Imaging of the skin with 20-MHz US.

Abstract

The authors clinically evaluated a new high-frequency ultrasound (US) scanner to determine the value of US for dermatologic applications. A 20-MHz US scanner was used to visualize normal skin at eight sites in 10 healthy volunteers and to evaluate 200 skin lesions (45 malignant, 155 benign). In normal skin, the dermis was markedly echogenic and sharply demarcated from hypoechoic subcutaneous fat. The epidermis was not resolved except on the palm and sole. Only three superficial lesions were not identified with US; evaluation of another three was limited by shadowing. Thickness of the lesions visualized was 0.2-26.0 mm (mean, 1.9 mm +/- 2.6). Most lesions (77%) were hypoechoic, 9% were anechoic, 12% had mixed echogenicity, and 2% were isoechoic or hyperechoic. The diagnostic role of high-frequency US appears limited. It did not help differentiate benign from malignant lesions, but it did enable accurate delineation of deep margins of lesions and allowed noninvasive measurement of thickness. These features may help in the preoperative evaluation of skin tumors and in monitoring the response to therapy for certain inflammatory conditions.