Brain lymphatic system function quantitative measurement method and device and storage medium

Abstract

The invention discloses a method and equipment for quantitatively measuring functions of a brain lymphatic system and a storage medium. The method comprises the following steps: receiving diffusion weighted imaging, diffusion tensor imaging, three-dimensional T2 weighted imaging and peripheral gap structure masks of a region of interest; calculating a registration rapid diffusion rate diagram, a registration slow diffusion rate diagram and a registration water molecule perfusion diagram; calculating a rapid diffusion average value of water molecules in the perivascular gap, a slow diffusion average value of water molecules in the perivascular gap, and a perfusion level average value of small vascular structures in the perivascular gap; and calculating the functions of the brain-like lymphatic system. A contrast agent is not needed, so that the risk of a patient is reduced; the scanning time is shorter, and the clinical feasibility is improved; the sensitivity to motion artifacts is low, and the method is suitable for research of complex brain regions; and the calculation complexity is greatly optimized, and the method is particularly suitable for accurate characterization of the fiber structure. And a more accurate and efficient tool is provided for non-invasive and quantitative evaluation of the GS function of the lymphatic system.

Description

Technical Field

[0001] The present invention belongs to the field of nuclear magnetic resonance technology, and in particular relates to a method, a device and a storage medium for quantitatively measuring the function of the brain lymphatic system. Background Art

[0002] The glymphatic system (GS) is an important component of the central nervous system to maintain normal function and is considered to be one of the main waste removal systems in the brain. It begins around the arteries of the brain, where cerebrospinal fluid infiltrates along the outer wall of the artery and passes through the para-arterial space into the deep part of the brain parenchyma. When the cerebrospinal fluid enters the brain tissue, it promotes the exchange of cerebrospinal fluid and interstitial fluid through astrocytes, and the cleared waste is discharged from the brain along with the cerebrospinal fluid through the perivenous space. Among them, the perivascular space plays a key role in GS. It is an important channel for the exchange of cerebrospinal fluid and interstitial fluid in this system and is responsible for the transportation and removal of waste. In the study of GS function, the application of imaging technology is crucial. However, existing imaging technology has many limitations, which makes it insufficient in the quantitative study of GS function. Although diffusion tensor imaging (DTI) can preliminarily explore the function of GS, its resolution is relatively limited and it is difficult to accurately characterize the complex microstructure; dynamic contrast-enhanced MRI (DCE-MRI) and static contrast-enhanced MRI (CE-MRI) can provide high-resolution dynamic and static images, but rely on the use of contrast agents, which not only increases the burden on patients but may also cause safety issues; arterial spin labeling (ASL) does not require the use of contrast agents, but the resolution is still not ideal. In addition, although susceptibility-weighted imaging (SWI) and diffusion spectrum imaging (DSI) can visualize the function of GS under certain conditions, they are sensitive to motion artifacts and have a long imaging time, which limits their clinical application. Therefore, existing technologies face challenges in terms of resolution, imaging time, patient safety, and motion artifact control. Summary of the invention

[0003] The purpose of the present invention is to provide a method, device and storage medium for quantitative measurement of brain lymphatic system function in view of the above-mentioned problems existing in the prior art. By setting multiple b values, the diffusion characteristic data of tissues under different diffusion sensitivities can be obtained. The fast diffusion coefficient (Dfast) reflects the microscopic blood flow in the capillaries, while the slow diffusion coefficient (Dslow) reveals the pure molecular diffusion process, thereby achieving quantitative measurement of GS function. Combined with three-dimensional T2-weighted imaging T2WI, quantitative analysis of the region of interest can be performed, further quantifying the microcirculation perfusion effect in the voxel, and improving the measurement accuracy.

[0004] The above-mentioned purpose of the present invention is achieved by the following technical means:

[0005] A method for quantitatively measuring the function of the brain glymphatic system comprises the following steps:

[0006] Step 1: receiving diffusion weighted imaging, diffusion tensor imaging, three-dimensional T2-weighted imaging, and perivascular space structure mask of the region of interest,

[0007] Step 2: Calculate the fast diffusion rate map, the slow diffusion rate map, and the water molecule perfusion map and perform spatial registration to obtain the registered fast diffusion rate map, the registered slow diffusion rate map, and the registered water molecule perfusion map;

[0008] Step 3: calculating the average rapid diffusion rate of water molecules in the perivascular space, the average slow diffusion rate of water molecules in the perivascular space, and the average perfusion level of small vascular structures in the perivascular space based on the registered rapid diffusion rate map, the registered slow diffusion rate map, and the registered water molecule perfusion map;

[0009] Step 4: Calculate the function of the cerebral glymphatic system based on the average value of the rapid diffusion of water molecules in the perivascular space, the average value of the slow diffusion of water molecules in the perivascular space, and the average value of the perfusion level of small vascular structures in the perivascular space.

