A method for quantitative identification of aortic valve calcification based on echocardiography

Abstract

The present invention relates to a new ultrasonic method for quantitatively identifying aortic valve calcification, by first acquiring an echocardiogram to obtain an end-diastolic aortic short-axis section image, and then using image post-processing software to outline the boundaries of the valve and valve ring in the image, respectively, to obtain the average grayscale value of the valve leaflet region and the average grayscale value of the valve ring region, first subtracting the comparison baseline value from the average grayscale value of the valve leaflet region to obtain a first grayscale value, and then subtracting the comparison baseline value from the average grayscale value of the valve ring region to obtain a second grayscale value, and the first grayscale value is divided by the second grayscale value to obtain a ratio USGS, and the ratio USGS is a quantitative index for evaluating the degree of valve calcification. The method of the present invention can realize the quantitative evaluation of the degree of valve calcification by echocardiography, and the USGS value obtained by the method of the present invention is compared with the CT calcification integral CTGS value (gold standard), and the test results show that the USGS value and the CTGS value show a good positive correlation.

Description

[0001] The invention belongs to the technical field of medical detection, and in particular relates to a new ultrasonic method for quantitatively identifying aortic valve calcification. Background Art

[0002] With the rapid and sustained development of the economy and society and the accelerated aging of the urban population, the incidence of valvular heart disease in the population has been increasing year by year. Among various valvular heart diseases, aortic valve disease plays a vital role. Once patients with aortic valve disease experience chest pain, fainting, heart failure, etc., they will have a high mortality rate and a very high sudden death rate. Studies have shown that aortic valve calcification is an independent risk factor for aortic valve disease, and with the aging of China's population, the base number of people with aortic valve calcification is constantly increasing. It is particularly important to conduct early quantitative analysis of aortic valve calcification.

[0003] In the past, surgical aortic valve replacement (SAVR) was the surgical treatment of choice for patients with aortic valve disease. However, such patients are old, in poor general condition, have low cardiac function, and often have multiple underlying diseases. Therefore, about 30% of patients cannot tolerate conventional surgical thoracotomy. Compared with surgery under open heart vision, transcatheter aortic valve replacement (TAVR) has the advantages of being minimally invasive, convenient, with a short hospital stay and less damage to patients. Quantitative assessment of aortic valve calcification is of great significance for whether patients with aortic valve disease need surgical surgery, the choice of surgical method, surgical risk assessment, and the selection and positioning of artificial valve models. Currently, in echocardiograms, although strong valve echoes indicate calcification, it is impossible to quantify the calcification. The present invention provides a new technology that achieves quantification of valve calcification by post-processing echocardiograms. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a new ultrasonic method for quantitatively identifying aortic valve calcification. The method of the present invention can realize the quantitative evaluation of the degree of valve calcification by echocardiography, and the USGS value obtained by the method of the present invention is compared with the CT calcification score integral CTGS value (gold standard). The test results show that the USGS value and the CTGS value show a good positive correlation.

[0005] The technical solution of the present invention is:

[0006] A novel ultrasound method for quantitatively identifying aortic valve calcification comprises the following steps:

[0007] (1) Acquire echocardiogram to obtain the short-axis section image of the aorta at the end of diastole;

[0008] (2) Using image post-processing software, the boundaries of the valve and annulus in the image are delineated respectively to obtain the average grayscale value of the valve region and the average grayscale value of the annulus region;

[0009] (3) First, the average grayscale value of the valve area is subtracted from the comparison baseline value to obtain a first grayscale value, and then the average grayscale value of the valve ring area is subtracted from the comparison baseline value to obtain a second grayscale value. The first grayscale value is divided by the second grayscale value to obtain a ratio USGS, which is a quantitative indicator for evaluating the degree of valve calcification.

[0010] In step (3), the comparison baseline value is the average gray value of the echo-free area.

[0011] The larger the USGS value, the higher the degree of valve calcification.

[0012] When USGS is less than 0.43, the degree of valve calcification is mild calcification.

[0013] When 0.43≤USGS≦0.91, the degree of valve calcification is moderate calcification.

[0014] When USGS>0.91, the degree of valve calcification is severe calcification.

[0015] In step (1), the echocardiogram is obtained using Philips ultrasonic diagnostic instrument EPIQ7c, EPIQ7 or CX50.

[0016] In step (1), the image is a two-dimensional grayscale image.

[0017] In step (2), the image post-processing software is Image J or Photoshop.

[0018] The beneficial effects of the present invention are:

[0019] The present invention provides a new ultrasonic method for quantitatively identifying aortic valve calcification, by first acquiring an echocardiogram to obtain an end-diastolic aortic short-axis section image, and then using image post-processing software to outline the boundaries of the valve and valve ring in the image, respectively, to obtain the average grayscale value of the valve leaflet region and the average grayscale value of the valve ring region, first subtracting the contrast baseline value from the average grayscale value of the valve leaflet region to obtain a first grayscale value, and then subtracting the contrast baseline value from the average grayscale value of the valve ring region to obtain a second grayscale value, and the first grayscale value is divided by the second grayscale value to obtain a ratio USGS, which is a quantitative index for evaluating the degree of valve calcification. The method of the present invention can realize the quantitative evaluation of the degree of valve calcification by echocardiography, and the USGS value obtained by the method of the present invention is compared with the CT calcification integral CTGS value (gold standard), and the test results show that the USGS value and the CTGS value show a good positive correlation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 The display is a conventional two-dimensional grayscale image acquired using the Philips ultrasound diagnostic instrument CX50;

[0022] Figure 2 Shown is a scatter plot of the corresponding USGS values ​​and CTGS values. DETAILED DESCRIPTION

[0023] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0024] The above technical solution is described in detail below in conjunction with specific embodiments.

