Influence of Ambient Stressors and Time Constraints on Diagnostic Accuracy of Borderline Pigmented Skin Lesions.

BACKGROUND: Health professionals are required to make complex decisions in dynamic contexts involving many variables and factors. Decisions are more difficult in the presence of uncertainty, urgency and high risk. OBJECTIVE: To evaluate the effect of ambient stressors and time constraints on decision making by expert dermatologists faced with borderline pigmented skin lesions (PSL) (early melanoma vs. atypical nevi). METHODS: We performed a retrospective chart review of PSL from the image databases of our department. A total of 321 PSL (219 nevi and 102 melanomas) were randomly assigned to three groups: control group, ambient stress group and time stress group. The diagnostic accuracy of each group was evaluated as sensitivity and specificity. RESULTS: Mean sensitivity and specificity of diagnosis were 69.2 and 90.5% in the control group, 62 and 81.2% in the ambient stress group and 59.6 and 82.5% in the time stress group, respectively. CONCLUSION: Time constraints and stressors negatively influenced the performance of dermatologists in the diagnosis of atypical PSL.

Melanoma computer-aided diagnosis: reliability and feasibility study.

BACKGROUND: Differential diagnosis of melanoma from melanocytic nevi is often not straightforward. Thus, a growing interest has developed in the last decade in the automated analysis of digitized images obtained by epiluminescence microscopy techniques to assist clinicians in differentiating early melanoma from benign skin lesions. PURPOSE: The aim of this study was to evaluate diagnostic accuracy provided by different statistical classifiers on a large set of pigmented skin lesions grabbed by four digital analyzers located in two different dermatological units. EXPERIMENTAL DESIGN: Images of 391 melanomas and 449 melanocytic nevi were included in the study. A linear classifier was built by using the method of receiver operating characteristic curves to identify a threshold value for a fixed sensitivity of 95%. A K-nearest-neighbor classifier, a nonparametric method of pattern recognition, was constructed using all available image features and trained for a sensitivity of 98% on a large exemplar set of lesions. RESULTS: On independent test sets of lesions, the linear classifier and the K-nearest-neighbor classifier produced a mean sensitivity of 95% and 98% and a mean specificity of 78% and of 79%, respectively. CONCLUSIONS: In conclusion, our study suggests that computer-aided differentiation of melanoma from benign pigmented lesions obtained with DB-Mips is feasible and, above all, reliable. In fact, the same instrumentations used in different units provided similar diagnostic accuracy. Whether this would improve early diagnosis of melanoma and/or reducing unnecessary surgery needs to be demonstrated by a randomized clinical trial.

Digital dermoscopy analysis and artificial neural network for the differentiation of clinically atypical pigmented skin lesions: a retrospective study.

Noninvasive diagnostic methods such as dermoscopy or epiluminescence light microscopy have been developed in an attempt to improve diagnostic accuracy of pigmented skin lesions. The evaluation of the many morphologic characteristics of pigmented skin lesions observable by epiluminescence light microscopy, however, is often extremely complex and subjective. With the aim of obviating these problems of qualitative interpretation, methods based on mathematical analysis of pigmented skin lesions have recently been designed. These methods are based on computerized analysis of digital images obtained by epiluminescence light microscopy. In this study we used a digital dermoscopy analyzer with 147 clinically atypical pigmented skin lesions (90 nevi and 57 melanomas) to determine its discriminating power with respect to histologic diagnosis. The system evaluated 48 objective parameters used to train an artificial neural network. Using the artificial neural network with 10 variables selected by a stepwise procedure, we obtained a maximum accuracy in distinguishing melanoma from benign lesions of about 93%. Comparing this result with those of the many studies using classical epiluminescence light microscopy, it emerges that the method proposed is equal or even superior in diagnostic accuracy and has the advantage of not depending on the expertise of the clinician who examines the lesion.

Dermoscopic patterns of cutaneous melanoma metastases.

In 2-8% of patients with melanoma, the first clinical manifestation of the disease may be skin metastasis. In these cases, differential diagnosis with the primary melanoma, benign melanocytic lesions, and other malignant and benign skin growths is particularly challenging. For this reason, the dermatologist's approach to cutaneous metastases of malignant melanoma calls for knowledge of the great morphological variety of these lesions. Dermoscopic characteristics associated with CMMMs have not yet been codified. The aim of the present review is to provide additional information about dermoscopic aspects of these skin lesions.

Reflectance imaging of the human retina at 810 nm does not suffice to optimize the parameters of hydrodynamic rebalancing laser treatment.

The hydrodynamic rebalancing laser (HRL) procedure is an ophthalmic therapy based on the administration of subthreshold infrared (810 nm) laser light to selected areas on the retina to treat various retina diseases. Heterogeneities of tissue response are observed, including undesired retinal damages. Variations of tissue absorbance were hypothesized to cause this uneven response. Irradiation parameters (diameter = 100 µm; power = 1 W; irradiation time: 50 to 200 ms), location and tissue response were studied in 16 patients (20 eyes, 2535 laser spots) to discover any correlation between tissue response and normalized fundus reflectance at 810 nm. The results demonstrate a complex relationship between some pathologies and occurrences of retinal damage, but no clear correlation. One possible reason is that the resolution of reflectance images is insufficient to see "small" (40 µm or less) absorption centers, particularly deep-seated ones. Additionally, tissue parameters other than variations of the fundus optical absorption influence heat diffusion and temperature increases. Monitoring or individualizing the light dose in HRL therapy, or any similar infrared diode laser-based therapy will require more sophisticated technologies, including imaging the retina's reflectance with an improved resolution, as well as refined methods to detect complex correlations between retinal damage and specific pathologies.

Objective follow-up of atypical melanocytic skin lesions: a retrospective study.

