WO2023070865A1 - Vascular reactivity evaluation method and apparatus, electronic device, and storage medium - Google Patents

Abstract

A vascular reactivity evaluation method and apparatus, an electronic device, and a storage medium. The method comprises: acquiring a first magnetic susceptibility-weighted image of a brain region of a target subject in a free-breathing state and a second magnetic susceptibility-weighted image in a breath-holding state (S110); determining a blood vessel distribution map of the brain region (S120); determining a first oxygen extraction fraction of a target blood vessel in the free-breathing state according to the first magnetic susceptibility-weighted image and the blood vessel distribution map (S130); determining a second oxygen extraction fraction of the target blood vessel in a breath-holding state according to the second magnetic susceptibility-weighted image and the blood vessel distribution map (S140); and determining an evaluation index of the vascular reactivity of the target blood vessel according to the first oxygen extraction fraction and the second oxygen extraction fraction of the target blood vessel, and evaluating the vascular reactivity of the target vessel on the basis of the evaluation index (S150), such that the vascular reactivity can be evaluated simply, quickly and accurately by means of the oxygen extraction fractions in the free-breathing state and in the breath-holding state.

Description

Method, device, electronic device and storage medium for evaluating vascular reactivity technical field

The embodiments of the present invention relate to the field of biomedical technology, and in particular to an evaluation method, device, electronic equipment and storage medium for vascular reactivity.

Background technique

Oxygen extraction fraction (OEF) is a parameter that reflects the demand and utilization of oxygen by brain tissue. Under physiological conditions, the distribution of OEF in the whole brain is relatively uniform. Under pathological conditions, OEF may increase or decrease to varying degrees. Current research focuses on quantitative estimation of fractional oxygen uptake and visualization of its distribution across the brain.

At present, the method of estimating oxygen uptake fraction by magnetic resonance is mainly based on the inversion of different magnetic susceptibility information of different oxygenation states of hemoglobin. Compared with oxyhemoglobin, deoxyhemoglobin is a strongly paramagnetic substance, and the T2* relaxation signal is significantly shortened under a magnetic field. Although the method of estimating the fraction of oxygen uptake by magnetic resonance imaging can achieve non-invasive quantitative measurement, the acquisition time of magnetic resonance is too long (2 minutes to 10 minutes), and the self-regulation function of blood vessels cannot be obtained during the single oxygen supply and consumption process of the body. Information; Although the method of inhaling different proportions of carbon dioxide and other gases can simulate the vascular response under different hypoxic conditions, it is only used in experimental research at present, and is subject to many limitations in clinical applicability.

Contents of the invention

Embodiments of the present invention provide a method, device, electronic device and storage medium for evaluating vascular reactivity, so as to complete the estimation of magnetic resonance oxygen uptake fraction in a short time and determine the effect of vascular reactivity.

In the first aspect, an embodiment of the present invention provides a method for evaluating vascular reactivity, the method comprising:

acquiring a first susceptibility-weighted imaging of a brain region of a target subject in a free-breathing state and a second susceptibility-weighted imaging of the target subject in a breath-holding state;

determining a vasculature map of the brain region;

determining a first oxygen uptake fraction of a target blood vessel in the brain region in a freely breathing state according to the first magnetic susceptibility weighted imaging and the blood vessel distribution map;

determining a second oxygen uptake fraction of a target blood vessel in the brain region in a breath-hold state according to the second susceptibility-weighted imaging and the blood vessel distribution map;

An evaluation index of the vascular reactivity of the target blood vessel is determined according to the first oxygen uptake fraction and the second oxygen uptake fraction of the target blood vessel, and the vascular reactivity of the target blood vessel is evaluated based on the evaluation index.

In the second aspect, the embodiment of the present invention also provides an evaluation device for vascular reactivity, which includes:

A susceptibility-weighted imaging acquisition module, configured to acquire a first susceptibility-weighted imaging of the brain region of the target subject in a free-breathing state and a second susceptibility-weighted imaging of the target subject in a breath-holding state;

A blood vessel distribution map determination module, configured to determine the blood vessel distribution map of the brain region;

A first oxygen uptake fraction determination module, configured to determine the first oxygen uptake fraction of the target blood vessel in the brain region in a freely breathing state according to the first magnetic susceptibility weighted imaging and the blood vessel distribution map;

A second oxygen uptake fraction determination module, configured to determine a second oxygen uptake fraction of the target blood vessel in the brain region in a breath-holding state according to the second susceptibility-weighted imaging and the blood vessel distribution map;

A vascular reactivity evaluation module, configured to determine an evaluation index of the vascular reactivity of the target blood vessel according to the first oxygen uptake fraction and the second oxygen uptake fraction of the target blood vessel, and evaluate the target blood vessel based on the evaluation index The vasoreactivity was evaluated.

In a third aspect, an embodiment of the present invention also provides an electronic device, the electronic device comprising:

one or more processors;

storage means for storing one or more programs,

When the one or more programs are executed by the one or more processors, the one or more processors implement the method for evaluating vascular reactivity provided by any embodiment of the present invention.

In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method for evaluating vascular reactivity provided by any embodiment of the present invention is implemented.

In the technical solution of this embodiment, the first magnetic susceptibility-weighted imaging of the brain region of the target subject in the state of free breathing and the second magnetic susceptibility-weighted imaging of the target subject in the state of holding the breath can be obtained, and different oxygen levels can be determined. Brain blood vessels are imaged in a metabolic environment, and the corresponding first quantitative magnetic susceptibility atlas and second quantitative magnetic susceptibility atlas can be further determined through the obtained first magnetic susceptibility weighted imaging and second magnetic susceptibility weighted imaging. determining a blood vessel distribution map of the brain region, determining a first oxygen uptake fraction of a target blood vessel in the brain region in a freely breathing state according to the first susceptibility-weighted imaging and the blood vessel distribution map; and according to the determined The second magnetic susceptibility weighted imaging and blood vessel distribution atlas determine the second oxygen uptake fraction of the target blood vessel in the brain region in the breath-holding state; it is used to determine the target blood vessel in the brain region in the free breathing state and In the breath-holding state, the parameters of the oxygen demand and utilization rate of the target blood vessel in the brain region of the target subject; finally, determine the An evaluation index of the vascular reactivity of the target blood vessel, evaluating the vascular reactivity of the target blood vessel based on the evaluation index. Used to determine the vascular responsiveness of the target blood vessel based on the first oxygen uptake fraction and the second oxygen uptake fraction. It solves the problem that there is no effective method for evaluating vascular reactivity at present, and achieves a simple, rapid and accurate evaluation of vascular reactivity through the oxygen uptake fraction in the free breathing state and the breath holding state, and can be applied to clinical applications. technical effect.

Description of drawings

In order to illustrate the technical solutions of the exemplary embodiments of the present invention more clearly, the following briefly introduces the drawings used in describing the embodiments. Apparently, the drawings introduced are only the drawings of a part of the embodiments to be described in the present invention, rather than all the drawings. Those of ordinary skill in the art can also obtain the Other attached drawings.

FIG. 1 is a schematic flowchart of a method for evaluating vascular reactivity provided by Embodiment 1 of the present invention;

Fig. 2 is a schematic flowchart of a method for evaluating vascular reactivity provided in Example 2 of the present invention;

Fig. 3 is a schematic diagram of the experimental process of a method for evaluating vascular reactivity provided in Example 2 of the present invention;

Fig. 4 is a result diagram of vascular reactivity oxygen uptake fraction in a method for evaluating vascular reactivity provided in Example 2 of the present invention;

Fig. 5 is a schematic structural view of an evaluation device for vascular reactivity provided by Embodiment 3 of the present invention;

FIG. 6 is a schematic structural diagram of an electronic device provided by Embodiment 4 of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, only some structures related to the present invention are shown in the drawings but not all structures.

