Quantification of erythema using digital camera and computer-based colour image analysis: a multicentre study

The dose response of erythemal area and intensity on the unprotected skin fits well to a logistic 3P model in SPF tests of a Chinese population, which has the potential to improve the precision and consistency of minimal erythema dose determination

BACKGROUND

The current ISO guidelines for minimal erythema dose (MED) determination require assessment of erythema area of UV-irradiated skin sites. However, this parameter has not been adequately quantified in daily practice. The aims of this study were to investigate the dose response on the unprotected skin sites by quantifying the erythema area and intensity and to show the potential for improving the precision and consistency of MEDu determination by developing predictive models.

METHODS

Standard radiation tests were conducted on the back of 31 healthy Chinese volunteers and the MEDu site of each subject was clinically determined by dermatologists. Images of test sites were captured 24 h after radiation, and the erythema area (%EA) and intensity (∆a*) were measured by image analysis. The data were fitted to a logistic 3P function to obtain dose-response curves, and a set of logit (inverse-logistic) models were then derived. An erythema area threshold of %EA = 52% was established to predict MEDu based on the clinical endpoints defined by ISO 24444:2019.

RESULTS

Analysis of the clinically determined MEDu sites revealed wide ranges of %EA (62.3 ± 15% SD) and ∆a* (2.96 ± 0.92 SD). The dose response fitted well to a logistic 3P model (mean R2  = 0.965 and 0.975 for %EA and ∆a*, respectively). Applying the area threshold, values of MEDu were determined by the logit model for the test population, which significantly improved the consistency of MEDu determination (52 ± 0% SD and 2.73 ± 0.61 SD for %EA and ∆a*, respectively).

CONCLUSION

This study demonstrated that the dose response of UV-induced erythema can be quantified and modeled once the erythema area and intensity are measured. The results of this study show the potential to improve the precision and consistency of MEDu determination in an SPF test. The similar potential in photodermatological, therapeutic, and diagnostic applications was also implied.

An intelligent non-invasive system for automated diagnosis of anemia exploiting a novel dataset

Anemia is a condition in which the oxygen-carrying capacity of red blood cells is insufficient to meet the body's physiological needs. It affects billions of people worldwide. An early diagnosis of this disease could prevent the advancement of other disorders. Traditional methods used to detect anemia consist of venipuncture, which requires a patient to frequently undergo laboratory tests. Therefore, anemia diagnosis using noninvasive and cost-effective methods is an open challenge. The pallor of the fingertips, palms, nail beds, and eye conjunctiva can be observed to establish whether a patient suffers from anemia. This article addresses the above challenges by presenting a novel intelligent system, based on machine learning, that supports the automated diagnosis of anemia. This system is innovative from different points of view. Specifically, it has been trained on a dataset that contains eye conjunctiva photos of Indian and Italian patients. This dataset, which was created using a very strict experimental set, is now made available to the Scientific Community. Moreover, compared to previous systems in the literature, the proposed system uses a low-cost device, which makes it suitable for widespread use. The performance of the learning algorithms utilizing two different areas of the mucous membrane of the eye is discussed. In particular, the RUSBoost algorithm, when appropriately trained on palpebral conjunctiva images, shows good performance in classifying anemic and nonanemic patients. The results are very robust, even when considering different ethnicities.

Prediction of anemia using facial images and deep learning technology in the emergency department

Background

According to the WHO, anemia is a highly prevalent disease, especially for patients in the emergency department. The pathophysiological mechanism by which anemia can affect facial characteristics, such as membrane pallor, has been proven to detect anemia with the help of deep learning technology. The quick prediction method for the patient in the emergency department is important to screen the anemic state and judge the necessity of blood transfusion treatment.

Method

We trained a deep learning system to predict anemia using videos of 316 patients. All the videos were taken with the same portable pad in the ambient environment of the emergency department. The video extraction and face recognition methods were used to highlight the facial area for analysis. Accuracy and area under the curve were used to assess the performance of the machine learning system at the image level and the patient level.

Results

Three tasks were applied for performance evaluation. The objective of Task 1 was to predict patients' anemic states [hemoglobin (Hb) <13 g/dl in men and Hb <12 g/dl in women]. The accuracy of the image level was 82.37%, the area under the curve (AUC) of the image level was 0.84, the accuracy of the patient level was 84.02%, the sensitivity of the patient level was 92.59%, and the specificity of the patient level was 69.23%. The objective of Task 2 was to predict mild anemia (Hb <9 g/dl). The accuracy of the image level was 68.37%, the AUC of the image level was 0.69, the accuracy of the patient level was 70.58%, the sensitivity was 73.52%, and the specificity was 67.64%. The aim of task 3 was to predict severe anemia (Hb <7 g/dl). The accuracy of the image level was 74.01%, the AUC of the image level was 0.82, the accuracy of the patient level was 68.42%, the sensitivity was 61.53%, and the specificity was 83.33%.

Conclusion

The machine learning system could quickly and accurately predict the anemia of patients in the emergency department and aid in the treatment decision for urgent blood transfusion. It offers great clinical value and practical significance in expediting diagnosis, improving medical resource allocation, and providing appropriate treatment in the future.

