Raynaud’s Phenomenon Differentiating After Cold Stress Using Thermal Parameters from Fingers

The objective of this study was to determine parameters that better describe thermal models to separate people who present Raynaud’s phenomenon (RP) from those who do not. A descriptive exploratory study was conducted with 284 participants (primary RP = 14; secondary RP = 12; without diagnosis = 258) aged between 18 and 60 years, in the city of Curitiba, Brazil. A thermal camera (Fluke Ti400) was used to photograph skin temperature following a cold stress protocol. The hands were then immersed up to the carpal level in a container with water at 10 °C for 60 s. Images from both hands in six different moments were taken: (a) pre-stress to cold; (b) immediately after the cold related stress and every 5 min, until 20 min post-immersion. In order to find the best parameters to identify primary and secondary Raynaud, several features based on the temperature dissimilarities between fingers and hands were evaluated. Our results show that the dorsal-distal difference temperature (DDD) is well-known to separate individuals who do not have RP. However, primary and secondary Raynaud mix up, so no pattern can be possibly distinguished. In addition, the best result on the classification was achieved using the maximum temperature difference at 20 min and the maximum absolute temperature difference between hands at 15 min, reaching an accuracy of 80.56% ± 17.35%.