阅读说明：本技术 一种基于磁共振影像的卒中复发预测方法和系统 (Magnetic resonance image-based stroke recurrence prediction method and system ) 是由 王拥军 刘涛 李子孝 荆京 刘子阳 关豪 朱万琳 张喆 程健 姜勇 于 2020-09-29 设计创作，主要内容包括：本发明涉及一种基于磁共振影像的卒中复发预测方法及系统。所述基于磁共振影像的卒中复发预测方法,包括：获取待测患者的磁共振影像集和真实年龄；将所述待测患者的基线DWI-B0核磁共振影像输入至大脑年龄预测模型,得到所述待测患者的大脑预测年龄；将所述待测患者的大脑预测年龄和所述待测患者的真实年龄做差得到所述待测患者的大脑年龄差；将所述待测患者的磁共振影像集和所述待测患者的大脑年龄差输入至卒中复发预测模型,得到待测患者的卒中复发预测结果。本发明实现通过影像学信息就可以预测卒中复发的风险,提高了预测的精度和效率。(The invention relates to a stroke recurrence prediction method and system based on magnetic resonance imaging. The stroke recurrence prediction method based on the magnetic resonance image comprises the following steps: acquiring a magnetic resonance image set and a real age of a patient to be detected; inputting the baseline DWI-B0 nuclear magnetic resonance image of the patient to be detected into a brain age prediction model to obtain the brain predicted age of the patient to be detected; differentiating the predicted brain age of the patient to be detected from the real brain age of the patient to be detected to obtain the brain age differential of the patient to be detected; and inputting the magnetic resonance image set of the patient to be detected and the brain age difference of the patient to be detected into a stroke recurrence prediction model to obtain a stroke recurrence prediction result of the patient to be detected. The invention can predict the recurrence risk of the stroke by the imaging information, and improves the precision and efficiency of prediction.)

1. A stroke recurrence prediction method based on magnetic resonance imaging is characterized by comprising the following steps:

acquiring a magnetic resonance image set and a real age of a patient to be detected; the magnetic resonance image set includes: a baseline DWI-B0 magnetic resonance image, a baseline DWI-B1000 magnetic resonance image, and a lesion segmentation map;

inputting the baseline DWI-B0 nuclear magnetic resonance image of the patient to be detected into a brain age prediction model to obtain the brain predicted age of the patient to be detected; the brain age prediction model is obtained by training an age-based convolutional neural network model by taking a baseline DWI-B0 nuclear magnetic resonance image of a healthy old person as input and the real age of the healthy old person as output; the convolutional neural network model based on the age is constructed on the basis of a dense convolutional neural network by adopting a Pythrch deep learning framework;

differentiating the predicted brain age of the patient to be detected from the real brain age of the patient to be detected to obtain the brain age differential of the patient to be detected;

inputting the magnetic resonance image set of the patient to be detected and the brain age difference of the patient to be detected into a stroke recurrence prediction model to obtain a stroke recurrence prediction result of the patient to be detected; the stroke prediction model is obtained by training a classification model based on the degree of stroke recurrence by taking the magnetic resonance image sets of the patients with different degrees of stroke recurrence and the brain age differences of the patients with different degrees of stroke recurrence as input and taking the corresponding degree of stroke recurrence as output; the classification model based on the degree of stroke recurrence is constructed by a convolutional neural network and a graph convolutional neural network.

2. The method of claim 1, wherein the method for predicting stroke recurrence based on mri is to determine the brain age prediction model as:

acquiring a baseline DWI-B0 magnetic resonance image and a true age of the healthy elderly;

constructing the age-based convolutional neural network model; the age-based convolutional neural network model comprises: five identical convolution blocks; each convolution block comprises two identical convolution units and a maximum pooling layer; each convolution unit comprises a convolution layer, a ReLU activation function and a 3D batch normalization layer;

training the age-based convolutional neural network model by using a back propagation algorithm and a gradient descent algorithm by taking the baseline DWI-B0 magnetic resonance image of the healthy old person as input and the real age of the healthy old person as output to obtain a first brain age prediction model;

and adjusting the first brain age prediction model by adopting a cross-validation method, and determining the adjusted first brain age prediction model as the brain age prediction model.

