To evaluate retrospectively the discriminatory value of bone scintigraphy, especially spot images of the hands, in differentiating early stage systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).
Data from 19 patients with SLE (3 men, 16 women) and 20 patients with RA (6 men, 14 women), presenting with early stage articular disease (arbitrarily defined as articular complaints for no longer than 3 mo), were reviewed. At this stage, radiographs were normal in all patients. In all 39 patients, total body bone scintigraphy with spot images of the hands was performed as part of a complete diagnostic investigation. For differentiation between SLE and RA in early disease stage, less extensive semiquantitative description in 3 categories (normal, diffuse mildly increased, and (multi)focal moderately to markedly increased tracer accumulation) proved to be sufficient. Locations of bone scintigraphic findings were correlated to clinical findings.
In RA, bone scintigraphy revealed foci of moderate to markedly increased tracer accumulation, corresponding to the sites of clinical synovitis in all patients. In 10 patients with SLE, bone scintigraphy images of the hands were normal, and in 9 patients diffuse mildly increased tracer accumulation was observed.
The data suggest bone scintigraphy may be useful to differentiate SLE from RA in early stage disease.