Method, apparatus, computing device and medium for generating echo time-dependent magnetic resonance diffusion imaging signals

Abstract

The present invention provides a method and apparatus for generating an echo time-dependent magnetic resonance diffusion imaging signal, which includes the steps of acquiring a magnetic resonance non-diffusion-weighted image and a magnetic resonance multi-b-value diffusion-weighted image, calculating a magnetic resonance diffusion signal without T2 value weighting corresponding to various water components in the human tissue for each voxel using the magnetic resonance non-diffusion-weighted image and quantitative T2 values ​​of various water components in the human tissue, calculating a diffusion coefficient corresponding to various water components in the human tissue for each voxel using the magnetic resonance multi-b-value diffusion-weighted image, the magnetic resonance diffusion signal, and the quantitative T2 values, and calculating a magnetic resonance diffusion imaging signal acquired using an arbitrary echo time for each voxel using the magnetic resonance multi-b-value diffusion-weighted image, the magnetic resonance diffusion signal, the quantitative T2 values, and the diffusion coefficients.

Description

[Technical Field]

[0001] <Cross-reference to related patent applications> This application claims priority to a Chinese patent application filed on November 15, 2023, bearing application number 202311521346.1 and entitled "Method and apparatus for generating echo time-dependent magnetic resonance diffusion imaging signals," the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to the field of medical image imaging and processing, and more particularly to a method, apparatus, computing device and medium for generating echo time-dependent magnetic resonance diffusion imaging signals. [Background technology]

[0003] Magnetic resonance imaging (MRI) is a noninvasive in vivo medical imaging method widely used in clinical medicine and medical research. The principle of MRI is that hydrogen atoms are excited by fixed-frequency RF pulses in a constant magnetic field, generating a magnetic moment. The magnetization intensity gradually weakens according to a constant T1 (longitudinal relaxation time) and T2 (transverse relaxation time). At a certain echo time (TE), magnetic resonance signals are acquired and imaged. Diffusion MRI, also known as diffusion imaging, is a type of MRI that applies a pair of diffusion gradients within the echo time to capture the directional characteristics of the diffusive motion of water molecules in a cellular environment. This allows the structure of the microenvironment in which water molecules reside to be measured. Diffusion imaging measurements are widely used in analyzing the structure of the human nervous system and diagnosing diseases in body parts such as the brain and kidneys.

[0004] Diffusion imaging can measure the microstructural characteristics of the cellular environment after post-processing of diffusion signals collected from human tissue using a specific diffusion sequence. Clinical magnetic resonance imaging typically uses a spin-echo-based planar echo imaging sequence to acquire images. By adjusting many parameters within the sequence, such as the echo time, diffusion b-value, and diffusion gradient direction, the desired diffusion-weighted image can be obtained. In the acquired image, the brightness of a single pixel represents the signal within a rectangular voxel. Because the size of a single voxel is typically hundreds or thousands of times larger than a human cell, the signal at each point in the diffusion image represents the sum of the signals from all water molecules within the voxel. To measure the microstructure of the cellular environment where water molecules reside, post-processing modeling of the diffusion signal is required using a corresponding diffusion model. Currently, models such as diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), and neurite orientation dispersion and density imaging (NODDI) are available. In this way, quantitative model parameters such as mean diffusion coefficient, anisotropy fraction, neurite fraction, free water fraction and directional dispersion are obtained, which describe various features of the microenvironment. Summary of the Invention [Problem to be solved by the invention]

[0005] In these diffusion models, the T2 of all water molecules within a single voxel is considered to be a uniform value. However, the calculated model parameters are dependent on the TE. When imaging with different MRI systems and acquisition strategies, measurement deviations may occur in the resulting parameters after acquisition processing at different TEs. The main reason for this is that the T2 of water molecules in different cellular environments varies, leading to the contribution of various components to the total signal varying with TE. Generally, water molecules in the cellular environment of human tissues are divided into intracellular water molecules, extracellular water molecules, and free water molecules, and these three components are distributed in different proportions in different tissues. Some studies have shown that because the T2 of these three components differs, the ratio of the three components in the signal acquired using a specific TE varies depending on the TE and their respective T2 ratios. [Means for solving the problem]

[0006] Each embodiment of the present invention provides a method, apparatus, computing device, and medium for generating an echo time-dependent magnetic resonance diffusion imaging signal.

