[Digital 20 MHz sonography of basalioma in the B-scan].

Digital 20 MHz b-scan sonography is a new non-invasive tool in dermatological routine diagnostics. The 20-MHz linear scanner employed in this study has a signal penetration of 7 mm, a lateral resolution of 200 microns and an axial resolution of 80 microns. Seventy-five basal cell carcinomas were examined by ultrasound. An exact correlation of histological slides and sonographic images allowed us to explain the sonographic phenomena of basal cell carcinoma (BC). BCs exhibit a well-defined area with poor echoes; they sometimes even show a total loss of reflection. In the tumor parenchyma inhomogenously distributed internal echos were found. Below the tumor post-tumoral enhancement of the signal reflection is common (depending on the type of BC -up to 70%). Our results prove that digital 20 MHz ultrasonic imaging systems are well suited for studying the extension, thickness and tissue texture of basal cell carcinoma.