Coronary stenosis degree evaluation model training method and evaluation system
Technical Field
The invention relates to the field of coronary image analysis, in particular to a training method and an evaluation system of a coronary stenosis degree evaluation model.
Background
AI automatically monitors features such as calcification, soft spots, etc., and obtains a prediction model from a large number of samples for training, so the samples are important inputs. The sample includes raw scan data that can be quickly acquired by the instrument and a label (i.e., an answer) that requires a significant amount of manual intervention.
An important intermediate result of coronary diagnosis and treatment is stenosis degree, which is quantified in combination with the original scan data, and which is useful for the diagnosis of the patient by the expert, and the difficulty of calculating stenosis degree is especially the identification of soft plaque and the identification of partially punctiform calcified mixed plaque, for which the identification requires a certain experience, which is usually evaluated by the expert. However, since different hospitals or doctors have different evaluation strategies and make and break the evaluation of the same original data, the AI has great limitations in practical application, and the analysis result has great limitations, and cannot give a corresponding reference to a specific expert, but may cause misleading.
Disclosure of Invention
The invention aims to provide a coronary stenosis evaluation model training method to obtain a coronary stenosis evaluation model which accords with a specific expert evaluation strategy as much as possible.
In order to achieve the purpose, the invention adopts the following technical scheme:
the training method of the coronary stenosis degree evaluation model comprises the following steps:
s1, obtaining a cloud sample set: collecting samples from each hospital by a cloud method, the samples comprising raw scan data and stenosis score to form a cloud sample set;
s2, manually labeling and classifying the samples extracted from the cloud sample set and obtaining the cloud scores of the classified samples;
s3, training an image classification model based on the labeled classification sample;
s4, obtaining a specific sample set and classifying: collecting specific samples corresponding to a certain hospital or a certain expert in the hospital from the certain hospital to form a specific sample set; inputting a specific sample set into a classification model for classification;
s5, determining the difficulty value of the specific sample: determining the difficulty value of the specific sample according to the difference between the actual score of the specific sample and the cloud score of the class where the specific sample is located based on the classification result;
s6, confirming the difficulty degree of the specific sample set based on the difficulty value of the specific sample;
s7, extracting samples in corresponding proportion from the class samples corresponding to the cloud sample set corresponding to the difficulty degree distribution condition in the specific sample set, and generating a sample subset;
and S8, training a coronary stenosis degree evaluation model by using the sample subset.
Further, in S1, the cloud sample set is generated based on the same model data, and samples in subsequent steps are extracted based on the same model data.
Further, the difficulty value is calculated by the following formula:
in the formula, M1 is the cloud score of the class where a specific sample is located, and M2 is the actual score of a specific sample.
The invention also discloses a coronary stenosis degree evaluation system, which comprises:
a cloud sample set acquisition module that collects samples from each hospital by a cloud method, the samples including raw scan data and stenosis degree scores to form a cloud sample set;
the cloud expert manually extracts samples from the cloud sample set through the human-computer interaction module, labels and classifies the samples, and meanwhile obtains cloud scores of all classified samples;
the system comprises a sample classification module, a data processing module and a data processing module, wherein an image classification model is arranged in the sample classification module and is trained on labeled classification samples;
a specific sample set collecting module which collects specific samples corresponding to a specific hospital or a specific expert in the hospital from the specific hospital to form a specific sample set and inputs the specific sample set into a sample classifying module for classification;
the specific sample evaluation module determines a difficulty value of the specific sample according to the difference between the actual score of the specific sample and the cloud score of the class of the specific sample based on the classification result; confirming the difficulty degree of the specific sample set based on the difficulty value of the specific sample;
the sample extraction module extracts samples in corresponding proportion from the class samples corresponding to the cloud sample set based on the difficulty degree distribution condition in the specific sample set to generate a sample subset;
a coronary stenosis degree evaluation module, which is internally provided with a coronary stenosis degree evaluation model, and the coronary stenosis degree evaluation model is trained based on the sample subset.
After adopting the technical scheme, compared with the background technology, the invention has the following advantages:
the method fully considers the differences of the evaluation strategies of different hospitals or different experts, evaluates and classifies the sample difficulty to obtain the difficulty degree distribution condition of the samples in a specific hospital, extracts the model training samples according to the difficulty degree distribution condition, enables the model training samples to accord with the grading habit of the specific hospital or the specific experts in the specific hospital, enables the grading result to be more referential, and improves the efficiency of doctors.
Drawings
FIG. 1 is a flow chart of a coronary stenosis degree evaluation model training method of the present invention;
fig. 2 is a block diagram of a coronary stenosis degree evaluation system according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are all based on the orientation or positional relationship shown in the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the apparatus or element of the present invention must have a specific orientation, and thus, should not be construed as limiting the present invention.
