Fig. 1

Representative ultrasonic and histological skin images of a patient with systemic sclerosis. In an ultrasound B-mode image (a) or a hematoxylin and eosin-stained image (b), the distance from the outermost epidermis to the interface between the dermis and subcutis was measured as skin thickness. Representative measurements were shown by dotted lines. To quantify skin stiffness, shear wave elastography mode was activated and a color-coded elastogram was superimposed on the B-mode image; the epidermis and dermis layers were traced, and the mean elastic modulus value of the trace area (the dotted box) was automatically calculated by the ultrasound system (c)