Measurement Of Systemic Inflammatory Activity In Rheumatoid Arthritis By The99mTc Method

From the Department of Medicine, and the Isotope Laboratory, Central Hospital, Jyväskylä, FinlandA radioisotope method consisting of measurements of 99mTc accumulation above a large joint area was used to study systemic inflammatory activity of rheumatoid arthritis. The results were expressed as an activity index using the heart and urinary bladder as reference points. The Tc index was significantly higher in the rheumatoid arthritis patients than in the controls but there was a marked overlapping in cases with slight disease activity. The Tc index was significantly correlated with ESR, fatigue, duration of morning stiffness, grip strength and Lansbury's systemic index. No correlation was found with haemoglobin, acetylsalicylic acid requirement, Waaler-Rose titre or duration of disease. The Tc index was used with success to demonstrate the change in joint inflammation during short-term administration of oral prednisolone. The test was also used in a double-blind trial of an anthranilic acid derivative, tolfenamic acid. No effect could be shown. The effect of prolonged gold-salt treatment was reflected in the Tc index. We conclude that the Tc index can be used as an objective measure of rheumatoid disease activity. The measurement is based on increased blood supply and enhanced transport of 99mTc to the inflamed synovium.Read at the VII European Rheumatology Congress at Brighton, England, in June, 1971.