Use of contrast-enhanced ultrasonography in musculoskeletal medicine

Ultrasound contrast agents enhance blood flow signals and allow assessment of microcirculation. The objective of this review is to systematically identify and summarize the literature on the use of contrast-enhanced ultrasonography in the musculoskeletal field. A literature search was conducted using the following keywords: ultrasound, contrast agent, and relevant musculoskeletal terms (muscle, tendon, joint, or bone). Only articles devoted to human research were reviewed. Information about each study, including category, subject, site, type of contrast agent, imaging technique, and contribution, was summarized. We reviewed 44 of the 260 retrieved articles. The associated categories were muscle (21 articles), tendon (4 articles), joint (17 articles), and bone (2 articles). Contrast-enhanced ultrasonography has been widely applied to the clinical evaluation of rheumatoid arthritis (n = 12) and research of muscle perfusion (n = 20). SonoVue (n = 20) was the most commonly used contrast agent, followed by Levovist (n = 17), Definity (n = 6), and Sonazoid (n = 1). Gray scale sonography (n = 3), color Doppler sonography (n = 4), power Doppler sonography (n = 15), and nonlinear imaging techniques specific for the existence of microbubbles (n = 22) were used according to different protocols. Contrast-enhanced ultrasonography has emerged as a promising diagnostic and research tool in musculoskeletal systems. Its application in bony structures is limited, owing to poor ultrasound penetration; however, development of nonlinear imaging techniques may promote advanced research on microcirculation in tendons.