JP2023045393A - Skin aging evaluation method using ultrasonic skin inside image - Google Patents

Abstract

To provide a skin aging degree evaluation method capable of highly accurately evaluating a relation between a skin and an age using an easily acquirable ultrasonic image of dermis of a skin.SOLUTION: A skin aging degree evaluation method is characterized by acquiring a ratio and/or difference calculated using an average luminance of an ultrasonic image of a dermis of a skin that can be easily and non-invasively acquired. The method of deriving a skin aging degree, capable of easily evaluating an aging state from structural density inside the dermis of the ultrasonic image of the skin, with due consideration of site differences and individual differences, the method acquires a ratio and/or a difference of the structural density inside the dermis by using a value calculated from two sides, a papillary dermis and a reticular dermis. Thereby, the skin aging degree evaluating method with due consideration of the site differences and individual differences can be provided by just using the ultrasonic image of the dermis of the skin.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a method for evaluating skin aging using internal skin images obtained noninvasively by ultrasound.

The skin is composed of three layers, the epidermis, the dermis and the subcutaneous tissue, from the outside. The dermis is rich in fibrous components such as collagen fibers and elastic elastin, and is greatly involved in the firmness and elasticity of the skin. Therefore, skin age is estimated using the structural density of these intradermal fiber components (Patent Documents 1 and 2). As for skin evaluation, in order to respond to the interest and desire to know one's own skin condition, that is, to know the skin condition as a beauty product, methods for analyzing the internal structure of the skin have evolved along with the evolution of imaging equipment that enables non-invasive evaluation of the inside of the skin. (Patent Document 3). Skin evaluation, which enables one to objectively know what kind of condition one's skin is in, is important as a means of responding to demands for beauty.

The structural density of the dermis is determined by analyzing changes in the brightness of images obtained non-invasively with various devices, by selecting an arbitrary part of the dermis, and using it to evaluate skin aging. However, since the dermis is subject to multiple effects such as natural aging and photoaging, it is difficult to say that the structural density of the dermis changes uniformly. In the dermis, due to aging and UV exposure, not only does the structural density decrease due to the decrease in fiber components such as collagen, but conversely, thick and short degenerated elastic fiber components such as elastin that increase the structural density also accumulate (Patent document 3, Non-Patent Documents 1, 2). In addition, since the structural density of the dermis is not uniform depending on the site, it also means that the information on the structural density of the dermis obtained depending on the image acquisition conditions varies greatly. Furthermore, there are individual differences in the initial state of the structural density of the dermis due to differences in the amount of collagen and elastin that are naturally present in the dermis. Therefore, in the conventional evaluation method, the proposal of the index of aging based on the image inside the skin obtained by ultrasound has improved the accuracy without considering the difference between sites and individuals (Patent Document 3). In addition, in order to perform skin evaluation that considers site differences and individual differences, it is necessary to propose a composite skin evaluation that combines internal skin images obtained by ultrasound with other skin physical property evaluations. It has been difficult to propose an aging index and skin evaluation that takes into consideration site differences and individual differences using only the obtained images of the inside of the skin (Patent Document 4).

Japanese Patent Laid-Open No. 11-290312 JP 2000-83954 JP 2012-235804 Special table 2012-501753

Relationship between hyaluronic acid degradation and wrinkle/sagging formation in photoaged skin, Solar UV Protection Research Committee Scientific Report, 9-13 (2018) Elastin fiber formation model by new dermis model, Journal of Japanese Cosmetic Technologists, 44(4), 278-284 (2010)

In view of this situation, in order to solve the above problems, the present invention provides a skin aging method that can accurately evaluate the relationship between skin and age using an ultrasonic image of the dermis inside the skin that can be easily obtained. It is to provide an evaluation method.

An object of the present invention is to provide a method for evaluating skin aging that can accurately evaluate the relationship between skin and age using an ultrasonic image of the dermis that can be obtained noninvasively and easily. . A method that can easily evaluate the aging state from ultrasonic images of the dermis of the skin while taking into account site differences and individual differences is a value calculated from the dermis internal structure density of the two parts, the papillary dermis and the reticular dermis. to be treated as ratios and/or differences. As a result, we have found a method for calculating the degree of skin aging that takes into consideration site differences and individual differences, using only ultrasound images, and have completed the present invention.

