Use of ultrasound elastography for skin and subcutaneous abscesses.

OBJECTIVE: Elastography is a new adjunct to real-time ultrasound imaging that overlays traditional B-mode imaging with a color graphic representation of tissue elasticity. Soft tissue infections are common presenting conditions in the emergency department, and elastography has the potential to help in diagnosis and treatment of evolving soft tissue infections as they progress from induration to fluctuant abscesses, but to our knowledge, no studies of elastography in superficial soft tissue have been published. We hypothesized that elastography would provide increased information regarding skin abscesses.
METHODS: This was a prospective study of patients with suspected skin abscesses requiring surgical drainage in the emergency department of an urban tertiary care center. Abscesses were imaged with B-mode imaging and elastography in orthogonal planes. Ultrasound images were analyzed for characteristics of the elastographic images.
RESULTS: A total of 50 patients with suspected skin abscesses underwent B-mode imaging and elastography. Elastography accurately differentiated the induration surrounding the abscess from the surrounding healthy tissue, a differentiation that was not visible on B-mode imaging. The elastographic properties of the abscess cavity were variable and not always seen, even with purulence identified during incision and drainage. In some cases, elastography identified abscess cavities not seen on B-mode imaging. When seen, the abscess cavity could be characterized by elastographic color and speckle patterns.
CONCLUSIONS: Elastography identified the tissue induration and some abscess cavities not seen on B-mode imaging. It offers a way to characterize abscesses that may be useful clinically, but more research is needed.