Cerebrospinal fluid dynamic quantitative evaluation method based on sodium ion concentration magnetic resonance imaging

Abstract

The invention discloses a cerebrospinal fluid dynamic quantitative evaluation method based on sodium ion concentration magnetic resonance imaging. The method comprises the following steps: acquiring a T1 weighted MP2-RAGE image and a plurality of continuous 23Na-MRI imaging images; calculating a correlation slope b between the sodium ion concentration TSC and the corresponding signal intensity; acquiring a cerebrospinal fluid structure mask; according to the cerebrospinal fluid structure mask and the plurality of continuous 23Na-MRI imaging images, obtaining sodium ion concentrations of the plurality of cerebrospinal fluids; fitting to obtain a scanning time-sodium ion concentration curve f (t) and calculating the change rate of the cerebrospinal fluid. According to the method, the change trend of the sodium ion concentration TSC of the cerebrospinal fluid can be dynamically observed by observing the scanning time-sodium ion concentration curve, the biochemical information of brain tissue cell activity, structural integrity and energy metabolism can be intuitively reflected, and the method can be carried out by children and reagent allergic patients without a tracer agent and a radiography contrast agent.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear magnetic resonance, and specifically relates to a method for dynamically quantifying cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging, which is applicable to evaluating the change rate of sodium ion concentration in cerebrospinal fluid. Background Art

[0002] Sodium is an essential ion in the human body. Sodium ions play a central role in many physiological processes of the human body and cells, including transmembrane electrochemical gradients and maintaining human homeostasis. Metabolic abnormalities and damage to cell membrane integrity will both cause changes in sodium ion concentration inside and outside cells. Magnetic resonance imaging based on sodium ion concentration (23Na-MRI) can non-invasively quantify the sodium ion concentration (tissue sodium concentration, TSC) in tissues. Changes in the sodium ion concentration TSC can reflect cell viability, structural integrity, and metabolic exchange, provide information such as changes in energy metabolism, and have been proven to reveal rapid treatment responses at the molecular level before morphological changes occur. Therefore, Na-based imaging has important value.

[0003] The metabolism and material transport in the brain tissue are mainly mediated by fluid flow. Cerebrospinal fluid (CSF) is a clear liquid in the ventricular cavity and around the brain, mainly secreted by the choroid plexus, and has functions such as buffering protection and material exchange. It plays an important role in the clearance of metabolic wastes in the brain and is a key factor in maintaining brain homeostasis. Therefore, observing and evaluating cerebrospinal fluid is of great significance for understanding the physiological changes of brain tissue. Existing cerebrospinal fluid evaluation techniques include contrast imaging based on radioactive isotope tracers, CT cisternography with iodine agents, magnetic resonance-based magnetization tracers, diffusion-weighted imaging, etc. The contrast-based methods require injecting contrast agents into the subjects, and invasive operations may be accompanied by risks of complications such as infection and bleeding, and there are many clinical use limitations, which are not applicable to patients with renal failure and patients allergic to contrast agents; the magnetization tracers based on hydrogen proton magnetic resonance and diffusion-weighted imaging scans have high requirements and long time, and the imaging quality of children and patients with poor cooperation may be poor. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for dynamically quantifying cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging in view of the above problems existing in the existing cerebrospinal fluid evaluation techniques. By continuously and rapidly scanning a selected layer multiple times, calculating the values of the sodium ion concentration TSC of the selected region of interest respectively, obtaining the sodium ion concentrations of multiple cerebrospinal fluids, establishing a coordinate system of sodium ion concentration TSC and scanning time, and fitting to obtain a scanning time-sodium ion concentration curve f(t), so as to reflect the change in sodium ion concentration in cerebrospinal fluid and dynamically observe the metabolic changes of cerebrospinal fluid.

[0005] The above object of the present invention is achieved by the following technical means:

[0006] A method for dynamic quantitative evaluation of cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging, characterized by comprising the following steps:

[0007] Step 1, obtain T1-weighted MP2-RAGE images and multiple consecutive 23Na-MRI imaging images;

[0008] Step 2, calculate the correlation slope b between the sodium ion concentration TSC and the corresponding signal intensity;

[0009] Step 3, obtain a cerebrospinal fluid structure mask;

[0010] Step 4, according to the cerebrospinal fluid structure mask and multiple consecutive 23Na-MRI imaging images, obtain the sodium ion concentrations of multiple cerebrospinal fluids;

[0011] Step 5: Fit to obtain the scan time-sodium ion concentration curve f(t) and calculate the cerebrospinal fluid change rate.