Skin erythema assessment techniques

Skin erythema may present owing to many causes. One of the common causes is prolonged exposure to sunrays. Other than sun exposure, skin erythema is an accompanying sign of dermatologic diseases, such as psoriasis and acne. Quantifying skin erythema in patients enables the dermatologist to assess the patient's skin health. Quantitative assessment of skin erythema has been the focus of several studies. The clinical standard for erythema evaluation is visual assessment; however, this standard has some deficiencies. For instance, visual assessment is subjective and ineffectual for precise color information exchange. To overcome these limitations, in the past three decades various methodologies have been developed in an attempt to achieve objective erythema assessments, such as diffuse reflectance spectroscopy and both optical and nonoptical systems. This review considers the studies published during the past three decades and discusses the performance, the mathematical tactics for computation, and the limited capabilities of erythema assessment techniques for cutaneous diseases. The achievements and limitations of the current techniques in erythema assessment are presented. The advantages and development trends of optical and nonoptical methods are presented to make the reader aware of the present technological advances and their potential for dermatological disease research.

Hyperspectral imaging assessment for radiotherapy induced skin-erythema: Pilot study

Skin cancer (SC) is a widely spread disease in the USA, Canada, and Australia. Skin cancer patients may be treated by many different techniques including radiation therapy. However, radiation therapy has side effects, which may range from skin erythema to skin necrosis. As erythema is the early evidence of exposure to radiation, monitoring erythema is important to prevent more severe reactions. Visual assessment (VA) is the gold standard for evaluating erythema. Nevertheless, VA is not ideal, since it depends on the observer's experience and skills. Digital photography and hyperspectral imaging (HSI) are optical techniques that provide an opportunity for objective assessment of erythema. Erythema indices were computed from the spectral data using Dawson's technique. The Dawson relative erythema index proved to be highly correlated (97.1 %) with clinical visual assessment scores. In addition, on the 7th session of radiation therapy, the relative erythema index differentiates with 99 % significance between irradiated and non-radiated skin regions. In this study, HSI is compared to digital photography for skin erythema statistical classification.

Skin erythema and pigmentation: a review of optical assessment techniques

BACKGROUND

Skin erythema may present due to many causes. One of the common causes is prolonged exposure to sun rays. Other than sun exposure, skin erythema is an accompanying sign of dermatological diseases such as acne, psoriasis, melasma, post inflammatory hyperpigmentation, fever, as well as exposure to specific electromagnetic wave bands.

METHODS

Quantifying skin erythema in patients enables the dermatologist to assess the patient's skin health. Therefore, quantitative assessment of skin erythema was the target of several studies. The clinical standard for erythema evaluation is visual assessment. However, the former standard has some imperfections. For instance, it is subjective, and unqualified for precise color information exchange. To overcome these shortcomings, the past three decades witnessed various methodologies that aimed to achieve erythema objective assessment, such as diffuse reflectance spectroscopy (DRS), and both optical and non-optical systems.

DISCUSSION

This review article reports on the studies published in the past three decades where the performance, the mathematical tactics for computation, and the capabilities of erythema assessment techniques for cutaneous diseases are discussed. In particular, the achievements and limitations of the current techniques in erythema assessment are presented.

CONCLUSION

The profits and development trends of optical and non-optical methods are displayed to provide the researcher with awareness into the present technological advances and its potential for dermatological diseases research.

Imaging reveals distinct textures at three infant skin sites and reflects skin barrier status

BACKGROUND

Infant diaper dermatitis (DD) is a prevalent condition due to multiple, interactive factors including increased skin hydration, irritant exposure, and increased skin pH. We examined diaper dermatitis vs within diaper and non-diaper controls over time and characterized the association of skin color and texture relative to skin barrier integrity, hydration, and pH.

MATERIALS AND METHODS

The prospective study included 46 infants with DD at well-child visits. Skin integrity was evaluated over 15 days, including visual skin condition, rate of stratum corneum transepidermal water accumulation, hydration, pH, and skin color and texture from high-resolution digital skin surface images. Effects by site and time were evaluated with general linear models.

RESULTS

Six distinct texture patterns were observed. All three sites differed significantly for texture class frequency. Normal dermatoglyphics were more frequent for non-diaper vs both within diaper and rash sites. Dermatoglyphics with marked furrows or lines (class 3) were common within diaper vs rash but not for non-diaper vs within diaper. Streaks were highest for DD and lowest for non-diaper. Flat regions were more frequent DD. Barrier integrity, that is, moisture accumulation rate, was lower for normal dermatoglyphics than streaks or flat texture. DD severity decreased over 15 days. Barrier properties of within diaper and non-diaper areas were not well-differentiated.

CONCLUSION

The incidence of streak texture in the within diaper high magnification images was high despite being visually normal. This finding suggests that it is an "early indicator" of skin damage and may be clinically useful for early detection and treatment.

