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The ablative fractional coagulation zone influences skin fluorescence intensities of topically applied test molecules-An in vitro study with fluorescence microscopy and fluorescence confocal microscopy
摘要： Background: Ablative fractional laser (AFL) increases uptake of topically applied skin agents. The coagulation zone (CZ) surrounding vertically ablated channels may influence uptake of drugs. Objectives: To investigate impact of CZ thickness on skin fluorescence intensities (FI) of a hydrophilic molecule by means of fluorescence microscopy (FM) and fluorescence confocal microscopy (FCM). Second, to compare FI of hydrophilic and lipophilic test molecules by FCM. Study Design/Methods and Materials: Microchannels with CZ thicknesses of 0, 20, and 80 μm were generated by microneedles or AFL (10,600 nm). Channels were 700 μm deep and number of channels kept constant per skin area. After 4 hours of incubation, FI induced by sodium fluorescein (NAF, hydrophilic, logarithmic partition-coefficient (logP) = -1.52, MW = 376.26) were quantified in both CZ and surrounding skin by FM (0–1,500 μm) and FCM (0–90 μm). FI of NAF and carboxyfluorescein (CAF, lipophilic, logP = 2.9, MW = 376.32) were compared by FCM. Results: By FM, NAF-induced FI were higher in CZ than in surrounding skin (P ≤ 0.001). Highest NAF-FI were induced in skin pretreated with a thin CZ (CZ–20 μm), assessed by both FM and FCM and in particular, FI were higher than in skin pretreated with no CZ (CZ–0 μm) (FM P ≤ 0.041, FCM P < 0.012). Skin FI remained constant to a depth of 500 μm, which corresponded to approximate depth of microchannels (CZ–0 μm, CZ–20 μm, CZ–80 μm: 0–500 μm P ≥ 0.107). In accordance with FM data, FCM showed higher FI within CZ than in surrounding skin, but gradually decreased to zero at a depth of 90 μm. NAF-FI were higher than CAF-FI (P ≤ 0.036), and highest CAF-FI were induced by CZ–0 μm and CZ–20 μm compared to CZ–80 μm (P ≤ 0.009). Conclusions: The influence of the CZ thickness on skin FI differs between small hydrophilic and lipophilic test molecules. Results may have clinical relevance for laser-assisted drug delivery.
关键词： sodium fluorescein,reflectance,carboxyfluorescein,dermatology,drug delivery,skin imaging
更新于2025-09-23 15:23:52
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Novel Use of Nona??Invasive Devices and Microbiopsies to Assess Facial Skin Rejuvenation Following Laser Treatment
摘要： Patient‐reported outcomes and blinded observer rating scales are subjective and unreliable but are extensively utilized to evaluate cosmetic office‐based treatments, including ablative lasers. This study aims to assess the practicality of using non‐invasive and minimally invasive methods for objective skin assessment following a skin rejuvenation treatment. Twelve patients received a single 1,470/2,940 nm laser treatment for facial rejuvenation. Assessments were performed before treatment, and 7 days, 3 weeks, and 3 months post‐treatment. Images were taken with the VISIA Skin Analysis System to measure wrinkles, textures, pores, ultraviolet (UV) spots, brown spots, red areas, and porphyrins. Other non‐invasive skin measurements—high‐resolution ultrasonography, optical coherence tomography, transepidermal water loss and BTC 2000—were used to measure epidermal/dermal thickness, blood flow, surface roughness, wrinkle depth, attenuation coefficient, elasticity, viscoelasticity. Microbiopsies (0.33 mm in diameter or the equivalent of a 23‐gauge needle) were collected for histology and gene expression of tissue rejuvenation. Significant improvement in facial skin aesthetics after laser treatment was recorded in UV spots, brown spots and pores after 3 weeks and in UV spots and brown spots after 3 months. The dermal attenuation coefficient decreased significantly at 3 weeks, while blood flow 0.5 to 0.7 mm below the skin surface increased significantly between 5 days and 3 weeks following treatment. Epidermal hyaluronic acid expression assessed by immunostaining and expression of inflammatory genes were elevated at 7 days post‐treatment compared with untreated or 3 months post‐treatment. There were no statistically significant changes in collagen or elastin‐related genes between groups at the studied parameters. Non‐invasive devices can be effectively used to provide objective measurements of skin structure, pigmentation, blood flow, and elasticity to assess the efficacy of facial skin rejuvenation treatments. Furthermore, microbiopsies can objectively evaluate facial skin rejuvenation without scarring. Using non‐invasive skin imaging, a single treatment with the 1,470/2,940 nm laser was observed to be effective in improving skin appearance after 3 months, namely in reducing UV spots and brown spots, without significant changes in the tissue at the molecular level, as assessed by microbiopsy.
关键词： non‐invasive,laser ablation,microbiopsy,skin biopsy,skin rejuvenation,skin imaging
更新于2025-09-23 15:19:57
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Optical coherence tomography angiography and photoacoustic imaging in dermatology
摘要： Optical coherence tomography angiography (OCTA) is a relatively novel functional extension of the widely accepted ophthalmic imaging tool named optical coherence tomography (OCT). Since OCTA’s debut in ophthalmology, researchers have also been trying to expand its translational application into dermatology. The ability of OCTA in resolving microvasculature has shown promising results in imaging skin diseases. Meanwhile, photoacoustic imaging (PAI), which uses laser pulse induced ultrasound waves as the signal, has been studied to differentiate human skin layers and to help skin disease diagnosis. This perspective article gives a short review of OCTA and PAI in the field of photodermatology. After an introduction of the principles of OCTA and PAI, we describe the most updated results of skin disease imaging using these two optical imaging modalities. We also put an emphasis on dual modality imaging combining OCTA and photoacoustic tomography (PAT) for dermatological applications. In the end, the challenges and opportunities of these two imaging modalities in dermatology are discussed.
关键词： microvasculature,dermatology,Optical coherence tomography angiography,photoacoustic imaging,skin imaging
更新于2025-09-19 17:15:36
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Accurate depth estimation of skin surface using a light-field camera toward dynamic haptic palpation
摘要： Background: Haptic skin palpation with three-dimensional skin surface reconstruction from in vivo skin images in order to acquire both tactile and visual information has been receiving much attention. However, the depth estimation of skin surface, using a light field camera that creates multiple images with a micro-lens array, is a difficult problem due to low-resolution images resulting in erroneous disparity matching. Methods: Multiple low-resolution images decoded from a light field camera have limitations to accurate 3D surface reconstruction needed for haptic palpation. To overcome this, a deep learning method, Generative Adversarial Networks, was employed to generate super-resolved skin images that preserve surface detail without blurring, and then, accurate skin depth was estimated by taking multiple subsequent steps including lens distortion correction, sub-pixel shifted image generation using phase shift theorem, cost-volume building, multi-label optimization, and hole filling and refinement, which is a new approach for 3D skin surface reconstruction. Results: Experimental results of the deep-learning-based super-resolution method demonstrated that the textural detail (wrinkles) of super-resolved skin images is well preserved, unlike other super-resolution methods. In addition, the depth maps computed with our proposed algorithm verify that our method can produce more accurate and robust results compared to other state-of-the-art depth map computation methods. Conclusion: Herein, we first proposed depth map estimation of skin surfaces using a light field camera and subsequently tested it with several skin images. The experimental results established the superiority of the proposed scheme.
关键词： depth estimation,skin imaging,disparity estimation,dermatology,light field camera,haptic palpation
更新于2025-09-19 17:15:36