Obligatory medical device diagnostics.
- Radiographs of affected joints (method of choice); not appropriate in the early phase of the disease; radiographic signs include:
- Symmetrical, often polyarticular involvement.
- Concentric joint space extension
- Erosions due to bone destruction (destruction of bone tissue).
- Secondary arthroses
- Ankyloses (stiffening of joints)
- Subchondral cysts
- Ulnar deviation/deformities of the fingers (swan neck/buttonhole deformity).
Optional medical device diagnostics – depending on the results of the history, physical examination, laboratory diagnostics and obligatory medical device diagnostics – for differential diagnostic clarification or to exclude complications.
- Arthrosonography (ultrasound examination of joints) – suitable for early diagnosis of synovitis (inflammation of the synovial membrane); signs may include:
- Joint effusion
- Pannus
- Baker’s cysts
- Ruptures of tendons
[Note: Grade 1 capsular detachments (common ultrasound finding) are not yet indicative of rheumatoid arthritis].
- Magnetic resonance imaging (MRI; computer-assisted cross-sectional imaging (using magnetic fields, that is, without X-rays); particularly well suited to visualize soft tissue lesions) of the affected joints; this method shows changes earlier than the X-rays; signs of rheumatoid arthritis are (in addition to those mentioned in the X-rays).
- Synovialitis/preerosive changes.
- Joint scintigraphy provides an overview of the pattern of involvement and may provide clues if radiographic findings are negative
- Capillaroscopy (microscopic examination of nailfold capillaries) – to differentiate between rheumatoid arthritis (RA) and psoriatic arthritis (PsA) [PsA patients have more tortuous capillaries with lower capillary density compared to RA patients].
- Dual-energy computed tomography (DECT); radiologic technique that uses two energetically different X-ray tubes and special image processing to show characteristic imaging properties of uric acid depots – for detection of uric acid deposits