Objective evaluation of immediate reading skin prick test applying image planimetric and reaction thermometry analyses

The skin prick test is used to diagnose patients' sensitization to antigens through a mediated IgE response. It is a practical and quick exam, but its diagnosis depends on instruments for measuring the allergic response and observer's interpretation. The conventional method for inferring about the allergic reaction is performed from the dimensions of the wheals, which are measured using a ruler or a caliper. To make this diagnosis less dependent on human interpretation, the present study proposes two alternative methods to infer about the allergic reaction: computational determination of the wheal area and a study of the temperature variation of the patient's skin in the puncture region. For this purpose, prick test using histamine was performed on 20 patients randomly selected. The areas were determined by the conventional method using the dimensions of the wheals measured with a digital caliper 30 min after the puncture. The wheal areas were also determined by a Python algorithm using photographs of the puncture region obtained with a smartphone. A variable named circularity deviation was also determined for each analyzed wheal. The temperature variation was monitored using an infrared temperature sensor, which collected temperature data for 30 min. All results were statistically compared or correlated. The results showed that the computational method to infer the wheal areas did not differ significantly from the areas determined by the conventional method (p-value = 0.07585). Temperature monitoring revealed that there was a consistent temperature increase in the first minutes after the puncture, followed by stabilization, so that the data could be adjusted by a logistic equation (R² = 0.96). This adjustment showed that the optimal time to measure the temperature is 800 s after the puncture, when the temperature stabilization occurs. The results have also shown that this temperature stabilization has a significant positive correlation with wheal area (p-value = 0.0015). Thus, we concluded that the proposed computational method is more accurate to infer the wheal area when compared to the traditional method, and that the temperature may be used as an alternative parameter to infer about the allergic reaction.

The relationship between pressure offloading and ischial tissue health in individuals with spinal cord injury: An exploratory study

Objectives: To compare thickness and texture measures of tissue overlying the ischial region in able-bodied (AB) individuals vs. individuals with spinal cord injury (SCI) and to determine if there is a relationship between pressure offloading of the ischial tuberosities (IT) and tissue health in individuals with SCI. Design: Exploratory cross-sectional study. Setting: University setting and rehabilitation hospital. Outcome Measures: Thickness and texture measurements from ultrasound images of tissues overlying the IT were obtained from AB individuals (n = 10) and individuals with complete or incomplete traumatic and non-traumatic SCI American Spinal Injury Association Impairment Scale (AIS) classification A-D (n = 15). Pressure offloading was measured in individuals with SCI and correlated with tissue health measurements. Results: The area overlying the IT occupied by the muscle was significantly greater in the SCI when compared with AB cohort. The area occupied by the muscle in individuals with SCI appeared to lose the striated appearance and was more echogenic than nearby skin and subcutaneous tissue (ST). There was no correlation between offloading times and thickness, echogenicity and contrast measurements of skin, ST and muscle in individuals with SCI. Conclusion: Changes in soft tissues overlying the ischial tuberosity occur following SCI corresponding to the loss of striated appearance of muscle and increased thickness of the area occupied by the muscle. Further studies using a larger sample size are recommended to establish if thickness and tissue texture differ between individuals with SCI who sustain pressure injuries vs. those who do not.

The tissue viability imaging system-Suitable method for discovering minimal skin changes in occupational screenings? Results of a cross-sectional field study

BACKGROUND

For early detection of initial skin changes in occupational screenings, only few objective assessment systems are available.

OBJECTIVES

With the aim of assessing an objective measurement method for hand eczema, we trialed the application of the tissue viability imaging (TiVi) system, quantifying erythema non-invasively by polarized light spectroscopy.

MATERIALS AND METHODS

In a field study with 625 employees of a semiconductor production company, 411 were exposed to prolonged wearing of occlusive gloves in the clean room. TiVi system and Hand Eczema Score for Occupational Screenings (HEROS), a quantitative skin score for the hands, were used, supplemented by a standardized personal interview.

RESULTS

TiVi values of 65 up to 246 for each hand (palm or back), for each participant summed to overall 289 up to 848 (median 389), were measured. Higher TiVi values were noted for men, smokers, and with increasing age. Correlation between TiVi and HEROS was only weak. Several factors like skin pigmentation, thickness of the skin, or tattoos seem to influence TiVi results.

CONCLUSIONS

The practical relevance of one-time measurements with the TiVi system in occupational screenings seems to be limited. Specifically, the TiVi system cannot replace dermatological examinations at the workplace. Notwithstanding, the application for other scientific purposes might be useful.

An integrative review of skin assessment tools used to evaluate skin injury related to external beam radiation therapy

AIMS AND OBJECTIVES

To review literature associated with external beam radiotherapy and skin damage. A focus of the literature search is to highlight and discuss the myriad of skin assessment tools that are available to the clinician when assessing skin injury in patients receiving external beam radiation therapy.

BACKGROUND

It is apparent that despite considerable work being progressed in the development of individualised skin assessment tools, uptake and use is poor. These tools are designed to assist the clinician in the evaluation of damaged skin and predict the radiation wound development pathway.

DESIGN

An integrated review can be used to address a mature or new and emerging topic through a systematic methodology, which is either theoretical or empirical, gained from research, practice or policy initiatives (Whittemore & Knafl, Journal of Advanced Nursing, 52, 2005, 546). This review is particularly concerned with the employment of skin assessment tools by clinicians in patients with radiation damaged skin. Using the search terms synonyms for radiation, skin and epidermal damage, PubMed/MEDLINE, Medical Complete and Web of Science databases were searched. Consulting professional peers was employed as part of the inclusion and exclusion process.

