What is the role of Ultrasound in the diagnosis of musculoskeletal infection?
In general, musculoskeletal US is an important adjunct to the other modalities. US excels in the evaluation of superficial soft tissues, and benefits from higher spatial resolution than MRI, higher soft tissue contrast than CT, and a lack of ionizing radiation. However, US suffers from poor penetration into deeper structures and is therefore best utilized to evaluate superficial tissues. Additionally, US is optimized for answering a specific clinical question, rather than for the survey of larger anatomic areas such as can be performed with radiography, CT, or MRI.
In the specific diagnosis of infection, musculoskeletal US can be used to identify fluid collections, particularly pockets of potentially drainable pus in the midst of an extensive cellulitis. US also excels in the identification of nonradiopaque foreign bodies that may act as a nidus for infection.