Analysis of Factors Affecting Shear Wave Speed in in vivo Skin

In 10 patients with cutaneous sclerotic skin conditions, shear wave elasticity imaging (SWEI) was used to measure shear wave speed in the skin in vivo. The dermis was segmented using an thresholding-based algorithm and group speeds were found in both the dermis and the subcutaneous tissue. Phase velocities were calculated in the layer, and a linear regression was fit to obtain a dispersion slope. A statistically significant non-zero dispersion was found in the skin in vivo. An ordinary least squares multiple linear regression was performed to assess what factors affected the dispersion slope. Thickness did not have a statistical effect on the dispersion slope in each model, and subcutaneous speed was only found to have a statistical effect at one of two investigated frequency-thickness products. This work shows SWEI based dispersion in the skin in vivo and demonstrates the importance of subcutaneous speed in future models.