P228 Mobile phone thermal imaging as an ambulatory assessment tool in Raynaud’s phenomenon
Authors: Dinsdale Graham , Nazeer Shanees , Manning Joanne , Murray Andrea , Herrick Ariane 
Published: April 2022

Abstract

Background/Aims
Raynaud’s phenomenon (RP) is episodic colour change of the skin in response to cold or emotional stress. Thermography is currently used to investigate RP in the hospital setting to differentiate primary RP (PRP) from RP secondary to systemic sclerosis (SSc), and to determine the severity of RP. However, RP attacks typically occur out in the community, and are therefore difficult to replicate or quantify within the clinic. Low-cost, portable mobile phone-based thermal imaging may offer a solution, allowing patients to capture thermal images of their hands during RP attacks whenever they occur. The aim of this study was firstly to assess feasibility of patients using mobile phone thermography, and secondly to investigate the quantitative parameters that can be extracted from thermal images captured in this way.

Methods
Patients (n = 13) with RP secondary to SSc (all female, median age [range] 58 [32-71] years, median duration [range] of RP 12 [1-43] years) were recruited into a 7-day study. Patients were each given a FLIR One thermal camera and smartphone handset. They were asked to image their hands twice daily (mornings/evenings) and, if possible, capture sequences of three images during RP attacks (‘start’, ’middle’ and ’end’, as assessed by the patient). Collected images were assessed for suitability for further analysis (whole hands, dorsal aspect only) and then manually marked-up using custom software (MATLAB) to extract temperature data from regions of interest on the distal aspects of the index, middle, ring and little fingers, and on the hand.

Results
Twelve patients (92%) completed the study (one patient lost to follow-up). Patients returned 352 images in total (range: 4-54), of which 251 were suitable for further analysis. The median [interquartile range] patient rating of the overall difficulty of using the thermal camera to image their hands/RP was 3 [4] on a scale from 1:Very Easy to 10:Very difficult. Mean [SD] non-attack temperatures (mornings and evenings grouped) were: 25.4 [0.2] °C for the digits and 28.4 [0.5] °C for the dorsum. During RP attacks mean [SD] temperatures were: 22.3 [0.1] °C for the digits and 27.4 [0.9] °C for the dorsum. Including data from only those patients who imaged RP attacks (n = 9), the within-patient temperature difference, mean [SD], (non-attack images minus RP attacks) for the digits was -3.9 [3.5] °C.

Conclusion
Mobile phone thermography is a feasible method, including as rated by patients, for collecting rich, quantitative data about RP and importantly including RP episodes outside the clinic or hospital setting. The ability to detect differences in temperature due to RP attacks may enable new, sensitive outcome measures for clinical trials in RP. Further work on the sensitivity of this method to temperature changes induced by (e.g.) the introduction of vasodilator therapy is now required.

Disclosure
G. Dinsdale: None. S. Nazeer: None. J. Manning: None. A. Murray: None. A. Herrick: None.