Infrared Thermography for Pre- and Postrevascularization Assessment of Ischemic Limbs

Background: Objective assessment of tissue perfusion after lower-limb revascularization remains challenging. Angiographic vessel opening may not directly correlate to increased tissue perfusion and wound healing in many cases. Infrared thermography (IRT) provides a non-contact and reproducible method of assessing microcirculatory improvement through temperature mapping. Materials and Methods: Thirty patients with critical limb ischemia undergoing surgical or endovascular revascularization were prospectively evaluated. Only Rutherford 4–6 was included in the study. All thermographic measurements were performed in a temperature-controlled 26°C environment using a long-wave infrared camera. Mean surface temperatures were recorded for the affected foot and anterior chest, and the affected-to-chest temperature ratio and absolute change (ΔT) were calculated. Clinical outcomes were correlated with thermal changes. Results: The mean prerevascularization foot temperature was 29.7°C, ±1.1°C, which increased to 32.2°C, ±1.5°C postrevascularization ( P < 0.001). The affected-to-chest temperature ratio improved from 0.85 ± 0.03 to 0.92 ± 0.04 ( P < 0.001). Patients showing ≥2°C improvement demonstrated higher rates of wound healing and limb salvage ( r = 0.62, P < 0.01). Conclusion: Measurement of skin temperature of the limbs using a thermal camera is feasible and reproducible. IRT effectively demonstrates perfusion improvement following revascularization and provides an objective adjunct to clinical and hemodynamic evaluation in a temperature-controlled environment.