Rheumatoid arthritis (RA) is a disease with a large economic impact due to the long lasting disabling nature of the disease. Furthermore, diagnosis of the disease is difficult and only a scheme with different symptoms is used to diagnose rheumatoid arthritis, often only by probability.

Due to the fact that effective disease modifying pharmacological treatment is available and should be started early in established cases of RA, in combination with the adverse effect potential of these substances (e.g. methotrexate), a fast reliable diagnostic tool to diagnose rheumatoid arthritis would be highly appreciated by the medical community and the patients. Furthermore, for invasive treatments (surgery, puncture), an imaging method to display the activity pattern in different joints would be a major advantage.

For the evaluation of the effectiveness of pharmacological therapy in rheumatoid arthritis, up to now, radiological measurements of the destruction process of the joints are used. This method has the disadvantage that it is time consuming insofar as changes in the radiological images must occur. It allows only an evaluation if the joints are destructed (which should be excluded by the new therapy regimen). Again, a quantifiable method for the determination of the effects of new therapeutic approaches would be highly appreciated.