Appareil d'évaluation in vivo des propriétés rhéologiques du revêtement cutané par technique ultrasonore

In certain dermatoses, the mechanical properties of the skin are markedly altered. The evaluation of these properties in-vivo requires equipment which can simultaneously measure the skin's thickness while applying a known stress to the site in question. Skin thickness can be measured with either A- or B-scan mode ultrasound, the former of which we have incorporated in a device with enables skin elasticity to be determinated. Essentially, this involves the measurement of the distance between transducer (20 Mhz) and the skin structures, before and after deformation by suction, with a resolution of 70 µm. The transducer is located inside a small, cylindrical chamber, which has a 6 mm diameter aperture below the transducer to allow contact with the skin. This device can determine, in a non-invasive way, not only which skin structures are involved in this deformation, but also the morphological variation in the subcutaneous layers and their level of involvement at different stresses. With such information, we hope to be able to propose a mechanical model and to define appropriate skin rheological parameters