Figure 6.

(a) The total intensity was measured by high‐frequency ultrasound (HFUS), which corresponds to the dermal density or echogenicity of the skin. Lower numbers or thinner collagen fibres can reflect a weaker echo than thicker collagen fibres, which provide a stronger echo. The measurements showed a significant reduction in echogenicity from day 0 (uninjured skin) (42%) to week 8 (29%) (P = 0·02). (b) The optical coherence tomography (OCT) attenuation coefficient is the amount by which the optical signal reduces with distance travelled into the skin, and has been related to collagen density and organization. The attenuation coefficient significantly reduced from uninjured skin [2·2 arbitrary units (Au)] to week 8 (1·35 Au) (P < 0·001).