Investigation of the metabolic acitivity of bone in rheumatoid arthritis.

Uptake of 99mTc pyrophosphate was measured in the midthird of the radius, ulna femur and metacarpal bones of 22 men with rheumatoid arthritis and 18 control subjects. It was significantly elevated in the rheumatoid population. In a parallel study, the retention of 99mTc methylene diphosphonate was significantly increased in 12 of these rheumatoid patients compared to 6 of the control subjects. These results suggest that there is increased bone turnover occurring in "nonjoint" bone in patients with RA and that the use of such bone as a reference standard for joint imaging is likely to prove misleading.