CONCLUSION

There is a high level of unpredictability about which patient will have an uncomplicated course of external beam radiotherapy. Variables may include, but are not limited to, an acute reaction, a delayed reaction resulting in actual skin damage or no visible skin disturbance. The skin assessment tools that are readily available are not regularly referenced in clinical practice when attempting to manage the many side effects of radiation therapy. Skin assessment tools require ongoing clinical validation, so they can be used to guide practitioners to undertake further assessment of skin integrity.

RELEVANCE TO CLINICAL PRACTICE

The current body of knowledge suggests clinicians caring for patients receiving therapeutic radiotherapy should consider integrating a recognised patient assessment skin framework into their daily routine. Such validated tools may add value to postradiotherapy patient care by providing a consistency of management and accordingly refining best practice.

Prick test: evolution towards automated reading

The prick test is one of the most common medical methods for diagnosing allergies, and it has been carried out in a similar and laborious manner over many decades. In an attempt to standardize the reading of the test, many researchers have tried to automate the process of measuring the allergic reactions found by developing systems and algorithms based on multiple technologies. This work reviews the techniques for automatic wheal measurement with the aim of pointing out their advantages and disadvantages and the progress in the field. Furthermore, it provides a classification scheme for the different technologies applied. The works discussed herein provide evidence that significant challenges still exist for the development of an automatic wheal measurement system that not only helps allergists in their medical practice but also allows for the standardization of the reading and data exchange. As such, the aim of the work was to serve as guideline for the development of a proper and feasible system.

Non-Invasive Detection of Anaemia Using Digital Photographs of the Conjunctiva

BACKGROUND AND AIMS

Anaemia is a major health burden worldwide. Although the finding of conjunctival pallor on clinical examination is associated with anaemia, inter-observer variability is high, and definitive diagnosis of anaemia requires a blood sample. We aimed to detect anaemia by quantifying conjunctival pallor using digital photographs taken with a consumer camera and a popular smartphone. Our goal was to develop a non-invasive screening test for anaemia.

PATIENTS AND METHODS

The conjunctivae of haemato-oncology in- and outpatients were photographed in ambient lighting using a digital camera (Panasonic DMC-LX5), and the internal rear-facing camera of a smartphone (Apple iPhone 5S) alongside an in-frame calibration card. Following image calibration, conjunctival erythema index (EI) was calculated and correlated with laboratory-measured haemoglobin concentration. Three clinicians independently evaluated each image for conjunctival pallor.

RESULTS

Conjunctival EI was reproducible between images (average coefficient of variation 2.96%). EI of the palpebral conjunctiva correlated more strongly with haemoglobin concentration than that of the forniceal conjunctiva. Using the compact camera, palpebral conjunctival EI had a sensitivity of 93% and 57% and specificity of 78% and 83% for detection of anaemia (haemoglobin < 110 g/L) in training and internal validation sets, respectively. Similar results were found using the iPhone camera, though the EI cut-off value differed. Conjunctival EI analysis compared favourably with clinician assessment, with a higher positive likelihood ratio for prediction of anaemia.

CONCLUSIONS

Erythema index of the palpebral conjunctiva calculated from images taken with a compact camera or mobile phone correlates with haemoglobin and compares favourably to clinician assessment for prediction of anaemia. If confirmed in further series, this technique may be useful for the non-invasive screening for anaemia.

Objective assessment in digital images of skin erythema caused by radiotherapy

PURPOSE

Skin toxicity caused by radiotherapy has been visually classified into discrete grades. The present study proposes an objective and continuous assessment method of skin erythema in digital images taken under arbitrary lighting conditions, which is the case for most clinical environments. The purpose of this paper is to show the feasibility of the proposed method.

METHODS

Clinical data were gathered from six patients who received carbon beam therapy for lung cancer. Skin condition was recorded using an ordinary compact digital camera under unfixed lighting conditions; a laser Doppler flowmeter was used to measure blood flow in the skin. The photos and measurements were taken at 3 h, 30, and 90 days after irradiation. Images were decomposed into hemoglobin and melanin colors using independent component analysis. Pixel values in hemoglobin color images were compared with skin dose and skin blood flow. The uncertainty of the practical photographic method was also studied in nonclinical experiments.

RESULTS

The clinical data showed good linearity between skin dose, skin blood flow, and pixel value in the hemoglobin color images; their correlation coefficients were larger than 0.7. It was deduced from the nonclinical that the uncertainty due to the proposed method with photography was 15%; such an uncertainty was not critical for assessment of skin erythema in practical use.

CONCLUSIONS

Feasibility of the proposed method for assessment of skin erythema using digital images was demonstrated. The numerical relationship obtained helped to predict skin erythema by artificial processing of skin images. Although the proposed method using photographs taken under unfixed lighting conditions increased the uncertainty of skin information in the images, it was shown to be powerful for the assessment of skin conditions because of its flexibility and adaptability.

