Lesion classification using skin patterning

Background/aims: The observation that skin line patterning tends to be disrupted by malignant but not non‐malignant skin lesions suggests that this could be used as an aid to lesion differentiation. Since recognised differentiating features can be obtained from the simply‐captured white light optical image, the possibility of using such images for skin pattern disruption detection is worth exploring. Methods: The skin pattern has been extracted from optical images by high‐pass filtering and profiles of local line strength variation with the angle estimated using a new consistent high‐value profiling technique. The resultant profile images have been analysed using a novel region‐based agglomerative clustering technique (mRAC) and also a local variance measurement. A measure based on the relationship between the classification results and an intensity‐based segmentation was calculated, and this represented the disruption of the skin line patterning. Results: A set of images containing a variety of histologically confirmed malignant and non‐malignant lesions was analysed. The computed textural disruption figure was compared to both the histological diagnosis and to a visual estimate of patterning disruption for each image. It was demonstrated that lesion separation could be achieved by both analysis methods, with a good correlation with visual estimate of disruption and with mRAC providing the best performance. Conclusions: It was concluded that the acquisition and modelling of skin line patterning from clinical images of skin lesions had been successfully achieved and that the analysis of the resulting data provided an assessment of pattern disruption that is both consistent with visual inspection and effective in presenting information useful for discrimination between melanoma and benign naevi lesion examples.     

Age-dependent changes in skin surface assessed by a novel two-dimensional image analysis

Background/purpose: Skin microrelief has been studied using various methods and devices. However, the long duration of time needed to process one sample or the expensive equipment hampered the use of those systems for routine diagnosis. Today, the emergence of new software and hardware technologies may allow this issue to be resolved.
Methods: To characterize objectively the skin surface, we introduced a new parameter SPm , namely, the area mean of superficial skin texture block formed by primary and secondary lines crossing each other. Based on the skin detector produced by the Boseview Technology Company, we developed a software for acquiring automatically skin images and calculating SPm . The relationship between SPm and age was studied on the dorsal and ventral midway of the forearm (sun-exposed and sun-protected areas) of 94 healthy volunteers without a history of smoking.
Results: The skin surface topography can be conveniently quantified with the new parameter SPm . The value of SPm of both sites increases with age, independent of sex, with the site more exposed to light being more affected.
Conclusion: With the software developed, the details of the skin surface can be observed. SPm appears to be a new valid parameter for characterizing the property of the skin surface. Our method, alone or in combination with other technologies of skin topography analysis may be applied in routine diagnosis for a quantified evaluation of skin aging.     

Measurement of skin texture through polarization imaging

Background Determination of skin surface texture is of particular importance in the field of dermatology as such measurements can be used for skin diagnostics and evaluation of therapeutic or cosmetic treatments. Profilometry of skin replicas, three‐dimensional imaging and computer vision have been successfully used to measure and document skin texture. Nevertheless, the development of a simpler and faster technique may prove to be advantageous in a clinical setting. Objectives We propose the use of polarization imaging with high angles of incidence as a simple alternative to measure/document skin texture/roughness. Methods A system based on digital photography and polarization optics was developed to acquire and compute texture images. Optimization of the system configuration was conducted to enhance the contrast for measuring skin roughness. The method was validated against roughness standards and tested in clinical studies. Measurements were made in subjects aged from 9 to 70 years and image analysis was used to evaluate texture. Results The developed texture scale was shown to correlate closely to the results from clinical assessment and from roughness standards. Frequency domain analysis showed a significantly different power spectrum for the texture images of young subjects when compared with older subjects. The evaluation of texture as a function of age showed that facial skin roughness increased linearly from teenage to 40 years followed by a plateau thereafter. Conclusions The system proved to be a useful clinical tool for assessing skin texture. The age‐related results may indicate that some skin texture features are formed before the age of 40 years.     

