Use of smartphone attached mobile thermography assessing subclinical inflammation: a pilot study.

OBJECTIVE

To verify the reliability and validity of FLIR ONE, a device connected to a smartphone, for the assessment of inflammation based on relative temperature increase compared with the thermography routinely used in pressure ulcer (PU) and diabetic foot assessment.

METHOD

Participants in this pilot cross-sectional observational study were recruited from the patients in the PU team rounds and the diabetic foot outpatient clinic at the university hospital in January 2015. Cohen's kappa coefficient with its 95% confidence intervals was used to evaluate the criterion-related validity and inter- and intra-rater reliability for the thermal imaging assessment. For assessing criterion-related validity, a hand-held high-end infrared thermography device was used to provide reference data. Comparison of thermal images between the smartphone-connected device and the hand-held device was performed with both a 'predetermined range' and an 'automatically-set range.' For assessing inter-rater reliability, two assessors evaluated the thermal images taken by the mobile thermography. For assessing intra-rater reliability, one assessor evaluated the thermal images twice. The thermal images were shown to the assessors at random.

RESULTS

Among 16 thermal images obtained from eight patients, kappa coefficients for each value were as follows: for the predetermined range and automatically-set range, respectively, the criterion-related validity was 1.00 (95% confidence interval 1.00-1.00) and 1.00 (95% confidence interval 1.00-1.00); the inter-rater reliability was 1.00 (95% confidence interval 1.00-1.00) and 1.00 (95% confidence interval 1.00-1.00); and the intra-rater reliability was 1.00 (95% confidence interval 1.00-1.00) and 1.00 (95% confidence interval 1.00-1.00).

CONCLUSION

This pilot study suggests that FLIR ONE can work as an alternative device for assessing subclinical inflammation in PUs and the diabetic foot in clinical settings. Our results may facilitate clinicians in accepting the routine use of thermal imaging assessment at the patients' bedside.