Evaluation of the clinical efficacy and safety of an eye counter pad containing caffeine and vitamin K in emulsified Emu oil base

BACKGROUND

People strive to maintain the best look and have a youthful appearance. The skin around the eye is an area without many oil glands and collagen in comparison to the body rest, so it is more prone to fine lines and dehydration, which makes it look dull. The aim of this research is to develop and evaluate in vivo efficacy of an anti-wrinkle and dark circle eye pad consisting of 3% w/w caffeine and 1% vitamin K in a convenient, healthy, and cosmeceutical base.

MATERIALS AND METHODS

Pre-emulsions containing selected ingredients in a specified effective concentration were prepared. The selected formulation, based upon pharmaceutical parameters, was coated on a nonwoven fabric in an eye counter shape, and stored in a jar. Then in vivo trial was carried out for investigation of its anti-wrinkling efficacy on 11 healthy women. In a single blind trial, the sample pad was applied under the right eye and the placebo pad, consisting of water, was placed under the left eye simultaneously. The efficacy and safety of the formulation was evaluated visually and with a multi skin test MC 900 instrument.

RESULT

After four weeks, the skin around the right eye of all the subjects experienced a reduction in the depth of wrinkles and dark circles, and from a subjective point of view, the appearance and elasticity of the skin were improved.

CONCLUSIONS

The caffeine pad containing vitamin K in an Emu oil base shows an improvement in eye counter appearance with anti-dark circle capacity and as an emollient.

Digital imaging analysis to assess scar phenotype

In order to understand the link between the genetic background of patients and wound clinical outcomes, it is critical to have a reliable method to assess the phenotypic characteristics of healed wounds. In this study, we present a novel imaging method that provides reproducible, sensitive, and unbiased assessments of postsurgical scarring. We used this approach to investigate the possibility that genetic variants in orofacial clefting genes are associated with suboptimal healing. Red-green-blue digital images of postsurgical scars of 68 patients, following unilateral cleft lip repair, were captured using the 3dMD imaging system. Morphometric and colorimetric data of repaired regions of the philtrum and upper lip were acquired using ImageJ software, and the unaffected contralateral regions were used as patient-specific controls. Repeatability of the method was high with intraclass correlation coefficient score > 0.8. This method detected a very significant difference in all three colors, and for all patients, between the scarred and the contralateral unaffected philtrum (p ranging from 1.20(-05) to 1.95(-14) ). Physicians' clinical outcome ratings from the same images showed high interobserver variability (overall Pearson coefficient = 0.49) as well as low correlation with digital image analysis results. Finally, we identified genetic variants in TGFB3 and ARHGAP29 associated with suboptimal healing outcome.

Objectifying the conjunctival provocation test: photography-based rating and digital analysis

BACKGROUND

Patients with allergic rhinoconjunctivitis are susceptible to both nasal and ocular symptoms. The conjunctival provocation test (CPT) is an established diagnostic procedure used in allergic rhinoconjunctivitis, particularly to document a patient's current reactivity to allergens. To date, there are no international guidelines defining the CPT. No approved evaluation method exists for interpreting CPT results. This paper aims to establish the digital analysis of macroimages as an objective, validated and standardized method for interpreting CPT results.

METHODS

In a clinical immunotherapy trial with 155 patients, treatment progress was documented based on the CPT. Local investigators used a symptom score to grade tearing, reddening and the patients' subjective perception of symptoms (mucosal irritation). A central observer rated conjunctival hyperemia via digital photography. Digital image analysis software was utilized to determine conjunctival hyperemia.

RESULTS

Spearman's correlation between the local investigators' and the central observer's ratings was r = 0.729 (p < 0.001); the percentage of total agreement was 48% (based on 739 photos). Digital image analysis (based on 48 photos) had a high percentage of total agreement with the central observer's ratings (69%) but a low percentage of total agreement with the investigators' ratings (38%). The corresponding correlations were r = 0.264 and 0.064, respectively.

CONCLUSION

Photography-based rating by a central observer may represent a valuable supplement to the local investigator's assessment for making an objective evaluation of CPT results. Digital image analysis possesses the potential of being an objective evaluation method compared to the wide-spread subjective evaluation by the investigators.

Update on techniques for the quantitation of facial skin characteristics

The purpose of this article is to review the strategies and methods for quantifying treatment outcomes, perhaps defined by the consumer/patient as a "decrease in perceived age." The demand for the rejuvenation of facial skin is expected to increase as the population ages and seeks optimal outcomes from the array of available treatment modalities. This information will be of value to the plastic surgeon in collaborating with patients on evaluation and treatment strategies.

Quantitative evaluation of efficacy of photodynamic therapy for port-wine stains using erythema index image analysis

BACKGROUND

Methods for quantitatively evaluate the efficacy of photodynamic therapy (PDT) for port-wine stains (PWS) are still needed for clinical practice and studies.

METHODS

50 pairs of pictures before and after PDT of 40 PWS patients were selected. Each PWS lesion was labeled with a marker of red color graded 0-9. These pictures were taken without assistance of instruments to keep same position or distance and were referred to as 'experimental' images. 70 labels were photographed at a fixed position and distance with the assistance of a bracket and the images obtained were referred to as 'standardized' ones. An independent group of three experts viewed the photos and assessed the efficacy. The images were processed and measured for erythema index (EI) with the ImageJ freeware. The EI difference (ΔEI) and the percent change of ΔEI ((ratio)ΔEI(%)) of the labels and the PWS lesions was computed separately.

