1. In a series of thirteen patients with rheumatoid arthritis and eleven control subjects clearance rates of 133 Xe and 99m Tc from the knee joint were monitored before and after oral administration of the anion-transport inhibitor potassium perchlorate. 2. The clearance rate of 99m Tc was reduced following perchlorate administration although there was no change in the 133 Xe clearance rate. This suggests the presence of a perchlorate-blockable anion-transport mechanism across the synoviocyte.
1. Uptake of intravenously administered radioactive technetium ( 99m Tc) was measured over the knee joints in normal human volunteers, in patients with osteoarthritis and in groups of synovectomized and unoperated patients with rheumatoid arthritis. The uptake was compared with clinical indices of inflammation (pain, tenderness swelling and stiffness), and the clearance rate of intra-articularly injected radioactive xenon ( 133 Xe). The 99m Tc uptakes were found to be unrelated to the isotope dose and the day-to-day reproducibility was acceptable. 2. The mean uptake of 99m Tc was within normal limits in osteoarthritis. Both in synovectomized and in unoperated rheumatoid arthritis 99m Tc uptake was significantly higher than in normal subjects. 3. Of the clinical indices studied significant correlation of 99m Tc uptake was found with pain and swelling in all groups of patients studied. 4. Faster clearance of 133 Xe in unoperated rheumatoid arthritis correlated well with the higher 99m Tc uptakes. 5. The results confirm that 99m Tc uptakes are raised in inflammatory arthritis but not in degenerative arthritis. The relation of 99m Tc uptake to the clinical indices of inflammation and to the 133 Xe clearance from the joint is discussed.