The accuracy of elastographic strain ratio and ultrasound thickness in the differentiation of thin and thick cutaneous melanoma.

Abstract

Cutaneous melanoma is the most deadly of skin neoplasms. Few studies have investigated the role of elastography characteristics so the ability of elastography in the differentiation of thin and thick cutaneous melanoma is still narrow. To investigate the accuracy of elastography in differentiating thin and thick melanoma, by measuring strain ratio (SR) between the lesion and adjacent dermis and hypodermis. We investigated by ultrasound and elastography 52 melanoma lesions in 49 patients. The receiver operating characteristic (ROC) curve method was used to investigate the accuracy of ultrasound and elastographic measurement of SR to surrounding tissue, in the differentiation of thin and thick melanomas. The histopathological measurement of lesions depth called Breslow index was the golden standard test. Areas under the curve (AUC) showed low accuracy for SR to hypodermis in distinguishing between thin melanomas and others (AUC = 0.739, 95% confidence interval [CI] = 0.508-0.970]) with a cut-off value of 0.950, being the only statistically significant result in matter of elastographic measurements. Highly statistically significant results were obtained for B-mode ultrasound depth measurements of the lesion, with an AUC = 0.970 (95% CI = 0.927-1.0) in discriminating thin melanomas of others and 0.951 (95% CI = 0.869-1.0) in discriminating thick melanomas of other types. Despite the appearance that SR may correlate with the depth of the lesion, elastography, by measuring the SRs to dermis and hypodermis, does not have enough accuracy in distinguishing thin and thick melanoma.