[0007] In a first aspect, the present invention provides a method for generating an echo time dependent magnetic resonance diffusion imaging signal, the method comprising: acquiring magnetic resonance non-diffusion weighted images acquired using multiple echo times and magnetic resonance multi-b-value diffusion weighted images acquired using a single echo time; calculating a magnetic resonance diffusion signal for each voxel that does not have a weighting factor for the transverse relaxation time values ​​corresponding to the various water components in the human tissue, based on the magnetic resonance non-diffusion weighted image and the transverse relaxation time values ​​of the various water components in the human tissue; calculating diffusion coefficients corresponding to various water components in the human tissue for each voxel according to the magnetic resonance multi-b-value diffusion weighted image, the magnetic resonance diffusion signal, and the transverse relaxation time value; and calculating for each voxel a magnetic resonance diffusion imaging signal collected using any echo time using the magnetic resonance multi-b-value diffusion weighted image, the magnetic resonance diffusion signal, the transverse relaxation time value, and the diffusion coefficient to generate the magnetic resonance diffusion imaging signal.

[0008] When acquiring the magnetic resonance non-diffusion-weighted image and the magnetic resonance multi-b-value diffusion-weighted image, the same magnetic resonance diffusion imaging sequence is used, and except for two magnetic resonance sequence parameters, echo time or diffusion b-value, which are set to multiple values ​​within a certain range, the remaining magnetic resonance sequence parameters are set to the same, whereby when acquiring the magnetic resonance non-diffusion-weighted image, the diffusion b-value is set to zero and the echo time is set to at least two, and when acquiring the magnetic resonance multi-b-value diffusion-weighted image, the echo time is set to a single fixed value and the diffusion b-value is set to at least two.

[0009] The various water components in the human tissues are classified into two categories: one category is where two water components exist in the human tissues, including intracellular water and extracellular water, and the other category is where three water components exist in the human tissues, including intracellular water, extracellular water, and free water.

[0010] When the various water components in the human tissue include intracellular water and extracellular water, the unweighted magnetic resonance diffusion signal of the transverse relaxation time value is calculated for each voxel using the following equation (1): JPEG0007807574000001.jpg7170 When the various water components in the human tissue include intracellular water, extracellular water, and free water, the magnetic resonance diffusion signal without weighting of the transverse relaxation time value is calculated for each voxel using the following equation (2): JPEG0007807574000002.jpg8170JPEG0007807574000003.jpg22170

[0011] When the various water components in the human tissue include intracellular water and extracellular water, the diffusion coefficients corresponding to the various water components in the human tissue are calculated for each voxel using the following equation (3): JPEG0007807574000004.jpg7170 When the various water components in the human tissue include intracellular water, extracellular water, and free water, the diffusion coefficients corresponding to the various water components in the human tissue are calculated for each voxel using the following equation (4): JPEG0007807574000005.jpg14170JPEG0007807574000006.jpg28170

[0012] When calculating the diffusion coefficient, a single fitting calculation is performed in the vector direction of each diffusion-weighted gradient for the signal of the magnetic resonance multi-b-value diffusion-weighted image used.

[0013] When the various water components in the human tissue include intracellular water and extracellular water, the magnetic resonance diffusion imaging signal collected using any echo time is calculated for each voxel using the following equation (5), to generate: JPEG0007807574000007.jpg33170(5) When the various water components in the human tissue include intracellular water, extracellular water, and free water, the magnetic resonance diffusion imaging signal collected using an arbitrary echo time is calculated for each voxel using the following equation (6), to generate: JPEG0007807574000008.jpg49170(6) JPEG0007807574000009.jpg38170

[0014] In a second aspect, the present invention provides an apparatus for generating an echo time-dependent magnetic resonance diffusion imaging signal, which includes an image acquisition module, a multi-component diffusion signal calculation module, a multi-component diffusion coefficient calculation module, and a diffusion imaging signal generation module. The image acquisition module is used to acquire magnetic resonance non-diffusion weighted images acquired using multiple echo times and magnetic resonance multi-b-value diffusion weighted images acquired using a single echo time. The multi-component diffusion signal calculation module is used to calculate, for each voxel, a magnetic resonance diffusion signal that does not weight the transverse relaxation time values ​​corresponding to various water components in the human tissue, using the magnetic resonance non-diffusion-weighted image and the transverse relaxation time values ​​of various water components in the human tissue. The multi-component diffusion coefficient calculation module is used to calculate diffusion coefficients corresponding to various water components in human tissue for each voxel using the magnetic resonance multi-b-value diffusion weighted image, the magnetic resonance diffusion signal, and the transverse relaxation time value. The diffusion imaging signal generation module is used to calculate and generate, for each voxel, a magnetic resonance diffusion imaging signal collected using any echo time using the magnetic resonance multi-b-value diffusion weighted image, the magnetic resonance diffusion signal, the transverse relaxation time value, and the diffusion coefficient.

