title: Clinical nonlinear laser imaging of human skin: a review.
abstract: Nonlinear optical microscopy has the potential of being used in vivo as a noninvasive imaging modality for both epidermal and dermal imaging. This paper reviews the capabilities of nonlinear microscopy as a noninvasive high-resolution tool for clinical skin inspection. In particular, we show that two-photon fluorescence microscopy can be used as a diagnostic tool for characterizing epidermal layers by means of a morphological examination. Additional functional information on the metabolic state of cells can be provided by measuring the fluorescence decay of NADH. This approach allows differentiating epidermal layers having different structural and cytological features and has the potential of diagnosing pathologies in a very early stage. Regarding therapy follow-up, we demonstrate that nonlinear microscopy could be successfully used for monitoring the effect of a treatment. In particular, combined two-photon fluorescence and second-harmonic generation microscopy were used in vivo for monitoring collagen remodeling after microablative fractional laser resurfacing and for quantitatively monitoring psoriasis on the basis of the morphology of epidermal cells and dermal papillae. We believe that the described microscopic modalities could find in the near future a stable place in a clinical dermatological setting for quantitative diagnostic purposes and as a monitoring method for various treatments.
authors.affiliation: National Institute of Optics (INO), National Research Council (CNR), Largo E. Fermi 6, 50125 Florence, Italy ; European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy.
authors.forename: Riccardo
authors.identifier: 0000-0002-2583-6694
authors.initials: R
authors.lastname: Cicchi
authors.affiliation: European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy.
authors.forename: Dimitrios
authors.identifier: 0000-0001-5576-2406
authors.initials: D
authors.lastname: Kapsokalyvas
authors.affiliation: National Institute of Optics (INO), National Research Council (CNR), Largo E. Fermi 6, 50125 Florence, Italy ; European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy ; Department of Physics, University of Florence, Via Giovanni Sansone 1, 50019 Sesto Fiorentino, Italy.
authors.forename: Francesco Saverio
authors.initials: FS
authors.lastname: Pavone
mesh_terms: D046169:Dermoscopy / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007834:Lasers; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D017711:Nonlinear Dynamics; D012867:Skin / Q000473:pathology*; D012871:Skin Diseases / Q000473:pathology*