3. The method of claim 1, wherein the stroke recurrence prediction model is determined by:

acquiring magnetic resonance image sets of stroke patients with different stroke recurrence situations, brain age differences of the stroke patients with different stroke recurrence situations and corresponding stroke recurrence degrees;

constructing the classification model based on the recurrence degree of the stroke; the classification model based on the degree of stroke recurrence includes: the convolution neural network module, the graph convolution neural network module and the full-connection module are connected in sequence;

the magnetic resonance image sets of the stroke patients with different stroke recurrence situations are used as the input of the convolutional neural network module, and the imaging characteristics of the magnetic resonance image sets of the stroke patients with different stroke recurrence situations output by the convolutional neural network module are used as the input of the atlas convolutional neural network module; taking the brain age difference of the stroke patients with different stroke recurrence situations and the spatial position information of the focus of the stroke patients with different stroke recurrence situations output by the graph volume neural network module as the input of the fully-connected module, taking the corresponding stroke recurrence degree as the output of the fully-connected module, and training by adopting a back propagation algorithm and a gradient descent algorithm to obtain a first stroke recurrence prediction model;

and adjusting the first stroke recurrence prediction model by adopting a cross-validation method, and determining the adjusted first stroke recurrence prediction model as a stroke recurrence prediction model.

4. The method of claim 1, further comprising, after the acquiring the mri image set of the patient to be tested, the step of:

and sequentially carrying out image linear registration, image segmentation and image data standardization operation on the magnetic resonance image set.

5. The method of claim 3, wherein the classification model based on the degree of stroke recurrence further comprises an attention mechanism module, an input of the attention mechanism module is connected to an output of the convolutional neural network module, and an output of the attention mechanism module is connected to an input of the fully-connected module; the attention mechanism module is used for performing one-dimensional convolution processing on the spatial position information of the focus according to a channel direction and a graph node direction to obtain a weight of the spatial position information of the focus, and multiplying the weight by the spatial position information of the focus to obtain weighted spatial position information of the focus.

6. A system for predicting stroke recurrence based on magnetic resonance imaging, comprising:

the data acquisition module is used for acquiring a magnetic resonance image set and a real age of a patient to be detected; the magnetic resonance image set includes: a baseline DWI-B0 magnetic resonance image, a baseline DWI-B1000 magnetic resonance image, and a lesion segmentation map;

the brain age prediction module is used for inputting the baseline DWI-B0 nuclear magnetic resonance image of the patient to be detected into a brain age prediction model to obtain the brain predicted age of the patient to be detected; the brain age prediction model is obtained by training an age-based convolutional neural network model by taking a baseline DWI-B0 nuclear magnetic resonance image of a healthy old person as input and the real age of the healthy old person as output; the convolutional neural network model based on the age is constructed on the basis of a dense convolutional neural network by adopting a Pythrch deep learning framework;

the brain age difference calculation module is used for subtracting the predicted brain age of the patient to be detected from the real brain age of the patient to be detected to obtain the brain age difference of the patient to be detected;

the stroke recurrence prediction module is used for inputting the magnetic resonance image set of the patient to be detected and the brain age difference of the patient to be detected into a stroke recurrence prediction model to obtain a stroke recurrence prediction result of the patient to be detected; the stroke prediction model is obtained by training a classification model based on the degree of stroke recurrence by taking the magnetic resonance image sets of the patients with different degrees of stroke recurrence and the brain age differences of the patients with different degrees of stroke recurrence as input and taking the corresponding degree of stroke recurrence as output; the classification model based on the degree of stroke recurrence is constructed by a convolutional neural network and a graph convolutional neural network.

7. The system of claim 6, further comprising: a brain age prediction model determination module for determining the age of the brain,

the brain age prediction model determination module includes:

a first data acquisition unit for acquiring baseline DWI-B0 magnetic resonance images and real age of the healthy elderly;

the convolutional neural network model construction unit based on the age is used for constructing the convolutional neural network model based on the age; the age-based convolutional neural network model comprises: five identical convolution blocks; each convolution block comprises two identical convolution units and a maximum pooling layer; each convolution unit comprises a convolution layer, a ReLU activation function and a 3D batch normalization layer;

the age-based convolutional neural network model training unit is used for training the age-based convolutional neural network model by taking a baseline DWI-B0 magnetic resonance image of the healthy old person as input and the real age of the healthy old person as output and adopting a back propagation algorithm and a gradient descent algorithm to obtain a first brain age prediction model;

and the brain age prediction model determining unit is used for adjusting the first brain age prediction model by adopting a cross validation method and determining the adjusted first brain age prediction model as the brain age prediction model.

8. The system of claim 6, further comprising: a stroke recurrence prediction model determination module for determining a model,

the stroke recurrence prediction model determination module comprises:

the second data acquisition unit is used for acquiring the magnetic resonance image sets of the stroke patients with different stroke recurrence situations, the cerebral age difference of the stroke patients with different stroke recurrence situations and the corresponding stroke recurrence degree;

the classification model construction unit is used for constructing the classification model based on the degree of the stroke recurrence; the classification model based on the degree of stroke recurrence includes: the convolution neural network module, the graph convolution neural network module and the full-connection module are connected in sequence;

the classification model training unit is used for taking the magnetic resonance image sets of the stroke patients with different stroke recurrence situations as the input of the convolutional neural network module, and taking the imaging characteristics of the magnetic resonance image sets of the stroke patients with different stroke recurrence situations output by the convolutional neural network module as the input of the atlas neural network module; taking the brain age difference of the stroke patients with different stroke recurrence situations and the spatial position information of the focus of the stroke patients with different stroke recurrence situations output by the graph volume neural network module as the input of the full-connection module, taking the corresponding stroke recurrence degree as the output, and adopting a back propagation algorithm and a gradient descent algorithm to train to obtain a first stroke recurrence prediction model;

and the stroke recurrence prediction model determining unit is used for adjusting the first stroke recurrence prediction model by adopting a cross-validation method and determining the adjusted first stroke recurrence prediction model as a stroke recurrence prediction model.