In addition, it should be noted that, for the convenience of description, only parts related to the present invention are shown in the drawings but not all content. Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe various operations (or steps) as sequential processing, many of the operations may be performed in parallel, concurrently, or simultaneously. In addition, the order of operations can be rearranged. The process may be terminated when its operations are complete, but may also have additional steps not included in the figure. The processing may correspond to a method, function, procedure, subroutine, subroutine, or the like.

Embodiment one

FIG. 1 is a schematic flow chart of a method for evaluating vascular reactivity provided by Embodiment 1 of the present invention. This embodiment is applicable to the determination of vascular reactivity. The method can be performed by an evaluation device for vascular reactivity. The device can be implemented by software and/or hardware, and can be configured in a terminal and/or server to implement the method for evaluating vascular reactivity in the embodiment of the present invention.

As shown in Figure 1, the method of this embodiment may specifically include:

S110. Acquire a first susceptibility-weighted imaging of a brain region of a target subject in a state of free breathing and a second susceptibility-weighted imaging of the target subject in a state of holding a breath.

Susceptibility Weighted Imaging (SWI) is a new type of imaging technology that uses the difference in magnetic susceptibility of different tissues to generate image contrast.

Wherein, the target object may be understood as an object that is about to acquire magnetic susceptibility-weighted imaging of a brain region by using a magnetic resonance method. The brain region can be understood as the whole brain region of the target subject.

In the embodiment of the present invention, the first susceptibility-weighted imaging can be understood as the magnetic susceptibility-weighted imaging collected when the target object is in a free breathing (Free Breathing, FB) state, which can be denoted as SWI ₁ . The second susceptibility-weighted imaging can be understood as the susceptibility-weighted imaging collected when the target object is in a breath-hold (Breath-Hold, BH) state, which can be expressed as SWI ₂ .

Specifically, in order to avoid the impact of the instrument on the classification results, the data of all the target subjects participating in the study were scanned with the same type of Magnetic Resonance Imaging (MRI) instrument and the same scanning sequence on the head of the target subject in a resting state. scanning. Then, in the state of the target subject breathing freely, the first susceptibility-weighted imaging data SWI ₁ of the brain region of the target subject is collected. While the target subject is holding his breath, the second susceptibility-weighted imaging data SWI ₂ of the brain region of the target subject is collected.

Among them, vascular reactivity can be understood as the ability of blood vessels to shrink or relax under the action of various influencing factors, which can effectively reflect the ability of blood vessels to regulate.

Optionally, the brain data of the target subject is collected based on the SWI ₁ data as the reference data of the magnetic susceptibility of the brain region of the vascular reactivity. Optionally, based on the SWI ₂ data, brain region data of the target object are collected as vascular reactivity brain region magnetic susceptibility data.

Optionally, the time difference between the acquisition time of the first susceptibility-weighted imaging and the acquisition time of the second susceptibility-weighted imaging is within a preset difference range, and the first susceptibility-weighted imaging and the The parameters of the scanning sequence adopted by the second magnetic susceptibility weighted imaging are the same.

Specifically, the time difference between the acquisition time of the first susceptibility-weighted imaging and the acquisition time of the second susceptibility-weighted imaging is within the preset difference range, in other words, the acquisition time of the first susceptibility-weighted imaging and the second susceptibility-weighted imaging The smaller the time difference between acquisition times for weighted imaging, the better.

Specifically, the acquisition time of the first susceptibility-weighted imaging is relatively short, and considering the difference in the breath-hold time of the target object, the average maximum breath-hold time of the target object is used as the setting time of the first susceptibility-weighted imaging and the second susceptibility-weighted imaging. In the embodiment of the present invention, in order to ensure that the data in the free breathing state is accurate and not affected by breath-holding, the magnetic susceptibility-weighted imaging in the free-breathing state can be collected first, and then the magnetic susceptibility-weighted imaging in the breath-holding state can be collected. The advantage is that blood vessel data can be collected accurately when the collection interval is short. Since the susceptibility-weighted imaging in the free-breathing state is collected first, the acquisition time of the first susceptibility-weighted imaging can be set first, for example, the time in the free-breathing state of the target object is set within 30s, and then the breath-holding state is controlled The acquisition time of the second susceptibility-weighted imaging and the acquisition time of the first susceptibility-weighted imaging may be approximately the same, for example, the preset difference range may be set within ±2s.

The parameters of the scanning sequence used in the first susceptibility-weighted imaging and the second susceptibility-weighted imaging are the same, thus, the influence caused by the difference in acquisition equipment or the difference in acquisition parameters during the acquisition process of susceptibility-weighted imaging can be minimized .

S120. Determine the blood vessel distribution map of the brain region.

Among them, the map of blood vessel distribution can be understood as the map of the distribution position and shape of blood vessels in the brain region. Through the map of blood vessels, the situation of blood vessels can be clearly seen, such as the thickness of blood vessels, branches, distribution positions, and the relationship with each blood vessel. connection relationship. There are many methods that can be used to determine the blood vessel distribution map of the brain region, such as deep learning algorithm, multimodal fusion algorithm, image segmentation or morphological processing and other methods.

Specifically, taking the determination of the blood vessel distribution in the brain region based on the deep learning algorithm as an example, firstly perform magnetic resonance angiography on the brain region, and then preprocess the gray value of the obtained magnetic resonance angiography, according to the preset The region of interest is determined by the threshold, and then the blood vessel region in the brain region is extracted according to the region of interest. Divide the blood vessel area into multiple local images, select a fixed blood vessel area for labeling according to the 3DUNet network in the deep learning algorithm, and use this area as the base point to randomly select multiple local areas to obtain the local blood vessel segmentation results. Then all the local regions are stitched together to obtain the overall vascular distribution map.

Exemplarily, the image segmentation method can also be used to determine the blood vessel distribution map, mark the key points of the blood vessels in the magnetic resonance angiography, determine the geometric feature points of the blood vessels in the brain region, and then find out the matching feature point pairs, by matching The relationship between the feature point pairs in the brain area image is serialized and subtracted, and then the set of feature points in the serialized subtracted image is extracted, and the local position adjustment of the feature points of the edge of the blood vessel in the subtracted image is performed. Using the gray value, the feature points on the edge of the blood vessel are moved into the blood vessel, and then the image is segmented based on region growing and adaptive threshold to obtain the blood vessel distribution map of the brain region.

There are many methods for determining the blood vessel distribution map of the brain region, which are not limited and can be determined according to actual needs.

Optionally, the determining the blood vessel distribution map of the brain region includes: acquiring a third susceptibility-weighted imaging of the brain region of the target subject in a free-breathing state; determining the corresponding a third quantitative magnetic susceptibility atlas; determining a blood vessel distribution atlas of the brain region according to the prior knowledge template of the brain region, the third magnetic susceptibility weighted imaging, and the third quantitative magnetic susceptibility atlas.

Wherein, the acquisition time of the third magnetic susceptibility weighted imaging is longer than the acquisition time of the first magnetic susceptibility weighted imaging.

Among them, the prior knowledge template can be understood as knowledge information that can be known based on existing knowledge. In the embodiment of the present invention, each voxel in the brain region has a probability of occurrence of blood vessels, and the prior knowledge template can represent the magnetic susceptibility weighted Each voxel in the imaging is the probability template of the vein.

Specifically, according to the prior knowledge template of the brain region, the probability that each voxel of the brain tissue is a blood vessel can be known. The third susceptibility-weighted imaging acquired in the free-breathing state of the target object may be used to acquire whole-brain venous vessel segmentation based on the high-resolution data of the third susceptibility-weighted imaging. Then, the third quantitative magnetic susceptibility atlas is obtained by processing according to the third magnetic susceptibility weighted imaging, and further, the blood vessel distribution map of the brain region of the target object is determined according to the third quantitative magnetic susceptibility atlas, and the distribution of the whole brain blood vessel network can be obtained. Therefore, the Gaussian mixture weighted summation of the information of the prior knowledge template of the brain region, the third magnetic susceptibility weighted imaging and the third quantitative magnetic susceptibility map can be used to obtain the venous blood vessel distribution map of the brain region, The distribution of venous vessels in the brain region can be judged more accurately, which is more conducive to the complete segmentation of venous vessels.

