A point of care thermographic camera can record 86,400 temperatures measurements across the human body nine times per second and present the data in real-time on a screen. But how do we transform the data that has always been right in front of us on the human body from information to clinical insight?
THERE IS NOTHING like a global crisis to rapidly advance our understanding. You likely have seen the deployment of thermographic systems during the COVID pandemic in the attempt to spot fever as an indicator of COVID positivity. Now 18 months into the pandemic, we have learned a lot about what works and what doesn’t, and the FDA has been quick to send warning letters when systems have been poorly configured.
The agency has stated that “when used correctly, thermal imaging systems generally have been shown to accurately measure someone’s surface skin temperature without being physically close to the person being evaluated.”
The agency continued, “Temperature-based screening, such as thermal imaging, is not effective at determining if someone definitively has COVID-19, because, among other things, a person with COVID-19 may not have a fever. A diagnostic test must be performed to determine if someone has COVID-19.”
A really important insight from the Pandemic on temperature detection is that the testing site with the best representation of internal body temperature (elevated by fever) is not the forehead (how many times have you had your forehead scanned during the pandemic?) but the inner canthus of the eye.
Indeed, in a small pilot study, researchers at the University of South Denmark1 have demonstrated the potential for temperature differences between the body core (measured by inner canthus) and the periphery (measured by ear lobe and fingertip) to provide prognostic value for 30-day mortality. Furthermore, higher-powered studies will be required to confirm this signal for use in the detection of infectious-related conditions in the emergency department.
Researchers at the Cardiovascular Institute of the South in Houma, LA are commencing work on the potential to use the data in a thermographic image to provide insight into the diagnosis and treatment of venous conditions.
The first study the team will be conducting studies to characterize the temperature difference between refluxing blood at the skin surface compared to surrounding tissue. It is hoped that this pilot study will elucidate the physiological processes that underlie the conclusions of studies at the Medical University of Silesia, Poland that show that the combination of thermographic and visual imagery is promising and has the potential to be used in the diagnosis of superficial vein insufficiency.2
Recently published data from Florida have shown a very high sensitivity and specificity (98% and 100% respectively) using thermography to detect superficial insufficiency when compared with the gold standard of duplex ultrasound.
Further research in the field will look at other clinical indications such as wound care and dermatology to allow us to better understand how these 86,400 points of thermo-visual data can bring previously unseen insights into disease that can aid with diagnosis and treatment.
Thermal imaging (TI) has been useful in aiding physicians in detecting body surface temperature changes since 19563. Though TI has been common practice in algology (study of algae) and veterinary care and as an adjunct in diagnostic studies for breast cancer, chiropractic care, and sports medicine, today we see a new use for this technology as it is in high demand as a screening tool present in nearly every place of high public traffic.4
It’s truly no wonder why interest from other health care practices, as well as support from health-care insurance providers, is quickly rising in regard to the vast potential of thermographic technology.
Thermography screening became more largely recognized in human medicine for its use as an adjunctive diagnostic tool in the detection of cancer. Approved by the FDA in 1982, the goal for TI was to assist in the early detection of breast cancer. As in various pathological changes in the body, tumors generally have an increased blood supply, which can produce greater surface heat being detected over a specific location. However, due to the denseness of breast tissue, the sensitivity and specificity of this exam relegates it to adjunctive use with mammography and not as a stand-alone diagnostic tool.
The use of thermography has the potential to be useful as a daily diagnostic tool or as an enhancement to gold-standard testing. The vast capabilities include being applied at safe distances of 1–2 meters for non-contact temperature scans to pain evaluation in critical surgical patients and even to the detection of clinical abnormalities such as phlebitis in ICU patients.5,6
Thermography, if used properly, can detect and map pathological temperature changes, allowing for the possibility of detecting abnormal temperature patterns in the extremities for patients who suffer from diabetes or vascular disorders. This change in gradient can be used in early detection and prevention of various types of wounds.
Research regarding orthopedic medicine has proven TI to be beneficial in the differentiation of significant and minor soft tissue injury.7 It has even been used to track the progression of diseases such as Muscular Dystrophy. Because of the pathology behind the various layers of the skin, the use of TI has the potential to expand to medical practices such as dermatology, wound care, and burn clinics. There has been speculation and interest around the use of TI for patients with venous insufficiency and new studies are reflecting the considered value of TI as a supplementary diagnostic tool for lymphedema and venous leg ulcers.
