Can optical spectral transmission assess ultrasound-detected synovitis in hand osteoarthritis?

Development of an Ultrasound Imaging Atlas for Grading Osteoarthritis in the First Metatarsophalangeal Joint

OBJECTIVE

Ultrasound (US) imaging may play a fundamental role in the earlier detection and assessment of first metatarsophalangeal joint (MTPJ) osteoarthritis (OA) because of its ability to depict tissue-specific morphologic changes before the point of irreversible structural damage. However, the role of US in supporting the diagnosis of OA in foot joints has not been clearly defined. The aims of this study were to develop a semiquantitative US atlas (the AUT ultrasound imaging [AUTUSI] atlas) to grade the degree of osteoarthritic change in the first MTPJ and to evaluate the intraexaminer and interexaminer reproducibility of using the atlas.

METHODS

US images were obtained from 57 participants (30 participants with radiographically confirmed first MTPJ OA). The AUTUSI atlas supports the examination of grading joint effusion, synovial hypertrophy, synovitis, osteophytes, joint space narrowing, and cartilage thickness. Six examiners used the atlas to independently grade 24 US images across 2 sessions. Intraexaminer and interexaminer reproducibility were determined using percentage agreement and Gwet's AC2.

RESULTS

Observations using the AUTUSI atlas demonstrated almost perfect-to-perfect interexaminer agreement (percentage agreement ranged from 96% to 100%, and Gwet's AC2 values ranged from 0.81 to 1.00) and moderate-to-perfect intraexaminer agreement (percentage agreement ranged from 67% to 100%, and Gwet's AC2 values ranged from 0.54 to 1.00).

CONCLUSION

The AUTUSI atlas demonstrated excellent intraexaminer and interexaminer reproducibility for evaluating first MTPJ joint effusion, synovial hypertrophy, synovitis, joint space narrowing, osteophytes, and cartilage thickness. The AUTUSI atlas affords an opportunity to detect prognostic markers of OA earlier in the disease cascade and has the potential to advance understanding of the pathologic process of first MTPJ OA.

Optical imaging compared to clinical examination in 484 rheumatoid arthritis patients: the Leeuwarden Handscan Registry

The Handscan is a novel objective optical imaging device for disease follow-up and management in rheumatoid arthritis patients. We aim to examine the association between the baseline outcomes of the Handscan, disease activity levels and joint swelling. The Handscan measures differences in laser light absorption between joints of fingers and wrists and adjacent reference tissue, indicating the presence or absence of inflammation. The device gives an optical spectral transmission (OST) index per joint. The average of these indices is represented in the total optical score (TOS). Associations between TOS and DAS28 at subject level and OST and swelling at joint level were examined. 484 RA patients were included. Compared to patients with high disease activity (defined by DAS28), TOS was significantly lower in patients with moderate (estimated coefficient B: - 7.09, P < 0.001), low disease activity (B: - 6.99, P < 0.001) and patients in remission (B: - 7.72, P < 0.001) but could not distinguish between the latter three disease states. TOS was significantly lower in females (B: - 3.2, P < 0.001). OST was significantly higher in swollen than non-swollen joints (B: 0.28, P < 0.001). TOS was significantly higher in patients with high disease activity than in those in remission or with low and moderate disease activity. The difference in TOS between males and females should be accounted for in the interpretation of this outcome. The OST at joint level discriminates swollen from non-swollen joints and could be a more promising tool than the overall optical activity reflected in TOS.