Figure 5: SM-OCT in the mouse pinna reveals fine low-contrast structures.

(a,b) OCT and SM-OCT B-scans of a mouse pinna. Scale bar, 100 μm. (c,d) Close-up views on the regions marked in a,b. The arrows in d depict an anatomical feature the size of 9.1 μm that is not visible in the OCT image. Scale bar, 100 μm. (e,f) Close-up views on the regions marked in a,b. The arrow in f shows a dark line, which is 2 μm thick. Scale bar, 50 μm. (g,h) OCT and SM-OCT en face scans at the depth indicated by the dashed line in c,d. The SM-OCT image in h shows lymph vessels (black arrow) and fine structures (yellow arrow) that are nearly invisible in g. Scale bar, 200 μm. (i) Microscope image of a haematoxylin and eosin (H&E)-stained mouse ear pinna at 10 × magnification. Scale bar, 100 μm. (j) Manual segmentation of the ear volume is possible owing to the removal of speckle noise, revealing the structure of hair follicles (Supplementary Movie 3). Cyan—epidermis, grey—auricular cartilage, magenta—lymph vessels, red—sebaceous glands, blue—follicle bulb, yellow—follicle shaft, green—unidentified part of the follicle.