One of the largest companies in the world, United Healthcare, is among those who are addressing the possibilities of thermography. Along with CMS, they have designated a few procedural codes for thermography. United Healthcare’s policy, updated in May 2021, addresses studies regarding thermography and TI in plastic surgery, stroke patients, peripheral arterial disease (PAD), early detection of diabetes, and various other acute and chronic conditions.
Many of the reports cited have a common conclusion. Results in using thermography as an adjunct tool were positive but further research and larger studies need to be conducted to support the finding evidence.8 It is crucial that we heed their advice and continue to develop research regarding TI to expand and support this technology as its value has become very clear.
Though some still question the benefit of TI, knowledge, and evolution behind the science of infrared technology, thermoregulation and the pathophysiological processes of the human body have greatly expanded in recent years. Today’s thermographic cameras have the ability to measure temperature readings to 0.058 and at a sensitivity of 95% with specificity at 100% when compared to the gold standard methods. Thermography is a safe, cost-effective, non-invasive adjunct tool that is available and should be applied in every aspect of health care.
About The Cardiovascular Institute of the South
The Cardiovascular Institute of the South is a research institute committed to remaining at the forefront of technology and leading the world in cardiovascular and peripheral vascular disease prevention, detection, and treatment. With a never-ending pursuit of knowledge, we are excited about the future of thermography as a tool for attaining adjunct imaging with no discomfort to our patients and maintaining our pledge for compassionate care. We are eager to pursue research endeavors related to this advancing technology and look forward to sharing new findings with our community and with present and future leaders in the field of medicine.
Should you have an interest in learning more about this advancing technology or wish to be involved in expanding studies into thermography, we have begun a joint research initiative with USA Therm from Aventura, Florida. Our joint “pioneer” program is accepting inquiries from those who would like to be a part of this cutting-edge technology. Visit https://www.usatherm.com/pioneer.
References
1. Holm J, Kellett JG, Jensen NH, Hansen SN, Jensen K, Braband M. Prognostic value of infrared thermography in an emergency department. European Journal of Emergency Medicine. 2018. DOI: 10.1097/MEJ.0000000000000441.
2. Cholewka, A., Kajewska, J., Marek, K. et al. How to use thermal imaging in venous insufficiency?. J Therm Anal Calorim 130, 1317–1326 (2017). https://doi.org/10.1007/s10973-017-6141-7
3. Fraser J. Hot bodies; Cold War: the forgotten history of breast thermography [published correction appears in CMAJ. 2017 Jun 19;189(24):E842]. CMAJ. 2017;189(15):E573-E575. doi:10.1503/cmaj.160833
4. Casas-Alvarado A, Mota-Rojas D, Hernández-Ávalos I, et al. Advances in infrared thermography: Surgical aspects, vascular changes, and pain monitoring in veterinary medicine. J Therm Biol. 2020;92:102664. doi:10.1016/j.jtherbio.2020.102664
5. Lahiri BB, Bagavathiappan S, Jayakumar T, Philip J. Medical applications of infrared thermography: A review. Infrared Phys Technol. 2012;55(4):221-235. doi:10.1016/j.infrared.2012.03.007
6. Doesburg F, Smit JM, Paans W, Onrust M, Nijsten M, Dieperink W. Use of infrared thermography in the detection of superficial phlebitis in adult intensive care unit patients: A prospective single-center observational study. POne. 2019. https://doi.org/10.1371/journal.pone.0213754
7. Ioannou S. Functional Infrared Thermal Imaging: A Contemporary Tool in Soft Tissue Screening. Sci Rep. 2020;10(1):9303. Published 2020 Jun
9. doi:10.1038/s41598-020-66397-9
8. Thermography: United Healthcare Commercial Medical Policy. United Healthcare Services, Inc. Updated 05/01/2021. Accessed from https://www.uhcprovider.com/content/dam/provider/docs/public/policies/comm-medical-drug/thermography.pdf#page1