Optionally, the determining the third quantitative magnetic susceptibility map corresponding to the third magnetic susceptibility weighted imaging includes: generating a brain mask image based on the original amplitude image of the third magnetic susceptibility weighted imaging; determining the The magnetic susceptibility weighted imaging of the brain area corresponding to the inner brain area in the third magnetic susceptibility weighted imaging; performing phase dephasing processing and background field removal processing on the original phase image of the magnetic susceptibility weighted imaging in the brain, to obtain The target phase image: calculate the magnetic susceptibility distribution of each voxel in the internal brain area according to the amplitude prior information of the brain mask image, the target phase image and the least square method, and reconstruct the third quantitative magnetic susceptibility map.

Wherein, the mask image can be understood as an image filtering template, and the mask image can usually be constructed by using a morphological method to extract the ROI of the brain region of the target object. Susceptibility-weighted imaging can be understood as collecting data based on gradient echo sequences, and after special data processing and image reconstruction, it forms a magnetic resonance imaging technique that is sensitive to material susceptibility. In the embodiment of the present invention, the susceptibility-weighted imaging in the brain can be understood as the data obtained by performing magnetic susceptibility-weighted imaging on the brain region of the target subject. The original phase image can be understood as the use of magnetic resonance imaging technology to scan the brain region of the target subject, and the obtained phase data difference of different protons forms an image contrast magnetic resonance image, which can be used to reflect the original state of different protons in the relaxation process. phase information. The processing method for dephasing may be linear or non-linear, for example, a least squares dephasing processing method or a weighted least squares dephasing processing method may be used.

Specifically, in the process of quantitative magnetic susceptibility imaging, the collected data includes two parts of information, the inner brain area and the outer brain area. It is necessary to reserve the inner brain area as the region of interest, and finally present the region of interest in the quantitative magnetic susceptibility results. Therefore, in the process of quantifying magnetic susceptibility, it is necessary to filter non-interest regions of the brain region of the target object. There are many ways to determine the region of interest in the brain region of the target object, for example, image segmentation based on gray histogram threshold, region expansion morphology method, image segmentation based on amplitude, image segmentation based on edge, image segmentation based on wavelet transform Segmentation, image segmentation based on region growing, and image segmentation based on specific theories. These image segmentation methods can be used to divide the region of interest in the image. When determining the region of interest in the image, the brain mask image can be generated based on the original amplitude image of the third magnetic susceptibility weighted imaging in the free breathing state of the target object, and the brain magnetization corresponding to the inner brain region of the brain region can be obtained Rate-weighted imaging filters out areas of non-interest, such as the skull, to provide brain boundary information for better quality image data in the next step.

According to the constructed brain mask image, the susceptibility-weighted imaging corresponding to the inner brain area can be determined, and the original phase image of the intra-brain susceptibility-weighted imaging is dephased and the background field is removed to obtain the target phase image. The prior probability of magnetic susceptibility and the least square method are used to solve the quantitative magnetic susceptibility of the image information in the brain, and reconstruct the third quantitative magnetic susceptibility map.

Similarly, in the state of the target subject breathing freely, perform the same operation based on the third magnetic susceptibility weighted image to reconstruct the third quantitative magnetic susceptibility map; Operation, reconstructs the second quantitative susceptibility map.

Optionally, performing phase dephasing processing on the original phase image of the intracerebral susceptibility-weighted imaging includes: performing dephasing according to the phase information of multiple voxels and the scan time of the original phase image of the intracerebral susceptibility-weighted imaging. Regional phase winding estimation, based on the estimation result, reversely solves the aliasing phase, and obtains the real phase information of the magnetic susceptibility weighted imaging in the brain.

Specifically, due to the long scanning time of the brain region by magnetic resonance, the phase image of the magnetic susceptibility weighted imaging will have the phenomenon of image phase aliasing, so it is necessary to dephase the image and analyze the image into time information and spatial information . Then combine the phase information of multiple voxels and the scanning time to estimate the regional phase winding, and inversely solve the aliasing phase to obtain the real phase information. Optionally, when performing phase dephasing processing on the image, in the phase image weighted by magnetic susceptibility, the area with less phase aliasing starts to be processed, and the area with more aliasing is gradually processed.

S130. Determine a first oxygen uptake fraction of a target blood vessel in the brain region in a freely breathing state according to the first magnetic susceptibility weighted imaging and the blood vessel distribution map.

Wherein, the target blood vessel can be understood as a vein blood vessel in the brain region of the target object. The acquisition methods of target blood vessels include but are not limited to methods such as image segmentation, erosion and expansion algorithm, seed growth method, area filling method, mathematical morphology method, watershed method or pattern recognition method. The first oxygen uptake fraction can be understood as a parameter of the oxygen demand and utilization rate of the target blood vessel in the brain region of the target subject in a free breathing state. There are many ways to determine fractional oxygen uptake, for example, non-invasive fractional oxygen uptake measurement based on asymmetric spin echo fast imaging technology, quantitative measurement by T2 relaxation spin labeling imaging technique, and simulated gas-free Task vascular response measurement method, through intermittent breath-holding state and free breathing state, measure the ratio of oxygenated hemoglobin and deoxygenated hemoglobin in the target blood vessel, and then calculate the process of breath-holding state and free breathing state by combining the time of state change process oxygen uptake fraction.

Specifically, the third susceptibility-weighted imaging of the brain region of the target subject in a free-breathing state can be obtained, and the third quantitative susceptibility atlas corresponding to the third susceptibility-weighted imaging can be determined. For the third susceptibility-weighted imaging and For the acquisition of the first susceptibility-weighted imaging, the same type of magnetic resonance instrument and the same scanning sequence are used to scan the brain region of the target subject. The number of scans is not limited, and can be one time or multiple times. When acquiring the first susceptibility-weighted imaging and the third susceptibility-weighted imaging, in order to ensure the validity of the collected data and the accuracy of the calculation of the oxygen uptake fraction, the acquisition time of the third susceptibility-weighted imaging can be longer than the first Acquisition time for susceptibility-weighted imaging. Compared with the acquisition time of the first susceptibility-weighted imaging, the acquisition time of the third susceptibility-weighted imaging is longer, for example, the acquisition time can be set to 2-10 minutes.

Under the free breathing state of the target subject, the brain region of the target subject is scanned by the magnetic resonance instrument at rest, and the susceptibility difference between different tissues is used to scan the brain region of the target subject by 3D gradient echo sequence, and On this basis, special data processing and image reconstruction are performed on the magnetic resonance scanning images to obtain the first magnetic susceptibility weighted imaging and the third magnetic susceptibility weighted imaging. According to the first magnetic susceptibility weighted imaging and the blood vessel distribution map, and the corresponding tissue magnetic susceptibility characteristics of different tissues, the first oxygen uptake fraction of the target blood vessel in a free breathing state is determined.

S140. Determine a second oxygen uptake fraction of a target blood vessel in the brain region in a breath-holding state according to the second magnetic susceptibility weighted imaging and the blood vessel distribution map.

Wherein, the image acquisition parameters of the second susceptibility-weighted imaging are the same as those of the first susceptibility-weighted imaging, and the same type of magnetic resonance instrument, the same scanning sequence and the same scanning parameters are used, which are different from the first susceptibility-weighted imaging, and the second Susceptibility-weighted imaging is acquired by scanning the brain region of the target subject while the target subject is holding his breath. The second oxygen uptake score can be understood as a parameter of the oxygen demand and utilization rate of the target subject in a breath-holding state.

