Magnetic resonance imaging in early inflammatory arthritis: what is its role?

Magnetic resonance imaging (MRI) has important applications in musculoskeletal medicine. It allows the visualization of bone and soft tissues in three dimensions using a multiplanar technique and is uniquely suited to imaging the rheumatoid joint. Bony erosions are seen well using MRI in early rheumatoid arthritis and are frequently detected before they appear on plain radiographs. Bone marrow oedema is another important MRI feature associated with inflammatory joint disease and may be a forerunner of erosion. Synovial membrane inflammation and hypertrophy are detected after contrast enhancement and also by the use of dynamic MRI techniques, which provide a non-invasive method to accurately measure the inflammatory process. This information can be analysed and collated using MRI scoring systems and ultimately may be used to improve diagnostic accuracy, predict prognosis and monitor therapy in these patients. This review examines the case for the use of MRI in early inflammatory arthritis, outlining its strengths and potential weaknesses as an imaging modality in this context and indicating its potential role in clinical practice.