RESULTS

Significant differences of EI, ΔEI and (ratio)ΔEI(%) were found between each two grades of the color markers in both standardized and experimental images. ΔEI of lesions achieved 'almost cured' and 'great improvement' after PDT was significantly reduced than before PDT. Significantly greater percentages of lesions were assessed as 'response' and 'significant response' in those of (before)ΔEI≥35 compared to those of (before)ΔEI<35. The (ratio)ΔEI(%) decrease of lesions assessed as 'almost cured', 'great improvement' and 'some improvement' was significantly reduced sequentially.

CONCLUSION

The EI image analysis is a valid method for quantitatively evaluating efficacy of PDT for PWS.

Quantifying the aesthetic outcomes of breast cancer treatment: assessment of surgical scars from clinical photographs

RATIONALE

Accurate assessment of the degree of scaring that results from surgical intervention for breast cancer would enable more effective pre-operative counselling. The resultant scar that accompanies an open surgical intervention may be characterized by variance in thickness, colour and contour. These factors significantly impact the overall appearance of the breast. A number of studies have addressed the mechanical and pathologic aspects of scarring. The majority of these investigations have focused on the physiologic process of scar formation and means to improve the qualities of a scar. Few studies have focused on quantifying the visual impact of scars.

METHODS

This manuscript critically reviews current methods used to assess scars in terms of overall satisfaction after surgery. We introduce objective, quantitative measures for assessing linear breast surgical scars using digital photography. These new measurements of breast surgical scars are based on calculations of contrast and area.

RESULTS AND CONCLUSIONS

We demonstrate, using the intra-class correlation coefficient, that the new measures are robust to observer variability in annotating the scar region on clinical photographs. As an example of the utility of the new measures, we use them to quantify the aesthetic differences of reconstruction following skin-sparing mastectomy vs. conventional mastectomy.

Significant differences in skin irritation by common suture materials assessed by a comparative computerized objective method

BACKGROUND

Erythema can be described only through subjective evaluation, except when it is quantified by digital image analysis software. Using such software, the authors performed comparisons of the erythema produced after skin closure of clean surgical wounds. Five suture materials were compared with respect to the local skin irritation that was caused. Different quantities of erythema are produced by suture material after the skin closure of clean surgical wounds. The authors present an objective method of measuring how unreactive a suture material is in comparison with another when applied to the skin.

METHODS

The suture materials polydioxanone, polypropylene blue, polyamide 6, metallic clips, and polyglactin were compared in the present study. Digital photographs of 100 patients were compared by means of software, evaluating red color superiority (mean value of red color) in the region surrounding the wound.

RESULTS

The least to most irritation caused to the skin by different suture materials was established for paired data. The Kolmogorov-Smirnov criterion and the Wilcoxon signed rank test were used. Polydioxanone was found to have the best performance, followed in order by polyglactin, polyamide, polypropylene, and metallic clips. Immediately after suture removal, differences between the effects of suture materials were statistically significant on postoperative day 10.

CONCLUSIONS

Absorbable sutures can be used in skin closure of clean surgical wounds and can produce less erythematous reaction than nonabsorbable ones. Digital image analysis is a reliable method of quantitative evaluation of skin erythema resulting after skin closure of surgical wounds.

Quantitation of epidermal and mucosal tissue injury using contrast agents and imaging techniques

BACKGROUND/PURPOSE

Epidermal injury is common but the accuracy of visual methods is significantly impacted by the inherent skin pigmentation. We examined imaging and fluorescence techniques to quantify tissue injury as a function of skin color.

METHODS

Epidermal and mucosal scratches were created in 20 light- (L(*) 68.2+/-2.3) and 20 dark-skinned (L(*) 46.4+/-5.2) females. Injured and uninjured sites were treated with toluidine blue (TB), fluorescein (FL) and a TB/FL mixture and photographed under conditions of white and fluorescent light. Area and intensity parameters were determined.

RESULTS

Injured sites with TB and TB/FL had higher areas than the control for both light and dark subjects (ANOVA, P<0.05). The intensity of the injured TB site was higher than the control for light skin only. The areas of injured sites with FL and TB/FL were higher than the control for both groups as were the intensities of the injured sites with FL. The findings were similar for the lip skin.

CONCLUSIONS

Application of TB and FL contrasts under white and fluorescent light can be used to quantify tissue injuries for L(*) values >35 and is a promising approach for the quantitation across a range of skin pigmentation.

Use of digital photography and image analysis techniques to quantify erythema in health care workers

BACKGROUND/AIMS

Nosocomial infections affect up to 26% of ICU patients. Compliance with the required hand hygiene procedures remains low, rarely exceeding 50%, with skin irritation as one of the main reasons for lack of conformity. The aim was to quantify the epidermal barrier effects, particularly erythema, from repetitive exposure to hand hygiene procedures among health care workers (HCWs) using an objective, reliable clinical method that could evaluate the entire hand surface.