Skin texture parameters of the dorsal hand in evaluating skin aging in China

Background/purpose: There are various non‐invasive methods in skin morphology for assessing skin aging. The use of digital photography will make it easier and more convenient. In this study, we explored some skin texture parameters for evaluating skin aging using digital image processing. Methods: Two hundred and twenty‐eight subjects who lived in Sanya, China, were involved. Individual sun exposure history and other factors influencing skin aging were collected by a questionnaire. Meanwhile, we took photos of their dorsal hands. Skin images were graded according to the Beagley–Gibson system. These skin images were also processed using image analysis software. Five skin texture parameters, Angle Num., Angle Max., Angle Diff., Distance and Grids, were produced in reference to the Beagley–Gibson system. Results: All texture parameters were significantly associated with the Beagley–Gibson score. Among the parameters, the distance between primary lines (Distance) and the value of angle formed by intersection textures (Angle Max., Angle Diff.) were positively associated with the Beagley–Gibson score. However, there was a negative correlation between the number of grids (Grids), the number of angle (Angle Num.) and the Beagley–Gibson score. These texture parameters were also correlated with factors influencing skin aging such as sun exposure, age, smoking, drinking and body mass index. In multivariate analysis, Grids and Distance were mainly affected by age. But Angle Max. and Angle Diff. were mainly affected by sun exposure. Conclusion: It seemed that the skin surface morphologic parameters presented in our study reflect skin aging changes to some extent and could be used to describe skin aging using digital image processing.     

Digital image analysis for diagnosis of skin tumors

Between 1987 and 2007, different groups developed digital image analysis systems for the diagnosis of benign and malignant skin tumors. As the result of significant differences in the technical devices, the number, the nature and benign/malignant ratio of included skin tumors, different variables and statistical methods any comparison of these different systems and their results is difficult. For the use and comparison of the diagnostic performance of different digital image analysis systems in the future, some principle basic conditions are required: All used systems should have a standardized recording system and calibration. First, melanocytic and nonmelanocytic lesions should be included for the development of the diagnostic algorithms. Critical analyses of the results should answer the question if in future only melanocytic lesions should be analyzed or all pigmented and nonpigmented lesions. This will also lead to the answer if only dermatologists or all specialities of medical doctors will use such a system. All artifacts (eg, hairs, air bubbles) should be removed. The number of variables should be chosen according to the number of included melanomas. A high number of benign skin lesions should be included. Of all lesions only 10% or better less should be invasive melanomas. Each system should be developed by a training-set and controlled by an independent test-set. Each system should be controlled by the user with the final decision and responsibility and tested by independent users without any conflict of financial interest.     

主观皮肤类型与皮肤屏障功能的关系

目的:比较不同主观皮肤类型(油性、中性和干性皮肤)屏障功能指标的差异。方法:利用无创性方法对自评为油性、中性和干性皮肤的20~25岁北京城市女性(各30例)进行皮脂分泌率(SER)、角质层含水量、p H值和经皮肤水分丢失(TEWL)值的检测,并采用胶带连续粘脱后监测TEWL值变化的方法评价角质层完整性,采用角质层取样蛋白定量的方法评价角质层黏合力和丝氨酸蛋白酶活性。结果:主观皮肤类型为中性皮肤者具有最佳的屏障功能;干性皮肤和油性皮肤者面颊部的屏障功能均有不同程度的受损,表现为TEWL值明显升高、p H值升高、丝氨酸蛋白酶活性增加;但二者也有区别,油性皮肤者角质层完整性下降更明显,而干性皮肤主要是角质层黏合力明显减弱。结论:自评为油性和干性皮肤者与中性皮肤者相比,屏障功能均存在一定程度的缺陷,油性皮肤与干性皮肤均具有不同特点,且与其屏障受损的机制不同有关。     

Digital image analysis of facial erythema over time in persons with varied skin pigmentation

Background/purpose: Selected chemotherapeutic agents used for the treatment of cancer are known to cause skin toxicities. One group of agents, epidermal growth factor receptor (EGFR) inhibitors, characteristically precipitates an acneform rash. Currently, no standard of care exists for the management of the rash resulting from EGFR inhibitors. In order to objectively evaluate any management strategy, a method to quantify the rash is required. The purpose of this paper is to describe a method to quantify the erythema of a facial rash through the use of digital photography and image analysis. Methods: A Canfield OMNIA System using a Canon PowerShot Pro1 camera was used to obtain high‐resolution digital images of facial rashes. Digital images were recorded in Joint Photographic Experts Group format, corrected for brightness and white balance and color. A method was developed to analyze digital images of erythema independent of the range of skin pigmentation. Results: Two examples are given to illustrate the method developed and its utility. Conclusion: An inexpensive and portable method is described for objectively monitoring the development of facial erythema in subjects of the full range of skin pigmentation. This method can be used clinically to examine the development and resolution of facial rash erythema in response to treatment.     