[0015] In a third aspect, the present invention provides a computing device, the computing device including a memory and one or more processors, the memory storing executable code, the one or more processors executing the executable code being used to implement the method for generating an echo time-dependent magnetic resonance diffusion imaging signal described above.

[0016] In a fourth aspect, the present invention provides a computer-readable storage medium having a program stored thereon, the program, when executed by a processor, implementing the above-described method for generating echo time-dependent magnetic resonance diffusion imaging signals.

[0017] Compared with the prior art, the beneficial effects of the present invention are at least as follows:

[0018] In the prior art, the calculation of various diffusion model coefficients is affected by the discrepancy in echo time of sequence parameters, and there is a certain degree of calculation deviation depending on the imaging device and acquisition strategy. In the present invention, a multi-component hypothesis is used to set different relaxation time values ​​and diffusion coefficient values ​​for various types of water molecules in the cellular environment, and the acquired magnetic resonance diffusion-weighted signals are decomposed and reconstructed. The reconstructed signals can completely retain the cellular physiological information of the original signals while eliminating the measurement deviation of the diffusion model coefficients caused by the discrepancy in echo time.

[0019] The present invention generates new signals by reconstructing the original diffusion signals acquired voxel by voxel, and is not limited by the resolution of the diffusion image or the number of diffusion directions. The original diffusion imaging data used in the present invention can also be acquired using diffusion imaging sequences in current clinical magnetic resonance apparatuses and reconstructed using the method of the present invention, making it highly clinically practical.

[0020] In the method for generating diffusion-weighted image signals provided by the present invention, the reconstructed image is identical in size and dimension to the original image, and also has the same diffusion direction and diffusion b-value. Therefore, all diffusion models that can be used to process the original image can also be applied to the reconstructed image, providing flexibility in application.

[0021] The details of one or more embodiments of the invention are set forth in the drawings and description that follow to make other features, objects and advantages of the invention more concise and easy to understand. [Brief explanation of the drawings]

[0022] In order to more clearly describe the technical solutions in the embodiments of the present invention or the related art, the drawings necessary for describing the embodiments or the related art are briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on the disclosed drawings without any creative efforts.

[0023] [Figure 1] 1 is a flowchart of a method for generating an echo time-dependent magnetic resonance diffusion imaging signal according to an embodiment of the present invention. [Figure 2] FIG. 1 illustrates a hypothetical classification of various water components in human tissue according to an embodiment of the present invention. [Figure 3] 1 is an exemplary flowchart of a method for generating a magnetic resonance diffusion imaging signal according to an embodiment of the present invention. [Figure 4] 1 shows the structure of an apparatus for generating an echo time-dependent magnetic resonance diffusion imaging signal according to an embodiment of the present invention; [Figure 5] FIG. 2 illustrates the structure of a computing device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to illustrate the present invention and do not limit the protection scope of the present invention.

[0025] To eliminate the influence of different TEs on the diffusion model coefficients, the inventive concept of the present invention involves performing multi-component decomposition on the collected original diffusion signal, extracting analyzable initial signal components, and reconstructing the diffusion-weighted signal under any matching TE. This prevents deviations in the post-processing calculation of the diffusion model and improves the accuracy of the model coefficient measurement. Specifically, using an assumption based on a multi-component water model of human tissue, the original signal of the magnetic resonance diffusion image is subjected to multi-component decomposition, and then the non-T2-weighted magnetic resonance diffusion signal and the corresponding diffusion coefficients are reconstructed to generate a magnetic resonance diffusion imaging signal collected at any echo time.

