Quantified ultrasound elastography in the assessment of cutaneous carcinoma

To evaluate the feasibility of high-frequency ultrasound and ultrasound elastography (USE) in discriminating benign from malignant skin lesions in a prospective cohort study and to introduce the use of a "strain ratio" for evaluation of skin lesions.

A commercial ultrasound system with a 14-MHz transducer was used to visualize skin lesions requiring biopsy on clinical evaluation. Anatomic ultrasound and USE imaging of the skin lesions was performed using 2- to 4-mm gel stand-off pads. A region of interest was manually selected over the area of each lesion with the lowest strain. The concept of a strain ratio of the compressibility of the normal skin at the corresponding layer to that of the least compressible region of a lesion in question was created and applied. This ratio was subsequently correlated with blind histopathological evaluation for malignancy.

55 patients were included in the study with a total of 67 lesions evaluated. 29 lesions were malignant and 38 benign. All malignant lesions had strain ratios ≥3.9. All benign lesions had strain ratios ≤3.0. A diagnostic value between 3.0 and 3.9 would result in 100% sensitivity and specificity in the characterization of these lesions as malignant.

This pilot study demonstrated that USE plus strain ratio appears to be a promising modality in providing diagnostic determination between cancerous and benign primary solitary skin lesions prior to biopsy.

This is the first reported study applying an original mathematical elastographic ratio, or strain ratio, to evaluate primary solitary skin lesions.