Diagnostic radiography in rheumatoid arthritis: benefits and limitations

In the light of more modern techniques such as sonography and magnetic resonance imaging, the reader may well ask if plain radiography has still a role in the diagnostic work-up of rheumatoid arthritis. However, in daily routine, the value of diagnostic radiography in support of the clinical and laboratory diagnosis of rheumatoid arthritis is unrivaled. It allows differentiation from other joint diseases, such as osteoarthritis or crystal arthropathies, when the ARA criteria are not conclusive for the diagnosis of rheumatoid arthritis. Further, plain radiography is part of the basic documentation of the disease in measuring disease progression. Therapeutic decisions, such as systemic versus local therapy, and selection of drugs, as well as the form of local therapy, are heavily dependent on radiographs. However, the limitations of radiography in evaluating disease progression have to be recognized. Ultrasonography, as a 'bedside method', and MRI are indispensable adjuncts to radiography, because they are superior in detecting synovitis, early forms of cartilage damage as well as bone reaction such as erosions and cysts. A superior assessment of the degree of synovial changes is also possible with MRI.