Specifically, when the target subject is holding his breath, the brain region of the target subject is scanned by a magnetic resonance instrument at rest, and the difference in susceptibility between different tissues is used to scan the brain region of the target subject using a 3D gradient echo sequence. The region is scanned, and on this basis, special data processing and image reconstruction are performed on the magnetic resonance scanning image to obtain a second magnetic susceptibility weighted imaging, and then the target of the brain region is determined according to the second magnetic susceptibility weighted imaging and the blood vessel distribution map Fractional second oxygen uptake by vessels in the breath-hold state.

S150. Determine the evaluation index of the vascular reactivity of the target blood vessel according to the first oxygen uptake fraction and the second oxygen uptake fraction of the target blood vessel, and evaluate the vascular reactivity of the target blood vessel based on the evaluation index .

Among them, vascular reactivity can be understood as the ability of blood vessels to shrink or relax under the action of various vascular influencing factors, which can effectively reflect the ability of vascular regulation. The evaluation index of vascular reactivity can include the inhalation of carbon dioxide by the target blood vessel in the two states of free breathing state and breath-holding state, test the oxygen uptake fraction of the target blood vessel in different states, and use the difference as the vascular response A specific evaluation index, and evaluate the vascular reactivity of the target blood vessel based on the evaluation index.

For example, after the target subject inhales carbon dioxide in a state of free breathing, the flow velocity in the target blood vessel becomes significantly faster; in the state of hyperventilation of the target subject, the average blood flow velocity in the target vessel slows down significantly, and after hyperventilation 20～ After 30s, the blood flow velocity in the target blood vessel gradually stabilized without any obvious change; when the target subject held his breath, the blood flow velocity in the target blood vessel increased significantly with the increase of the breath-holding time of the target subject, while in the breath-holding state of the target subject After holding the breath for more than 30 seconds, the blood flow rate in the target blood vessel gradually stabilized. Therefore, the increase rate of blood flow velocity in the target blood vessel or the breath-hold index in the three states can be used as the evaluation index of vascular reactivity. The most convenient indicator of the vasoreactivity of the target vessel.

Specifically, according to the first susceptibility-weighted imaging and the third susceptibility-weighted imaging, the first oxygen uptake fraction of the target blood vessel in the brain region in a free-breathing state is determined. A second oxygen uptake fraction of the target blood vessel in the brain region in a breath-hold state is determined according to the second susceptibility-weighted imaging and the third susceptibility-weighted imaging. An evaluation index of the vascular reactivity of the target blood vessel is determined based on the first oxygen uptake fraction and the second oxygen uptake fraction of the target blood vessel, and the vascular reactivity of the target blood vessel is evaluated based on the evaluation index.

Optionally, the determining the evaluation index of the vascular reactivity of the target blood vessel according to the first oxygen uptake fraction and the second oxygen uptake fraction of the target blood vessel includes: for each voxel of the target blood vessel, calculating the The score difference between the first oxygen uptake fraction and the second oxygen uptake fraction is determined according to the score difference to determine the evaluation index of the blood vessel reactivity of the target blood vessel.

Among them, a voxel in a blood vessel can be understood as a three-dimensional unit represented by a pixel in an image, and can also be understood as the smallest geometric unit that can be distinguished in magnetic resonance effects, and a voxel contains at least one blood cell.

Specifically, the first oxygen uptake fraction and the second oxygen uptake fraction in each voxel can be calculated for each voxel in the target blood vessel in the magnetic resonance image, and then the ratio of the two oxygen uptake fractions corresponding to each voxel can be calculated The score difference, the evaluation index of the vascular reactivity of the target blood vessel can be determined according to the score difference corresponding to each voxel. For example, it may be specifically to calculate the fractional differences between the first oxygen uptake fraction and the second oxygen uptake fraction of multiple voxels in the target blood vessel respectively, and then perform a weighted average on the corresponding fractional differences among the multiple voxels, and average the The score difference of the target vessel was used as an evaluation index of the vascular reactivity of the target vessel. It may also be that the first oxygen uptake fractions of multiple voxels in the target blood vessel are weighted and summed and then averaged to obtain the first oxygen uptake fraction average, and the second oxygen uptake fractions of multiple voxels in the target blood vessel The uptake scores are weighted and summed and then averaged to obtain the average value of the second oxygen uptake score, and then the score difference between the first oxygen uptake score mean value and the second oxygen uptake score mean value is used as the evaluation index of the vascular reactivity of the target blood vessel .

Optionally, the first susceptibility-weighted imaging, the second susceptibility-weighted imaging and the third susceptibility-weighted imaging are registered.

Specifically, registration can be understood as registering the first susceptibility-weighted imaging, the second susceptibility-weighted imaging, and the third susceptibility-weighted imaging, so as to correct the pixels representing the same tissue in the three sets of data to The same location to meet the needs of data analysis. For example, the angle of rotation of the target can be obtained by susceptibility-weighted imaging.

For example, with SWI ₂ as a reference, standard feature statistics and linear fitting are performed on SWI ₁ and SWI ₂ , and the two sets of data are corrected to the same position. Taking SWI ₂ as a reference, constrain the mutual information entropy of gray values between SWI ₃ and SWI ₂ , and correct the two sets of data to the same position.

In the technical solution of this embodiment, the first magnetic susceptibility-weighted imaging of the brain region of the target object in the state of free breathing and the second magnetic susceptibility-weighted imaging of the target object in the state of holding the breath are obtained, through the obtained first The magnetic susceptibility weighted imaging and the second magnetic susceptibility weighted imaging can further determine the corresponding first quantitative magnetic susceptibility map and the second quantitative magnetic susceptibility map. determining a blood vessel distribution map of the brain region, determining a first oxygen uptake fraction of a target blood vessel in the brain region in a freely breathing state according to the first susceptibility-weighted imaging and the blood vessel distribution map; and according to the determined The second magnetic susceptibility weighted imaging and blood vessel distribution atlas determine the second oxygen uptake fraction of the target blood vessel in the brain region in the breath-holding state; it is used to determine the target blood vessel in the brain region in the free breathing state and In the breath-holding state, the parameters of the oxygen demand and utilization rate of the target blood vessel in the brain region of the target subject; finally, determine the An evaluation index of the vascular reactivity of the target blood vessel, evaluating the vascular reactivity of the target blood vessel based on the evaluation index. Used to determine the vascular responsiveness of the target blood vessel based on the first oxygen uptake fraction and the second oxygen uptake fraction. It solves the problem that there is no effective method for evaluating vascular reactivity at present, and achieves a simple, rapid and accurate evaluation of vascular reactivity through the oxygen uptake fraction in the free breathing state and the breath holding state, and can be applied to clinical applications. technical effect.

Embodiment two

Fig. 2 is a schematic flow chart of the evaluation method of vascular reactivity provided by Embodiment 2 of the present invention. This embodiment is based on any optional technical solution in the embodiment of the present invention. Optionally, the A susceptibility-weighted imaging and blood vessel distribution atlas to determine a first oxygen uptake fraction of the brain region in a free-breathing state, comprising: determining a first quantitative susceptibility atlas corresponding to the first susceptibility-weighted imaging; For each voxel of the target blood vessel in the blood vessel distribution atlas, calculate the quantitative magnetic susceptibility of each voxel in the first quantitative magnetic susceptibility atlas and the relationship between the quantitative magnetic susceptibility and the oxygen uptake fraction established in advance. The first fraction of oxygen uptake for each voxel in the target vessel.

Specifically, the method of this embodiment may include:

S210. Acquire a first susceptibility-weighted imaging of a brain region of a target subject in a state of free breathing and a second susceptibility-weighted imaging of the target subject in a state of holding a breath.

S220. Determine the blood vessel distribution map of the brain region.

S230. Determine a first quantitative magnetic susceptibility map corresponding to the first magnetic susceptibility weighted imaging.