[0010] As mentioned above, the rapid diffusion rate diagram is obtained based on the following formula:

[0011] S(b)=S0[f×e -bDfast +(1-f)×e -bDslow ]

[0012] Among them, S(b) is the signal intensity of diffusion-weighted imaging using the b value, S0 is the signal intensity of unweighted diffusion-weighted imaging, f is the perfusion fraction, Dfast is the fast diffusion coefficient, Dslow is the slow diffusion coefficient, and the fast diffusion coefficient corresponding to each voxel constitutes the fast diffusion coefficient map.

[0013] As described above, the slow diffusion rate map is obtained by the following steps:

[0014] b value is greater than or equal to 500s / mm 2 When , the slow diffusion coefficient is obtained based on the formula Dslow = -ln(S(b) / S0) / b;

[0015] b value is less than 500s / mm 2 When, based on the formula S(b) = S0[f×e -bDfast +(1-f)×e -bDslow ]Fitting to obtain the slow diffusion coefficient;

[0016] S(b) is the signal intensity of diffusion-weighted imaging using the b value, S0 is the signal intensity of unweighted diffusion-weighted imaging, f is the perfusion fraction, Dfast is the fast diffusion coefficient, Dslow is the slow diffusion coefficient, and the slow diffusion coefficient corresponding to each voxel constitutes the slow diffusion coefficient map.

[0017] As mentioned above, the water molecule perfusion map is obtained based on the following formula:

[0018] D perf =D fast -D slow

[0019] Among them, D perf is the water molecule perfusion coefficient, Dfast is the fast diffusion coefficient, Dslow is the slow diffusion coefficient, and the water molecule perfusion coefficients corresponding to each voxel constitute the water molecule perfusion map.

[0020] As described above, the registered fast diffusion rate map, the registered slow diffusion rate map, and the registered water molecule perfusion map are obtained based on the following steps:

[0021] The three-dimensional T2-weighted imaging is used as a reference to spatially register the fast diffusion rate map, the slow diffusion rate map, and the water molecule perfusion map to obtain the registered fast diffusion rate map, the registered slow diffusion rate map, and the registered water molecule perfusion map.

[0022] As mentioned above, the area of ​​the perivascular space structure mask of the region of interest is assigned a value of 1, and the rest of the area is assigned a value of 0.

[0023] The average value of the rapid diffusion of water molecules in the perivascular space, the average value of the slow diffusion of water molecules in the perivascular space, and the average value of the perfusion level of small blood vessel structures in the perivascular space are obtained based on the following steps:

[0024] The perivascular space structure mask is respectively multiplied point by point with the registered fast diffusion rate map, the registered slow diffusion rate map, and the registered water molecule perfusion map to calculate the fast diffusion map of water molecules in the perivascular space, the slow diffusion map of water molecules in the perivascular space, and the perfusion level of small blood vessel structures in the perivascular space;

[0025] The fast diffusion map of water molecules in the perivascular space, the slow diffusion map of water molecules in the perivascular space, and the average signal intensity of each voxel of the perfusion level of small vascular structures in the perivascular space are calculated to obtain the fast diffusion average of water molecules in the perivascular space, the slow diffusion average of water molecules in the perivascular space, and the perfusion level average of small vascular structures in the perivascular space.

[0026] As mentioned above, the function of the brain glymphatic system is obtained based on the following formula:

[0027] GS function=a×Mean PVSfast+b×Mean PVSslow–c×Mean PVSperf

[0028] Among them, GS function is the function of the brain lymphatic system, Mean PVSfast is the average value of the fast diffusion of water molecules in the perivascular space, Mean PVSslow is the average value of the slow diffusion of water molecules in the perivascular space, MeanPVSperf is the average value of the perfusion level of small vascular structures in the perivascular space, a, b, and c are weights, respectively, where a is greater than b.

[0029] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned measurement method when executing the computer program.

[0030] A computer-readable storage medium stores a computer program, which implements the steps of the above-mentioned measurement method when executed by a processor.