[0026] Based on the concept of the present invention, as shown in FIG. 1, the method for generating an echo time-dependent magnetic resonance diffusion imaging signal provided in this embodiment includes the following steps:

[0027] S110: Acquire magnetic resonance non-diffusion weighted images acquired using multiple echo times and magnetic resonance multi-b-value diffusion weighted images acquired using a single echo time.

[0028] In this embodiment, when acquiring a magnetic resonance non-diffusion-weighted image and a magnetic resonance multi-b-value diffusion-weighted image, the same magnetic resonance diffusion imaging sequence is used, and the remaining magnetic resonance sequence parameters are set to the same, except that two magnetic resonance sequence parameters, the echo time or the diffusion b-value, are set to multiple values ​​within a certain range.

[0029] When a single echo time is used to acquire a multi-b-value diffusion-weighted magnetic resonance image, the echo time of the imaging sequence is set to the minimum value that can be adjusted by the magnetic resonance scanner, and the diffusion b-value is set to a value greater than zero but not exceeding the midpoint of the maximum value achievable by the magnetic resonance scanner, for a total of at least two diffusion b-values.

[0030] When multiple echo times are used to acquire non-diffusion-weighted magnetic resonance images, the echo times are set from the minimum value adjustable by the magnetic resonance scanner, and one echo time is set for each increment of a fixed interval value, for a total of at least two echo times. The diffusion b-value is set to zero, and one group of non-diffusion-weighted images is acquired at each echo time, which can be repeatedly acquired.

[0031] S120: Using the non-diffusion-weighted magnetic resonance image and the transverse relaxation time values ​​of various water components in the human tissue, a magnetic resonance diffusion signal that does not perform weighting of the transverse relaxation time values ​​corresponding to various water components in the human tissue is calculated for each voxel.

[0032] In an embodiment, as shown in Figure 2, various assumptions about water components in human tissues are classified into two categories. One category is that there are two water components in human tissues, including intracellular water and extracellular water, and the other category is that there are three water components in human tissues, including intracellular water, extracellular water, and free water. Under these two classification assumptions, the quantitative T2 value, non-T2 weighted magnetic resonance diffusion signal, and diffusion coefficient of each water component are also different.

[0033] When the various water components in human tissues include intracellular water and extracellular water, the unweighted magnetic resonance diffusion signal of the transverse relaxation time value is calculated for each voxel using the following equation (1):

[0034] JPEG0007807574000010.jpg6170

[0035] When the various water components in human tissue include intracellular water, extracellular water, and free water, the unweighted magnetic resonance diffusion signal of the transverse relaxation time value is calculated for each voxel using the following equation (2):

[0036] JPEG0007807574000011.jpg8170

[0037] JPEG0007807574000012.jpg22170

[0038] S130: Calculate the diffusion coefficients corresponding to various water components in human tissue for each voxel according to the magnetic resonance multi-b-value diffusion weighted image, magnetic resonance diffusion signal and transverse relaxation time value.

[0039] In the embodiment, the diffusion coefficients corresponding to various water components in human tissue are calculated based on two assumptions as follows:

[0040] When the various water components in human tissues include intracellular water and extracellular water, the following equation (3) is used to calculate the diffusion coefficients corresponding to the various water components in human tissues for each voxel.

[0041] JPEG0007807574000013.jpg7170

[0042] When the various water components in human tissue include intracellular water, extracellular water, and free water, the following equation (4) is used to calculate the diffusion coefficients corresponding to the various water components in human tissue for each voxel.

[0043] JPEG0007807574000014.jpg14170

[0044] JPEG0007807574000015.jpg28170

[0045] In the embodiment, when calculating the diffusion coefficient, a single fitting calculation is performed in the vector direction of each diffusion-weighted gradient for the signal of the magnetic resonance multi-b-value diffusion-weighted image used.

[0046] S140: A magnetic resonance multi-b-value diffusion weighted image, a magnetic resonance diffusion imaging signal acquired using an arbitrary echo time, is calculated for each voxel by the magnetic resonance diffusion signal, transverse relaxation time value, and diffusion coefficient to generate a magnetic resonance diffusion weighted image.

[0047] In the embodiment, when calculating and generating a magnetic resonance diffusion imaging signal acquired using an arbitrary echo time, the calculation is similarly based on two assumptions, respectively, as described below.

