The early stage of rheumatoid arthritis (RA) is primarily manifested in the soft tissue of the hand. Although ultrasound (US) is regarded as an important imaging process in diagnostic medicine, precise characterization of sonomorphological changes has not yet been undertaken.
20 patients with RA were examined with US. Two radiologists described semiquantitatively the characteristics of synovial changes in the hand in a consensus-based process and measured the synovial width. Statistical methods were used to determine whether the various synovial changes differed significantly and to identify the most frequent locations of changes.
On the basis of the significant differences in morphology and synovial width, it is possible to distinguish between unremarkable findings, pannus tissue and band-like synovitis. Pannus tissue is most frequently found on the finger flexor tendons (FFT), the metacarpophalangeal joints (MCP) and the tendon of M. extensor carpi ulnaris (ECU). Band-like synovitis exhibits an uncharacteristic distribution pattern with a slight propensity to favour these locations.
The FFT, MCP joints and ECU tendons are particularly important in systematic US screening of the hand for the purpose of establishing reliable evidence of inflammatory changes. Different stages of RA can be identified on the basis of the characteristic types of synovitis and the number of joints and tendons affected.