Example 1
Referring to fig. 1, the invention discloses a coronary stenosis degree evaluation model training method, which mainly includes 8 core steps.
S1, obtaining a cloud sample set: samples, including raw scan data and stenosis score, are collected from various hospitals by a cloud method to form a cloud sample set.
In consideration of differences generated by different model data, in S1, the cloud sample set is generated based on the same model data, that is, for the same model data, data of different hospitals may be mixed together to form a large data set, and samples in subsequent steps are extracted based on the same model data.
And S2, manually labeling and classifying the samples extracted from the cloud sample set and obtaining the cloud scores of the classified samples.
Collecting samples, manually classifying the samples based on image quality and the occurrence positions of the focuses, classifying the occurrence positions of the focuses and the similar image quality into one class, giving classification labels to the classes, and obtaining training samples. Meanwhile, one cloud score (i.e., a homogeneous score) may be generated for each classification sample. The cloud score may be an average score of the narrowness of each sample in the classified sample set, or may be a comprehensive score given by a cloud expert for the type of sample.
And S3, training an image classification model based on the labeled classification sample.
Through the processing of S2, the training samples are all images which are manually annotated whether the images are similar to certain types of images, and the image classification model can be trained and obtained by obtaining the 'stacking' annotation.
S4, obtaining a specific sample set and classifying: collecting specific samples corresponding to a certain hospital or a certain expert in the hospital from the certain hospital to form a specific sample set; and inputting the specific sample set into a classification model for classification.
The acquisition of the specific sample set can be performed by randomly drawing 100-200 specific samples corresponding to the hospital or a specific expert in the hospital in units of years, so that the specific samples relatively conform to natural distribution.
S5, determining the difficulty value of the specific sample: and determining the difficulty value of the specific sample according to the difference between the actual score of the specific sample and the cloud score of the class of the specific sample based on the classification result.
The concept of a difficulty value is derived from the actual score of a particular expert and the cloud score of that type of sample. The lower the score is, the closer the scoring habit representing the specific expert is to the cloud, the more consistent the scoring of different experts on the sample is, and the simpler the sample is represented; the higher the score is, the greater the difference between the scoring habit representing the specific expert and the cloud, and the more difficult the specific expert represents the sample because the strategies adopted by the specific expert are different in the scoring result of the sample.
The difficulty value is calculated by the following formula:
in the formula, M1 is the cloud score of the class where a specific sample is located, and M2 is the actual score of a specific sample.
And S6, confirming the difficulty degree of the specific sample set based on the difficulty value of the specific sample.
The difficulty level can be divided into a plurality of grades according to the sequence from easy to difficult.
For example, there are 8 samples. The difficulty values of the samples are respectively 32%, 35%, 48%, 60%, 62%, 69%, 70% and 78%, and the difficulty is divided into 4 grades, namely, one class is divided from 0-100% at intervals of 25%. Then 32%, 35%, 48% belong to the second category; 60%, 62%, 69%, 70% belong to the third category; 78% belong to the fourth category.
And S7, extracting samples in corresponding proportion from the class samples corresponding to the cloud sample set corresponding to the difficulty degree distribution condition in the specific sample set, and generating a sample subset.
For difficulty level 4, the distribution of easy-to-difficult in a particular sample set is 3: 3: 2: 2, the sample is extracted from the cloud sample set according to the ratio to generate the sample subset.
And S8, training a coronary stenosis degree evaluation model by using the sample subset.
Example 2
The invention also discloses a coronary stenosis degree evaluation system, which comprises:
a cloud sample set acquisition module that collects samples from each hospital by a cloud method, the samples including raw scan data and stenosis degree scores to form a cloud sample set;
the cloud expert manually extracts samples from the cloud sample set through the human-computer interaction module, labels and classifies the samples, and meanwhile obtains cloud scores of all classified samples;
the system comprises a sample classification module, a data processing module and a data processing module, wherein an image classification model is arranged in the sample classification module and is trained on labeled classification samples;
a specific sample set collecting module which collects specific samples corresponding to a specific hospital or a specific expert in the hospital from the specific hospital to form a specific sample set and inputs the specific sample set into a sample classifying module for classification;
the specific sample evaluation module determines a difficulty value of the specific sample according to the difference between the actual score of the specific sample and the cloud score of the class of the specific sample based on the classification result; confirming the difficulty degree of the specific sample set based on the difficulty value of the specific sample;
the sample extraction module extracts samples in corresponding proportion from the class samples corresponding to the cloud sample set based on the difficulty degree distribution condition in the specific sample set to generate a sample subset;
a coronary stenosis degree evaluation module, which is internally provided with a coronary stenosis degree evaluation model, and the coronary stenosis degree evaluation model is trained based on the sample subset.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.