DISTINCTIVE RADIOLOGICAL FEATURES OF SMALL HAND JOINTS IN RHEUMATOID-ARTHRITIS AND SERONEGATIVE SPONDYLOARTHRITIS DEMONSTRATED BY CONTRAST-ENHANCED (GD-DTPA) MAGNETIC-RESONANCE-IMAGING

A series of patients with clinically early inflammatory joint disease due to rheumatoid arthritis, psoriatic arthritis and Reiter's syndrome were examined by plain film radiography and magnetic resonance imag ( MRI), The spin echo T1-weighted precontrast, T2-weighted, and, especia lly, T1-weighted postcontrast images demonstrated distinct differences in the distribution of inflamatory changes, both within and adjacent to involved small hand joints. Two major subtypes of inflammatory arth ritis were shown, thus providing a specific differential diagnosis bet ween rheumatoid arthritis and some patients with seronegative spondylo arthritis. In particular, all the patients with Reiter's syndrome who were studied, and half of those with psoriatic arthritis, had a distin ctive pattern of extra-articular disease involvement, The need for a n ew classification of clinical subsets in psoriatic arthritis has been recently suggested. The present findings suggest that magnetic resonan ce imaging could be useful in such a reclassification of seronegative spondyloarthritis, as well as offering considerable potential for a re appraisal of pathogenesis and therapy. In this series, it was also not ed that juxta-articular osteoporosis on plain film did not correlate w ith bone marrow oedema on MRT. Hence the aetiology of this common radi ographic finding also merits further consideration.