A review of thermal methods and technologies for diabetic foot assessment

Abstract

Temperature analysis has been considered as a complementary method in medical evaluation and diagnosis. Several studies demonstrated that monitoring the temperature variations of the feet of diabetic patients can be helpful in the early identification of diabetic foot manifestations, and also in changing behaviors, which may contribute to reducing its incidence. In this review, several and most used techniques for assessing the temperature of the feet are presented, along with original published work on specific applications in diabetic foot complications. A review of solutions and equipment that operate according to the temperature assessment techniques is also presented. Finally, a comparison between the various technologies is presented, and the authors share their perspective on what will be the state of affairs in 5 years.

Keywords:

• diabetic foot
• diagnosis
• infrared thermography
• liquid crystals thermography
• self-management
• temperature monitoring
• ulcer prevention

Acknowledgements

This work was supported by COMPETE – Sistema de Incentivos à Investigação e Desenvolvimento Tecnológico, Projectos de I&DT Empresas em co-promoção, under QREN TICE. Healthy (FCOMP-01-0202-FEDER-013842).

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• International diabetes federation predicts an increase of the number of diabetic patients up to 591.9 million by the year 2035 (an increase of 55.0%).

• It is estimated that 2–10% persons with diabetes may develop foot ulceration during the disease course that would be the precursor to approximately 85% of lower extremity amputations.

• The increase of foot temperature is an early warning for foot complications in diabetes, and occurs at a reversible stage of the disease.

• Monitoring the temperature variations of the foot can be helpful in the early identification of diabetic foot manifestations and also in changing behaviors that contribute to reducing its incidence.

• It was found that an at-home monitoring of foot temperature may reduce the incidence of foot ulcers by >60%.

• The prevention of serious foot complications has a potential to reduce costs related to amputations and in-hospital care.

• Many of the available technologies for foot temperature monitoring are based on thermal imaging, liquid crystals thermography and may be used either for at-home care or for screening in hospital care.

• Liquid crystals thermography has limitations in terms of image resolution and pressure sensitivity; but it allows a rapid temperature imaging, even though the thermographs may sometimes be difficult to interpret.

• The traditional infrared cameras enable remote and non-contact mapping of thermal patterns of the feet, which prevents unwanted pressures and the transmission of pathological organisms; additionally, it is capable of measuring other angles of the foot.