Joint microwave radiometry for inflammatory arthritis assessment

Area of Science:

• Rheumatology
• Medical Imaging
• Biomarkers

Background:

• Increased joint temperature may indicate inflammation, even without clinical signs.
• Microwave radiometry (MWR) is a rapid, non-invasive method for measuring in-depth joint temperature.

Purpose of the Study:

• To evaluate the utility of MWR for assessing patients with rheumatoid arthritis (RA) and spondyloarthritis.
• To determine if MWR can detect subclinical and overt joint inflammation.

Main Methods:

• Two independent patient-control cohorts (n=243) underwent clinical examination, joint ultrasound/MRI, and MWR.
• MWR performance was assessed against ultrasound and MRI references.
• A thermo-score was developed using MWR data from multiple joints.

Main Results:

• MWR demonstrated high sensitivity and specificity for detecting synovitis and power Doppler positivity in RA knees, outperforming clinical examination.
• A thermo-score correlated strongly with ultrasound-defined inflammation and DAS28, and improved significantly with treatment.
• MWR of sacroiliac joints differentiated spondyloarthritis patients with and without sacroiliitis.

Conclusions:

• Increased MWR-derived joint temperature reflects both subclinical and clinically evident inflammation.
• MWR shows potential as a valuable biomarker for arthritis assessment and monitoring.