Glove powder affects skin roughness, one parameter of skin irritation

Most patients with immediate-type-hyper sensitivity to natural rubber latex (NRL) give a history of hand eczema. Susceptibility to allergens is increased by irritant hand eczema due to damage to the skin barrier. Therefore, especially for employees in medical or paramedical professions, reduction in skin irritation is of importance. The present study reports the effect of glove powder on skin roughness, one feature of skin irritancy. Skin replicas, performed before and after wearing different types of gloves, were evaluated by laser profilometry. Significant alteration of skin roughness was evident and determined by different factors. Use of unpowdered Biogel gloves on prepowdered hands results in an increase in skin roughness, in contrast to the use of Biogel gloves on hands without any pre-application. On the other hand, powdered Manex neoderm gloves show no influence on the skin structure, whereas powdered Peha taft gloves also increase the roughness of the skin. Other potential candidates causing skin morphology alteration could be the glove pH, rubber chemicals with irritant potential and other characteristics of gloves, which are already under investigation.     

Computer recognition of skin structures using discriminant and cluster analysis

Background/aims: Automated image analysis of complex tissues is usually limited by the difficulty of recognizing special structures by computer. The aim of this study was to test the applicability of discriminant and cluster analysis to the interpretation of skin images.
Methods: Digital images from microscopic, dermatoscopic and clinical views of skin specimens were electronically dissected into elements of equal size and shape, and a set of grey level, colour and texture features was assessed for each element. Elements were classified interactively and submitted to discriminant analysis. Furthermore, hierarchical cluster analysis was used to enable the system to classify the tissue elements automatically, based on the available digital information. The classification results were relocated to the original image in order to evaluate the performance of the procedure.
Results: The system performs well in reproducibly detecting different skin structures in digital images. Discriminant analysis of interactively classified elements yielded a correct reclassification in 98 to 100% of tissue elements. Among the cluster analysis procedures, the conservative Ward method after removal of all highly correlated features produced the best results. The method turned out to be applicable irrespective of the image source used.
Conclusions: Discriminant and cluster analysis may be helpful techniques for a user-independent, subjectively unbiased measurement system of skin structures.     

Expression of transferrin receptor in normal human skin, psoriatic skin and various skin tumors

The distribution of transferrin receptor in normal human skin and its expression in psoriatic skin and various skin tumors have been investigated. Immuno-peroxidase staining was performed on biopsy specimens using monoclonal OKT 9 antibody, which reacts with transferrin receptor. Normal human skin showed positive staining with OKT 9 in eccrine glands and outer root sheaths of the hair. Sebaceous glands were also strongly positive. The basal layer stained very weakly. Psoriatic skin expressed OKT 9 strongly in the epidermis, especially in the area of the rete ridge. In squamous cell carcinoma, Bowen's disease, and malignant melanoma, a widespread and strong labelling reaction was found. Basal cell epithelioma and genital Paget's disease were partially and moderately positive in their staining pattern. No such positive staining pattern could be found in either nevus cell nevi or seborrhoic keratosis. These findings indicate that, in normal skin, transferrin receptor exists in eccrine glands, sebaceous glands, and outer root sheaths of the hair in greater amounts. High amounts of expression of this receptor in psoriatic epidermis and malignant tumors suggests that immunohistochemical demonstration of transferrin receptor parallels the proliferating activity of the tissue or tumor of the skin and may provide an useful aid for detecting such conditions.     

Two possible classifications of facial skin type by two parameters in Korean women: sebum excretion rate (SER) and skin surface relief (SSR)

Background/alms: Worldwide there are many skin care and makeup products intended to maintain good appearance or youthful skin. However consumers don't know which products are suitable for their skin because they don't know their skin type exactly. To solve this problem, this study suggests two possible classifications of facial skin type by using simple methods.
Methods: In 662 healthy volunteers, sebum excretion rate (SER) on the forehead and cheek, and skin surface patterns on the cheek were examined by using Sebutape® and skin replica, respectively.
Results: The measured SER values from the forehead were 0.06-4.56 ng/cm²/min and those from the cheek were 0.04-3.80 ng/cm²/min. From these data, five facial skin types were classified by SER: low SER type, medium SER type, high SER type, combination-1 SER type, and combination-2 SER type. Twelve facial skin types were also classified; they were determined by star formation (SF), primary lines (PL), secondary lines (SL) and pore size from magnified skin surface relief (SSR) of the cheek.
Conclusions: From this study, we suggest new classifications of skin types by SER and SSR. The SER and the parameters of skin surface texture (SF, PL, and SL) decreased with age and the pore size increased with age. Although these methods did not classify facial skin types perfectly, we were able to check consumer's facial skin types simply and more quickly.