METHODS

The hand skin of HCWs was evaluated before the initial scrub and at the end of multiple 2-3 days work cycles during spring (n=54) and winter (n=60) trials. The skin condition was measured with live visual skin evaluation (LSG), digital image analysis (DIA) of high-resolution digital images, and visual perception evaluation (VPS) of image pairs.

RESULTS

The HCWs had significantly higher values of erythema than the non-HCW control group with all methods. Knuckle erythema increased over the cycle in both seasons. It decreased during recovery in spring and continued to increase during recovery in winter. For the DIA area of excess redness, the quantitative measure of erythema, the decrease over the cycle in spring was significantly different than the increase over the cycle in winter. Minimal changes in area of excess redness occurred during recovery in both seasons. With the VPS, both judges found a decrease in erythema during recovery in spring and an increase during recovery in winter, indicating significant differences for spring vs. winter (P<0.05). No differences in VPS erythema were seen for either product set over the work cycle during spring. Correlations were observed for (1) results for the VPS vs. the LSG method and (2) between excess erythema (mu+sigma) from DIA and the VPS erythema scores. Relatively low correlations were found between the DIA and VPS methods, i.e., knuckle mu+sigma and VPS erythema.

CONCLUSIONS

Significant work cycle effects for spring vs. winter were observed with DIA, while significant effects were found during the recovery period with VPS. DIA produced an objective quantitative measure of erythema that was not limited or influenced by other aspects of skin irritation (e.g., dryness, scaling) or texture encountered in the visual methods of LSG and VPS. The DIA method minimizes the difficulty in differentiating erythema severity. Standardization of image capture and processing allows assessment of skin condition across clinical locations. The VPS is a more reliable way to compare skin condition at different times, i.e. beginning vs. the end of a treatment cycle, because images are viewed simultaneously and can be carefully examined for differences.

Multimodal facial color imaging modality for objective analysis of skin lesions

We introduce a multimodal facial color imaging modality that provides a conventional color image, parallel and cross-polarization color images, and a fluorescent color image. We characterize the imaging modality and describe the image analysis methods for objective evaluation of skin lesions. The parallel and cross-polarization color images are useful for the analysis of skin texture, pigmentation, and vascularity. The polarization image, which is derived from parallel and cross-polarization color images, provides morphological information of superficial skin lesions. The fluorescent color image is useful for the evaluation of skin chromophores excited by UV-A radiation. In order to demonstrate the validity of the new imaging modality in dermatology, sample images were obtained from subjects with various skin disorders and image analysis methods were applied for objective evaluation of those lesions. In conclusion, we are confident that the imaging modality and analysis methods should be useful tools to simultaneously evaluate various skin lesions in dermatology.

Objective evaluation of skin prick test reactions using digital photography

BACKGROUND

The skin prick test has been used worldwide to determine IgE-mediated hypersensitivity. However, the most current method to record this reaction has problems with accuracy and precision.

OBJECTIVE

To demonstrate a new approach to measure the skin prick reaction and its kinetics with precision.

METHODS

The skin prick test was induced using histamine or Dermatophagoides pteronyssinus antigen in 80 volunteers aged 4 and 67 years who had different skin colors. Digital photographs were obtained at 0, 3, 5, 10, 15 and 20 min. The mean wheal and erythema area as well as the erythema intensity were determined using Adobe Photoshop software. The accuracy and precision of this approach were also evaluated.

RESULTS

The digital photographic analysis measured the wheal and erythema sizes independent of the antigen or skin color with precision. In addition, a new variable of this test, the skin erythema intensity, could be determined objectively using the chromaticity of reflected light.

CONCLUSIONS

Digital photographic analysis is a precise and objective method to evaluate the skin prick test reaction, which can be used independent of the patient's skin color in clinical or research settings.

Effects of Topical Copper Tripeptide Complex on CO2 Laser–Resurfaced Skin

OBJECTIVE

To evaluate the role of skin care products that contain a copper tripeptide complex, glycyl-l-histidyl-l-lysine-Cu(2+) (GHK-Cu), in treating carbon dioxide (CO(2)) laser-resurfaced skin.

METHODS

Patients meeting the inclusion criteria underwent circumoral skin resurfacing using a CO(2) laser at standard settings. Patients were then randomized to receive posttreatment skin regimens with or without GHK-Cu. Evaluations for erythema throughout the posttreatment period were performed using computer software and blinded evaluators. In addition, overall improvement in wrinkles and overall improvement in skin appearance 12 weeks after treatment were assessed. Patients completed a validated questionnaire before and 12 weeks after treatment.

RESULTS

Thirteen patients completed the study. Computer analysis and blinded evaluators found no statistically significant differences between groups for earlier resolution of erythema. All the patients experienced significant improvement in wrinkles and overall skin quality, but no differences were found between groups. The results of the questionnaire indicated a significant difference in the posttreatment improvement of overall skin quality for patients using GHK-Cu (P = .04).

CONCLUSIONS

Copper tripeptide complex (GHK-Cu) skin care products placed on CO(2) laser-resurfaced skin offered no significant reduction or resolution of posttreatment erythema. Objective evaluation found no significant improvement in wrinkles or overall skin quality. However, patient satisfaction was significantly higher for those who used GHK-Cu skin care products after CO(2) laser skin resurfacing.

