|Year : 2015 | Volume
| Issue : 2 | Page : 79-82
An easy method to evaluate the therapeutic effects of laser therapy on port-wine stains based on DC images
Limin Ma1, Xiangdong Qi1, Jianzeng Qin2, Shizhen Zhong3, Ye Zhou1, Bin Zhang1
1 Department of Laser and Plastic Surgery, Liu Hua Qiao Hospital, Guangzhou, Guangdong Province, China
2 Center for Faculty Development, Southern Medical University, Guangzhou, Guangdong Province, China
3 Institute of Clinical Anatomy, Southern Medical University, Guangzhou 510010, Guangdong Province, China
|Date of Web Publication||25-Jan-2016|
Center for Faculty Development, Southern Medical University, Guangzhou 510010, Guangdong Province
Department of Laser and Plastic Surgery, Guangzhou General Hospital of Guangzhou Milltary Command, No. 111, Liuhua Road, Guangzhou 510010, Guangdong Province
Source of Support: None, Conflict of Interest: None
Objective: To investigate the treatment effects on port-wine stains (PWSs) using the red, green, and blue (RGB) color measuring and analyzing system in combination with a personal computer. Methods: Twenty patients with PWSs were evaluated both by the RGB color measuring and analyzing system and by the experienced plastic surgeons through a blind test. Then, the two treatment effects were compared. Results: The mean treatment effect was 51.6 ± 24% by RGB method, ranging from 2% to 98%, and that of the clinician evaluation was 47.13 ± 24.6%, ranging from 15% to 90%. There was no significant difference in treatment effects as evaluated by both the clinicians and the RGB measuring and analyzing system method on average (P > 0.05). The subjective clinical grades correlated well with the treatment effects obtained by the proposed computer-assisted RGB measuring and analyzing system (correlation coefficient, 0.87). Conclusions: RGB color measure and analysis system could replace clinician for the evaluation of treatment effects on PWSs and it is an easy, objective, quantitative, and cost-effective method, and can be useful for the evaluation of treatment effects on PWSs.
Keywords: Computer-assistance, port-wine stains, red, green and blue, treatment effects
|How to cite this article:|
Ma L, Qi X, Qin J, Zhong S, Zhou Y, Zhang B. An easy method to evaluate the therapeutic effects of laser therapy on port-wine stains based on DC images. Digit Med 2015;1:79-82
|How to cite this URL:|
Ma L, Qi X, Qin J, Zhong S, Zhou Y, Zhang B. An easy method to evaluate the therapeutic effects of laser therapy on port-wine stains based on DC images. Digit Med [serial online] 2015 [cited 2019 Jul 15];1:79-82. Available from: http://www.digitmedicine.com/text.asp?2015/1/2/79/174771
| Introduction|| |
Port-wine stains (PWSs) are common congenital capillary malformations that involve the capillaries of the dermis or subcutaneous tissue. As for its treatment, the long pulsed dye laser (PDL) that selectively targets oxyhemoglobin within the skin is considered as optimal, but it may cause damage to dermal blood vessels , while the PDL is regarded as safe and effective. , The assessment of the treatment outcome is necessary for PWSs. A number of noninvasive in vivo techniques, such as laser Doppler flowmetry, reflectance spectrophotometry, L*a*b* method, and colorimetry, have been developed to objectively measure PWSs patients' response to laser therapy. , These techniques cannot replace the clinical assessment by doctors and patients, for that they only assess the color of PWSs sites. The evaluation results lack objectivity and it is not an easy communication between doctor and patient. Furthermore, these techniques fail to calculate the area of lesions accurately. Therefore, an objective measurement of the color and area would be essential for predicting and monitoring the outcomes of PWSs by laser therapy.
Our aim was to develop a new method to assess the therapeutic effects of PWSs treatment quantitatively by comparing pre- and post-treatment digital images processed by red, green, and blue (RGB) color coordinates, which are widely used in color analysis.
| Methods|| |
Twenty patients (mean age: 20.25 years; 10 male and 10 female) with PWSs participated in this study. Their lesions were located on the face, neck, back, and so on.
All kinds of color in nature can be decomposed to three base colors: RGB (0, 0, 0) represents white and (255, 255, 255) black. Digital camera and computer display pictures by three basic colors. A computer screen is constructed by pixel. Through calculating the pixel, we can know the area of PWSs. The digital camera will show different colors with the different rates of RGB. The sum of RGB divided by 255 shows the different gray scale. Digital camera and computer monitor display colors by assigning different RGB values.