9. The system of claim 6, further comprising:

and the image preprocessing module is used for sequentially carrying out image linear registration, image segmentation and image data standardization operation on the magnetic resonance image set.

10. The system of claim 8, wherein the classification model building unit further comprises an attention mechanism module, an input of the attention mechanism module is connected to an output of the convolutional neural network module, and an output of the attention mechanism module is connected to an input of the fully-connected module; the attention mechanism module is used for performing one-dimensional convolution processing on the spatial position information of the focus according to a channel direction and a graph node direction to obtain a weight of the spatial position information of the focus, and multiplying the weight by the spatial position information of the focus to obtain weighted spatial position information of the focus.

Technical Field

The invention belongs to the technical field of health management, and particularly relates to a stroke recurrence prediction method and system based on magnetic resonance imaging.

Background

Cerebral apoplexy (also called apoplexy and cerebrovascular accident, CVA) is an acute cerebrovascular disease, is the first cause of death and disability of adult people in China, and has the characteristics of high morbidity, high disability rate, high mortality rate and high recurrence rate. At present, the treatment means aiming at the cerebral apoplexy is limited, and the curative effect is not ideal, so the prevention is the best treatment measure at the present stage.

For doctors, it is necessary to effectively evaluate which patients are affected by the disease at the future time point greatly and have high recurrence risk, so as to take corresponding measures in the subsequent treatment. The currently widely used clinical evaluation method for stroke recurrence is mainly a scale evaluation method, such as the Essen rating scale. The Essen scale is a stroke risk prediction tool developed for brain stroke subgroup analysis, and the Essen scale can be used for obtaining different patient vulnerability degrees with different risks, wherein the highest score is 9. If the score is 0-2, the recurrence rate of the cerebral apoplexy is lower; however, 3 points is a boundary value, the recurrence probability of the patient who is more than 3 points is high, and the higher the score is, the higher the risk of stroke and compound cardiovascular events is, but the process of summarizing and evaluating the risk factors such as the age of the stroke patient and the past medical history according to the Essen scale does not combine with image information, so that the evaluation speed is slow, and the result is inaccurate.

Therefore, there is an urgent need for a method and system for accurately and rapidly predicting the risk of stroke recurrence.

Disclosure of Invention

The invention aims to provide a stroke recurrence prediction method and system based on magnetic resonance imaging so as to accurately and rapidly predict stroke recurrence risk.

In order to achieve the purpose, the invention provides the following scheme:

a stroke recurrence prediction method based on magnetic resonance imaging comprises the following steps:

acquiring a magnetic resonance image set and a real age of a patient to be detected; the magnetic resonance image set includes: a baseline DWI-B0 magnetic resonance image, a baseline DWI-B1000 magnetic resonance image, and a lesion segmentation map;

inputting the baseline DWI-B0 nuclear magnetic resonance image of the patient to be detected into a brain age prediction model to obtain the brain predicted age of the patient to be detected; the brain age prediction model is obtained by training an age-based convolutional neural network model by taking a baseline DWI-B0 nuclear magnetic resonance image of a healthy old person as input and the real age of the healthy old person as output; the convolutional neural network model based on the age is constructed on the basis of a dense convolutional neural network by adopting a Pythrch deep learning framework;

differentiating the predicted brain age of the patient to be detected from the real brain age of the patient to be detected to obtain the brain age differential of the patient to be detected;

inputting the magnetic resonance image set of the patient to be detected and the brain age difference of the patient to be detected into a stroke recurrence prediction model to obtain a stroke recurrence prediction result of the patient to be detected; the stroke prediction model is obtained by training a classification model based on the degree of stroke recurrence by taking the magnetic resonance image sets of the patients with different degrees of stroke recurrence and the brain age differences of the patients with different degrees of stroke recurrence as input and taking the corresponding degree of stroke recurrence as output; the classification model based on the degree of stroke recurrence is constructed by a convolutional neural network and a graph convolutional neural network.

