High-frequency ultrasound with elastography can help differentiate between cancerous and benign skin conditions, according to data reported at the Radiological Society of North America (RSNA) Annual Meeting.
“High-frequency ultrasound with elastography has the potential to improve the efficiency of skin cancer diagnosis,” said the lead author, Eliot L. Siegel, MD, Vice Chairman of the Department of Radiology at the University of Maryland School of Medicine. “It successfully delineated the extent of lesions and was able to provide measurable differentiation among a variety of benign and malignant lesions.”
“Dermatologists tend to biopsy any lesions that seem visually suspicious for disease,” coauthor Bahar Dasgeb, MD, of the Department of Dermatology at Wayne State University in Detroit and the Pinkus Dermatopathology Lab in Monroe, MI, noted in a news release. “Consequently, many benign lesions are needlessly biopsied in order to avoid the risk of missing a potentially deadly melanoma.”
Elastography was found to distinguish between benign and malignant lesions not by their visible appearance but by measuring their elasticity or stiffness. Since malignancies are stiffer than benign growths, elastography, when added to high-frequency ultrasound imaging of the skin, has potential to improve the accuracy of traditional clinical diagnosis of skin cancers and, in some cases, eliminate unnecessary biopsies of benign skin lesions, the researchers said, calling the procedure noninvasive, convenient, and inexpensive.
For the study, the researchers used an ultra high-frequency ultrasound system to image 40 patients with a variety of malignant and nonmalignant skin lesions. Malignant tumors included squamous cell carcinoma, basal cell carcinoma, and melanoma. Benign lesions included were dermatofibroma and lipoma.
The researchers calculated the ratio of elasticity between normal skin and the adjacent skin lesion, and used laboratory analysis to confirm their diagnoses. Cystic lesions, which are not malignant, demonstrated high levels of elasticity, while malignant lesions were significantly less elastic. The elasticity ratio of normal skin to the various skin lesions ranged from 0.04 to 0.3 for cystic skin lesions to above 10.0 for malignant lesions.
In addition, high-frequency ultrasound with elastography allows for accurate characterization of the extent and depth of the lesion below the surface, which can aid physicians in treatment, Dr. Siegel said.
“The visualized portion of a skin lesion can be just the tip of the iceberg, and most dermatologists operate ‘blindly’ beyond what they can see on the surface. High-frequency ultrasound provides almost microscopic resolution and enables us to get the size, shape, and extent of the lesion prior to biopsy.”