Potential of indium-111 to measure inflammatory arthritis

Since an objective noninvasive method for measuring inflammation in arthritis is lacking, radioimaging experiments were conducted with 111indium-chloride (111InCl3) in the collagen model. A computer imaging index, reflecting uptake in the feet and ankles, was significantly greater in 16 rats immunized with collagen than in 6 nonimmunized rats (mean +/- SEM 1.18 +/- 0.04 vs 0.39 +/- 0.02, for the 2 groups, respectively, p less than 0.001). Additional analyses provided evidence that the 111InCl3 technique can be used to measure objectively progression of the arthritic response of rats of immunization with collagen, and pilot comparisons with conventional bone scintigraphy in 2 patients with rheumatoid arthritis suggested that the method is applicable to human arthritic disease.