Use of erythema index imaging for systematic analysis of port wine stain skin response to laser therapy

BACKGROUND AND OBJECTIVES

Quantitative methods to assess port wine stain (PWS) skin response to laser therapy are needed to improve therapeutic outcome. In this study, PWS skin erythema was analyzed using erythema index difference (DeltaEI: erythema index difference between PWS and normal skin) images before and after treatment to investigate systematically subject-dependent response to laser therapy.

STUDY DESIGN/MATERIALS AND METHODS

Cross-polarized digital skin color images were acquired from 17 subjects with facial PWS and the associated DeltaEI images were computed. Qualitative and quantitative analyses of PWS skin erythema were performed with DeltaEI images, in which ranges of 40-6 and 5-0 represented PWS and normal skin, respectively.

RESULTS

After laser therapy, we qualitatively observed a reduction in the DeltaEI values for all subjects. Regression fitting of DeltaEI values before and after PWS laser therapy was associated with strong positive linear correlation.

CONCLUSIONS

The imaging modality and analysis method allowed systematic analysis of PWS skin erythema in response to laser therapy. PWS skin response was dependent on pretreatment DeltaEI values, suggesting that erythema can be utilized as an effective parameter to monitor PWS response to laser therapy.

Practical color calibration for dermoscopy, applied to a digital epiluminescence microscope

BACKGROUND/PURPOSE

The assessment of colors is essential for melanoma (MM) diagnosis, both for pattern analysis on dermoscopic images, and when using semiquantitative methods. Our aim was to provide a simple, precise characterization and reproducible calibration of the color response for dermoscopic instruments.

METHODS

Three processes were used to correct the non-uniform illumination pattern of the instrument, to easily estimate the camera gamma settings and to describe the color space conversion matrices required to produce standard images, in any color space. A specific color space was also developed to optimize the representation of dermatoscopic colors. The calibration technique was tested both on synthetic reference surfaces and on real images by comparing the difference between the images colors obtained with two different equipments.

RESULTS

The differences between the images acquired by means of the two instruments, calculated on the reference patterns after calibration, were up to 10 times lower then before, while comparison of histograms referring to real images provided an improvement of about seven times on average.

CONCLUSIONS

A complete workflow for dermatologic image calibration, which allows the user to continue using his own software and algorithms, but with a much higher informative content, is presented. The technique is simple and may improve cooperation between different research centers, in teleconsulting contexts or for result comparisons.

Determination of optimal view angles for quantitative facial image analysis

In quantitative evaluation of facial skin chromophore content using color imaging, several factors such as view angle and facial curvature affect the accuracy of measured values. To determine the influence of view angle and facial curvature on the accuracy of quantitative image analysis, we acquire cross-polarized diffuse reflectance color images of a white-patched mannequin head model and human subjects while varying the angular position of the head with respect to the image acquisition system. With the mannequin head model, the coefficient of variance (CV) is determined to specify an optimal view angle resulting in a relatively uniform light distribution on the region of interest (ROI). Our results indicate that view angle and facial curvature influence the accuracy of the recorded color information and quantitative image analysis. Moreover, there exists an optimal view angle that minimizes the artifacts in color determination resulting from facial curvature. In a specific ROI, the CV is less in smaller regions than in larger regions, and in relatively flat regions. In clinical application, our results suggest that view angle affects the quantitative assessment of port wine stain (PWS) skin erythema, emphasizing the importance of using the optimal view angle to minimize artifacts caused by nonuniform light distribution on the ROI. From these results, we propose that optimal view angles can be identified using the mannequin head model to image specific regions of interest on the face of human subjects.

Characterization of port wine stain skin erythema and melanin content using cross-polarized diffuse reflectance imaging

BACKGROUND AND OBJECTIVES

Objective methods to assess quantitatively port wine stain (PWS) blanching in response to laser therapy are needed to improve laser therapeutic outcome. Previous studies have attempted to assess objectively PWS color based on point measurement devices. To date, these approaches have typically been limited by a number of factors such as small test area and need for contact. To address these issues, a cross-polarized diffuse reflectance imaging system and color image analysis method has been developed to evaluate quantitatively erythema and melanin content in PWS skin.

STUDY DESIGN/MATERIALS AND METHODS

A cross-polarized diffuse reflectance system has been constructed to acquire high resolution digital images while minimizing artifacts such as glare, shadowing, and nonuniform illumination effects that can compromise image fidelity. Furthermore, an image analysis algorithm has also been developed to analyze normal and PWS skin in terms of CIEL*a*b* color space parameters. Using the algorithm, images of color space intensity, L*, and saturation, a*, indices have been calculated to extract quantitative metrics of melanin and erythema, respectively.

RESULTS

Compared to the cross-polarized diffuse reflectance image, the a* index image enhanced the contrast in regions of high and low erythema and seems to have quasi correlation with the L* index image. In the presented PWS patient example, the relative a* index difference (Deltaa*) image showed less erythema in PWS skin after laser treatment when compared to pre-treatment values.

CONCLUSIONS

Our cross-polarized imaging system and color image analysis method is a simple, noncontact technique that can indirectly provide quantitative measurement of erythema and melanin content in PWS skin.