Optionally, the method for determining the brain age prediction model includes:

acquiring a baseline DWI-B0 magnetic resonance image and a true age of the healthy elderly;

constructing the age-based convolutional neural network model; the age-based convolutional neural network model comprises: five identical convolution blocks; each convolution block comprises two identical convolution units and a maximum pooling layer; each convolution unit comprises a convolution layer, a ReLU activation function and a 3D batch normalization layer;

training the age-based convolutional neural network model by using a back propagation algorithm and a gradient descent algorithm by taking the baseline DWI-B0 magnetic resonance image of the healthy old person as input and the real age of the healthy old person as output to obtain a first brain age prediction model;

and adjusting the first brain age prediction model by adopting a cross-validation method, and determining the adjusted first brain age prediction model as the brain age prediction model.

Optionally, the method for determining the stroke recurrence prediction model includes:

acquiring magnetic resonance image sets of stroke patients with different stroke recurrence situations, brain age differences of the stroke patients with different stroke recurrence situations and corresponding stroke recurrence degrees;

constructing the classification model based on the recurrence degree of the stroke; the classification model based on the degree of stroke recurrence includes: the convolution neural network module, the graph convolution neural network module and the full-connection module are connected in sequence;

the magnetic resonance image sets of the stroke patients with different stroke recurrence situations are used as the input of the convolutional neural network module, and the imaging characteristics of the magnetic resonance image sets of the stroke patients with different stroke recurrence situations output by the convolutional neural network module are used as the input of the atlas convolutional neural network module; taking the brain age difference of the stroke patients with different stroke recurrence situations and the spatial position information of the focus of the stroke patients with different stroke recurrence situations output by the graph volume neural network module as the input of the fully-connected module, taking the corresponding stroke recurrence degree as the output of the fully-connected module, and training by adopting a back propagation algorithm and a gradient descent algorithm to obtain a first stroke recurrence prediction model;

and adjusting the first stroke recurrence prediction model by adopting a cross-validation method, and determining the adjusted first stroke recurrence prediction model as a stroke recurrence prediction model.

Optionally, after the acquiring the magnetic resonance image set of the patient to be measured, the method further includes:

and sequentially carrying out image linear registration, image segmentation and image data standardization operation on the magnetic resonance image set.

Optionally, the classification model based on the degree of stroke recurrence further includes an attention mechanism module, an input end of the attention mechanism module is connected to an output end of the graph convolution neural network module, and an output end of the attention mechanism module is connected to an input end of the full-connection module; the attention mechanism module is used for performing one-dimensional convolution processing on the spatial position information of the focus according to a channel direction and a graph node direction to obtain a weight of the spatial position information of the focus, and multiplying the weight by the spatial position information of the focus to obtain weighted spatial position information of the focus.

A magnetic resonance image-based stroke recurrence prediction system, comprising:

the data acquisition module is used for acquiring a magnetic resonance image set and a real age of a patient to be detected; the magnetic resonance image set includes: a baseline DWI-B0 magnetic resonance image, a baseline DWI-B1000 magnetic resonance image, and a lesion segmentation map;

the brain age prediction module is used for inputting the baseline DWI-B0 nuclear magnetic resonance image of the patient to be detected into a brain age prediction model to obtain the brain predicted age of the patient to be detected; the brain age prediction model is obtained by training an age-based convolutional neural network model by taking a baseline DWI-B0 nuclear magnetic resonance image of a healthy old person as input and the real age of the healthy old person as output; the convolutional neural network model based on the age is constructed on the basis of a dense convolutional neural network by adopting a Pythrch deep learning framework;

the brain age difference calculation module is used for subtracting the predicted brain age of the patient to be detected from the real brain age of the patient to be detected to obtain the brain age difference of the patient to be detected;

the stroke recurrence prediction module is used for inputting the magnetic resonance image set of the patient to be detected and the brain age difference of the patient to be detected into a stroke recurrence prediction model to obtain a stroke recurrence prediction result of the patient to be detected; the stroke prediction model is obtained by training a classification model based on the degree of stroke recurrence by taking the magnetic resonance image sets of the patients with different degrees of stroke recurrence and the brain age differences of the patients with different degrees of stroke recurrence as input and taking the corresponding degree of stroke recurrence as output; the classification model based on the degree of stroke recurrence is constructed by a convolutional neural network and a graph convolutional neural network.

Optionally, the system for predicting stroke recurrence based on magnetic resonance image further includes: a brain age prediction model determination module for determining the age of the brain,

the brain age prediction model determination module includes:

a first data acquisition unit for acquiring baseline DWI-B0 magnetic resonance images and real age of the healthy elderly;

the convolutional neural network model construction unit based on the age is used for constructing the convolutional neural network model based on the age; the age-based convolutional neural network model comprises: five identical convolution blocks; each convolution block comprises two identical convolution units and a maximum pooling layer; each convolution unit comprises a convolution layer, a ReLU activation function and a 3D batch normalization layer;

the age-based convolutional neural network model training unit is used for training the age-based convolutional neural network model by taking a baseline DWI-B0 magnetic resonance image of the healthy old person as input and the real age of the healthy old person as output and adopting a back propagation algorithm and a gradient descent algorithm to obtain a first brain age prediction model;

and the brain age prediction model determining unit is used for adjusting the first brain age prediction model by adopting a cross validation method and determining the adjusted first brain age prediction model as the brain age prediction model.

