Positron emission tomography with C-11-D-deprenyl in patients with rheumatoid arthritis - Evaluation of knee joint inflammation before and after intra-articular glucocorticoid treatment

Seven patients with arthritic disease and with clinical signs of inflammation of the knee joint, were investigated with positron emission tomography (PET) after injection of [N-methyl-C-11]-D-deprenyl Two healthy volunteers were included as controls. In five patients the investigation was repeated after an intra-articular injection of glucocorticoids. All patients showed very high uptake of the tracer in the paraarticular structures of the joint. After treatment there was approximately a 50% reduction of the uptake in the treated knees, both in the high uptake regions and in the surrounding soft tissues. No change was observed in the non-treated knees. In the healthy volunteers, only soft tissue surrounding the joint showed an uptake of the tracer, but at a magnitude which was 6-8 times lower than the high uptake regions in the arthritis patients. Although the mechanisms for the high uptake of C-11-D-deprenyl in affected joints of patients with arthritis is not clear, the present work points to a potential of PET for the assessment of disease intensity and monitoring of treatment.