Ultrasound in the evaluation of the inflammatory myopathies.

The lack of precise measures of disease activity may complicate the care of patients with inflammatory myopathies (IM). Techniques currently available to physicians in practice rely on measurement of function, strength, laboratory indices, muscle biopsy, and imaging techniques. Although MRI has become the method of choice to assess IM, it is expensive, difficult for some patients to tolerate, and contraindicated in those with pacemakers, aneurysm clips, and other ferromagnetic biomedical implants. Ultrasonography is an alternative approach to image the muscular system. Newer applications of ultrasound, such as power Doppler sonography (PDS), contrast-enhanced ultrasound, and sonoelastography, show some promising results in further characterizing normal and pathologic states. Technical improvements, including extended field-of-view, compound imaging, and harmonic imaging, further enhance one's ability to display changes in muscle morphology. This article reviews the sonographic appearances of normal and pathologic muscle with respect to inflammatory myopathies.