That is, the present invention is as follows.
(1) A method for evaluating the degree of skin aging from the dermal internal structure density of the skin,
(a) Ultrasonic waves are irradiated from the surface of the skin toward the inside of the skin, and the reflected waves of the ultrasonic waves reflected from the inside of the skin are detected by an ultrasonic tomography device to obtain an ultrasonic image of the inside of the skin. process,
(b) Select a certain area of the papillary dermis and reticular dermis from the ultrasonic image of the dermis portion of the skin obtained by the step (a), and average the intensity of the reflected waves of the ultrasonic waves in that certain area calculating luminance;
(c) a step of calculating the average luminance ratio and/or difference between the papillary dermis and the reticular dermis calculated in the step (b) and using it as an aging index;
A method for evaluating the degree of skin aging, including
(2) The method according to (1), wherein the skin site to be evaluated is the face.

The method for evaluating skin aging of the present invention enables quick and easy evaluation of skin aging using noninvasively obtained ultrasound images, and can be used in counseling and skin evaluation, such as beauty advice based on individual differences. be.

It is an example of the image of the cheek obtained from the ultrasonic tomography apparatus used by this invention. It consists of the epidermis, dermis, and subcutaneous tissue in this order from the left. The upper part of the image is the nose side, and the lower part of the image is the ear side.

FIG. 10 is an implementation diagram and a correlation coefficient showing the age of 98 women and the distribution of cheek dermis papillary layer average luminance/dermis reticular layer average luminance using ultrasound images;

Fig. 10 is a comparative diagram showing the average luminance distribution of the buccal dermis (from the papillary dermis to the reticular dermis) using age and ultrasound images of 98 women, and correlation coefficients.

FIG. 10 is a comparison diagram and a correlation coefficient showing the age of 98 women and the distribution of average brightness of the buccal dermis papillary layer using ultrasound images.

FIG. 10 is a comparative diagram showing the age of 98 women and the distribution of average brightness of the reticular layer of the cheek using ultrasound images, and the correlation coefficient.

FIG. 10 is a comparison diagram showing the age of 30 women and the distribution of papillary dermis average luminance/average reticular dermis luminance using ultrasound images, and a correlation coefficient. FIG.

FIG. 10 is a comparison diagram showing the age of 30 women and the distribution of the papillary dermis average luminance/average reticular dermis luminance distribution at the corner of the mouth using ultrasound images, and the correlation coefficient.

FIG. 10 is a comparison diagram and a correlation coefficient showing the age of 30 women and the distribution of average brightness of the buccal papillary layer using ultrasound images; FIG.

FIG. 10 is a comparison diagram showing the age of 30 women and the distribution of the average brightness of the dermal papillary layer at the corner of the mouth using ultrasound images, and the correlation coefficient.

FIG. 10 is a comparison diagram showing the age of 30 women and the distribution of average brightness of the reticular layer of the cheek using ultrasound images, and the correlation coefficient.

FIG. 10 is a comparison diagram showing the age of 30 females and the distribution of the average brightness of the reticular dermis at the corner of the mouth using ultrasound images, and the correlation coefficient.

FIG. 10 is an implementation diagram showing the age of 98 women, the distribution of the difference between the cheek dermis papillary layer average luminance and the cheek reticular dermis average luminance using ultrasound images, and the correlation coefficient.

FIG. 10 is a comparative diagram showing the age of 30 women and the distribution of the difference between the cheek dermis papilla layer average luminance and the cheek reticular dermis average luminance using ultrasound images, and the correlation coefficient.

FIG. 10 is a comparison diagram showing the age of 30 women and the distribution of the difference between the average brightness of the papillary dermis layer at the corner of the mouth and the average brightness of the reticular dermis layer at the cheek using ultrasound images, and the correlation coefficient.

The present invention will be described in further detail below.

The captured images used in the present invention are obtained by an ultrasonic tomography apparatus. The ultrasonic waves used in the ultrasonic tomography apparatus are selected from a frequency range of 20 to 75 MHz that can analyze the dermis of the skin. The skin internal image is obtained by irradiating selected ultrasonic waves perpendicularly to the internal direction of the skin, and detecting and imaging the ultrasonic waves (reflected waves) reflected from the inside of the skin with an ultrasonic tomography device. .

The photographed image used in the present invention may be an image of the dermis of the skin, preferably an exposed portion of the skin. For example, cheeks, corners of the mouth, face line, etc. can be changed depending on the purpose of measurement.

