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Background Line-field confocal optical coherence tomography (LC-OCT) is a non-invasive optical technique recently developed for skin examination in vivo. It provides real-time, high-resolution vertical images with an isotropic resolution of similar to 1 mu m and a penetration depth of similar to 500 mu m. Objectives Study goals were to qualitatively/quantitatively characterize healthy skin at different body sites using LC-OCT. Methods The skin of young healthy volunteers was imaged with a handheld LC-OCT imaging device. Seven body sites (back of the hand, forehead, cheek, nose, chest, forearm and back) were investigated. An independent qualitative [cutaneous structures' description; visibility of keratinocytes' nuclei and dermal-epidermal junction (DEJ)] and quantitative [stratum corneum (SC)/epidermal thicknesses; height of dermal papillae] assessment of the LC-OCT images was performed. Results A total of 88 LC-OCT images were collected from 29 participants (20 females; nine males; mean age 25.9 years). Keratinocytes' nuclei and DEJ were visible in the totality of images. The different layers of the epidermis and the remaining cutaneous structures/findings were visualized. Body sites-related variability was detected for SC/epidermal thicknesses and height of dermal papillae. Inter-observer agreement was excellent (SC thickness), good-to-excellent (epidermal thickness) and moderate-to-good (papillae). Conclusions Line-field confocal-OCT provides non-invasive, real-time imaging of the skin in vivo with deep penetration and high resolution, enabling the visualization of single cells. The histology-like vertical view provides an easy way to recognize/measure different cutaneous structures/findings. LC-OCT appears as a promising technique for the examination of physiological/pathological skin.

The use of non-invasive imaging techniques in dermatology has been reported to improve the diagnostic accuracy and the practice of biopsies, and at the same time to reduce the need for tissue excision. However, the current clinically-available imaging techniques do not yet entirely meet the need for early and accurate, non-invasive detection of all skin cancers. A handheld line-field confocal optical coherence tomography (LC-OCT) device has been designed for high-resolution non-invasive imaging of human skin, in vivo. LC-OCT delivers tomographic images in real-time (10 frames/s) with a quasi isotropic spatial resolution of ~ 1 μm, revealing a comprehensive morphological mapping of skin tissues at a cellular level, down to a depth of ~500 μm. The device has been applied to the in vivo imaging of various skin lesions. Surgical excisions of the lesions have then been performed followed by tissue processing to realize H&E-stained histopathological images. The spatial resolution, orientation, and imaging contrast mechanism of the LC-OCT images have allowed for a good level of similarity with the conventional histopathological images. LC-OCT was able to show most of the histopathological elements that allow for medical diagnosis. Using handheld LC-OCT as an adjunct tool in dermatology could help improve clinical diagnostic accuracy, allowing for the early detection of malignant skin tumors and a reduction in the number of surgical excisions of benign lesions.

An improved optical coherence tomography (OCT) technique called line-field confocal OCT (LC-OCT) has been developed for high-resolution skin imaging. Combining the principles of time-domain OCT and confocal microscopy with line illumination and detection, LC-OCT acquires multiple A-scans in parallel with dynamic focusing. With a quasi isotropic resolution of ∼ 1 μm, the LC-OCT images reveal a comprehensive structural mapping of skin, in vivo, at the cellular level down to a depth of ∼ 500 μm. LC-OCT images of various skin lesions, including carcinomas and melanomas, are found to well correlate with histopathological images. LC-OCT could significantly improve clinical diagnostic accuracy, while reducing the number of biopsies of benign lesions.

An optical technique called line-field confocal optical coherence tomography (LC-OCT) is introduced for high-resolution, noninvasive imaging of human skin in vivo. LC-OCT combines the principles of time-domain optical coherence tomography and confocal microscopy with line illumination and detection using a broadband laser and a line-scan camera. LC-OCT measures the echo-time delay and amplitude of light backscattered from cutaneous microstructures through low-coherence interferometry associated with confocal spatial filtering. Multiple A-scans are acquired simultaneously while dynamically adjusting the focus. The resulting crosssectional B-scan image is produced in real time at 10 frame/s. With an isotropic spatial resolution of ∼1 μm, the LC-OCT images reveal a comprehensive structural mapping of skin at the cellular level down to a depth of ∼500 μm. LC-OCT has been applied to the imaging of various skin lesions, in vivo, including carcinomas and melanomas. LC-OCT images are found to strongly correlate with conventional histopathological images. The use of LC-OCT as an adjunct tool in medical practice could significantly improve clinical diagnostic accuracy while reducing the number of biopsies of benign lesions., SCOPUS: ar.j, info:eu-repo/semantics/published

International audience; Multispectral and hyperspectral imaging are imaging modalities that collect more physical information than conventional color imaging, allowing detailed study of material properties. Applied to skin, these imaging methods enable noninvasive, pixel-by-pixel surface measurements, making them promising tools for in vivo skin study. In particular, skin spectral images can be analyzed using physics-based models, or artificial intelligence combined with databases. A typical application is the estimation of information such as melanin concentration and total blood volume fraction from a model-based approximation of skin structure and composition and a model of light–skin interaction.