Abstract Background/Aims Infrared thermography is used in tertiary referral centres to help differentiate between primary and secondary Raynaud’s phenomenon (RP). Technological improvements have enabled development of lower-cost (£500), portable devices. This study aimed to compare a low-cost device to a ‘clinical’ camera (laboratory standard, £10,000) to determine whether low-cost cameras may be suitable for clinical use in non-specialist centres. Specific objectives were to assess low-cost camera measurements at baseline and following hand cold challenge and the effect of acclimatising patients prior to imaging (i.e. is temperature-control required?). Methods The low-cost camera underwent quality assurance testing, measuring a temperature standard (20oC) at room temperatures between 21-28oC. Patients undergoing routine thermal imaging for RP were recruited. Thermal imaging of hands was carried out on entering the temperature-controlled clinical vascular laboratory (unacclimatised) and following acclimatisation of 20 mins at 23oC. Patients underwent standard cold challenge (15oC, 1 minute). Low-cost (FLIR-C-3X) and clinical cameras (FLIR-A655sc) were used to image both hands simultaneously for 15 mins rewarming. Data was averaged over 8 fingers. A distal dorsal difference at baseline (DDD, temperature gradient, finger-dorsum of hand) was compared for unacclimatised versus acclimatised. Rewarming data, over 15 mins, provided the ‘area under the rewarming curve’, gradients of rewarming (2 and 15 mins) and the maximum temperature reached (both cameras). Results The low-cost camera was affected by environmental temperature (‘true’ 20 °C was measured as 18 °C at 21 °C room temperature and 22 °C at 28 °C room temperature. 45 patients with RP were recruited into the study. For 16 patients there were technical issues with the low-cost camera at baseline but rewarming was captured for all patients (Table 1). DDD was lower as measured by both cameras, post versus pre-acclimatisation, but did not reach significance (p = 0.144, p = 0.431). Rewarming outcome measures showed high convergent validity between the low-cost and clinical cameras (ρ = 0.983 (p 0.001)). Conclusion The low-cost camera was susceptible to environmental conditions indicating that caution is required in interpretation of data when used in non temperature-controlled conditions. Acclimatisation requires further research. However, the excellent convergent validity between cameras indicates that low-cost imaging still warrants further investigation. Disclosure J. Pietras: None. M. Mandzuk: None. J. Manning: None. G. Dinsdale: None. S. Wilkinson: None. P. New: None. M. Samaranayaka: None. M. Hughes: None. M. Dickinson: None. A. Herrick: None. A. Murray: None.
Pietras et al. (Wed,) studied this question.