Endocrine Abstracts

Thyroid Eye Disease (TED) is an autoimmune inflammatory condition of the orbit occurring in the setting of thyroid disease. Prevention of the distressing physical and psychological sequelae of TED depends on accurate quantification of disease activity to allow selection of the most appropriate treatment modality. Current practice is based on the use of a Clinical Activity Score (CAS). As an alternative approach, and with the potential benefits of reproducibility and ease of use, we have examined the utility of orbital infra-red thermography in quantifying TED inflammatory activity. Patients were imaged with eyes open and closed. Open-eye images were analysed with a temperature profile along the corneal centres line of intersection. This profile showed, per eye, two main peaks (infra-red emission from the conjunctiva overlying the medial (MR) and lateral (LR) recti insertions) and one trough (infra-red emission from the cornea (CA)). Closed-eye images were described with the maximum temperature in the periorbital region (Tmax) and the rate of eyelid heating following localised cooling by fan (ΔE). In an ethically approved study of 49 age- and sex-matched subjects (active TED n=15; inactive TED n=9; normal control n=25) we found (1) lateral:medial rectus insertion temperature ratios (LR-CA)/(MR-CA) correlate significantly with TED patient status (P=0.0002, 2-tailed Student’s t-test); (2) there is a trend toward greater Tmax and ΔE values in active versus inactive TED; (3) Tmax correlates significantly with the classical CAS in inactive/active TED patients (Pearson’s R=0.433, P=0.034). In conclusion we describe the use of orbital thermography as an imaging modality in the clinical assessment of TED. Our experiments describe methods to obtain thermography-derived parameters useful in the investigation of ocular/orbital pathology and we show these to compare favourably with the current methods of TED disease assessment. Further experiments to ascertain the predictive value of thermography in TED are planned.