Sonographic Features of Abscess Maturation in a Porcine Model

• Published in: Ultrasound in medicine & biology Vol. 47; no. 7; pp. 1920 - 1930
• Main Authors: Leotta, Daniel F., Bruce, Matthew, Wang, Yak-Nam, Kucewicz, John, Khokhlova, Tatiana, Chan, Keith, Monsky, Wayne, Matula, Thomas J.
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01-07-2021
• Subjects: Abscess; Curvature; Doppler imaging; Plane-wave Doppler; Shear-wave elastography; Three-dimensional; Ultrasound; Doppler imaging; Three-dimensional; Shear-wave elastography; Abscess; Plane-wave Doppler; Ultrasound; Curvature
• ISSN: 0301-5629; 1879-291X
• DOI: 10.1016/j.ultrasmedbio.2021.03.011

Abscesses are walled-off collections of infected fluids that often develop as complications in the setting of surgery and trauma. Treatment is usually limited to percutaneous catheterization with a course of antibiotics. As an alternative to current treatment strategies, a histotripsy approach was developed and tested in a novel porcine animal model. The goal of this article is to use advanced ultrasound imaging modes to extract sonographic features associated with the progression of abscess development in a porcine model. Intramuscular or subcutaneous injections of a bi-microbial bacteria mixture plus dextran particles as an irritant led to identifiable abscesses over a 2 to 3 wk period. Selected abscesses were imaged at least weekly with B-mode, 3-D B-mode, shear-wave elastography and plane-wave Doppler 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. 3-D imaging demonstrated the natural history of abscess morphology, with the abscess becoming less complex in shape and increasing in volume. Furthermore, shear-wave elastography demonstrated variations in stiffness as phlegmon becomes abscess and then liquefies, over time. These ultrasound features potentially provide biomarkers to aid in selection of treatment strategies for abscesses.