Infrared Thermography-A Novel Technique for Assessment of Regional Blood Flow/Perfusion?
There has been increasing emphasis on non-invasive assessment of regional perfusion abnormality/ endothelial dysfunction-which have often been linked to poor cardiovascular outcomes. Infrared thermography (IT) is a ‘non-contact’ imaging modality which detects infrared heat from the surface of the body and quantifies skin temperature as a surrogate for blood flow for specific vascular territories.2 It may be used to study physiologic blood flow abnormalities related to temperature distribution in various conditions specifically in the extremities. It produces a visual heat-map display and allows objective temperature measurement with regional temperature assessment to evaluate vascular perfusion.2 IT has the advantages of being noninvasive, fast, reliable, with non-contact, capable of producing multiple recordings at short time intervals, and safe for patients and doctors.1 The temperatures of a large number of points on the area of skin under consideration is measured, and a ‘heat map’ is subsequently produced with color coding for areas of relative ‘colder’ temperatures, or elevated temperatures as a consequence of local inflammation, after acclimatization of the individual to ambient temperature.
Of particular interest for practitioners of cardiovascular medicine is the utility of IT in the assessment of peripheral vascular diseases and more specifically in the assessment of hand perfusion after trans radial cardiac catheterization. IT has been shown to be capable of diagnosing lower extremity peripheral arterial diseases, especially post exercise1. Of possible greater interest to the interventional community specifically, IT has recently shown2 a possible way to assess for microvascular dysfunction in the circulation of the hand post trans radial cardiac catheterization. There appears to be some concern for patients with poor circulation of the ulnar artery. As a practicing interventional cardiologist, after recently becoming aware of this modality, it appears to be a novel way to monitor for hand microvascular dysfunction in real-time, especially for prolonged radial cases or those with compromised baseline ulnar artery flow. There also appears to be scope for future research in identifying best practices and interventions to improve such microvascular dysfunction, should they occur. It would be interesting to hear of experience(s) in using this novel technology!
- Huang CL, Wu YW, Hwang CL, Jong YS, Chao CL, Chen WJ, et al. The application of infrared thermography in evaluation of patients at high risk for lower extremity peripheral arterial disease. J Vasc Surg 2011;54:1074–80.
- Maki KA, Griza DS, Phillips SA, Wolska BM, Vidovich MI. Altered Hand Temperatures Following Transradial Cardiac Catheterization: A Thermography Study. Cardiovasc Revasc Med. 2019 Jun;20(6):496-502. doi: 10.1016/j.carrev.2018.07.024.