The analysis method of the present invention uses the above image to select a certain area of different parts in the depth direction of the dermis of the skin, and calculates the average luminance in that certain area. The different parts in the depth direction of the dermis refer to the papillary dermis, which is the uppermost layer of the dermis, and the reticular dermis, which is the lower part of the papillary dermis. The dermal papillary layer corresponds to the dermis side of the site where the papillae at the boundary between the epidermis and the dermis are forested, and is located at the top of the dermis. The reticular dermis is the lower layer of the dermis and borders the subcutaneous tissue. The dermis has an average thickness of about 2.0 mm, depending on the site. Among them, in order to distinguish between the papillary dermis and the reticular dermis so that they are not mixed, the papillary dermis to be analyzed is based on 0 mm directly below the boundary with the epidermis, and the range up to 0.5 mm in depth. is good. Preferably, the range is from 0 mm directly below the boundary with the epidermis to a depth of 0.35 mm. In addition, the reticular dermis to be analyzed should have a depth of 0.70 mm to 1.5 mm, with 0 mm directly below the boundary with the epidermis, excluding subcutaneous tissue. Preferably, the depth is in the range of 0.75 mm to 1.2 mm based on 0 mm directly below the boundary with the epidermis. In addition, the average luminance is calculated using the reflected wave when the ultrasonic waves irradiated into the skin are transmitted or reflected due to the difference in structural density inside the skin. It is obtained by averaging the intensity of reflected waves in a certain area. Although the area for calculating the average brightness is not particularly limited, it is preferably in the range of 1 mm ² to 15 mm ² . The site to be analyzed is selected from a site located in the depth of the papillary dermis and a site located in the depth of the reticular dermis. Using the average luminance calculated from a certain area of the papillary dermis and reticular dermis, the ratio of the average luminance of the papillary dermis to the reticular dermis in the dermis, or the difference obtained by subtracting the papillary dermis from the reticular dermis is further calculated. characterized by The calculated ratio or difference value is taken as the degree of aging. The degree of aging depends on the calculation method, but when expressed as the ratio of the average brightness of the papillary dermis to the reticular dermis, the smaller the value, the higher the degree of aging, and the difference is the subtraction of the papillary dermis from the reticular dermis. When expressing, the higher the numerical value, the higher the degree of aging. In the evaluation of the degree of skin aging, the ratio and/or the difference in average brightness between the papillary dermis and the reticular dermis may be used for different purposes.

Examples are given below to effectively explain the present invention. In addition, this invention is not limited by this.

For 98 female subjects, internal cheek skin images were acquired using an ultrasonic tomography apparatus, DermaScan (manufactured by Cortex Technology). In addition, for comparison of sites, internal images of the skin at the corners of the mouth were obtained from 30 female subjects. The region of the cheek where the image was acquired is the cheek region at the intersection of two lines drawn from the outer corner of the eye and the nostril, and the corner of the mouth is the region directly below the cheek region and lateral to the corner of the mouth. These two points were used for site comparison. Each image was analyzed by DermaScan software. For the papillary dermis, a constant area of 4.52 mm ² was selected as an analysis region within a depth range of 0 mm to 0.35 mm just below the boundary between the epidermis and dermis in the image. As for the reticular dermis, a constant area of 4.52 mm ² was selected as an analysis region within a depth range of 0.75 mm to 1.1 mm based on 0 mm immediately below the boundary between the epidermis and the dermis. For the average luminance of the entire dermis for comparison with the papillary dermis and reticular dermis, the range of depth from 0 mm to 1.1 mm just below the boundary between the epidermis and dermis in the image so as to include the papillary dermis and reticular dermis. A constant area of 13.6 mm ² was selected as an analysis region, and the average brightness of the entire dermis was calculated.

As a first analysis method, the average brightness (%) of each analysis area of the papillary dermis and reticular dermis for the cheek is calculated, and the average brightness is used to calculate the average brightness of the papillary dermis with respect to the reticular dermis. A ratio was calculated. Correlation with age was confirmed using this calculated ratio (Tables 1-2, Figures 2-5). For comparison, the same analysis method was used to calculate the average brightness (%) of the analysis regions of the papillary dermis and reticular dermis in the cheeks and corners of the mouth for 30 women. Using the average luminance, the average luminance ratio of the papillary dermis to the reticular dermis was calculated. Using this calculated ratio, the correlation with age was confirmed (Tables 1-2, Figures 6-11).

