Authors (including presenting author) :
Tse OH(1), Hui KW(1), Pang YC (2), Lo STW (1), Chan KH (1)
Affiliation :
(1) Department of Surgery, Pamela Youde Nethersole Eastern Hospital, (2) Department of Surgery, Queen Mary Hospital
Introduction :
Tissue ischemia occurs when insufficient blood flow and oxygen supply to body cells. This can result in gradual tissue damage, potentially culminating in gangrene and tissue necrosis. While visual observation can indicate gangrenous changes in the lower limbs, accurately assessing the extent of tissue damage poses a significant challenge.
Near-infrared (NIR) imaging technology uses wavelengths beyond the visible spectrum, enabling it to penetrate complex tissues and measure tissue oxygen saturation (StO₂) in superficial areas. NIR light is weakly absorbed but highly scattered by tissue, allowing deeper penetration than ultraviolet light. By utilizing an NIR camera, it quantifies the relative amounts of oxygenated and deoxygenated hemoglobin in microcirculation
Objectives :
This study aims to evaluate the effectiveness of NIR imaging in monitoring wound healing progress in patients with peripheral arterial disease. NIR imaging provides a tissue oxygenation map that aids in:
- Assessing therapeutic efficacy of post-revascularization
- Tracking wound healing
- Evaluating tissue viability to enhance medical decision-making accuracy
Methodology :
From September 1 to November 31, 2024, sixteen patients with arterial wounds in the lower limbs were evaluated using an NIR camera both pre- and post-lower limb angioplasty in PYNEH. A single trained operator was designated to ensure consistency throughout the assessments. The camera was calibrated according to manufacturer instructions before each use. Then StO₂ levels were measured to monitor wound healing progress everyday
Result & Outcome :
The NIR camera revealed a 13% to 78% improvement in StO₂ when comparing pre- and post-lower limb angioplasty measurements. These findings demonstrated that NIR imaging can effectively visualize blood flow in wound areas and identify regions with compromised circulation that may impede healing. Furthermore, NIR imaging provides real-time information on wound status, enabling healthcare providers to make treatment decisions in wound debridement or revascularization if necessary. Despite its benefits, NIR camera has notable limitations, including the variability in tissue composition as different tissues absorb and scatter NIR differently and the complex interpretation of wound may has variation.
Conclusion
NIR imaging is a valuable tool in assessing and managing wound conditions for patients with peripheral arterial disease, offering insights that can enhance treatment outcomes. Nonetheless, clinicians must be aware of its limitations and ensure proper training for accurate interpretation.
References
Dereck, W. Paul, M.S. Pejhman, G. Jessica, C. (2015). Noninvasive imaging technologies for cutaneous wound assessment: a review. 23(2).
Arnold, J. & Marmolejo, V. (2021). Interpretation of near-infrared imaging in acute and chronic wound care. 11(5).
Sowa, M.G., Wen, C.K. & Armstrong, D.G. (2016). Review of near-infrared methods for wound assessment. Journal of Biomedical Optics. 21(9).