[0031] A computer program product comprises a computer program, which implements the steps of the above-mentioned measurement method when executed by a processor.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The multi-b-value diffusion tensor imaging DTI used in the present invention has the advantages of low computational complexity, high processing robustness, short scanning time and a wide range of clinical application scenarios, and is particularly suitable for the study of fiber structure and routine clinical use.

[0034] 2. By combining three-dimensional T2 weighted imaging T2WI, the present invention can perform more accurate quantitative measurement of the region of interest (ROI).

[0035] 3. Diffusion tensor imaging (DTI) with multiple b values ​​can quantify the microcirculatory perfusion effect, the diffusion movement of pure water molecules and the diffusion movement related to perfusion within the voxel; this provides a new tool for the functional evaluation of the glymphatic system GS.

[0036] The present invention does not require contrast agents, which reduces patient risks; the scanning time is shorter, which improves clinical feasibility; the sensitivity to motion artifacts is low, which is suitable for the study of complex brain regions; and the computational complexity is greatly optimized, which is particularly suitable for the accurate characterization of fiber structures. Therefore, this new imaging technology not only makes up for the shortcomings of existing technologies, but also provides a more accurate and efficient tool for the non-invasive and quantitative evaluation of the GS function of the glymphatic system, opening up new possibilities for related basic research and clinical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0038] In order to facilitate those skilled in the art to understand and implement the present invention, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the implementation examples described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0039] Embodiment 1:

[0040] A method for quantitatively measuring the function of the brain glymphatic system comprises the following steps:

[0041] The human brain was imaged using a magnetic resonance imaging (MRI) device. The images collected included diffusion-weighted imaging (DWI, with 6 b values, including 0, 200, 400, 600, 800, and 1000) that can reflect the diffusion of water molecules, diffusion tensor imaging (DTI, with 64 directions in total), with a voxel size of 4 mm, and three-dimensional T2-weighted imaging (T2WI), with a voxel size of 1 mm.

[0042] Step 1: receiving diffusion weighted imaging DWI, diffusion tensor imaging DTI, three-dimensional T2 weighted imaging T2WI, and perivascular space structure mask of the region of interest, assigning a value of 1 to the region of the perivascular space structure mask, and assigning a value of 0 to the rest of the region.

[0043] The method for acquiring the perivascular space structure can be as follows: multi-directionally reconstruct the three-dimensional T2 weighted imaging T2WI, call the ITK-SNAP program to outline the perivascular space (PVS) structure, the perivascular space structure is manifested as linear and divergent strip-shaped high signals in the subcortical area, save the outline results, and perform mask (MASK) conversion on the three-dimensional T2 weighted imaging according to the outline results, assign 1 to the outlined area, and assign 0 to the remaining areas, so as to obtain the perivascular space structure mask.

[0044] Step 2: Calculate the fast diffusion rate map, slow diffusion rate map, and water molecule perfusion map and perform spatial registration to obtain the registered fast diffusion rate map RDfast, the registered slow diffusion rate map RDslow, and the registered water molecule perfusion map RDperf.

[0045] Step 2.1: Calculate the mean diffusion map (MD map) of the diffusion tensor imaging DTI. By calling the program of the post-processing workstation that comes with the MRI device, the mean diffusion map MD is automatically calculated; the mean diffusion map MD (Mean Diffusivitymap) is an indicator that reflects the overall diffusion characteristics of the tissue, usually the average value of the diffusion tensor imaging (DTI) in all directions. It can be used as the basic data for subsequent processing, especially for analyzing the microstructural changes of the tissue. For example, when studying whether the tissue has damage or pathological changes, it provides valuable information. In subsequent steps, such as when comparing with the fast diffusion coefficient (Dfast) or the slow diffusion coefficient (Dslow), the mean diffusion map MD will help provide background information. 0.

[0046] Step 2.2: Calculate the fast diffusion rate map, slow diffusion rate map, and water molecule perfusion map;

[0047] definition:

[0048] S(b) is the signal intensity of diffusion-weighted imaging when the b value is applied (signal intensity at a given b-value).

[0049] S0 is the signal intensity of diffusion-weighted imaging without diffusion weighting (ie, b=0).

[0050] b is the diffusion weight factor (b-value), which is related to the gradient strength, duration and interval time, and the unit is seconds per square millimeter (s / mm 2 ).

[0051] f is the perfusion fraction, which indicates the proportion of blood flow to the total signal, and its unit is dimensionless (fraction). The calculation formula is generally obtained by fitting multi-b-value diffusion-weighted imaging data, and can be calculated by linear or nonlinear fitting methods.