Optionally, the system for predicting stroke recurrence based on magnetic resonance image further includes: a stroke recurrence prediction model determination module for determining a model,

the stroke recurrence prediction model determination module comprises:

the second data acquisition unit is used for acquiring the magnetic resonance image sets of the stroke patients with different stroke recurrence situations, the cerebral age difference of the stroke patients with different stroke recurrence situations and the corresponding stroke recurrence degree;

the classification model construction unit is used for constructing the classification model based on the degree of the stroke recurrence; the classification model based on the degree of stroke recurrence includes: the convolution neural network module, the graph convolution neural network module and the full-connection module are connected in sequence;

the classification model training unit is used for taking the magnetic resonance image sets of the stroke patients with different stroke recurrence situations as the input of the convolutional neural network module, and taking the imaging characteristics of the magnetic resonance image sets of the stroke patients with different stroke recurrence situations output by the convolutional neural network module as the input of the atlas neural network module; taking the brain age difference of the stroke patients with different stroke recurrence situations and the spatial position information of the focus of the stroke patients with different stroke recurrence situations output by the graph volume neural network module as the input of the full-connection module, taking the corresponding stroke recurrence degree as the output, and adopting a back propagation algorithm and a gradient descent algorithm to train to obtain a first stroke recurrence prediction model;

and the stroke recurrence prediction model determining unit is used for adjusting the first stroke recurrence prediction model by adopting a cross-validation method and determining the adjusted first stroke recurrence prediction model as a stroke recurrence prediction model.

Optionally, the system for predicting stroke recurrence based on magnetic resonance image further includes:

and the image preprocessing module is used for sequentially carrying out image linear registration, image segmentation and image data standardization operation on the magnetic resonance image set.

Optionally, the classification model building unit based on the degree of stroke recurrence further includes an attention mechanism module, an input end of the attention mechanism module is connected to an output end of the graph convolution neural network module, and an output end of the attention mechanism module is connected to an input end of the full-connection module; the attention mechanism module is used for performing one-dimensional convolution processing on the spatial position information of the focus according to a channel direction and a graph node direction to obtain a weight of the spatial position information of the focus, and multiplying the weight by the spatial position information of the focus to obtain weighted spatial position information of the focus.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects: according to the method, based on the magnetic resonance image acquired at the time of admission and the longitudinal follow-up assessment result, a high-dimensional model of the relationship between the imaging characteristics and the future recurrence situation is established through a deep learning method, the risk of stroke recurrence can be predicted through imaging information, and the prediction precision and efficiency are improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

Fig. 1 is a flowchart of a method for predicting stroke recurrence based on magnetic resonance imaging according to embodiment 1 of the present invention;

FIG. 2 is a schematic diagram illustrating the components of a convolutional neural network module in embodiment 1 of the present invention;

FIG. 3 is a schematic diagram showing the composition of a classification model based on the degree of recurrence of stroke in example 1 of the present invention;

FIG. 4 is a schematic diagram showing the components of an attention mechanism module in embodiment 1 of the present invention;

FIG. 5 is a diagram illustrating the image segmentation result in example 1 of the present invention;

fig. 6 is a schematic diagram illustrating a system for predicting stroke recurrence based on mri according to embodiment 2 of the present invention;

fig. 7 is a schematic composition diagram of the age-based convolutional neural network model in example 3.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Example 1

As shown in fig. 1, a method for predicting stroke recurrence based on magnetic resonance imaging includes:

101: acquiring a magnetic resonance image set and a real age of a patient to be detected. The magnetic resonance image set includes: baseline DWI-B0 magnetic resonance images, baseline DWI-B1000 magnetic resonance images, and lesion segmentation maps.

102: inputting the baseline DWI-B0 nuclear magnetic resonance image of the patient to be detected into a brain age prediction model to obtain the brain predicted age of the patient to be detected. The brain age prediction model is obtained by training an age-based convolutional neural network model by taking a baseline DWI-B0 nuclear magnetic resonance image of a healthy old person as input and the real age of the healthy old person as output; the convolutional neural network model based on the age is constructed on the basis of a dense convolutional neural network by adopting a Pythrch deep learning framework.

103: and differentiating the predicted brain age of the patient to be detected and the real brain age of the patient to be detected to obtain the brain age differential of the patient to be detected.

