the rotating coordinate system based on a preset angle and the number of excitations corresponding to the target acquisition sequence when the sampling is not the first excitation and the target acquisition sequence is a propeller sequence.

[0109] Each module in the above-mentioned device for acquiring the diffusion sensitivity factor of the target acquisition sequence can be implemented in whole or in part by software, hardware, or a combination thereof. Each of the above-mentioned modules 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 the operations corresponding to each of the above modules.

[0110] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Fig. 9 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 data such as data related to the calculation of the diffusion sensitivity factor of the target acquisition sequence. 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 method for obtaining the diffusion sensitivity factor of a target acquisition sequence is implemented.

[0111] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Fig.10As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device 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 and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for acquiring a diffusion sensitivity factor of a target acquisition sequence is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse, etc.

[0112] Those skilled in the art will understand that Fig. 9 or Fig.10 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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 obtaining a diffusion sensitivity factor of a target acquisition sequence, characterized in that: The method comprises: In the case of non-first excitation sampling, the gradient vector corresponding to the current excitation on each axis of the rotating coordinate system of the target acquisition sequence is obtained; Decomposing each of the gradient vectors respectively to obtain a diffusion sensitivity factor of each of the gradient vectors on each axis of the stationary coordinate system of the target acquisition sequence; The diffusion sensitivity factors on each axis of the stationary coordinate system are summed to obtain the diffusion sensitivity factor corresponding to the current excitation.

2. The method according to claim 1, characterized in that The target acquisition sequence is a non-Cartesian acquisition sequence; The step of respectively decomposing each of the gradient vectors to obtain a diffusion sensitivity factor of each of the second gradient vectors on each axis of the stationary coordinate system of the target acquisition sequence includes: Based on the parallelogram rule, respectively obtain a first mapping vector, a second mapping vector, and a third mapping vector of each of the gradient vectors in the stationary coordinate system; A dispersion sensitivity factor on each axis of the stationary coordinate system is obtained according to each of the first mapping vectors, each of the second mapping vectors, and each of the third mapping vectors.

3. The method according to claim 2, characterized in that The acquiring the dispersion sensitivity factor on each axis of the stationary coordinate system according to each of the first mapping vectors, each of the second mapping vectors, and each of the third mapping vectors includes: respectively summing up the first mapping vectors, the second mapping vectors, and the third mapping vectors to obtain a gradient vector sum on each axis of the stationary coordinate system; Based on the sum of the gradient vectors, a diffusion sensitivity factor on each axis of the stationary coordinate system is obtained.

4. The method according to claim 3, characterized in that The obtaining, based on the sum of the gradient vectors, the diffusion sensitivity factor on each axis of the stationary coordinate system comprises: Determining the gradient amplitude of the current gradient application time period based on each of the gradient vector sums; Acquire the duration of the current gradient application time period, the gyromagnetic ratio, and the gradient interval between the bipolar gradients corresponding to the current excitation; The diffusion sensitivity factor on each axis of the stationary coordinate system is obtained according to each of the gradient amplitudes, the duration, the gyromagnetic ratio, and the gradient interval.

5. The method according to any one of claims 1 to 4, characterized in that The position of the stationary coordinate system is relatively set based on the position of the region of interest of the scanned imaging; The method further comprises: In the case of first-shot sampling, obtaining initial gradient vectors corresponding to the first shot on each axis of the stationary coordinate system of the target acquisition sequence; The initial gradient vectors are summed to obtain an initial diffusion sensitivity factor corresponding to the first excitation.

6. The method according to claim 1, characterized in that The method further comprises: In the case of the non-first excitation sampling and the target acquisition sequence being a propeller sequence, the current rotation angle of the rotating coordinate system is determined based on a preset angle and the number of excitations corresponding to the target acquisition sequence.

7. A device for acquiring a diffusion sensitivity factor of a target acquisition sequence, characterized in that: The device comprises: A module for acquiring gradient vectors of each axis, used for acquiring the gradient vectors of each axis of the rotating coordinate system of the target acquisition sequence corresponding to the current excitation in the case of non-first excitation sampling; A diffusion sensitivity factor acquisition module for each axis is used to decompose each of the gradient vectors to obtain a diffusion sensitivity factor of each of the gradient vectors on each axis of the stationary coordinate system of the target acquisition sequence; The sequential diffusion sensitivity factor output module is used to sum the diffusion sensitivity factors on each axis of the stationary coordinate system to obtain the diffusion sensitivity factor corresponding to the current excitation.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

Images