[Early diagnosis of chronic polyarthritis with conventional roentgen imaging]

Radiographs used to be the gold standard of imaging techniques in rheumatoid arthritis. New imaging techniques allow more detailed examinations of soft tissue changes, the predominant features of early RA. This could change the place of radiography especially in this phase of the disease. The best available radiographic technique is necessary to capture the changes of early RA. Radiographs of both hands and feet are needed for early diagnosis and standardized follow-up. Extent and distribution of indirect signs of arthritis (soft tissue swelling and juxtaarticular osteoporosis) vary with disease activity but can provide important information also for the differential diagnoses. Inter-reader reliability of these changes is low, thus, questioning the validity of these findings. Direct signs of arthritis (erosions and joint space narrowing) are more easy to detect and are used for the quantification of the long-term disease course, in clinical studies, as proof for the disease modifying property of an intervention. Direct signs of arthritis are also found in other diseases, so they are not exclusive signs of RA. Nevertheless a typical radiographic finding in early RA is highly specific and is the most important risk factor for a poor prognosis. Therefore, it serves as the basis for therapeutic decisions, e.g., for an early aggressive treatment. As long as there are no data that the findings with the new imaging techniques are as relevant for prognosis, radiographs cannot be replaced in early RA.