Multimodal PA/US imaging in Rheumatoid Arthritis: Enhanced correlation with clinical scores

Area of Science:

• Rheumatology
• Medical Imaging
• Biomedical Engineering

Background:

• Accurate assessment of Rheumatoid Arthritis (RA) disease activity is challenging.
• Multimodal photoacoustic/ultrasound (PA/US) joint imaging visualizes microvascularization and oxygenation in RA-affected joints.
• Limited large-scale studies hinder correlation of joint oxygenation with RA disease activity.

Purpose of the Study:

• To explore the correlation between multimodal PA/US imaging scores and RA disease activity.
• To assess the clinical applicability of PA/US imaging in managing RA.

Main Methods:

• 111 RA patients underwent PA/US imaging of seven small joints.
• PA and power Doppler ultrasound (PDUS) signals were semi-quantitatively assessed (0-3 grading).
• Cumulative PA and PDUS scores (PA-sum, PDUS-sum) and relative oxygen saturation (So2) patterns were calculated and correlated with disease activity indices.

Main Results:

• PA-sum scores strongly correlated with DAS28 [ESR], DAS28 [CRP], CDAI, and SDAI (p < 0.001).
• Correlations for PA-sum scores surpassed those of PDUS-sum scores.
• Higher PA-sum scores were associated with significant differences in ESR and SJC28, and higher clinical scores in the hypoxia group.

Conclusions:

• Multimodal PA/US imaging shows potential for advancing RA assessment, particularly So2 evaluation.
• PA/US imaging offers insights into synovial tissue oxygenation and disease activity.
• Further multi-center studies with larger sample sizes are warranted to validate findings.