We report on the fabrication of spherical Au spheres by pulsed laser treatment using a KrF excimer laser (248 nm, 25 ns) under ambient conditions as a fast and high throughput fabrication technique. ...The presented experiments were realized using initial Au layers of 100 nm thickness deposited on optically transparent and low cost Borofloat glass or single-crystalline SrTiO
substrates, respectively. High (111)-orientation and smoothness (RMS ≈ 1 nm) are the properties of the deposited Au layers before laser treatment. After laser treatment, spheres with size distribution ranging from hundreds of nanometers up to several micrometers were produced. Single-particle scattering spectra with distinct plasmonic resonance peaks are presented to reveal the critical role of optimal irradiation parameters in the process of laser induced particle self-assembly. The variation of irradiation parameters like fluence and number of laser pulses influences the melting, dewetting and solidification process of the Au layers and thus the formation of extremely well shaped spherical particles. The gold layers on Borofloat glass and SrTiO
are found to show a slightly different behavior under laser treatment. We also discuss the effect of substrates.
IMPORTANCE: Convolutional neural networks (CNNs) achieve expert-level accuracy in the diagnosis of pigmented melanocytic lesions. However, the most common types of skin cancer are nonpigmented and ...nonmelanocytic, and are more difficult to diagnose. OBJECTIVE: To compare the accuracy of a CNN-based classifier with that of physicians with different levels of experience. DESIGN, SETTING, AND PARTICIPANTS: A CNN-based classification model was trained on 7895 dermoscopic and 5829 close-up images of lesions excised at a primary skin cancer clinic between January 1, 2008, and July 13, 2017, for a combined evaluation of both imaging methods. The combined CNN (cCNN) was tested on a set of 2072 unknown cases and compared with results from 95 human raters who were medical personnel, including 62 board-certified dermatologists, with different experience in dermoscopy. MAIN OUTCOMES AND MEASURES: The proportions of correct specific diagnoses and the accuracy to differentiate between benign and malignant lesions measured as an area under the receiver operating characteristic curve served as main outcome measures. RESULTS: Among 95 human raters (51.6% female; mean age, 43.4 years; 95% CI, 41.0-45.7 years), the participants were divided into 3 groups (according to years of experience with dermoscopy): beginner raters (<3 years), intermediate raters (3-10 years), or expert raters (>10 years). The area under the receiver operating characteristic curve of the trained cCNN was higher than human ratings (0.742; 95% CI, 0.729-0.755 vs 0.695; 95% CI, 0.676-0.713; P < .001). The specificity was fixed at the mean level of human raters (51.3%), and therefore the sensitivity of the cCNN (80.5%; 95% CI, 79.0%-82.1%) was higher than that of human raters (77.6%; 95% CI, 74.7%-80.5%). The cCNN achieved a higher percentage of correct specific diagnoses compared with human raters (37.6%; 95% CI, 36.6%-38.4% vs 33.5%; 95% CI, 31.5%-35.6%; P = .001) but not compared with experts (37.3%; 95% CI, 35.7%-38.8% vs 40.0%; 95% CI, 37.0%-43.0%; P = .18). CONCLUSIONS AND RELEVANCE: Neural networks are able to classify dermoscopic and close-up images of nonpigmented lesions as accurately as human experts in an experimental setting.
Most studies on dermoscopy of acral lesions were conducted in Asian populations. In this study, we analyzed these features in a predominantly Caucasian population.
Estimate the prevalence of ...dermoscopic features in acral lesions, and assess their level of agreement between observers.
In this retrospective multicenter study, 167 acral lesions (66 melanomas) were evaluated for 13 dermoscopic patterns by 26 physicians, via a secured Internet platform.
Parallel furrow pattern, bizarre pattern, and diffuse pigmentation with variable shades of brown had the highest prevalence. The agreement for lesion patterns between physicians was variable. Agreement was dependent on the level of diagnostic difficulty.
Lesions with a diameter >1 cm were more likely to be melanoma. We found as well that a benign pattern can be seen in parts of melanomas. For this reason one should evaluate an acral lesion for the presence of malignant patterns first.
Summary
Background Dermoscopic vascular criteria remain poorly evaluated and analysed. The increasing number of descriptions of amelanotic melanoma showing isolated vascular dermoscopic findings ...adds interest to this topic.
Objective To evaluate and classify the dermoscopic vascular structures seen in nontumoral dermatoses (NTD).
Patients and methods The affected skin of 414 consecutive patients suffering from a variety of 31 different biopsy‐proven NTD was evaluated with the dermoscope and photographed with the Dermaphot camera.