Among them, quantitative magnetic susceptibility atlas can be understood as a map reconstructed by magnetic susceptibility inversion technology. Quantitative magnetic susceptibility imaging is a technique used in magnetic resonance technology to quantitatively measure the magnetic susceptibility characteristics of tissues, which can analyze changes in blood oxygen saturation in tissues The resulting magnetic susceptibility can be effectively quantified. The first quantitative magnetic susceptibility spectrum can be understood as the first quantitative magnetic susceptibility spectrum corresponding to the first magnetic susceptibility weighted imaging of the target object in a free-breathing state collected by quantitative magnetization imaging technology.

Specifically, the first quantitative magnetic susceptibility calculation is performed on the brain region of the target subject in a free breathing state, and the first quantitative magnetic susceptibility atlas corresponding to the first magnetic susceptibility weighted imaging is obtained.

Optionally, the dephasing and background field removal processing on the original phase image of the susceptibility-weighted imaging of the brain includes: a unit dipole field and an arbitrary background field based on the internal brain region of the brain region The feature that the quadrature product of the unit dipole field is less than or equal to the preset threshold value is used to remove the background field of the original phase image of the susceptibility-weighted imaging in the brain.

Wherein, in other words, it may be determined by a preset threshold whether the orthogonal product of the unit dipole field in the brain region and any background field unit dipole field is less than or equal to the preset threshold. Exemplarily, the The preset threshold may be 0 or a value close to 0. The background field can be understood as being caused by the magnetization source outside the region of interest and the inhomogeneity of the main magnetic field, and the existence of the background field will affect the calculation of the magnetic susceptibility of the region of interest, so before calculating the magnetic susceptibility, it is necessary to filter out the background field components .

Specifically, in the embodiment of the present invention, the method of dipole field projection is used to remove the background field. The characteristic that the intersection product is close to 0 removes the background field and reduces the influence of the background field on the region of interest. Wherein, the method of judging that it is close to 0 may be whether the orthogonal product of the dipole background field of the non-interest region and the local dipole field of the interest region in the region of interest is within a preset error range. In other words, the difference between the quadrature product and 0 is within a preset error range.

S240. For each voxel of the target blood vessel in the blood vessel distribution map, according to the quantitative magnetic susceptibility of each voxel in the first quantitative magnetic susceptibility map and the relationship between the quantitative magnetic susceptibility and the oxygen uptake fraction established in advance , calculating the first oxygen uptake fraction of each voxel in the target blood vessel.

Specifically, after determining the blood vessel distribution map according to the prior knowledge template of the brain region, the third magnetic susceptibility weighted imaging, and the third quantitative magnetic susceptibility map, for each voxel of the blood vessel in the blood vessel distribution map, according to each voxel in the quantitative magnetic susceptibility map The quantitative magnetic susceptibility of the voxel and the pre-established relationship between the quantitative magnetic susceptibility and the oxygen uptake fraction are used to calculate the first oxygen uptake fraction of each voxel in the target blood vessel.

Optionally, the relationship between the quantitative magnetic susceptibility and the oxygen uptake fraction is determined based on the following formula:

Wherein, OEF is the oxygen uptake fraction of the voxel; Δχvein _-CSF = _χvein - _χCSF , _χvein is the quantitative magnetic susceptibility of the venous vessels in the quantitative magnetic susceptibility atlas, and _χCSF is the cerebrospinal fluid in the anterior region of the lateral ventricle Quantitative magnetic susceptibility; Δχ _vein-CSF represents the difference in magnetic susceptibility between venous blood vessels and cerebrospinal fluid; Δχ _deoxy is the difference in magnetic susceptibility between oxygenated and deoxygenated red blood cells per hematocrit; Δχ _oxy-CSF = χ _oxy -χ _CSF , Δχ _oxy-CSF is the magnetic susceptibility difference between oxygenated red blood cells and cerebrospinal fluid; χ _oxy is the magnetic susceptibility of oxygenated red blood cells; Hct is the hematocrit; pv is the correction parameter for the partial volume effect of the acquisition voxel.

It should be noted that, when calculating the first oxygen uptake fraction, _χvein is the quantitative magnetic susceptibility of the venous vessels in the first quantitative magnetic susceptibility map; when calculating the second oxygen uptake fraction, _xvein is the second quantitative susceptibility Quantitative magnetic susceptibility of venous blood vessels in susceptibility atlas.

S250. Determine a second oxygen uptake fraction of a target blood vessel in the brain region in a state of holding a breath according to the second magnetic susceptibility weighted imaging and the blood vessel distribution map.

Similarly, the second quantitative magnetic susceptibility atlas corresponding to the second magnetic susceptibility weighted imaging can be determined first, and then for each voxel of the target blood vessel in the blood vessel distribution atlas, according to each voxel in the second quantitative magnetic susceptibility atlas The second oxygen uptake fraction of each voxel in the target blood vessel is calculated based on the quantitative magnetic susceptibility of the voxel and the pre-established relationship between the quantitative magnetic susceptibility and the oxygen uptake fraction.

Specifically, the second quantitative magnetic susceptibility solution may be performed on the brain region of the target subject in a breath-holding state to obtain a second quantitative magnetic susceptibility atlas corresponding to the second magnetic susceptibility weighted imaging.

Wherein, the specific manner of determining the second quantitative magnetic susceptibility spectrum corresponding to the second magnetic susceptibility weighted imaging may be the same as the manner of determining the first quantitative magnetic susceptibility spectrum. The relationship between the quantitative magnetic susceptibility and the oxygen uptake fraction can be determined based on the aforementioned formula, and will not be repeated here.

S260. Determine the evaluation index of the vascular reactivity of the target blood vessel according to the first oxygen uptake fraction and the second oxygen uptake fraction of the target blood vessel, and evaluate the vascular reactivity of the target blood vessel based on the evaluation index .

Exemplarily, Embodiment 2 of the present invention provides an experimental method of a method for determining vascular reactivity. The specific steps and results of the experiment are as follows:

1. MRI acquisition

(1) Acquiring magnetic resonance data of the head of the target subject. It is required that the target object does not carry metal in the whole body, and does not have claustrophobia;

(2) Data acquisition: Siemens 3.0T magnetic resonance imaging system and 32-channel phased array head coil were used to collect the three susceptibility-weighted imaging SWI data of two healthy target subjects, which were: the first target subject in the free breathing state Three susceptibility-weighted imaging SWI ₃ , the first susceptibility-weighted imaging SWI ₁ of the target object in the free-breathing state, and the second magnetic susceptibility-weighted imaging SWI ₂ of the target object in the breath-holding state, and the experiment was repeated once.

As shown in FIG. 3 , FIG. 3 is a schematic diagram of the experimental process of a method for evaluating vascular reactivity provided by Embodiment 2 of the present invention.

Among them, the main imaging parameters of the third susceptibility-weighted imaging SWI ₃ of the target object in the free-breathing state are TR/TE ₁ , specifically 60/6.8ms, ΔTE=6.8ms, 7 echoes, FA of 15°, matrix=320×240, the size of each voxel is 0.75mm×0.75mm×2mm, and the acquisition time is 4 minutes; the main imaging parameters of the first susceptibility-weighted imaging SWI ₁ sum of the target object in the free breathing state are TR/TE, Specifically, it is 18/12ms, and the FA is 15°; the main imaging parameters of the second susceptibility-weighted imaging SWI ₂ of the target object in the breath-holding state are the same as those of the first susceptibility-weighted imaging, and are also TR/ TE, specifically 18/12ms, FA 15°, matrix=192×144, voxel size 1.2mm×1.2mm×5mm. The acquisition time of the first susceptibility-weighted imaging and the second susceptibility-weighted imaging is the same, and the acquisition time is 18s.

Among them, TR represents the repetition time, that is, the time required for the pulse sequence to execute once; TE represents the echo time, that is, the time required from the first radio frequency pulse to the generation of the echo signal; FA represents the flip angle; matrix represents a matrix Size, here can represent the number of pixels in each voxel in susceptibility-weighted imaging.

