Epidermal echogenicity as a hydration parameter: The effect of moisturizers on the skin as evaluated by 20 MHz B-scanning

Hydration of the stratum corneum after a short-term application of three skin-care products (petrolatum and two different moisturizers) was studied on the forearms of 15 healthy volunteers. Non-invasive methods were used. Evaporimetry, corneometry and B-scanning were carried our at the beginning, immediately after removal of the test chamber, and 15, 30, 60, 120, and 180 minutes later. Echographic recordings were performed by 20 MHz B-scanning and processed by a dedicated software (Dermavision 2D, Cortex Technology, Hadsund, Denmark) based on the selection of amplitudes of interest and segmentation procedures. Segmentation of the images was performed employing two amplitude intervals, respectively highlighting hyper-reflecting (epidermis, lower pare of dermis) and hypo-echogenic parts of the tissue. The evaluation of the dermis showed an attenuation of the hyper-reflecting areas of the deep dermis for all three substances and a significant decrease in echogenicity for petrolatum alone. Superficial hyper-reflecting areas assessing epidermis were significantly reduced in respect to baseline, at all assessment times for all three products. This echographic aspect corresponded to increased capacitance values, which were recorded for up to 180 minutes. In conclusion, 20 MHz B-scanning evaluation represents a valid support for the assessment of skin hydration