104: and inputting the magnetic resonance image set of the patient to be detected and the brain age difference of the patient to be detected into a stroke recurrence prediction model to obtain a stroke recurrence prediction result of the patient to be detected. The stroke prediction model is obtained by training a classification model based on the degree of stroke recurrence by taking the magnetic resonance image sets of the patients with different degrees of stroke recurrence and the brain age differences of the patients with different degrees of stroke recurrence as input and taking the corresponding degree of stroke recurrence as output; the classification model based on the degree of stroke recurrence is constructed by a convolutional neural network and a graph convolutional neural network.

The determination method of the brain age prediction model may be:

a baseline DWI-B0 magnetic resonance image and true age of the healthy elderly are obtained.

Constructing the age-based convolutional neural network model; the age-based convolutional neural network model comprises: five identical convolution blocks; each of the convolution blocks includes two identical convolution units and one maximum pooling layer (step size 2 × 2 × 2); each convolution unit includes one convolution layer (step size 3 × 3 × 3), one ReLU activation function, and one 3D batch normalization layer.

And training the age-based convolutional neural network model by using the baseline DWI-B0 magnetic resonance image of the healthy old person as input and the real age of the healthy old person as output and adopting a back propagation algorithm and a gradient descent algorithm, and selecting model parameters (convolution kernels and weights of full connection layers) with high prediction precision (lowest mean error) and strong generalization performance (small error difference between a training set and a testing set) for storage to obtain a first brain age prediction model.

And adjusting hyper-parameters (learning rate, channel number, convolution kernel size and L2 weight attenuation coefficient) of the first brain age prediction model by adopting a cross validation method, and determining the adjusted first brain age prediction model as the brain age prediction model.

The determination method of the stroke recurrence prediction model can be as follows:

acquiring the magnetic resonance image set of the stroke patient with different stroke recurrence conditions, the brain age difference of the stroke patient with different stroke recurrence conditions and the corresponding stroke recurrence degree.

Constructing the classification model based on the recurrence degree of the stroke; as shown in fig. 3, the classification model based on the degree of stroke recurrence includes: the system comprises a convolution neural network module, a graph convolution neural network module and a full-connection module which are connected in sequence.

The magnetic resonance image sets of the stroke patients with different stroke recurrence situations are used as the input of the convolutional neural network module, and the imaging characteristics of the magnetic resonance image sets of the stroke patients with different stroke recurrence situations output by the convolutional neural network module are used as the input of the atlas convolutional neural network module; with the cerebral age difference of the apoplexy patient of different apoplexy recurrence circumstances with the spatial position information of the apoplexy patient's of the different apoplexy recurrence circumstances of graph convolution neural network module output does the input of full link module uses corresponding apoplexy recurrence degree as the output of full link module adopts counter-propagating algorithm and gradient descent algorithm to train, selects the model parameter (convolution kernel and the weight of full link layer) of predicting the precision height (mean error is minimum), generalization performance reinforce (training set and test set error difference are little) and preserves, obtains first apoplexy recurrence prediction model.

And adjusting hyper-parameters (learning rate, channel number, convolution kernel size and L2 weight attenuation coefficient) of the first stroke recurrence prediction model by adopting a cross-validation method, and determining the adjusted first stroke recurrence prediction model as a stroke recurrence prediction model.

Wherein, after the acquiring the magnetic resonance image set of the patient to be measured, the method further comprises:

and sequentially carrying out image linear registration, image segmentation and image data standardization operation on the magnetic resonance image set.

In order to highlight key characteristic information extracted from the graph convolution network, an attention mechanism module is designed and added behind the graph convolution neural network module. The classification model based on the recurrence degree of stroke further comprises an attention mechanism module, wherein the input end of the attention mechanism module is connected with the output end of the graph convolution neural network module, and the output end of the attention mechanism module is connected with the input end of the full-connection module; as shown in fig. 4, the attention mechanism module is configured to perform one-dimensional convolution processing on the spatial position information of the lesion according to a channel direction and a graph node direction to obtain a weight of the spatial position information of the lesion, and then multiply the weight by the spatial position information of the lesion, so as to perform weighting processing on the features to highlight important features and weaken invalid information, thereby obtaining the weighted spatial position information of the lesion.

In order to prevent the imaging difference from interfering with the model, the image is subjected to an image registration process, the image registration process is to perform a linear registration operation on the input image, the baseline DWI magnetic resonance image can be subjected to the linear registration by using the MNI152-2mm template as a reference by using the FLIRT command in FSL 5.0, the size of the registered image is 91 × 109 × 91, and the resolution is 2 mm.

The image segmentation process specifically comprises the following steps: dividing an input image into 6 equal image blocks: halving along the X-axis and trisecting along the Y-axis, and downsampling the original image into image blocks of the same size as the halved image blocks to obtain a total of 7 image blocks of the same size, the result is shown in fig. 5.

In order to prevent the interference of the voxel value distribution in the image data to the model caused by the difference of the image acquisition equipment, the image data is standardized. The image data standardization specifically comprises: and calculating the mean value and the standard deviation of the voxels in the brain contour, and performing Gaussian normalization on the voxels in the brain contour.