[0048] When the various water components in human tissues include intracellular and extracellular water, the magnetic resonance diffusion imaging signal collected using any echo time is calculated for each voxel using the following equation (5):

[0049] JPEG0007807574000016.jpg33170(5)

[0050] When the various water components in human tissue include intracellular water, extracellular water, and free water, the magnetic resonance diffusion imaging signal acquired using any echo time is calculated for each voxel using the following equation (6):

[0051] JPEG0007807574000017.jpg49170(6)

[0052] JPEG0007807574000018.jpg38170

[0053] It should be emphasized that the calculation of the non-T2 weighted magnetic resonance diffusion signal in S120, the fitting of the diffusion coefficient in S130, and the generation of the magnetic resonance diffusion imaging signal in S140 all adopt a pixel-by-pixel calculation method, i.e., any single pixel or group of pixels extracted from the complete image is applied to the calculation of generating the echo time-dependent magnetic resonance diffusion imaging signal.

[0054] Through S110 to S140, the magnetic resonance diffusion imaging signal generated in S140, the multiple echo time magnetic resonance non-diffusion weighted image acquired by the magnetic resonance scanner in S110, and the magnetic resonance multi-b-value diffusion weighted image are derived from the same individual.

[0055] Based on the method for generating an echo time-dependent magnetic resonance diffusion imaging signal provided by the above embodiment, the embodiment also provides a specific experimental example, as shown in FIG. 3, which includes the following steps:

[0056] S310: A magnetic resonance diffusion imaging image is acquired. On any clinical magnetic resonance scanner, image the human brain using a spin-echo-based planar echo imaging diffusion sequence, acquiring non-diffusion-weighted magnetic resonance images using three or more echo times, and acquiring multi-b-value diffusion-weighted magnetic resonance images using a single echo time. If the magnetic resonance scanner sequence parameters permit, acquire a counter-phase encoded non-diffusion-weighted image to facilitate preprocessing correction.

[0057] S320: Preprocess the magnetic resonance diffusion imaging image.

[0058] All acquired magnetic resonance diffusion imaging images were converted from Dicom image format to the NIFTI format commonly used in neuroimaging using software called dcm2niix, and then preprocessed using software packages called MRtrix3 and FSL. The preprocessing process included PCA noise reduction, Gibbs ripple artifact removal, main field distortion estimation and correction, eddy current distortion and head motion correction, and Rician background noise removal. Main field distortion estimation and correction was performed when the S310 acquired reverse-phase encoded images; otherwise, main field distortion estimation and correction was not performed. A preprocessed four-dimensional diffusion-weighted image was obtained. The first three dimensions were spatial dimensions, and the fourth dimension was the diffusion-weighted gradient dimension.

[0059] S330: Modeling and fitting multi-component signals.

[0060] The preprocessed diffusion imaging image is calculated, in accordance with S120, using the non-diffusion-weighted magnetic resonance images from multiple echo times to calculate non-T2-weighted magnetic resonance diffusion signals corresponding to various water components for each voxel. The quantitative T2 values ​​of various water components in human tissue may be set according to literature reference values. For example, under the classification assumptions of three water components, the T2 of intracellular water is 90 ms, the T2 of extracellular water is 60 ms, and the T2 of free water is 3000 ms. Next, in accordance with S130, the single-echo time magnetic resonance diffusion-weighted image and the non-T2-weighted magnetic resonance diffusion signals acquired in S120 are used to scan all voxels in the brain to calculate the diffusion coefficients corresponding to various water components for each voxel. The calculations in S120 and S130 must use consistent assumptions for the various water components, i.e., two or three classification assumptions for water components.

[0061] S340: Generate an echo time-dependent magnetic resonance diffusion image signal.

[0062] Using the magnetic resonance diffusion weighted image of a single echo time acquired in S330, the magnetic resonance diffusion signals without T2 weighting of various water components in the human tissue, the diffusion coefficients of various water components in the human tissue, and the quantitative T2 values ​​of various water components in the human tissue, the magnetic resonance diffusion imaging signal of an arbitrary echo time is calculated for each voxel and generated in S140. After scanning all voxels, a four-dimensional diffusion weighted image is generated that is the same as the matrix of the preprocessed image.

