Synovitis in patients with early inflammatory arthritis monitored with quantitative analysis of dynamic contrast-enhanced optical imaging and MR imaging.

PURPOSE: To evaluate quantitative perfusion measurements of dynamic indocyanine green (ICG)-enhanced optical imaging for monitoring synovitis in the hands of patients with inflammatory arthritis compared with dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging and clinical outcome. MATERIALS AND METHODS: This study was approved by the ethics committee at the institution. Individual joints (n = 840) in the hands and wrists of 28 patients (14 women; mean age, 53.3 years) with inflammatory arthritis were examined at three different time points: before start of therapy and 12 and 24 weeks after start of therapy or therapy escalation. Treatment response was assessed by using clinical measures (simple disease activity index [SDAI]), ICG-enhanced optical imaging, and DCE MR imaging. Dynamic images were obtained for optical imaging and DCE MR imaging. The rate of early enhancement (REE) of the perfusion curves of each joint was calculated by using in-house developed software. Correlation coefficients were estimated to evaluate the associations of changes of imaging parameters and SDAI change. RESULTS: Quantitative perfusion measurements with optical imaging and MR imaging correctly identified patients who responded (n = 18) and did not respond to therapy (n = 10), as determined by SDAI. The difference of REE after 24 weeks of treatment compared with baseline in responders was significantly reduced in optical imaging and MR imaging (optical imaging: mean, -21.5%; MR imaging: mean, -41.0%; P < .001 for both), while in nonresponders it was increased (optical imaging: mean, 10.8%; P = .075; MR imaging: mean, 8.7%; P = .03). The REE of optical imaging significantly correlated with MR imaging (ρ = 0.80; P < .001) and SDAI (ρ = 0.61; P < .001). CONCLUSION: Quantitative analysis of contrast-enhanced optical imaging allows for potential therapeutic monitoring of synovitis in patients with inflammatory arthritis.

Detection of synovitis in the hands of patients with rheumatologic disorders: diagnostic performance of optical imaging in comparison with magnetic resonance imaging.

OBJECTIVE: To prospectively compare an indocyanine green (ICG)-enhanced optical imaging system with contrast-enhanced magnetic resonance imaging (MRI) for the detection of synovitis in the hands of patients with rheumatologic disorders. METHODS: Forty-five patients (30 women [67%], mean ± SD age 52.6 ± 13.4 years) in whom there was a clinical suspicion of an inflammatory arthropathy were examined with a commercially available device for ICG-enhanced optical imaging as well as by contrast-enhanced 3T MRI as the standard of reference. Three independent readers graded the degree of synovitis in the carpal, metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints of both hands (1,350 joints), using a 4-point ordinate scale (0 = no synovitis, 1 = mild, 2 = moderate, 3 = severe). Statistical analyses were performed using a logistic generalized estimating equation approach. Agreement of optical imaging ratings made by the different readers was estimated with a weighted kappa coefficient. RESULTS: When MRI was used as the standard of reference, optical imaging showed a sensitivity of 39.6% (95% confidence interval [95% CI] 31.1-48.7%), a specificity of 85.2% (95% CI 79.5-89.5%), and accuracy of 67.0% (95% CI 61.4-72.1%) for the detection of synovitis in patients with arthritis. Diagnostic accuracy was especially limited in the setting of mild synovitis, while it was substantially better in patients with severely inflamed joints. Moderate interreader and intrareader agreement was observed. CONCLUSION: The evaluated ICG-enhanced optical imaging system showed limitations for the detection of inflamed joints of the hand in comparison with MRI.