Wherein, will the magnetic resonance image set of patient that awaits measuring with the brain age difference input of patient that awaits measuring to the prediction model of apoplexy relapse, the concrete process of the prediction result of the apoplexy relapse that obtains patient that awaits measuring is:

inputting the magnetic resonance image set of the patient to be detected and the brain age difference of the patient to be detected into a trained classification model based on the degree of stroke recurrence, extracting the output of a 32-dimensional full-connection layer in a full-connection module in the classification model based on the degree of stroke recurrence after calculation by a classification model network based on the degree of stroke recurrence, storing the output as high-dimensional iconography information, then displaying the high-dimensional iconography information and DWI-B0 images in the magnetic resonance image set of the patient to be detected in an overlapping manner, acquiring a thermodynamic diagram image of a corresponding focus part, and obtaining a stroke recurrence prediction result of the corresponding part according to the thermodynamic diagram image.

Example 2

As shown in fig. 6, a system for predicting stroke recurrence based on magnetic resonance imaging includes:

the data acquisition module A1 is used for acquiring a magnetic resonance image set and a real age of a patient to be detected; the magnetic resonance image set includes: baseline DWI-B0 magnetic resonance images, baseline DWI-B1000 magnetic resonance images, and lesion segmentation maps.

The brain age prediction module A2 is used for inputting the baseline DWI-B0 nuclear magnetic resonance image of the patient to be detected into a brain age prediction model to obtain the brain predicted age of the patient to be detected; the brain age prediction model is obtained by training an age-based convolutional neural network model by taking a baseline DWI-B0 nuclear magnetic resonance image of a healthy old person as input and the real age of the healthy old person as output; the convolutional neural network model based on the age is constructed on the basis of a dense convolutional neural network by adopting a Pythrch deep learning framework.

And the brain age difference calculation module A3 is used for subtracting the predicted brain age of the patient to be tested from the real brain age of the patient to be tested to obtain the brain age of the patient to be tested.

The stroke recurrence prediction module A4 is used for inputting the magnetic resonance image set of the patient to be detected and the brain age difference of the patient to be detected into a stroke recurrence prediction model to obtain a stroke recurrence prediction result of the patient to be detected; the stroke prediction model is obtained by training a classification model based on the degree of stroke recurrence by taking the magnetic resonance image sets of the patients with different degrees of stroke recurrence and the brain age differences of the patients with different degrees of stroke recurrence as input and taking the corresponding degree of stroke recurrence as output; the classification model based on the degree of stroke recurrence is constructed by a convolutional neural network and a graph convolutional neural network.

As an optional implementation, the system for predicting stroke recurrence based on magnetic resonance image further includes: a brain age prediction model determination module, the brain age prediction model determination module comprising:

a first data acquisition unit for acquiring baseline DWI-B0 magnetic resonance images and real age of the healthy elderly; the convolutional neural network model construction unit based on the age is used for constructing the convolutional neural network model based on the age; the age-based convolutional neural network model comprises: five identical convolution blocks; each convolution block comprises two identical convolution units and a maximum pooling layer; each convolution unit comprises a convolution layer, a ReLU activation function and a 3D batch normalization layer; the age-based convolutional neural network model training unit is used for training the age-based convolutional neural network model by taking a baseline DWI-B0 magnetic resonance image of the healthy old person as input and the real age of the healthy old person as output and adopting a back propagation algorithm and a gradient descent algorithm to obtain a first brain age prediction model; and the brain age prediction model determining unit is used for adjusting the first brain age prediction model by adopting a cross validation method and determining the adjusted first brain age prediction model as the brain age prediction model.

As an optional implementation, the system for predicting stroke recurrence based on magnetic resonance image further includes: a stroke recurrence prediction model determination module, the stroke recurrence prediction model determination module comprising: the second data acquisition unit is used for acquiring the magnetic resonance image sets of the stroke patients with different stroke recurrence situations, the cerebral age difference of the stroke patients with different stroke recurrence situations and the corresponding stroke recurrence degree; the classification model construction unit is used for constructing the classification model based on the degree of the stroke recurrence; the classification model based on the degree of stroke recurrence includes: the convolution neural network module, the graph convolution neural network module and the full-connection module are connected in sequence; the classification model training unit is used for taking the magnetic resonance image sets of the stroke patients with different stroke recurrence situations as the input of the convolutional neural network module, and taking the imaging characteristics of the magnetic resonance image sets of the stroke patients with different stroke recurrence situations output by the convolutional neural network module as the input of the atlas neural network module; taking the brain age difference of the stroke patients with different stroke recurrence situations and the spatial position information of the focus of the stroke patients with different stroke recurrence situations output by the graph volume neural network module as the input of the full-connection module, taking the corresponding stroke recurrence degree as the output, and adopting a back propagation algorithm and a gradient descent algorithm to train to obtain a first stroke recurrence prediction model; and the stroke recurrence prediction model determining unit is used for adjusting the first stroke recurrence prediction model by adopting a cross-validation method and determining the adjusted first stroke recurrence prediction model as a stroke recurrence prediction model.

