Smartphone-based Infrared Thermography – A Novel Approach to Evaluate the Treatment Effect of Revascularization Procedure in Peripheral Arterial Disease Patients

Background: Peripheral Arterial Disease (PAD) is a progressive vascular disorder that compromises blood flow to the extremities, leading to ischemic symptoms such as claudication, rest pain, and tissue loss. Infrared thermography (IRT) is a non-contact imaging modality that detects cutaneous temperature changes, reflecting tissue perfusion status. This study explores the utility of smartphone-based infrared thermography in assessing perfusion before and after revascularization in PAD patients. Methods: A prospective observational study was conducted from July 2020 to September 2021, including 52 patients with PAD undergoing revascularization. Baseline and post-intervention perfusion assessments were performed using Ankle-Brachial Index (ABI) and Thermal Ankle-Brachial Index (TABI), calculated from temperature readings obtained using the FLIR One Pro infrared thermal camera. Measurements were taken pre-intervention, at discharge, and one-month post-intervention. Statistical analysis was performed to evaluate correlations between ABI, TABI, and limb temperature. Results: A strong positive correlation was observed between ABI and lower extremity (LE) temperature pre-intervention ( r = 0.973, P < 0.001) and post-intervention at discharge ( r = 0.682, P < 0.001). Post-revascularization, there was a significant improvement in ABI (Δ0.38 ± 0.20, P < 0.001), TABI (Δ0.09 ± 0.053, P < 0.001), and LE temperature (Δ10.2 ± 5.4℉, P < 0.001). These improvements persisted at one-month follow-up, validating smartphone-based IRT as a reliable perfusion assessment tool. Conclusion: Smartphone-based thermography is a promising, non-invasive, cost-effective adjunct to ABI for evaluating revascularization outcomes in PAD patients. Its portability and real-time assessment capability make it a viable alternative in clinical practice for rapid perfusion assessment.