Thermography of rheumatoid arthritis and osteoarthritis

Thermography is a noninvasive, nondestructive method of scanning that does not require physical contact between measuring device (camera) and scanned object. Inflammation of peripheral joints, close to skin surface, is the dominant type of presentation of rheumatoid arthritis, a systemic immunological disease. Due to that, those joints are suitable for infrared thermal scanning. Considering the changes of the bones in the affected joints, as a control group, apart from healthy subjects, study was conducted on patients with osteoarthritis as well. This paper investigated thermographic images of both hands of healthy subjects, patients with rheumatoid arthritis and patients with osteoarthritis. On thermal images obtained, temperature of certain regions was analyzed. Basic statistical analyses (minimum, maximum, standard deviation, mean, and variance) were performed. It was concluded that heat distribution over the skin surface during an immunological inflammatory reaction depends on the affected joint and on the intensity of the disease and given drug therapy. There is a statistically significant difference in finger and metacarpophalangeal joint mean temperature values on ventral and dorsal sides for both healthy patients and patients with rheumatoid arthritis and osteoarthritis. Also, there is a statistically significant difference of mean temperature values between the aforementioned patient groups, making the use of thermography a possible method of differentiating normal subjects and rheumatoid arthritis subjects and osteoarthritis subjects from each other.