Optical Imaging Visualizes Inflammation in Osteoarthritis

Both ultrasound and fluorescence optical imaging (FOI) can detect inflammation in hand joints of rheumatoid arthritis and osteoarthritis patients, according to the first study using FOI for the examination of potential inflammation in osteoarthritis. The findings, published online Aug. 26 in the Annals of the Rheumatic Diseases, underscore those of previous studies that inflammation plays an important role in the disease course of osteoarthritis. Currently, osteoarthritis is not considered to be a primary inflammatory joint disease, although activated joints often lead to flares and correlate with joint pain. Using ultrasound, clinicians can visualize joint changes in osteoarthritis, including bone abnormalities (osteophytes, erosions and cartilage damage), synovial and periarticular inflammation. This can help affirm their diagnosis and inform them about the patient’s inflammatory status when they make their treatment decision.[[{"type":"media","view_mode":"media_crop","fid":"41777","attributes":{"alt":"©Praisaeng/Shutterstock.com","class":"media-image media-image-right","id":"media_crop_4053757870569","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"4442","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"font-size: 13.008px; line-height: 1.538em; float: right;","title":"","typeof":"foaf:Image"}}]] Similarly, indocyanine green (ICG)-based fluorescence optical imaging  has been shown to be capable of detecting inflammatory changes in human arthritic joints in good agreement with clinical examination by magnetic imaging resonance and ultrasound, wrote the researchers, who were led by Sarah Ohrndorf, MD, of Charité Universitätsmedizin in Berlin.  They compared the amount and distribution of inflammatory signs in wrist and finger joints of the clinically dominant hand in patients with osteoarthritis and rheumatoid arthritis by fluorescence optical imaging and gray-scale ultrasound and power Doppler ultrasound. The researchers performed fluorescence optical imaging and ultrasound in 1,170 joints in 90 patients, including 67 rheumatoid arthritis patients and 23 osteoarthritis patients. Joint inflammation was graded by a semi-quantitative score for each imaging method. The results show that ultrasound revealed wrist and metacarpophalangeal joints were mostly affected in rheumatoid arthritis. Distal interphalangeal joints were graded higher in osteoarthritis. In fluorescence optical imaging, rheumatoid arthritis and osteoarthritis featured inflammatory changes in the respective joint groups depending on the phase of fluorescence dye flooding. “Considering FOI results, inflammatory changes can be visualized in patients with rheumatoid arthritis and also clearly in patients with osteoarthritis,” the researchers wrote. Also, they noted that this confirmation of the inflammatory component in the pathogenesis of hand osteoarthritis goes along with recent ultrasound studies that show synovitis and activity can predict radiographic progression of hand osteoarthritis. The believe that “an inflammatory component in the course of osteoarthritis should not be underestimated,” and that the clinical use of FOI in patients with osteoarthritis could help clinicians to visualize inflammation, make therapeutic decisions and lead to follow-up investigations.  

References:

Glimm AM, Werner SG, et al.

Analysis of distribution and severity of inflammation in patients with osteoarthitis compared to rheumatoid arthritis by ICG-enhanced fluorescence optical imaging and musculoskeletal ultrasound: a pilot study.

Annals of the Rheumatic Diseases

. Published online Aug. 26, 2015.(http://dx.doi.org/10.1136/annrheumdis-2015-207345).