[0012] The T1-weighted MP2-RAGE images and multiple consecutive 23Na-MRI imaging images are generated by the following steps:

[0013] Collect data of multiple consecutive scans of the brain using a 23Na-MRI imaging coil to obtain multiple consecutive 23Na-MRI imaging images, and collect data of scanning the brain using a hydrogen proton imaging coil to obtain T1-weighted MP2-RAGE images.

[0014] The said step 2 includes the following steps:

[0015] Step 2.1, collect the scan data of test tubes with different sodium ion concentrations TSC in the 23Na-MRI imaging coil, obtain the signal intensity values of each voxel of the test tubes with different sodium ion concentrations TSC, and calculate the average value of the voxel signal intensities of each test tube as the signal intensity corresponding to the sodium ion concentration;

[0016] Step 2.2, construct a calculation formula for the linear correlation slope b between the sodium ion concentration TSC and the corresponding signal intensity and calculate the correlation slope b between the sodium ion concentration TSC and the corresponding signal intensity; the calculation formula for the correlation slope b between the sodium ion concentration TSC and the corresponding signal intensity is as follows:

[0017]

[0018] Where, I i is the signal intensity of the test tube at the i-th concentration; I m is the average value of the signal intensities of all concentration test tubes; S i is the sodium ion concentration TSC of the test tube at the i-th concentration; Sm TSC is the average value of the sodium ion concentration in the test tubes at all concentrations, and D is the total number of concentration types.

[0019] The cerebrospinal fluid structure mask is generated through the following steps:

[0020] Determine the cerebrospinal fluid region in the T1-weighted MP2-RAGE image obtained in Step 1 and outline it. According to the outlining result, perform a mask (MASK) conversion on the T1-weighted MP2-RAGE image, assign the value 1 to the outlined region, and assign the value 0 to the remaining regions to obtain the cerebrospinal fluid structure mask.

[0021] Step 4 includes the following steps:

[0022] Step 4.1: Overlay the cerebrospinal fluid structure mask obtained in Step 3 with the multiple consecutive 23Na-MRI imaging images obtained in Step 1 respectively to obtain the cerebrospinal fluid 23Na-MRI imaging image corresponding to each scan;

[0023] Step 4.2: Extract the average signal intensity of each cerebrospinal fluid 23Na-MRI imaging image respectively;

[0024] Step 4.3: Calculate the cerebrospinal fluid sodium ion concentration TSC at the corresponding slice during the nth scan based on the following formula CSFn ,

[0025] TSC CSFn =I 0 +b×I CSFn

[0026] where n is the serial number of the scan times, b is the linear correlation slope between the sodium ion concentration TSC and the signal intensity; for each scan, the corresponding cerebrospinal fluid 23Na-MRI imaging image and the background region can be obtained, and the signal intensity of the corresponding cerebrospinal fluid 23Na-MRI background region obtained in each scan is the same, I 0 is the average value of the signal intensity of the background region; I CSFn is the average value of the signal intensity of the cerebrospinal fluid region at the corresponding slice during the nth scan.

[0027] Step 5 includes the following steps:

[0028] Step 5.1: Set the scan time as the abscissa, the unit of the abscissa is the time interval between each scan, set the sodium ion concentration TSC as the ordinate, and denote the cerebrospinal fluid sodium ion concentration at the corresponding slice of the nth scan time obtained in Step 4 as TSC CSFn , N is the total number of scans, and construct the following polynomial:

[0029] TSC CSFn =a 0 +a 1T 1 +a 2 T 2 +...+a n T n

[0030] wherein, a 0 , a 1 , a 2 ,..., a n are all correlation coefficients; T 1 , T 2 ,..., T n are the scanning times from the 1st to the nth time,

[0031] Use the least squares method to fit the above polynomial to determine the values of the correlation coefficients a 0 , a 1 , a 2 ,..., a n , and obtain the scanning time - sodium ion concentration curve f(t) by fitting,

[0032] Step 5.2. Calculate the scanning time T n when the sodium ion concentration in cerebrospinal fluid relative to T n-1 the change rate R CSFn ,

[0033]

[0034] wherein, T n and T n-1 are the scanning time of the nth time and the scanning time of the (n - 1)th time respectively.

[0035] A computer device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, it implements each step of the above - mentioned cerebrospinal fluid dynamic quantitative evaluation method based on sodium ion concentration magnetic resonance imaging.

