RESUMEN
BACKGROUND: One major sequelae of acne is atrophic scarring, yet objective tools to assess scars are lacking. Neither depth nor volume of atrophic scars is readily evaluable clinically and standard 2D photography is significantly affected by lighting and shadows. The aim of our study was to define and evaluate parameters of 3D imaging that can be used to assess severity of atrophic acne scarring. METHODS: Single center study of 31 patients with acne scarring. A target area of 3 × 3 cm was defined on the face. The global severity of atrophic acne scarring in the target area was evaluated by 5 dermatologists and scars were counted and categorized by size (scars < 2 mm, 2-4 mm, and > 4 mm in diameter). Three dimensional images of the target area were acquired with the LifeViz Micro® system and analysis was performed using MountainsMaps® software. An algorithm was developed to quantify the scar volume loss: shape removal step, with an order 5 polynomial, and to calculate the Valley void volume 80% (Vvv 80%) defined in the ISO-25178 standard for 3D surface texture. RESULTS: Correlation coefficient of the Vvv parameter to mean global severity at the target area rating was 0.77. The volume of scars evaluated with the Vvv parameter was mainly impacted by scars > 2 mm. The evaluations demonstrated good repeatability (with an intra-class correlation coefficient ICC = 0.98). CONCLUSIONS: We demonstrate convergent validation to clinical assessment and repeatability of 3D skin imaging in atrophic acne scarring. Image analysis is straightforward and can be integrated into an automated workflow.
Asunto(s)
Acné Vulgar/patología , Cicatriz/diagnóstico por imagen , Imagenología Tridimensional , Fotograbar , Piel/diagnóstico por imagen , Acné Vulgar/complicaciones , Adolescente , Adulto , Anciano , Algoritmos , Atrofia , Cicatriz/clasificación , Cicatriz/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Índice de Severidad de la Enfermedad , Piel/patologíaRESUMEN
BACKGROUND: Currently, imaging technologies that can accurately assess or provide surrogate markers of the human cutaneous microvessel network are limited. Dynamic optical coherence tomography (D-OCT) allows the detection of blood flow in vivo and visualization of the skin microvasculature. However, image processing is necessary to correct images, filter artifacts, and exclude irrelevant signals. The objective of this study was to develop a novel image processing workflow to enhance the technical capabilities of D-OCT. MATERIALS AND METHODS: Single-center, vehicle-controlled study including healthy volunteers aged 18-50 years. A capsaicin solution was applied topically on the subject's forearm to induce local inflammation. Measurements of capsaicin-induced increase in dermal blood flow, within the region of interest, were performed by laser Doppler imaging (LDI) (reference method) and D-OCT. RESULTS: Sixteen subjects were enrolled. A good correlation was shown between D-OCT and LDI, using the image processing workflow. Therefore, D-OCT offers an easy-to-use alternative to LDI, with good repeatability, new robust morphological features (dermal-epidermal junction localization), and quantification of the distribution of vessel size and changes in this distribution induced by capsaicin. The visualization of the vessel network was improved through bloc filtering and artifact removal. Moreover, the assessment of vessel size distribution allows a fine analysis of the vascular patterns. CONCLUSION: The newly developed image processing workflow enhances the technical capabilities of D-OCT for the accurate detection and characterization of microcirculation in the skin. A direct clinical application of this image processing workflow is the quantification of the effect of topical treatment on skin vascularization.