2. Data processing

Based on the phase map of the susceptibility-weighted imaging (SWI) data, the Bayesian regularization algorithm is used to reconstruct the quantitative susceptibility map (Quantitative Susceptibility mapping, QSM), and the susceptibility-weighted imaging (SWI) and quantitative magnetization based on the prior template and individual data Quantitative Mapping (QSM) to extract the venous vascular network of the brain region of the target subject. Changes in vascular reactivity (OEF) were calculated using the mathematical relationship between quantitative susceptibility galaxies and vascular reactivity (OEF) from the quantitative susceptibility map QSM map.

The calculation formula of OEF is as follows:

Wherein, OEF is the oxygen uptake fraction of the voxel; Δχvein _-CSF = _χvein - _χCSF , _χvein is the quantitative magnetic susceptibility of the venous vessels in the quantitative magnetic susceptibility atlas, and _χCSF is the cerebrospinal fluid in the anterior region of the lateral ventricle Quantitative magnetic susceptibility; Δχ _vein-CSF represents the difference in magnetic susceptibility between venous blood vessels and cerebrospinal fluid; Δχ _deoxy is the difference in magnetic susceptibility between oxygenated and deoxygenated red blood cells per hematocrit; Δχ _oxy-CSF = χ _oxy -χ _CSF , Δχ _oxy-CSF is the magnetic susceptibility difference between oxygenated red blood cells and cerebrospinal fluid; χ _oxy is the magnetic susceptibility of oxygenated red blood cells; Hct is the hematocrit; pv is the correction parameter for the partial volume effect of the acquisition voxel.

As shown in FIG. 4 , FIG. 4 is a result graph of vascular reactivity oxygen uptake fraction in a method for evaluating vascular reactivity provided in Example 2 of the present invention. The statistical method of paired T-test was used to evaluate the difference of vascular reactivity (OEF) between the groups in the free-breathing state (Free Breath, FB) and the breath-holding state (breath-hold, BH). The OEF between the two groups was p<0.05, and the vasoreactive OEF under breath-hold was 8.9% higher than the resting OEF on average.

The experiments described above demonstrate the feasibility of the measurement of vasoreactive fractional oxygen uptake.

It can be understood that the "first", "second" or "third" in the embodiments of the present invention are only used to distinguish different susceptibility-weighted imaging or oxygen uptake fractions, not for magnetic susceptibility-weighted imaging or oxygen uptake fractions The order or size etc. are limited.

In the technical solution of this embodiment, the first magnetic susceptibility-weighted imaging of the brain region of the target subject in the state of free breathing and the second magnetic susceptibility-weighted imaging of the target subject in the state of holding the breath can be obtained, and different oxygen levels can be determined. Brain blood vessels are imaged in a metabolic environment, and the corresponding first quantitative magnetic susceptibility atlas and second quantitative magnetic susceptibility atlas can be further determined through the obtained first magnetic susceptibility weighted imaging and second magnetic susceptibility weighted imaging. determining a blood vessel distribution map of the brain region, determining a first oxygen uptake fraction of a target blood vessel in the brain region in a freely breathing state according to the first susceptibility-weighted imaging and the blood vessel distribution map; and according to the determined The second magnetic susceptibility weighted imaging and blood vessel distribution atlas determine the second oxygen uptake fraction of the target blood vessel in the brain region in the breath-holding state; it is used to determine the target blood vessel in the brain region in the free breathing state and In the breath-holding state, the parameters of the oxygen demand and utilization rate of the target blood vessel in the brain region of the target subject; finally, determine the An evaluation index of the vascular reactivity of the target blood vessel, evaluating the vascular reactivity of the target blood vessel based on the evaluation index. Used to determine the vascular responsiveness of the target blood vessel based on the first oxygen uptake fraction and the second oxygen uptake fraction. It solves the problem that there is no effective method for evaluating vascular reactivity at present, and achieves a simple, rapid and accurate evaluation of vascular reactivity through the oxygen uptake fraction in the free breathing state and the breath holding state, and can be applied to clinical applications. technical effect.

Embodiment Three

Fig. 5 is a schematic structural diagram of an evaluation device for vascular reactivity provided in Embodiment 3 of the present invention. The evaluation device for vascular reactivity provided in this embodiment can be implemented by software and/or hardware, and can be configured in a terminal and/or server In order to realize the evaluation method of vascular reactivity in the embodiment of the present invention. The device may specifically include: a magnetic susceptibility weighted imaging acquisition module 510 , a blood vessel distribution map determination module 520 , a first oxygen uptake fraction determination module 530 , a vascular reactivity evaluation module 540 and a vascular reactivity evaluation module 550 .

Wherein, the susceptibility-weighted imaging acquisition module 510 is configured to acquire the first susceptibility-weighted imaging of the brain region of the target object in the state of free breathing and the second susceptibility-weighted imaging of the target object in the state of holding the breath;

A blood vessel distribution map determination module 520, configured to determine the blood vessel distribution map of the brain region;

A first oxygen uptake fraction determining module 530, configured to determine a first oxygen uptake fraction of the target blood vessel in the brain region in a freely breathing state according to the first magnetic susceptibility weighted imaging and the blood vessel distribution map;

The second oxygen uptake fraction determination module 540 is configured to determine the second oxygen uptake fraction of the target blood vessel in the brain region in a breath-holding state according to the second magnetic susceptibility weighted imaging and the blood vessel distribution map;

The vascular reactivity evaluation module 550 is configured to determine an evaluation index of the vascular reactivity of the target blood vessel according to the first oxygen uptake fraction and the second oxygen uptake fraction of the target blood vessel, and evaluate the target blood vessel based on the evaluation index. The vasoreactivity of blood vessels was evaluated.

In the technical solution of this embodiment, the first magnetic susceptibility-weighted imaging of the brain region of the target subject in the state of free breathing and the second magnetic susceptibility-weighted imaging of the target subject in the state of holding the breath can be obtained, and different oxygen levels can be determined. Brain blood vessels are imaged in a metabolic environment, and the corresponding first quantitative magnetic susceptibility atlas and second quantitative magnetic susceptibility atlas can be further determined through the obtained first magnetic susceptibility weighted imaging and second magnetic susceptibility weighted imaging. determining a blood vessel distribution map of the brain region, determining a first oxygen uptake fraction of a target blood vessel in the brain region in a freely breathing state according to the first susceptibility-weighted imaging and the blood vessel distribution map; and according to the determined The second magnetic susceptibility weighted imaging and blood vessel distribution atlas determine the second oxygen uptake fraction of the target blood vessel in the brain region in the breath-holding state; it is used to determine the target blood vessel in the brain region in the free breathing state and In the breath-holding state, the parameters of the oxygen demand and utilization rate of the target blood vessel in the brain region of the target subject; finally, determine the An evaluation index of the vascular reactivity of the target blood vessel, evaluating the vascular reactivity of the target blood vessel based on the evaluation index. Used to determine the vascular responsiveness of the target blood vessel based on the first oxygen uptake fraction and the second oxygen uptake fraction. It solves the problem that there is no effective method for evaluating vascular reactivity at present, and achieves a simple, rapid and accurate evaluation of vascular reactivity through the oxygen uptake fraction in the free breathing state and the breath holding state, and can be applied to clinical applications. technical effect.

On the basis of any optional technical solution in the embodiments of the present invention, optionally, the blood vessel distribution map determination module specifically includes:

The third susceptibility-weighted imaging acquisition submodule is used to acquire the third magnetic susceptibility-weighted imaging of the brain region of the target subject in a free-breathing state, wherein the acquisition time of the third magnetic susceptibility-weighted imaging is longer than the first Acquisition time for susceptibility-weighted imaging;

A third quantitative magnetic susceptibility spectrum determination submodule, configured to determine a third quantitative magnetic susceptibility spectrum corresponding to the third magnetic susceptibility weighted imaging;

The blood vessel distribution map determination submodule is configured to determine the blood vessel distribution map of the brain region according to the prior knowledge template of the brain region, the third magnetic susceptibility weighted imaging and the third quantitative magnetic susceptibility map.

