[Soft tissue manifestations of early rheumatic disease: imaging with MRI]

The aim of this study was to evaluate typical magnetic resonance imaging (MRI) findings in early rheumatic diseases manifesting at the soft tissues of the hand using a retrospective analysis.

A total of 186 MRI examinations of patients with clinical suspicion of a rheumatic disease were evaluated in a consensus reading by two experienced radiologists. All imaging patterns were assessed with respect to their type and localization. Under blinded and non-blinded conditions diagnoses were correlated with final clinical diagnosis.

The most frequent diagnoses were rheumatoid arthritis (RA, 45.7%) and psoriatic arthritis (PsA, 15.6%). The mean correlation between clinical and MRI diagnosis (r) was 0.75 in blinded and 0.853 in non-blinded reading (p <0.001). The following extra-articular imaging patterns were found: synovitis (59.1%), tendovaginitis (91.4%), dactylitis (14.5%), and bone marrow edema (18.3%). Only dactylitis was specific for a particular rheumatic disease (PsA; r=0.934; sensitivity 84.9%, specificity 82.4%).

Inflammatory conditions of the hand can be reliably detected with MRI. In many cases the definite diagnosis can only be made when taking clinical, serological, and radiographic results into account (+13.7% increase of significance).