title: Dynamic viscoelastic models of human skin using optical elastography.
abstract: A novel technique for measuring in vivo human skin viscoelastic properties using optical elastography has been developed. The technique uses geometrically focused surface (GFS) waves that allow for wide bandwidth measurements of the wave field. An analytical solution for the case of a radiating annular disk surface source was fit to experimentally measured GFS waves, enabling an estimate of the frequency-dependent surface wavenumber, which can then be related to the dynamic shear modulus. Several viscoelastic models were then fit to the dynamic shear modulus dispersion curve. Viscoelastic models were evaluated based on their overall quality of fit and variability amongst healthy volunteers. An Ecoflex phantom was used to validate the procedure and results by comparison to similar studies using the same type of phantom. For skin results, it was found that the 'α' parameters from the fractional models had the least variability, with coefficients of variability of 0.15, and 0.16. The best fitting models were the standard linear solid, and the fractional Voigt, with a mean fit correlation coefficient, R(2), of 0.93, 0.89, respectively. This study has demonstrated the efficacy of this new method, and with larger studies the viscoelastic skin models could be used to identify various skin diseases and their response to treatment.
authors: Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, 842 West Taylor Street MC 251, Chicago, IL 60607-7052, USA.
authors: Steven P
authors: SP
authors: Kearney
authors: Altaf
authors: A
authors: Khan
authors: Zoujun
authors: Z
authors: Dai
authors: Thomas J
authors: TJ
authors: Royston
mesh_terms: D000328:Adult; D003198:Computer Simulation; D055119:Elastic Modulus / Q000502:physiology*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D012867:Skin / Q000378:metabolism*; D014783:Viscosity