On the basis of any optional technical solution in the embodiments of the present invention, optionally, the first oxygen uptake fraction determination module specifically includes: a quantitative magnetic susceptibility map determination submodule, a blood vessel distribution map determination submodule, and an oxygen uptake fraction Compute submodule.

Wherein, the first quantitative magnetic susceptibility map determination submodule is used to determine the first quantitative magnetic susceptibility map corresponding to the first magnetic susceptibility weighted imaging;

The oxygen uptake fraction calculation submodule is used for each voxel of the target blood vessel in the blood vessel distribution map, according to the quantitative magnetic susceptibility of each voxel in the second quantitative magnetic susceptibility map and the pre-established quantitative magnetic susceptibility and oxygen uptake The relationship between the fractions is used to calculate the first fraction of oxygen uptake for each voxel within the target blood vessel.

On the basis of any optional technical solution in the embodiments of the present invention, optionally, the third quantitative magnetic susceptibility map determination submodule specifically includes: a mask image generation unit, a magnetic susceptibility weighted imaging determination unit, a target phase An image acquisition unit and a quantitative magnetic susceptibility map reconstruction unit.

Wherein, a mask image generating unit is configured to generate a brain mask image based on the original amplitude image of the third magnetic susceptibility weighted imaging;

A susceptibility-weighted imaging determination unit, configured to determine the intracerebral susceptibility-weighted imaging corresponding to the inner brain area in the brain region of the third susceptibility-weighted imaging;

A target phase image acquisition unit, configured to perform dephasing processing and background field removal processing on the original phase image of the intracerebral magnetic susceptibility weighted imaging to obtain the target phase image;

The quantitative magnetic susceptibility atlas reconstruction unit is used to calculate the magnetic susceptibility distribution of each voxel in the internal brain region according to the amplitude prior information of the brain mask image, the target phase image and the least squares method, and reconstruct the first fixed magnetic susceptibility Quantitative magnetic susceptibility spectrum.

On the basis of any optional technical solution in the embodiments of the present invention, optionally, the quantitative magnetic susceptibility atlas reconstruction unit is configured to weight the phases of multiple voxels of the original phase image of the brain magnetic susceptibility weighted imaging Information and scan time are used to estimate the regional phase winding, and based on the estimated result, the aliasing phase is reversely solved to obtain the real phase information of the susceptibility-weighted imaging in the brain.

On the basis of any optional technical solution in the embodiments of the present invention, optionally, the quantitative magnetic susceptibility map reconstruction unit is configured to use the brain internal area unit dipole field and any background field based on the brain area If the quadrature product of the unit dipole field is less than a preset threshold, the background field of the original phase image of the susceptibility-weighted imaging in the brain is removed.

On the basis of any optional technical solution in the embodiments of the present invention, optionally, the relationship between the quantitative magnetic susceptibility and the oxygen uptake fraction is determined based on the following formula:

Wherein, OEF is the oxygen uptake fraction of the voxel; Δχvein _-CSF = _χvein - _χCSF , _χvein is the quantitative magnetic susceptibility of the venous vessels in the quantitative magnetic susceptibility atlas, and _χCSF is the cerebrospinal fluid in the anterior region of the lateral ventricle Quantitative magnetic susceptibility; Δχ _vein-CSF represents the difference in magnetic susceptibility between venous blood vessels and cerebrospinal fluid; Δχ _deoxy is the difference in magnetic susceptibility between oxygenated and deoxygenated red blood cells per hematocrit; Δχ _oxy-CSF = χ _oxy -χ _CSF , Δχ _oxy-CSF is the magnetic susceptibility difference between oxygenated red blood cells and cerebrospinal fluid; χ _oxy is the magnetic susceptibility of oxygenated red blood cells; Hct is the hematocrit; pv is the correction parameter for the collection voxel partial volume effect.

On the basis of any optional technical solution in the embodiments of the present invention, optionally, the vascular reactivity evaluation module is used for:

For each voxel of the target blood vessel, a score difference between the first oxygen uptake fraction and the second oxygen uptake score is calculated, and an evaluation index of vascular reactivity of the target blood vessel is determined according to the score difference.

On the basis of any optional technical solution in the embodiments of the present invention, optionally, the acquisition time of the third magnetic susceptibility weighted imaging is longer than the acquisition time of the first magnetic susceptibility weighted imaging, and the first magnetic susceptibility weighted imaging The time difference between the acquisition time of the weighted imaging and the acquisition time of the second susceptibility-weighted imaging is within a preset difference range, and the scanning adopted by the first susceptibility-weighted imaging and the second susceptibility-weighted imaging The sequence parameters are the same.

The above-mentioned vascular reactivity evaluation device can execute the vascular reactivity evaluation method provided by any embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the vascular reactivity evaluation method.

Embodiment four

FIG. 6 is a schematic structural diagram of an electronic device provided by Embodiment 4 of the present invention. Figure 6 shows a block diagram of an exemplary electronic device 12 suitable for use in implementing embodiments of the present invention. The electronic device 12 shown in FIG. 6 is only an example, and should not limit the functions and scope of use of this embodiment of the present invention.

As shown in FIG. 6, electronic device 12 takes the form of a general-purpose computing device. Components of electronic device 12 may include, but are not limited to, one or more processors or processing units 16, system memory 28, bus 18 connecting various system components including system memory 28 and processing unit 16.

Bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor, or a local bus using any of a variety of bus structures. These architectures include, by way of example, but are not limited to Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MAC) bus, Enhanced ISA bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect ( PCI) bus.

Electronic device 12 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by electronic device 12 and include both volatile and nonvolatile media, removable and non-removable media.

System memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and/or cache memory 32 . The electronic device 12 may further include other removable/non-removable, volatile/nonvolatile computer system storage media. By way of example only, storage system 34 may be used to read and write to non-removable, non-volatile magnetic media (not shown in FIG. 6, commonly referred to as a "hard drive"). Although not shown in FIG. 6, a disk drive for reading and writing to removable non-volatile disks (such as "floppy disks") may be provided, as well as for removable non-volatile optical disks (such as CD-ROM, DVD-ROM or other optical media) CD-ROM drive. In these cases, each drive may be connected to bus 18 via one or more data media interfaces. System memory 28 may include at least one program product having a set (eg, at least one) of program modules configured to perform the functions of various embodiments of the present invention.

Program/utility 40 may be stored, for example, in system memory 28 as a set (at least one) of program modules 42 including, but not limited to, an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include the implementation of the network environment. Program modules 42 generally perform the functions and/or methodologies of the described embodiments of the invention.

The electronic device 12 may also communicate with one or more external devices 14 (e.g., a keyboard, pointing device, display 24, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 12, and/or communicate with Any device (eg, network card, modem, etc.) that enables the electronic device 12 to communicate with one or more other computing devices. Such communication may occur through input/output (I/O) interface 22 . Moreover, the electronic device 12 can also communicate with one or more networks (such as a local area network (LAN), a wide area network (WAN) and/or a public network such as the Internet) through the network adapter 20 . As shown in FIG. 6 , network adapter 20 communicates with other modules of electronic device 12 via bus 18 . It should be appreciated that although not shown in FIG. 6, other hardware and/or software modules may be used in conjunction with electronic device 12, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape Drives and data backup storage systems, etc.

The processing unit 16 executes various functional applications and data processing by running the programs stored in the system memory 28 , for example, realizing a method for evaluating vascular reactivity provided by the embodiment of the present invention.

