Skeletal muscle imaging and inflammatory myopathies.
PURPOSE OF REVIEW: A variety of modalities exist for the imaging of skeletal muscle including radiography, ultrasound, computed tomography, and MRI. This article highlights the utility of these modalities in evaluating skeletal muscle diseases. Newer techniques such as T2 mapping, blood oxygenation level dependent imaging, diffusion tensor imaging, and magnetic resonance spectroscopy are also explored. RECENT FINDINGS: Cross-sectional imaging including computed tomography and magnetic resonance is the current standard in skeletal muscle imaging. The advantages of these modalities include the ability to image in different planes and to evaluate the distribution of disease and disease burden. Newer magnetic resonance-based techniques also provide functional information in addition to anatomic information. Radiography and ultrasound have a more limited role and are mainly used to detect calcifications and evaluate the texture of skeletal muscle. SUMMARY: Magnetic resonance is a useful modality for evaluating skeletal muscle and allows for the assessment of disease burden. It can elucidate potential targets for biopsy. Newer magnetic resonance techniques can acquire functional information in addition to anatomic information and hold tremendous potential for detecting, characterizing, and monitoring treatment for inflammatory myopathies.