[Osteoarticular scintigraphy in comparison with clinical evidence]

Bone scintigraphy is a technique which is often resorted to in diagnostic rheumatology. There are few data on the effective relevance of bone scintigraphy in the evaluation of chronic inflammatory diseases of the joints. The aim of this study was to compare the results of bone scintigraphy with clinical evidence in patients with rheumatoid arthritis or osteoarthritis. Seventy-five patients were submitted to total body bone scintigraphy (44 rheumatoid arthritis, 31 osteoarthritis). The nuclear medicine specialist indicated the list of joints showing uptake. For the same patients a rheumatologist indicated the number of affected joints. The laboratory and clinical data were recorded. The patients were first stratified according to the prevalence of the clinical evidence and scintigraphic uptake. The distribution was found to be not significant. Only 5.3% of patients showed no uptake. Thirty-three patients had no clinical evidence of disease; among these, 30 showed joint uptake. Considering only the patients with clinical evidence, 97.6% showed joint uptake. These results were confirmed even when the data were analyzed by sex, disease and therapy. Considering the patients with clinical evidence, the uptake/clinical ratio did not show any significant correlation. The number of joints with clinical evidence correlated with the erythrocyte sedimentation rate. The number of joints showing uptake correlated only with age. In conclusion, on average, scintigraphy, performed in patients with rheumatoid arthritis and osteoarthritis, highlights a significantly higher number of joints involved as compared to what would be expected on the basis of clinical evaluation. It remains to be defined whether this is an overestimation related to the characteristics of the scan or whether it is sign of a higher sensitivity in highlighting the site of inflammation. Against the latter hypothesis is the absence of correlation with the inflammatory indexes.