Value of 99mTc-IgG scintigraphy in the prediction of joint destruction in patients with rheumatoid arthritis of recent onset.

The ability of technetium-99m-labelled polyclonal human immunoglobulin G (99mTc-IgG) scintigraphy to predict joint destruction in patients with rheumatoid arthritis (RA) was investigated in this study. The progression of radiographically determined joint destruction in wrists, hands and feet was compared with the results of physical and laboratory examination, as well as 99mTc-IgG scintigraphy, measured at the beginning of a year-long study on 30 patients with RA of recent onset. The sensitivity of joint swelling in predicting the progression of radiographically determined joint destruction ranged between 57% and 74%. The sensitivity of 99mTc-IgG scintigraphy ranged between 71% and 100%. The specificity and positive predictive value both of joint swelling and 99mTc-IgG scintigraphy were low. Multiple regression analysis showed that for the total joint score, and for the metacarpophalangeal and forefeet joints, progression of radiographically determined joint destruction was primarily predicted by 99mTc-IgG scintigraphy. Joint swelling, ESR and IgM rheumatoid factor did not contribute to this prediction. We concluded that 99mTc-IgG scintigraphy is superior to conventional clinical and laboratory measurements in RA with respect to prediction of joint destruction.