[0036] A computer - readable storage medium stores a computer program. When the computer program is executed by a processor, it implements each step of the above - mentioned cerebrospinal fluid dynamic quantitative evaluation method based on sodium ion concentration magnetic resonance imaging.

[0037] A computer program product includes a computer program. When the computer program is executed by a processor, it implements each step of the above - mentioned cerebrospinal fluid dynamic quantitative evaluation method based on sodium ion concentration magnetic resonance imaging.

[0038] The present invention has the following beneficial effects compared with the prior art:

[0039] 1. The continuous rapid multiple scanning method for the layer where the region of interest is selected based on the T1-weighted MP2-RAGE sequence image adopted by the present invention has the advantages of short scanning time, fast calculation speed, and wide clinical application scenarios, and is particularly suitable for the clinical routine monitoring application and academic research of cerebrospinal fluid evaluation;

[0040] 2. The present invention can dynamically observe the change rate of the cerebrospinal fluid sodium ion concentration TSC in the region of interest over time, intuitively reflect the change of brain metabolism, and provide a new tool for cerebrospinal fluid evaluation;

[0041] 3. By observing the scanning time-sodium ion concentration curve, the change trend of the sodium ion concentration TSC in the cerebrospinal fluid can be dynamically observed, which can intuitively reflect the biochemical information of brain tissue cell viability, structural integrity, and energy metabolism, reveal the brain physiological mechanism, make up for the defects of the existing technology, and help to further assist the clinical in-depth evaluation and prognosis prediction of the brain;

[0042] 4. The present invention does not require tracers and contrast agents, and can be performed on children and patients with reagent allergies. It has a wide clinical application range and provides a more accurate and efficient tool for cerebrospinal fluid evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic flow chart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0044] In order to facilitate the understanding and implementation of the present invention by those of ordinary skill in the art, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0045] Example 1:

[0046] A method for dynamic quantitative evaluation of cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging specifically includes the following steps:

[0047] Step 1: Obtain T1-weighted MP2-RAGE images and multiple consecutive 23Na-MRI imaging images.

[0048] The acquisition methods of the above 23Na-MRI imaging images and T1-weighted MP2-RAGE images can use the following steps: Collect the data of multiple consecutive scans of the brain using a 23Na-MRI imaging coil to obtain multiple consecutive 23Na-MRI imaging images that can reflect the sodium ion concentration TSC, and collect the data of the brain scan using a conventional hydrogen proton imaging coil to obtain T1-weighted MP2-RAGE images that can display the brain tissue structure.

[0049] Step 2: Calculate the correlation slope b between the sodium ion concentration and the corresponding signal intensity.

[0050] Step 2.1: Obtain the sodium ion concentration TSC and the corresponding signal intensity: Collect the scanning data of test tubes with different sodium ion concentrations TSC in the 23Na-MRI imaging coil, obtain the signal intensity values of each voxel of the test tubes with different sodium ion concentrations TSC, and calculate the average voxel signal intensity of each test tube as the signal intensity corresponding to the sodium ion concentration.

[0051] Step 2.2: Construct a calculation formula for the linear correlation slope b between the sodium ion concentration TSC and the corresponding signal intensity and calculate the correlation slope b between the sodium ion concentration TSC and the corresponding signal intensity. The sodium ion concentration TSC and the corresponding signal intensity are in a linear correlation relationship. The calculation of the correlation slope b between the sodium ion concentration TSC and the corresponding signal intensity is based on the following formula.

[0052]

[0053] where, I i is the signal intensity of the test tube at the i-th concentration; I m is the average value of the signal intensities of the test tubes at all concentrations; S i is the sodium ion concentration TSC of the test tube at the i-th concentration; S m is the average value of the sodium ion concentrations TSC of the test tubes at all concentrations, and D is the total number of concentration types.

[0054] Step 3: Obtain the cerebrospinal fluid structure mask.

[0055] The above cerebrospinal fluid structure mask can be obtained by the following steps: Determine the cerebrospinal fluid region in the T1-weighted MP2-RAGE image obtained in Step 1 and outline it. According to the outlining result, perform mask (MASK) conversion on the T1-weighted MP2-RAGE image, assign the outlined region a value of 1, and assign the remaining regions a value of 0 to obtain the cerebrospinal fluid structure mask.

[0056] Step 4: Obtain the sodium ion concentration of the cerebrospinal fluid based on the cerebrospinal fluid structure mask and multiple consecutive 23Na-MRI imaging images.

