Inflammatory myopathies: issues in diagnosis and management.

The techniques of magnetic resonance imaging and spectroscopy have been shown to have utility in the diagnosis and management of inflammatory muscle diseases. But perhaps more important have been the new insights into the pathophysiology of these diseases which MR studies, along with new immunologic data on autoantibodies and cellular infiltrates, have afforded. Pathologic subsets of inflammatory muscle disorders have been identified, suggesting, for example, that PM and DM are distinct disorders, thereby challenging the idea that these are relatively homogeneous syndromes. Further insights into disease pathogenesis which are likely to emerge from these new findings may allow identification of etiologic factors and improved approaches to treatment.