J Rheumatol. 2021 Jul 1:jrheum.210077. doi: 10.3899/jrheum.210077. Online ahead of print.
ABSTRACT
OBJECTIVE: To standardize and improve the accuracy of detection of arthritis by thermal imaging.
METHODS: Children with clinically active arthritis in the knee or ankle, as well as healthy controls, were enrolled to the development cohort and another group of children with knee symptoms were enrolled to the validation cohort. Ultrasound was performed for the arthritis subgroup for the development cohort. Joint exam by certified rheumatologists was used as a reference for the validation cohort. Infrared thermal data were analyzed using a custom software. Temperature after within-limb calibration (TAWiC) was defined as the temperature differences between joint and ipsilateral midtibia. TAWiC of knees and ankles was evaluated using ANOVA across subgroups. Optimal thresholds were determined by receiver operating characteristic (ROC) analysis using Youden index.
RESULTS: There were significant differences in mean and 95th TAWiC of knee in anterior, medial, lateral views, and of ankles in anterior view, between inflamed and uninflamed counterparts (p<0.05). The area under the curve (AUC) was higher by 36% when using TAWiCKnee than those when using absolute temperature. Within validation cohort, the sensitivity of accurate detection of arthritis in knee using both mean and 95th TAWiC from individual views or combined all 3 views ranged from 0.60 to 0.70 and the specificity was greater than 0.90 in all views.
CONCLUSION: Children with active arthritis or tenosynovitis in knees or ankles exhibited higher TAWiC than healthy joints. Our validation cohort study showed promise of the clinical utility of infrared thermal imaging for arthritis detection.
PMID:34210832 | DOI:10.3899/jrheum.210077