[0052] D is the true diffusion coefficient, which represents the diffusion coefficient (usually isotropic) and reflects the overall rate at which water molecules diffuse in tissues over time. It usually represents the diffusion process of pure water molecules and is expressed in square millimeters per second (mm 2 / s). The calculation formula can be obtained from the diffusion-weighted imaging data by performing a single exponential fit on the diffusion-weighted imaging at different b values: S(b) = S0 × e -bD The unit of D is mm 2 / s.

[0053] D * The apparent diffusion coefficient is the pseudo-diffusion coefficient, which is usually used to characterize some complex diffusion phenomena, especially in some cases, which may be related to blood flow. The unit is square millimeter per second (mm 2 / s). By measuring the signal intensity S at different b values b , and calculate the apparent diffusion coefficient D by fitting * .

[0054] Calculation of fast diffusion rate map: The fast diffusion rate map represents the fast diffusion component, which is usually related to the perfusion effect. In the IVIM model, by fitting multiple diffusion-weighted images with different b values, the fast diffusion coefficient Dfast is obtained using the following biexponential model fitting. The fast diffusion coefficient corresponding to each voxel constitutes the fast diffusion coefficient map:

[0055] S(b)=S0[f×e -bDfast +(1-f)×e -bDslow ] Formula 1

[0056] Where S(b) is the signal intensity of diffusion-weighted imaging using the b value, S0 is the signal intensity of unweighted diffusion-weighted imaging, f is the perfusion fraction, Dfast is the fast diffusion coefficient (diffusion related to perfusion), and Dslow is the slow diffusion coefficient (real tissue diffusion). The fast diffusion coefficients corresponding to each voxel constitute the fast diffusion coefficient map.

[0057] Calculation of the slow diffusion rate map: The slow diffusion rate map is the coefficient of the true diffusion of tissue water molecules, also known as the "pure diffusion coefficient". It usually represents the diffusion characteristics of tissue structure and corresponds to the slow diffusion component in the IVIM model.

[0058] For b value greater than or equal to 500s / mm 2 When , the slow diffusion coefficient Dslow is obtained based on the following formula 2:

[0059] Slow diffusion coefficient Dslow = -ln(S(b) / S0) / b. Formula 2

[0060] Formula 2 is suitable for data with larger b values ​​(i.e., higher diffusion weighting) to fit the slow diffusion component (i.e., pure diffusion part) of the tissue. At larger b values, generally greater than or equal to 500s / mm 2 When , the perfusion effect is usually weakened, and it mainly reflects the real diffusion of water molecules in the tissue. Therefore, it is more accurate to use this formula to fit the slow diffusion coefficient.

[0061] For b value less than 500s / mm 2When , the slow diffusion coefficient Dslow is obtained based on the fitting of formula 1.

[0062] The slow diffusion coefficients corresponding to each voxel constitute a slow diffusion coefficient map.

[0063] Calculation of water perfusion map: The water perfusion map is usually calculated by the following formula, which represents the pseudo-diffusion coefficient related to microcirculatory perfusion: D perf =D fast -D slow .

[0064] D perf is the water molecule perfusion coefficient, and the water molecule perfusion coefficient corresponding to each voxel constitutes the water molecule perfusion map. This parameter is sometimes used to describe the perfusion characteristics of tissue microvessels, especially in the IVIM model.

[0065] When calculating the fast diffusion rate map (RDfast), slow diffusion rate map (RDslow), and water molecule perfusion map (RDperf), the mean diffusion map MD provides a general background of the overall diffusion properties of the tissue. For example, changes in the mean diffusion map MD can help explain and understand changes in diffusion coefficients in different regions. In the fast diffusion rate map (RDfast), slow diffusion rate map (RDslow), and water molecule perfusion map (RDperf), if there are areas that show changes inconsistent with the mean diffusion map MD, it may indicate pathological changes or structural changes.

