SUBCLINICAL JOINT INVOLVEMENT IN PSORIASIS - MAGNETIC-RESONANCE-IMAGING AND X-RAY FINDINGS

Previous studies have shown that magnetic resonance imaging is more se nsitive in assessing soft tissue and bone involvement in inflammatory arthritis than conventional radiography. Therefore the main objects of this study were to evaluate the frequency of hand involvement in psor iatic patients free from arthritic symptoms, and to compare the result s with those of a healthy control population (age- and sex-matched). T wenty-five patients suffering from active nummular and/or plaque psori asis with no arthritic signs or symptoms were studied together with 12 healthy control subjects. The articular structures of both hands in a ll patients were screened using both traditional radiological techniqu es and magnetic resonance imaging. Specifically, we examined: soft tis sue swelling, periarticular effusion, joint effusion-synovial pannus, tendon sheath effusion, bone erosion, luxation, sub-luxation, bone cys ts and subchondral signal intensity abnormalities. Sixty-eight percent of our psoriatic patients were found to be positive with at least one arthritic sign using magnetic resonance imaging, while with the stand ard S-ray procedure, only 32% of the same group of patients were found to be positive. Specifically, abnormal signal intensity in the subcho ndral focal areas were seen in 9 patients using the magnetic resonance imaging technique, while in the control group, no significant abnorma lities were detected, A high percentage of psoriatic patients without apparent arthritic signs and symptoms were shown to have hand articula r involvement, in particular in the distension of the capsular and per iarticular oedema when examined with magnetic resonance imaging. In ou r experience, the use of magnetic resonance imaging allows a clear and adequate evaluation of the cartilage, bone and soft tissue material, and is diagnostically superior to S-ray in demonstrating clinically si lent and radiologically invisible articular lesions. Moreover, the sub chondral changes detected by magnetic resonance imaging mere unexpecte d findings which could imply an ischaemic origin.