As a result, it was confirmed that the average luminance ratio of the papillary dermis and the reticular dermis in the cheek has a very high correlation with age and can be used as an index for evaluating the degree of skin aging. It was confirmed that the site for which the average brightness was calculated was the entire dermis alone or the reticular dermis alone, but no correlation was observed, and it did not serve as an index for evaluating the degree of skin aging (Tables 1 and 2, 3 and 5). In addition, in the case of the average luminance of only the papillary dermis, a correlation is observed when the number of target data is added from 30 to 98 (Tables 1 and 2, Fig. 4, Fig. 8). It was considered that the average brightness of only the layer was an index that should be considered for the need to improve the accuracy. On the other hand, the average luminance ratio of the papillary dermis to the reticular dermis maintains a high correlation with age for both 30 and 98 subjects, indicating a highly accurate degree of aging. (Tables 1 and 2, Figures 2 and 6).

In addition, at the corner of the mouth, no correlation was observed between age and the average brightness of the papillary dermis alone and the average brightness of the reticular dermis alone, but the average brightness ratio of the papillary dermis to the reticular dermis was used. However, a weak correlation with age was observed (Tables 1-2, Figures 7, 9 and 11). From this, it can be said that calculating the average luminance ratio of the papillary dermis to the reticular dermis from the average luminance of only the papillary dermis and only the reticular dermis is a method of increasing the accuracy of the index for evaluating the degree of aging. .

As a second analysis method, the average brightness (%) of each analysis area of the papillary dermis and reticular dermis for the cheek was calculated, and the average brightness was used to subtract the papillary dermis from the reticular dermis. A difference in average luminance (difference in average luminance=average luminance of reticular dermis-average luminance of papillary dermis) was calculated. Using this calculated difference, correlation with age was confirmed (Tables 1 and 2, Figures 12 and 13). For comparison, the same analysis method was used to calculate the average brightness (%) of the analysis regions of the papillary dermis and reticular dermis in the cheeks and corners of the mouth for 30 women. Using the average brightness, the difference in average brightness was calculated by subtracting the papillary dermis from the reticular dermis. Using this calculated difference, correlation with age was confirmed (Tables 1 and 2, Figures 13 and 14).

As a result, it was confirmed that in the cheek, the difference in average brightness obtained by subtracting the papillary layer from the reticular dermis had a very high correlation with age, and could serve as an index for evaluating the degree of skin aging. The difference in the average luminance obtained by subtracting the papillary layer from the reticular dermis maintains a high correlation with age for both 30 and 98 subjects, indicating a highly accurate degree of aging. (Tables 1 and 2, Figures 12 and 13).

At the corners of the mouth, no correlation was observed between the average brightness of the papillary dermis alone and the average brightness of the reticular dermis alone, but the difference in the average brightness obtained by subtracting the papillary dermis from the reticular dermis. Using , a weak correlation was observed with age (Tables 1-2, Figures 13-14). From this, subtracting the papillary dermis layer from the reticular dermis layer from the average brightness of the papillary dermis alone and the reticular dermis alone to calculate the difference in the average brightness is a method to improve the accuracy of the index for evaluating the degree of aging. It can be said that there is.

According to the present invention, it is possible to evaluate skin aging in consideration of site differences and individual differences with images obtained from ultrasonic tomography equipment, which is noninvasive to the skin. It is now possible to present accurate information on aging that is tailored to the individual through advice based on skin checks.

Claims (2)

A method for evaluating the degree of skin aging from the skin dermis structural density,
(a) Ultrasonic waves are irradiated from the surface of the skin toward the inside of the skin, and the reflected waves of the ultrasonic waves reflected from the inside of the skin are detected by an ultrasonic tomography device to obtain an ultrasonic image of the inside of the skin. process,
(b) Select a certain area of the papillary dermis and reticular dermis from the ultrasonic image of the dermis portion obtained in the step of (a), and calculate the average brightness from the intensity of the reflected wave of the ultrasonic wave in that certain area calculating
(c) a step of calculating the average luminance ratio and/or difference between the papillary dermis and the reticular dermis calculated in the step (b) and using it as an aging index;
A method for evaluating the degree of skin aging, including 2. The method of claim 1, wherein the site of skin to be evaluated is the facial area.

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