[Preoperative sonographic diagnosis of melanoma--comparison of 7.5- and 20-MHz sonography]

Abstract

Aim: High-frequency sonography has become extremely helpful for the preoperative assessment of malignant melanoma. The purpose of this study was to compare the preoperative vertical tumour thickness as assessed by 7.5 MHz as well as 20 MHz ultrasound probes to the postoperative tumour thickness as determined histomorphometrically.

Methods: 249 patients with malignant melanoma were studied using a conventional 7.5 MHz ultrasound machine (since 1987) or a high-frequency 20 MHz ultrasound imaging system (since 1991).

Results: The correspondence of the sonographically assessed tumour thickness with the thickness assessed by histomorphometry was significantly better for high-frequency sonography (r = 0.94) as compared to conventional sonography (r = 0.76). For stages pT3 and pT4, however, this difference was not significant.

Conclusion: Based on these data, high-frequency sonography should be given preference in the preoperative assessment of malignant melanoma over conventional 7.5 MHz ultrasound. However, for stages pT3 and pT4 both methods offer similarly reliable results.