ECHOGRAPHIC EVALUATION WITH IMAGE-ANALYSIS OF NORMAL SKIN - VARIATIONS ACCORDING TO AGE AND SEX

In order to identify and characterize the sonographic variations betwe en different age groups, 48 subjects, 24 aged 27-30, and 24 over 60, w ere studied with a 20-MHz B scanner on six skin sites. Images were eva luated by the instrument's standard programme and by a new image analy sis software package enabling the characterization of steady structure s or transitory functional aspects of skin reactions, by highlighting areas in which the echo amplitudes are included within selected values , and by calculating their extension. Three bands were selected as int ervals of interest, respectively, highlighting hyporeflecting parts of the dermis, tissue reflecting with intermediate amplitude values and hyperreflecting epidermis and dermis. This method was employed to asse ss skin thickness, demonstrating its decrease in elderly skin, to char acterize and quantify the hypoechogenic subepidermal band appearing in the elderly at volar and dorsal forearm skin, and to evaluate echogen icity of the upper and lower dermis. Our data show that there is a gre at regional variation in the behaviour of ultrasound reflection of eld erly skin in respect to the skin of young subjects. However, a general trend can be identified, consisting in a shift from low-intensity ult rasound echoes, characteristic in the dermis of young subjects, to int ermediate or high reflection amplitudes, which are more frequent in el derly skin. Thus, the echographic method provides two parameters for t he evaluation of skin aging. Besides an accurate and early assessment of skin atrophy, it also enables an evaluation of physical properties of the skin, which do not influence the morphological aspect in micros copy, but induce variations of the acoustic behavior which are express ed by a modification of the reflectivity to ultrasound.