[High resolution 20 MHz ultrasound diagnosis in dermatology for noninvasive imaging of malignant melanomas]

For years, high-resolution b-scan ultrasound is a well established technique in dermatology regarding the preoperative determination of thickness of skin tumors like malignant melanoma or basal cell carcinoma. Most tumors appear as echopoor areas in high-frequency sonography. Until today, a differentiation between skin tumors by means of high-frequency ultrasound is not possible. This is also true concerning the differentiation between the tumor tissue itself and its subtumoral inflammatory infiltration. Therefore, this lack of differentiation leads to the fact that sonometric thicknesses of tumors often exceed the originally measured tumor thickness in histology. By means of three-dimensional reconstruction of serial b-scan images, it is possible to determine each tumor's volume and surface as well as the topographical arrangement of echopoor areas and sonographical structures. Besides high-frequency ultrasound, additional non-invasive techniques like MRI, ultrasound- or laser-doppler, computer-aided image analysis and epiluminescence microscopy are also available for diagnosing malignant melanoma. Epiluminescence microscopy is used today as a standard technique in the diagnosis of malignant melanoma due to the possibility of differential diagnosis. Latest techniques like OCT (optical coherence tomography) are not ready yet to be applied regularly in diagnosis of tumors in the field of dermatology.