Multi-wave dermis characterization using attenuation coefficient and shear wave speed estimates in vivo

Skin characterization is of importance for disease diagnosis and treatment follow-up. In particular, estimation of the biomechanical properties is useful for wound healing monitoring. This study proposes and validates for the first time the use of multi-wave quantitative ultrasound (MWQUS) as a skin characterization tool via the estimation of attenuation coefficient slope (ACS) and shear wave speed (SWS) in vivo based on the regularized spectral-log difference technique (RSLD) and crawling wave sonoelastography (CrW). Nine volunteers without skin injuries (age range of 19-30 years) were scanned in the middle of the dorsal side of the forearm. The median of the ACS and SWS were 1.93 dB·cm
^-1
·MHz
^-1
and 3.24 m/s, respectively, which are in good agreement with previous reports in the literature. Results showed a decreasing trend of the SWS with increasing ACS with a statistically significant (p = 0.01) Pearson correlation coefficient of -0.79. The importance of the results presented here lies in that the observed variability in the estimates appears to stem from biological variability jointly explained by both ACS and SWS parameters. These results suggest that both methodologies (RSLD and CrW) can be applied together for a more complete, comprehensive multi-wave QUS characterization of the skin and provide estimates that are sensitive to changes in dermal composition.