Generalized skeletal response to 99mtechnetium methylene diphosphonate in rheumatoid arthritis

The total body retention (TBR) and the 5- and 24-h lumbar spine to soft tissue (LS/ST) ratios of 99mtechnetium methylene diphosphonate was studied in 19 patients with rheumatoid arthritis (RA), 16 patients with metastatic tumors that did not involve the lumbar spine, 10 patients with chronic renal failure and 17 controls. The TBR was significantly higher in all groups compared to the controls. The 5-h LS/ST did not differ between any of the groups although the 24-h LS/ST ratios were significantly elevated in RA and those with chronic renal failure. The 24-h LS/ST in RA was correlated only with disease duration. The results are consistent with a generalized increase in bone turnover in RA and may explain the recognized lack of sensitivity of quantitative scintigraphic techniques in this disorder.