Fig. 1: Computation pipeline of skin biomarkers from RSOM images.

a Schematic of the RSOM system employed for skin measurements, comprising two fiber bundles for illumination and a high frequency ultrasound transducer (UT) that was raster scanned over the skin surface. RSOM signals are recorded on the pretibial area of the lower extremities of both healthy volunteers and participants with diabetes, after which volumetric image reconstruction (IR) is performed. b A reconstructed RSOM volume image. The volumetric RSOM image is segmented (IS) to identify the epidermis layer and dermal vasculature, which are used to subsequently compute biomarkers. c Segmentation of the cross-sectional RSOM image into the epidermis (EP) and dermis (DR) layers of the skin (white dashed lines). The EP thickness and EP signal density biomarkers were computed from the segmented EP layers in the RSOM images. d Vessel segmentation of the segmented DR layer of the skin. The numbers of vessel branches and vessel diameters were automatically calculated; the red dots indicate positions of vessel branches. The segmented vessels in the DR were used to calculate the vessel numbers and total blood volume biomarkers. IR image reconstruction, IS image segmentation, VS vessel segmentation, BC biomarker computation, scale bar = 500 µm