[0066] Step 2.3: Diffusion rate maps of different categories (fast diffusion rate map, slow diffusion rate map, water molecule perfusion map) are spatially registered. In this embodiment, a rigid registration algorithm is used, and the SPM 12 program of the public algorithm is called. The three-dimensional T2-weighted imaging T2WI is used as the reference image, and the diffusion rate map is used as the quasi-registered image for calculation. The registered images include a fast diffusion coefficient map (indicating the rate of rapid diffusion of water molecules in tissues. It is usually related to pseudo-diffusion or rapid flow, and may be related to blood perfusion), a slow diffusion coefficient map (indicating the rate of slow diffusion of water molecules in tissues. It usually reflects the restriction of the internal structure of the tissue on the diffusion of water molecules.) and a perfusion diffusion coefficient map (usually indicating the diffusion of water molecules due to blood perfusion. This parameter is usually used in the IVIM model to characterize the diffusion phenomenon of water molecules moving rapidly with blood flow), and are renamed RDfast, RDslow and RDperf, that is, the registered fast diffusion rate map RDfast, the registered slow diffusion rate map RDslow, and the registered water molecule perfusion map RDperf are obtained.

[0067] During the registration process, the fast diffusion rate map (RDfast), slow diffusion rate map (RDslow), and water molecule perfusion map (RDperf) may involve comparison or alignment issues. During registration, the mean diffusion map MD as a reference image can help verify the accuracy and consistency of the registration. After registering these diffusion rate maps (Dfast, Dslow, Dperf) with three-dimensional T2-weighted imaging (T2WI), the mean diffusion map MD can be used as an additional check tool to confirm whether the registration is correct.

[0068] Step 3: Calculate the diffusion characteristics of water molecules in the perivascular space

[0069] Step 3.1: Perform point-by-point product operations on the perivascular space structure mask MASK in step 1 with the registered fast diffusion rate map RDfast, the registered slow diffusion rate map RDslow, and the registered water molecule perfusion map RDperf, respectively, to calculate the fast diffusion map PVSfast of water molecules in the perivascular space (reflecting the fast transport characteristics of water molecules), the slow diffusion map PVSslow of water molecules in the perivascular space (reflecting the slow transport characteristics of binding with water molecules), and the perfusion level PVSperf of small blood vessel structures in the perivascular space (reflecting the influence of blood perfusion), that is, MASK×RDfast=PVSfast, MASK×RDslow=PVSslow, MASK×RDperf=PVSperf.

[0070] Step 3.2: Extract the average signal enhancement of the water molecule diffusion map in each perivascular space, that is, calculate the average signal intensity of each voxel of the fast diffusion map PVSfast of water molecules in the perivascular space, the slow diffusion map PVSslow of water molecules in the perivascular space, and the perfusion level PVSperf of small vascular structures in the perivascular space. Call ITK-SNAP software to calculate the fast diffusion average Mean PVSfast of water molecules in the perivascular space, the slow diffusion average Mean PVSslow of water molecules in the perivascular space, and the perfusion level average Mean PVSperf of small vascular structures in the perivascular space.

[0071] Step 4: Calculate the glymphatic system function reference

[0072] Step 4.1: Since the perivascular space is a structure rich in free water, the fast diffusion rate diagram reflects more the rapid transport of water molecules in the perivascular space and has the largest weight, while the slow diffusion rate diagram reflects the transport of bound water and has a smaller weight. The water molecule perfusion diagram reflects the perfusion level of small vascular structures in the perivascular space and needs to be removed when evaluating the glymphatic system function. Therefore, the brain glymphatic system function GS function is defined as GS function = a×Mean PVSfast+b×Mean PVSslow–c×Mean PVSperf.

[0073] Step 4.2: In the above formula, a, b, and c are all weights, which can be adjusted according to actual conditions, and generally a is selected to be greater than b. In this embodiment, a=2, b=1, and c=1.

[0074] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing related hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods.

[0075] Embodiment 2:

[0076] In this embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

[0077] Embodiment 3:

[0078] In this 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.

[0079] Embodiment 4:

[0080] In this embodiment, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0081] It should be noted that the embodiments described in the present invention are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the described embodiments or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the attached claims.

Claims

1. A method for quantitatively measuring the function of the brain glymphatic system, characterized in that: The following steps are involved: Step 1: receiving diffusion weighted imaging, diffusion tensor imaging, three-dimensional T2-weighted imaging, and perivascular space structure mask of the region of interest, Step 2: Calculate the fast diffusion rate map, the slow diffusion rate map, and the water molecule perfusion map and perform spatial registration to obtain the registered fast diffusion rate map, the registered slow diffusion rate map, and the registered water molecule perfusion map; Step 3: calculating the average rapid diffusion rate of water molecules in the perivascular space, the average slow diffusion rate of water molecules in the perivascular space, and the average perfusion level of small vascular structures in the perivascular space based on the registered rapid diffusion rate map, the registered slow diffusion rate map, and the registered water molecule perfusion map; Step 4: Calculate the function of the cerebral glymphatic system based on the average value of the rapid diffusion of water molecules in the perivascular space, the average value of the slow diffusion of water molecules in the perivascular space, and the average value of the perfusion level of small vascular structures in the perivascular space.

