Since the development of high-frequency transducers in the 1980s, physicians and ultrasonographers have been utilizing musculoskeletal ultrasound to provide detailed imaging of anatomic structures. Today, many practitioners are incorporating musculoskeletal ultrasound as a useful tool to help evaluate and treat their patients. As the popularity of musculoskeletal ultrasound continues to increase, a better understanding of its capabilities will be required.
This chapter surveys essential knowledge about musculoskeletal ultrasound, including the indications for its use; advantages and disadvantages of this technique over other imaging modalities; and the basic physics of ultrasound. The appearance of normal musculoskeletal tissues is reviewed and illustrated using numerous images of normal and pathologic structures evaluated through diagnostic musculoskeletal ultrasound examination.
After obtaining a detailed history and performing a comprehensive physical examination, the physician may determine that further diagnostic workup is required to identify the source of a patient’s dysfunction. A musculoskeletal ultrasound examination can provide high-resolution scans of various anatomic structures, including tendons, ligaments, nerves, joint capsules and muscles. Consequently ultrasound can be used to diagnose tendon pathology, muscle injury, ligament damage, and joint effusions. In addition, ultrasound can be utilized to evaluate other structures throughout the musculoskeletal system while helping to guide interventional procedures in real time.
Currently a vast array of modalities is available that can provide imaging of the human body. Musculoskeletal ultrasound offers certain advantages over other forms of imaging such as radiography, computed tomography (CT), and magnetic resonance imaging (MRI).
Ultrasound can be used to provide real-time, high-resolution images that require no preparation aside from body positioning. Unlike MRI or CT, ultrasound can be utilized to provide a dynamic and interactive examination. Apart from its ability to provide static imaging, ultrasound allows the physician to investigate a patient’s dynamic complaints such as “snapping” or “popping,” which can be evaluated while performing provocative maneuvers.
In addition, in response to patient feedback, the ultrasound beam can be targeted over involved areas of tenderness, which may help correlate patient symptoms with abnormalities identified on the ultrasound scan. In comparison, MRI and CT may identify many abnormalities that have no clinical relevance to the patient’s symptoms. Furthermore, utilizing diagnostic musculoskeletal ultrasound, structures can be compared with the contralateral limb. Musculoskeletal ultrasound images of many soft tissues typically have greater resolution than those provided by MRI or CT.
Musculoskeletal ultrasound is also relatively safe and inexpensive to use on children, individuals with pacemakers, and pregnant women, since it emits no radiation and lacks a high-powered magnet. In addition, in comparison with CT, MRI, and radiography, ultrasound units can be portable, allowing utilization outside a hospital or radiology suite. Finally, because ultrasound can identify structures such as vessels and nerves, it can be used to safely and accurately guide musculoskeletal interventional procedures.