Thermal imaging has the potential to become an important method to detect Rheumatoid Arthritis, according to a study published on Monday.
Rheumatoid arthritis (RA) is a long-term, progressive, and disabling disease, which causes inflammation, swelling, and pain in and around the joints and other body organs.
The study, published in the journal Scientific Reports, confirms that both palm and finger temperature increase significantly in patients with RA, said researchers at the University of Malta.
In the study carried on 82 participants, RA patients were examined by two rheumatologists.
A subset of these participants underwent diagnostic ultrasonography by a trained rheumatologist in order to ensure that the recruited participants had no active signs of synovitis in their hands and wrists.
"We used Flir T630 therma camera and followed the guidelines of the American Thermology Association," said Alfred Gatt, from the University of Malta.
The study shows that the two probability curves intersect at 31.5 for palm temperatures, the researchers said.
The results indicate that individuals whose palm temperature is less than 31.5 per cent are more likely to be healthy; while those whose palm temperature is less than 31.5 are more likely to have RA.
"Similarly, for finger temperatures, the two probability curves intersect at 30.3 per cent," Gatt said in a statement.
While ultrasonography had not detected any significant changes in the study population, thermography flagged a possible ongoing disease process by reporting these higher temperatures, the researchers said.
"We hypothesise that this temperature difference may be attributed to underlying subclinical disease activity or else that the original inflammatory process may cause irreversible thermal changes that persist after the disease activity has resolved. We will need further studies to substantiate this," said Gatt.
The researchers noted that thermal imaging is an emerging technology within medicine and has the potential to become an important clinical tool as disease processes can vary the magnitude and pattern of emitted heat in a person with RA.
"This is the first study to explore thermographic patterns of patients with Rheumatoid Arthritis comparing them to healthy controls," said Associate Professor Cynthia Formosa, also from the University of Malta and Visiting Fellow at Staffordshire University in the UK.
"Our results have clearly shown that an RA hand without active synovitis -- the medical term for inflammation of the synovial membrane -- exhibits higher temperatures when compared to healthy individuals," Formosa said.