As an optional implementation, the system for predicting stroke recurrence based on magnetic resonance image further includes:

and the image preprocessing module is used for sequentially carrying out image linear registration, image segmentation and image data standardization operation on the magnetic resonance image set.

As an optional embodiment, the classification model building unit based on the degree of stroke recurrence further includes an attention mechanism module, an input end of the attention mechanism module is connected with an output end of the graph convolution neural network module, and an output end of the attention mechanism module is connected with an input end of the full connection module; the attention mechanism module is used for performing one-dimensional convolution processing on the spatial position information of the focus according to a channel direction and a graph node direction to obtain a weight of the spatial position information of the focus, and multiplying the weight by the spatial position information of the focus to obtain weighted spatial position information of the focus.

Example 3

The present embodiment differs from the above embodiments in that:

wherein, as shown in fig. 7, the number of the first convolution block feature channels in the age-based convolution neural network model can be set to 8, and doubled after entering the next convolution block, so as to deduce a sufficiently rich brain information representation.

In addition, in order to alleviate the problem of gradient disappearance and improve the utilization efficiency of features, the feature maps learned by different convolution blocks are connected in series, so that the variables input by subsequent layers are increased, and the feature utilization efficiency and the learning effect of the network are improved. Each convolution block integrates the information of all the output feature maps of the previous convolution blocks to serve as input, and because the sizes of the output feature maps of different convolution blocks are different, the feature maps are firstly downsampled in a maximum pooling mode, the sizes of the feature maps are changed, then the feature maps output by the convolution blocks are connected in series with the feature maps output by other convolution blocks to form a single tensor which serves as the input of the current convolution block, and after the last convolution block is finished, a global average pooling layer is used for vectorizing the feature maps into a feature vector. The final age prediction uses a one-dimensional convolutional layer plus the ReLU activation function, which maps the feature vectors from the global average pooling to a single output value.

The convolutional neural network module is of a convolutional neural network structure and aims to extract the implicit iconographic features in an input image through the calculation of convolutional layers, and comprises 2 repeated Root convolutional blocks and 4 repeated ResBLK convolutional blocks, wherein the Root convolutional blocks are 3 x 3 convolutional kernels with the channel number of 64, and the ResBLK convolutional blocks are convolutional blocks consisting of 3 convolutional units, each convolutional unit comprises 1 convolutional layer, 1 batch normalization layer and a ReReLU activation layer, as shown in Table 1, and the input of the first convolutional unit and the output of the third convolutional unit are connected to form a short-circuit connection form so as to improve the feature utilization efficiency and relieve the gradient disappearance phenomenon. The specific network structure and the number of channels of different modules are shown in fig. 2.

TABLE 1 convolutional neural network Module Structure composition Table

The graph convolution network module of this embodiment performs downsampling and global tie pooling on feature maps after convolution of 7 image blocks to obtain 7 graph nodes, and then performs convolution in two steps (along the node direction and the channel direction) by 1-dimensional convolution, where the convolution kernel size is 3 and the step size is set to 1.

The convolutional neural network module and the graph convolutional neural network module in the embodiment can efficiently extract feature information from an input image, the fully-connected module is used for fusing the iconography information and the brain age difference, and the dimension of the feature is reduced to 16 dimensions through Bilinear processing of the information extracted from the convolutional neural network module; and (3) upgrading the brain age characteristic to 16 dimensions through a full connection layer, combining the brain age characteristic and the full connection layer in a cascade manner, outputting the combined brain age characteristic and the full connection layer in a 32-dimension manner through a 2-dimension full connection layer to obtain model two-classification output, and obtaining whether the stroke recurrence is high recurrence risk or low recurrence risk.

The invention has the following characteristics:

1. the invention uses a deep learning method to construct a stroke recurrence risk assessment system based on magnetic resonance image data, and can analyze the magnetic resonance image data by means of a deep neural network, thereby obtaining the imaging characteristics related to stroke recurrence.

2. The invention extracts 'brain age difference' from the image as key iconography.

3. The invention uses the classification model network structure based on the recurrence degree of the stroke, and the included graph convolution neural network can efficiently extract the spatial position information characteristics included in the focus in the magnetic resonance image.

4. By means of the strong computing power of the computer, the method can quickly and accurately extract the imaging characteristics related to the recurrence of the stroke based on the image information, and avoids complicated evaluation time.

5. The present invention also uses the age difference of the brain as an important recurrence evaluation feature, and also can be used to evaluate the aging characteristics of the brain where the current image input is located.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.