Various authors have suggested that information from longitudinal observation (follow-up) of dynamic changes in atypical melanocytic pigmented skin lesions (MPSL) could enable identification of early malignant melanoma escaping initial observation due to an absence of specific clinical and dermoscopic features. The aim of our retrospective study was to determine the existence of numerical variables regarding changes in MPSL that could be useful to differentiate early melanomas and atypical nevi. The study was carried out in two Italian dermatology Centres. Digital dermoscopy analyzers (DB-Mips System) were used to evaluate dermoscopic images of 94 equivocal pigmented skin lesions under observation for 6-12 months and then excised because of changes across time (29 melanomas and 65 nevi). The analyzer evaluates 49 parameters grouped into four categories: geometries, colours, textures and islands of colour. The ROC curve designed on the 49 digital dermoscopy analysis parameters showed good accuracy. At sensitivity (SE) = specificity (SP), it correctly classified 89.3% of cases. When objective pigmented skin lesion parameters were considered together with their objective changes over 6-12 months, a decisive increase in discrimination capacity was obtained. At SE = SP accuracy was 96.3%. Analysis of the parameters of our model and statistical analysis enabled us to interpret/identify the most significant factors of modification and differentiation of lesions, providing quantitative insights into the diagnosis of equivocal MPSL and demonstrating the utility of objective/numerical follow-up.

Dimensional contour stability of acrylic resin bases for complete dentures before and after water sorption.

PURPOSE: To evaluate the dimensional contour variations of acrylic resin denture bases before and after storage in water. MATERIALS AND METHODS: The fit of 40 bases was evaluated by measuring the thickness of a layer made with silicone placed between the bases and the casts. The measurements were repeated on a new set of silicone layers after having stored the bases in water for 42 days. RESULTS: Significant differences were found both for the maxillary and the mandibular bases. CONCLUSION: Water sorption had an important effect on the contour of the prosthetic bases.

Skin allograft in the treatment of toxic epidermal necrolysis (TEN).

BACKGROUND: TEN is a severe form of exfoliative dermatitis. Its course is acute and its outcome fatal in 40% of cases. Wound cover to prevent fluid/protein loss and infections and to control pain, is the first step, as for burns. Skin allograft can be successfully used for this purpose. OBJECTIVE: We report two cases of TEN with de-epithelialization of 50 and 70% of the total body surface area. The patients were given support therapy and treated with human glycerol-preserved skin allografts for wound cover. METHODS: Patients were grafted with glycerol-preserved donor skin, obtained from a skin bank. RESULTS: Re-epithelization of treated areas was complete in 8 days; pain relief was obtained soon after the graft. CONCLUSIONS: Glycerol-preserved skin allograft is an effective treatment in extensive skin loss, for its barrier and analgesic effect. Quality standards of this product ensure safety and simplicity of use at limited cost.

Automated diagnosis of pigmented skin lesions.

Since advanced melanoma remains practically incurable, early detection is an important step toward a reduction in mortality. High expectations are entertained for a technique known as dermoscopy or epiluminescence light microscopy; however, evaluation of pigmented skin lesions by this method is often extremely complex and subjective. To obviate the problem of qualitative interpretation, methods based on mathematical analysis of pigmented skin lesions, such as digital dermoscopy analysis, have been developed. In the present study, we used a digital dermoscopy analyzer (DBDermo-Mips system) to evaluate a series of 588 excised, clinically atypical, flat pigmented skin lesions (371 benign, 217 malignant). The analyzer evaluated 48 parameters grouped into 4 categories (geometries, colors, textures and islands of color), which were used to train an artificial neural network. To evaluate the diagnostic performance of the neural network and to check it during the training process, we used the error area over the receiver operating characteristic curve. The discriminating power of the digital dermoscopy analyzer plus artificial neural network was compared with histologic diagnosis. A feature selection procedure indicated that as few as 13 of the variables were sufficient to discriminate the 2 groups of lesions, and this also ensured high generalization power. The artificial neural network designed with these variables enabled a diagnostic accuracy of about 94%. In conclusion, the good diagnostic performance and high speed in reading and analyzing lesions (real time) of our method constitute an important step in the direction of automated diagnosis of pigmented skin lesions.

Dermoscopy of pigmented skin lesions: results of a consensus meeting via the Internet.

BACKGROUND: There is a need for better standardization of the dermoscopic terminology in assessing pigmented skin lesions. OBJECTIVE: The virtual Consensus Net Meeting on Dermoscopy was organized to investigate reproducibility and validity of the various features and diagnostic algorithms. METHODS: Dermoscopic images of 108 lesions were evaluated via the Internet by 40 experienced dermoscopists using a 2-step diagnostic procedure. The first-step algorithm distinguished melanocytic versus nonmelanocytic lesions. The second step in the diagnostic procedure used 4 algorithms (pattern analysis, ABCD rule, Menzies method, and 7-point checklist) to distinguish melanoma versus benign melanocytic lesions. kappa Values, log odds ratios, sensitivity, specificity, and positive likelihood ratios were estimated for all diagnostic algorithms and dermoscopic features. RESULTS: Interobserver agreement was fair to good for all diagnostic methods, but it was poor for the majority of dermoscopic criteria. Intraobserver agreement was good to excellent for all algorithms and features considered. Pattern analysis allowed the best diagnostic performance (positive likelihood ratio: 5.1), whereas alternative algorithms revealed comparable sensitivity but less specificity. Interobserver agreement on management decisions made by dermoscopy was fairly good (mean kappa value: 0.53). CONCLUSION: The virtual Consensus Net Meeting on Dermoscopy represents a valid tool for better standardization of the dermoscopic terminology and, moreover, opens up a new territory for diagnosing and managing pigmented skin lesions.