In our study, the pictures were taken by a digital camera (Nikon D300) with a charge coupled device with a resolution of 3872 × 2592. The digital photographs were transferred to a computer loaded with RGB color measuring and analyzing system. The focal length, shutter speed, aperture value, and ISO number of pre- and post-treatment images were uniform [Figure 1]. We manually selected PWSs sites to evaluate the treatment effect. A stood for pretreatment lesion; B for pretreatment normal skin; A' for posttreatment lesion; B' for posttreatment normal skin. The colors of both the lesions and the normal control skin adjacent to the lesions were evaluated before and after the treatment with the self-developed color analysis software program. We propose a new equation for calculating the therapeutic effects as follows:
|Figure 1: Patient with port-wine stains on the left side of the face. (a) Pretreatment R: 8.08%; G: −2.6%; B: −5.48%; Gray: −8.59%; Area: 42.89 cm2. (b) Posttreatment R: 5.49%; G: −77%; B: −4.72%; Gray: −9.77%; Area: 22.75 cm2|
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Six experienced plastic surgeons blinded to each DC Image of PWSs posttreatment effect. They were asked to evaluate the treatment effects by percentage, ranging from 0% indicating no effect to 100% indicating complete recovery. The therapeutic effects were classified into five categories: (1) Excellent (at least above 80%; the color of all the PWSs sites is similar to that of the normal skin); (2) good (60-79%; the color of most PWSs sites is similar to that of the normal skin); (3) fair (40-59%; the color of half the PWSs sites is similar to that of the normal skin); (4) poor (20-39%; the color of a few PWSs sites is similar to that of the normal skin); and (5) no response (lower than 19%; the color of several PWSs sites is similar to that of the normal skin). 
The pre- and post-treatment digital images of 20 patients with PWSs were evaluated both with the color analysis system and by the six experienced plastic surgeons through a blind test.
Data were presented as mean ± standard error of the mean using the SPSS version 13.0 Software (SPSS, Southern Medical University, China). Statistical analysis was performed using the independent sample test. The value P < 0.05 indicated statistical significance. In 20 patients with PWSs, the mean values of the curation were effects evaluated by the clinicians and the RGB color measuring and analyzing system. We also calculated Spearman's rho correlation coefficients of the treatment effects between the clinicians and the color analysis system.
| Results|| |
The mean treatment effect was 51.6 ± 24% by RGB method, ranging from 2% to 98%, and that of the clinician evaluation was 47.13 ± 24.6%, ranging from 15% to 90%. There was no statistically significant difference in the treatment effects as evaluated by both the clinicians and the RGB measuring and analyzing system method on average (P = 0.562). The correlation coefficient between the RGB measuring and analyzing system method and experienced clinicians' visual estimation was 0.87. Pre- and post-treatment computer-aided analysis report for every PWSs patient is shown in [Table 1] and classification of the treatment effects of PWSs is shown in [Table 2].
|Table 2: Classification of treatment effects of port-wine stains into five categories by red, green, and blue method and six clinicians both on average (n=20)|
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| Discussion|| |
Digital imaging, a convenient method of recording the appearance of a lesion at a given time, allows the comparison of the treatment effects on lesions such as PWSs. Traditional methods measure the color directly. Reflectance spectrophotometry can be susceptible to "lateral diffusion error," whereby some light that penetrates the surface of the skin is reflected from the inside of the skin, but cannot be detected by the integrating sphere. Laser Doppler flowmetry is sensitive to medications, gas stimulants, temperature change, and toxic gases, so it is limited in conducting multiple analysis of the lesion.  Tristimulus Colorimetry (Minolta, Osaka, Japan), a tool which measures the L*a*b* color parameters, can quantify color values,  but it is expensive and also prone to skin surface contact errors.  PWSs were measured using L*a*b* color coordinates, but it cannot accurately measure the size of areas for PWSs. RGB measuring and analyzing system demonstrated the potential as an investigative tool for PWSs assessment.
There are some subjective and qualitative evaluations of the treatment effects on PWSs. Widdowson et al.  constructed a novel PWSs phantom and measurement of color by digital imaging and reflectance spectrophotometry. The results show that skin phantom can be an investigative tool for color assessment. PWSs performed effective treatment using the L*a*b* color classification system assessment. Rah et al. showed a closer correlation with the physician's score than all other indices, yielding a Spearman's rank correlation coefficient of 0.89. 
Widdowson et al.  designed phantoms which primarily suggest the relationship between color and depth of blood within human PWSs skin. Color varies considerably as the depth of vasculature within the skin is varied.  This is described by a linear relationship between hue and the depth of the blood layer within the samples (R 2 = 0.99). Hue is an intuitive method of describing color, as it corresponds to the process whereby humans describe and perceive a visualized color. In this study, as the depth of the blood layer in the models increased, the hue was seen to change from near pure red to purple. 
The clinical experiments suggest that robot-assisted PDT treatment of PWSs can reduce the possibility of skin burns by improving the uniformity of laser irradiation. Such treatment may release doctors from repetitive manual work. Therefore, the development and clinical application of the robot system is useful in assisting doctors in the treatment of PWSs. 
| Conclusions|| |
RGB color measure and analysis system demonstrates a useful tool to evaluate the treatment effects of PWSs. The method provides an objective, accurate, quantitative, and cost-effective way of accessing the clinical PWSs.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
The work was supported by the National Natural Science Foundation of China (Grant No. 41271153), the National High Technology Research and Development 863 Program of China (Grant No. 2012AA021105) and the Special Project on the Integration of Industry, Education and Research of Guangdong Province, China (Grant No. 2012B091100472), Scientific and Technological Projects of Guangdong Province (No. 2013B010406007, 2015A030313608).
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]