1,721,183 research outputs found
Line‐field confocal optical coherence tomography: practical applications in dermatology and comparison with established imaging methods
Get PDFBackground Non-invasive diagnostic techniques in dermatology gained increasing popularity in the last decade. Reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) are meanwhile established in research and clinical routine. While OCT is mainly indicated for detecting non-melanoma skin cancer, RCM has proven its usefulness additionally in distinguishing melanocytic lesions. Line-field confocal optical coherence tomography (LC-OCT) is an emerging tool combining the principles of both above-mentioned methods. Methods Healthy skin at different body sites and exemplary skin lesions (basal cell carcinoma, malignant melanoma, actinic keratosis) were examined using dermoscopy, RCM, OCT and LC-OCT. Standard features for RCM and OCT and comparable features for LC-OCT were analysed. Results LC-OCT has a lower penetration depth but superior resolution compared to OCT. In comparison with RCM, which provides only horizontal sections, LC-OCT creates both vertical and horizontal images in real time and has nearly the same cellular resolution. Discussion Our preliminary experiences suggest that LC-OCT combines the advantages of RCM and OCT, with optimal resolution and penetration depth to diagnose all types of skin cancer. Larger systematic studies are needed to further characterize the field of use of this device and its sensitivity and specificity compared to histology
Dynamic optical coherence tomography is a new technique for imaging skin around lower extremity wounds
No full textChronic wounds such as venous leg ulcers invariably heal slowly and recur. In the case of venous leg ulcers, poor healing of chronic wounds is variously attributed to ambulatory hypertension, impaired perfusion and diffusion, presence of chronic inflammation at wound sites, lipodermatosclerosis, and senescence. The aim of this study was to investigate whether a new technique, optical coherence tomography (OCT), which permits imaging of blood capillaries in the peri-wound skin, can provide new insights into the pathology. OCT and its recent variant, dynamic OCT, permit rapid noninvasive depth-resolved imaging of the capillaries in the superficial dermis via a handheld probe, showing the morphology and density of vessels down to 20 µm in diameter. We used dynamic OCT to investigate 15 chronic wounds and assess characteristics of the vessels at the 4 poles around the wounds, the wound bed, adjacent dermatosclerosis, and unaffected skin. The results of the study show that both vessel morphology and density in the wound edges are dramatically different from that in healthy skin, showing clusters of glomuleri-like vessels (knot-like forms or clumps) and an absence of linear branching vessels, and also greater blood perfusion. Such vessel shapes are reported to be associated with tissue growth. The OCT imaging procedure was rapid and well tolerated by patients and provided new information not available from other devices. Thus, OCT appears to have great promise as a tool for the evaluation and study of chronic ulcers.</p
Tumor Penetrative Depth Considers Both the Size of Sentinel Lymph Node Metastases and Their Location in Relation to the Nodal Capsule
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
non-invasive analysis of vascular parameters
No full textDynamische Optische Kohärenztomographie Melanozytärer Läsionen : Nicht-invasive Analyse von GefäßparameternThe differential diagnosis of melanocytic lesions is of great importance due to the
rise in melanoma incidence, high morbidity and mortality in later stages and
demanding differential diagnosis, especially in early stages. Currently, by a clinical-
dermoscopic approach, early melanomas may be overlooked, the proportion of
melanomas and dysplastic nevi overestimated, and a significant number of
performed biopsies may be unnecessary.
This prospective, clinical, multicentre study investigated the potential of dynamic
optical coherence tomography (D-OCT) to distinguish melanocytic lesions based on
their microvascularisation. The study hypothesis was the existence of vascular
differences between nevi, dysplastic nevi, melanomas, adjacent skin and according
to potential influencing factors, including age, sex, and lesion location. The results
were compared to the current diagnostic gold standard of a clinical-dermoscopic
and histological examination. Further, to confocal laser microscopy and line-field
confocal optical coherence tomography.
With excellent predictive values, D-OCT distinguished nevi from melanomas.
Several significant and explainable differences were observed concerning nevus
subtypes, participant sex, age and lesion location but allowed no solely vascular-
based distinction. Based on our findings, we created an algorithm to standardise a
D-OCT-based differential diagnosis of melanocytic lesions.
Improving the current clinical-dermoscopic diagnostic approach and avoiding
invasive biopsies are central research interests. D-OCT visualises skin morphology
and vascularisation in vivo and in real time. Its non-invasive approach prevents
unnecessary biopsies, wound formation, infection, scarring and biopsy-related pain.
It has a high resolution and appropriate penetration depth. Scanning is quick,
handling is simple, and it is suitable for the skin of every ethnicity and all lesion
locations and architectures. Furthermore, it offers an individualised therapeutic
approach and a potentially earlier melanoma detection with a consequent reduction
of morbidity and mortality and an economic benefit.
Further confirmation by high-quality, multicentric studies is recommended. If
promising, a combinatory device with D-OCT, camera, and dermoscopy tool should
be considered for diagnosing (unclear) melanocytic lesions
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Messung von Hautatropie unter vierwöchiger topischer Anwendung verschiedener Glukokortikosteroide mit optischer Kohärenztomographie, Ultraschall und Profilometrie
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