[0057] Step 4.1: Overlay the cerebrospinal fluid structure mask obtained in Step 3 and the multiple consecutive 23Na-MRI imaging images obtained in Step 1 respectively to obtain the cerebrospinal fluid 23Na-MRI imaging image corresponding to each scan.

[0058] Step 4.2: Extract the average signal intensity of each cerebrospinal fluid 23Na-MRI imaging image respectively, that is, calculate the average value of the signal intensities of all voxels in the cerebrospinal fluid region as the average cerebrospinal fluid region signal intensity, and define I CSFnis the average signal intensity of the cerebrospinal fluid region corresponding to the nth scan. In specific implementation, the average signal intensity I of the cerebrospinal fluid region corresponding to the nth scan can be automatically calculated using ITK-SNAP software CSFn .

[0059] Step 4.3: Calculation of the sodium ion concentration TSC of the cerebrospinal fluid corresponding to the nth scan CSFn of

[0060] TSC CSFn =I 0 +b×I CSFn

[0061] n is the serial number of the scan times, b is the linear correlation slope between the sodium ion concentration TSC and the corresponding signal intensity; for each scan, the corresponding cerebrospinal fluid 23Na-MRI imaging image and the background region can be obtained, and the signal intensity of the background region corresponding to the cerebrospinal fluid 23Na-MRI obtained each time is the same, I 0 is the average value of the signal intensity of the background region; I CSFn is the average signal intensity of the cerebrospinal fluid region corresponding to the nth scan.

[0062] Step 5: Fit to obtain the scan time - sodium ion concentration curve f(t) and calculate the cerebrospinal fluid change rate.

[0063] Step 5.1: Set the scan time as the abscissa, the unit of the abscissa is the time interval between each scan, and set the sodium ion concentration TSC as the ordinate. Denote the sodium ion concentration of the cerebrospinal fluid corresponding to the nth scan time obtained in Step 4 as TSC CSFn (n = 1, TSC CSF1 ; n = 2, TSC CSF2 ; n = 3, TSC CSF3 ; n = N, TSC CSFN ; N is the total number of scans, n is the serial number of the scan times), and construct the following polynomial:

[0064] TSC CSFn =a 0 +a 1 T 1 +a 2 T 2 +...+a n T n

[0065] TSC CSFn is the sodium ion concentration of the cerebrospinal fluid corresponding to the nth scan, a 0 , a 1 , a 2 ,..., a nAll are correlation coefficients; T 1 , T 2 ,..., T n are the scanning times from the 1st to the nth time.

[0066] Use the least squares method to perform Vandermonde matrix calculation on the above polynomial to determine the correlation coefficients a 0 , a 1 , a 2 ,..., a n values, and fit to obtain the scanning time - sodium ion concentration curve f(t).

[0067] By observing the scanning time - sodium ion concentration curve, the change trend of the sodium ion concentration in cerebrospinal fluid can be visually seen.

[0068] Step 5.2: Determination of the change rate of cerebrospinal fluid sodium ion concentration (TSC). The scanning time T n when the cerebrospinal fluid sodium ion concentration relative to T n-1 when the change rate R CSFn is:

[0069]

[0070] R CSFn is the change rate of cerebrospinal fluid sodium ion concentration at the nth scan; T n and T n-1 are the nth scan time and the (n - 1)th scan time respectively.

[0071] Select the time interval to be observed to obtain the change rate R CSFn of the sodium ion concentration in cerebrospinal fluid during this time period.

[0072] Those of ordinary skill in the art can understand that all or part of the processes in implementing the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non - volatile computer - readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods.

[0073] Embodiment 2:

[0074] In this embodiment, a computer device is further provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, it implements each step in the above Embodiment 1.

[0075] Embodiment 3:

[0076] 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, it implements each step in the above Embodiment 1.

[0077] Example 4:

[0078] In this embodiment, a computer program product is provided, including a computer program which, when executed by a processor, implements the steps in Embodiment 1 above.

[0079] It should be noted that the embodiments described in the present invention are only illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described embodiments or use similar means for substitution, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A method for dynamic quantitative evaluation of cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging, characterized in that: The following steps are involved: Step 1, acquiring T1-weighted MP2-RAGE images and multiple consecutive 23Na-MRI imaging images; Step 2, calculating the correlation slope b between the sodium ion concentration TSC and the corresponding signal intensity; Step 3, obtaining the cerebrospinal fluid structure mask; Step 4, obtaining the sodium ion concentration of multiple cerebrospinal fluids according to the cerebrospinal fluid structure mask and multiple continuous 23Na-MRI imaging images; Step 5: Fit the scanning time-sodium ion concentration curve f(t) and calculate the cerebrospinal fluid change rate.