[0063] In any case, the method for generating an echo time-dependent magnetic resonance diffusion imaging signal provided by the embodiment decomposes and reconstructs the original magnetic resonance diffusion signal into multiple components, extracts non-T2 weighted magnetic resonance diffusion signals and diffusion coefficients corresponding to the multiple components while fully preserving the physiological information of the original signal, generates weighted diffusion signals under any TE, and can eliminate measurement deviations of diffusion coefficients caused by echo times that do not match the diffusion model.

[0064] Based on the same inventive concept, as shown in FIG. 4, an embodiment also provides an echo-time-dependent magnetic resonance diffusion imaging signal generating device 400. The echo-time-dependent magnetic resonance diffusion imaging signal generating device 400 includes an image acquisition module 410, a multi-component diffusion signal calculation module 420, a multi-component diffusion coefficient calculation module 430, and a diffusion imaging signal generation module 440. The image acquisition module 410 is used to acquire a non-diffusion-weighted magnetic resonance image acquired using multiple echo times and a multi-b-value diffusion-weighted magnetic resonance image acquired using a single echo time. The multi-component diffusion signal calculation module 420 is used to calculate a voxel-by-voxel magnetic resonance diffusion signal that does not weight transverse relaxation time values ​​corresponding to various water components in the human tissue, based on the non-diffusion-weighted magnetic resonance image and the transverse relaxation time values ​​of various water components in the human tissue. The multi-component diffusion coefficient calculation module 430 is used to calculate a voxel-by-voxel diffusion coefficient corresponding to various water components in the human tissue, based on the multi-b-value diffusion-weighted magnetic resonance image, the magnetic resonance diffusion signal, and the transverse relaxation time values. The diffusion imaging signal generation module 440 is used to calculate and generate a magnetic resonance multi-b-value diffusion weighted image, a magnetic resonance diffusion signal, a transverse relaxation time value, and a diffusion coefficient for each voxel acquired using any echo time, according to the magnetic resonance diffusion signal.

[0065] When the apparatus for generating an echo time-dependent magnetic resonance diffusion imaging signal provided in the above embodiments generates a magnetic resonance diffusion imaging signal, it should be described by way of example based on the division of the above functional modules, and the above functions may be achieved by different functional modules as needed. That is, to achieve all or part of the above functions, the internal structure of the terminal or server is divided into different functional modules. Furthermore, the apparatus for generating an echo time-dependent magnetic resonance diffusion imaging signal provided in the above embodiments and the method for generating an echo time-dependent magnetic resonance diffusion imaging signal according to the above embodiments belong to the same inventive concept, and the details of the realization process thereof should be referred to the embodiment of the method for generating an echo time-dependent magnetic resonance diffusion imaging signal and will not be described again here.

[0066] Based on the same inventive concept, an embodiment also provides a computing device including a memory and one or more processors, wherein the memory stores executable code, which, when executed by the one or more processors, is used to implement the above-mentioned method for generating an echo time-dependent magnetic resonance diffusion imaging signal, specifically including the following steps:

[0067] S110: Obtaining a magnetic resonance non-diffusion weighted image acquired using multiple echo times and a magnetic resonance multi-b-value diffusion weighted image acquired using a single echo time.

[0068] S120: Calculate, for each voxel, a magnetic resonance diffusion signal that does not weight non-transverse relaxation time values ​​corresponding to various water components in the human tissue, based on the magnetic resonance non-diffusion weighted image and the transverse relaxation time values ​​of various water components in the human tissue.

[0069] S130: Calculate the diffusion coefficients corresponding to various water components in human tissue for each voxel according to the magnetic resonance multi-b-value diffusion weighted image, magnetic resonance diffusion signal and transverse relaxation time value.

[0070] S140: A magnetic resonance multi-b-value diffusion weighted image, a magnetic resonance diffusion imaging signal acquired using an arbitrary echo time, is calculated for each voxel by the magnetic resonance diffusion signal, transverse relaxation time value, and diffusion coefficient to generate a magnetic resonance diffusion weighted image.

[0071] As shown in FIG. 5, at the hardware level, the computing device provided by the embodiment includes not only a processor and memory, but also hardware necessary for other services, such as an internal bus, a network interface, and internal memory. The memory is non-volatile memory, and the processor reads the corresponding computer program from the non-volatile memory to the internal memory and executes it to realize the method for generating echo time-dependent magnetic resonance diffusion imaging signals described above in S110 to S140. Of course, the present invention does not exclude other implementation methods other than software, such as logic devices or a combination of software and hardware. In other words, the execution entity of the following processing flow is not limited to each logic unit, but may also be hardware or a logic device.

