Thermal imaging has been applied to detect possible temperature variations in various rheumatic disorders. This study sought to determine whether rheumatoid arthritis (RA) patients without active synovitis in their hands exhibit different baseline thermographic patterns of the fingers and palms when compared to healthy individuals. Data from 31 RA patients were compared to that of 51 healthy controls. The RA patients were recruited upon confirmed absence of synovitis by clinical examination and musculoskeletal ultrasound. Participants underwent medical infrared imaging of the regions of interest (ROIs). Significant differences were found between the mean temperatures of the palm regions (29.37 °C (SD2.2); n = 306) and fingers (27.16 °C (SD3.2); n = 510) of the healthy participants when compared to the palm regions (31.4(SD1.84)°C; n = 186) and fingers (30.22 °C (SD2.4); n = 299) of their RA counterparts (p = 0.001), with the latter group exhibiting higher temperatures in all ROIs. Logistic regression models confirm that both palm and finger temperature increase significantly in RA without active inflammation. These innovative findings provide evidence that baseline thermal data in RA differs significantly from healthy individuals. Thermal imaging may have the potential to become an adjunct assessment method of disease activity in patients with RA.

Objectives Studies have shown conflicting characteristic thermographic patterns of the feet in patients with active rheumatoid arthritis (RA). However, to date no studies have compared thermographic patterns of patients with RA in remission and healthy controls. Thus this study aimed to investigate whether the thermal characteristics of the feet of RA patients, in clinical and radiological remission differ to those of healthy controls. Methods Using convenience sampling, RA patients were recruited upon confirmed absence of synovitis by clinical examination and musculoskeletal ultrasound. Thermal images of the feet were taken. Each foot was subdivided into medial, central, lateral, forefoot and heel regions. Subsequently, temperatures in the different regions were analyzed and compared to a cohort of healthy adults. Results Data from 32 RA patients were compared to that of 51 healthy controls. The Independent samples T-Test demonstrated a significant difference in temperatures in all the regions of the forefoot between RA participants versus healthy subjects (Table 1). Using the One-Way ANOVA test, no significant difference was found between all the forefoot regions (p = 0.189) of RA patients. Independent sample T-test found significant differences in all heel regions between the two groups (Table 2). One-Way ANOVA demonstrated no significant differences (p = 0.983) between the different foot regions (n = 192) of RA patients. Conclusion These findings suggest that RA patients in clinical and radiological remission exhibit significantly different feet thermographic patterns compared to healthy controls. This data will provide the basis for future studies to assess whether thermographic patterns change with disease activity.

BackgroundThermography has been utilised in a number of studies in rheumatoid arthritis (RA),1 however there is a paucity of evidence as regards to the possibility of applying this non-invasive technology to the detection of synovitis of the hands and wrists. With normative data having been already published,2 it is now possible to compare the thermographic characteristics of RA patients without active synovitis to those with a normal thermal distribution in order to determine the baseline characteristics of RA hands and wrists. This would consequently provide a foundation against which further studies investigating RA patients with synovitis can be compared.ObjectivesTo determine whether rheumatoid arthritis (RA) patients without active synovitis in their hands exhibit different baseline thermographic patterns of the fingers and palms when compared to healthy individualsMethodsData from 31 RA patients were compared to 51 healthy controls. Inclusion criteria were confirmed absence of synovitis by clinical examination and musculoskeletal ultrasound in rheumatoid patients. Thermographic imaging of the regions of interest (ROIs) were obtained as per established protocols2 ResultsSignificant differences were found between the mean temperatures of the palm regions and fingers of the healthy participants when compared to the palm regions and fingers of their RA counterparts (p=0.001), with the latter group exhibiting higher temperatures in all ROIs. No significant differences were found between ROIs of the palms and fingers of both hands in either group. Logistic regression models confirm that both palm and finger temperature increase significantly in RAConclusionsRA patients without active inflammation of the hands demonstrate a significantly higher mean temperature compared to healthy individuals. These findings provide evidence that baseline thermal data in RA differs significantly from healthy individuals. Thermal imaging may have the potential to become an adjunct assessment method of disease activity in patients with RA.References[1] Frize M, Adéa C, Payeur P, Di Primio G, Karsh J, Ogungbemile A. Detection of rheumatoid arthritis using infrared imaging. In: Dawant BM, Haynor DR, eds. 2011.[2] Gatt A, Formosa C, Cassar K, et al. Thermographic patterns of the upper and lower limbs: Baseline data. Int J Vasc Med. 2015.Disclosure of InterestNone declared

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