Diagnostic ultrasound ( PDFDrive )

CHAPTER
23
Overview of Musculoskeletal
Ultrasound Techniques and
Applications
Colm McMahon and Corrie Yablon
SUMMARY OF KEY POINTS
• A wide variety of inlammatory, degenerative, traumatic,
and neoplastic conditions can be imaged accurately and
cost-effectively with ultrasound.
• Understanding optimal imaging techniques and recognizing
and avoiding common artifacts is essential to
musculoskeletal ultrasound.
• Ultrasound can provide higher-resolution imaging of nerves
and tendons compared with standard clinical magnetic
resonance imaging examinations.
• Dynamic imaging may be performed with ultrasound,
which can assist in the diagnosis of tendon and
ligamentous injury.
CHAPTER OUTLINE
GENERAL CONSIDERATIONS
Doppler Imaging
Elastography
Extended Field of View Imaging
MUSCLES
TENDONS
LIGAMENTS
NERVES
JOINT ASSESSMENT
SOFT TISSUE MASSES
FOREIGN BODIES
SOFT TISSUE INFECTION
CONCLUSION
GENERAL CONSIDERATIONS
Ultrasound is becoming a central part of the diagnostic pathway
for patients with musculoskeletal complaints. In many cases,
ultrasound is performed as an alternative or complement to
magnetic resonance imaging (MRI). Ultrasound has several
advantages over MRI that have been described in the literature,
succinctly by Nazarian in a 2008 perspective article. 1 Ultrasound
is well tolerated by patients and can be performed in those with
contraindications to MRI, such as implanted cardiac devices or
other MRI-incompatible implants, large size, or claustrophobia.
Ultrasound examinations oten take less time to perform than
the corresponding MRI examinations. Ultrasound provides
higher-resolution imaging of tendons and ligaments than routine
musculoskeletal MRI. Ultrasound also provides the ability to
image dynamically, which can be important in the diagnosis
of disorders of impingement and subluxation of nerves or
tendons. It is excellent at determining the fundamental tissue
characterization of solid versus cystic in the setting of a mass
lesion—this type of characterization may otherwise require the
administration of intravenous contrast when MRI is used to
distinguish a T2-hyperintense solid mass from a simple cyst.
In many cases, patients can be given results at the time of their
examination.
As a general rule, a systematic approach to musculoskeletal
ultrasound examination of the joints using deined protocols is
preferred to a focal examination when time permits. Focused
imaging of symptomatic areas of concern adds additional
diagnostic information to the routine protocol. 2 When evaluating
a foreign body or palpable sot tissue mass, focal assessment can
be performed, with attention to the relationship to nearby
anatomic structures, critical to treatment planning. As with MRI
interpretation, it is imperative that the radiologist have a clear
understanding of musculoskeletal anatomy before performing
or interpreting a sonographic examination, especially when
previous studies are not available for comparison.
High-frequency linear ultrasound probes (12-15 MHz) are
recommended for musculoskeletal imaging. Higher-frequency
probes (15-17 MHz) can be helpful for evaluating supericial
anatomy, for example, ligaments and tendons in the ingers.
Hockey stick–style high-frequency probes can be very useful
for evaluation of ine structures, providing focused small ield
of view images and permitting good skin contact in the peripheral
extremities. Lower-frequency (3-9 MHz) linear probes may be
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