[0072] Based on the same inventive concept, an embodiment also provides a computer-readable storage medium having a program stored therein, which, when executed by a processor, realizes the above-mentioned method for generating an echo time-dependent magnetic resonance diffusion imaging signal, specifically including the following steps:

[0073] S110: Obtaining a magnetic resonance non-diffusion weighted image acquired using multiple echo times and a magnetic resonance multi-b-value diffusion weighted image acquired using a single echo time.

[0074] S120: Calculate, for each voxel, a magnetic resonance diffusion signal that does not weight non-transverse relaxation time values ​​corresponding to various water components in the human tissue, based on the magnetic resonance non-diffusion weighted image and the transverse relaxation time values ​​of various water components in the human tissue.

[0075] S130: Calculate the diffusion coefficients corresponding to various water components in human tissue for each voxel according to the magnetic resonance multi-b-value diffusion weighted image, magnetic resonance diffusion signal and transverse relaxation time value.

[0076] S140: A magnetic resonance multi-b-value diffusion weighted image, a magnetic resonance diffusion imaging signal acquired using an arbitrary echo time, is calculated for each voxel by the magnetic resonance diffusion signal, transverse relaxation time value, and diffusion coefficient to generate a magnetic resonance diffusion weighted image.

[0077] In embodiments, computer-readable storage media include non-volatile and volatile media, removable and non-removable media, and may be implemented by any method or technology for storing information. Information may be computer-readable instructions, data structures, program modules, or other data. Computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage devices, cassettes, magnetic tapes, magnetic tape, magnetic disk storage devices, other magnetic storage devices, or any other non-transmission media used to store information accessible to a computing device. As defined herein, computer-readable storage media does not include transitory computer-readable media, such as modulated data signals or carrier waves.

[0078] The above specific embodiments are intended to explain in detail the technical solutions and beneficial effects of the present invention, but the above descriptions are only some embodiments of the present invention and are not used to limit the protection scope of the present invention. It should be noted that those skilled in the art may make some modifications and alterations without departing from the spirit and scope of the present invention, and all of them fall within the protection scope of the present invention.

Claims

1. obtaining magnetic resonance non-diffusion weighted images acquired using multiple echo times and magnetic resonance multi-b-value diffusion weighted images acquired using a single echo time; a step of calculating, for each voxel, a magnetic resonance diffusion signal without weighting of the transverse relaxation time values ​​corresponding to the various water components in the human tissue, based on the magnetic resonance non-diffusion weighted image and the transverse relaxation time values ​​of the various water components in the human tissue, wherein the various water components in the human tissue are classified into two categories, one category being a category in which two water components exist in the human tissue, including intracellular water and extracellular water, and the other category being a category in which three water components exist in the human tissue, including intracellular water, extracellular water, and free water; When the various water components in the human tissue include intracellular water and extracellular water, the unweighted magnetic resonance diffusion signal of the transverse relaxation time value is calculated for each voxel using the following equation (1): When the various water components in the human tissue include intracellular water, extracellular water, and free water, the unweighted magnetic resonance diffusion signal of the transverse relaxation time value is calculated for each voxel using the following equation (2): calculating diffusion coefficients corresponding to various water components in the human tissue for each voxel based on the magnetic resonance multi-b-value diffusion weighted image, the magnetic resonance diffusion signal, and the transverse relaxation time value; When the various water components in the human tissue include intracellular water and extracellular water, the diffusion coefficients corresponding to the various water components in the human tissue are calculated for each voxel using the following equation (3): When the various water components in the human tissue include intracellular water, extracellular water, and free water, the diffusion coefficients corresponding to the various water components in the human tissue are calculated for each voxel using the following equation (4): calculating a magnetic resonance diffusion imaging signal acquired using an arbitrary echo time for each voxel using the magnetic resonance multi-b-value diffusion weighted image, the magnetic resonance diffusion signal, the transverse relaxation time value, and the diffusion coefficient; When the various water components in the human tissue include intracellular water and extracellular water, the magnetic resonance diffusion imaging signal collected using an arbitrary echo time is calculated for each voxel using the following equation (5) to generate: （５） When the various water components in the human tissue include intracellular water, extracellular water, and free water, the magnetic resonance diffusion imaging signal collected using an arbitrary echo time is calculated for each voxel using the following equation (6), to generate: （６） 10. A method for generating an echo time-dependent magnetic resonance diffusion imaging signal, comprising:

