When and how should we use imaging in individuals at risk of rheumatoid arthritis?

Figures

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  FIGURE 1. US sub-clinical synovitis and tenosynovitis in ACPA+ individuals with MSK symptoms. Gray scale (A) and power Doppler (A’) positive synovitis of the 3rd MCP joint in a patient at-risk of RA high titre positive anti-CCP antibodies and non-specific musculoskeletal symptoms. Similar US findings are shown in the 2nd PIP joint in a different at-risk individual (B,B’) with positive anti-CCP antibodies and rheumatoid factor, hands arthralgia. (C,C’) Illustrate tenosynovitis of the 2nd extensor tendon compartment in a third individual at-risk of RA with high titre anti-CCP antibodies and clinically suspect arthralgia. All images were obtained using a longitudinal approach. Asterisks indicate synovial hypertrophy.

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  FIGURE 2. US bone erosion (not detected by x-rays) in the 5th MTP joint in an individual with high titre ACPA and non-specific MSK symptoms. (A) Longitudinal US scan of the lateral aspect of the 5th MTP joint. The white arrow indicates the presence of bone erosion. (B) Correspondent feet x-rays showing no bone erosions in the 5th metatarsophalangeal joint. This patient presented with non-specific musculoskeletal symptoms and high titre anti-CCP antibodies.

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  FIGURE 3. MRI and US sub-clinical synovitis in a patient with CSA and high titre ACPA. MRI (A) synovitis (white arrows) of the 3rd PIP joint in an individual at-risk of RA with corresponding gray-scale (B) and power Doppler (B’) US scans. This individual had clinically suspect arthralgia and positive anti-CCP antibodies (high titre) and rheumatoid factor. These images were obtained 6 weeks before progression to RA. Asterisk indicates synovial hypertrophy, while the arrowhead a small joint effusion.

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  FIGURE 4. A suggested algorithm to guide the use of MRI, US and radiography in individuals at risk of RA without clinical synovitis based on current evidence. In patients that do not have any symptoms there is no evidence to suggest that any imaging techniques are of diagnostic or predictive value. For Palindromic rheumatism extracapsular inflammation can be captured on imaging during flare episodes and if subclinical inflammation is seen in the asymptomatic phase the diagnosis of palindromic rheumatism should be re-considered. For anti-citrullinated protein antibody (ACPA) negative individuals with inflammatory symptoms i.e., clinically suspect arthralgia (CSA) and ACPA+ individuals an ultrasound should be performed. If the ultrasound is negative MRI may be able to detect subtle sub-clinical inflammation, particularly in extracapsular structures. For at risk individuals such as first-degree relatives with non-inflammatory musculoskeletal (MSK) symptoms radiographs should be performed to look for alterative diagnoses.