2. The method for quantitatively measuring the function of the brain glymphatic system according to claim 1, characterized in that: The rapid diffusion rate diagram is obtained based on the following formula fitting: S(b)=S0[f×e -bDfast +(1-f)×e -bDslow ] Among them, S(b) is the signal intensity of diffusion-weighted imaging using the b value, S0 is the signal intensity of unweighted diffusion-weighted imaging, f is the perfusion fraction, Dfast is the fast diffusion coefficient, Dslow is the slow diffusion coefficient, and the fast diffusion coefficient corresponding to each voxel constitutes the fast diffusion coefficient map.

3. The method for quantitatively measuring the function of the brain glymphatic system according to claim 1, characterized in that: The slow diffusion rate graph is obtained by the following steps: b value is greater than or equal to 500s / mm 2 When , the slow diffusion coefficient is obtained based on the formula Dslow = -ln(S(b) / S0) / b; b value is less than 500s / mm 2 When, based on the formula S(b) = S0[f×e -bDfast +(1-f)×e -bDslow ]Fitting to obtain the slow diffusion coefficient; S(b) is the signal intensity of diffusion-weighted imaging using the b value, S0 is the signal intensity of unweighted diffusion-weighted imaging, f is the perfusion fraction, Dfast is the fast diffusion coefficient, Dslow is the slow diffusion coefficient, and the slow diffusion coefficient corresponding to each voxel constitutes the slow diffusion coefficient map.

4. The method for quantitatively measuring the function of the brain glymphatic system according to claim 1, characterized in that: The water molecule perfusion map is obtained based on the following formula: D perf =D fast -D slow Among them, D perf is the water molecule perfusion coefficient, Dfast is the fast diffusion coefficient, Dslow is the slow diffusion coefficient, and the water molecule perfusion coefficients corresponding to each voxel constitute the water molecule perfusion map.

5. The method for quantitatively measuring the function of the brain glymphatic system according to claim 1, characterized in that: The registered fast diffusion rate map, the registered slow diffusion rate map, and the registered water molecule perfusion map are obtained based on the following steps: The three-dimensional T2-weighted imaging is used as a reference to spatially register the fast diffusion rate map, the slow diffusion rate map, and the water molecule perfusion map to obtain the registered fast diffusion rate map, the registered slow diffusion rate map, and the registered water molecule perfusion map.

6. A method for quantitatively measuring the function of the brain glymphatic system according to claim 1, characterized in that: The area of ​​the perivascular space structure mask of the region of interest is assigned a value of 1, and the rest of the area is assigned a value of 0. The average value of the rapid diffusion of water molecules in the perivascular space, the average value of the slow diffusion of water molecules in the perivascular space, and the average value of the perfusion level of small blood vessel structures in the perivascular space are obtained based on the following steps: The perivascular space structure mask is respectively multiplied point by point with the registered fast diffusion rate map, the registered slow diffusion rate map, and the registered water molecule perfusion map to calculate the fast diffusion map of water molecules in the perivascular space, the slow diffusion map of water molecules in the perivascular space, and the perfusion level of small blood vessel structures in the perivascular space; The fast diffusion map of water molecules in the perivascular space, the slow diffusion map of water molecules in the perivascular space, and the average signal intensity of each voxel of the perfusion level of small vascular structures in the perivascular space are calculated to obtain the fast diffusion average of water molecules in the perivascular space, the slow diffusion average of water molecules in the perivascular space, and the perfusion level average of small vascular structures in the perivascular space.

7. A method for quantitatively measuring the function of the brain glymphatic system according to claim 1, characterized in that: The brain glymphatic system function is obtained based on the following formula: GS function=a×Mean PVSfast+b×Mean PVSslow–c×Mean PVSperf Among them, GS function is the function of the brain lymphatic system, Mean PVSfast is the average value of the fast diffusion of water molecules in the perivascular space, Mean PVSslow is the average value of the slow diffusion of water molecules in the perivascular space, Mean PVSperf is the average value of the perfusion level of small vascular structures in the perivascular space, a, b, and c are weights, respectively, where a is greater than b.

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 measurement method according to any one of claims 1 to 7 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 measurement method according to any one of claims 1 to 7 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 measurement method according to any one of claims 1 to 7 are implemented.

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