Reliability of a novel thermal imaging system for temperature assessment of healthy feet

Background: Accurately predicting the risk of diabetic foot ulceration (DFU) could dramatically reduce the enormous burden of chronic wound management and amputation. Yet, the current prognostic models are unable to precisely predict DFU events. Typically, efforts have focused on individual factors like temperature, pressure, or shear rather than the overall foot microclimate. Methods: A systematic review was conducted by searching PubMed reports with no restrictions on start date covering the literature published until February 20, 2019 using relevant keywords, including temperature, pressure, shear, and relative humidity. We review the use of these variables as predictors of DFU, highlighting gaps in our current understanding and suggesting which specific features should be combined to develop a real-time microclimate prognostic model. Results: The current prognostic models rely either solely on contralateral temperature, pressure, or shear measurement; these parameters, however, rarely reach 50% specificity in relation to DFU. There is also considerable variation in methodological investigation, anatomical sensor configuration, and resting time prior to temperature measurements (5-20 minutes). Few studies have considered relative humidity and mean skin resistance. Conclusion: Very limited evidence supports the use of single clinical parameters in predicting the risk of DFU. We suggest that the microclimate as a whole should be considered to predict DFU more effectively and suggest nine specific features which appear to be implicated for further investigation. Technology supports real-time in-shoe data collection and wireless transmission, providing a potentially rich source of data to better predict the risk of DFU.

Section: Microclimate Predictionmentioning

confidence: 99%

Prediction of Diabetic Foot Ulceration: The Value of Using Microclimate Sensor Arrays

Jones

Bibb

Davies

et al. 2019

“…Infrared thermography (IRT) has several advantages of being noninvasive, safe, and does not require physical contact. [11][12][13][14][15] Skin temperature variations seem to be useful for identifying pathological situations especially in the diabetic foot. [16][17][18] Strong asymmetry appears to be a sign of abnormality, whereas symmetrical bilateral distribution of skin temperature is physiological.…”

Section: Introductionmentioning

confidence: 99%

Infrared Thermography Follow-Up After Lower Limb Revascularization

Ilo

Romsi

Pokela

et al. 2020

Background: The purpose of this study was with a simple clinical setting to compare skin temperature changes in the feet before and after revascularization and to identify possible correlation between ankle brachial index (ABI) and toe pressure (TP) values and foot skin temperature patient with and without diabetes. Methods: Forty outpatient clinic patients were measured ABI, TP, and the skin temperature using infrared thermography (IRT) at the foot before and after revascularization. Patients in the revascularization group were divided into subgroups depending on whether they had diabetes or not and a wound or not. Results: There were clear correlation between increase of ABI and TP and increase of the mean skin temperature on the feet after revascularization. The temperature was higher and the temperature change was greater among patients with diabetes. Side-to-side temperature difference between the revascularized feet and contralateral feet decreased after treatment. The mean temperature was higher in the feet with wound whether patient had diabetes mellitus or not. Conclusion: The simple, prompt, and noninvasive IRT procedure showed its potential as a follow-up tool among patients with diabetes or peripheral arterial disease and previous lower limb revascularization.

“…This technique is contactless and has the potential to improve usability, as it captures the entire plantar side of both feet. [3][4][5][6][7][11][12][13][14][15] Further, a computer or dedicated application can calculate thermal differences. 16 These initiatives have not yet resulted in home monitoring systems, as initial IR cameras were too expensive.…”

mentioning

confidence: 99%

Infrared 3D Thermography for Inflammation Detection in Diabetic Foot Disease: A Proof of Concept

Doremalen

Netten

Baal

et al. 2019

Background: Thermal assessment of the plantar surface of the foot using spot thermometers and thermal imaging has been proven effective in diabetic foot ulcer prevention. However, with traditional cameras this is limited to single spots or a two-dimensional (2D) view of the plantar side of foot, where only 50% of the ulcers occur. To improve ulcer detection, the view has to be extended beyond 2D. Our aim is to explore for proof of concept the combination of three-dimensional (3D) models with thermal imaging for inflammation detection in diabetic foot disease. Method: From eight participants with a current diabetic foot ulcer we simultaneously acquired a 3D foot model and three thermal infrared images using a high-resolution medical 3D imaging system aligned with three smartphone-based thermal infrared cameras. Using spatial transformations, we aimed to map thermal images onto the 3D model, to create the 3D visualizations. Expert clinicians assessed these for quality and face validity as +, +/-, -. Results: We could replace the texture maps (color definitions) of the 3D model with the thermal infrared images and created the first-ever 3D thermographs of the diabetic foot. We then converted these models to 3D PDF-files compatible with the hospital IT environment. Face validity was assessed as + in six and +/- in two cases. Conclusions: We have provided a proof of concept for the creation of clinically useful 3D thermal foot images to assess the diabetic foot skin temperature in 3D in a hospital IT environment. Future developments are expected to improve the image-processing techniques to result in easier, handheld applications and driving further research.