Clinical issue: Inflammatory muscle diseases are quite heterogeneous and frequently a specific diagnosis is not easy.
Standard radiological methods: Magnetic resonance imaging (MRI) is best suited to demonstrate pattern and size of inflamed muscles.
Performance: Sensitivity of MRI in showing inflamed muscles is nearly 100%. Specificity, however, is much lower.
Practical recommendations: In cases of suspected bacterial myositis, sonography may be used to exclude abscess formation prior to MRI for more precise information about inflamed muscles.
Keywords: Abscess; Magnetic resonance imaging; Myositis; Myositis ossificans; Sarcoidosis.