Pertechnetate uptake of joints in rheumatoid arthritis

A new isotopic method for evaluation of inflammatory activity in rheumatoid arthritis is reported. By use of repeated whole body profile scanning a double tracer examination with 99mTc-pertechnetate and 113mIn-transferrin was performed. Total pertechnetate activity and total indium activity were measured over both hands, both feet, the ankles, and over the knee joints. In addition, the extravascular component of pertechnetate uptake and the ratio extravascular/total pertechnetate activity were calculated for these regions. The activity curves were followed up to 2 h after tracer injection in seven female patients presenting with rheumatoid arthritis and in six female controls. The four parameters calculated were compared and statistical analysis revealed the most significant discrimination of both groups for the ratio extravascular/total pertechnetate activity 2 h after injection (P less than 0.002).