Embodiment five

Embodiment 5 of the present invention also provides a storage medium containing computer-executable instructions. When the computer-executable instructions are executed by a computer processor, a method for evaluating vascular reactivity is provided. The method includes: acquiring a target object A first susceptibility-weighted imaging of a brain region in a free-breathing state and a second susceptibility-weighted imaging of the target subject in a breath-holding state; determining a vascularity map of the brain region; according to the first Determining a first oxygen uptake fraction of target blood vessels in the brain region in a free-breathing state using susceptibility-weighted imaging and the vascular distribution atlas; The second oxygen uptake fraction of the target blood vessel in the region under breath-holding state; determine the evaluation index of the vascular reactivity of the target blood vessel according to the first oxygen uptake fraction and the second oxygen uptake fraction of the target blood vessel, based on The evaluation index evaluates the vascular reactivity of the target blood vessel.

The computer storage medium in the embodiments of the present invention may use any combination of one or more computer-readable media. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (non-exhaustive list) of computer readable storage media include: electrical connections with one or more leads, portable computer disks, hard disks, random access memory (RAM), read only memory (ROM), Erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination of the above. In this document, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a data signal carrying computer readable program code in baseband or as part of a carrier wave. Such propagated data signals may take many forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the foregoing. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. .

Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including - but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out operations of embodiments of the present invention may be written in one or more programming languages, or combinations thereof, including object-oriented programming languages—such as Java, Smalltalk, C++, including A conventional procedural programming language - such as "C" or a similar programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In cases involving a remote computer, the remote computer can be connected to the user computer through any kind of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (such as through an Internet service provider). Internet connection).

Note that the above are only preferred embodiments of the present invention and applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present invention, and the present invention The scope is determined by the scope of the appended claims.

Claims (10)

1. A method for evaluating vascular reactivity, comprising:

   acquiring a first susceptibility-weighted imaging of a brain region of a target subject in a free-breathing state and a second susceptibility-weighted imaging of the target subject in a breath-holding state;

   determining a vascularity map of the brain region;

   determining a first oxygen uptake fraction of a target blood vessel in the brain region in a freely breathing state according to the first magnetic susceptibility weighted imaging and the blood vessel distribution map;

   determining a second oxygen uptake fraction of a target blood vessel in the brain region in a breath-hold state according to the second susceptibility-weighted imaging and the blood vessel distribution map;

   An evaluation index of the vascular reactivity of the target blood vessel is determined according to the first oxygen uptake fraction and the second oxygen uptake fraction of the target blood vessel, and the vascular reactivity of the target blood vessel is evaluated based on the evaluation index.
2. The method according to claim 1, wherein the determining the vascular distribution map of the brain region comprises:

   Acquiring a third susceptibility-weighted imaging of the brain region of the target subject in a freely breathing state, wherein the acquisition time of the third susceptibility-weighted imaging is greater than the acquisition time of the first susceptibility-weighted imaging;

   determining a third quantitative magnetic susceptibility map corresponding to the third magnetic susceptibility weighted imaging;

   A blood vessel distribution map of the brain region is determined according to the prior knowledge template of the brain region, the third magnetic susceptibility weighted imaging, and the third quantitative magnetic susceptibility map.
3. The method according to claim 1, wherein the determining the first oxygen uptake fraction of the brain region in a free-breathing state according to the first susceptibility-weighted imaging sum and blood vessel distribution atlas comprises:

   determining a first quantitative magnetic susceptibility map corresponding to the first magnetic susceptibility weighted imaging;

   For each voxel of the target blood vessel in the blood vessel distribution map, according to the quantitative magnetic susceptibility of each voxel in the first quantitative magnetic susceptibility map and the relationship between the quantitative magnetic susceptibility and the oxygen uptake fraction established in advance, calculate The first fraction of oxygen uptake for each voxel within the target vessel.
4. The method according to claim 2, wherein said determining the third quantitative magnetic susceptibility spectrum corresponding to the third magnetic susceptibility weighted imaging comprises:

   generating a brain mask image based on the raw magnitude image of the third susceptibility-weighted imaging;

   determining an intracerebral susceptibility-weighted imaging corresponding to an inner brain area in the brain region of the third susceptibility-weighted imaging;

   performing dephasing processing and background field removal processing on the original phase image of the susceptibility-weighted imaging in the brain to obtain a target phase image;

   The magnetic susceptibility distribution of each voxel in the internal brain region is calculated according to the amplitude prior information of the brain mask image, the target phase image and the least square method, and a third quantitative magnetic susceptibility map is reconstructed.
5. The method according to claim 4, wherein said dephasing the original phase image of the magnetic susceptibility weighted imaging in the brain comprises:

   According to the phase information of multiple voxels of the original phase image of the susceptibility-weighted imaging in the brain and the scan time, the regional phase winding is estimated, and the aliasing phase is reversely solved based on the estimation result, and the weighted imaging of the magnetic susceptibility in the brain is obtained. real phase information.
6. The method according to claim 5, wherein the dephasing and background field removal processing of the original phase image of the intracerebral magnetic susceptibility weighted imaging comprises:

   Based on the characteristic that the orthogonal product of the unit dipole field in the brain region and the unit dipole field of any background field in the brain region is less than a preset threshold, the background field of the original phase image of the magnetic susceptibility weighted imaging in the brain is removed. .
7. The method according to claim 3, wherein the relationship between the quantitative magnetic susceptibility and the oxygen uptake fraction is determined based on the following formula:

   

   Wherein, OEF is the oxygen uptake fraction of the voxel; Δχvein _-CSF = _χvein - _χCSF , _χvein is the quantitative magnetic susceptibility of the venous vessels in the quantitative magnetic susceptibility atlas, and _χCSF is the cerebrospinal fluid in the anterior region of the lateral ventricle Quantitative magnetic susceptibility; Δχ _vein-CSF represents the difference in magnetic susceptibility between venous blood vessels and cerebrospinal fluid; Δχ _deoxy is the difference in magnetic susceptibility between oxygenated and deoxygenated red blood cells per hematocrit; Δχ _oxy-CSF = χ _oxy -χ _CSF , Δχ _oxy-CSF is the magnetic susceptibility difference between oxygenated red blood cells and cerebrospinal fluid; χ _oxy is the magnetic susceptibility of oxygenated red blood cells; Hct is the hematocrit; pv is the correction parameter for the partial volume effect of the acquisition voxel.
8. The method according to claim 1, wherein the determining the evaluation index of the vascular reactivity of the target blood vessel according to the first oxygen uptake fraction and the second oxygen uptake fraction of the target blood vessel comprises:

   For each voxel of the target blood vessel, a score difference between the first oxygen uptake fraction and the second oxygen uptake score is calculated, and an evaluation index of vascular reactivity of the target blood vessel is determined according to the score difference.
9. The method according to claim 1, wherein the time difference between the acquisition time of the first susceptibility-weighted imaging and the acquisition time of the second susceptibility-weighted imaging is within a preset difference range, the The parameters of the scan sequence used in the first susceptibility-weighted imaging and the second susceptibility-weighted imaging are the same.
10. An evaluation device for vascular reactivity, characterized by comprising:

    A susceptibility-weighted imaging acquisition module, configured to acquire a first susceptibility-weighted imaging of the brain region of the target subject in a free-breathing state and a second susceptibility-weighted imaging of the target subject in a breath-holding state;

    A blood vessel distribution map determination module, configured to determine the blood vessel distribution map of the brain region;

    A first oxygen uptake fraction determination module, configured to determine the first oxygen uptake fraction of the target blood vessel in the brain region in a freely breathing state according to the first magnetic susceptibility weighted imaging and the blood vessel distribution map;

    A second oxygen uptake fraction determination module, configured to determine a second oxygen uptake fraction of the target blood vessel in the brain region in a breath-holding state according to the second susceptibility-weighted imaging and the blood vessel distribution map;

    A vascular reactivity evaluation module, configured to determine an evaluation index of the vascular reactivity of the target blood vessel according to the first oxygen uptake fraction and the second oxygen uptake fraction of the target blood vessel, and evaluate the target blood vessel based on the evaluation index The vasoreactivity was evaluated.

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