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The reliability of an Achilles tendon infrared image analysis method

Herrington, LC; Oliver, Ben; Munro, A; Gerald, SM


Ben Oliver

A Munro

SM Gerald


INTRODUCTION: Prior to utilising smartphone-based thermal imaging for clinical assessment of the Achilles tendon, the intra-rater and inter-rater reliability of the method of analysis must be established, with associated standard error of measurement (SEM) and minimal detectable change (MDC) values.

METHOD: A convenience sample of 7 participants (4male, 3female, age 18.57± 1.57 years, height 173.7 ± 6.3cm, weight 73.8 ± 8.1kg) were recruited for the study, for a total of 28 skin temperature (TSk) measurements per camera. Measure- ments were taken using two infrared cameras, one handheld (FLIR E8) and one smartphone-compatible (FLIR ONE), from 0.5m and 1m distances. Regions of interest (ROI) were retrospectively selected using a freeform software ROI tool.

RESULTS: The method used to analyse TSk of the midportion of the Achilles tendon demonstrated excellent intra-rater reliability at both 0.5m and 1m distances using the FLIR ONE (ICC = 0.99, ICC = 0.99) and FLIR E8 (ICC = 0.98, ICC = 0.95). There was excellent inter-rater reliability of the method at 0.5m and good inter-rater reliability at 1m with data cap- tured from the FLIR ONE (ICC = 0.97, ICC = 0.79), and excellent ICC's at both distances for the FLIR E8 (ICC = 0.97, ICC = 0.99).

CONCLUSIONS: The method of TSk analysis using the FLIR ONE is acceptable at 0.5m and 1m distances, however data capture is recommended for the closer distance.


Herrington, L., Oliver, B., Munro, A., & Gerald, S. (2019). The reliability of an Achilles tendon infrared image analysis method. Thermology international, 29(4), 136-145

Journal Article Type Article
Acceptance Date Nov 7, 2019
Publication Date Nov 1, 2019
Deposit Date Dec 12, 2019
Journal Thermology International
Print ISSN 1560-604X
Volume 29
Issue 4
Pages 136-145
Publisher URL