100 MHz sonography of psoriasis vulgaris plaques.

Purpose: 20 MHz sonography of inflammatory diseases has concentrated on the evaluation of the echo-poor area in the upper dermis. With regard to highe r resolution, this study focuses on the alterations of the epidermis and up per dermis skin using 100 MHz sonography. Method: 70 fully developed psoria sis vulgaris plaques of 20 patients were examined using our 100 MHz ultraso und equipment after application of salicylic acid in petrolatum for 24 h. A fter informing the patient about the aims of the study, a small knife biops y was taken from 11 plaques. Results: All psoriasis plaques exhibited, in c omparison with normal skin, a significant widening of the skin entry echo ( p < 0.001). Focally, this echo-rich line broke up into two thinner lines. C orrelating histology exhibited in these areas an orthohyperkeratosis and fo cal parakeratosis. The upper dermis showed an echo-poor, band-shaped area w hich corresponded histologically to an acanthosis, elongation of rete ridge s, and widening of the stratum papillare. The mean grey level of the echo-p oor area and of the dermis beneath was significantly lower (p<0.001) than t he normal adjacent dermis. The thickness of the echo-poor area correlated w ith the thickness of the sum of the acanthosis and the inflammatory infiltr ate in the histological sections (r = 0.94). Conclusion: Using 100 MHz sono graphy changes of the skin entry echo and the upper dermis can be visualize d and quantified.