2. The method for dynamic quantitative evaluation of cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging according to claim 1, characterized in that: The T1-weighted MP2-RAGE image and multiple consecutive 23Na-MRI imaging images are generated by the following steps: The data of multiple continuous scans of the brain using the 23Na-MRI imaging coil are collected to obtain multiple continuous 23Na-MRI imaging images, and the data of brain scans using the hydrogen proton imaging coil are collected to obtain T1-weighted MP2-RAGE images.

3. The method for dynamic quantitative evaluation of cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging according to claim 1, characterized in that: The step 2 comprises the following steps: Step 2.1, collecting scanning data of the test tubes with different sodium ion concentrations TSC in the 23Na-MRI imaging coil, obtaining the signal intensity value of each voxel of the test tubes with different sodium ion concentrations TSC, and calculating the average value of the voxel signal intensity of each test tube as the signal intensity corresponding to the sodium ion concentration; Step 2.2, construct a calculation formula for the linear correlation slope b between the sodium ion concentration TSC and the corresponding signal intensity and calculate the correlation slope b between the sodium ion concentration TSC and the corresponding signal intensity; the calculation formula for the correlation slope b between the sodium ion concentration TSC and the corresponding signal intensity is as follows: Among them, I i is the signal intensity of the test tube with the ith concentration; I m is the average signal intensity of all concentration test tubes; S i is the sodium ion concentration TSC of the test tube with the ith concentration; S m is the average value of the sodium ion concentration TSC of all test tubes with different concentrations, and D is the total number of concentration types.

4. The method for dynamic quantitative evaluation of cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging according to claim 1, characterized in that: The cerebrospinal fluid structure mask is generated by the following steps: The cerebrospinal fluid area is determined and outlined on the T1-weighted MP2-RAGE image obtained in step 1. The T1-weighted MP2-RAGE image is masked (MASK) according to the outlined result, and the outlined area is assigned a value of 1, and the remaining areas are assigned a value of 0 to obtain the cerebrospinal fluid structure mask.

5. The method for dynamic quantitative evaluation of cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging according to claim 3, characterized in that: The step 4 comprises the following steps: Step 4.1, superimposing the cerebrospinal fluid structure mask obtained in step 3 and the multiple continuous 23Na-MRI imaging images obtained in step 1 respectively to obtain the cerebrospinal fluid 23Na-MRI imaging image corresponding to each scan; Step 4.2, extracting the average signal intensity of each cerebrospinal fluid 23Na-MRI imaging image; Step 4.3: Calculate the sodium ion concentration (TSC) of the cerebrospinal fluid at the corresponding level during the nth scan based on the following formula: CSFn , TSC CSFn =I0+b×I CSFn Where n is the number of scans, b is the linear correlation slope between sodium ion concentration TSC and signal intensity; I0 is the average signal intensity of the background area; I CSFn It is the average signal intensity of the cerebrospinal fluid area at the corresponding level during the nth scan.

6. The method for dynamic quantitative evaluation of cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging according to claim 5, characterized in that: The step 5 comprises the following steps: Step 5.1, set the scanning time as the horizontal axis, the unit of the horizontal axis is the interval time between each scan, set the sodium ion concentration TSC as the vertical axis, and record the cerebrospinal fluid sodium ion concentration at the level corresponding to the nth scanning time obtained in step 4 as TSC CSFn , N is the total number of scans, and the following polynomial is constructed: TSC CSFn =a0+a1T1+a2T2+...+a n T n Among them, a0, a1, a2, ..., a n are all correlation coefficients; T1, T2, ..., T n is the scanning time from the 1st to the nth time, The least squares method is used to fit the above polynomials and determine the correlation coefficients a0, a1, a2, ..., a n The scan time-sodium ion concentration curve f(t) was obtained by fitting. Step 5.2: Calculate the scan time T based on the following formula: n The sodium concentration of cerebrospinal fluid at T n-1 The rate of change R CSFn , Among them, T n and T n-1 They are the nth scanning time and the n-1th scanning time respectively.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, each step of the method for dynamic quantitative evaluation of cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging according to any one of claims 1 to 6 is implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, each step of the method for dynamic quantitative evaluation of cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging according to any one of claims 1 to 6 is implemented.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, each step of the method for dynamic quantitative evaluation of cerebrospinal fluid based on sodium ion concentration magnetic resonance imaging according to any one of claims 1 to 6 is implemented.

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