Benefits of thermal imaging in orbital inflammation disorders

Assessing periocular inflammation is essential in several disorders, including Thyroid Eye Disease (TED). The Clinical Activity Score (CAS) is the most commonly used method to assess orbital inflammation, but is associated with significant inter-observer variability. The aim of this study was to assess the ability of Infrared Thermography (IRT) to detect orbital inflammation in TED and other orbital inflammation disorders (OOID).

A retrospective study was conducted between March 2020 and November 2023. Patients were divided into four groups: active TED (CAS ≥ 3), non-active TED (CAS < 3), OOID, and healthy controls. Demographics, proptosis, and CAS were recorded. IRT was performed in 6 periocular areas, including the caruncle. Four IRT periocular patterns were characterized.

Hundred and ten patients (63.64% of women) with a mean age of 59.47 (25-93) years were included. Thirteen (11.82%) patients were included in the active TED group, 44 (40.00%) in the non-active TED group, 17 (15.45%) in the OOID group and 36 (32.73%) in the control group. Non-active TED and control patients had lower mean caruncular and periocular temperatures compared to active TED and OOID patients (p < 0.05). The caruncular temperature was significantly higher in active TED patients compared to OOID patients (p < 0.05). Non-active TED and control patients mainly showed round and upper coma IRT patterns while active TED and OOID patients showed crab claw and other IRT patterns (p < 0.05).

Periocular IRT measurement is a rapid, simple, non-invasive, cost-effective, and reproducible method for detecting orbital inflammation and allows differentiating active TED from OOID.