Results The dermoscopic vascular structures seen in NTD consisted of round dotted and globular vessels, linear vessels and glomerular vessels. In addition, structureless coloured patches were also found. In some NTD the distribution of the vascular structures took on special arrangements. The most common vascular findings were the linear and the rounded vessels, which were distributed either homogeneously throughout the lesion or were present together with other vascular or pigmented features in a mixed pattern.
Conclusion The present study proposes a new classification of dermoscopic vascular features based on the screening of a large spectrum of nontumoral dermatoses. This list may be useful to define further dermoscopic semiology and to understand the vascular features most relevant to the diagnosis not only of different NTD but also of pigmented and amelanotic melanoma.
In this paper, a new approach to computer supported diagnosis of skin tumors in dermatology is presented. High resolution skin surface profiles are analyzed to recognize malignant melanomas and ...nevocytic nevi (moles), automatically. In the first step, several types of features are extracted by 2D image analysis methods characterizing the structure of skin surface profiles: texture features based on cooccurrence matrices, Fourier features and fractal features. Then, feature selection algorithms are applied to determine suitable feature subsets for the recognition process. Feature selection is described as an optimization problem and several approaches including heuristic strategies, greedy and genetic algorithms are compared. As quality measure for feature subsets, the classification rate of the nearest neighbor classifier computed with the leaving-one-out method is used. Genetic algorithms show the best results. Finally, neural networks with error back-propagation as learning paradigm are trained using the selected feature sets. Different network topologies, learning parameters and pruning algorithms are investigated to optimize the classification performance of the neural classifiers. With the optimized recognition system a classification performance of 97.7% is achieved.
Based on the skin cancer screening model of Germany a critical statement is presented about skin cancer epidemiology, the total body examination and time intervals. The number of skin cancer cases ...will increase and the number of dermatologists will probably decrease; thus a fundamental and pragmatic strategy is required for further education and planning to comply with the increased dermato-oncological demand of an aging population. Hereby dermoscopy should be a basic diagnostic tool for the early recognition of skin cancer and precursors as well as to avoid unnecessary excisions of benign skin lesions. The excision ratio between malignant and benign skin tumours should be optimized.
Dermoscopy has a high diagnostic accuracy in pigmented and nonpigmented malignant and benign skin tumors. These microscopic in vivo examinations with polarized and nonpolarized light are effective in ...the early detection of malignant skin tumors and reduce the number of unnecessary excisions of benign skin tumors. The selection of the skin lesions is crucial for the diagnostic accuracy of the dermoscopic examination. Not only large pigmented skin lesions, but also small hypo-, de-, or nonpigmented skin lesions, should be examined dermatoscopically as well as skin lesions that have changed in shape and/or color. In clinical routine, research and teaching, the dermoscopic diagnosis should be performed by describing the visible structures, their distribution and colors by means of descriptive and/or metaphoric terminology. Optionally, a diagnostic algorithm can also be used. Especially in benign lesions, the dermatoscopic diagnosis should be uniform for the complete area. Comparison with other nearby skin tumors of the same patient (comparative approach) is helpful in the evaluation of numerous melanocytic skin tumors. If it is unclear whether the lesion is malignant, a biopsy or complete excision should be performed with subsequent histopathological examination.
The use of dermoscopy by dermatologists across Europe has become a standard examination for benign and malignant skin lesions and increasingly also for inflammatory skin diseases. However, based on ...the experience of the authors from numerous dermoscopy courses, knowledge about important dermoscopic features in special locations such as mucosa or nails is often limited. This may be explained by (1) a different anatomy of the skin and its adnexa in special locations in comparison to the remaining integument, (2) difficult technical access to special locations with a dermatoscope, and (3) a rather low incidence of malignant skin neoplasms in areas of special locations (with the exception of facial skin/scalp). This article aims at explaining dermoscopic characteristics and features of important benign and malignant lesions of nails, acral skin, face, and mucosa.
Summary
The good efficacy and tolerability of an alcoholic erythromycin/tretinoin solution was confirmed in a multicentre data investigation of over 6500 patients. The mean score for comedones ...declined clearly from 1.9 to 0.9 during treatment (average duration 70 days). The score for papules and pustules was reduced from 1.6 to 0.5. Overall medical assessment indicated ‘very good’ to ‘good’ efficacy in 86.1% of documented cases. Adverse drug reactions during treatment were mostly only very mild and were nearly always the known symptoms of redness, scaling, dryness and itching. Overall assessment of tolerability was ‘very good’ or ‘good’ in 88.1% of cases.
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