[0025] Example 1

[0026] This embodiment provides a new ultrasound method for quantitatively identifying aortic valve calcification, comprising the following steps:

[0027] (1) Using Philips CX50 ultrasound diagnostic instrument to acquire echocardiogram, obtain the short-axis section image of the aorta at the end of diastole; Figure 1 As shown;

[0028] (2) First, use Image J to outline the border of the valve in the image, and the average grayscale value of the leaflet area is 97; then use Image J to outline the border of the valve ring in the image, intercept the valve ring image, and the average grayscale value of the valve ring area is 175;

[0029] (3) The average gray value of the leaflet region and the average gray value of the annulus region were subtracted from the average gray value of the anechoic region, where the average gray value of the anechoic region was 50, to remove the influence of different gains on the gray value of the ultrasound image. The ratio USGS was calculated by substituting (average gray value of the leaflet region - average gray value of the anechoic region) / (average gray value of the annulus region - average gray value of the anechoic region) into (97-50) / (175-50) to obtain a ratio of 0.38. The ratio USGS was used to quantitatively evaluate the degree of valve calcification.

[0030] In order to detect the correlation between the USGS obtained by the method of the present invention and the CT calcification score CTGS value (currently the gold standard for evaluating valve calcification), the following verification was performed:

[0031] A total of 62 patients with confirmed aortic valve calcification on cardiac enhanced CT were selected (ie, the average Hu value of more than three adjacent pixels on the aortic valve leaflet was 100 Hu larger than the average Hu value of the non-calcified area of ​​the ascending aorta).

[0032] Standard method for judging the severity of aortic valve calcification: Import the patient's cardiac enhanced CT image into the 3mensioValves software to analyze and calculate the CT aortic valve calcification score. Set the threshold to 850, and use the software to calculate the calcification of all valve leaflets. Generally, a calcification score of less than 400 is mild calcification, 400-800 is moderate calcification, and greater than 800 is severe calcification. The higher the score, the higher the degree of calcification. The CT valve calcification score is abbreviated as CTGS, and the corresponding CTGS of the patient in Example 1 is 362.

[0033] The ultrasound aortic valve calcification images of the above 62 patients were retrieved, and the aortic short-axis section images were obtained at the end of diastole. The (mean gray value of the leaflet area - the mean gray value of the echo-free area) / (mean gray value of the annulus area - the mean gray value of the echo-free area) was calculated by Photoshop or Imaging J software, which is the USGS. The USGS of the patient in Example 1 was 0.38.

[0034] The USGS values ​​of the 62 patients were matched with the CTGS values, and a scatter plot was drawn to fit the regression line. At the same time, a paired t-test was performed to determine that USGS and CTGS were positively correlated. Table 1 shows the specific values ​​of USGS and CTGS of the 62 patients.

[0035] Table 1-USGS and CTGS values ​​of 62 patients

[0036]

[0037]

[0038]

[0039] like Figure 2 As shown in the figure, it can be seen that through the intergroup comparison of 62 patients, USGS and CTCS have a good positive correlation. The degree of valve calcification can be evaluated by USGS. The larger the value, the higher the degree of valve calcification. At the same time, the threshold value was initially obtained. When USGS < 0.43, it is mild calcification; when 0.43 ≤ USGS ≦ 0.91, it is moderate calcification; USGS > 0.91 is severe calcification.

[0040] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for quantitatively identifying aortic valve calcification based on echocardiography, characterized in that: The following steps are involved: (1) Acquire echocardiogram to obtain the short-axis section image of the aorta at the end of diastole; (2) Using image post-processing software, the boundaries of the valve and annulus in the image were outlined to obtain the average grayscale value of the valve area and the average grayscale value of the annulus area; (3) First, the average gray value of the valve area is subtracted from the comparison baseline value to obtain a first gray value, and then the average gray value of the valve ring area is subtracted from the comparison baseline value to obtain a second gray value. The first gray value is divided by the second gray value to obtain a ratio USGS, which is a quantitative index for evaluating the degree of valve calcification; The comparison baseline value is the average gray value of the echo-free area.

2. The method for quantitatively identifying aortic valve calcification based on echocardiography according to claim 1, characterized in that: The larger the USGS value, the higher the degree of valve calcification.

3. The method for quantitatively identifying aortic valve calcification based on echocardiography according to claim 1, characterized in that: When USGS is less than 0.43, the degree of valve calcification is mild calcification.

4. The method for quantitatively identifying aortic valve calcification based on echocardiography according to claim 1, characterized in that: When 0.43≤USGS≦0.91, the degree of valve calcification is moderate calcification.

5. The method for quantitatively identifying aortic valve calcification based on echocardiography according to claim 1, characterized in that: When USGS>0.91, the degree of valve calcification is severe calcification.

6. The method for quantitatively identifying aortic valve calcification based on echocardiography according to claim 1, characterized in that: In step (1), the echocardiogram is obtained using Philips ultrasonic diagnostic instrument EPIQ7c, EPIQ7 or CX50.

7. The method for quantitatively identifying aortic valve calcification based on echocardiography according to claim 1, characterized in that: In step (1), the image is a two-dimensional grayscale image.

8. The method for quantitatively identifying aortic valve calcification based on echocardiography according to claim 1, characterized in that: In step (2), the image post-processing software is Image J or Photoshop.

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