Sonographic Analysis of Abscess Maturation in a Porcine Model

Abscesses are walled-off collections of infected fluids that often develop as complications in the setting of surgery and trauma. Abscess care depends on size, location, composition and complexity, among other patient factors. The goal of this work is to describe, using the latest ultrasound imaging technologies, the progression of abscess development in a porcine animal model. Intramuscular or subcutaneous injections of bacteria plus dextran particles as an irritant led to identifiable abscesses over a 2- to 3-week period. The abscesses were imaged at least weekly with B-mode, 3D B-mode, shear-wave elastography (SWE) and color flow imaging. Mature abscesses were characterized by a well-defined core of varying echogenicity surrounded by a hypoechoic capsule that was highly vascularized on Doppler imaging. Size and shape changes during development were quantified with 3D imaging. With SWE, the lesion stiffness varied interiorly and generally decreased over time. These ultrasound features potentially provide biomarkers to facilitate improved selection of treatment strategies for abscesses.