2. 2. The method for generating an echo time-dependent magnetic resonance diffusion imaging signal according to claim 1, wherein the same magnetic resonance diffusion imaging sequence is used when acquiring the magnetic resonance non-diffusion-weighted image and the magnetic resonance multi-b-value diffusion-weighted image, and except for two magnetic resonance sequence parameters, echo time or diffusion b-value, which are set to multiple values ​​within a certain range, the remaining magnetic resonance sequence parameters are set to the same, wherein when acquiring the magnetic resonance non-diffusion-weighted image, the diffusion b-value is set to zero and the echo time is set to at least two, and when acquiring the magnetic resonance multi-b-value diffusion-weighted image, the echo time is set to a single fixed value and the diffusion b-value is set to at least two.

3. 2. The method for generating echo time-dependent magnetic resonance diffusion imaging signals according to claim 1, characterized in that, when calculating the diffusion coefficient, a single fitting calculation is performed in the vector direction of each diffusion weighting gradient for the magnetic resonance multi-b-value diffusion weighted image signal used.

4. The apparatus for generating an echo time-dependent magnetic resonance diffusion image signal includes an image acquisition module, a multi-component diffusion signal calculation module, a multi-component diffusion coefficient calculation module, and a diffusion imaging signal generation module; the image acquisition module is used to acquire magnetic resonance non-diffusion weighted images acquired using multiple echo times and magnetic resonance multi-b-value diffusion weighted images acquired using a single echo time; the multi-component diffusion signal calculation module is used to calculate, for each voxel, a magnetic resonance diffusion signal that does not weight the transverse relaxation time values ​​corresponding to various water components in the human tissue according to the magnetic resonance non-diffusion weighted image and the transverse relaxation time values ​​of various water components in the human tissue, and the various water components in the human tissue are classified into two categories: one category indicates that there are two water components in the human tissue, including intracellular water and extracellular water; and the other category indicates that there are three water components in the human tissue, including intracellular water, extracellular water, and free water; When the various water components in the human tissue include intracellular water and extracellular water, the unweighted magnetic resonance diffusion signal of the transverse relaxation time value is calculated for each voxel using the following equation (1): When the various water components in the human tissue include intracellular water, extracellular water, and free water, the unweighted magnetic resonance diffusion signal of the transverse relaxation time value is calculated for each voxel using the following equation (2): The multi-component diffusion coefficient calculation module is used to calculate diffusion coefficients corresponding to various water components in human tissue for each voxel according to the magnetic resonance multi-b-value diffusion weighted image, the magnetic resonance diffusion signal, and the transverse relaxation time value; When the various water components in the human tissue include intracellular water and extracellular water, the diffusion coefficients corresponding to the various water components in the human tissue are calculated for each voxel using the following equation (3): When the various water components in the human tissue include intracellular water, extracellular water, and free water, the diffusion coefficients corresponding to the various water components in the human tissue are calculated for each voxel using the following equation (4): the diffusion imaging signal generation module is used to calculate and generate a magnetic resonance diffusion imaging signal acquired using an arbitrary echo time by the magnetic resonance multi-b-value diffusion weighted image, the magnetic resonance diffusion signal, the transverse relaxation time value, and the diffusion coefficient for each voxel; When the various water components in the human tissue include intracellular water and extracellular water, the magnetic resonance diffusion imaging signal collected using an arbitrary echo time is calculated for each voxel using the following equation (5) to generate: （５） When the various water components in the human tissue include intracellular water, extracellular water, and free water, the magnetic resonance diffusion imaging signal collected using an arbitrary echo time is calculated for each voxel using the following equation (6), to generate: （６）

5. 1. A computing device including a memory and one or more processors, the memory storing executable code, comprising: A computing device characterized in that it is used to implement the method for generating an echo time-dependent magnetic resonance diffusion imaging signal according to any one of claims 1 to 3 when one or more processors execute executable code.

6. A computer-readable storage medium having a program stored thereon, the program implementing the method for generating an echo time-dependent magnetic resonance diffusion imaging signal according to any one of claims 1 to 3 when executed by a processor.

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